Literature context: pore Cat# AB_2253 Lot# 2828588 RRID:AB_1586992), anti-BrdU (Abcam Cat# ab6326
BACKGROUND AND PURPOSE: The cannabinoid system exerts functional regulation of neural stem cell (NSC) proliferation and adult neurogenesis, yet not all effects of cannabinoid-like compounds seen can be attributed to the cannabinoid 1 (CB1 ) or CB2 receptor. The recently de-orphaned GPR55 has been shown to be activated by numerous cannabinoid ligands suggesting that GPR55 is a third cannabinoid receptor. Here, we examined the role of GPR55 activation in NSC proliferation and early adult neurogenesis. EXPERIMENTAL APPROACH: The effects of GPR55 agonists (LPI, O-1602, ML184) on human (h) NSC proliferation in vitro were assessed by flow cytometry. Human NSC differentiation was determined by flow cytometry, qPCR and immunohistochemistry. Immature neuron formation in the hippocampus of C57BL/6 and GPR55-/- mice was evaluated by immunohistochemistry. KEY RESULTS: Activation of GPR55 significantly increased proliferation rates of hNSCs in vitro. These effects were attenuated by ML193, a selective GPR55 antagonist. ML184 significantly promoted neuronal differentiation in vitro while ML193 reduced differentiation rates as compared to vehicle treatment. Continuous administration of O-1602 into the hippocampus via a cannula connected to an osmotic pump resulted in increased Ki67+ cells within the dentate gyrus. O-1602 increased immature neuron generation, as assessed by DCX+ and BrdU+ cells, as compared to vehicle-treated animals. GPR55-/- animals displayed reduced rates of proliferation and neurogenesis within the hippocampus while O-1602 had no effect as compared to vehicle controls. CONCLUSIONS AND IMPLICATIONS: Together, these findings suggest GPR55 activation as a novel target and strategy to regulate NSC proliferation and adult neurogenesis.
Literature context: 1:1000: Millipore Cat# AB_2253, RRID:AB_1586992) in blocking solution at 4Â°C ov
Facial vibrissae, commonly known as whiskers, are the main sensitive tactile system in rodents. Whisker stimulation triggers neuronal activity that promotes neural plasticity in the barrel cortex (BC) and helps create spatial maps in the adult hippocampus. Moreover, activity-dependent inputs and calcium homeostasis modulate adult neurogenesis. Therefore, the neuronal activity of the BC possibly regulates hippocampal functions and neurogenesis. To assess whether tactile information from facial whiskers may modulate hippocampal functions and neurogenesis, we permanently eliminated whiskers in CD1 male mice and analyzed the effects in cellular composition, molecular expression and memory processing in the adult hippocampus. Our data indicated that the permanent deprivation of whiskers reduced in 4-fold the density of c-Fos+ cells (a calcium-dependent immediate early gene) in cornu ammonis subfields (CA1, CA2 and CA3) and 4.5-fold the dentate gyrus (DG). A significant reduction in the expression of calcium-binding proteincalbindin-D28k was also observed in granule cells of the DG. Notably, these changes coincided with an increase in apoptosis and a decrease in the proliferation of neural precursor cells in the DG, which ultimately reduced the number of Bromodeoxyuridine (BrdU)+NeuN+ mature neurons generated after whisker elimination. These abnormalities in the hippocampus were associated with a significant impairment of spatial memory and navigation skills. This is the first evidence indicating that tactile inputs from vibrissal follicles strongly modify the expression of c-Fos and calbindin in the DG, disrupt different aspects of hippocampal neurogenesis, and support the notion that spatial memory and navigation skills strongly require tactile information in the hippocampus.
