scholarly journals Glial PAMPering and DAMPening of Adult Hippocampal Neurogenesis

2021 ◽  
Vol 11 (10) ◽  
pp. 1299
Author(s):  
Luke Parkitny ◽  
Mirjana Maletic-Savatic
Keyword(s):  
Cell Fate ◽  
Glial Cells ◽  
Cognitive Disorders ◽  
Hippocampal Neurogenesis ◽  
Innate Immune ◽  
Adult Hippocampal Neurogenesis ◽  
Sterile Inflammation ◽  
System Response ◽  
Danger Signals ◽  
Neurogenic Niche

Adult neurogenesis represents a mature brain’s capacity to integrate newly generated neurons into functional circuits. Impairment of neurogenesis contributes to the pathophysiology of various mood and cognitive disorders such as depression and Alzheimer’s Disease. The hippocampal neurogenic niche hosts neural progenitors, glia, and vasculature, which all respond to intrinsic and environmental cues, helping determine their current state and ultimate fate. In this article we focus on the major immune communication pathways and mechanisms through which glial cells sense, interact with, and modulate the neurogenic niche. We pay particular attention to those related to the sensing of and response to innate immune danger signals. Receptors for danger signals were first discovered as a critical component of the innate immune system response to pathogens but are now also recognized to play a crucial role in modulating non-pathogenic sterile inflammation. In the neurogenic niche, viable, stressed, apoptotic, and dying cells can activate danger responses in neuroimmune cells, resulting in neuroprotection or neurotoxicity. Through these mechanisms glial cells can influence hippocampal stem cell fate, survival, neuronal maturation, and integration. Depending on the context, such responses may be appropriate and on-target, as in the case of learning-associated synaptic pruning, or excessive and off-target, as in neurodegenerative disorders.

Neuroinflammation and physical exercise as modulators of adult hippocampal neural precursor cell behavior

2017 ◽  
Vol 29 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Martha Pérez-Domínguez ◽  
Luis B. Tovar-y-Romo ◽  
Angélica Zepeda
Keyword(s):  
Stem Cells ◽  
Physical Exercise ◽  
Neural Stem Cells ◽  
Cell Fate ◽  
Bone Morphogenetic Proteins ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Adult Neural Stem Cells ◽  
Neurogenic Niche ◽  
Glial Lineage

Abstract The dentate gyrus of the hippocampus is a plastic structure where adult neurogenesis constitutively occurs. Cell components of the neurogenic niche are source of paracrine as well as membrane-bound factors such as Notch, Bone Morphogenetic Proteins, Wnts, Sonic Hedgehog, cytokines, and growth factors that regulate adult hippocampal neurogenesis and cell fate decision. The integration and coordinated action of multiple extrinsic and intrinsic cues drive a continuous decision process: if adult neural stem cells remain quiescent or proliferate, if they take a neuronal or a glial lineage, and if new cells proliferate, undergo apoptotic death, or survive. The proper balance in the molecular milieu of this neurogenic niche leads to the production of neurons in a higher rate as that of astrocytes. But this rate changes in face of microenvironment modifications as those driven by physical exercise or with neuroinflammation. In this work, we first review the cellular and molecular components of the subgranular zone, focusing on the molecules, active signaling pathways and genetic programs that maintain quiescence, induce proliferation, or promote differentiation. We then summarize the evidence regarding the role of neuroinflammation and physical exercise in the modulation of adult hippocampal neurogenesis with emphasis on the activation of progression from adult neural stem cells to lineage-committed progenitors to their progeny mainly in murine models.

Metabolic Regulation of Hippocampal Neuronal Development and Its Inhibition After Irradiation

2021 ◽  
Vol 80 (5) ◽  
pp. 467-475
Author(s):  
Yu-Qing Li ◽  
C Shun Wong
Keyword(s):  
Cell Fate ◽  
Metabolic Regulation ◽  
Energy Homeostasis ◽  
Neuronal Development ◽  
Adenosine Monophosphate ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Wild Type ◽  
Newborn Neuron ◽  
Negative Effect

