scholarly journals Reactive, Adult Neurogenesis From Increased Neural Progenitor Cell Proliferation Following Alcohol Dependence in Female Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Natalie N. Nawarawong ◽  
K. Ryan Thompson ◽  
Steven P. Guerin ◽  
Chinchusha Anasooya Shaji ◽  
Hui Peng ◽  
...  

Hippocampal neurodegeneration is a consequence of excessive alcohol drinking in alcohol use disorders (AUDs), however, recent studies suggest that females may be more susceptible to alcohol-induced brain damage. Adult hippocampal neurogenesis is now well accepted to contribute to hippocampal integrity and is known to be affected by alcohol in humans as well as in animal models of AUDs. In male rats, a reactive increase in adult hippocampal neurogenesis has been observed during abstinence from alcohol dependence, a phenomenon that may underlie recovery of hippocampal structure and function. It is unknown whether reactive neurogenesis occurs in females. Therefore, adult female rats were exposed to a 4-day binge model of alcohol dependence followed by 7 or 14 days of abstinence. Immunohistochemistry (IHC) was used to assess neural progenitor cell (NPC) proliferation (BrdU and Ki67), the percentage of increased NPC activation (Sox2+/Ki67+), the number of immature neurons (NeuroD1), and ectopic dentate gyrus granule cells (Prox1). On day seven of abstinence, ethanol-treated females showed a significant increase in BrdU+ and Ki67+ cells in the subgranular zone of the dentate gyrus (SGZ), as well as greater activation of NPCs (Sox2+/Ki67+) into active cycling. At day 14 of abstinence, there was a significant increase in the number of immature neurons (NeuroD1+) though no evidence of ectopic neurogenesis according to either NeuroD1 or Prox1 immunoreactivity. Altogether, these data suggest that alcohol dependence produces similar reactive increases in NPC proliferation and adult neurogenesis. Thus, reactive, adult neurogenesis may be a means of recovery for the hippocampus after alcohol dependence in females.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenna Hourigan ◽  
Spencer D. Balay ◽  
Graydon Yee ◽  
Saloni Sharma ◽  
Qiumin Tan

AbstractNew neurons continuously arise from neural progenitor cells in the dentate gyrus of the adult hippocampus to support ongoing learning and memory formation. To generate functional adult-born neurons, neural progenitor cells proliferate to expand the precursor cell pool and differentiate into neurons. Newly generated cells then undergo postmitotic maturation to migrate to their final destination and develop elaborate dendritic branching, which allows them to receive input signals. Little is known about factors that regulate neuronal differentiation, migration, and dendrite maturation during adult hippocampal neurogenesis. Here, we show that the transcriptional repressor protein capicua (CIC) exhibits dynamic expression in the adult dentate gyrus. Conditional deletion of Cic from the mouse dentate gyrus compromises the adult neural progenitor cell pool without altering their proliferative potential. We further demonstrate that the loss of Cic impedes neuronal lineage development and disrupts dendritic arborization and migration of adult-born neurons. Our study uncovers a previously unrecognized role of CIC in neurogenesis of the adult dentate gyrus.


2019 ◽  
Author(s):  
Shunya Yagi ◽  
Jared E.J. Splinter ◽  
Daria Tai ◽  
Sarah Wong ◽  
Yanhua Wen ◽  
...  

ABSTRACTSex differences exist in the regulation of adult neurogenesis in the hippocampus in response to hormones and cognitive training. Here we investigated the trajectory and maturation rate of adult-born neurons in the dentate gyrus (DG) of male and female rats. Sprague-Dawley rats were perfused two hours, 24 hours, one, two or three weeks after BrdU injection, a DNA synthesis marker that labels dividing progenitor cells and their progeny. Adult-born neurons (BrdU/NeuN-ir) matured faster in males compared to females. Males had a greater density of neural stem cells (Sox2-ir) in the dorsal, but not in the ventral, DG and had higher levels of cell proliferation (Ki67-ir) than non-proestrous females. However, males showed a greater reduction in neurogenesis between one and two weeks after mitosis, whereas females showed similar levels of neurogenesis throughout the weeks. The faster maturation and greater attrition of new neurons in males compared to females suggests greater potential for neurogenesis to respond to external stimuli in males and emphasizes the importance of studying sex on adult hippocampal neurogenesis.Significance StatementPreviously studies examining the characteristics of adult-born neurons in the dentate gyrus have used almost exclusively male subjects. Researchers have assumed the two sexes have a similar maturation and attrition of new neurons in the dentate gyrus of adults. However, this study highlights notable sex differences in the attrition, maturation rate and potential of neurogenesis in the adult hippocampus that has significant implications for the field of neuroplasticity. These findings are important in understanding the relevance of sex differences in the regulation of neurogenesis in the hippocampus in response to stimuli or experience and may have consequences for our understanding of diseases that involve neurodegeneration of the hippocampus, particularly those that involve sex differences, such as Alzheimer’s disease and depression.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Hideo Hagihara ◽  
Tomoyuki Murano ◽  
Koji Ohira ◽  
Miki Miwa ◽  
Katsuki Nakamura ◽  
...  

