1
|
Kapri D, Pradhan A, Vuruputuri RM, Vaidya VA. Sex differences in the influence of adult-onset hypothyroidism on hippocampal progenitor survival and neuronal differentiation in mice. J Neuroendocrinol 2024:e13453. [PMID: 39360641 DOI: 10.1111/jne.13453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 08/29/2024] [Accepted: 09/16/2024] [Indexed: 10/04/2024]
Abstract
The ongoing production of newborn neurons in the adult hippocampus is reported to be sensitive to perturbations of thyroid hormone signaling, in male rats and mice. Here, we examined whether the neurogenic changes evoked by adult-onset hypothyroidism exhibit sex differences, using male and female C57BL/6N mice. We assessed the impact of goitrogen-induced, adult-onset hypothyroidism on the postmitotic survival and differentiation of hippocampal progenitors in male and female mice. Adult-onset hypothyroidism evoked a significant decline in the postmitotic survival and neuronal differentiation of adult-born progenitors within the dentate gyrus hippocampal subfield of male, but not female, mice. We observed a significant decrease in the number of immature neurons within the hippocampi of adult-onset hypothyroid male mice, whereas adult-onset hypothyroidism evoked by goitrogens using the same treatment paradigms did not evoke any change in immature neuron number in female mice. Gene expression analysis within the hippocampi of euthyroid male and female mice revealed sex-dependent, differential expression of thyroid hormone receptor genes, as well as genes linked to thyroid hormone metabolism and transport. Collectively, our findings highlight sex differences in the influence of goitrogen-induced, adult-onset hypothyroidism on hippocampal neurogenesis, with male, but not female, mice exhibiting a decline in postmitotic hippocampal progenitor survival and neuronal differentiation. These findings underscore the importance of sex as a vital variable when considering the impact of thyroid hormone signaling on the adult hippocampal neurogenic niche.
Collapse
Affiliation(s)
- Darshana Kapri
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Amartya Pradhan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Ratna Mahathi Vuruputuri
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| |
Collapse
|
2
|
Fauser M, Payonk JP, Weber H, Statz M, Winter C, Hadar R, Appali R, van Rienen U, Brandt MD, Storch A. Subthalamic nucleus but not entopeduncular nucleus deep brain stimulation enhances neurogenesis in the SVZ-olfactory bulb system of Parkinsonian rats. Front Cell Neurosci 2024; 18:1396780. [PMID: 38746080 PMCID: PMC11091264 DOI: 10.3389/fncel.2024.1396780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 04/08/2024] [Indexed: 05/16/2024] Open
Abstract
Introduction Deep brain stimulation (DBS) is a highly effective treatment option in Parkinson's disease. However, the underlying mechanisms of action, particularly effects on neuronal plasticity, remain enigmatic. Adult neurogenesis in the subventricular zone-olfactory bulb (SVZ-OB) axis and in the dentate gyrus (DG) has been linked to various non-motor symptoms in PD, e.g., memory deficits and olfactory dysfunction. Since DBS affects several of these non-motor symptoms, we analyzed the effects of DBS in the subthalamic nucleus (STN) and the entopeduncular nucleus (EPN) on neurogenesis in 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rats. Methods In our study, we applied five weeks of continuous bilateral STN-DBS or EPN-DBS in 6-OHDA-lesioned rats with stable dopaminergic deficits compared to 6-OHDA-lesioned rats with corresponding sham stimulation. We injected two thymidine analogs to quantify newborn neurons early after DBS onset and three weeks later. Immunohistochemistry identified newborn cells co-labeled with NeuN, TH and GABA within the OB and DG. As a putative mechanism, we simulated the electric field distribution depending on the stimulation site to analyze direct electric effects on neural stem cell proliferation. Results STN-DBS persistently increased the number of newborn dopaminergic and GABAergic neurons in the OB but not in the DG, while EPN-DBS does not impact neurogenesis. These effects do not seem to be mediated via direct electric stimulation of neural stem/progenitor cells within the neurogenic niches. Discussion Our data support target-specific effects of STN-DBS on adult neurogenesis, a putative modulator of non-motor symptoms in Parkinson's disease.
Collapse
Affiliation(s)
- Mareike Fauser
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Jan Philipp Payonk
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
| | - Hanna Weber
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Meike Statz
- Department of Neurology, University of Rostock, Rostock, Germany
| | - Christine Winter
- Department of Psychiatry and Neurosciences, Charité University Medicine Berlin, Berlin, Germany
| | - Ravit Hadar
- Department of Psychiatry and Neurosciences, Charité University Medicine Berlin, Berlin, Germany
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Department of Ageing of Individuals and Society, University of Rostock, Rostock, Germany
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Department of Ageing of Individuals and Society, University of Rostock, Rostock, Germany
- Department of Life, Light and Matter, University of Rostock, Rostock, Germany
| | - Moritz D. Brandt
- Department of Neurology, University Hospital Carl Gustav Carus Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Dresden, Germany
| | - Alexander Storch
- Department of Neurology, University of Rostock, Rostock, Germany
- German Center for Neurodegenerative Diseases (DZNE) Rostock/Greifswald, Rostock, Germany
| |
Collapse
|
3
|
Martínez-Canabal A, López-Oropeza G, Sotres-Bayón F. Hippocampal neurogenesis facilitates cognitive flexibility in a fear discrimination task. Front Behav Neurosci 2024; 17:1331928. [PMID: 38282713 PMCID: PMC10813213 DOI: 10.3389/fnbeh.2023.1331928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/18/2023] [Indexed: 01/30/2024] Open
Abstract
Hippocampal neurogenesis, the continuous creation of new neurons in the adult brain, influences memory, regulates the expression of defensive responses to threat (fear), and cognitive processes like pattern separation and behavioral flexibility. One hypothesis proposes that neurogenesis promotes cognitive flexibility by degrading established memories and promoting relearning. Yet, empirical evidence on its role in fear discrimination tasks is scarce. In this study, male rats were initially trained to differentiate between two similar environments, one associated with a threat. Subsequently, we enhanced neurogenesis through environmental enrichment and memantine treatments. We then reversed the emotional valence of these contexts. In both cases, neurogenesis improved the rats' ability to relearn the aversive context. Interestingly, we observed increased hippocampal activity, and decreased activity in the prelimbic cortex and lateral habenula, while the infralimbic cortex remained unchanged, suggesting neurogenesis-induced plasticity changes in this brain network. Moreover, when we pharmacologically inhibited the increased neurogenesis with Methotrexate, rats struggled to relearn context discrimination, confirming the crucial role of neurogenesis in this cognitive process. Overall, our findings highlight neurogenesis's capacity to facilitate changes in fear discrimination and emphasize the involvement of a prefrontal-hippocampal-habenula mechanism in this process. This study emphasizes the intricate relationship between hippocampal neurogenesis, cognitive flexibility, and the modulation of fear-related memories.
