bcl-2 protein expression is widespread in the developing nervous system and retained in the adult PNS

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 301-311 ◽  
Author(s):  
D.E. Merry ◽  
D.J. Veis ◽  
W.F. Hickey ◽  
S.J. Korsmeyer

Cell death is a common feature of neural development in all vertebrates. The bcl-2 proto-oncogene has been shown to protect a variety of cell types from programmed cell death. We have examined the distribution of bcl-2 protein in the developing and adult nervous systems. bcl-2 protein is widespread during embryonic development. Proliferating neuroepithelial cells of ventricular zones as well as the postmitotic cells of the cortical plate, cerebellum, hippocampus and spinal cord express bcl-2. Postnatally, bcl-2 is principally retained in the granule cells of the cerebellum and dentate gyrus of the hippocampus. bcl-2 expression in the CNS declines with aging. In the peripheral nervous system, neurons and supporting cells of sympathetic and sensory ganglia retain substantial bcl-2 protein throughout life. The widespread expression of bcl-2 in CNS and PNS neurons during embryonic development and its selective retention in the adult PNS is consistent with a role for bcl-2 in regulating neuronal survival. In addition, the expression of bcl-2 in some neuronal populations beyond the recognized period of cell death is suggestive of a role for bcl-2 beyond simply protecting neurons from developmental cell death.

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 91
Author(s):  
Verena Schultz ◽  
Stephanie L. Cumberworth ◽  
Quan Gu ◽  
Natasha Johnson ◽  
Claire L. Donald ◽  
...  

Understanding how Zika virus (Flaviviridae; ZIKV) affects neural cells is paramount in comprehending pathologies associated with infection. Whilst the effects of ZIKV in neural development are well documented, impact on the adult nervous system remains obscure. Here, we investigated the effects of ZIKV infection in established mature myelinated central nervous system (CNS) cultures. Infection incurred damage to myelinated fibers, with ZIKV-positive cells appearing when myelin damage was first detected as well as axonal pathology, suggesting the latter was a consequence of oligodendroglia infection. Transcriptome analysis revealed host factors that were upregulated during ZIKV infection. One such factor, CCL5, was validated in vitro as inhibiting myelination. Transferred UV-inactivated media from infected cultures did not damage myelin and axons, suggesting that viral replication is necessary to induce the observed effects. These data show that ZIKV infection affects CNS cells even after myelination—which is critical for saltatory conduction and neuronal function—has taken place. Understanding the targets of this virus across developmental stages including the mature CNS, and the subsequent effects of infection of cell types, is necessary to understand effective time frames for therapeutic intervention.


Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1641-1649
Author(s):  
B. Diaz ◽  
J. Serna ◽  
F. De Pablo ◽  
E.J. de la Rosa

Programmed cell death is an established developmental process in the nervous system. Whereas the regulation and the developmental role of neuronal cell death have been widely demonstrated, the relevance of cell death during early neurogenesis, the cells affected and the identity of regulatory local growth factors remain poorly characterized. We have previously described specific in vivo patterns of apoptosis during early retinal neurogenesis, and that exogenous insulin acts as survival factor (Diaz, B., Pimentel, B., De Pablo, F. and de la Rosa, E. J. (1999) Eur. J. Neurosci. 11, 1624–1632). Proinsulin mRNA was found to be expressed broadly in the early embryonic chick retina, and decreased later between days 6 and 8 of embryonic development, when there was increased expression of insulin-like growth factor I mRNA, absent or very scarce at earlier stages. Consequently, we studied whether proinsulin and/or insulin ((pro)insulin) action in prevention of cell death has physiological relevance during early neural development. In ovo treatment at day 2 of embryonic development with specific antibodies against (pro)insulin or the insulin receptor induced apoptosis in the neuroretina. The distribution of apoptotic cells two days after the blockade was similar to naturally occurring cell death, as visualized by TdT-mediated dUTP nick end labeling. The apoptosis induced by the insulin receptor blockade preferentially affected to the Islet1/2 positive cells, that is, the differentiated retinal ganglion cells. In parallel, the insulin survival effect on cultured retinas correlated with the activation of Akt to a greater extent than with the activation of MAP kinase. These results suggest that the physiological cell death occurring in early stages of retinal development is regulated by locally produced (pro)insulin through the activation of the Akt survival pathway.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Stephen Johnston ◽  
Sarah Parylak ◽  
Stacy Kim ◽  
Nolan Mac ◽  
Christina Lim ◽  
...  