Abstract 5′-Adenosine monophosphate-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, plays a role in cell fate determination. Whether AMPK regulates hippocampal neuronal development remains unclear. Hippocampal neurogenesis is abrogated after DNA damage. Here, we asked whether AMPK regulates adult hippocampal neurogenesis and its inhibition following irradiation. Adult Cre-lox mice deficient in AMPK in brain, and wild-type mice were used in a birth-dating study using bromodeoxyuridine to evaluate hippocampal neurogenesis. There was no evidence of AMPK or phospho-AMPK immunoreactivity in hippocampus. Increase in p-AMPK but not AMPK expression was observed in granule neurons and subgranular neuroprogenitor cells (NPCs) in the dentate gyrus within 24 hours and persisted up to 9 weeks after irradiation. AMPK deficiency in Cre-lox mice did not alter neuroblast and newborn neuron numbers but resulted in decreased newborn and proliferating NPCs. Inhibition of neurogenesis was observed after irradiation regardless of genotypes. In Cre-lox mice, there was further loss of newborn early NPCs and neuroblasts but not newborn neurons after irradiation compared with wild-type mice. These results are consistent with differential negative effect of AMPK on hippocampal neuronal development and its inhibition after irradiation.

scholarly journals JNK1 controls adult hippocampal neurogenesis and imposes cell-autonomous control of anxiety behaviour from the neurogenic niche

2016 ◽  
Vol 23 (2) ◽  
pp. 362-374 ◽  
Author(s):  
H Mohammad ◽  
F Marchisella ◽  
S Ortega-Martinez ◽  
P Hollos ◽  
K Eerola ◽  
...  
Keyword(s):  
Hippocampal Neurogenesis ◽  
Autonomous Control ◽  
Adult Hippocampal Neurogenesis ◽  
Neurogenic Niche

scholarly journals De novo DNA methylation controls neuronal maturation during adult hippocampal neurogenesis

2020 ◽  
Author(s):  
Sara Zocher ◽  
Rupert W Overall ◽  
Gabriel Berdugo-Vega ◽  
Nicole Rund ◽  
Anne Karasinsky ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Fate ◽  
Adult Neurogenesis ◽  
Hippocampal Neurons ◽  
De Novo ◽  
Functional Integration ◽  
Stem Cell Differentiation ◽  
Dna Methyltransferases ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis

SummaryDynamic DNA methylation controls gene-regulatory networks underlying cell fate specification. How DNA methylation patterns change during adult hippocampal neurogenesis and their relevance for adult neural stem cell differentiation and related brain function has, however, remained unknown. Here, we show that neurogenesis-associated de novo DNA methylation is critical for maturation and functional integration of adult-born hippocampal neurons. Cell stage-specific bisulfite sequencing revealed a pronounced gain of DNA methylation at neuronal enhancers, gene bodies and binding sites of pro-neuronal transcription factors during adult neurogenesis, which mostly correlated with transcriptional up-regulation of the associated loci. Inducible deletion of both de novo DNA methyltransferases Dnmt3a and Dnmt3b in adult neural stem cells specifically impaired dendritic outgrowth and synaptogenesis of new-born neurons, resulting in reduced hippocampal excitability and specific deficits in hippocampus-dependent learning and memory. Our results highlight that, during adult neurogenesis, remodeling of neuronal methylomes is fundamental for proper hippocampal function.

scholarly journals Unique Microglial Transcriptomic Signature within the Hippocampal Neurogenic Niche

2021 ◽  
Author(s):  
Sana Chintamen ◽  
Pallavi Gaur ◽  
Nicole Vo ◽  
Elizabeth Bradshaw ◽  
Vilas Menon ◽  
...  
Keyword(s):  
Gene Signature ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Neurogenic Niche ◽  
Expression Of Genes ◽  
Transcriptomic Signature ◽  
Specialized Population ◽  
Lower Expression

Microglia, the resident immune cells of the brain, are crucial in the development of the nervous system. Recent evidence demonstrates that microglia modulate adult hippocampal neurogenesis by inhibiting cell proliferation of neural precursors and survival both in vitro and in vivo, thus maintaining a balance between cell division and cell death in the neural stem cell pool. There are increasing reports suggesting these microglia found in neurogenic niches differ from their counterparts in non-neurogenic areas. Here, we present evidence that microglia in the hippocampal neurogenic niche are a specialized population that express genes known to regulate neurogenesis. By comprehensively profiling myeloid lineage cells in the hippocampus using single cell RNA-sequencing, we resolve transcriptomic differences in microglia originating from the subgranular zone. These cells have lower expression of genes associated with homeostatic microglia and increased expression of genes associated with phagocytosis. Intriguingly, this small yet distinct population expresses a gene signature with substantial overlap with previously characterized phenotypes, including disease associated microglia (DAM), a particularly unique and compelling microglial state.