Collapse
Affiliation(s)
- Alonso Martínez-Canabal
- Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
| | - Grecia López-Oropeza
- Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
- Graduate Program in Biological Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
| | - Francisco Sotres-Bayón
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
| |
Collapse
|
4
|
Tsao CH, Wu KY, Su NC, Edwards A, Huang GJ. The influence of sex difference on behavior and adult hippocampal neurogenesis in C57BL/6 mice. Sci Rep 2023; 13:17297. [PMID: 37828065 PMCID: PMC10570284 DOI: 10.1038/s41598-023-44360-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 10/06/2023] [Indexed: 10/14/2023] Open
Abstract
Animal models have been used extensively in in vivo studies, especially within the biomedical field. Traditionally, single-sex studies, mostly males, are used to avoid any potential confounding variation caused by sex difference and the female estrous cycle. Historically, female animal subjects are believed to exhibit higher variability, and this could increase the statistical power needed to test a hypothesis. This study sets out to evaluate whether a sex difference does exist in mouse behavior, and whether female mice featured higher variability. We assessed the sensorimotor skills, anxiety-like behavior, depression-like behavior, and cognitive abilities of mice through a series of commonly used behavioral tests. Except for the stronger grip force and lower tactile sensory sensitivity detected in male mice, there was no significant difference between males and females in other tests. Furthermore, immunolabeling of neurogenesis markers suggested no significant difference between sexes in adult hippocampal neurogenesis. Within group variances were equivalent; females did not exhibit higher variability than males. However, the overall negative results could be due to the limitation of small sample size. In conclusion, our study provides evidence that sex difference in mice does not significantly influence these commonly used behavioral tests nor adult neurogenesis under basal conditions. We suggest that female mice could also be considered for test inclusion in future experiment design.
Collapse
Affiliation(s)
- Chi-Hui Tsao
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
| | - Kuan-Yu Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan
| | - Nicole Ching Su
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 33302, Taiwan
| | - Andrew Edwards
- Department of Psychiatry, Dykebar Hospital, National Health Service Greater Glasgow and Clyde, Paisley, PA2 7DE, Scotland
| | - Guo-Jen Huang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan.
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 33302, Taiwan.
- Department of Neurology, Chang Gung Memorial Hospital-Linkou Medical Center, Taoyuan, 333, Taiwan.
- Molecular Medicine Research Center, Chang Gung University, Taoyuan, 333, Taiwan.
| |
Collapse
|
5
|
Gallardo-Caballero M, Rodríguez-Moreno CB, Álvarez-Méndez L, Terreros-Roncal J, Flor-García M, Moreno-Jiménez EP, Rábano A, Llorens-Martín M. Prolonged fixation and post-mortem delay impede the study of adult neurogenesis in mice. Commun Biol 2023; 6:978. [PMID: 37741930 PMCID: PMC10517969 DOI: 10.1038/s42003-023-05367-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 09/15/2023] [Indexed: 09/25/2023] Open
Abstract
Adult hippocampal neurogenesis (AHN) gives rise to new neurons throughout life. This phenomenon takes place in more than 120 mammalian species, including humans, yet its occurrence in the latter was questioned after one study proposed the putative absence of neurogenesis markers in the adult human hippocampus. In this regard, we showed that prolonged fixation impedes the visualization of Doublecortin+ immature neurons in this structure, whereas other authors have suggested that a dilated post-mortem delay (PMD) underlies these discrepancies. Nevertheless, the individual and/or additive contribution of fixation and the PMD to the detection (or lack thereof) of other AHN markers has not been studied to date. To address this pivotal question, we used a tightly controlled experimental design in mice, which allowed the dissection of the relative contribution of the aforementioned factors to the visualization of markers of individual AHN stages. Fixation time emerged as the most prominent factor globally impeding the study of this process in mice. Moreover, the visualization of other particularly sensitive epitopes was further prevented by prolonged PMD. These results are crucial to disambiguate current controversies related to the occurrence of AHN not only in humans but also in other mammalian species.
Collapse
Affiliation(s)
- M Gallardo-Caballero
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - C B Rodríguez-Moreno
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - L Álvarez-Méndez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Terreros-Roncal
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - M Flor-García
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - E P Moreno-Jiménez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - M Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain.
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain.
| |
Collapse
|
6
|
Portero-Tresserra M, Galofré-López N, Pallares E, Gimenez-Montes C, Barcia C, Granero R, Rojic-Becker D, Vale-Martínez A, Martí-Nicolovius M, Guillazo-Blanch G. Effects of Caloric Restriction on Spatial Object Recognition Memory, Hippocampal Neuron Loss and Neuroinflammation in Aged Rats. Nutrients 2023; 15:nu15071572. [PMID: 37049417 PMCID: PMC10096994 DOI: 10.3390/nu15071572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/14/2023] Open
Abstract
Age-related neurobiological changes significantly affect hippocampal structure and function, such that the main cognitive impairments associated with aging are related to the integrity of this brain structure, including the deterioration in spatial object recognition (SOR) memory. Previous studies have shown that intrinsic factors such as neuroinflammation, as well as lifestyle factors such as diet, can affect aging-associated brain functions and cognitive performance. In this regard, caloric restriction (CR) produces beneficial effects on health and life expectancy, although its ability to slow down age-dependent effects on cognitive decline and hippocampus (HPC) functioning remains unclear. Therefore, we set out to evaluate the effects of CR on SOR memory in aged male Wistar rats, as well as those on hippocampal neuron loss, neurogenesis and inflammation. The data show that CR in aged rats attenuates the decline in SOR memory, age-associated hippocampal neuron loss, and age-dependent microglial activation. Furthermore, we found a significant reduction in neurogenesis in the dentate gyrus of the old animals relative to adult rats. These findings support the positive effect of CR on SOR memory, suggesting that it dampens hippocampal neuronal loss and reduces proinflammatory activity.
Collapse
Affiliation(s)
- Marta Portero-Tresserra
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Neus Galofré-López
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Elisabet Pallares
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Claudia Gimenez-Montes
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Carlos Barcia
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Roser Granero
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Ciber Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Psychoneurobiology of Eating and Addictive Behaviors Group, Neurosciences Programme, Bellvitge Institute for Biomedical Research (IDIBELL), 08908 Barcelona, Spain
| | - Divka Rojic-Becker
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Anna Vale-Martínez
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Margarita Martí-Nicolovius
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Gemma Guillazo-Blanch
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| |
Collapse
|
7
|
Vesicular Zinc Modulates Cell Proliferation and Survival in the Developing Hippocampus. Cells 2023; 12:cells12060880. [PMID: 36980221 PMCID: PMC10047515 DOI: 10.3390/cells12060880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
In the brain, vesicular zinc, which refers to a subset of zinc that is sequestered into synaptic vesicles by zinc transporter 3 (ZnT3), has extensive effects on neuronal signalling and modulation. Vesicular zinc-focused research has mainly been directed to its role in the hippocampus, particularly in adult neurogenesis. However, whether vesicular zinc is involved in modulating neurogenesis during the early postnatal period has been less studied. As a first step to understanding this, we used ZnT3 knockout (KO) mice, which lack ZnT3 and, thus, vesicular zinc, to evaluate cell proliferation at three different age points spanning postnatal development (P6, P14, and P28). The survival and the neuronal phenotype of these cells was also assessed in adulthood. We found that male ZnT3 KO mice exhibited lower rates of cell proliferation at P14, but a greater number of these cells survived to adulthood. Additionally, significantly more cells labelled on P6 survived to adulthood in male and female ZnT3 KO mice. We also found sex-dependent differences, whereby male mice showed higher levels of cell proliferation at P28, as well as higher levels of cell survival for P14-labelled cells, compared to female mice. However, female mice showed greater percentages of neuronal differentiation for P14-labelled cells. Finally, we found significant effects of age of BrdU injections on cell proliferation, survival, and neuronal differentiation. Collectively, our results suggest that the loss of vesicular zinc affects normal proliferation and survival of cells born at different age points during postnatal development and highlight prominent sex- and age-dependent differences. Our findings provide the foundation for future studies to further probe the role of vesicular zinc in the modulation of developmental neurogenesis.