Recombinant adeno-associated virus (rAAV) has been widely used as a viral vector across mammalian biology and has been shown to be safe and effective in human gene therapy. We demonstrate that neural progenitor cells (NPCs) and immature dentate granule cells (DGCs) within the adult murine hippocampus are particularly sensitive to rAAV-induced cell death. Cell loss is dose dependent and nearly complete at experimentally relevant viral titers. rAAV-induced cell death is rapid and persistent, with loss of BrdU-labeled cells within 18 hours post-injection and no evidence of recovery of adult neurogenesis at 3 months post-injection. The remaining mature DGCs appear hyperactive 4 weeks post-injection based on immediate early gene expression, consistent with previous studies investigating the effects of attenuating adult neurogenesis. In vitro application of AAV or electroporation of AAV2 inverted terminal repeats (ITRs) is sufficient to induce cell death. Efficient transduction of the dentate gyrus (DG)-without ablating adult neurogenesis-can be achieved by injection of rAAV2-retro serotyped virus into CA3. rAAV2-retro results in efficient retrograde labeling of mature DGCs and permits in vivo 2-photon calcium imaging of dentate activity while leaving adult neurogenesis intact. These findings expand on recent reports implicating rAAV-linked toxicity in stem cells and other cell types and suggest that future work using rAAV as an experimental tool in the DG and as a gene therapy for diseases of the central nervous system (CNS) should be carefully evaluated.


2018 ◽  
Vol 6 (4) ◽  
pp. 26 ◽  
Author(s):  
Alla Yalonetskaya ◽  
Albert Mondragon ◽  
Johnny Elguero ◽  
Kimberly McCall

Cell proliferation and cell death are two opposing, yet complementary fundamental processes in development. Cell proliferation provides new cells, while developmental programmed cell death adjusts cell numbers and refines structures as an organism grows. Apoptosis is the best-characterized form of programmed cell death; however, there are many other non-apoptotic forms of cell death that occur throughout development. Drosophila is an excellent model for studying these varied forms of cell death given the array of cellular, molecular, and genetic techniques available. In this review, we discuss select examples of apoptotic and non-apoptotic cell death that occur in different tissues and at different stages of Drosophila development. For example, apoptosis occurs throughout the nervous system to achieve an appropriate number of neurons. Elsewhere in the fly, non-apoptotic modes of developmental cell death are employed, such as in the elimination of larval salivary glands and midgut during metamorphosis. These and other examples discussed here demonstrate the versatility of Drosophila as a model organism for elucidating the diverse modes of programmed cell death.


2018 ◽  
Vol 19 (12) ◽  
pp. 4131 ◽  
Author(s):  
Jessica Fletcher ◽  
Simon Murray ◽  
Junhua Xiao

Brain-derived neurotrophic factor (BDNF) plays vitally important roles in neural development and plasticity in both health and disease. Recent studies using mutant mice to selectively manipulate BDNF signalling in desired cell types, in combination with animal models of demyelinating disease, have demonstrated that BDNF not only potentiates normal central nervous system myelination in development but enhances recovery after myelin injury. However, the precise mechanisms by which BDNF enhances myelination in development and repair are unclear. Here, we review some of the recent progress made in understanding the influence BDNF exerts upon the myelinating process during development and after injury, and discuss the cellular and molecular mechanisms underlying its effects. In doing so, we raise new questions for future research.


Science ◽  
2019 ◽  
Vol 365 (6456) ◽  
pp. eaaw8231 ◽  
Author(s):  
Tracey A. C. S. Suter ◽  
Alexander Jaworski

The central and peripheral nervous system (CNS and PNS, respectively) are composed of distinct neuronal and glial cell types with specialized functional properties. However, a small number of select cells traverse the CNS-PNS boundary and connect these two major subdivisions of the nervous system. This pattern of segregation and selective connectivity is established during embryonic development, when neurons and glia migrate to their destinations and axons project to their targets. Here, we provide an overview of the cellular and molecular mechanisms that control cell migration and axon guidance at the vertebrate CNS-PNS border. We highlight recent advances on how cell bodies and axons are instructed to either cross or respect this boundary, and present open questions concerning the development and plasticity of the CNS-PNS interface.


Author(s):  
ST Johnston ◽  
SL Parylak ◽  
S Kim ◽  
N Mac ◽  
CK Lim ◽  
...  

ABSTRACTRecombinant adeno-associated virus (rAAV) has been widely used as a viral vector across mammalian biology and has been shown to be safe and effective in human gene therapy. We demonstrate that neural progenitor cells (NPCs) and immature dentate granule cells (DGCs) within the adult murine hippocampus are particularly sensitive to rAAV-induced cell death. Cell loss is dose dependent and nearly complete at experimentally relevant viral titers. rAAV-induced cell death is rapid and persistent, with loss of BrdU-labeled cells within 18 hours post-injection and no evidence of recovery of adult neurogenesis at 3 months post-injection. The remaining mature DGCs appear hyperactive 4 weeks post-injection based on immediate early gene expression, consistent with previous studies investigating the effects of attenuating adult neurogenesis. In vitro application of AAV or electroporation of AAV2 inverted terminal repeats (ITRs) is sufficient to induce cell death. Efficient transduction of the dentate gyrus (DG)—without ablating adult neurogenesis—can be achieved by injection of rAAV2-retro serotyped virus into CA3. rAAV2-retro results in efficient retrograde labeling of mature DGCs and permits in vivo 2-photon calcium imaging of dentate activity while leaving adult neurogenesis intact. These findings expand on recent reports implicating rAAV-linked toxicity in stem cells and other cell types and suggest that future work using rAAV as an experimental tool in the DG and as a gene therapy for diseases of the central nervous system (CNS) should be carefully evaluated.


