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On page 1 showing 1 ~ 20 papers out of 43 papers

Platelet-activating factor is a potent pyrogen and cryogen, but it does not mediate lipopolysaccharide fever or hypothermia.

  • Alexandre A Steiner‎ et al.
  • Temperature (Austin, Tex.)‎
  • 2015‎

We examined whether platelet-activating factor (PAF) and its receptor mediate lipopolysaccharide (LPS)-induced fever and hypothermia in rats. Two highly potent, structurally distinct antagonists of the PAF receptor, CV6209 and WEB2086, were used. At a neutral ambient temperature (Ta) of 30ºC, administration of LPS at a low (10 μg/kg, i.v.) or high (1,000 μg/kg, i.v.) dose resulted in fever. The response to the high dose was turned into hypothermia at a subneutral Ta of 22ºC. Neither LPS-induced fever nor hypothermia was affected by pretreatment with CV6209 (5 mg/kg, i.v.) or WEB2086 (5 mg/kg, i.v.). However, both PAF antagonists were efficacious in blocking the thermoregulatory response caused by PAF (334 pmol/kg/min, 1 h, i.v.), regardless of whether the response was a fever (at 30ºC) or hypothermia (at 22ºC). Additional experiments showed that the thermoregulatory responses to LPS and PAF are also distinct in terms of their mediation by prostaglandins. Neither PAF fever nor PAF hypothermia was affected by pretreatment with the cyclooxygenase-2 inhibitor SC236 (5 mg/kg, i.p.), which is known to abrogate LPS fever. The responses to PAF were also unaffected by pretreatment with the cyclooxygenase-1 inhibitor SC560 (5 mg/kg, i.p.), which is known to attenuate LPS hypothermia. In conclusion, PAF infusion at a picomolar dose causes fever at thermoneutrality but hypothermia in a subthermoneutral environment, both responses being dependent on the PAF receptor and independent of prostaglandins. However, the PAF receptor does not mediate LPS-induced fever or hypothermia, thus challenging the dogma that PAF is an upstream mediator of responses to LPS.


Polo-like kinase 1 induces epithelial-to-mesenchymal transition and promotes epithelial cell motility by activating CRAF/ERK signaling.

  • Jianguo Wu‎ et al.
  • eLife‎
  • 2016‎

Polo-like kinase 1 (PLK1) is a key cell cycle regulator implicated in the development of various cancers, including prostate cancer. However, the functions of PLK1 beyond cell cycle regulation remain poorly characterized. Here, we report that PLK1 overexpression in prostate epithelial cells triggers oncogenic transformation. It also results in dramatic transcriptional reprogramming of the cells, leading to epithelial-to-mesenchymal transition (EMT) and stimulation of cell migration and invasion. Consistently, PLK1 downregulation in metastatic prostate cancer cells enhances epithelial characteristics and inhibits cell motility. The signaling mechanisms underlying the observed cellular effects of PLK1 involve direct PLK1-dependent phosphorylation of CRAF with subsequent stimulation of the MEK1/2-ERK1/2-Fra1-ZEB1/2 signaling pathway. Our findings highlight novel non-canonical functions of PLK1 as a key regulator of EMT and cell motility in normal prostate epithelium and prostate cancer. This study also uncovers a previously unanticipated role of PLK1 as a potent activator of MAPK signaling.


Loss of γ-cytoplasmic actin triggers myofibroblast transition of human epithelial cells.

  • Susana Lechuga‎ et al.
  • Molecular biology of the cell‎
  • 2014‎

Transdifferentiation of epithelial cells into mesenchymal cells and myofibroblasts plays an important role in tumor progression and tissue fibrosis. Such epithelial plasticity is accompanied by dramatic reorganizations of the actin cytoskeleton, although mechanisms underlying cytoskeletal effects on epithelial transdifferentiation remain poorly understood. In the present study, we observed that selective siRNA-mediated knockdown of γ-cytoplasmic actin (γ-CYA), but not β-cytoplasmic actin, induced epithelial-to-myofibroblast transition (EMyT) of different epithelial cells. The EMyT manifested by increased expression of α-smooth muscle actin and other contractile proteins, along with inhibition of genes responsible for cell proliferation. Induction of EMyT in γ-CYA-depleted cells depended on activation of serum response factor and its cofactors, myocardial-related transcriptional factors A and B. Loss of γ-CYA stimulated formin-mediated actin polymerization and activation of Rho GTPase, which appear to be essential for EMyT induction. Our findings demonstrate a previously unanticipated, unique role of γ-CYA in regulating epithelial phenotype and suppression of EMyT that may be essential for cell differentiation and tissue fibrosis.


