Search results for " Neurogenesis"

Chromatin remodelling factor Mll1 is essential for neurogenesis from postnatal neural stem cells

2009

Epigenetic mechanisms that maintain neurogenesis throughout adult life remain poorly understood(1). Trithorax group (trxG) and Polycomb group (PcG) gene products are part of an evolutionarily conserved chromatin remodelling system that activate or silence gene expression, respectively(2). Although PcG member Bmi1 has been shown to be required for postnatal neural stem cell self-renewal(3,4), the role of trxG genes remains unknown. Here we show that the trxG member Mll1 (mixed-lineage leukaemia 1) is required for neurogenesis in the mouse postnatal brain. Mll1-deficient subventricular zone neural stem cells survive, proliferate and efficiently differentiate into glial lineages; however, neur…

Dynamic Changes in the Neurogenic Potential in the Ventricular–Subventricular Zone of Common Marmoset during Postnatal Brain Development

2020

AbstractEven after birth, neuronal production continues in the ventricular–subventricular zone (V–SVZ) and hippocampus in many mammals. The immature new neurons (“neuroblasts”) migrate and then mature at their final destination. In humans, neuroblast production and migration toward the neocortex and the olfactory bulb (OB) occur actively only for a few months after birth and then sharply decline with age. However, the precise spatiotemporal profiles and fates of postnatally born neurons remain unclear due to methodological limitations. We previously found that common marmosets, small nonhuman primates, share many features of V–SVZ organization with humans. Here, using marmosets injected wit…

Functional Integration of Neuronal Precursors in the Adult Murine Piriform Cortex

2018

Abstract The extent of functional maturation and integration of nonproliferative neuronal precursors, becoming neurons in the adult murine piriform cortex, is largely unexplored. We thus questioned whether precursors eventually become equivalent to neighboring principal neurons or whether they represent a novel functional network element. Adult brain neuronal precursors and immature neurons (complex cells) were labeled in transgenic mice (DCX-DsRed and DCX-CreERT2 /flox-EGFP), and their cell fate was characterized with patch clamp experiments and morphometric analysis of axon initial segments. Young (DCX+) complex cells in the piriform cortex of 2- to 4-month-old mice received sparse synapt…

Axons take a dive

2014

In the walls of the lateral ventricles of the adult mammalian brain, neural stem cells (NSCs) and ependymal (E1) cells share the apical surface of the ventricular-subventricular zone (V-SVZ). In a recent article, we show that supraependymal serotonergic (5HT) axons originating from the raphe nuclei in mice form an extensive plexus on the walls of the lateral ventricles where they contact E1 cells and NSCs. Here we further characterize the contacts between 5HT supraependymal axons and E1 cells in mice, and show that suprependymal axons tightly associated to E1 cells are also present in the walls of the human lateral ventricles. These observations raise interesting questions about the functio…

FGF-2/FGFR neurotrophic system expression level does not give account for the age-related decline of neurogenesis in the rat brain.

2009

Redox regulation of genome stability by effects on gene expression, epigenetic pathways and DNA damage/repair

2015

Reactive oxygen and nitrogen species (e.g. H2O2, nitric oxide) confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. In addition, classical regulation of gene expression or activity, including gene transcription to RNA followed by translation to the protein level, by transcription factors (e.g. NF-κB, HIF-1α) and mRNA binding proteins (e.g. GAPDH, HuR) is subject to redox regulation. This review will give an update of recent discoveries in this field, and specifically highlight the impact of reactive oxygen and nitrogen species on DNA repair systems that contribute to genomic stability. Emphasis will be placed …

Glutathione and cellular redox control in epigenetic regulation.

2015

Epigenetics is defined as the mitotically/meiotically heritable changes in gene expression that are not due to changes in the primary DNA sequence. Over recent years, growing evidence has suggested a link between redox metabolism and the control of epigenetic mechanisms. The effect of the redox control, oxidative stress, and glutathione (GSH) on the epigenetic mechanisms occur at different levels affecting DNA methylation, miRNAs expression, and histone post-translational modifications (PTMs). Furthermore, a number of redox PTMs are being described, so enriching the histone code. Pioneer works showed how oxidized GSH inhibits the activity of S-adenosyl methionine synthetase, MAT1A, a key en…

PSA-NCAM is expressed in immature, but not recently generated, neurons in the adult cat cerebral cortex layer II

2011

Neuronal production persists during adulthood in the dentate gyrus and the olfactory bulb, where substantial numbers of immature neurons can be found. These cells can also be found in the paleocortex layer II of adult rodents, but in this case most of them have been generated during embryogenesis. Recent reports have described the presence of similar cells, with a wider distribution, in the cerebral cortex of adult cats and primates and have suggested that they may develop into interneurons. The objective of this study is to verify this hypothesis and to explore the origin of these immature neurons in adult cats. We have analyzed their distribution using immunohistochemical analysis of the …

Neural stem cell lineage-specific cannabinoid type-1 receptor regulates neurogenesis and plasticity in the adult mouse hippocampus

2018

Abstract Neural stem cells (NSCs) in the adult mouse hippocampus occur in a specific neurogenic niche, where a multitude of extracellular signaling molecules converges to regulate NSC proliferation as well as fate and functional integration. However, the underlying mechanisms how NSCs react to extrinsic signals and convert them to intracellular responses still remains elusive. NSCs contain a functional endocannabinoid system, including the cannabinoid type-1 receptor (CB1). To decipher whether CB1 regulates adult neurogenesis directly or indirectly in vivo, we performed NSC-specific conditional inactivation of CB1 by using triple-transgenic mice. Here, we show that lack of CB1 in NSCs is su…

Neurovascular EGFL7 regulates adult neurogenesis in the subventricular zone and thereby affects olfactory perception

2016

Adult neural stem cells reside in a specialized niche in the subventricular zone (SVZ). Throughout life they give rise to adult-born neurons in the olfactory bulb (OB), thus contributing to neural plasticity and pattern discrimination. Here, we show that the neurovascular protein EGFL7 is secreted by endothelial cells and neural stem cells (NSCs) of the SVZ to shape the vascular stem-cell niche. Loss of EGFL7 causes an accumulation of activated NSCs, which display enhanced activity and re-entry into the cell cycle. EGFL7 pushes activated NSCs towards quiescence and neuronal progeny towards differentiation. This is achieved by promoting Dll4-induced Notch signalling at the blood vessel-stem …