Collapse
|
8
|
Rocks D, Kundakovic M. Hippocampus-based behavioral, structural, and molecular dynamics across the estrous cycle. J Neuroendocrinol 2023; 35:e13216. [PMID: 36580348 PMCID: PMC10050126 DOI: 10.1111/jne.13216] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/19/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022]
Abstract
The activity of neurons in the rodent hippocampus contributes to diverse behaviors, with the activity of ventral hippocampal neurons affecting behaviors related to anxiety and emotion regulation, and the activity of dorsal hippocampal neurons affecting performance in learning- and memory-related tasks. Hippocampal cells also express receptors for ovarian hormones, estrogen and progesterone, and are therefore affected by physiological fluctuations of those hormones that occur over the rodent estrous cycle. In this review, we discuss the effects of cycling ovarian hormones on hippocampal physiology. Starting with behavior, we explore the role of the estrous cycle in regulating hippocampus-dependent behaviors. We go on to detail the cellular mechanisms through which cycling estrogen and progesterone, through changes in the structural and functional properties of hippocampal neurons, may be eliciting these changes in behavior. Then, providing a basis for these cellular changes, we outline the epigenetic, chromatin regulatory mechanisms through which ovarian hormones, by binding to their receptors, can affect the regulation of behavior- and synaptic plasticity-related genes in hippocampal neurons. We also highlight an unconventional role that chromatin dynamics may have in regulating neuronal function across the estrous cycle, including in sex hormone-driven X chromosome plasticity and hormonally-induced epigenetic priming. Finally, we discuss directions for future studies and the translational value of the rodent estrous cycle for understanding the effects of the human menstrual cycle on hippocampal physiology and brain disease risk.
Collapse
Affiliation(s)
- Devin Rocks
- Department of Biological Sciences, Fordham University; Bronx, NY, USA
| | - Marija Kundakovic
- Department of Biological Sciences, Fordham University; Bronx, NY, USA
| |
Collapse
|
9
|
Zhang TR, Askari B, Kesici A, Guilherme E, Vila-Rodriguez F, Snyder JS. Intermittent theta burst transcranial magnetic stimulation induces hippocampal mossy fibre plasticity in male but not female mice. Eur J Neurosci 2023; 57:310-323. [PMID: 36484786 DOI: 10.1111/ejn.15891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 11/12/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
Transcranial magnetic stimulation (TMS) induces electric fields that depolarise or hyperpolarise neurons. Intermittent theta burst stimulation (iTBS), a patterned form of TMS that is delivered at the theta frequency (~5 Hz), induces neuroplasticity in the hippocampus, a brain region that is implicated in memory and learning. One form of plasticity that is unique to the hippocampus is adult neurogenesis; however, little is known about whether TMS or iTBS in particular affects newborn neurons. Here, we therefore applied repeated sessions of iTBS to male and female mice and measured the extent of adult neurogenesis and the morphological features of immature neurons. We found that repeated sessions of iTBS did not significantly increase the amount of neurogenesis or affect the gross dendritic morphology of new neurons, and there were no sex differences in neurogenesis rates or aspects of afferent morphology. In contrast, efferent properties of newborn neurons varied as a function of sex and stimulation. Chronic iTBS increased the size of mossy fibre terminals, which synapse onto Cornu Ammonis 3 (CA3) pyramidal neurons, but only in males. iTBS also increased the number of terminal-associated filopodia, putative synapses onto inhibitory interneurons but only in male mice. This efferent plasticity could result from a general trophic effect, or it could reflect accelerated maturation of immature neurons. Given the important role of mossy fibre synapses in hippocampal learning, our results identify a neurobiological effect of iTBS that might be associated with sex-specific changes in cognition.
Collapse
Affiliation(s)
- Tian Rui Zhang
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
- Non-Invasive Neurostimulation Therapies Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Baran Askari
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aydan Kesici
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Evelyn Guilherme
- Department of Physiotherapy, Federal University of Sao Carlos, Sao Carlo, Brazil
| | - Fidel Vila-Rodriguez
- Non-Invasive Neurostimulation Therapies Laboratory, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
10
|
Susceptibility of Female Mice to the Dietary Omega-3/Omega-6 Fatty-Acid Ratio: Effects on Adult Hippocampal Neurogenesis and Glia. Int J Mol Sci 2022; 23:ijms23063399. [PMID: 35328825 PMCID: PMC8950413 DOI: 10.3390/ijms23063399] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 02/04/2023] Open
Abstract
Maternal intake of omega-3 (n-3 PUFAs) and omega-6 (n-6 PUFAs) polyunsaturated fatty acids impacts hippocampal neurogenesis during development, an effect that may extend to adulthood by altering adult hippocampal neurogenesis (AHN). The n-3 PUFAs and n-6 PUFAs are precursors of inflammatory regulators that potentially affect AHN and glia. Additionally, n-3 PUFA dietary supplementation may present a sexually dimorphic action in the brain. Therefore, we postulated that dietary n-6/n-3 PUFA balance shapes the adult DG in a sex-dependent manner influencing AHN and glia. We test our hypothesis by feeding adult female and male mice with n-3 PUFA balanced or deficient diets. To analyze the immunomodulatory potential of the diets, we injected mice with the bacterial endotoxin lipopolysaccharide (LPS). LPS reduced neuroblast number, and its effect was exacerbated by the n-3 PUFA-deficient diet. The n-3 PUFA-deficient diet reduced the DG volume, AHN, microglia number, and surveilled volume. The diet effect on most mature neuroblasts was exclusively significant in female mice. Colocalization and multivariate analysis revealed an association between microglia and AHN, as well as the sexual dimorphic effect of diet. Our study reveals that female mice are more susceptible than males to the effect of dietary n-6/n-3 PUFA ratio on AHN and microglia.
Collapse
|
11
|
Hodges TE, Puri TA, Blankers SA, Qiu W, Galea LAM. Steroid hormones and hippocampal neurogenesis in the adult mammalian brain. VITAMINS AND HORMONES 2021; 118:129-170. [PMID: 35180925 DOI: 10.1016/bs.vh.2021.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hippocampal neurogenesis persists across the lifespan in many species, including rodents and humans, and is associated with cognitive performance and the pathogenesis of neurodegenerative disease and psychiatric disorders. Neurogenesis is modulated by steroid hormones that change across development and differ between the sexes in rodents and humans. Here, we discuss the effects of stress and glucocorticoid exposure from gestation to adulthood as well as the effects of androgens and estrogens in adulthood on neurogenesis in the hippocampus. Throughout the review we highlight sex differences in the effects of steroid hormones on neurogenesis and how they may relate to hippocampal function and disease. These data highlight the importance of examining age and sex when evaluating the effects of steroid hormones on hippocampal neurogenesis.
