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Donkey anti-Rabbit IgG (H+L) Highly Cross-Adsorbed Secondary Antibody, Alexa Fluor 594

RRID:AB_141637

Antibody ID

AB_141637

Target Antigen

Rabbit IgG (H+L) Highly Cross-Adsorbed rabbit

Proper Citation

(Thermo Fisher Scientific Cat# A-21207, RRID:AB_141637)

Clonality

polyclonal antibody

Comments

Applications: Flow (1-10 µg/mL), IHC (1-10 µg/mL), IF (2 µg/mL), ICC (2 µg/mL)

Host Organism

donkey

Vendor

Thermo Fisher Scientific Go To Vendor

Cat Num

A-21207 also A21207

Publications that use this research resource

Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study.

  • Christiansen AT
  • J. Comp. Neurol.
  • 2018 Aug 15

Literature context:


Abstract:

Neuropeptide Y (NPY) is a peptide neurotransmitter abundantly expressed in the mammalian retina. Since its discovery, NPY has been studied in retinas of several species, but detailed characterization of morphology, cell-type, and connectivity has never been conducted in larger mammals including humans and pigs. As the pig due to size and cellular composition is a well-suited animal for retinal research, we chose to compare the endogenous NPY system of the human retina to that of pigs to support future research in this field. In the present study, using immunohistochemistry, confocal microscopy and 3D reconstructions, we found NPY to be expressed in GABAergic and calretinin-immunoreactive (-ir) amacrine cells of both species as well as parvalbumin-ir amacrine cells of humans. Furthermore, we identified at least two different types of medium- to wide-field NPY-ir amacrine cells. Finally, we detected likely synaptic appositions between the NPY-ir amacrine cells and melanopsin- and nonmelanopsin-ir ganglion cells, GABAergic and dopaminergic amacrine cells, rod bipolar cells, and horizontal cells, suggesting that NPY-ir cells play diverse roles in modulation of both image and non-image forming retinal signaling. These findings extend existing knowledge on NPY and NPY-expressing cells in the human and porcine retina showing a high degree of comparability. The extensive distribution and connectivity of NPY-ir cells described in the present study further highlights the potential importance of NPY signaling in retinal function.

Funding information:
  • NIA NIH HHS - R01 AG012423(United States)

Conditional Deletion of FOXL2 and SMAD4 in Gonadotropes of Adult Mice Causes Isolated FSH Deficiency.

  • Li Y
  • Endocrinology
  • 2018 Jul 1

Literature context:


Abstract:

The glycoprotein FSH, a product of pituitary gonadotrope cells, regulates ovarian follicle development in females and spermatogenesis in males. FSH is a heterodimer of the common α gonadotropin subunit and the hormone-specific FSHβ subunit (a product of the Fshb gene). Using a conditional knockout approach (Cre-lox), we previously demonstrated that Fshb expression in mice depends on the transcription factors forkhead box L2 (FOXL2) and SMAD4. Deletion of Foxl2 or Smad4 alone led to FSH deficiency, female subfertility, and oligozoospermia in males. Simultaneous deletion of the two genes yielded a greater suppression of FSH and female sterility. The Cre-driver used previously was first active during embryonic development. Therefore, it is unclear whether FOXL2 and SMAD4 play important roles in the development or adult function of gonadotropes, or both. To address this question, we developed a tamoxifen-inducible Cre-driver line, which enabled Foxl2 and Smad4 gene deletions in gonadotropes of adult mice. After tamoxifen treatment, females with previously demonstrated fertility exhibited profound reductions in FSH levels, arrested ovarian follicle development, and sterility. FSH levels were comparably reduced in males 1 or 2 months after treatment; however, spermatogenesis was unaffected. These data indicate that (1) FOXL2 and SMAD4 are necessary to maintain FSH synthesis in gonadotrope cells of adult mice, (2) FSH is essential for female reproduction but appears to be unnecessary for the maintenance of spermatogenesis in adult male mice, and (3) the inducible Cre-driver line developed here provides a powerful tool to interrogate gene function in gonadotrope cells of adult mice.

Funding information:
  • NHLBI NIH HHS - R01 HL101200(United States)

Dual leucine zipper kinase is required for mechanical allodynia and microgliosis after nerve injury.

  • Wlaschin JJ
  • Elife
  • 2018 Jul 3

Literature context:


Abstract:

Neuropathic pain resulting from nerve injury can become persistent and difficult to treat but the molecular signaling responsible for its development remains poorly described. Here, we identify the neuronal stress sensor dual leucine zipper kinase (DLK; Map3k12) as a key molecule controlling the maladaptive pathways that lead to pain following injury. Genetic or pharmacological inhibition of DLK reduces mechanical hypersensitivity in a mouse model of neuropathic pain. Furthermore, DLK inhibition also prevents the spinal cord microgliosis that results from nerve injury and arises distant from the injury site. These striking phenotypes result from the control by DLK of a transcriptional program in somatosensory neurons regulating the expression of numerous genes implicated in pain pathogenesis, including the immune gene Csf1. Thus, activation of DLK is an early event, or even the master regulator, controlling a wide variety of pathways downstream of nerve injury that ultimately lead to chronic pain.

Funding information:
  • National Center for Complementary and Integrative Health - Intramural Research Program()
  • National Institute of Child Heath and Human Development - Intramural Research Program()
  • National Institutes of Health - Intramural Research Program - DDIR Innovation Award()
  • NCI NIH HHS - P30 CA33572(United States)

A Sialylated Voltage-Dependent Ca2+ Channel Binds Hemagglutinin and Mediates Influenza A Virus Entry into Mammalian Cells.

  • Fujioka Y
  • Cell Host Microbe
  • 2018 Jun 13

Literature context:


Abstract:

Influenza A virus (IAV) infection is initiated by the attachment of the viral glycoprotein hemagglutinin (HA) to sialic acid on the host cell surface. However, the sialic acid-containing receptor crucial for IAV infection has remained unidentified. Here, we show that HA binds to the voltage-dependent Ca2+ channel Cav1.2 to trigger intracellular Ca2+ oscillations and subsequent IAV entry and replication. IAV entry was inhibited by Ca2+ channel blockers (CCBs) or by knockdown of Cav1.2. The CCB diltiazem also inhibited virus replication in vivo. Reintroduction of wild-type but not the glycosylation-deficient mutants of Cav1.2 restored Ca2+ oscillations and virus infection in Cav1.2-depleted cells, demonstrating the significance of Cav1.2 sialylation. Taken together, we identify Cav1.2 as a sialylated host cell surface receptor that binds HA and is critical for IAV entry.

Funding information:
  • Wellcome Trust - 089275(United Kingdom)

Short-Term, Intermittent Fasting Induces Long-Lasting Gut Health and TOR-Independent Lifespan Extension.

  • Catterson JH
  • Curr. Biol.
  • 2018 Jun 4

Literature context:


Abstract:

Intermittent fasting (IF) can improve function and health during aging in laboratory model organisms, but the mechanisms at work await elucidation. We subjected fruit flies (Drosophila melanogaster) to varying degrees of IF and found that just one month of a 2-day fed:5-day fasted IF regime at the beginning of adulthood was sufficient to extend lifespan. This long-lasting, beneficial effect of early IF was not due to reduced fecundity. Starvation resistance and resistance to oxidative and xenobiotic stress were increased after IF. Early-life IF also led to higher lipid content in 60-day-old flies, a potential explanation for increased longevity. Guts of flies 40 days post-IF showed a significant reduction in age-related pathologies and improved gut barrier function. Improved gut health was also associated with reduced relative bacterial abundance. Early IF thus induced profound long-term changes. Pharmacological and genetic epistasis analysis showed that IF acted independently of the TOR pathway because rapamycin and IF acted additively to extend lifespan, and global expression of a constitutively active S6K did not attenuate the IF-induced lifespan extension. We conclude that short-term IF during early life can induce long-lasting beneficial effects, with robust increase in lifespan in a TOR-independent manner, probably at least in part by preserving gut health.

Funding information:
  • NCI NIH HHS - R01 CA163772(United States)

A Linc1405/Eomes Complex Promotes Cardiac Mesoderm Specification and Cardiogenesis.

  • Guo X
  • Cell Stem Cell
  • 2018 Jun 1

Literature context:


Abstract:

Large intergenic non-coding RNAs (lincRNAs) play widespread roles in epigenetic regulation during multiple differentiation processes, but little is known about their mode of action in cardiac differentiation. Here, we identified the key roles of a lincRNA, termed linc1405, in modulating the core network of cardiac differentiation by functionally interacting with Eomes. Chromatin- and RNA-immunoprecipitation assays showed that exon 2 of linc1405 physically mediates a complex consisting of Eomes, trithorax group (TrxG) subunit WDR5, and histone acetyltransferase GCN5 binding at the enhancer region of Mesp1 gene and activates its expression during cardiac mesoderm specification of embryonic stem cells. Importantly, linc1405 co-localizes with Eomes, WDR5, and GCN5 at the primitive streak, and linc1405 depletion impairs heart development and function in vivo. In summary, linc1405 mediates a Eomes/WDR5/GCN5 complex that contributes to cardiogenesis, highlighting the critical roles of lincRNA-based complexes in the epigenetic regulation of cardiogenesis in vitro and in vivo.

Funding information:
  • NCATS NIH HHS - UL1TR000124(United States)

Defects in the Alternative Splicing-Dependent Regulation of REST Cause Deafness.

  • Nakano Y
  • Cell
  • 2018 Jun 25

Literature context:


Abstract:

The DNA-binding protein REST forms complexes with histone deacetylases (HDACs) to repress neuronal genes in non-neuronal cells. In differentiating neurons, REST is downregulated predominantly by transcriptional silencing. Here we report that post-transcriptional inactivation of REST by alternative splicing is required for hearing in humans and mice. We show that, in the mechanosensory hair cells of the mouse ear, regulated alternative splicing of a frameshift-causing exon into the Rest mRNA is essential for the derepression of many neuronal genes. Heterozygous deletion of this alternative exon of mouse Rest causes hair cell degeneration and deafness, and the HDAC inhibitor SAHA (Vorinostat) rescues the hearing of these mice. In humans, inhibition of the frameshifting splicing event by a novel REST variant is associated with dominantly inherited deafness. Our data reveal the necessity for alternative splicing-dependent regulation of REST in hair cells, and they identify a potential treatment for a group of hereditary deafness cases.

Funding information:
  • NIMH NIH HHS - 5 F32 MH064339-03(United States)

Myoepithelial Cells of Submucosal Glands Can Function as Reserve Stem Cells to Regenerate Airways after Injury.

  • Tata A
  • Cell Stem Cell
  • 2018 May 3

Literature context:


Abstract:

Cells demonstrate plasticity following injury, but the extent of this phenomenon and the cellular mechanisms involved remain underexplored. Using single-cell RNA sequencing (scRNA-seq) and lineage tracing, we uncover that myoepithelial cells (MECs) of the submucosal glands (SMGs) proliferate and migrate to repopulate the airway surface epithelium (SE) in multiple injury models. Specifically, SMG-derived cells display multipotency and contribute to basal and luminal cell types of the SMGs and SE. Ex vivo expanded MECs have the potential to repopulate and differentiate into SE cells when grafted onto denuded airway scaffolds. Significantly, we find that SMG-like cells appear on the SE of both extra- and intra-lobular airways of large animal lungs following severe injury. We find that the transcription factor SOX9 is necessary for MEC plasticity in airway regeneration. Because SMGs are abundant and present deep within airways, they may serve as a reserve cell source for enhancing human airway regeneration.