DIPA-family coiled-coils bind conserved isoform-specific head domain of p120-catenin family: potential roles in hydrocephalus and heterotopia.

  • Nicholas O Markham‎ et al.
  • Molecular biology of the cell‎
  • 2014‎

p120-catenin (p120) modulates adherens junction (AJ) dynamics by controlling the stability of classical cadherins. Among all p120 isoforms, p120-3A and p120-1A are the most prevalent. Both stabilize cadherins, but p120-3A is preferred in epithelia, whereas p120-1A takes precedence in neurons, fibroblasts, and macrophages. During epithelial-to-mesenchymal transition, E- to N-cadherin switching coincides with p120-3A to -1A alternative splicing. These isoforms differ by a 101-amino acid "head domain" comprising the p120-1A N-terminus. Although its exact role is unknown, the head domain likely mediates developmental and cancer-associated events linked to p120-1A expression (e.g., motility, invasion, metastasis). Here we identified delta-interacting protein A (DIPA) as the first head domain-specific binding partner and candidate mediator of isoform 1A activity. DIPA colocalizes with AJs in a p120-1A- but not 3A-dependent manner. Moreover, all DIPA family members (Ccdc85a, Ccdc85b/DIPA, and Ccdc85c) interact reciprocally with p120 family members (p120, δ-catenin, p0071, and ARVCF), suggesting significant functional overlap. During zebrafish neural tube development, both knockdown and overexpression of DIPA phenocopy N-cadherin mutations, an effect bearing functional ties to a reported mouse hydrocephalus phenotype associated with Ccdc85c. These studies identify a novel, highly conserved interaction between two protein families that may participate either individually or collectively in N-cadherin-mediated development.


Cold-Induced Thermogenesis and Inflammation-Associated Cold-Seeking Behavior Are Represented by Different Dorsomedial Hypothalamic Sites: A Three-Dimensional Functional Topography Study in Conscious Rats.

  • Samuel P Wanner‎ et al.
  • The Journal of neuroscience : the official journal of the Society for Neuroscience‎
  • 2017‎

In the past, we showed that large electrolytic lesions of the dorsomedial hypothalamus (DMH) promoted hypothermia in cold-exposed restrained rats, but attenuated hypothermia in rats challenged with a high dose of bacterial lipopolysaccharide (LPS) in a thermogradient apparatus. The goal of this study was to identify the thermoeffector mechanisms and DMH representation of the two phenomena and thus to understand how the same lesion could produce two opposite effects on body temperature. We found that the permissive effect of large electrolytic DMH lesions on cold-induced hypothermia was due to suppressed thermogenesis. DMH-lesioned rats also could not develop fever autonomically: they did not increase thermogenesis in response to a low, pyrogenic dose of LPS (10 μg/kg, i.v.). In contrast, changes in thermogenesis were uninvolved in the attenuation of the hypothermic response to a high, shock-inducing dose of LPS (5000 μg/kg, i.v.); this attenuation was due to a blockade of cold-seeking behavior. To compile DMH maps for the autonomic cold defense and for the cold-seeking response to LPS, we studied rats with small thermal lesions in different parts of the DMH. Cold thermogenesis had the highest representation in the dorsal hypothalamic area. Cold seeking was represented by a site at the ventral border of the dorsomedial nucleus. Because LPS causes both fever and hypothermia, we originally thought that the DMH contained a single thermoregulatory site that worked as a fever-hypothermia switch. Instead, we have found two separate sites: one that drives thermogenesis and the other, previously unknown, that drives inflammation-associated cold seeking.SIGNIFICANCE STATEMENT Cold-seeking behavior is a life-saving response that occurs in severe systemic inflammation. We studied this behavior in rats with lesions in the dorsomedial hypothalamus (DMH) challenged with a shock-inducing dose of bacterial endotoxin. We built functional maps of the DMH and found the strongest representation of cold-seeking behavior at the ventral border of the dorsomedial nucleus. We also built maps for cold-induced thermogenesis in unanesthetized rats and found the dorsal hypothalamic area to be its main representation site. Our work identifies the neural substrate of cold-seeking behavior in systemic inflammation and expands the functional topography of the DMH, a structure that modulates autonomic, endocrine, and behavioral responses and is a potential therapeutic target in anxiety and panic disorders.