AbstractIt is agreed upon that adult hippocampal neurogenesis (AHN) occurs in the dentate gyrus (DG) in rodents. However, the existence of AHN in humans, particularly in elderly individuals, remains to be determined. Recently, several studies reported that neural progenitor cells, neuroblasts, and immature neurons were detected in the hippocampus of elderly humans, based on the expressions of putative markers for these cells, claiming that this provides evidence of the persistence of AHN in humans. Herein, we briefly overview the phenomenon that we call “dematuration,” in which mature neurons dedifferentiate to a pseudo-immature status and re-express the molecular markers of neural progenitor cells and immature neurons. Various conditions can easily induce dematuration, such as inflammation and hyper-excitation of neurons, and therefore, the markers for neural progenitor cells and immature neurons may not necessarily serve as markers for AHN. Thus, the aforementioned studies have not presented definitive evidence for the persistence of hippocampal neurogenesis throughout adult life in humans, and we would like to emphasize that those markers should be used cautiously when presented as evidence for AHN. Increasing AHN has been considered as a therapeutic target for Alzheimer’s disease (AD); however, given that immature neuronal markers can be re-expressed in mature adult neurons, independent of AHN, in various disease conditions including AD, strategies to increase the expression of these markers in the DG may be ineffective or may worsen the symptoms of such diseases.


2007 ◽  
Vol 75 (9) ◽  
pp. 4289-4297 ◽  
Author(s):  
Olaf Hoffmann ◽  
Cordula Mahrhofer ◽  
Nina Rueter ◽  
Dorette Freyer ◽  
Bettina Bert ◽  
...  

ABSTRACT Bacterial meningitis is a major infectious cause of neuronal degeneration in the hippocampus. Neurogenesis, a continuous process in the adult hippocampus, could ameliorate such loss. Yet the high rate of sequelae from meningitis suggests that this repair mechanism is inefficient. Here we used a mouse model of nonreplicative bacterial meningitis to determine the impact of transient intracranial inflammation on adult neurogenesis. Experimental meningitis resulted in a net loss of neurons, diminished volume, and impaired neurogenesis in the dentate gyrus for weeks following recovery from the insult. Inducible nitric oxide synthase (iNOS) immunoreactivity was prominent in microglia in nonproliferating areas of the dentate gyrus and hilus region after meningitis induction. Treatment with the specific iNOS inhibitor N6-(1-iminoethyl)-l-lysine restored neurogenesis in experimental meningitis. These data suggest that local central nervous system inflammation in and of itself suppresses adult neurogenesis by affecting both proliferation and neuronal differentiation. Repair of cognitive dysfunction following meningitis could be improved by intervention to interrupt these actively suppressive effects.


2021 ◽  
Author(s):  
M Koehl ◽  
E Ladevèze ◽  
M Montcouquiol ◽  
DN Abrous

AbstractDecline in episodic memory is one of the hallmarks of aging and represents one of the most important health problems facing western societies. A key structure in episodic memory is the hippocampal formation and the dentate gyrus in particular, as the continuous production of new dentate granule neurons in this brain region was found to play a crucial role in memory and in age-related decline in memory. As such, understanding the molecular processes that regulate the relationship between adult neurogenesis and aging of memory function holds great therapeutic potential. Recently, we found that Vang-gogh like 2 (Vangl2), a core component of the planar cell polarity signaling pathway, is enriched in the dentate gyrus of adult mice. In this context, we sought to evaluate the involvement of this effector of the Wnt/PCP pathway in both adult neurogenesis and memory abilities in adult and middle-aged mice. Using a heterozygous mouse model carrying a dominant negative mutation in Vangl2 gene, we show that alteration in Vangl2 expression decreases the survival of adult-born granule cells and advances the onset of decrease in cognitive flexibility. Inability of mutant mice to erase old irrelevant information to the benefit of new relevant ones highlights a key role of Vangl2 in interference-based forgetting. Taken together, our findings show for the first that Vangl2 activity may constitute an interesting target to prevent age-related decline in hippocampal plasticity and memory.