Literature context: ; 1:100 Millipore; Cat# AB_2253 RRID:AB_1586992). The secondary antibodies were
Traumatic brain injury (TBI) leads to cellular loss, destabilisation of membranes, disruption of synapses and altered brain connectivity, and increased risk of neurodegenerative disease. A significant and long-lasting decrease in phospholipids (PL), essential membrane constituents, has recently been reported in plasma and brain tissue, in human and experimental TBI. We hypothesised that supporting PL synthesis post-injury could improve outcome after TBI. We tested this hypothesis using a multi-nutrient combination designed to support the biosynthesis of phospholipids and available for clinical use. The multi-nutrient Fortasyn® Connect (FC) contains polyunsaturated omega-3 fatty acids, choline, uridine, vitamins, co-factors required for PL biosynthesis, and has been shown to have significant beneficial effects in early Alzheimer's disease. Male C57BL/6 mice received a controlled cortical impact injury and then were fed a control diet or a diet enriched with FC for 70 days. FC led to a significantly improved sensorimotor outcome and cognition, reduced lesion size and oligodendrocyte loss, and it restored myelin. It reversed the loss of the synaptic protein synaptophysin and decreased levels of the axon growth inhibitor Nogo-A, thus creating a permissive environment. It decreased microglia activation and the rise in ß-amyloid precursor protein and restored the depressed neurogenesis. The effects of this medical multi-nutrient suggest that support of PL biosynthesis after TBI, a new treatment paradigm, has significant therapeutic potential in this neurological condition for which there is no satisfactory treatment. The multi-nutrient tested has been used in dementia patients, is safe and well-tolerated, which would enable rapid clinical exploration in TBI.
Literature context: llipore Cat# AB_2253 RRID:AB_1586992 Rabbit anti-NeuN Millipore Cat#
Adult hippocampal neurogenesis declines in aging rodents and primates. Aging humans are thought to exhibit waning neurogenesis and exercise-induced angiogenesis, with a resulting volumetric decrease in the neurogenic hippocampal dentate gyrus (DG) region, although concurrent changes in these parameters are not well studied. Here we assessed whole autopsy hippocampi from healthy human individuals ranging from 14 to 79 years of age. We found similar numbers of intermediate neural progenitors and thousands of immature neurons in the DG, comparable numbers of glia and mature granule neurons, and equivalent DG volume across ages. Nevertheless, older individuals have less angiogenesis and neuroplasticity and a smaller quiescent progenitor pool in anterior-mid DG, with no changes in posterior DG. Thus, healthy older subjects without cognitive impairment, neuropsychiatric disease, or treatment display preserved neurogenesis. It is possible that ongoing hippocampal neurogenesis sustains human-specific cognitive function throughout life and that declines may be linked to compromised cognitive-emotional resilience.
Literature context: in (DCX) (1:300; EMD-Millipore, RRID:AB_2253), and rabbit anti-synapsin-1 (1
Cell surface neural adhesion proteins are critical components in the complex orchestration of cell proliferation, apoptosis, and neuritogenesis essential for proper brain construction and behavior. We focused on the impact of two plasticity-associated IgLON family neural adhesion molecules, Neurotrimin (Ntm) and Limbic system associated membrane protein (Lsamp), on mouse behavior and its underlying neural development. Phenotyping neurons derived from the hippocampi of Lsamp-/-, Ntm-/- and Lsamp-/-Ntm-/- mice was performed in parallel with behavioral testing. While the anatomy of mutant brains revealed no gross changes, the Ntm-/- hippocampal neurons exhibited premature sprouting of neurites and manifested accelerated neurite elongation and branching. We propose that Ntm exerts an inhibitory impact on neurite outgrowth, whereas Lsamp appears to be an enhancer of the said process as premature neuritogenesis in Ntm-/- neurons is apparent only in the presence of Lsamp. We also show interplay between Lsamp and Ntm in regulating tissue homeostasis: the impact of Ntm on cellular proliferation was dependent on Lsamp, and Lsamp appeared to be a positive regulator of apoptosis in the presence of Ntm. Behavioral phenotyping indicated test-specific interactions between Lsamp and Ntm. The phenotypes of single mutant lines, such as reduced swimming speed in Morris water maze and increased activity in the elevated plus maze, were magnified in Lsamp-/-Ntm-/- mice. Altogether, evidence both from behavioral experiments and cultured hippocampal cells show combined and differential interactions between Ntm and Lsamp in the formation of hippocampal circuits and behavioral profiles. We demonstrate that mutual interactions between IgLON molecules regulate the initiation of neurite sprouting at very early ages, and even cell-autonomously, independent of their regulation of cell-cell adhesion.