Coronin 1C negatively regulates cell-matrix adhesion and motility of intestinal epithelial cells.

  • Stanislav N Samarin‎ et al.
  • Biochemical and biophysical research communications‎
  • 2010‎

Coronins, WD-repeat actin-binding proteins, are known to regulate cell motility by coordinating actin filament turnover in lamellipodia of migrating cell. Here we report a novel mechanism of Coronin 1C-mediated cell motility that involves regulation of cell-matrix adhesion. RNAi silencing of Coronin 1C in intestinal epithelial cells enhanced cell migration and modulated lamellipodia dynamics by increasing the persistence of lamellipodial protrusion. Coronin 1C-depleted cells showed increased cell-matrix adhesions and enhanced cell spreading compared to control cells, while over-expression of Coronin 1C antagonized cell adhesion and spreading. Enhanced cell-matrix adhesion of coronin-deficient cells correlated with hyperphosphorylation of focal adhesion kinase (FAK) and paxillin, and an increase in number of focal adhesions and their redistribution at the cell periphery. siRNA depletion of FAK in coronin-deficient cells rescued the effects of Coronin 1C depletion on motility, cell-matrix adhesion, and spreading. Thus, our findings provide the first evidence that Coronin 1C negatively regulates epithelial cell migration via FAK-mediated inhibition of cell-matrix adhesion.


Tumor suppressor scribble regulates assembly of tight junctions in the intestinal epithelium.

  • Andrei I Ivanov‎ et al.
  • The American journal of pathology‎
  • 2010‎

Formation of the epithelial barrier and apico-basal cell polarity represent two characteristics and mutually dependent features of differentiated epithelial monolayers. They are controlled by special adhesive structures, tight junctions (TJs), and polarity protein complexes that define the apical and the basolateral plasma membrane. The functional interplay between TJs and polarity complexes remains poorly understood. We investigated the role of Scribble, a basolateral polarity protein and known tumor suppressor, in regulating TJs in human intestinal epithelium. Scribble was enriched at TJs in T84 and SK-CO15 intestinal epithelial cell monolayers and sections of normal human colonic mucosa. siRNA-mediated knockdown of Scribble in SK-CO15 cells attenuated development of epithelial barrier and inhibited TJ reassembly independently of other basolateral polarity proteins Lgl-1 and Dlg-1. Scribble selectively co-imunoprecipitated with TJ protein ZO-1, and ZO-1 was important for Scribble recruitment to intercellular junctions and TJ reassembly. Lastly, Scribble was mislocalized from TJs and its expression down-regulated in interferon-gamma-treated T84 cell monolayers and inflamed human intestinal mucosa in vivo. We conclude that Scribble is an important regulator of TJ functions and plasticity in the intestinal epithelium. Down-regulation of Scribble may mediate mucosal barrier breakdown during intestinal inflammation.


Non-muscle myosin IIA differentially regulates intestinal epithelial cell restitution and matrix invasion.

  • Brian A Babbin‎ et al.
  • The American journal of pathology‎
  • 2009‎

Epithelial cell motility is critical for self-rejuvenation of normal intestinal mucosa, wound repair, and cancer metastasis. This process is regulated by the reorganization of the F-actin cytoskeleton, which is driven by a myosin II motor. However, the role of myosin II in regulating epithelial cell migration remains poorly understood. This study addressed the role of non-muscle myosin (NM) IIA in two different modes of epithelial cell migration: two-dimensional (2-D) migration that occurs during wound closure and three-dimensional (3-D) migration through a Matrigel matrix that occurs during cancer metastasis. Pharmacological inhibition or siRNA-mediated knockdown of NM IIA in SK-CO15 human colonic epithelial cells resulted in decreased 2-D migration and increased 3-D invasion. The attenuated 2-D migration was associated with increased cell adhesiveness to collagen and laminin and enhanced expression of beta1-integrin and paxillin. On the 2-D surface, NM IIA-deficient SK-CO15 cells failed to assemble focal adhesions and F-actin stress fibers. In contrast, the enhanced invasion of NM IIA-depleted cells was dependent on Raf-ERK1/2 signaling pathway activation, enhanced calpain activity, and increased calpain-2 expression. Our findings suggest that NM IIA promotes 2-D epithelial cell migration but antagonizes 3-D invasion. These observations indicate multiple functions for NM IIA, which, along with the regulation of the F-actin cytoskeleton and cell-matrix adhesions, involve previously unrecognized control of intracellular signaling and protein expression.