Funding information:
  • NHLBI NIH HHS - R00 HL127181()
  • NIDDK NIH HHS - DK59630(United States)
  • NIEHS NIH HHS - U01 ES017219()

De Novo Macrocyclic Peptide Inhibitors of Hepatitis B Virus Cellular Entry.

  • Passioura T
  • Cell Chem Biol
  • 2018 May 2

Literature context:


Abstract:

Hepatitis B virus (HBV) constitutes a significant public health burden, and currently available treatment options are not generally curative, necessitating the development of new therapeutics. Here we have applied random non-standard peptide integrated discovery (RaPID) screening to identify small macrocyclic peptide inhibitors of HBV entry that target the cell-surface receptor for HBV, sodium taurocholate cotransporting polypeptide (NTCP). In addition to their anti-HBV activity, these molecules also inhibit cellular entry by the related hepatitis D virus (HDV), and are active against diverse strains of HBV (including clinically relevant nucleos(t)ide analog-resistant and vaccine escaping strains). Importantly, these macrocyclic peptides, in contrast to other NTCP-binding HBV entry inhibitors, exhibited no inhibition of NTCP-mediated bile acid uptake, making them appealing candidates for therapeutic development.

Funding information:
  • Division of Molecular and Cellular Biosciences - MCB-1121334()
  • NCI NIH HHS - 1R21CA141009(United States)

Preoptic leptin signaling modulates energy balance independent of body temperature regulation.

  • Yu S
  • Elife
  • 2018 May 15

Literature context:


Abstract:

The adipokine leptin acts on the brain to regulate energy balance but specific functions in many brain areas remain poorly understood. Among these, the preoptic area (POA) is well known to regulate core body temperature by controlling brown fat thermogenesis, and we have previously shown that glutamatergic, long-form leptin receptor (Lepr)-expressing neurons in the POA are stimulated by warm ambient temperature and suppress energy expenditure and food intake. Here we further investigate the role of POA leptin signaling in body weight regulation and its relationship to body temperature regulation in mice. We show that POA Lepr signaling modulates energy expenditure in response to internal energy state, and thus contributes to body weight homeostasis. However, POA leptin signaling is not involved in ambient temperature-dependent metabolic adaptations. Our study reveals a novel cell population through which leptin regulates body weight.

Funding information:
  • ADA Foundation - ADA1-17-PDF-138()
  • American Heart Association - AHA053298N; AHA17GRNT32960003()
  • Intramural NIH HHS - ZIA AR041155-05(United States)
  • National Institute of Diabetes and Digestive and Kidney Diseases - 1DK117281()
  • National Institute of Diabetes and Digestive and Kidney Diseases - 1HL122829()
  • National Institute of Diabetes and Digestive and Kidney Diseases - DK047348()
  • National Institute of Diabetes and Digestive and Kidney Diseases - DK099598()
  • National Institute of Diabetes and Digestive and Kidney Diseases - DK101379()
  • National Institute of Diabetes and Digestive and Kidney Diseases - DK105032()
  • National Institute of Diabetes and Digestive and Kidney Diseases - P20GM103528()
  • National Institute of Diabetes and Digestive and Kidney Diseases - P30DK072476()
  • National Institute of Diabetes and Digestive and Kidney Diseases - R01DK092587()
  • U.S. Department of Agriculture - USDA/CRIS3092-5-001-059()

Nav1.1-Overexpressing Interneuron Transplants Restore Brain Rhythms and Cognition in a Mouse Model of Alzheimer's Disease.

  • Martinez-Losa M
  • Neuron
  • 2018 Apr 4

Literature context:


Abstract:

Inhibitory interneurons regulate the oscillatory rhythms and network synchrony that are required for cognitive functions and disrupted in Alzheimer's disease (AD). Network dysrhythmias in AD and multiple neuropsychiatric disorders are associated with hypofunction of Nav1.1, a voltage-gated sodium channel subunit predominantly expressed in interneurons. We show that Nav1.1-overexpressing, but not wild-type, interneuron transplants derived from the embryonic medial ganglionic eminence (MGE) enhance behavior-dependent gamma oscillatory activity, reduce network hypersynchrony, and improve cognitive functions in human amyloid precursor protein (hAPP)-transgenic mice, which simulate key aspects of AD. Increased Nav1.1 levels accelerated action potential kinetics of transplanted fast-spiking and non-fast-spiking interneurons. Nav1.1-deficient interneuron transplants were sufficient to cause behavioral abnormalities in wild-type mice. We conclude that the efficacy of interneuron transplantation and the function of transplanted cells in an AD-relevant context depend on their Nav1.1 levels. Disease-specific molecular optimization of cell transplants may be required to ensure therapeutic benefits in different conditions.

Funding information:
  • NCRR NIH HHS - C06 RR018928()
  • NIA NIH HHS - F32 AG043301()
  • NIA NIH HHS - R01 AG030207()
  • NIA NIH HHS - R01 AG036884()
  • NIA NIH HHS - R01 AG047313()
  • NIA NIH HHS - R01 AG051390()
  • NIA NIH HHS - R01 AG054214()
  • NIAID NIH HHS - R01 AI059738-05(United States)
  • NINDS NIH HHS - P30 NS065780()
  • NINDS NIH HHS - R01 NS041787()
  • NINDS NIH HHS - U54 NS100717()

Sustained activation of ERK1/2 MAPK in Schwann cells causes corneal neurofibroma.

  • Bargagna-Mohan P
  • J. Neurosci. Res.
  • 2018 Apr 17

Literature context:


Abstract:

Recent studies have shown that constitutive activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in Schwann cells (SCs) increases myelin thickness in transgenic mice. In this secondary analysis, we report that these transgenic mice develop a postnatal corneal neurofibroma with the loss of corneal transparency by age six months. We show that expansion of non-myelinating SCs, under the control of activated ERK1/2, also drive myofibroblast differentiation that derives from both SC precursors and resident corneal keratocytes. Further, these mice also harbor activated mast cells in the central cornea, which contributes to pathological corneal neovascularization and fibrosis. This breach of corneal avascularity and immune status is associated with the growth of the tumor pannus, resulting in a corneal stroma that is nearly four times its normal size. In corneas with advanced disease, some axons became ectopically myelinated, and the disruption of Remak bundles is evident. To determine whether myofibroblast differentiation was linked to vimentin, we examined the levels and phosphorylation status of this fibrotic biomarker. Concomitant with the early upregulation of vimentin, a serine 38-phosphorylated isoform of vimentin (pSer38vim) increased in SCs, which was attributed primarily to the soluble fraction of protein-not the cytoskeletal portion. However, the overexpressed pSer38vim became predominantly cytoskeletal with the growth of the corneal tumor. Our findings demonstrate an unrecognized function of ERK1/2 in the maintenance of corneal homeostasis, wherein its over-activation in SCs promotes corneal neurofibromas. This study is also the first report of a genetically engineered mouse that spontaneously develops a corneal tumor.

Funding information:
  • NEI NIH HHS - R01 EY016782()
  • NINDS NIH HHS - R01 NS038878()
  • NINDS NIH HHS - R21 NS081948()

Perineuronal nets in subcortical auditory nuclei of four rodent species with differing hearing ranges.

  • Beebe NL
  • J. Comp. Neurol.
  • 2018 Apr 15

Literature context:


Abstract:

Perineuronal nets (PNs) are aggregates of extracellular matrix molecules that surround some neurons in the brain. While PNs occur widely across many cortical areas, subcortical PNs are especially associated with motor and auditory systems. The auditory system has recently been suggested as an ideal model system for studying PNs and their functions. However, descriptions of PNs in subcortical auditory areas vary, and it is unclear whether the variation reflects species differences or differences in staining techniques. Here, we used two staining techniques (one lectin stain and one antibody stain) to examine PN distribution in the subcortical auditory system of four different species: guinea pigs (Cavia porcellus), mice (Mus musculus, CBA/CaJ strain), Long-Evans rats (Rattus norvegicus), and naked mole-rats (Heterocephalus glaber). We found that some auditory nuclei exhibit dramatic differences in PN distribution among species while other nuclei have consistent PN distributions. We also found that PNs exhibit molecular heterogeneity, and can stain with either marker individually or with both. PNs within a given nucleus can be heterogeneous or homogenous in their staining patterns. We compared PN staining across the frequency axes of tonotopically organized nuclei and among species with different hearing ranges. PNs were distributed non-uniformly across some nuclei, but only rarely did this appear related to the tonotopic axis. PNs were prominent in all four species; we found no systematic relationship between the hearing range and the number, staining patterns or distribution of PNs in the auditory nuclei.

Funding information:
  • Biotechnology and Biological Sciences Research Council - BBF0143921(United Kingdom)

Systematic Characterization of Stress-Induced RNA Granulation.

  • Namkoong S
  • Mol. Cell
  • 2018 Apr 5

Literature context:


Abstract:

Upon stress, cytoplasmic mRNA is sequestered to insoluble ribonucleoprotein (RNP) granules, such as the stress granule (SG). Partially due to the belief that translationally suppressed mRNAs are recruited to SGs in bulk, stress-induced dynamic redistribution of mRNA has not been thoroughly characterized. Here, we report that endoplasmic reticulum (ER) stress targets only a small subset of translationally suppressed mRNAs into the insoluble RNP granule fraction (RG). This subset, characterized by extended length and adenylate-uridylate (AU)-rich motifs, is highly enriched with genes critical for cell survival and proliferation. This pattern of RG targeting was conserved for two other stress types, heat shock and arsenite toxicity, which induce distinct responses in the total cytoplasmic transcriptome. Nevertheless, stress-specific RG-targeting motifs, such as guanylate-cytidylate (GC)-rich motifs in heat shock, were also identified. Previously underappreciated, transcriptome profiling in the RG may contribute to understanding human diseases associated with RNP dysfunction, such as cancer and neurodegeneration.

Funding information:
  • NIAID NIH HHS - R01 AI043477(United States)

Immunohistochemical Procedures for Characterizing the Retinal Expression Patterns of Cre Driver Mouse Lines.

  • Lu Q
  • Methods Mol. Biol.
  • 2018 Apr 26

Literature context:


Abstract:

The retina is a thin neural tissue sitting on the backside of the eye, composed of light-sensing cells, interneurons, and output ganglion neurons. The latter send electrical signals to higher visual centers in the brain. Transgenic mouse lines are becoming one of the most valuable mammalian animal models for the study of visual signal processing within the retina. Especially, the generation of Cre recombinase transgenic mouse lines provides a powerful tool for genetic manipulation. A key step for the utilization of transgenic lines is the characterization of their transgene expression patterns in the retina. Here we describe a standard protocol for characterizing the expression pattern of the Cre recombinase or fluorescent proteins in the retina with an immunohistochemical approach.

Ventral pallidal encoding of reward-seeking behavior depends on the underlying associative structure.