Literature context: in (RRID:AB_1586992) were obtained from Millipore,
Adult hippocampal neurogenesis has been shown to be required for certain types of cognitive function. For example, studies have shown that these neurons are critical for pattern separation, the ability to store similar experiences as distinct memories. Although traumatic brain injury (TBI) has been shown to cause the loss of newborn hippocampal neurons, the signaling pathway(s) that triggers their death is unknown. Endoplasmic reticulum (ER) stress activates the PERK-eIF2α pathway that acts to restore ER function and improve cell survival. However, unresolved/intense ER stress activates C/EBP homologous protein (CHOP), leading to cell death. We show that TBI causes the death of hippocampal newborn neurons via CHOP. Using CHOP KO mice, we show that loss of CHOP markedly reduces newborn neuron loss after TBI. Injured CHOP mice performed significantly better in a context fear discrimination task compared with injured wild-type mice. In contrast, the PERK inhibitor GSK2606414 exacerbated doublecortin cell loss and worsened contextual discrimination. Administration of guanabenz (which reduces ER stress) to injured male rats reduced the loss of newborn neurons and improved one-trial contextual fear memory. Interestingly, we also found that the surviving newborn neurons in brain-injured animals had dendritic loss, which was not observed in injured CHOP KO mice or in animals treated with guanabenz. These results indicate that ER stress plays a key role in the death of newborn neurons after TBI. Further, these findings indicate that ER stress can alter dendritic arbors, suggesting a role for ER stress in neuroplasticity and dendritic pathologies.SIGNIFICANCE STATEMENT The hippocampus, a structure in the temporal lobe, is critical for learning and memory. The hippocampus is one of only two areas in which neurons are generated in the adult brain. These newborn neurons are required for certain types of memory, and are particularly vulnerable to traumatic brain injury (TBI). However, the mechanism(s) that causes the loss of these cells after TBI is poorly understood. We show that endoplasmic reticulum (ER) stress pathways are activated in newborn neurons after TBI, and that manipulation of the CHOP cascade improves newborn neuron survival and cognitive outcome. These results suggest that treatments that prevent/resolve ER stress may be beneficial in treating TBI-triggered memory dysfunction.
Literature context: llipore Cat# AB_2253; RRID:AB_1586992 rabbit anti-BrdU Abcam Cat# ab6
Somatic stem cells have been identified in multiple adult tissues. Whether self-renewal occurs symmetrically or asymmetrically is key to understanding long-term stem cell maintenance and generation of progeny for cell replacement. In the adult mouse brain, neural stem cells (NSCs) (B1 cells) are retained in the walls of the lateral ventricles (ventricular-subventricular zone [V-SVZ]). The mechanism of B1 cell retention into adulthood for lifelong neurogenesis is unknown. Using multiple clonal labeling techniques, we show that the vast majority of B1 cells divide symmetrically. Whereas 20%-30% symmetrically self-renew and can remain in the niche for several months before generating neurons, 70%-80% undergo consuming divisions generating progeny, resulting in the depletion of B1 cells over time. This cellular mechanism decouples self-renewal from the generation of progeny. Limited rounds of symmetric self-renewal and consuming symmetric differentiation divisions can explain the levels of neurogenesis observed throughout life.
Literature context: lecortin Millipore Cat#AB_2253; RRID:AB_1586992 Goat polyclonal anti-Doublecort
Radial glia (RG) are embryonic neural stem cells (NSCs) that produce neuroblasts and provide fibers that act as a scaffold for neuroblast migration during embryonic development. Although they normally disappear soon after birth, here we found that RG fibers can persist in injured neonatal mouse brains and act as a scaffold for postnatal ventricular-subventricular zone (V-SVZ)-derived neuroblasts that migrate to the lesion site. This injury-induced maintenance of RG fibers has a limited time window during post-natal development and promotes directional saltatory movement of neuroblasts via N-cadherin-mediated cell-cell contacts that promote RhoA activation. Transplanting an N-cadherin-containing scaffold into injured neonatal brains likewise promotes migration and maturation of V-SVZ-derived neuroblasts, leading to functional improvements in impaired gait behaviors. Together these results suggest that RG fibers enable postnatal V-SVZ-derived neuroblasts to migrate toward sites of injury, thereby enhancing neuronal regeneration and functional recovery from neonatal brain injuries.