Protein kinase C activation disrupts epithelial apical junctions via ROCK-II dependent stimulation of actomyosin contractility.

  • Andrei I Ivanov‎ et al.
  • BMC cell biology‎
  • 2009‎

Disruption of epithelial cell-cell adhesions represents an early and important stage in tumor metastasis. This process can be modeled in vitro by exposing cells to chemical tumor promoters, phorbol esters and octylindolactam-V (OI-V), known to activate protein kinase C (PKC). However, molecular events mediating PKC-dependent disruption of epithelial cell-cell contact remain poorly understood. In the present study we investigate mechanisms by which PKC activation induces disassembly of tight junctions (TJs) and adherens junctions (AJs) in a model pancreatic epithelium.


A unique role for nonmuscle myosin heavy chain IIA in regulation of epithelial apical junctions.

  • Andrei I Ivanov‎ et al.
  • PloS one‎
  • 2007‎

The integrity and function of the epithelial barrier is dependent on the apical junctional complex (AJC) composed of tight and adherens junctions and regulated by the underlying actin filaments. A major F-actin motor, myosin II, was previously implicated in regulation of the AJC, however direct evidence of the involvement of myosin II in AJC dynamics are lacking and the molecular identity of the myosin II motor that regulates formation and disassembly of apical junctions in mammalian epithelia is unknown. We investigated the role of nonmuscle myosin II (NMMII) heavy chain isoforms, A, B, and C in regulation of epithelial AJC dynamics and function. Expression of the three NMMII isoforms was observed in model intestinal epithelial cell lines, where all isoforms accumulated within the perijunctional F-actin belt. siRNA-mediated downregulation of NMMIIA, but not NMMIIB or NMMIIC expression in SK-CO15 colonic epithelial cells resulted in profound changes of cell morphology and cell-cell adhesions. These changes included acquisition of a fibroblast-like cell shape, defective paracellular barrier, and substantial attenuation of the assembly and disassembly of both adherens and tight junctions. Impaired assembly of the AJC observed after NMMIIA knock-down involved dramatic disorganization of perijunctional actin filaments. These findings provide the first direct non-pharmacological evidence of myosin II-dependent regulation of AJC dynamics in mammalian epithelia and highlight a unique role of NMMIIA in junctional biogenesis.


Cellular and molecular bases of the initiation of fever.

  • Alexandre A Steiner‎ et al.
  • PLoS biology‎
  • 2006‎

All phases of lipopolysaccharide (LPS)-induced fever are mediated by prostaglandin (PG) E2. It is known that the second febrile phase (which starts at approximately 1.5 h post-LPS) and subsequent phases are mediated by PGE2 that originated in endotheliocytes and perivascular cells of the brain. However, the location and phenotypes of the cells that produce PGE2 triggering the first febrile phase (which starts at approximately 0.5 h) remain unknown. By studying PGE2 synthesis at the enzymatic level, we found that it was activated in the lung and liver, but not in the brain, at the onset of the first phase of LPS fever in rats. This activation involved phosphorylation of cytosolic phospholipase A2 (cPLA2) and transcriptional up-regulation of cyclooxygenase (COX)-2. The number of cells displaying COX-2 immunoreactivity surged in the lung and liver (but not in the brain) at the onset of fever, and the majority of these cells were identified as macrophages. When PGE2 synthesis in the periphery was activated, the concentration of PGE2 increased both in the venous blood (which collects PGE2 from tissues) and arterial blood (which delivers PGE2 to the brain). Most importantly, neutralization of circulating PGE2 with an anti-PGE2 antibody both delayed and attenuated LPS fever. It is concluded that fever is initiated by circulating PGE2 synthesized by macrophages of the LPS-processing organs (lung and liver) via phosphorylation of cPLA2 and transcriptional up-regulation of COX-2. Whether PGE2 produced at the level of the blood-brain barrier also contributes to the development of the first phase remains to be clarified.


A vesicle trafficking protein αSNAP regulates Paneth cell differentiation in vivo.