  • Richard JM
  • Elife
  • 2018 Mar 22

Literature context:


Abstract:

Despite its being historically conceptualized as a motor expression site, emerging evidence suggests the ventral pallidum (VP) plays a more active role in integrating information to generate motivation. Here, we investigated whether rat VP cue responses would encode and contribute similarly to the vigor of reward-seeking behaviors trained under Pavlovian versus instrumental contingencies, when these behavioral responses consist of superficially similar locomotor response patterns but may reflect distinct underlying decision-making processes. We find that cue-elicited activity in many VP neurons predicts the latency of instrumental reward seeking, but not of Pavlovian response latency. Further, disruption of VP signaling increases the latency of instrumental but not Pavlovian reward seeking. This suggests that VP encoding of and contributions to response vigor are specific to the ability of incentive cues to invigorate reward-seeking behaviors upon which reward delivery is contingent.

Funding information:
  • National Institute on Alcohol Abuse and Alcoholism - AA014925()
  • National Institute on Alcohol Abuse and Alcoholism - AA022290()
  • NCI NIH HHS - CA-25000(United States)
  • NIAAA NIH HHS - F32 AA022290()
  • NIAAA NIH HHS - K99 AA025384()

The SS18-SSX Oncoprotein Hijacks KDM2B-PRC1.1 to Drive Synovial Sarcoma.

  • Banito A
  • Cancer Cell
  • 2018 Mar 12

Literature context:


Abstract:

Synovial sarcoma is an aggressive cancer invariably associated with a chromosomal translocation involving genes encoding the SWI-SNF complex component SS18 and an SSX (SSX1 or SSX2) transcriptional repressor. Using functional genomics, we identify KDM2B, a histone demethylase and component of a non-canonical polycomb repressive complex 1 (PRC1.1), as selectively required for sustaining synovial sarcoma cell transformation. SS18-SSX1 physically interacts with PRC1.1 and co-associates with SWI/SNF and KDM2B complexes on unmethylated CpG islands. Via KDM2B, SS18-SSX1 binds and aberrantly activates expression of developmentally regulated genes otherwise targets of polycomb-mediated repression, which is restored upon KDM2B depletion, leading to irreversible mesenchymal differentiation. Thus, SS18-SSX1 deregulates developmental programs to drive transformation by hijacking a transcriptional repressive complex to aberrantly activate gene expression.

Funding information:
  • Medical Research Council - G0900871(United Kingdom)
  • NCI NIH HHS - P01 CA013106()
  • NCI NIH HHS - P30 CA008748()
  • NIH HHS - S10 OD020122()

Rapid nonapeptide synthesis during a critical period of development in the prairie vole: plasticity of the paraventricular nucleus of the hypothalamus.

  • Kelly AM
  • Brain Struct Funct
  • 2018 Mar 11

Literature context:


Abstract:

Vasopressin (VP) and oxytocin (OT) are involved in modulating basic physiology and numerous social behaviors. Although the anatomical distributions of nonapeptide neurons throughout development have been described, the functional roles of VP and OT neurons during development are surprisingly understudied, and it is unknown whether they exhibit functional changes throughout early development. We utilized an acute social isolation paradigm to determine if VP and OT neural responses in eight nonapeptide cell groups differ at three different stages of early development in prairie voles. We tested pups at ages that are representative of the three rapid growth stages of the developing brain: postnatal day (PND)2 (closed eyes; poor locomotion), PND9 (eye opening; locomotion; peak brain growth spurt), and PND21 (weaning). Neural responses were examined in pups that (1) were under normal family conditions with their parents and siblings, (2) were isolated from their parents and siblings and then reunited, and (3) were isolated from their parents and siblings. We found that VP and OT neural activity (as assessed via Fos co-localization) did not differ in response to social condition across development. However, remarkably rapid VP and OT synthesis in response to social isolation was observed only in the paraventricular nucleus of the hypothalamus (PVN) and only in PND9 pups. These results suggest that PVN nonapeptide neurons exhibit distinct cellular properties during a critical period of development, allowing nonapeptide neurons to rapidly upregulate peptide production in response to stressors on a much shorter timescale than has been observed in adult animals.

Funding information:
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development - HD079573()
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development - HD081959()
  • NIGMS NIH HHS - GM99722(United States)

Generation of induced pluripotent stem cell line (ZZUi011-A) from urine sample of a normal human.

  • Sun H
  • Stem Cell Res
  • 2018 Mar 27

Literature context:


Abstract:

Urine cells collected from 200mL clean midsection urine of a 25-year-old healthy man were reprogrammed into pluripotent stem cells via Sendai virus delivery system. The induced pluripotent stem cells showed a normal karyotype and exhibited the potential to differentiate into three germ layers in a teratoma assay. This cell line may serve as a useful control for comparison with other pluripotent stem cell lines induced from somatic cells of patients with genetic neurodegenerative disorders.

Funding information:
  • Howard Hughes Medical Institute - (United States)

Developmental History Provides a Roadmap for the Emergence of Tumor Plasticity.

  • Tata PR
  • Dev. Cell
  • 2018 Mar 26

Literature context:


Abstract:

We show that the loss or gain of transcription factor programs that govern embryonic cell-fate specification is associated with a form of tumor plasticity characterized by the acquisition of alternative cell fates normally characteristic of adjacent organs. In human non-small cell lung cancers, downregulation of the lung lineage-specifying TF NKX2-1 is associated with tumors bearing features of various gut tissues. Loss of Nkx2-1 from murine alveolar, but not airway, epithelium results in conversion of lung cells to gastric-like cells. Superimposing oncogenic Kras activation enables further plasticity in both alveolar and airway epithelium, producing tumors that adopt midgut and hindgut fates. Conversely, coupling Nkx2-1 loss with foregut lineage-specifying SOX2 overexpression drives the formation of squamous cancers with features of esophageal differentiation. These findings demonstrate that elements of pathologic tumor plasticity mirror the normal developmental history of organs in that cancer cells acquire cell fates associated with developmentally related neighboring organs.

Funding information:
  • NCI NIH HHS - R01CA172025(United States)
  • NHLBI NIH HHS - K99 HL127181()
  • NHLBI NIH HHS - P30 HL101287()
  • NHLBI NIH HHS - R00 HL127181()
  • NHLBI NIH HHS - R01 HL118185()
  • NIGMS NIH HHS - T32 GM007205()

The Response of Prostate Smooth Muscle Cells to Testosterone Is Determined by the Subcellular Distribution of the Androgen Receptor.

  • Peinetti N
  • Endocrinology
  • 2018 Feb 1

Literature context:


Abstract:

Androgen signaling in prostate smooth muscle cells (pSMCs) is critical for the maintenance of prostate homeostasis, the alterations of which are a central aspect in the development of pathological conditions. Testosterone can act through the classic androgen receptor (AR) in the cytoplasm, eliciting genomic signaling, or through different types of receptors located at the plasma membrane for nongenomic signaling. We aimed to find evidence of nongenomic testosterone-signaling mechanisms in pSMCs and their participation in cell proliferation, differentiation, and the modulation of the response to lipopolysaccharide. We demonstrated that pSMCs can respond to testosterone by a rapid activation of ERK1/2 and Akt. Furthermore, a pool of ARs localized at the cell surface of pSMCs is responsible for a nongenomic testosterone-induced increase in cell proliferation. Through membrane receptor stimulation, testosterone favors a muscle phenotype, indicated by an increase in smooth muscle markers. We also showed that the anti-inflammatory effects of testosterone, capable of attenuating lipopolysaccharide-induced proinflammatory actions, are promoted only by receptors located inside the cell. We postulate that testosterone might perform prohomeostatic effects through intracellular-initiated mechanisms by modulating cell proliferation and inflammation, whereas some pathological, hyperproliferative actions would be induced by membrane-initiated nongenomic signaling in pSMCs.

Funding information:
  • Intramural NIH HHS - ZIA AG000741-09(United States)

Changes in the Cardiac GHSR1a-Ghrelin System Correlate With Myocardial Dysfunction in Diabetic Cardiomyopathy in Mice.

  • Sullivan R
  • J Endocr Soc
  • 2018 Feb 1

Literature context:


Abstract:

Ghrelin and its receptor, the growth hormone secretagogue receptor 1a (GHSR1a), are present in cardiac tissue. Activation of GHSR1a by ghrelin promotes cardiomyocyte contractility and survival, and changes in myocardial GHSR1a and circulating ghrelin track with end-stage heart failure, leading to the hypothesis that GHSR1a is a biomarker for heart failure. We hypothesized that GHSR1a could also be a biomarker for diabetic cardiomyopathy (DCM). We used two models of streptozotocin (STZ)-induced DCM: group 1, adult mice treated with 35 mg/kg STZ for 3 days; and group 2, neonatal mice treated with 70 mg/kg STZ at days 2 and 5 after birth. In group 1, mild fasting hyperglycemia (11 mM) was first detected 8 weeks after the last injection, and in group 2, severe fasting hyperglycemia (20 mM) was first detected 1 to 3 weeks after the last injection. In group 1, left ventricular function was slightly impaired as measured by echocardiography, and Western blot analysis showed a significant decrease in myocardial GHSR1a. In group 2, GHSR1a levels were also decreased as assessed by Cy5-ghrelin(1-19) fluorescence microscopy, and there was a significant negative correlation between GHSR1a levels and glucose tolerance. There were significant positive correlations between GHSR1a and ghrelin and between GHSR1a and sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a), a marker for contractility, but not between GHSR1a and B-type natriuretic peptide, a marker for heart failure. We conclude that the subclinical stage of DCM is accompanied by alterations in the myocardial ghrelin-GHSR1a system, suggesting the possibility of a biomarker for DCM.

Funding information:
  • NIGMS NIH HHS - GM59447(United States)

Abnormal Cell Sorting Underlies the Unique X-Linked Inheritance of PCDH19 Epilepsy.

  • Pederick DT
  • Neuron
  • 2018 Jan 3

Literature context:


Abstract:

X-linked diseases typically exhibit more severe phenotypes in males than females. In contrast, protocadherin 19 (PCDH19) mutations cause epilepsy in heterozygous females but spare hemizygous males. The cellular mechanism responsible for this unique pattern of X-linked inheritance is unknown. We show that PCDH19 contributes to adhesion specificity in a combinatorial manner such that mosaic expression of Pcdh19 in heterozygous female mice leads to striking sorting between cells expressing wild-type (WT) PCDH19 and null PCDH19 in the developing cortex, correlating with altered network activity. Complete deletion of PCDH19 in heterozygous mice abolishes abnormal cell sorting and restores normal network activity. Furthermore, we identify variable cortical malformations in PCDH19 epilepsy patients. Our results highlight the role of PCDH19 in determining cell adhesion affinities during cortical development and the way segregation of WT and null PCDH19 cells is associated with the unique X-linked inheritance of PCDH19 epilepsy.

Human induced pluripotent stem cell line with cytochrome P450 enzyme polymorphism (CYP2C19*2/CYP3A5*3C) generated from lymphoblastoid cells.