Collapse
Affiliation(s)
- Travis E Hodges
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Tanvi A Puri
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Samantha A Blankers
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Wansu Qiu
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Department of Psychology, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
| |
Collapse
|
12
|
Wan L, Huang RJ, Luo ZH, Gong JE, Pan A, Manavis J, Yan XX, Xiao B. Reproduction-Associated Hormones and Adult Hippocampal Neurogenesis. Neural Plast 2021; 2021:3651735. [PMID: 34539776 PMCID: PMC8448607 DOI: 10.1155/2021/3651735] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/17/2021] [Indexed: 11/18/2022] Open
Abstract
The levels of reproduction-associated hormones in females, such as estrogen, progesterone, prolactin, and oxytocin, change dramatically during pregnancy and postpartum. Reproduction-associated hormones can affect adult hippocampal neurogenesis (AHN), thereby regulating mothers' behavior after delivery. In this review, we first briefly introduce the overall functional significance of AHN and the methods commonly used to explore this front. Then, we attempt to reconcile the changes of reproduction-associated hormones during pregnancy. We further update the findings on how reproduction-related hormones influence adult hippocampal neurogenesis. This review is aimed at emphasizing a potential role of AHN in reproduction-related brain plasticity and its neurobiological relevance to motherhood behavior.
Collapse
Affiliation(s)
- Lily Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Rou-Jie Huang
- Medical Doctor Program, Xiangya School of Medicine, Central South University, Changsha, China
| | - Zhao-Hui Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jiao-e Gong
- Department of Neurology, Hunan Children's Hospital, Changsha 410007, China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan 410013, China
| | - Jim Manavis
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia 5000
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan 410013, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| |
Collapse
|
13
|
Bartkowska K, Turlejski K, Tepper B, Rychlik L, Vogel P, Djavadian R. Effects of Brain Size on Adult Neurogenesis in Shrews. Int J Mol Sci 2021; 22:7664. [PMID: 34299282 PMCID: PMC8303847 DOI: 10.3390/ijms22147664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 01/02/2023] Open
Abstract
Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size. We examined Crocidura russula and Neomys fodiens, weighing 10-22 g, and Crocidura olivieri and Suncus murinus that weigh three times more. We found that the density of proliferated cells in the SVZ was approximately at the same level in all species. These cells migrated from the SVZ through the rostral migratory stream to the olfactory bulb (OB). In this pathway, a low level of neurogenesis occurred in C. olivieri compared to three other species of shrews. In the DG, the rate of adult neurogenesis was regulated differently. Specifically, the lowest density of newly generated neurons was observed in C. russula, which had a substantial number of new neurons in the OB compared with C. olivieri. We suggest that the number of newly generated neurons in an adult shrew's brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in two neurogenic structures.
Collapse
Affiliation(s)
- Katarzyna Bartkowska
- Nencki Institute of Experimental Biology Polish Academy of Sciences, 02-093 Warsaw, Poland; (K.B.); (B.T.)
| | - Krzysztof Turlejski
- Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszynski University in Warsaw, 01-938 Warsaw, Poland;
| | - Beata Tepper
- Nencki Institute of Experimental Biology Polish Academy of Sciences, 02-093 Warsaw, Poland; (K.B.); (B.T.)
| | - Leszek Rychlik
- Department of Systematic Zoology, Institute of Environmental Biology, Adam Mickiewicz University, 61-712 Poznan, Poland;
| | - Peter Vogel
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland;
| | - Ruzanna Djavadian
- Nencki Institute of Experimental Biology Polish Academy of Sciences, 02-093 Warsaw, Poland; (K.B.); (B.T.)
| |
Collapse
|
14
|
Abotalebi H, Ebrahimi B, Shahriyari R, Shafieian R. Sex steroids-induced neurogenesis in adult brain: a better look at mechanisms and mediators. Horm Mol Biol Clin Investig 2021; 42:209-221. [PMID: 34058796 DOI: 10.1515/hmbci-2020-0036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 01/14/2021] [Indexed: 11/15/2022]
Abstract
Adult neurogenesis is the production of new nerve cells in the adult brain. Neurogenesis is a clear example of the neuroplasticity phenomenon which can be observed in most of mammalian species, including human beings. This phenomenon occurs, at least, in two regions of the brain: the subgranular zone of the dentate gyrus in hippocampus and the ventricular zone of lateral ventricles. Numerous studies have investigated the relationship between sex steroid hormones and neurogenesis of adult brain; of which, mostly concentrated on the role of estradiol. It has been shown that estrogen plays a significant role in this process through both classic and non-classic mechanisms, including a variety of different growth factors. Therefore, the objective of this review is to investigate the role of female sex steroids with an emphasis on estradiol and also its potential implications for regulating the neurogenesis in the adult brain.
Collapse
Affiliation(s)
- Hamideh Abotalebi
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Babak Ebrahimi
- Department of Anatomy and Cell Biology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Raziyeh Shahriyari
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Reyhaneh Shafieian
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| |
Collapse
|
15
|
Trova S, Bovetti S, Pellegrino G, Bonzano S, Giacobini P, Peretto P. HPG-Dependent Peri-Pubertal Regulation of Adult Neurogenesis in Mice. Front Neuroanat 2020; 14:584493. [PMID: 33328903 PMCID: PMC7732626 DOI: 10.3389/fnana.2020.584493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/29/2020] [Indexed: 11/13/2022] Open
Abstract
Adult neurogenesis, a striking form of neural plasticity, is involved in the modulation of social stimuli driving reproduction. Previous studies on adult neurogenesis have shown that this process is significantly modulated around puberty in female mice. Puberty is a critical developmental period triggered by increased secretion of the gonadotropin releasing hormone (GnRH), which controls the activity of the hypothalamic-pituitary-gonadal axis (HPG). Secretion of HPG-axis factors at puberty participates to the refinement of neural circuits that govern reproduction. Here, by exploiting a transgenic GnRH deficient mouse model, that progressively loses GnRH expression during postnatal development (GnRH::Cre;Dicer loxP/loxP mice), we found that a postnatally-acquired dysfunction in the GnRH system affects adult neurogenesis selectively in the subventricular-zone neurogenic niche in a sexually dimorphic way. Moreover, by examining adult females ovariectomized before the onset of puberty, we provide important evidence that, among the HPG-axis secreting factors, the circulating levels of gonadal hormones during pre-/peri-pubertal life contribute to set-up the proper adult subventricular zone-olfactory bulb neurogenic system.
Collapse
Affiliation(s)
- Sara Trova
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy.,Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Giuliana Pellegrino
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Paolo Giacobini
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| |
Collapse
|
16
|
Trammell TS, Henderson NL, Madkour HS, Stanwood GD, Graham DL. GLP-1R activation alters performance in cognitive tasks in a sex-dependent manner. Neurol Sci 2020; 42:2911-2919. [PMID: 33222103 DOI: 10.1007/s10072-020-04910-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/15/2020] [Indexed: 01/22/2023]
Abstract
RATIONALE The activation of the glucagon-like peptide-1 receptor (GLP-1R) has been purported to have antidepressant-like and cognitive-enhancing effects. Many people suffering from major depressive disorder (MDD) also experience deficits in cognition. While currently approved antidepressant pharmacotherapies can alleviate the mood symptoms in some patients, they do not treat the cognitive ones. OBJECTIVES We tested whether systemic administration of a GLP-1R agonist would alter location discrimination, a cognitive task that is diminished in humans with MDD. METHODS Male and female laboratory mice (6-8 weeks old, N = 6-14/sex) were trained in a touchscreen operant task of location discrimination. Upon reaching baseline criterion, mice were administered vehicle or a GLP-1R agonist, Exendin-4, systemically prior to testing in probe trials of varying difficulty. RESULTS Following GLP-1R activation, males showed modest yet non-significant performance in the location discrimination task. Females, however, showed enhanced performance during the most difficult probe tests following Exendin-4 administration. CONCLUSIONS GLP-1R activation appears to enhance overall performance in the location discrimination task and does so in a sex- and difficulty-dependent manner. These preliminary yet impactful data indicate that GLP-1R agonists may be useful as an adjunctive pharmacotherapy to treat cognitive deficits associated with MDD and/or multiple neurological disorders.