Literature context: (1:3000, Millipore, RRID:AB_1586992), rabbit anti-Er81 (1:1000) (Ar
The intercalated cells (ITCs) of the amygdala have been shown to be critical regulatory components of amygdalar circuits, which control appropriate fear responses. Despite this, the molecular processes guiding ITC development remain poorly understood. Here we establish the zinc finger transcription factor Tshz1 as a marker of ITCs during their migration from the dorsal lateral ganglionic eminence through maturity. Using germline and conditional knock-out (cKO) mouse models, we show that Tshz1 is required for the proper migration and differentiation of ITCs. In the absence of Tshz1, migrating ITC precursors fail to settle in their stereotypical locations encapsulating the lateral amygdala and BLA. Furthermore, they display reductions in the ITC marker Foxp2 and ectopic persistence of the dorsal lateral ganglionic eminence marker Sp8. Tshz1 mutant ITCs show increased cell death at postnatal time points, leading to a dramatic reduction by 3 weeks of age. In line with this, Foxp2-null mutants also show a loss of ITCs at postnatal time points, suggesting that Foxp2 may function downstream of Tshz1 in the maintenance of ITCs. Behavioral analysis of male Tshz1 cKOs revealed defects in fear extinction as well as an increase in floating during the forced swim test, indicative of a depression-like phenotype. Moreover, Tshz1 cKOs display significantly impaired social interaction (i.e., increased passivity) regardless of partner genetics. Together, these results suggest that Tshz1 plays a critical role in the development of ITCs and that fear, depression-like and social behavioral deficits arise in their absence.SIGNIFICANCE STATEMENT We show here that the zinc finger transcription factor Tshz1 is expressed during development of the intercalated cells (ITCs) within the mouse amygdala. These neurons have previously been shown to play a crucial role in fear extinction. Tshz1 mouse mutants exhibit severely reduced numbers of ITCs as a result of abnormal migration, differentiation, and survival of these neurons. Furthermore, the loss of ITCs in mouse Tshz1 mutants correlates well with defects in fear extinction as well as the appearance of depression-like and abnormal social interaction behaviors reminiscent of depressive disorders observed in human patients with distal 18q deletions, including the Tshz1 locus.
Literature context: #AB2253, RRID:AB_1586992), or 1:400
Epileptic seizures potently modulate hippocampal adult neurogenesis, and adult-born dentate granule cells contribute to the pathologic retrograde sprouting of mossy fiber axons, both hallmarks of temporal lobe epilepsy. The characteristics of these sprouted synapses, however, have been largely unexplored, and the specific contribution of adult-born granule cells to functional mossy fiber sprouting is unknown, primarily due to technical barriers in isolating sprouted mossy fiber synapses for analysis. Here, we used DcxCreERT2 transgenic mice to permanently pulse-label age-defined cohorts of granule cells born either before or after pilocarpine-induced status epilepticus (SE). Using optogenetics, we demonstrate that adult-born granule cells born before SE form functional recurrent monosynaptic excitatory connections with other granule cells. Surprisingly, however, although healthy mossy fiber synapses in CA3 are well characterized "detonator" synapses that potently drive postsynaptic cell firing through their profound frequency-dependent facilitation, sprouted mossy fiber synapses from adult-born cells exhibited profound frequency-dependent depression, despite possessing some of the morphological hallmarks of mossy fiber terminals. Mature granule cells also contributed to functional mossy fiber sprouting, but exhibited less synaptic depression. Interestingly, granule cells born shortly after SE did not form functional excitatory synapses, despite robust sprouting. Our results suggest that, although sprouted mossy fibers form recurrent excitatory circuits with some of the morphological characteristics of typical mossy fiber terminals, the functional characteristics of sprouted synapses would limit the contribution of adult-born granule cells to hippocampal hyperexcitability in the epileptic hippocampus.SIGNIFICANCE STATEMENT In the hippocampal dentate gyrus, seizures drive retrograde sprouting of granule cell mossy fiber axons. We directly activated sprouted mossy fiber synapses from adult-born granule cells to study their synaptic properties. We reveal that sprouted synapses from adult-born granule cells have a diminished ability to sustain recurrent excitation in the epileptic hippocampus, which raises questions about the role of sprouting and adult neurogenesis in sustaining seizure-like activity.