2019 ◽  
Vol 129 ◽  
pp. 239-248 ◽  
Author(s):  
Wonjong Lee ◽  
Jung-Hyun Cho ◽  
Yujeong Lee ◽  
Seulah Lee ◽  
Dae Hyun Kim ◽  
...  

2021 ◽  
Author(s):  
Bryon M Smith ◽  
Angela I Saulsbery ◽  
Patricia Sarchet ◽  
Nidhi Devasthali ◽  
Dalia Einstein ◽  
...  

Inducible Cre recombinase facilitates temporal control of genetic recombination in numerous transgenic model systems, a feature which has made it a popular tool for studies of adult neurogenesis. One of the most common forms of inducible Cre, CreERT2, requires activation by the synthetic estrogen tamoxifen (TAM) to initiate recombination of LoxP-flanked sequences. To date, most studies deliver TAM via intraperitoneal injection. But the introduction of TAM-infused commercial chows has recently expanded the possible modes of TAM delivery. Despite the widespread use of TAM-inducible genetic models in adult neurogenesis research, the comparative efficiency and off-target effects of TAM administration protocols is surprisingly infrequently studied. Here we compare a standard, 5 day TAM injection regimen with voluntary consumption of TAM-infused chow. First, we used adult NestinCreERT2;Rosa-LoxP-STOP-LoxP-EYFP reporter mice to show that 2 weeks of TAM chow and 5 days of injections led to LoxP recombination in a similar phenotypic population of neural stem and progenitor cells in the adult dentate gyrus. However, TAM chow resulted in substantially less overall recombination than injections. TAM administration also altered adult neurogenesis, but in different ways depending on administration route: TAM injection disrupted neural progenitor cell proliferation 3 weeks after TAM, whereas TAM chow increased neuronal differentiation of cells generated during the diet period. These findings provide guidance for selection of TAM administration route and appropriate controls in adult neurogenesis studies using TAM-inducible Cre mice. They also highlight the need for better understanding of off-target effects of TAM in other neurological processes and organ systems.


2021 ◽  
Vol 22 (22) ◽  
pp. 12163
Author(s):  
Hrvoje Omrčen ◽  
Sanja Zoričić Cvek ◽  
Lara Batičić ◽  
Sandra Šućurović ◽  
Tanja Grubić Kezele

BMPs regulate synovial quiescence and adult neurogenesis in the hippocampus in non-stress conditions. However, changes in BMP expression that are induced by inflammation during rheumatoid arthritis (RA) have not yet been reported. Here, we show that signalling with synovial BMPs (BMP-4 and -7) mediates the effect of systemic inflammation on adult neurogenesis in the hippocampus during pristane-induced arthritis (PIA) in Dark Agouti (DA) rats, an animal model of RA. Moreover, we show gender differences in BMP expressions and their antagonists (Noggin and Gremlin) during PIA and their correlations with the clinical course and IL-17A and TNF-α levels in serum. Our results indicate gender differences in the clinical course, where male rats showed earlier onset and earlier recovery but a worse clinical course in the first two phases of the disease (onset and peak), which correlates with the initial increase of serum IL-17A level. The clinical course of the female rats worsened in remission. Their prolonged symptoms could be a reflection of an increased TNF-α level in serum during remission. Synovial inflammation was greater in females in PIA-remission with greater synovial BMP and antagonist expressions. More significant correlations between serum cytokines (IL-17A and TNF-α), and synovial BMPs and their antagonists were found in females than in males. On the other hand, males showed an increase in hippocampal BMP-4 expression during the acute phase, but both genders showed a decrease in antagonist expressions during PIA in general. Both genders showed a decrease in the number of Ki-67+ and SOX-2+ and DCX+ cells and in the ratio of DCX+ to Ki67+ cells in the dentate gyrus during PIA. However, in PIA remission, females showed a faster increase in the number of Ki67+, SOX-2+, and DCX+ cells and a faster increase in the DCX/Ki67 ratio than males. Both genders showed an increase of hippocampal BMP-7 expression during remission, although males constantly showed greater BMP-7 expression at all time points. Our data show that gender differences exist in the BMP expressions in the periphery–hippocampus axis and in the IL-17A and TNF-α levels in serum, which could imply differences in the mechanisms for the onset and progression of the disease, the clinical course severity, and adult neurogenesis with subsequent neurological complications between genders.


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