  • Lee J
  • Stem Cell Res
  • 2018 Jan 9

Literature context:


Abstract:

Cytochrome P450 (CYP) comprises a superfamily of monooxygenase responsible for the metabolism of xenobiotics and approximately 75% of drugs in use today. Thus, genetic polymorphisms in CYP genes contribute to interindividual differences in hepatic metabolism of drugs, affecting on individual drug efficacy and may cause adverse effects. Here, we generated a human induced pluripotent stem cell (hiPSC) line with pharmacologically important traits (CYP2C19*2/CYP3A5*3C), which are highly polymorphic in Asian from lymphoblastoid cells. This hiPSC line could be a valuable source for predicting individual drug responses in the drug screening process that uses hiPSC-derived somatic cells, including hepatocytes.

Funding information:
  • National Institute of General Medical Sciences - Gradaute Student Fellowship(United States)

Establishment of TUSMi003-A, an induced pluripotent stem cell (iPSC) line from a 62-year old Chinese Han patient with Alzheimer's disease with ApoE3/4 genetic background.

  • Wang Y
  • Stem Cell Res
  • 2018 Jan 13

Literature context:


Abstract:

A 62-year old Chinese Han Alzheimer's disease (AD) female patient with ApoE3/4 genetic background donated her Peripheral blood mononuclear cells (PBMC). The non-integrating episomal vector system was used to reprogrammed PBMCs with the human OKSM transcription factors. The pluripotency of transgene-free iPSCs was confirmed by immunocytochemistry for pluripotency markers and by the ability of the iPSCs to differentiate spontaneously into 3 germ layers in vitro. In addition, the iPSC line displayed a normal karyotype. Our model might offer a good platform to further study the pathological mechanisms, to identify early biomarkers, and also for drug testing studies in AD.

Brain-Computer Interface with Inhibitory Neurons Reveals Subtype-Specific Strategies.

  • Mitani A
  • Curr. Biol.
  • 2018 Jan 8

Literature context:


Abstract:

Brain-computer interfaces have seen an increase in popularity due to their potential for direct neuroprosthetic applications for amputees and disabled individuals. Supporting this promise, animals-including humans-can learn even arbitrary mapping between the activity of cortical neurons and movement of prosthetic devices [1-4]. However, the performance of neuroprosthetic device control has been nowhere near that of limb control in healthy individuals, presenting a dire need to improve the performance. One potential limitation is the fact that previous work has not distinguished diverse cell types in the neocortex, even though different cell types possess distinct functions in cortical computations [5-7] and likely distinct capacities to control brain-computer interfaces. Here, we made a first step in addressing this issue by tracking the plastic changes of three major types of cortical inhibitory neurons (INs) during a neuron-pair operant conditioning task using two-photon imaging of IN subtypes expressing GCaMP6f. Mice were rewarded when the activity of the positive target neuron (N+) exceeded that of the negative target neuron (N-) beyond a set threshold. Mice improved performance with all subtypes, but the strategies were subtype specific. When parvalbumin (PV)-expressing INs were targeted, the activity of N- decreased. However, targeting of somatostatin (SOM)- and vasoactive intestinal peptide (VIP)-expressing INs led to an increase of the N+ activity. These results demonstrate that INs can be individually modulated in a subtype-specific manner and highlight the versatility of neural circuits in adapting to new demands by using cell-type-specific strategies.

Funding information:
  • Biotechnology and Biological Sciences Research Council - P18044(United Kingdom)
  • NEI NIH HHS - P30 EY022589()
  • NEI NIH HHS - R01 EY025349()
  • NIDCD NIH HHS - R01 DC014690()
  • NIDCD NIH HHS - R21 DC012641()
  • NINDS NIH HHS - R01 NS091010()
  • NINDS NIH HHS - U01 NS094342()

Abelson tyrosine-protein kinase 2 regulates myoblast proliferation and controls muscle fiber length.

  • Lee JK
  • Elife
  • 2017 Dec 12

Literature context:


Abstract:

Muscle fiber length is nearly uniform within a muscle but widely different among different muscles. We show that Abelson tyrosine-protein kinase 2 (Abl2) has a key role in regulating myofiber length, as a loss of Abl2 leads to excessively long myofibers in the diaphragm, intercostal and levator auris muscles but not limb muscles. Increased myofiber length is caused by enhanced myoblast proliferation, expanding the pool of myoblasts and leading to increased myoblast fusion. Abl2 acts in myoblasts, but as a consequence of expansion of the diaphragm muscle, the diaphragm central tendon is reduced in size, likely contributing to reduced stamina of Abl2 mutant mice. Ectopic muscle islands, each composed of myofibers of uniform length and orientation, form within the central tendon of Abl2+/- mice. Specialized tendon cells, resembling tendon cells at myotendinous junctions, form at the ends of these muscle islands, suggesting that myofibers induce differentiation of tendon cells, which reciprocally regulate myofiber length and orientation.

Funding information:
  • NIDDK NIH HHS - R01DK080805(United States)
  • NINDS NIH HHS - R01 NS036193()
  • NINDS NIH HHS - R01 NS075124()
  • NINDS NIH HHS - R37 NS036193()

Abrogated Freud-1/Cc2d1a Repression of 5-HT1A Autoreceptors Induces Fluoxetine-Resistant Anxiety/Depression-Like Behavior.

  • Vahid-Ansari F
  • J. Neurosci.
  • 2017 Dec 6

Literature context:


Abstract:

Freud-1/Cc2d1a represses the gene transcription of serotonin-1A (5-HT1A) autoreceptors, which negatively regulate 5-HT tone. To test the role of Freud-1 in vivo, we generated mice with adulthood conditional knock-out of Freud-1 in 5-HT neurons (cF1ko). In cF1ko mice, 5-HT1A autoreceptor protein, binding and hypothermia response were increased, with reduced 5-HT content and neuronal activity in the dorsal raphe. The cF1ko mice displayed increased anxiety- and depression-like behavior that was resistant to chronic antidepressant (fluoxetine) treatment. Using conditional Freud-1/5-HT1A double knock-out (cF1/1A dko) to disrupt both Freud-1 and 5-HT1A genes in 5-HT neurons, no increase in anxiety- or depression-like behavior was seen upon knock-out of Freud-1 on the 5-HT1A autoreceptor-negative background; rather, a reduction in depression-like behavior emerged. These studies implicate transcriptional dysregulation of 5-HT1A autoreceptors by the repressor Freud-1 in anxiety and depression and provide a clinically relevant genetic model of antidepressant resistance. Targeting specific transcription factors, such as Freud-1, to restore transcriptional balance may augment response to antidepressant treatment.SIGNIFICANCE STATEMENT Altered regulation of the 5-HT1A autoreceptor has been implicated in human anxiety, major depression, suicide, and resistance to antidepressants. This study uniquely identifies a single transcription factor, Freud-1, as crucial for 5-HT1A autoreceptor expression in vivo Disruption of Freud-1 in serotonin neurons in mice links upregulation of 5-HT1A autoreceptors to anxiety/depression-like behavior and provides a new model of antidepressant resistance. Treatment strategies to reestablish transcriptional regulation of 5-HT1A autoreceptors could provide a more robust and sustained antidepressant response.

Funding information:
  • NCI NIH HHS - 5P20CA90578(United States)

Distinct Inhibitory Circuits Orchestrate Cortical beta and gamma Band Oscillations.

  • Chen G
  • Neuron
  • 2017 Dec 20

Literature context:


Abstract:

Distinct subtypes of inhibitory interneuron are known to shape diverse rhythmic activities in the cortex, but how they interact to orchestrate specific band activity remains largely unknown. By recording optogenetically tagged interneurons of specific subtypes in the primary visual cortex of behaving mice, we show that spiking of somatostatin (SOM)- and parvalbumin (PV)-expressing interneurons preferentially correlates with cortical beta and gamma band oscillations, respectively. Suppression of SOM cell spiking reduces the spontaneous low-frequency band (<30-Hz) oscillations and selectively reduces visually induced enhancement of beta oscillation. In comparison, suppressing PV cell activity elevates the synchronization of spontaneous activity across a broad frequency range and further precludes visually induced changes in beta and gamma oscillations. Rhythmic activation of SOM and PV cells in the local circuit entrains resonant activity in the narrow 5- to 30-Hz band and the wide 20- to 80-Hz band, respectively. Together, these findings reveal differential and cooperative roles of SOM and PV inhibitory neurons in orchestrating specific cortical oscillations.

Funding information:
  • NCRR NIH HHS - P51RR165(United States)

ESRP1 Mutations Cause Hearing Loss due to Defects in Alternative Splicing that Disrupt Cochlear Development.

  • Rohacek AM
  • Dev. Cell
  • 2017 Nov 6

Literature context:


Abstract:

Alternative splicing contributes to gene expression dynamics in many tissues, yet its role in auditory development remains unclear. We performed whole-exome sequencing in individuals with sensorineural hearing loss (SNHL) and identified pathogenic mutations in Epithelial Splicing-Regulatory Protein 1 (ESRP1). Patient-derived induced pluripotent stem cells showed alternative splicing defects that were restored upon repair of an ESRP1 mutant allele. To determine how ESRP1 mutations cause hearing loss, we evaluated Esrp1-/- mouse embryos and uncovered alterations in cochlear morphogenesis, auditory hair cell differentiation, and cell fate specification. Transcriptome analysis revealed impaired expression and splicing of genes with essential roles in cochlea development and auditory function. Aberrant splicing of Fgfr2 blocked stria vascularis formation due to erroneous ligand usage, which was corrected by reducing Fgf9 gene dosage. These findings implicate mutations in ESRP1 as a cause of SNHL and demonstrate the complex interplay between alternative splicing, inner ear development, and auditory function.

Funding information:
  • NHGRI NIH HHS - U01 HG006546()
  • NIA NIH HHS - R01 AG046544()
  • NIDCD NIH HHS - F31 DC014647()
  • NIDCD NIH HHS - R01 DC006254()
  • NIDCR NIH HHS - R01 DE024749()
  • NIGMS NIH HHS - T32 GM008216()

Melanocyte Stem Cell Activation and Translocation Initiate Cutaneous Melanoma in Response to UV Exposure.

  • Moon H
  • Cell Stem Cell
  • 2017 Nov 2

Literature context:


Abstract:

Melanoma is one of the deadliest cancers, yet the cells of origin and mechanisms of tumor initiation remain unclear. The majority of melanomas emerge from clear skin without a precursor lesion, but it is unknown whether these melanomas can arise from melanocyte stem cells (MCSCs). Here we employ mouse models to define the role of MCSCs as melanoma cells of origin, demonstrate that MCSC quiescence acts as a tumor suppressor, and identify the extrinsic environmental and molecular factors required for the critical early steps of melanoma initiation. Specifically, melanomas originate from melanoma-competent MCSCs upon stimulation by UVB, which induces MCSC activation and translocation via an inflammation-dependent process. Moreover, the chromatin-remodeling factor Hmga2 in the skin plays a critical role in UVB-mediated melanomagenesis. These findings delineate melanoma formation from melanoma-competent MCSCs following extrinsic stimuli, and they suggest that abrogation of Hmga2 function in the microenvironment can suppress MCSC-originating cutaneous melanomas.

The Primate-Specific Gene TMEM14B Marks Outer Radial Glia Cells and Promotes Cortical Expansion and Folding.