  • Susana Lechuga‎ et al.
  • Biochemical and biophysical research communications‎
  • 2017‎

A soluble N-ethylmaleimide-sensitive factor-attachment protein alpha (αSNAP) is a multifunctional scaffolding protein that regulates intracellular vesicle trafficking and signaling. In cultured intestinal epithelial cells, αSNAP has been shown to be essential for cell survival, motility, and adhesion; however, its physiologic functions in the intestinal mucosa remain unknown. In the present study, we used a mouse with a spontaneous hydrocephalus with hop gait (hyh) mutation of αSNAP to examine the roles of this trafficking protein in regulating intestinal epithelial homeostasis in vivo. Homozygous hyh mice demonstrated decreased expression of αSNAP protein in the intestinal epithelium, but did not display gross abnormalities of epithelial architecture in the colon and ileum. Such αSNAP depletion attenuated differentiation of small intestinal epithelial enteroids ex vivo. Furthermore, αSNAP-deficient mutant animals displayed reduced formation of lysozyme granules in small intestinal crypts and decreased expression of lysozyme and defensins in the intestinal mucosa, which is indicative of defects in Paneth cell differentiation. By contrast, development of Goblet cells, enteroendocrine cells, and assembly of enterocyte apical junctions was not altered in hyh mutant mice. Our data revealed a novel role of αSNAP in the intestinal Paneth cell differentiation in vivo.


GSDMB is increased in IBD and regulates epithelial restitution/repair independent of pyroptosis.

  • Nitish Rana‎ et al.
  • Cell‎
  • 2022‎

Gasdermins are a family of structurally related proteins originally described for their role in pyroptosis. Gasdermin B (GSDMB) is currently the least studied, and while its association with genetic susceptibility to chronic mucosal inflammatory disorders is well established, little is known about its functional relevance during active disease states. Herein, we report increased GSDMB in inflammatory bowel disease, with single-cell analysis identifying epithelial specificity to inflamed colonocytes/crypt top colonocytes. Surprisingly, mechanistic experiments and transcriptome profiling reveal lack of inherent GSDMB-dependent pyroptosis in activated epithelial cells and organoids but instead point to increased proliferation and migration during in vitro wound closure, which arrests in GSDMB-deficient cells that display hyper-adhesiveness and enhanced formation of vinculin-based focal adhesions dependent on PDGF-A-mediated FAK phosphorylation. Importantly, carriage of disease-associated GSDMB SNPs confers functional defects, disrupting epithelial restitution/repair, which, altogether, establishes GSDMB as a critical factor for restoration of epithelial barrier function and the resolution of inflammation.


Systemic antibiotic prophylaxis does not affect infectious complications in pediatric burn injury: A meta-analysis.

  • Alexandra Csenkey‎ et al.
  • PloS one‎
  • 2019‎

In pediatric burns the use of systemic antibiotic prophylaxis is a standard procedure in some burn centers, though its beneficial effect on the infectious complications is debated. The present meta-analysis aimed at determining whether systemic antibiotic prophylaxis prevents infectious complications in pediatric patients with burn injuries. We searched the PubMed, EMBASE, and Cochrane Library databases from inception to August 2019. We included 6 studies, in which event rates of infectious complications were reported in children with burn injuries receiving or not receiving systemic antibiotic prophylaxis. We found that the overall odds ratio (OR) of developing an infection (including local and systemic) was not different between the groups (OR = 1.35; 95% CI, 0.44, 4.18). The chances for systemic infectious complications alone were also not different between antibiotic-treated and non-treated patients (OR = 0.74; 95% CI, 0.38, 1.45). Based on the age, affected total body surface area, and country income level, we did not find any subgroup that benefited from the prophylaxis. Our findings provide quantitative evidence for the inefficacy of systemic antibiotic prophylaxis in preventing infections in pediatric burns. To validate our conclusion, multinational, randomized trials in a diverse population of children with burn injuries are warranted.


Anillin regulates breast cancer cell migration, growth, and metastasis by non-canonical mechanisms involving control of cell stemness and differentiation.

  • Dongdong Wang‎ et al.
  • Breast cancer research : BCR‎
  • 2020‎

Breast cancer metastasis is driven by a profound remodeling of the cytoskeleton that enables efficient cell migration and invasion. Anillin is a unique scaffolding protein regulating major cytoskeletal structures, such as actin filaments, microtubules, and septin polymers. It is markedly overexpressed in breast cancer, and high anillin expression is associated with poor prognosis. The aim of this study was to investigate the role of anillin in breast cancer cell migration, growth, and metastasis.


