scholarly journals Sex Differences in Maturation and Attrition of Adult Neurogenesis in the Hippocampus

2019 ◽  
Author(s):  
Shunya Yagi ◽  
Jared E.J. Splinter ◽  
Daria Tai ◽  
Sarah Wong ◽  
Yanhua Wen ◽  
...  
Keyword(s):  
Sex Differences ◽  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Female Rats ◽  
Sprague Dawley ◽  
Male And Female Rats ◽  
Maturation Rate ◽  
Adult Born Neurons

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.

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 ◽  
...  
Keyword(s):  
Alcohol Dependence ◽  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Progenitor Cell ◽  
Neural Progenitor Cell ◽  
Neural Progenitor ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Female Rats ◽  
Immature Neurons

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.

scholarly journals Intact memory for local and distal cues in male and female rats that lack adult neurogenesis

2018 ◽  
Author(s):  
Desiree R Seib ◽  
Erin Chahley ◽  
Oren Princz-Lebel ◽  
Jason S Snyder
Keyword(s):  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Granule Cells ◽  
Sensory Information ◽  
Female Rats ◽  
Male Rats ◽  
Separation Function ◽  
Male And Female ◽  
Male And Female Rats ◽  
Adult Born Neurons

ABSTRACTThe dentate gyrus is essential for remembering the fine details of experiences that comprise episodic memory. Dentate gyrus granule cells receive highly-processed sensory information and are hypothesized to perform a pattern separation function, whereby similar sensory inputs are transformed into orthogonal neural representations. Behaviorally, this is believed to enable distinct memory for highly interfering stimuli. Since the dentate gyrus is comprised of a large number of adult-born neurons, which have unique synaptic wiring and neurophysiological firing patterns, it has been proposed that neurogenesis may contribute to this process in unique ways. Some behavioral evidence exists to support this role, whereby neurogenesis-deficient rodents are impaired at discriminating the fine visuospatial details of experiences. However, the extent to which newborn neurons contribute to dentate gyrus-dependent learning tasks is unclear. Furthermore, since most studies of dentate gyrus function are conducted in male rats, little is known about how females perform in similar situations, and whether there might be sex differences in the function of adult neurogenesis. To address these issues, we examined spatial discrimination memory in transgenic male and female rats that lacked adult neurogenesis. The first task probed memory for the position of local objects in an open field, assessed by behavioral responses to novel object locations. The second task examined memory for distal environmental cues. All rats were able to successfully discriminate local and distal cue changes. Males and females also performed comparably, although females displayed higher levels of rearing and locomotion. Collectively, our results indicate that rats are capable of learning about local and distal cues in the absence of adult neurogenesis.

scholarly journals The intellectual disability PAK3 R67C mutation impacts cognitive functions and adult hippocampal neurogenesis

2020 ◽  
Vol 29 (12) ◽  
pp. 1950-1968
Author(s):  
Charlotte Castillon ◽  
Laurine Gonzalez ◽  
Florence Domenichini ◽  
Sandrine Guyon ◽  
Kevin Da Silva ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Mouse Model ◽  
Spatial Memory ◽  
Adult Neurogenesis ◽  
Hippocampal Neurons ◽  
Memory Task ◽  
Clinical Signs ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Adult Born Neurons

Abstract The link between mutations associated with intellectual disability (ID) and the mechanisms underlying cognitive dysfunctions remains largely unknown. Here, we focused on PAK3, a serine/threonine kinase whose gene mutations cause X-linked ID. We generated a new mutant mouse model bearing the missense R67C mutation of the Pak3 gene (Pak3-R67C), known to cause moderate to severe ID in humans without other clinical signs and investigated hippocampal-dependent memory and adult hippocampal neurogenesis. Adult male Pak3-R67C mice exhibited selective impairments in long-term spatial memory and pattern separation function, suggestive of altered hippocampal neurogenesis. A delayed non-matching to place paradigm testing memory flexibility and proactive interference, reported here as being adult neurogenesis-dependent, revealed a hypersensitivity to high interference in Pak3-R67C mice. Analyzing adult hippocampal neurogenesis in Pak3-R67C mice reveals no alteration in the first steps of adult neurogenesis, but an accelerated death of a population of adult-born neurons during the critical period of 18–28 days after their birth. We then investigated the recruitment of hippocampal adult-born neurons after spatial memory recall. Post-recall activation of mature dentate granule cells in Pak3-R67C mice was unaffected, but a complete failure of activation of young DCX + newborn neurons was found, suggesting they were not recruited during the memory task. Decreased expression of the KCC2b chloride cotransporter and altered dendritic development indicate that young adult-born neurons are not fully functional in Pak3-R67C mice. We suggest that these defects in the dynamics and learning-associated recruitment of newborn hippocampal neurons may contribute to the selective cognitive deficits observed in this mouse model of ID.