Literature context: # AB2253, RRID:AB_1586992 Mouse mono
In many vertebrates, postnatally generated neurons often migrate long distances to reach their final destination, where they help shape local circuit activity. Concerted action of extrinsic stimuli is required to regulate long-distance migration. Some migratory principles are evolutionarily conserved, whereas others are species and cell type specific. Here we identified a serotonergic mechanism that governs migration of postnatally generated neurons in the mouse brain. Serotonergic axons originating from the raphe nuclei exhibit a conspicuous alignment with subventricular zone-derived neuroblasts. Optogenetic axonal activation provides functional evidence for serotonergic modulation of neuroblast migration. Furthermore, we show that the underlying mechanism involves serotonin receptor 3A (5HT3A)-mediated calcium influx. Thus, 5HT3A receptor deletion in neuroblasts impaired speed and directionality of migration and abolished calcium spikes. We speculate that serotonergic modulation of postnatally generated neuroblast migration is evolutionarily conserved as indicated by the presence of serotonergic axons in migratory paths in other vertebrates.
Literature context: illipore, RRID:AB_1586992), rabbit a
Significant migration cues are required to guide and contain newly generated rodent subventricular zone (SVZ) neuroblasts as they transit along the lateral ventricles and then through the anterior forebrain to their ultimate site of differentiation in the olfactory bulbs (OBs). These cues enforce strict neuroblast spatial boundaries within the dense astroglial meshwork of the SVZ and rostral migratory stream (RMS), yet are permissive to large-scale neuroblast migration. Therefore, the molecular mechanisms that define these cues and control dynamic interactions between migratory neuroblasts and surrounding astrocytes are of particular interest. We found that deletion of EphA4 and specifically ablation of EphA4 kinase activity resulted in misaligned neuroblasts and disorganized astrocytes in the RMS/SVZ, linking EphA4 forward signaling to SVZ and RMS spatial organization, orientation, and regulation. In addition, within a 3 week period, there was a significant reduction in the number of neuroblasts that reached the OB and integrated into the periglomerular layer, revealing a crucial role for EphA4 in facilitating efficient neuroblast migration to the OB. Single-cell analysis revealed that EPHA4 and its EFN binding partners are expressed by subpopulations of neuroblasts and astrocytes within the SVZ/RMS/OB system resulting in a cell-specific mosaic, suggesting complex EphA4 signaling involving both homotypic and heterotypic cell-cell interactions. Together, our studies reveal a novel molecular mechanism involving EphA4 signaling that functions in stem cell niche organization and ultimately neuroblast migration in the anterior forebrain.SIGNIFICANCE STATEMENT The subventricular zone neurogenic stem cell niche generates highly migratory neuroblasts that transit the anterior forebrain along a defined pathway to the olfactory bulb. Postnatal and adult brain organization dictates strict adherence to a narrow migration corridor. Subventricular zone neuroblasts are aligned in tightly bundled chains within a meshwork of astrocytes; however, the cell-cell cues that organize this unique, cell-dense migration pathway are largely unknown. Our studies show that forward signaling through the EphA4 tyrosine kinase receptor, mediated by ephrins expressed by subpopulations of neuroblasts and astrocytes, is required for compact, directional organization of neuroblasts and astrocytes within the pathway and efficient transit of neuroblasts through the anterior forebrain to the olfactory bulb.
Literature context: : AB2253; RRID:AB_1586992 Î³-Tubulin
The developmental mechanisms regulating the number of adult neural stem cells (aNSCs) are largely unknown. Here we show that the cleavage plane orientation in murine embryonic radial glia cells (RGCs) regulates the number of aNSCs in the lateral ganglionic eminence (LGE). Randomizing spindle orientation in RGCs by overexpression of Insc or a dominant-negative form of Lgn (dnLgn) reduces the frequency of self-renewing asymmetric divisions while favoring symmetric divisions generating two SNPs. Importantly, these changes during embryonic development result in reduced seeding of aNSCs. Interestingly, no effects on aNSC numbers were observed when Insc was overexpressed in postnatal RGCs or aNSCs. These data suggest a new mechanism for controlling aNSC numbers and show that the role of spindle orientation during brain development is highly time and region dependent.