  • Liu J
  • Cell Stem Cell
  • 2017 Nov 2

Literature context:


Abstract:

Human brain evolution is associated with expansion and folding of the neocortex. Increased diversity in neural progenitor (NP) populations (such as basally located radial glia [RG], which reside in an enlarged outer subventricular zone [OSVZ]) likely contributes to this evolutionary expansion, although their characteristics and relative contributions are only partially understood. Through single-cell transcriptional profiling of sorted human NP subpopulations, we identified the primate-specific TMEM14B gene as a marker of basal RG. Expression of TMEM14B in embryonic NPs induces cortical thickening and gyrification in postnatal mice. This is accompanied by SVZ expansion, the appearance of outer RG-like cells, and the proliferation of multiple NP subsets, with proportional increases in all cortical layers and normal lamination. TMEM14B drives NP proliferation by increasing the phosphorylation and nuclear translocation of IQGAP1, which in turn promotes G1/S cell cycle transitions. These data show that a single primate-specific gene can drive neurodevelopmental changes that contribute to brain evolution.

Generation of a human control PBMC derived iPS cell line TUSMi001-A from a healthy male donor of Han Chinese genetic background.

  • Wang Y
  • Stem Cell Res
  • 2017 Oct 17

Literature context:


Abstract:

A 59-year old healthy man of Han Chinese genetic background donated his peripheral blood mononuclear cells (PBMC). The non-integrating episomal vector system was used to reprogram his PBMCs with the human OSKM (Oct4, Sox2, Kl4 and c-Myc) transcription factors. The pluripotency of transgene-free iPSCs was confirmed by immunocytochemistry for pluripotency markers and by the ability of the iPSCs to differentiate spontaneously into 3 germ layers in vitro. In addition, the iPSC line displayed a normal karyotype. In the studies of disease mechanism, the iPSC line can be used as a control.

Ubiquitin Linkage-Specific Affimers Reveal Insights into K6-Linked Ubiquitin Signaling.

  • Michel MA
  • Mol. Cell
  • 2017 Oct 5

Literature context:


Abstract:

Several ubiquitin chain types have remained unstudied, mainly because tools and techniques to detect these posttranslational modifications are scarce. Linkage-specific antibodies have shaped our understanding of the roles and dynamics of polyubiquitin signals but are available for only five out of eight linkage types. We here characterize K6- and K33-linkage-specific "affimer" reagents as high-affinity ubiquitin interactors. Crystal structures of affimers bound to their cognate chain types reveal mechanisms of specificity and a K11 cross-reactivity in the K33 affimer. Structure-guided improvements yield superior affinity reagents suitable for western blotting, confocal fluorescence microscopy and pull-down applications. This allowed us to identify RNF144A and RNF144B as E3 ligases that assemble K6-, K11-, and K48-linked polyubiquitin in vitro. A protocol to enrich K6-ubiquitinated proteins from cells identifies HUWE1 as a main E3 ligase for this chain type, and we show that mitofusin-2 is modified with K6-linked polyubiquitin in a HUWE1-dependent manner.

Funding information:
  • European Research Council - 309756()

Age-Dependent Alterations in Meiotic Recombination Cause Chromosome Segregation Errors in Spermatocytes.

  • Zelazowski MJ
  • Cell
  • 2017 Oct 19

Literature context:


Abstract:

Faithful chromosome segregation in meiosis requires crossover (CO) recombination, which is regulated to ensure at least one CO per homolog pair. We investigate the failure to ensure COs in juvenile male mice. By monitoring recombination genome-wide using cytological assays and at hotspots using molecular assays, we show that juvenile mouse spermatocytes have fewer COs relative to adults. Analysis of recombination in the absence of MLH3 provides evidence for greater utilization in juveniles of pathways involving structure-selective nucleases and alternative complexes, which can act upon precursors to generate noncrossovers (NCOs) at the expense of COs. We propose that some designated CO sites fail to mature efficiently in juveniles owing to inappropriate activity of these alternative repair pathways, leading to chromosome mis-segregation. We also find lower MutLγ focus density in juvenile human spermatocytes, suggesting that weaker CO maturation efficiency may explain why younger men have a higher risk of fathering children with Down syndrome.

Establishment of an induced pluripotent stem (iPS) cell line from dermal fibroblasts of an asymptomatic patient with dominant PRPF31 mutation.

  • Terray A
  • Stem Cell Res
  • 2017 Oct 19

Literature context:


Abstract:

A human iPS cell line was generated from fibroblasts of a phenotypically unaffected patient from a family with PRPF31-associated retinitis pigmentosa (RP). The transgene-free iPS cells were generated with the human OSKM transcription factors using the Sendai-virus reprogramming system. iPS cells contained the expected c.709-734dup substitution in exon 8 of PRPF31, expressed the expected pluripotency markers, displayed in vivo differentiation potential to the three germ layers and had normal karyotype. This cellular model will provide a powerful tool to study the unusual pattern of inheritance of PRPF31-associated RP.

A map of human PRDM9 binding provides evidence for novel behaviors of PRDM9 and other zinc-finger proteins in meiosis.

  • Altemose N
  • Elife
  • 2017 Oct 26

Literature context:


Abstract:

PRDM9 binding localizes almost all meiotic recombination sites in humans and mice. However, most PRDM9-bound loci do not become recombination hotspots. To explore factors that affect binding and subsequent recombination outcomes, we mapped human PRDM9 binding sites in a transfected human cell line and measured PRDM9-induced histone modifications. These data reveal varied DNA-binding modalities of PRDM9. We also find that human PRDM9 frequently binds promoters, despite their low recombination rates, and it can activate expression of a small number of genes including CTCFL and VCX. Furthermore, we identify specific sequence motifs that predict consistent, localized meiotic recombination suppression around a subset of PRDM9 binding sites. These motifs strongly associate with KRAB-ZNF protein binding, TRIM28 recruitment, and specific histone modifications. Finally, we demonstrate that, in addition to binding DNA, PRDM9's zinc fingers also mediate its multimerization, and we show that a pair of highly diverged alleles preferentially form homo-multimers.

Funding information:
  • NCRR NIH HHS - S10 RR029731-01(United States)

Aldosterone-Sensing Neurons in the NTS Exhibit State-Dependent Pacemaker Activity and Drive Sodium Appetite via Synergy with Angiotensin II Signaling.

  • Resch JM
  • Neuron
  • 2017 Sep 27

Literature context:


Abstract:

Sodium deficiency increases angiotensin II (ATII) and aldosterone, which synergistically stimulate sodium retention and consumption. Recently, ATII-responsive neurons in the subfornical organ (SFO) and aldosterone-sensitive neurons in the nucleus of the solitary tract (NTSHSD2 neurons) were shown to drive sodium appetite. Here we investigate the basis for NTSHSD2 neuron activation, identify the circuit by which NTSHSD2 neurons drive appetite, and uncover an interaction between the NTSHSD2 circuit and ATII signaling. NTSHSD2 neurons respond to sodium deficiency with spontaneous pacemaker-like activity-the consequence of "cardiac" HCN and Nav1.5 channels. Remarkably, NTSHSD2 neurons are necessary for sodium appetite, and with concurrent ATII signaling their activity is sufficient to produce rapid consumption. Importantly, NTSHSD2 neurons stimulate appetite via projections to the vlBNST, which is also the effector site for ATII-responsive SFO neurons. The interaction between angiotensin signaling and NTSHSD2 neurons provides a neuronal context for the long-standing "synergy hypothesis" of sodium appetite regulation.

Funding information:
  • NIDDK NIH HHS - F32 DK103387()
  • NIDDK NIH HHS - P30 DK046200()
  • NIDDK NIH HHS - P30 DK057521()
  • NIDDK NIH HHS - R01 DK075632()
  • NIDDK NIH HHS - R01 DK089044()
  • NIDDK NIH HHS - R01 DK096010()
  • NIDDK NIH HHS - R01 DK111401()
  • NINDS NIH HHS - K08 NS099425()

Hypothalamic Tuberomammillary Nucleus Neurons: Electrophysiological Diversity and Essential Role in Arousal Stability.

  • Fujita A
  • J. Neurosci.
  • 2017 Sep 27

Literature context:


Abstract:

Histaminergic (HA) neurons, found in the posterior hypothalamic tuberomammillary nucleus (TMN), extend fibers throughout the brain and exert modulatory influence over numerous physiological systems. Multiple lines of evidence suggest that the activity of HA neurons is important in the regulation of vigilance despite the lack of direct, causal evidence demonstrating its requirement for the maintenance of arousal during wakefulness. Given the strong correlation between HA neuron excitability and behavioral arousal, we investigated both the electrophysiological diversity of HA neurons in brain slices and the effect of their acute silencing in vivo in male mice. For this purpose, we first validated a transgenic mouse line expressing cre recombinase in histidine decarboxylase-expressing neurons (Hdc-Cre) followed by a systematic census of the membrane properties of both HA and non-HA neurons in the ventral TMN (TMNv) region. Through unsupervised hierarchical cluster analysis, we found electrophysiological diversity both between TMNv HA and non-HA neurons, and among HA neurons. To directly determine the impact of acute cessation of HA neuron activity on sleep-wake states in awake and behaving mice, we examined the effects of optogenetic silencing of TMNv HA neurons in vivo We found that acute silencing of HA neurons during wakefulness promotes slow-wave sleep, but not rapid eye movement sleep, during a period of low sleep pressure. Together, these data suggest that the tonic firing of HA neurons is necessary for the maintenance of wakefulness, and their silencing not only impairs arousal but is sufficient to rapidly and selectively induce slow-wave sleep.SIGNIFICANCE STATEMENT The function of monoaminergic systems and circuits that regulate sleep and wakefulness is often disrupted as part of the pathophysiology of many neuropsychiatric disorders. One such circuit is the posterior hypothalamic histamine (HA) system, implicated in supporting wakefulness and higher brain function, but has been difficult to selectively manipulate owing to cellular heterogeneity in this region. Here we use a transgenic mouse to interrogate both the characteristic firing properties of HA neurons and their specific role in maintaining wakefulness. Our results demonstrate that the acute, cell type-specific silencing of HA neurons during wakefulness is sufficient to not only impair arousal but to rapidly and selectively induce slow-wave sleep. This work furthers our understanding of HA-mediated mechanisms that regulate behavioral arousal.

Cerebral Vein Malformations Result from Loss of Twist1 Expression and BMP Signaling from Skull Progenitor Cells and Dura.

  • Tischfield MA
  • Dev. Cell
  • 2017 Sep 11

Literature context:


Abstract:

Dural cerebral veins (CV) are required for cerebrospinal fluid reabsorption and brain homeostasis, but mechanisms that regulate their growth and remodeling are unknown. We report molecular and cellular processes that regulate dural CV development in mammals and describe venous malformations in humans with craniosynostosis and TWIST1 mutations that are recapitulated in mouse models. Surprisingly, Twist1 is dispensable in endothelial cells but required for specification of osteoprogenitor cells that differentiate into preosteoblasts that produce bone morphogenetic proteins (BMPs). Inactivation of Bmp2 and Bmp4 in preosteoblasts and periosteal dura causes skull and CV malformations, similar to humans harboring TWIST1 mutations. Notably, arterial development appears normal, suggesting that morphogens from the skull and dura establish optimal venous networks independent from arterial influences. Collectively, our work establishes a paradigm whereby CV malformations result from primary or secondary loss of paracrine BMP signaling from preosteoblasts and dura, highlighting unique cellular interactions that influence tissue-specific angiogenesis in mammals.