Collapse
Affiliation(s)
- Taylor S Trammell
- Department of Biomedical Sciences and Center for Brain Repair, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Natalie L Henderson
- Department of Biomedical Sciences and Center for Brain Repair, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Haley S Madkour
- Department of Biomedical Sciences and Center for Brain Repair, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Gregg D Stanwood
- Department of Biomedical Sciences and Center for Brain Repair, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Devon L Graham
- Department of Biomedical Sciences and Center for Brain Repair, Florida State University College of Medicine, Tallahassee, FL, 32306, USA.
| |
Collapse
|
17
|
Wang H, Matsushita MT, Zhang L, Abel GM, Mommer BC, Huddy TF, Storm DR, Xia Z. Inducible and Conditional Stimulation of Adult Hippocampal Neurogenesis Rescues Cadmium-Induced Impairments of Adult Hippocampal Neurogenesis and Hippocampus-Dependent Memory in Mice. Toxicol Sci 2020; 177:263-280. [PMID: 32617577 PMCID: PMC7553705 DOI: 10.1093/toxsci/kfaa104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cadmium (Cd) is a heavy metal and an environmental pollutant. However, the full spectrum of its neurotoxicity and the underlying mechanisms are not completely understood. Our previous studies demonstrated that Cd exposure impairs adult hippocampal neurogenesis and hippocampus-dependent memory in mice. This study aims to determine if these adverse effects of Cd exposure can be mitigated by genetically and conditionally enhancing adult neurogenesis. To address this issue, we utilized the transgenic constitutive active MEK5 (caMEK5) mouse strain we previously developed and characterized. This mouse strain enables us to genetically and conditionally activate adult neurogenesis by administering tamoxifen to induce expression of a caMEK5 in adult neural stem/progenitor cells, which stimulates adult neurogenesis through activation of the endogenous extracellular signal-regulated kinase 5 mitogen-activated protein kinase pathway. The caMEK5 mice were exposed to 0.6 mg/l Cd through drinking water for 38 weeks. Once impairment of memory was confirmed, tamoxifen was administered to induce caMEK5 expression and to activate adult neurogenesis. Behavior tests were conducted at various time points to monitor hippocampus-dependent memory. Upon completion of the behavior tests, brain tissues were collected for cellular studies of adult hippocampal neurogenesis. We report here that Cd impaired hippocampus-dependent spatial memory and contextual fear memory in mice. These deficits were rescued by the tamoxifen induction of caMEK5 expression. Furthermore, Cd inhibition of adult hippocampal neurogenesis was also reversed. This rescue experiment provides strong evidence for a direct link between Cd-induced impairments of adult hippocampal neurogenesis and hippocampus-dependent memory.
Collapse
Affiliation(s)
- Hao Wang
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| | - Megumi T Matsushita
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| | - Liang Zhang
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| | - Glen M Abel
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| | - Brett C Mommer
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| | | | - Daniel R Storm
- Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Zhengui Xia
- Toxicology Program, Department of Environmental and Occupational Health Sciences
| |
Collapse
|
18
|
Jorgensen C, Wang Z. Hormonal Regulation of Mammalian Adult Neurogenesis: A Multifaceted Mechanism. Biomolecules 2020; 10:biom10081151. [PMID: 32781670 PMCID: PMC7465680 DOI: 10.3390/biom10081151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/27/2020] [Accepted: 08/01/2020] [Indexed: 02/07/2023] Open
Abstract
Adult neurogenesis—resulting in adult-generated functioning, integrated neurons—is still one of the most captivating research areas of neuroplasticity. The addition of new neurons in adulthood follows a seemingly consistent multi-step process. These neurogenic stages include proliferation, differentiation, migration, maturation/survival, and integration of new neurons into the existing neuronal network. Most studies assessing the impact of exogenous (e.g., restraint stress) or endogenous (e.g., neurotrophins) factors on adult neurogenesis have focused on proliferation, survival, and neuronal differentiation. This review will discuss the multifaceted impact of hormones on these various stages of adult neurogenesis. Specifically, we will review the evidence for hormonal facilitation (via gonadal hormones), inhibition (via glucocorticoids), and neuroprotection (via recruitment of other neurochemicals such as neurotrophin and neuromodulators) on newly adult-generated neurons in the mammalian brain.
Collapse
Affiliation(s)
- Claudia Jorgensen
- Behavioral Science Department, Utah Valley University, Orem, UT 84058, USA
- Correspondence:
| | - Zuoxin Wang
- Psychology Department and Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA;
| |
Collapse
|
19
|
Qin Y, An D, Xu W, Qi X, Wang X, Chen L, Chen L, Sha S. Estradiol Replacement at the Critical Period Protects Hippocampal Neural Stem Cells to Improve Cognition in APP/PS1 Mice. Front Aging Neurosci 2020; 12:240. [PMID: 32903757 PMCID: PMC7438824 DOI: 10.3389/fnagi.2020.00240] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022] Open
Abstract
It has been suggested that there is a critical window for estrogen replacement therapy (ERT) in postmenopausal women with Alzheimer’s disease (AD); however, supporting evidence is lacking. To address this issue, we investigated the effective period for estradiol (E2) treatment using a mouse model of AD. Four-month-old female APPswe/PSEN1dE9 (APP/PS1) mice were ovariectomized (OVX) and treated with E2 for 2 months starting at the age of 4 months (early period), 6 months (mid-period), or 8 months (late period). We then evaluated hippocampal neurogenesis, β-amyloid (Aβ) accumulation, telomerase activity, and hippocampal-dependent behavior. Compared to age-matched wild type mice, APP/PS1 mice with intact ovaries showed increased proliferation of hippocampal neural stem cells (NSCs) at 8 months of age and decreased proliferation of NSCs at 10 months of age; meanwhile, Aβ accumulation progressively increased with age, paralleling the reduced survival of immature neurons. OVX-induced depletion of E2 in APP/PS1 mice resulted in elevated Aβ levels accompanied by elevated p75 neurotrophin receptor (p75NTR) expression and increased NSC proliferation at 6 months of age, which subsequently declined; accelerated reduction of immature neurons starting from 6 months of age, and reduced telomerase activity and worsened memory performance at 10 months of age. Treatment with E2 in the early period post-OVX, rather than in the mid or late period, abrogated these effects, and p75NTR inhibition reduced the overproliferation of NSCs in 6-month-old OVX-APP/PS1 mice. Thus, E2 deficiency in young APP/PS1 mice exacerbates cognitive deficits and depletes the hippocampal NSC pool in later life; this can be alleviated by E2 treatment in the early period following OVX, which prevents Aβ/p75NTR-induced NSC overproliferation and preserves telomerase activity.
Collapse
Affiliation(s)
- Yaoyao Qin
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Dong An
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Weixing Xu
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiuting Qi
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiaoli Wang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Ling Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China.,State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Sha Sha
- Department of Physiology, Nanjing Medical University, Nanjing, China.,State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| |
Collapse
|
20
|
Sex Differences in Maturation and Attrition of Adult Neurogenesis in the Hippocampus. eNeuro 2020; 7:ENEURO.0468-19.2020. [PMID: 32586842 PMCID: PMC7369314 DOI: 10.1523/eneuro.0468-19.2020] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022] Open
Abstract
Sex 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 2 h, 24 h, one week (1w), 2w, or 3w after bromodeoxyuridine (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 with 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 1week and 2weeks after mitosis, whereas females showed similar levels of neurogenesis throughout the weeks. The faster maturation and greater attrition of new neurons in males compared with females suggests greater potential for neurogenesis to respond to external stimuli in males and emphasizes the importance of studying sex on adult hippocampal neurogenesis.