Mechanism of internalization of MDA-7/IL-24 protein and its cognate receptors following ligand-receptor docking.

  • Anjan K Pradhan‎ et al.
  • Oncotarget‎
  • 2019‎

Melanoma differentiation associated gene-7 (mda-7/IL-24) is a member of the IL-10 family of cytokines, with ubiquitous direct and "bystander" tumor-selective killing properties. MDA-7/IL-24 protein binds distinct type II cytokine heterodimeric receptor complexes, IL-20R1/IL-20R2, IL-22R1/IL-20R1 and IL-22R1/IL-20R2. Recombinant MDA-7/IL-24 protein induces endogenous mda-7/IL-24 expression in a receptor-dependent manner; since A549 cells that lack a complete set of cognate receptors are not responsive to exogenous protein. The mechanism of MDA-7/IL-24 ligand-receptor biology is not well understood. We explored the interaction of MDA-7/IL-24 with its' receptors and the consequences of ligand-receptor docking. Using both pharmacological and genetic approaches we demonstrate that MDA-7/IL-24 internalization employs the clathrin-mediated endocytic pathway leading to degradation of receptors via the lysosomal/ubiquitin proteosomal pathway. This clathrin-mediated endocytosis is dynamin-dependent. This study resolves a novel mechanism of MDA-7/IL-24 protein "bystander" function, which involves receptor/protein-mediated internalization and receptor degradation.


Neural substrate of cold-seeking behavior in endotoxin shock.

  • Maria C Almeida‎ et al.
  • PloS one‎
  • 2006‎

Systemic inflammation is a leading cause of hospital death. Mild systemic inflammation is accompanied by warmth-seeking behavior (and fever), whereas severe inflammation is associated with cold-seeking behavior (and hypothermia). Both behaviors are adaptive. Which brain structures mediate which behavior is unknown. The involvement of hypothalamic structures, namely, the preoptic area (POA), paraventricular nucleus (PVH), or dorsomedial nucleus (DMH), in thermoregulatory behaviors associated with endotoxin (lipopolysaccharide [LPS])-induced systemic inflammation was studied in rats. The rats were allowed to select their thermal environment by freely moving in a thermogradient apparatus. A low intravenous dose of Escherichia coli LPS (10 microg/kg) caused warmth-seeking behavior, whereas a high, shock-inducing dose (5,000 microg/kg) caused cold-seeking behavior. Bilateral electrocoagulation of the PVH or DMH, but not of the POA, prevented this cold-seeking response. Lesioning the DMH with ibotenic acid, an excitotoxin that destroys neuronal bodies but spares fibers of passage, also prevented LPS-induced cold-seeking behavior; lesioning the PVH with ibotenate did not affect it. Lesion of no structure affected cold-seeking behavior induced by heat exposure or by pharmacological stimulation of the transient receptor potential (TRP) vanilloid-1 channel ("warmth receptor"). Nor did any lesion affect warmth-seeking behavior induced by a low dose of LPS, cold exposure, or pharmacological stimulation of the TRP melastatin-8 ("cold receptor"). We conclude that LPS-induced cold-seeking response is mediated by neuronal bodies located in the DMH and neural fibers passing through the PVH. These are the first two landmarks on the map of the circuitry of cold-seeking behavior associated with endotoxin shock.


Microtubules regulate disassembly of epithelial apical junctions.

  • Andrei I Ivanov‎ et al.
  • BMC cell biology‎
  • 2006‎

Epithelial tight junction (TJ) and adherens junction (AJ) form the apical junctional complex (AJC) which regulates cell-cell adhesion, paracellular permeability and cell polarity. The AJC is anchored on cytoskeletal structures including actin microfilaments and microtubules. Such cytoskeletal interactions are thought to be important for the assembly and remodeling of apical junctions. In the present study, we investigated the role of microtubules in disassembly of the AJC in intestinal epithelial cells using a model of extracellular calcium depletion.


The Gain-of-Function Integrin β3 Pro33 Variant Alters the Serotonin System in the Mouse Brain.