Heterophilic Type II Cadherins Are Required for High-Magnitude Synaptic Potentiation in the Hippocampus.

  • Basu R
  • Neuron
  • 2017 Sep 27

Literature context:


Abstract:

Hippocampal CA3 neurons form synapses with CA1 neurons in two layers, stratum oriens (SO) and stratum radiatum (SR). Each layer develops unique synaptic properties but molecular mechanisms that mediate these differences are unknown. Here, we show that SO synapses normally have significantly more mushroom spines and higher-magnitude long-term potentiation (LTP) than SR synapses. Further, we discovered that these differences require the Type II classic cadherins, cadherins-6, -9, and -10. Though cadherins typically function via trans-cellular homophilic interactions, our results suggest presynaptic cadherin-9 binds postsynaptic cadherins-6 and -10 to regulate mushroom spine density and high-magnitude LTP in the SO layer. Loss of these cadherins has no effect on the lower-magnitude LTP typically observed in the SR layer, demonstrating that cadherins-6, -9, and -10 are gatekeepers for high-magnitude LTP. Thus, Type II cadherins may uniquely contribute to the specificity and strength of synaptic changes associated with learning and memory.

Funding information:
  • NEI NIH HHS - R01 EY022073()

Optogenetic Central Amygdala Stimulation Intensifies and Narrows Motivation for Cocaine.

  • Warlow SM
  • J. Neurosci.
  • 2017 Aug 30

Literature context:


Abstract:

Addiction is often characterized by intense motivation for a drug, which may be narrowly focused at the expense of other rewards. Here, we examined the role of amygdala-related circuitry in the amplification and narrowing of motivation focus for intravenous cocaine. We paired optogenetic channelrhodopsin (ChR2) stimulation in either central nucleus of amygdala (CeA) or basolateral amygdala (BLA) of female rats with one particular nose-poke porthole option for earning cocaine infusions (0.3 mg/kg, i.v.). A second alternative porthole earned identical cocaine but without ChR2 stimulation. Consequently, CeA rats quickly came to pursue their CeA ChR2-paired cocaine option intensely and exclusively, elevating cocaine intake while ignoring their alternative cocaine alone option. By comparison, BLA ChR2 pairing failed to enhance cocaine motivation. CeA rats also emitted consummatory bites toward their laser-paired porthole, suggesting that higher incentive salience made that cue more attractive. A separate progressive ratio test of incentive motivation confirmed that CeA ChR2 amplified rats' motivation, raising their breakpoint effort price for cocaine by 10-fold. However, CeA ChR2 laser on its own lacked any reinforcement value: laser by itself was never self-stimulated, not even by the same rats in which it amplified motivation for cocaine. Conversely, CeA inhibition by muscimol/baclofen microinjections prevented acquisition of cocaine self-administration and laser preference, whereas CeA inhibition by optogenetic halorhodopsin suppressed cocaine intake, indicating that CeA circuitry is needed for ordinary cocaine motivation. We conclude that CeA ChR2 excitation paired with a cocaine option specifically focuses and amplifies motivation to produce intense pursuit and consumption focused on that single target.SIGNIFICANCE STATEMENT In addiction, intense incentive motivation often becomes narrowly focused on a particular drug of abuse. Here we show that pairing central nucleus of amygdala (CeA) optogenetic stimulation with one option for earning intravenous cocaine makes that option almost the exclusive focus of intense pursuit and consumption. CeA stimulation also elevated the effort cost rats were willing to pay for cocaine and made associated cues become intensely attractive. However, we also show that CeA laser had no reinforcing properties at all when given alone for the same rats. Therefore, CeA laser pairing makes its associated cocaine option and cues become powerfully attractive in a nearly addictive fashion.

A deficiency of the link protein Bral2 affects the size of the extracellular space in the thalamus of aged mice.

  • Cicanic M
  • J. Neurosci. Res.
  • 2017 Aug 18

Literature context:


Abstract:

Bral2 is a link protein stabilizing the binding between lecticans and hyaluronan in perineuronal nets and axonal coats (ACs) in specific brain regions. Using the real-time iontophoretic method and diffusion-weighted magnetic resonance, we determined the extracellular space (ECS) volume fraction (α), tortuosity (λ), and apparent diffusion coefficient of water (ADCW ) in the thalamic ventral posteromedial nucleus (VPM) and sensorimotor cortex of young adult (3-6 months) and aged (14-20 months) Bral2-deficient (Bral2-/- ) mice and age-matched wild-type (wt) controls. The results were correlated with an analysis of extracellular matrix composition. In the cortex, no changes between wt and Bral2-/- were detected, either in the young or aged mice. In the VPM of aged but not in young Bral2-/- mice, we observed a significant decrease in α and ADCW in comparison with age-matched controls. Bral2 deficiency led to a reduction of both aggrecan- and brevican-associated perineuronal nets and a complete disruption of brevican-based ACs in young as well as aged VPM. Our data suggest that aging is a critical point that reveals the effect of Bral2 deficiency on VPM diffusion. This effect is probably mediated through the enhanced age-related damage of neurons lacking protective ACs, or the exhausting of compensatory mechanisms maintaining unchanged diffusion parameters in young Bral2-/- animals. A decreased ECS volume in aged Bral2-/- mice may influence the diffusion of neuroactive substances, and thus extrasynaptic and also indirectly synaptic transmission in this important nucleus of the somatosensory pathway.

Physiological and pathophysiological control of synaptic GluN2B-NMDA receptors by the C-terminal domain of amyloid precursor protein.

  • Pousinha PA
  • Elife
  • 2017 Jul 6

Literature context:


Abstract:

The amyloid precursor protein (APP) harbors physiological roles at synapses and is central to Alzheimer's disease (AD) pathogenesis. Evidence suggests that APP intracellular domain (AICD) could regulate synapse function, but the underlying molecular mechanisms remain unknown. We addressed AICD actions at synapses, per se, combining in vivo AICD expression, ex vivo AICD delivery or APP knock-down by in utero electroporation of shRNAs with whole-cell electrophysiology. We report a critical physiological role of AICD in controlling GluN2B-containing NMDA receptors (NMDARs) at immature excitatory synapses, via a transcription-dependent mechanism. We further show that AICD increase in mature neurons, as reported in AD, alters synaptic NMDAR composition to an immature-like GluN2B-rich profile. This disrupts synaptic signal integration, via over-activation of SK channels, and synapse plasticity, phenotypes rescued by GluN2B antagonism. We provide a new physiological role for AICD, which becomes pathological upon AICD increase in mature neurons. Thus, AICD could contribute to AD synaptic failure.

Melanopsin expressing human retinal ganglion cells: Subtypes, distribution, and intraretinal connectivity.

  • Hannibal J
  • J. Comp. Neurol.
  • 2017 Jun 1

Literature context:


Abstract:

Intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin belong to a heterogenic population of RGCs which regulate the circadian clock, masking behavior, melatonin suppression, the pupillary light reflex, and sleep/wake cycles. The different functions seem to be associated to different subtypes of melanopsin cells. In rodents, subtype classification has associated subtypes to function. In primate and human retina such classification has so far, not been applied. In the present study using antibodies against N- and C-terminal parts of human melanopsin, confocal microscopy and 3D reconstruction of melanopsin immunoreactive (-ir) RGCs, we applied the criteria used in mouse on human melanopsin-ir RGCs. We identified M1, displaced M1, M2, and M4 cells. We found two other subtypes of melanopsin-ir RGCs, which were named "gigantic M1 (GM1)" and "gigantic displaced M1 (GDM1)." Few M3 cells and no M5 subtypes were labeled. Total cell counts from one male and one female retina revealed that the human retina contains 7283 ± 237 melanopsin-ir (0.63-0.75% of the total number of RGCs). The melanopsin subtypes were unevenly distributed. Most significant was the highest density of M4 cells in the nasal retina. We identified input to the melanopsin-ir RGCs from AII amacrine cells and directly from rod bipolar cells via ribbon synapses in the innermost ON layer of the inner plexiform layer (IPL) and from dopaminergic amacrine cells and GABAergic processes in the outermost OFF layer of the IPL. The study characterizes a heterogenic population of human melanopsin-ir RGCs, which most likely are involved in different functions.

Chronic Loss of CA2 Transmission Leads to Hippocampal Hyperexcitability.

  • Boehringer R
  • Neuron
  • 2017 May 3

Literature context:


Abstract:

Hippocampal CA2 pyramidal cells project into both the neighboring CA1 and CA3 subfields, leaving them well positioned to influence network physiology and information processing for memory and space. While recent work has suggested unique roles for CA2, including encoding position during immobility and generating ripple oscillations, an interventional examination of the integrative functions of these connections has yet to be reported. Here we demonstrate that CA2 recruits feedforward inhibition in CA3 and that chronic genetically engineered shutdown of CA2-pyramidal-cell synaptic transmission consequently results in increased excitability of the recurrent CA3 network. In behaving mice, this led to spatially triggered episodes of network-wide hyperexcitability during exploration accompanied by the emergence of high-frequency discharges during rest. These findings reveal CA2 as a regulator of network processing in hippocampus and suggest that CA2-mediated inhibition in CA3 plays a key role in establishing the dynamic excitatory and inhibitory balance required for proper network function.

Mouse↔rat aggregation chimaeras can develop to adulthood.

  • Bożyk K
  • Dev. Biol.
  • 2017 May 1

Literature context:


Abstract:

In order to examine interactions between cells originating from different species during embryonic development we constructed interspecific mouse↔rat chimaeras by aggregation of 8-cell embryos. Embryos of both species expressed different fluorescent markers (eGFP and DsRed), which enabled us to follow the fate of both components from the moment of aggregation until adulthood. We revealed that in majority of embryos the blastocyst cavity appeared inside the group of rat cells, while the mouse component was allocated to the deeper layer of the inner cell mass and to the polar trophectoderm. However, due to rearrangement of all cells and selective elimination of rat cells, shortly before implantation all primary lineages became chimaeric. Moreover, despite the fact that rat cells were always present in the mural trophectoderm, majority of mouse↔rat chimaeric blastocysts implanted in mouse uterus, and out of those 46% developed into foetuses and pups, half of which were chimaeric. In contrast to mural trophectoderm, polar trophectoderm derivatives, i.e. the placentae of all chimaeras were exclusively of mouse origin. This strongly suggests that the successful postimplantation development of chimaeras is enabled by gradual elimination of xenogeneic cells from the nascent placenta. The size of chimaeric newborns was within the limits of control mouse neonates. The rat component located preferentially in the anterior part of the body, where it contributed mainly to the neural tube. Our observations indicate that although chimaeric animals were able to reach adulthood, high contribution of rat cells tended to diminish their viability.

PPARγ Links BMP2 and TGFβ1 Pathways in Vascular Smooth Muscle Cells, Regulating Cell Proliferation and Glucose Metabolism.