scholarly journals Inhibiting adult neurogenesis differentially affects spatial learning in females and males

2021 ◽  
Author(s):  
Timothy P O'Leary ◽  
Baran Askari ◽  
Bonnie Lee ◽  
Kathryn Darby ◽  
Cypress Knudson ◽  
...  
Keyword(s):  
Sex Differences ◽  
Search Strategy ◽  
Cold Water ◽  
Mossy Fiber ◽  
Dorsal Hippocampus ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Early Gene ◽  
Males And Females ◽  
Adult Born Neurons

Adult hippocampal neurogenesis has been implicated in the spatial processing functions of the hippocampus but ablating neurogenesis does not consistently lead to behavioral deficits in spatial tasks. Parallel studies have shown that adult-born neurons also regulate behavioral responses to stressful and aversive stimuli. We therefore hypothesized that spatial functions of adult-born neurons may be more prominent under conditions of stress, and may differ between males and females given established sex differences in stress responding. To test this we trained intact and neurogenesis-deficient rats in the spatial water maze at temperatures that vary in their degree of aversiveness. At standard temperatures (25°C) ablating neurogenesis did not alter learning and memory in either sex, consistent with prior work. However, in cold water (16°C), ablating neurogenesis had divergent sex-dependent effects: relative to intact rats, male neurogenesis-deficient rats were slower to escape and female neurogenesis-deficient rats were faster. Neurogenesis promoted temperature-related changes in search strategy in females, but it promoted search strategy stability in males. Females displayed greater recruitment of the dorsal hippocampus than males, particularly at 16°C. However, blocking neurogenesis did not alter activity-dependent immediate-early gene expression in either sex. Finally, morphological analyses of retrovirally-labelled neurons revealed greater experience-dependent plasticity in new neurons in males. Neurons had comparable morphology in untrained rats but 16°C training increased spine density, and 25°C training caused shrinkage of mossy fiber presynaptic terminals, specifically in males. Collectively, these findings indicate that neurogenesis functions in memory are prominent under conditions of stress, they provide the first evidence for sex differences in the behavioral function of newborn neurons, and they suggest possibly distinct roles for neurogenesis in cognition and mental health in males and females.

scholarly journals Pneumococcal Cell Wall-Induced Meningitis Impairs Adult Hippocampal Neurogenesis

2007 ◽  
Vol 75 (9) ◽  
pp. 4289-4297 ◽  
Author(s):  
Olaf Hoffmann ◽  
Cordula Mahrhofer ◽  
Nina Rueter ◽  
Dorette Freyer ◽  
Bettina Bert ◽  
...  
Keyword(s):  
Bacterial Meningitis ◽  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Neuronal Degeneration ◽  
Continuous Process ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
High Rate ◽  
Induction Treatment ◽  
The Impact

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.

scholarly journals Vangl2, a core component of the WNT/PCP pathway, regulates adult hippocampal neurogenesis and age-related decline in cognitive flexibility

2021 ◽  
Author(s):  
M Koehl ◽  
E Ladevèze ◽  
M Montcouquiol ◽  
DN Abrous
Keyword(s):  
Episodic Memory ◽  
Dentate Gyrus ◽  
Cognitive Flexibility ◽  
Adult Neurogenesis ◽  
Continuous Production ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Core Component ◽  
Dominant Negative Mutation ◽  
Age Related

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.

scholarly journals Androgens enhance adult hippocampal neurogenesis in males but not females in an age-dependent manner