  • Michael R Dohn‎ et al.
  • The Journal of neuroscience : the official journal of the Society for Neuroscience‎
  • 2017‎

Engagement of integrins by the extracellular matrix initiates signaling cascades that drive a variety of cellular functions, including neuronal migration and axonal pathfinding in the brain. Multiple lines of evidence link the ITGB3 gene encoding the integrin β3 subunit with the serotonin (5-HT) system, likely via its modulation of the 5-HT transporter (SERT). The ITGB3 coding polymorphism Leu33Pro (rs5918, PlA2) produces hyperactive αvβ3 receptors that influence whole-blood 5-HT levels and may influence the risk for autism spectrum disorder (ASD). Using a phenome-wide scan of psychiatric diagnoses, we found significant, male-specific associations between the Pro33 allele and attention-deficit hyperactivity disorder and ASDs. Here, we used knock-in (KI) mice expressing an Itgb3 variant that phenocopies the human Pro33 variant to elucidate the consequences of constitutively enhanced αvβ3 signaling to the 5-HT system in the brain. KI mice displayed deficits in multiple behaviors, including anxiety, repetitive, and social behaviors. Anatomical studies revealed a significant decrease in 5-HT synapses in the midbrain, accompanied by decreases in SERT activity and reduced localization of SERTs to integrin adhesion complexes in synapses of KI mice. Inhibition of focal adhesion kinase (FAK) rescued SERT function in synapses of KI mice, demonstrating that constitutive active FAK signaling downstream of the Pro32Pro33 integrin αvβ3 suppresses SERT activity. Our studies identify a complex regulation of 5-HT homeostasis and behaviors by integrin αvβ3, revealing an important role for integrins in modulating risk for neuropsychiatric disorders.SIGNIFICANCE STATEMENT The integrin β3 Leu33Pro coding polymorphism has been associated with autism spectrum disorders (ASDs) within a subgroup of patients with elevated blood 5-HT levels, linking integrin β3, 5-HT, and ASD risk. We capitalized on these interactions to demonstrate that the Pro33 coding variation in the murine integrin β3 recapitulates the sex-dependent neurochemical and behavioral attributes of ASD. Using state-of-the-art techniques, we show that presynaptic 5-HT function is altered in these mice, and that the localization of 5-HT transporters to specific compartments within the synapse, disrupted by the integrin β3 Pro33 mutation, is critical for appropriate reuptake of 5-HT. Our studies provide fundamental insight into the genetic network regulating 5-HT neurotransmission in the CNS that is also associated with ASD risk.


Adducins inhibit lung cancer cell migration through mechanisms involving regulation of cell-matrix adhesion and cadherin-11 expression.

  • Susana Lechuga‎ et al.
  • Biochimica et biophysica acta. Molecular cell research‎
  • 2019‎

Cell migration is a critical mechanism controlling tissue morphogenesis, epithelial wound healing and tumor metastasis. Migrating cells depend on orchestrated remodeling of the plasma membrane and the underlying actin cytoskeleton, which is regulated by the spectrin-adducin-based membrane skeleton. Expression of adducins is altered during tumorigenesis, however, their involvement in metastatic dissemination of tumor cells remains poorly characterized. This study investigated the roles of α-adducin (ADD1) and γ-adducin (ADD3) in regulating migration and invasion of non-small cell lung cancer (NSCLC) cells. ADD1 was mislocalized, whereas ADD3 was markedly downregulated in NSCLC cells with the invasive mesenchymal phenotype. CRISPR/Cas9-mediated knockout of ADD1 and ADD3 in epithelial-type NSCLC and normal bronchial epithelial cells promoted their Boyden chamber migration and Matrigel invasion. Furthermore, overexpression of ADD1, but not ADD3, in mesenchymal-type NSCLC cells decreased cell migration and invasion. ADD1-overexpressing NSCLC cells demonstrated increased adhesion to the extracellular matrix (ECM), accompanied by enhanced assembly of focal adhesions and hyperphosphorylation of Src and paxillin. The increased adhesiveness and decreased motility of ADD1-overexpressing cells were reversed by siRNA-mediated knockdown of Src. By contrast, the accelerated migration of ADD1 and ADD3-depleted NSCLC cells was ECM adhesion-independent and was driven by the upregulated expression of pro-motile cadherin-11. Overall, our findings reveal a novel function of adducins as negative regulators of NSCLC cell migration and invasion, which could be essential for limiting lung cancer progression and metastasis.


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