  • Calvier L
  • Cell Metab.
  • 2017 May 2

Literature context:


Abstract:

BMP2 and TGFβ1 are functional antagonists of pathological remodeling in the arteries, heart, and lung; however, the mechanisms in VSMCs, and their disturbance in pulmonary arterial hypertension (PAH), are unclear. We found a pro-proliferative TGFβ1-Stat3-FoxO1 axis in VSMCs, and PPARγ as inhibitory regulator of TGFβ1-Stat3-FoxO1 and TGFβ1-Smad3/4, by physically interacting with Stat3 and Smad3. TGFβ1 induces fibrosis-related genes and miR-130a/301b, suppressing PPARγ. Conversely, PPARγ inhibits TGFβ1-induced mitochondrial activation and VSMC proliferation, and regulates two glucose metabolism-related enzymes, platelet isoform of phosphofructokinase (PFKP, a PPARγ target, via miR-331-5p) and protein phosphatase 1 regulatory subunit 3G (PPP1R3G, a Smad3 target). PPARγ knockdown/deletion in VSMCs activates TGFβ1 signaling. The PPARγ agonist pioglitazone reverses PAH and inhibits the TGFβ1-Stat3-FoxO1 axis in TGFβ1-overexpressing mice. We identified PPARγ as a missing link between BMP2 and TGFβ1 pathways in VSMCs. PPARγ activation can be beneficial in TGFβ1-associated diseases, such as PAH, parenchymal lung diseases, and Marfan's syndrome.

Funding information:
  • NIDDK NIH HHS - R55 DK061935(United States)
  • NIMH NIH HHS - R21 MH098506(United States)

Giardia intestinalis mitosomes undergo synchronized fission but not fusion and are constitutively associated with the endoplasmic reticulum.

  • Voleman L
  • BMC Biol.
  • 2017 Apr 3

Literature context:


Abstract:

BACKGROUND: Mitochondria of opisthokonts undergo permanent fission and fusion throughout the cell cycle. Here, we investigated the dynamics of the mitosomes, the simplest forms of mitochondria, in the anaerobic protist parasite Giardia intestinalis, a member of the Excavata supergroup of eukaryotes. The mitosomes have abandoned typical mitochondrial traits such as the mitochondrial genome and aerobic respiration and their single role known to date is the formation of iron-sulfur clusters. RESULTS: In live experiments, no fusion events were observed between the mitosomes in G. intestinalis. Moreover, the organelles were highly prone to becoming heterogeneous. This suggests that fusion is either much less frequent or even absent in mitosome dynamics. Unlike in mitochondria, division of the mitosomes was absolutely synchronized and limited to mitosis. The association of the nuclear and the mitosomal division persisted during the encystation of the parasite. During the segregation of the divided mitosomes, the subset of the organelles between two G. intestinalis nuclei had a prominent role. Surprisingly, the sole dynamin-related protein of the parasite seemed not to be involved in mitosomal division. However, throughout the cell cycle, mitosomes associated with the endoplasmic reticulum (ER), although none of the known ER-tethering complexes was present. Instead, the ER-mitosome interface was occupied by the lipid metabolism enzyme long-chain acyl-CoA synthetase 4. CONCLUSIONS: This study provides the first report on the dynamics of mitosomes. We show that together with the loss of metabolic complexity of mitochondria, mitosomes of G. intestinalis have uniquely streamlined their dynamics by harmonizing their division with mitosis. We propose that this might be a strategy of G. intestinalis to maintain a stable number of organelles during cell propagation. The lack of mitosomal fusion may also be related to the secondary reduction of the organelles. However, as there are currently no reports on mitochondrial fusion in the whole Excavata supergroup, it is possible that the absence of mitochondrial fusion is an ancestral trait common to all excavates.

Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging.

  • Baar MP
  • Cell
  • 2017 Mar 23

Literature context:


Abstract:

The accumulation of irreparable cellular damage restricts healthspan after acute stress or natural aging. Senescent cells are thought to impair tissue function, and their genetic clearance can delay features of aging. Identifying how senescent cells avoid apoptosis allows for the prospective design of anti-senescence compounds to address whether homeostasis can also be restored. Here, we identify FOXO4 as a pivot in senescent cell viability. We designed a FOXO4 peptide that perturbs the FOXO4 interaction with p53. In senescent cells, this selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis. Under conditions where it was well tolerated in vivo, this FOXO4 peptide neutralized doxorubicin-induced chemotoxicity. Moreover, it restored fitness, fur density, and renal function in both fast aging XpdTTD/TTD and naturally aged mice. Thus, therapeutic targeting of senescent cells is feasible under conditions where loss of health has already occurred, and in doing so tissue homeostasis can effectively be restored.

Funding information:
  • NIA NIH HHS - P01 AG017242()
  • NIA NIH HHS - R37 AG009909()

Hallmarks of Alzheimer's Disease in Stem-Cell-Derived Human Neurons Transplanted into Mouse Brain.

  • Espuny-Camacho I
  • Neuron
  • 2017 Mar 8

Literature context:


Abstract:

Human pluripotent stem cells (PSCs) provide a unique entry to study species-specific aspects of human disorders such as Alzheimer's disease (AD). However, in vitro culture of neurons deprives them of their natural environment. Here we transplanted human PSC-derived cortical neuronal precursors into the brain of a murine AD model. Human neurons differentiate and integrate into the brain, express 3R/4R Tau splice forms, show abnormal phosphorylation and conformational Tau changes, and undergo neurodegeneration. Remarkably, cell death was dissociated from tangle formation in this natural 3D model of AD. Using genome-wide expression analysis, we observed upregulation of genes involved in myelination and downregulation of genes related to memory and cognition, synaptic transmission, and neuron projection. This novel chimeric model for AD displays human-specific pathological features and allows the analysis of different genetic backgrounds and mutations during the course of the disease.

Variability in the number of abdominal leucokinergic neurons in adult Drosophila melanogaster.

  • Alvarez-Rivero J
  • J. Comp. Neurol.
  • 2017 Feb 15

Literature context:


Abstract:

Developmental plasticity allows individuals with the same genotype to show different phenotypes in response to environmental changes. An example of this is how neuronal diversity is protected at the expense of neuronal number under sustained undernourishment during the development of the Drosophila optic lobe. In the development of the Drosophila central nervous system, neuroblasts go through two phases of neurogenesis separated by a period of mitotic quiescence. Although during embryonic development much evidence indicates that both cell number and the cell fates generated by each neuroblast are very precisely controlled in a cell autonomous manner, after quiescence extrinsic factors control the reactivation of neuroblast proliferation in a fashion that has not yet been elucidated. Moreover, there is very little information about whether environmental changes affect lineage progression during postembryonic neurogenesis. Using as a model system the pattern of abdominal leucokinergic neurons (ABLKs), we have analyzed how changes in a set of environmental factors affect the number of ABLKs generated during postembryonic neurogenesis. We describe the variability in ABLK number between individuals and between hemiganglia of the same individual and, by genetic analysis, we identify the bithorax-complex genes and the ecdysone hormone as critical factors in these differences. We also explore the possible adaptive roles involved in this process. J. Comp. Neurol. 525:639-660, 2017. © 2016 Wiley Periodicals, Inc.

Characterization of the Filum terminale as a neural progenitor cell niche in both rats and humans.

  • Chrenek R
  • J. Comp. Neurol.
  • 2017 Feb 15

Literature context:


Abstract:

Neural stem cells (NSCs) reside in a unique microenvironment within the central nervous system (CNS) called the NSC niche. Although they are relatively rare, niches have been previously characterized in both the brain and spinal cord of adult animals. Recently, another potential NSC niche has been identified in the filum terminale (FT), which is a thin band of tissue at the caudal end of the spinal cord. While previous studies have demonstrated that NSCs can be isolated from the FT, the in vivo architecture of this tissue and its relation to other NSC niches in the CNS has not yet been established. In this article we report a histological analysis of the FT NSC niche in postnatal rats and humans. Immunohistochemical characterization reveals that the FT is mitotically active and its cells express similar markers to those in other CNS niches. In addition, the organization of the FT most closely resembles that of the adult spinal cord niche. J. Comp. Neurol. 525:661-675, 2017. © 2016 Wiley Periodicals, Inc.

A Neural Circuit for Auditory Dominance over Visual Perception.

  • Song YH
  • Neuron
  • 2017 Feb 22

Literature context:


Abstract:

When conflicts occur during integration of visual and auditory information, one modality often dominates the other, but the underlying neural circuit mechanism remains unclear. Using auditory-visual discrimination tasks for head-fixed mice, we found that audition dominates vision in a process mediated by interaction between inputs from the primary visual (VC) and auditory (AC) cortices in the posterior parietal cortex (PTLp). Co-activation of the VC and AC suppresses VC-induced PTLp responses, leaving AC-induced responses. Furthermore, parvalbumin-positive (PV+) interneurons in the PTLp mainly receive AC inputs, and muscimol inactivation of the PTLp or optogenetic inhibition of its PV+ neurons abolishes auditory dominance in the resolution of cross-modal sensory conflicts without affecting either sensory perception. Conversely, optogenetic activation of PV+ neurons in the PTLp enhances the auditory dominance. Thus, our results demonstrate that AC input-specific feedforward inhibition of VC inputs in the PTLp is responsible for the auditory dominance during cross-modal integration.

Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis.

  • Ben-Othman N
  • Cell
  • 2017 Jan 12

Literature context:


Abstract:

The recent discovery that genetically modified α cells can regenerate and convert into β-like cells in vivo holds great promise for diabetes research. However, to eventually translate these findings to human, it is crucial to discover compounds with similar activities. Herein, we report the identification of GABA as an inducer of α-to-β-like cell conversion in vivo. This conversion induces α cell replacement mechanisms through the mobilization of duct-lining precursor cells that adopt an α cell identity prior to being converted into β-like cells, solely upon sustained GABA exposure. Importantly, these neo-generated β-like cells are functional and can repeatedly reverse chemically induced diabetes in vivo. Similarly, the treatment of transplanted human islets with GABA results in a loss of α cells and a concomitant increase in β-like cell counts, suggestive of α-to-β-like cell conversion processes also in humans. This newly discovered GABA-induced α cell-mediated β-like cell neogenesis could therefore represent an unprecedented hope toward improved therapies for diabetes.

Funding information:
  • NINDS NIH HHS - NS064013(United States)

Suppression of C9orf72 RNA repeat-induced neurotoxicity by the ALS-associated RNA-binding protein Zfp106.

  • Celona B
  • Elife
  • 2017 Jan 10

Literature context:


Abstract:

Expanded GGGGCC repeats in the first intron of the C9orf72 gene represent the most common cause of familial amyotrophic lateral sclerosis (ALS), but the mechanisms underlying repeat-induced disease remain incompletely resolved. One proposed gain-of-function mechanism is that repeat-containing RNA forms aggregates that sequester RNA binding proteins, leading to altered RNA metabolism in motor neurons. Here, we identify the zinc finger protein Zfp106 as a specific GGGGCC RNA repeat-binding protein, and using affinity purification-mass spectrometry, we show that Zfp106 interacts with multiple other RNA binding proteins, including the ALS-associated factors TDP-43 and FUS. We also show that Zfp106 knockout mice develop severe motor neuron degeneration, which can be suppressed by transgenic restoration of Zfp106 specifically in motor neurons. Finally, we show that Zfp106 potently suppresses neurotoxicity in a Drosophila model of C9orf72 ALS. Thus, these studies identify Zfp106 as an RNA binding protein with important implications for ALS.