scholarly journals Norbin ablation results in defective adult hippocampal neurogenesis and depressive-like behavior in mice

2015 ◽  
Vol 112 (31) ◽  
pp. 9745-9750 ◽  
Author(s):  
Hong Wang ◽  
Jennifer Warner-Schmidt ◽  
Santiago Varela ◽  
Grigori Enikolopov ◽  
Paul Greengard ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Cell Fate ◽  
Adult Neurogenesis ◽  
Metabotropic Glutamate Receptors ◽  
Forced Swim Test ◽  
Critical Role ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Cell Contact

Adult neurogenesis in the hippocampus subgranular zone is associated with the etiology and treatment efficiency of depression. Factors that affect adult hippocampal neurogenesis have been shown to contribute to the neuropathology of depression. Glutamate, the major excitatory neurotransmitter, plays a critical role in different aspects of neurogenesis. Of the eight metabotropic glutamate receptors (mGluRs), mGluR5 is the most highly expressed in neural stem cells. We previously identified Norbin as a positive regulator of mGluR5 and showed that its expression promotes neurite outgrowth. In this study, we investigated the role of Norbin in adult neurogenesis and depressive-like behaviors using Norbin-deficient mice. We found that Norbin deletion significantly reduced hippocampal neurogenesis; specifically, the loss of Norbin impaired the proliferation and maturation of newborn neurons without affecting cell-fate specification of neural stem cells/neural progenitor cells (NSCs/NPCs). Norbin is highly expressed in the granular neurons in the dentate gyrus of the hippocampus, but it is undetectable in NSCs/NPCs or immature neurons, suggesting that the effect of Norbin on neurogenesis is likely caused by a nonautonomous niche effect. In support of this hypothesis, we found that the expression of a cell–cell contact gene, Desmoplakin, is greatly reduced in Norbin-deletion mice. Moreover, Norbin-KO mice show an increased immobility in the forced-swim test and the tail-suspension test and reduced sucrose preference compared with wild-type controls. Taken together, these results show that Norbin is a regulator of adult hippocampal neurogenesis and that its deletion causes depressive-like behaviors.

scholarly journals Targeted Dorsal Dentate Gyrus or Whole Brain Irradiation in Juvenile Mice Differently Affects Spatial Memory and Adult Hippocampal Neurogenesis

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 192
Author(s):  
Céline Serrano ◽  
Morgane Dos Santos ◽  
Dimitri Kereselidze ◽  
Louison Beugnies ◽  
Philippe Lestaevel ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Dentate Gyrus ◽  
Memory Retrieval ◽  
Cognitive Disorders ◽  
Volume Effect ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Dose Effect ◽  
Whole Brain Irradiation ◽  
Whole Brain

The cognitive consequences of postnatal brain exposure to ionizing radiation (IR) at low to moderate doses in the adult are not fully established. Because of the advent of pediatric computed tomography scans used for head exploration, improving our knowledge of these effects represents a major scientific challenge. To evaluate how IR may affect the developing brain, models of either whole brain (WB) or targeted dorsal dentate gyrus (DDG) irradiation in C57Bl/6J ten-day-old male mice were previously developed. Here, using these models, we assessed and compared the effect of IR (doses range: 0.25–2 Gy) on long-term spatial memory in adulthood using a spatial water maze task. We then evaluated the effects of IR exposure on adult hippocampal neurogenesis, a form of plasticity involved in spatial memory. Three months after WB exposure, none of the doses resulted in spatial memory impairment. In contrast, a deficit in memory retrieval was identified after DDG exposure for the dose of 1 Gy only, highlighting a non-monotonic dose-effect relationship in this model. At this dose, a brain irradiated volume effect was also observed when studying adult hippocampal neurogenesis in the two models. In particular, only DDG exposure caused alteration in cell differentiation. The most deleterious effect observed in adult hippocampal neurogenesis after targeted DDG exposure at 1 Gy may contribute to the memory retrieval deficit in this model. Altogether these results highlight the complexity of IR mechanisms in the brain that can lead or not to cognitive disorders and provide new knowledge of interest for the radiation protection of children.