Collapse
|
21
|
Fluoxetine effects on behavior and adult hippocampal neurogenesis in female C57BL/6J mice across the estrous cycle. Psychopharmacology (Berl) 2020; 237:1281-1290. [PMID: 31965254 PMCID: PMC7196514 DOI: 10.1007/s00213-020-05456-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/10/2020] [Indexed: 12/11/2022]
Abstract
RATIONALE Some mood disorders, such as major depressive disorder, are more prevalent in women than in men. However, historically preclinical studies in rodents have a lower inclusion rate of females than males, possibly due to the fact that behavior can be affected by the estrous cycle. Several studies have demonstrated that chronic antidepressant treatment can decrease anxiety-associated behaviors and increase adult hippocampal neurogenesis in male rodents. OBJECTIVE Very few studies have looked at the effects of antidepressants on behavior and neurogenesis across the estrous cycle in naturally cycling female rodents. METHODS Here, we analyze the effects of chronic treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine (Prozac) on behavior and adult hippocampal neurogenesis in naturally cycling C57BL/6J females across all four phases of the estrous cycle. RESULTS In naturally cycling C57BL/6J females, fluoxetine decreases negative valence behaviors associated with anxiety in the elevated plus maze and novelty-suppressed feeding task, reduces immobility time in forced swim test, and increases adult hippocampal neurogenesis. Interestingly, the effects of fluoxetine on several negative valence behavior and adult hippocampal neurogenesis measures were mainly found within the estrus and diestrus phases of the estrous cycle. CONCLUSIONS Taken together, these data are the first to illustrate the effects of fluoxetine on behavior and adult hippocampal neurogenesis across all four phases of the murine estrous cycle.
Collapse
|
22
|
Connolly MG, Yost OL, Potter OV, Giedraitis ME, Kohman RA. Toll-like receptor 4 differentially regulates adult hippocampal neurogenesis in an age- and sex-dependent manner. Hippocampus 2020; 30:958-969. [PMID: 32343455 DOI: 10.1002/hipo.23209] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 12/15/2022]
Abstract
Toll-like receptor 4 (TLR4) is primarily responsible for initiating an immune response following pathogen recognition. However, TLR4 is also expressed on neural progenitor cells and has been reported to regulate hippocampal neurogenesis as young male TLR4 knockout mice show increases in cell proliferation and doublecortin positive cells. Whether these effects occur in both sexes and are sustained with normal aging is currently unknown. The present study evaluated whether TLR4 deficiency alters adult hippocampal neurogenesis in young (3-4 months) and aged (18-20 months), male and female, TLR4 deficient (TLR4-/-; B6.B10ScN-Tlr4lps-del/JthJ) and wild type (WT) mice. Additionally, neurogenesis within the dorsal and the ventral hippocampal subdivisions was evaluated to determine if TLR4 has differential effects across the hippocampus. Bromodeoxyuridine (BrdU) was administered to quantify new cell survival as well as cell differentiation. Ki-67 was measured to evaluate cell proliferation. Results show that young TLR4-/- females had higher rates of proliferation and neuronal differentiation in both the dorsal and ventral hippocampus relative to WT females. Young TLR4-/- males show elevated proliferation and neuronal differentiation mainly in the ventral hippocampus. While young TLR4-/- mice show enhanced neurogenesis compared to young WT mice, the increase was not apparent in the aged TLR4-/- mice. Both aged WT and TLR4-/- mice showed a decrease in proliferation, new cell survival, and neuronal differentiation compared to young WT and TLR4-/- mice. The data collectively indicate that TLR4 regulates hippocampal neurogenesis in young adults, but that these effects are region-specific in males and that females show broader changes in neurogenesis throughout the hippocampus.
Collapse
Affiliation(s)
- Meghan G Connolly
- Department of Psychology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Oriana L Yost
- Department of Psychology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Opal V Potter
- School of Medicine, Wake Forest University, Winston Salem, North Carolina, USA
| | - Megan E Giedraitis
- Department of Psychology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Rachel A Kohman
- Department of Psychology, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| |
Collapse
|
23
|
Spritzer MD, Roy EA. Testosterone and Adult Neurogenesis. Biomolecules 2020; 10:biom10020225. [PMID: 32028656 PMCID: PMC7072323 DOI: 10.3390/biom10020225] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/22/2020] [Accepted: 01/28/2020] [Indexed: 12/16/2022] Open
Abstract
It is now well established that neurogenesis occurs throughout adulthood in select brain regions, but the functional significance of adult neurogenesis remains unclear. There is considerable evidence that steroid hormones modulate various stages of adult neurogenesis, and this review provides a focused summary of the effects of testosterone on adult neurogenesis. Initial evidence came from field studies with birds and wild rodent populations. Subsequent experiments with laboratory rodents have tested the effects of testosterone and its steroid metabolites upon adult neurogenesis, as well as the functional consequences of induced changes in neurogenesis. These experiments have provided clear evidence that testosterone increases adult neurogenesis within the dentate gyrus region of the hippocampus through an androgen-dependent pathway. Most evidence indicates that androgens selectively enhance the survival of newly generated neurons, while having little effect on cell proliferation. Whether this is a result of androgens acting directly on receptors of new neurons remains unclear, and indirect routes involving brain-derived neurotrophic factor (BDNF) and glucocorticoids may be involved. In vitro experiments suggest that testosterone has broad-ranging neuroprotective effects, which will be briefly reviewed. A better understanding of the effects of testosterone upon adult neurogenesis could shed light on neurological diseases that show sex differences.
Collapse
Affiliation(s)
- Mark D. Spritzer
- Department of Biology, Middlebury College, Middlebury, VT 05753, USA
- Correspondence: ; Tel.: 802-443-5676
| | - Ethan A. Roy
- Graduate School of Education, Stanford University, Stanford, CA 94305, USA;
| |
Collapse
|
24
|
Prolactin, Estradiol and Testosterone Differentially Impact Human Hippocampal Neurogenesis in an In Vitro Model. Neuroscience 2020; 454:15-39. [PMID: 31930958 PMCID: PMC7839971 DOI: 10.1016/j.neuroscience.2019.12.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 12/20/2022]
Abstract
Human hippocampal progenitor cells (HPCs) and tissue express classical sex hormone receptors. Prolactin does not impact human HPCs maintained in a proliferative state. Prolactin increases neuronal differentiation of human HPCs only in the short term. Estradiol and testosterone both increase the cell density of proliferating HPCs. Estradiol and testosterone have no observed effect on differentiating HPCs.