2011 ◽  
Vol 59 (11) ◽  
pp. 976-983 ◽  
Author(s):  
Arindam P. Ghosh ◽  
Jennifer D. Cape ◽  
Barbara J. Klocke ◽  
Kevin A. Roth

The BCL-2 family includes both pro- and anti-apoptotic proteins, which regulate programmed cell death during development and in response to various apoptotic stimuli. The BH3-only subgroup of pro-apoptotic BCL-2 family members is critical for the induction of apoptotic signaling, by binding to and neutralizing anti-apoptotic BCL-2 family members. During embryonic development, the anti-apoptotic protein BCL-XL plays a critical role in the survival of neuronal populations by regulating the multi-BH domain protein BAX. In this study, the authors investigated the role of Harakiri (HRK), a relatively recently characterized BH3-only molecule in disrupting the BAX-BCL-XL interaction during nervous system development. Results indicate that HRK deficiency significantly reduces programmed cell death in the nervous system. However, HRK deficiency does not significantly attenuate the widespread apoptosis seen in the Bcl-x−/− embryonic nervous system, indicating that other BH3-only molecules, alone or in combination, may regulate BAX activation in immature neurons.


1987 ◽  
Vol 105 (6) ◽  
pp. 3065-3073 ◽  
Author(s):  
F D Miller ◽  
C C Naus ◽  
M Durand ◽  
F E Bloom ◽  
R J Milner

The mRNAs for two isotypes of alpha-tubulin, termed T alpha 1 and T26, are known to be expressed in the rat nervous system. We have compared the expression of these two alpha-tubulin mRNAs during neural development, using RNA blotting and in situ hybridization techniques with probes directed against unique sequences of each mRNA. T alpha 1 mRNA is highly enriched in the embryonic nervous system but is markedly less abundant in the adult brain; T26 mRNA is expressed in many embryonic tissues with little change in abundance during development. Within the nervous system, T alpha 1 mRNA is enriched in regions with neurons actively undergoing neurite extension, such as the cortical plate, whereas T26 mRNA is relatively homogeneous in distribution, with some enrichment in proliferative zones. Expression of T alpha 1 mRNA is also increased in PC12 cells induced to differentiate and extend neurite processes by nerve growth factor. Taken together, the data indicate that T alpha 1-tubulin mRNA is expressed at high levels during the extension of neuronal processes. The abundant expression of T alpha 1-tubulin mRNA may therefore reflect either a means to increase the available pool of alpha-tubulin or a specific requirement for the T alpha 1 isotype for neurite extension.


2020 ◽  
Author(s):  
J. Schnabl ◽  
M.P.H. Litz ◽  
C. Schneider ◽  
N. PenkoffLidbeck ◽  
S. Bashiruddin ◽  
...  

AbstractDuring embryonic development of bilateral organisms, neurons send axons across the midline at specific points to connect the two halves of the nervous system with a commissure. Little is known about the cells at the midline that facilitate this tightly regulated process. We exploit the con served process of vertebrate embryonic development in the zebrafish model system to elucidate the identity of cells at the midline that may facilitate postoptic (POC) and anterior commissure (AC) development. We have discovered that three differentgfap+ astroglial cell morphologies persist in contact with pathfinding axons throughout commissure formation. Similarly, olig2+ progenitor cells occupy delineated portions of the postoptic and anterior commissures. These early olig2+ progenitors demonstrate glial-like morphologies despite the lack of a myelination marker. Moreover, we conclude that both the gfap+ and olig2+progenitor cells give rise to neuronal populations in both the telencephalon and diencephalon. Interestingly, these varied cell populations showed significant developmental heterochrony between the telencephalon and diencephalon. Lastly, we also showed that fli1a+ mesenchymal cells migrate along the presumptive commissure regions before and during midline axon crossing. Furthermore, following commissure maturation, specific blood vessels formed at the midline of the POC and immediately ventral and parallel to the AC. This comprehensive account of the cellular populations that correlate with the timing and position of commissural axon pathfinding has supported the conceptual modeling and identification of the early forebrain architecture that may be necessary for proper commissure development.


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