Literature context: t# AB2253 RRID:AB1586992), or mouse
Sleep deprivation (SD) affects spatial memory and proliferation in the dentate gyrus. It is unknown whether these deleterious effects persist in the long run. The aim of this study was to evaluate the proliferation, differentiation and maturation of neural progenitors as well as spatial memory 21 days after suffering SD. Sixty-day old male Balb/C mice were exposed to 72-h REM-SD. Spatial memory, cell fate, apoptosis and expression levels of insulin-like growth factor 1 receptor (IGF-1R) were evaluated in the hippocampus at 0, 14, and 21 days after SD or control conditions. After 21-days recovery period, memory performance was assessed with the Barnes maze, we found a significant memory impairment in SD mice vs. control (94.0 ± 10.2 s vs. 25.2 ± 4.5 s; p < 0.001). The number of BrdU+ cells was significantly decreased in the SD groups at day 14 (controls = 1.6 ± 0.1 vs. SD mice = 1.2 ± 0.1 cells/field; p = 0.001) and at day 21 (controls = 0.2 ± 0.03 vs. SD mice = 0.1 ± 0.02 cells/field; p < 0.001). A statistically significant decrease was observed in neuronal differentiation (1.4 ± 0.1 cells/field vs. 0.9 ± 0.1 cells/field, p = 0.003). Apoptosis was significantly increased at day 14 after SD (0.53 ± 0.06 TUNEL+ cells/field) compared to controls (0.19 ± 0.03 TUNEL+ cells/field p < 0.001) and at 21-days after SD (SD mice 0.53 ± 0.15 TUNEL+ cells/field; p = 0.035). At day 0, IGF-1R expression showed a statistically significant reduction in SD animals (64.6 ± 12.2 units) when compared to the control group (102.0 ± 9.8 units; p = 0.043). However, no statistically significant differences were found at days 14 and 21 after SD. In conclusion, a single exposition to SD for 72-h can induce deleterious effects that persist for at least 3 weeks. These changes are characterized by spatial memory impairment, reduction in the number of hippocampal BrdU+ cells and persistent apoptosis rate. In contrast, changes IGF-1R expression appears to be a transient event. Highlight Sleep deprivation affects spatial memory and proliferation in the dentate gyrus. To date it is unknown whether these deleterious effects are persistent over a long period of time. We analyzed the effects of sleep deprivation in the hippocampus after 21 days of recovery sleep. Our findings indicate that after sleep recovery, the detrimental effects of SD can be observed for at least 2 weeks, as shown by a reduction in memory performance, changes in the hippocampal cellular composition and higher apoptotic rate over a long period of time.
Literature context: on;spines;AB_1586992;RRID:AB_10
In adult rodent olfactory bulb, GABAergic signaling regulates migration, differentiation, and synaptic integration of newborn granule cells (GCs), migrating from the subventricular zone. Here we show that these effects depend on the formation of a postsynaptic scaffold organized by gephyrin-the main scaffolding protein of GABAergic synapses, which anchors receptors and signaling molecules to the postsynaptic density-and are regulated by the phosphorylation status of gephyrin. Using lentiviral vectors to selectively transfect adult-born GCs, we observed that overexpression of the phospho-deficient gephyrin mutant eGFP-gephyrin(S270A), which facilitates the formation of supernumerary GABAergic synapses in vitro, favors dendritic branching and the formation of transient GABAergic synapses on spines, identified by the presence of α2-GABAA Rs. In contrast, overexpression of the dominant-negative eGFP-gephyrin(L2B) (a chimera that is enzymatically active but clustering defective), curtailed dendritic growth, spine formation, and long-term survival of GCs, pointing to the essential role of gephyrin cluster formation for its function. We could exclude any gephyrin overexpression artifacts, as GCs infected with eGFP-gephyrin were comparable to those infected with eGFP alone. The opposite effects induced by the two gephyrin mutant constructs indicate that the gephyrin scaffold at GABAergic synapses orchestrates signaling cascades acting on the cytoskeleton to regulate neuronal growth and synapse formation. Specifically, gephyrin phosphorylation emerges as a novel mechanism regulating morphological differentiation and long-term survival of adult-born olfactory bulb neurons.