Previous studies have indicated that sex hormones such as prolactin, estradiol and testosterone may play a role in the modulation of adult hippocampal neurogenesis (AHN) in rodents and non-human primates, but so far there has been no investigation of their impact on human hippocampal neurogenesis. Here, we quantify the expression levels of the relevant receptors in human post-mortem hippocampal tissue and a human hippocampal progenitor cell (HPC) line. Secondly, we investigate how these hormones modulate hippocampal neurogenesis using a human in vitro cellular model. Human female HPCs were cultured with biologically relevant concentrations of either prolactin, estradiol or testosterone. Bromodeoxyuridine (BrdU) incorporation, immunocytochemistry (ICC) and high-throughput analyses were used to quantify markers determining cell fate after HPCs were either maintained in a proliferative state or allowed to differentiate in the presence of these hormones. In proliferating cells, estrogen and testosterone increased cell density but had no clear effect on markers of proliferation or cell death to account for this. In differentiating cells, a 3-day treatment of prolactin elicited a transient effect, whereby it increased the proportion of microtubule-associated protein 2 (MAP2)-positive and Doublecortin (DCX)-positive cells, but this effect was not apparent after 7-days. At this timepoint we instead observe a decrease in proliferation. Overall, our study demonstrates relatively minor, and possibly short-term effects of sex hormones on hippocampal neurogenesis in human cells. Further work will be needed to understand if our results differ to previous animal research due to species-specific differences, or whether it relates to limitations of our in vitro model.
Collapse
|
25
|
Johnson A, Rainville JR, Rivero-Ballon GN, Dhimitri K, Hodes GE. Testing the Limits of Sex Differences Using Variable Stress. Neuroscience 2020; 454:72-84. [PMID: 31917340 DOI: 10.1016/j.neuroscience.2019.12.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 02/07/2023]
Abstract
Depression is a chronic disease that affects nearly twice as many women as men, and symptoms can differ by sex. Preclinical models disproportionately use male subjects and test a single behavioral endpoint immediately at the cessation of stress. We conducted variable stress in male and female mice for 6, 28, and 56 days, and measured behavior with a battery chosen to match research domain criteria. To examine individual differences, we generated a composite z score to measure stress susceptibility across behavioral tests. We also tested behavior following a 30-day recovery period to evaluate the duration of the stress effects. Females, but not males, were susceptible to 6 days of variable stress when behavioral testing started 24 h later. If behavioral testing was conducted 30 days later both males and females expressed stress related behaviors. Males and females were stress susceptible to 28 days of variable stress and effects were long lasting. Both sexes habituated to 56 days of variable stress, but anxiety associated measures still showed persistence. Performance on specific behavioral tests was often different between individuals and between sexes, and not all stressed animals were susceptible to all tested behaviors. These studies confirm that behavioral sex differences are detected in response to variable stress, and reveal information about individual differences. Use of a test battery that measures varying endophenotypes can be combined into a single stress susceptibility score as a tool similar to the scales/inventories used for the study of depression in humans. We present these data with the goal of furthering the field's understanding sex differences and how they shape the biology of mood disorders.
Collapse
Affiliation(s)
- Alyssa Johnson
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Jennifer R Rainville
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - G Nicole Rivero-Ballon
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Katerina Dhimitri
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Georgia E Hodes
- School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
| |
Collapse
|
26
|
High-Fat Diet-Induced Obesity Causes Sex-Specific Deficits in Adult Hippocampal Neurogenesis in Mice. eNeuro 2020; 7:ENEURO.0391-19.2019. [PMID: 31871124 PMCID: PMC6946541 DOI: 10.1523/eneuro.0391-19.2019] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/26/2019] [Accepted: 12/01/2019] [Indexed: 12/13/2022] Open
Abstract
Adult hippocampal neurogenesis (AHN) is suppressed by high-fat (HF) diet and metabolic disease, including obesity and type 2 diabetes. Deficits in AHN may contribute to cognitive decline and increased risk of dementia and mood disorders, which have higher prevalence in women. However, sex differences in the effects of HF diet/metabolic disease on AHN have yet to be thoroughly investigated. Herein, male and female C57BL/6J mice were fed an HF or control (CON) diet from ∼2 to 6 months of age. After 3 months on the diet, mice were injected with 5-ethynyl-2′-deoxyuridine (EdU) then killed 4 weeks later. Cell proliferation, differentiation/maturation, and survival of new neurons in the dentate gyrus were assessed with immunofluorescence for EdU, Ki67, doublecortin (DCX), and NeuN. CON females had more proliferating cells (Ki67+) and neuroblasts/immature neurons (DCX+) compared with CON males; however, HF diet reduced these cells in females to the levels of males. Diet did not affect neurogenesis in males. Further, the numbers of proliferating cells and immature neurons were inversely correlated with both weight gain and glucose intolerance in females only. These effects were robust in the dorsal hippocampus, which supports cognitive processes. Assessment of microglia in the dentate gyrus using immunofluorescence for Iba1 and CD68 uncovered sex-specific effects of diet, which may contribute to observed differences in neurogenesis. These findings demonstrate sex-specific effects of HF diet/metabolic disease on AHN, and highlight the potential for targeting neurogenic deficits to treat cognitive decline and reduce the risk of dementia associated with these conditions, particularly in females.
Collapse
|
27
|
Hillerer KM, Slattery DA, Pletzer B. Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus. Front Neuroendocrinol 2019; 55:100796. [PMID: 31580837 PMCID: PMC7115954 DOI: 10.1016/j.yfrne.2019.100796] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/19/2022]
Abstract
Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.
Collapse
Affiliation(s)
- Katharina M Hillerer
- Department of Obstetrics and Gynaecology, Salzburger Landeskrankenhaus (SALK), Paracelsus Medical University (PMU), Clinical Research Center Salzburg (CRCS), Salzburg, Austria.
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital, Goethe University, Frankfurt, Germany
| | - Belinda Pletzer
- Department of Psychology, University of Salzburg, Salzburg, Austria; Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| |
Collapse
|
28
|
Constitutive PGC-1α overexpression in skeletal muscle does not protect from age-dependent decline in neurogenesis. Sci Rep 2019; 9:12320. [PMID: 31444397 PMCID: PMC6707251 DOI: 10.1038/s41598-019-48795-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/29/2019] [Indexed: 01/26/2023] Open
Abstract
Aerobic exercise prevents age-dependent decline in cognition and hippocampal neurogenesis. The transcription factor peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1α) mediates many of the exercise-induced benefits in skeletal muscle, including the release of factors into the circulation with neurotrophic effects. We use a transgenic mouse model with muscle-specific overexpression of PGC-1α to study the contribution of chronic muscle activation on exercise-induced effects on hippocampal neurogenesis in aging. Young and old transgenic and wild type animals of both sexes displayed a robust age-related reduction in newborn BrdU+-cells, immature neurons (DCX+-cells) and new mature BrdU+/NeuN+-neurons in the dentate gyrus. No differences were detected between genotypes or sexes. Analysis of serum proteins showed a tendency towards increased levels of myokines and reduced levels of pro-inflammatory cytokines for transgenic animals, but only musclin was found to be significantly up-regulated in transgenic animals. We conclude that constitutive muscular overexpression of PGC-1α, despite potent systemic changes, is insufficient for mimicking exercise-induced effects on hippocampal neurogenesis in aging. Continued studies are required to investigate the complex molecular mechanisms by which circulating signals could mediate exercise-induced effects on the central nervous system in disease and aging, with the aim of discovering new therapeutic possibilities for patients.
