Search results for "Subgranular zone"

Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.

2018

New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus(1-5). This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease(6-10). In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day(11), whereas other studies find many fewer putative new neurons(12-14). Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal …

Stable and Efficient Genetic Modification of Cells in the Adult Mouse V-SVZ for the Analysis of Neural Stem Cell Autonomous and Non-autonomous Effects

2016

Relatively quiescent somatic stem cells support life-long cell renewal in most adult tissues. Neural stem cells in the adult mammalian brain are restricted to two specific neurogenic niches: the subgranular zone of the dentate gyrus in the hippocampus and the ventricular-subventricular zone (V-SVZ; also called subependymal zone or SEZ) in the walls of the lateral ventricles. The development of in vivo gene transfer strategies for adult stem cell populations (i.e. those of the mammalian brain) resulting in long-term expression of desired transgenes in the stem cells and their derived progeny is a crucial tool in current biomedical and biotechnological research. Here, a direct in vivo method …

Amyotrophic lateral sclerosis modifies progenitor neural proliferation in adult classic neurogenic brain niches.

2017

Background Adult neurogenesis persists through life at least in classic neurogenic niches. Neurogenesis has been previously described as reduced in neurodegenerative diseases. There is not much knowledge about is adult neurogenesis is or not modified in amyotrophy lateral sclerosis (ALS). All previous publications has studied the ALS SOD1 (superoxide dismutase) transgenic mouse model. The purpose of this study is to examine the process of adult neurogenesis in classic niches (subventricular zone [SVZ] and subgranular zone [SGZ] of the dentate gyrus) in patients with amyotrophic lateral sclerosis (ALS), both with (ALS-FTD) and without associated frontotemporal dementia (FTD). Methods We stud…

2018

In mammalian species, including humans, the hippocampal dentate gyrus (DG) is a primary region of adult neurogenesis. Aberrant adult hippocampal neurogenesis is associated with neurological pathologies. Understanding the cellular mechanisms controlling adult hippocampal neurogenesis is expected to open new therapeutic strategies for mental disorders. Microglia is intimately associated with neural progenitor cells in the hippocampal DG and has been implicated, under varying experimental conditions, in the control of the proliferation, differentiation and survival of neural precursor cells. But the underlying mechanisms remain poorly defined. Using fluorescent in situ hybridization we show th…

Hypocellularity in the murine model for Down Syndrome Ts65Dn is not affected by adult neurogenesis

2016

Down syndrome (DS) is caused by the presence of an extra copy of the chromosome 21 and it is the most common aneuploidy producing intellectual disability. Neural mechanisms underlying this alteration may include defects in the formation of neuronal networks, information processing and brain plasticity. The murine model for DS, Ts65Dn, presents reduced adult neurogenesis. This reduction has been suggested to underlie the hypocellularity of the hippocampus as well as the deficit in olfactory learning in the Ts65Dn mice. Similar alterations have also been observed in individuals with DS. To determine whether the impairment in adult neurogenesis is, in fact, responsible for the hypocellularity …

Dlk1 dosage regulates hippocampal neurogenesis and cognition

2021

Significance Generation of new neurons occurs normally in the adult brain in two locations: the subventricular zone (SVZ) in the walls of the lateral ventricles and the subgranular zone (SGZ) in the dentate gyrus (DG) of the hippocampus. Neurogenesis in the adult hippocampus has been implicated in cognitive functions such as learning, memory, and recovery of stress response. Imprinted genes are highly prevalent in the brain and have adult and developmental important functions. Genetic deletion of the imprinted gene Dlk1 from either parental allele shows that DLK1 is a key mediator of quiescence in adult hippocampal NSCs. Additionally, Dlk1 is exquisitely dosage sensitive in the brain with p…

Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the a…

2015

Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of his…

The FGF-2/FGFRs neurotrophic system promotes neurogenesis in the adult brain.

2009

Neurogenesis occurs in two regions of the adult brain, namely, the subventricular zone (SVZ) throughout the wall of the lateral ventricle and the subgranular zone (SGZ) of the dentate gyrus (DG) in hippocampal formation. Adult neurogenesis requires several neurotrophic factors to sustain and regulate the proliferation and differentiation of the adult stem cell population. In the present review, we examine the cellular and functional aspects of a trophic system mediated by fibroblast growth factor-2 (FGF-2) and its receptors (FGFRs) related to neurogenesis in the SVZ and SGZ of the adult rat brain. In the SVZ, FGF-2 is expressed in GFAP-positive cells of SVZ but is not present in proliferati…

Cell types, lineage, and architecture of the germinal zone in the adult dentate gyrus

2004

New neurons continue to be born in the subgranular zone (SGZ) of the dentate gyrus in the hippocampus of adult mammals, including humans. Previous work has shown that astrocytes function as the progenitors of these new neurons through immature intermediate D cells. In the first part of the present study, we determined the structure of each of these progenitors and how they are organized in three dimensions. Serial-section reconstructions of the SGZ, using confocal and electron microscopy demonstrate that SGZ astrocytes form baskets that hold clusters of D cells, largely insulating them from the hilus. Two types of glial fibrillary acidic protein-expressing astrocytes (radial and horizontal)…

Dual effects of increased glycogen synthase kinase-3β activity on adult neurogenesis

2013

Adult neurogenesis, the generation of new neurons during the adulthood, is a process controlled by several kinases and phosphatases among which GSK3β exerts important functions. This protein is particularly abundant in the central nervous system, and its activity deregulation is believed to play a key role in chronic disorders such as Alzheimer's disease. Previously, we reported that in vivo overexpression of GSK3β (Tet/GSK3β mice) causes alterations in adult neurogenesis, leading to a depletion of the neurogenic niches. Here, we have further characterized those alterations, finding a delay in the switching-off of doublecortin marker as well as changes in the survival and death rates of imm…