2019 ◽  
Author(s):  
Paula Duarte-Guterman ◽  
Dwayne K. Hamson ◽  
Steven R. Wainwright ◽  
Carmen Chow ◽  
Jessica Chaiton ◽  
...  
Keyword(s):  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Female Rats ◽  
Male Rats ◽  
Dependent Manner ◽  
Middle Aged ◽  
Young Males ◽  
Neuron Survival ◽  
Male And Female Rats ◽  
Age Dependent

AbstractAndrogens (testosterone and dihydrotestosterone) increase adult hippocampal neurogenesis by increasing new neuron survival in male rats and mice via an androgen receptor pathway, but it is not known whether androgens regulate neurogenesis in females and whether the effect is age-dependent. We investigated the effects of dihydrotestosterone, a potent androgen, on neurogenesis in adult and middle-aged males and females. Rats were gonadectomized and injected with the DNA synthesis marker, bromodeoxyuridine (BrdU). The following day rats began receiving daily injections of oil or DHT for 30 days. We evaluated cell proliferation (Ki67) and new neuron survival (BrdU and BrdU/NeuN) in the hippocampus of male and female rats using immunohistochemistry. As expected, DHT increased new neuron survival in young males but surprisingly not in middle-aged male rats. In females, DHT did not significantly affect adult neurogenesis in young or middle age. Our results indicate that DHT regulates adult hippocampal neurogenesis in a sex- and age-dependent manner.

scholarly journals Androgens Increase Survival of Adult-Born Neurons in the Dentate Gyrus by an Androgen Receptor-Dependent Mechanism in Male Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (9) ◽  
pp. 3294-3304 ◽  
Author(s):  
D. K. Hamson ◽  
S. R. Wainwright ◽  
J. R. Taylor ◽  
B. A. Jones ◽  
N. V. Watson ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Dentate Gyrus ◽  
Adult Neurogenesis ◽  
Hippocampal Neurogenesis ◽  
Adult Brain ◽  
Male Rats ◽  
Male Rat ◽  
Testicular Feminization ◽  
Wild Type ◽  
Adult Born Neurons

Gonadal steroids are potent regulators of adult neurogenesis. We previously reported that androgens, such as testosterone (T) and dihydrotestosterone (DHT), but not estradiol, increased the survival of new neurons in the dentate gyrus of the male rat. These results suggest androgens regulate hippocampal neurogenesis via the androgen receptor (AR). To test this supposition, we examined the role of ARs in hippocampal neurogenesis using 2 different approaches. In experiment 1, we examined neurogenesis in male rats insensitive to androgens due to a naturally occurring mutation in the gene encoding the AR (termed testicular feminization mutation) compared with wild-type males. In experiment 2, we injected the AR antagonist, flutamide, into castrated male rats and compared neurogenesis levels in the dentate gyrus of DHT and oil-treated controls. In experiment 1, chronic T increased hippocampal neurogenesis in wild-type males but not in androgen-insensitive testicular feminization mutation males. In experiment 2, DHT increased hippocampal neurogenesis via cell survival, an effect that was blocked by concurrent treatment with flutamide. DHT, however, did not affect cell proliferation. Interestingly, cells expressing doublecortin, a marker of immature neurons, did not colabel with ARs in the dentate gyrus, but ARs were robustly expressed in other regions of the hippocampus. Together these studies provide complementary evidence that androgens regulate adult neurogenesis in the hippocampus via the AR but at a site other than the dentate gyrus. Understanding where in the brain androgens act to increase the survival of new neurons in the adult brain may have implications for neurodegenerative disorders.

scholarly journals Capicua regulates the development of adult-born neurons in the hippocampus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenna Hourigan ◽  
Spencer D. Balay ◽  
Graydon Yee ◽  
Saloni Sharma ◽  
Qiumin Tan
Keyword(s):  
Dentate Gyrus ◽  
Progenitor Cells ◽  
Neural Progenitor Cells ◽  
Neural Progenitor Cell ◽  
Neural Progenitor ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Proliferative Potential ◽  
Cell Pool ◽  
Adult Born Neurons

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.

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