Literature context: (C-terminus)Millipore, AB2253, AB_1586992, guinea pig, polyclonal1:2,000A
Two waves of oligodendrogenesis in the ventricular zone of the spinal cord (SC-VZ) during rat development, which take place between embryonic days 14 and 18 (E14-E18) and E20-E21, have been described. In the VZ of the brain, unlike the SC-VZ, a third wave of oligodendrogenesis occurs during the first weeks of postnatal development. Using immunofluorescence staining of intact rat SC tissue, we noticed the presence of small numbers of Olig2(+) /Sox-10(+) cells inside the lining of the central canal (CC) during postnatal development and adulthood. Olig2(+) /Sox-10(+) cells appeared inside the lining of the CC shortly after birth, and their number reached a maximum of approximately 0.65 ± 0.14 cell/40-μm section during the second postnatal week. After the latter development, the number of Olig2(+) /Sox-10(+) cells decreased to 0.21 ± 0.07 (P36) and 0.18 ± 0.1 cell/section (P120). At P21, Olig2(+) /Sox-10(+) cells inside the CC lining started to express other oligodendroglial markers such as CNPase, RIP, and APC. Olig2(+) /Sox-10(+) cells usually did not proliferate inside the CC lining and were only rarely found to be immunoreactive against oligodendrocyte progenitor markers such as NG2 or PDGFRα. Using 5-bromo-2-deoxyuridine administration at P2, P11, P22, or P120-P125, we revealed that these cells arose in the CC lining during postnatal development and adulthood. Our findings confirmed that the CC lining is the source of a small number of cells with an oligodendroglial phenotype during postnatal development and adulthood in the SC of intact rats.
Literature context: (Dcx) (1:500; Millipore, RRID:AB_2253), guinea pig anti-Ptf1a (1:400;
Horizontal cells are interneurons that synapse with photoreceptors in the outer retina. Their genesis during development is subject to regulation by transcription factors in a hierarchical manner. Previously, we showed that Onecut 1 (Oc1), an atypical homeodomain transcription factor, is expressed in developing horizontal cells (HCs) and retinal ganglion cells (RGCs) in the mouse retina. Herein, by knocking out Oc1 specifically in the developing retina, we show that the majority (∼80%) of HCs fail to form during early retinal development, implying that Oc1 is essential for HC genesis. However, no other retinal cell types, including RGCs, were affected in the Oc1 knock-out. Analysis of the genetic relationship between Oc1 and other transcription factor genes required for HC development revealed that Oc1 functions downstream of FoxN4, in parallel with Ptf1a, but upstream of Lim1 and Prox1. By in utero electroporation, we found that Oc1 and Ptf1a together are not only essential, but also sufficient for determination of HC fate. In addition, the synaptic connections in the outer plexiform layer are defective in Oc1-null mice, and photoreceptors undergo age-dependent degeneration, indicating that HCs are not only an integral part of the retinal circuitry, but also are essential for the survival of photoreceptors. In sum, these results demonstrate that Oc1 is a critical determinant of HC fate, and reveal that HCs are essential for photoreceptor viability, retinal integrity, and normal visual function.
We have demonstrated that cortical cell autografts might be a useful therapy in two monkey models of neurological disease: motor cortex lesion and Parkinson's disease. However, the origin of the useful transplanted cells obtained from cortical biopsies is not clear. In this report we describe the expression of doublecortin (DCX) in these cells based on reverse-transcription polymerase chain reaction (RT-PCR) and immunodetection in the adult primate cortex and cell cultures. The results showed that DCX-positive cells were present in the whole primate cerebral cortex and also expressed glial and/or neuronal markers such as glial fibrillary protein (GFAP) or neuronal nuclei (NeuN). We also demonstrated that only DCX/GFAP positive cells were able to proliferate and originate progenitor cells in vitro. We hypothesize that these DCX-positive cells in vivo have a role in cortical plasticity and brain reaction to injury. Moreover, in vitro these DCX-positive cells have the potential to reacquire progenitor characteristics that confirm their potential for brain repair.