scholarly journals Molecular markers characterization determining cell fate specification in an adult neurogenesis model of Alzheimer’s disease

2020 ◽  
Author(s):  
Idoia Blanco-Luquin ◽  
Juan Cabello ◽  
Amaya Urdánoz-Casado ◽  
Blanca Acha ◽  
Eva Ma Gómez-Orte ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mrna Expression ◽  
Cell Fate ◽  
Adult Neurogenesis ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Altered Expression ◽  
Model Of Alzheimer’S Disease

ABSTRACTAdult hippocampal neurogenesis (AHN) study is still a challenge. In addition to methodological difficulties is the controversy of results derived of human or animal system approaches. In view of the proven link between AHN and learning and memory impairment, we generated a straightforward in vitro model to recapitulate adult neurogenesis in the context of Alzheimer’s disease (AD).Neural progenitor cells (NPCs) monolayer culture was differentiated for a period of 29 days and Aβ peptide 1-42 was administered once a week. mRNA expression of NEUROD1, NCAM1, TUBB3, RBFOX3, CALB1 and GFAP genes was determined by RT-qPCR.Phenotypic changes were observed during directed differentiation. Except for GFAP and CALB1, these changes correlated with altered expression profile of all genes since 9 days. Only TUBB3 expression remained constant while NEUROD1, NCAM1 and RBFOX3 expression increased over time. Moreover, Aβ treated NPCs showed transient decreases of mRNA expression for NCAM1, TUBB3 and RBFOX3 genes at 9 or 19 days.Our in vitro human NPCs model is framed within the multistep process of AHN in the SGZ of the DG. Remarkably, its transcriptional assessment might reflect alterations detected in AD human patients, deepening our understanding of the disorder and possibly of its pathogenesis.SUMMARY STATEMENTTranscriptional profile of a number of genes recapitulating particular stages of Adult hippocampal neurogenesis in the context of Alzheimer’s disease

scholarly journals Chronic stress induces significant gene expression changes in the prefrontal cortex alongside alterations in adult hippocampal neurogenesis

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Ksenia Musaelyan ◽  
Selin Yildizoglu ◽  
James Bozeman ◽  
Andrea Du Preez ◽  
Martin Egeland ◽  
...  
Keyword(s):  
Gene Expression ◽  
Prefrontal Cortex ◽  
Chronic Stress ◽  
Molecular Mechanisms ◽  
Dendritic Tree ◽  
Hippocampal Neurogenesis ◽  
Stress Disorders ◽  
Adult Hippocampal Neurogenesis ◽  
Mild Stress ◽  
Neurogenic Niche

Abstract Adult hippocampal neurogenesis is involved in stress-related disorders such as depression, posttraumatic stress disorders, as well as in the mechanism of antidepressant effects. However, the molecular mechanisms involved in these associations remain to be fully explored. In this study, unpredictable chronic mild stress in mice resulted in a deficit in neuronal dendritic tree development and neuroblast migration in the hippocampal neurogenic niche. To investigate molecular pathways underlying neurogenesis alteration, genome-wide gene expression changes were assessed in the prefrontal cortex, hippocampus and the hypothalamus alongside neurogenesis changes. Cluster analysis showed that the transcriptomic signature of chronic stress is much more prominent in the prefrontal cortex compared to the hippocampus and the hypothalamus. Pathway analyses suggested huntingtin, leptin, myelin regulatory factor, methyl-CpG binding protein and brain-derived neurotrophic factor as the top predicted upstream regulators of transcriptomic changes in the prefrontal cortex. Involvement of the satiety regulating pathways (leptin) was corroborated by behavioural data showing increased food reward motivation in stressed mice. Behavioural and gene expression data also suggested circadian rhythm disruption and activation of circadian clock genes such as Period 2. Interestingly, most of these pathways have been previously shown to be involved in the regulation of adult hippocampal neurogenesis. It is possible that activation of these pathways in the prefrontal cortex by chronic stress indirectly affects neuronal differentiation and migration in the hippocampal neurogenic niche via reciprocal connections between the two brain areas.

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