Funding information:
  • BLRD VA - I01 BX001108()
  • NHLBI NIH HHS - P01 HL089707()
  • NHLBI NIH HHS - R01 HL064658()
  • NIA NIH HHS - P01 AG019724()
  • NIA NIH HHS - P50 AG023501()
  • NINDS NIH HHS - R01 NS098516()
  • RRD VA - I01 RX002133()

Prohibitin 2 Is an Inner Mitochondrial Membrane Mitophagy Receptor.

  • Wei Y
  • Cell
  • 2017 Jan 12

Literature context:


Abstract:

The removal of unwanted or damaged mitochondria by autophagy, a process called mitophagy, is essential for key events in development, cellular homeostasis, tumor suppression, and prevention of neurodegeneration and aging. However, the precise mechanisms of mitophagy remain uncertain. Here, we identify the inner mitochondrial membrane protein, prohibitin 2 (PHB2), as a crucial mitophagy receptor involved in targeting mitochondria for autophagic degradation. PHB2 binds the autophagosomal membrane-associated protein LC3 through an LC3-interaction region (LIR) domain upon mitochondrial depolarization and proteasome-dependent outer membrane rupture. PHB2 is required for Parkin-induced mitophagy in mammalian cells and for the clearance of paternal mitochondria after embryonic fertilization in C. elegans. Our findings pinpoint a conserved mechanism of eukaryotic mitophagy and demonstrate a function of prohibitin 2 that may underlie its roles in physiology, aging, and disease.

Funding information:
  • NCI NIH HHS - P30 CA142543()
  • NCI NIH HHS - R01 CA109618()
  • NIAID NIH HHS - K08 AI099150()

High-resolution characterization of a PACAP-EGFP transgenic mouse model for mapping PACAP-expressing neurons.

  • Condro MC
  • J. Comp. Neurol.
  • 2016 Dec 15

Literature context:


Abstract:

Pituitary adenylate cyclase-activating polypeptide (PACAP, gene name Adcyap1) regulates a wide variety of neurological and physiological functions, including metabolism and cognition, and plays roles in of multiple forms of stress. Because of its preferential expression in nerve fibers, it has often been difficult to trace and identify the endogenous sources of the peptide in specific populations of neurons. Here, we introduce a transgenic mouse line that harbors in its genome a bacterial artificial chromosome containing an enhanced green fluorescent protein (EGFP) expression cassette inserted upstream of the PACAP ATG translation initiation codon. Analysis of expression in brain sections of these mice using a GFP antibody reveals EGFP expression in distinct neuronal perikarya and dendritic arbors in several major brain regions previously reported to express PACAP from using a variety of approaches, including radioimmunoassay, in situ hybridization, and immunohistochemistry with and without colchicine. EGFP expression in neuronal perikarya was modulated in a manner similar to PACAP gene expression in motor neurons after peripheral axotomy in the ipsilateral facial motor nucleus in the brainstem, providing an example in which the transgene undergoes proper regulation in vivo. These mice and the high-resolution map obtained are expected to be useful in understanding the anatomical patterns of PACAP expression and its plasticity in the mouse. J. Comp. Neurol. 524:3827-3848, 2016. © 2016 Wiley Periodicals, Inc.

Distinct Hippocampal Pathways Mediate Dissociable Roles of Context in Memory Retrieval.

  • Xu C
  • Cell
  • 2016 Nov 3

Literature context:


Abstract:

Memories about sensory experiences are tightly linked to the context in which they were formed. Memory contextualization is fundamental for the selection of appropriate behavioral reactions needed for survival, yet the underlying neuronal circuits are poorly understood. By combining trans-synaptic viral tracing and optogenetic manipulation, we found that the ventral hippocampus (vHC) and the amygdala, two key brain structures encoding context and emotional experiences, interact via multiple parallel pathways. A projection from the vHC to the basal amygdala mediates fear behavior elicited by a conditioned context, whereas a parallel projection from a distinct subset of vHC neurons onto midbrain-projecting neurons in the central amygdala is necessary for context-dependent retrieval of cued fear memories. Our findings demonstrate that two fundamentally distinct roles of context in fear memory retrieval are processed by distinct vHC output pathways, thereby allowing for the formation of robust contextual fear memories while preserving context-dependent behavioral flexibility.

Proteomic Analysis of Unbounded Cellular Compartments: Synaptic Clefts.

  • Loh KH
  • Cell
  • 2016 Aug 25

Literature context:


Abstract:

Cellular compartments that cannot be biochemically isolated are challenging to characterize. Here we demonstrate the proteomic characterization of the synaptic clefts that exist at both excitatory and inhibitory synapses. Normal brain function relies on the careful balance of these opposing neural connections, and understanding how this balance is achieved relies on knowledge of their protein compositions. Using a spatially restricted enzymatic tagging strategy, we mapped the proteomes of two of the most common excitatory and inhibitory synaptic clefts in living neurons. These proteomes reveal dozens of synaptic candidates and assign numerous known synaptic proteins to a specific cleft type. The molecular differentiation of each cleft allowed us to identify Mdga2 as a potential specificity factor influencing Neuroligin-2's recruitment of presynaptic neurotransmitters at inhibitory synapses.

Overexpression of PPARγ specifically in pancreatic β-cells exacerbates obesity-induced glucose intolerance, reduces β-cell mass, and alters islet lipid metabolism in male mice.

  • Hogh KL
  • Endocrinology
  • 2014 Oct 20

Literature context:


Abstract:

The contribution of peroxisomal proliferator-activated receptor (PPAR)-γ agonism in pancreatic β-cells to the antidiabetic actions of thiazolidinediones has not been clearly elucidated. Genetic models of pancreatic β-cell PPARγ ablation have revealed a potential role for PPARγ in β-cell expansion in obesity but a limited role in normal β-cell physiology. Here we overexpressed PPARγ1 or PPARγ2 specifically in pancreatic β-cells of mice subjected to high-fat feeding using an associated adenovirus (β-PPARγ1-HFD and β-PPARγ2-HFD mice). We show β-cell-specific PPARγ1 or PPARγ2 overexpression in diet-induced obese mice exacerbated obesity-induced glucose intolerance with decreased β-cell mass, increased islet cell apoptosis, and decreased plasma insulin compared with obese control mice (β-eGFP-HFD mice). Analysis of islet lipid composition in β-PPARγ2-HFD mice revealed no significant changes in islet triglyceride content and an increase in only one of eight ceramide species measured. Interestingly β-PPARγ2-HFD islets had significantly lower levels of lysophosphatidylcholines, lipid species shown to enhance insulin secretion in β-cells. Gene expression profiling revealed increased expression of uncoupling protein 2 and genes involved in fatty acid transport and β-oxidation. In summary, transgenic overexpression of PPARγ in β-cells in diet-induced obesity negatively impacts whole-animal carbohydrate metabolism associated with altered islet lipid content, increased expression of β-oxidative genes, and reduced β-cell mass.

Funding information:
  • NCI NIH HHS - R01 CA194547(United States)

Activation of angiotensin type 2 receptors partially ameliorates streptozotocin-induced diabetes in male rats by islet protection.

  • Shao C
  • Endocrinology
  • 2014 Mar 25

Literature context:


Abstract:

We have previously demonstrated that rat islets express a high density of angiotensin type 2 receptors and that activation of this receptor evokes insulinotropic effect. In this study, we evaluated the protective effects of Compound 21 (C21), a nonpeptide angiotensin type 2 receptor agonist, on islets in streptozotocin (STZ)-induced diabetes. Rats were assigned to five groups: normal, STZ, and STZ plus C21 (0.24, 0.48, and 0.96 mg/kg·d). C21 was continually infused by a sc implanted osmotic minipump for 14 days, and STZ was bolus injected on day 7. Body weight, water intake, urine excretion, and blood glucose were monitored daily. On the last day, the rats received an oral glucose tolerance test, and the pancreata were saved to examine islet morphology and biochemical parameters of oxidative stress and apoptosis. We found that, compared with control STZ rats, C21-treated STZ rats displayed less water intake and urine excretion, lower blood glucose, higher serum insulin concentration, and improved glucose tolerance. These rats had more islets, larger islet mass, and up-regulated insulin protein and proinsulin 2 mRNA expressions in the pancreas. Their islets displayed lower superoxide, decreased gp91 expression, and increased superoxide dismutase 1 expression as well as less apoptosis and down-regulated caspase-3 expression. In the epididymal adipose tissue of these rats, we found a decreased adipocyte size and up-regulated adipocyte protein 2 expression. The protective effects of C21 on β-cells against the toxic effects of STZ were also confirmed in cultured INS-1E cells. These data suggest that C21 ameliorates STZ-induced diabetes by protecting pancreatic islets via antioxidative and antiapoptotic effects.

Funding information:
  • NIMH NIH HHS - U54 MH084690(United States)

Cholinergic neurons excite cortically projecting basal forebrain GABAergic neurons.

  • Yang C
  • J. Neurosci.
  • 2014 Feb 19

Literature context:


Abstract:

The basal forebrain (BF) plays an important role in the control of cortical activation and attention. Understanding the modulation of BF neuronal activity is a prerequisite to treat disorders of cortical activation involving BF dysfunction, such as Alzheimer's disease. Here we reveal the interaction between cholinergic neurons and cortically projecting BF GABAergic neurons using immunohistochemistry and whole-cell recordings in vitro. In GAD67-GFP knock-in mice, BF cholinergic (choline acetyltransferase-positive) neurons were intermingled with GABAergic (GFP(+)) neurons. Immunohistochemistry for the vesicular acetylcholine transporter showed that cholinergic fibers apposed putative cortically projecting GABAergic neurons containing parvalbumin (PV). In coronal BF slices from GAD67-GFP knock-in or PV-tdTomato mice, pharmacological activation of cholinergic receptors with bath application of carbachol increased the firing rate of large (>20 μm diameter) BF GFP(+) and PV (tdTomato+) neurons, which exhibited the intrinsic membrane properties of cortically projecting neurons. The excitatory effect of carbachol was blocked by antagonists of M1 and M3 muscarinic receptors in two subpopulations of BF GABAergic neurons [large hyperpolarization-activated cation current (Ih) and small Ih, respectively]. Ion substitution experiments and reversal potential measurements suggested that the carbachol-induced inward current was mediated mainly by sodium-permeable cation channels. Carbachol also increased the frequency of spontaneous excitatory and inhibitory synaptic currents. Furthermore, optogenetic stimulation of cholinergic neurons/fibers caused a mecamylamine- and atropine-sensitive inward current in putative GABAergic neurons. Thus, cortically projecting, BF GABAergic/PV neurons are excited by neighboring BF and/or brainstem cholinergic neurons. Loss of cholinergic neurons in Alzheimer's disease may impair cortical activation, in part, through disfacilitation of BF cortically projecting GABAergic/PV neurons.