Collapse
|
29
|
Sex-specific neurogenic deficits and neurocognitive disorders in middle-aged HIV-1 Tg26 transgenic mice. Brain Behav Immun 2019; 80:488-499. [PMID: 30999016 PMCID: PMC6660421 DOI: 10.1016/j.bbi.2019.04.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 04/11/2019] [Accepted: 04/15/2019] [Indexed: 11/23/2022] Open
Abstract
Varying degrees of cognitive deficits affect over half of all HIV-1 infected patients. Because of antiretroviral treatment (ART) regimens, the HIV-1 patient population is increasing in age. Very few epidemiological studies have focused on sex-specific differences in HIV-1-associated neurocognitive disorders (HAND). The purpose of this study is to examine any possible differences between male and female mice in the progression of cognitive dementia during persistent low-level HIV-1 protein exposure, mimicking the typical clinical setting in the post-ART era. Eight to ten-month old HIV-1 Tg26(+/-) transgenic mice were utilized to assess for specific learning and memory modalities. Initial physiological screening and fear conditioning assessments revealed that Tg26 mice exhibited no significant differences in general behavioral function, contextual fear conditioning, or cued fear conditioning responses when compared to their wild-type (WT) littermates, regardless of sex. However, Barnes maze testing revealed significantly impaired short and long-term spatial memory in males, while females had impaired spatial learning abilities and short-term spatial memory. The potential cellular mechanism underlying these sex-specific neurocognitive deficits was explored with hippocampal neurogenic analysis. Compared to WT mice, both male and female Tg26(+/-) mice had fewer quiescent neural stem cells and neuroblasts in their hippocampi. Male Tg26(+/-) mice had a more robust reduction of the quiescent neural stem cell pool than female Tg26(+/-) mice. While female WT mice had a higher number of neural progenitor cells than male WT mice, only female Tg26(+/-) mice exhibited a robust reduction in the number of neural progenitor cells. Altogether, these results suggest that middle-aged male and female Tg26(+/-) mice manifest differing impairments in cognitive functioning and hippocampal neurogenesis. This study emphasizes the importance of understanding sex related differences in HAND pathology, which would aid in designing more optimized therapeutic regimens for the treatment of HAND.
Collapse
|
30
|
Snitow ME, Zanni G, Ciesielski B, Burgess-Jones P, Eisch AJ, O'Brien WT, Klein PS. Adult hippocampal neurogenesis is not necessary for the response to lithium in the forced swim test. Neurosci Lett 2019; 704:67-72. [PMID: 30940476 PMCID: PMC6594907 DOI: 10.1016/j.neulet.2019.03.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 11/22/2022]
Abstract
Chronic lithium treatment stimulates adult hippocampal neurogenesis, but whether increased neurogenesis contributes to its therapeutic mechanism remains unclear. We use a genetic model of neural progenitor cell (NPC) ablation to test whether a lithium-sensitive behavior requires hippocampal neurogenesis. NPC-ablated mice were treated with lithium and assessed in the forced swim test (FST). Lithium reduced time immobile in the FST in NPC-ablated and control mice but had no effect on activity in the open field, a control for the locomotion-based FST. These findings show that hippocampal NPCs that proliferate in response to chronic lithium are not necessary for the behavioral response to lithium in the FST. We further show that 4-6 week old immature hippocampal neurons are not required for this response. These data suggest that increased hippocampal neurogenesis does not contribute to the response to lithium in the forced swim test and may not be an essential component of its therapeutic mechanism.
Collapse
Affiliation(s)
- Melinda E Snitow
- Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Giulia Zanni
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Brianna Ciesielski
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Pamela Burgess-Jones
- Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Amelia J Eisch
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Neuroscience, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - W Timothy O'Brien
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
| | - Peter S Klein
- Department of Medicine, Division of Hematology-Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
| |
Collapse
|
31
|
Sex steroid hormone modulation of neural stem cells: a critical review. Biol Sex Differ 2019; 10:28. [PMID: 31146782 PMCID: PMC6543604 DOI: 10.1186/s13293-019-0242-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/13/2019] [Indexed: 12/18/2022] Open
Abstract
While numerous in vivo experiments have sought to explore the effects of sex chromosome composition and sex steroid hormones on cellular proliferation and differentiation within the mammalian brain, far fewer studies as reviewed here, have explored these factors using a direct in vitro approach. Generally speaking, in vivo studies provide the gold standard to demonstrate applicable findings in regards to the role hormones play in development. However, in the case of neural stem cell (NSC) biology, there remain many unknown factors that likely contribute to observations made within the developed brain, specifically in regions where there are abundant sex steroid hormone receptors. For these reasons, using a NSC in vitro model may provide a more controlled and refined system to explore the direct effects of sex and hormone response, limiting the vast array of other influences on NSCs occurring during development and within adult cellular niches. These specific cellular models may have the ability to greatly improve the mechanistic understanding of changes occurring within the developing brain during the hormonal organization process, in addition to other modifications that may contribute to neuro-psychiatric sex-biased diseases.
Collapse
|
32
|
Kolmogorova D, Paré C, Kostuck S, Hudson EC, Lebel N, Houlding E, Gregory JG, Ismail N. Pubertal immune stress transiently alters spatial memory processes in adulthood. Psychoneuroendocrinology 2019; 102:261-272. [PMID: 30594819 DOI: 10.1016/j.psyneuen.2018.12.224] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/20/2018] [Accepted: 12/17/2018] [Indexed: 02/08/2023]
Abstract
Pubertal immune challenge can permanently alter hippocampus-dependent memory processes in a sex-specific manner. Although gonadal hormones can influence various cognitive processes, their role in regulating the cognitive sequelae to pubertal immune challenge has not been thoroughly assessed. We examined whether a pubertal immune challenge could affect hippocampus-dependent memory functions in adulthood and whether these effects are regulated by gonadal steroid hormones. We hypothesized that exposure to an immune challenge during puberty would induce sex-specific deficits in the behavioral and cellular correlates of hippocampus-dependent memory during adulthood. At six weeks of age, during the stress-vulnerable pubertal period, male and female CD-1 mice were injected with either saline or the bacterial endotoxin lipopolysaccharide (LPS). Three weeks later, mice underwent either gonadectomy or sham-surgery. At ten weeks of age (i.e., in adulthood), mice began behavioral testing in an open field, Barnes maze, and Morris water maze. Brain tissue was collected at 17 weeks of age and stained for doublecortin and Ki67 to examine migrating neuronal progenitor cells and cellular proliferation in the neurogenic subgranular zone (SGZ) and the cornus ammonis (CA)1 and CA3 regions of the hippocampus. Pubertal LPS treatment impaired learning during adulthood in both sexes and increased cellular proliferation in the CA1 region in castrated males only. Although adult sex hormones did not reliably modulate these changes, gonadectomy impaired learning during the Morris water maze in both sexes. Learning deficits were more prominent during the Barnes maze, which suggests a stress-dependent expression of LPS-induced cognitive deficits. Neurogenesis in the SGZ and cellular proliferation in the CA3 were not affected by pubertal LPS treatment or gonadectomy. These novel findings emphasize the sensitivity of developing cognitive processes during puberty to immune challenges and suggest a possible mechanism for learning-based difficulties in adulthood.
Collapse
Affiliation(s)
- Daria Kolmogorova
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Catherine Paré
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Sarah Kostuck
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Ella Christine Hudson
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada; School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Nicholas Lebel
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Elizabeth Houlding
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - James Gardner Gregory
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada; Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Nafissa Ismail
- NISE Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
| |
Collapse
|
33
|
FGF-23 Deficiency Impairs Hippocampal-Dependent Cognitive Function. eNeuro 2019; 6:eN-NRS-0469-18. [PMID: 30911673 PMCID: PMC6430630 DOI: 10.1523/eneuro.0469-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 01/05/2023] Open
Abstract
Fibroblast growth factor receptor (FGFR) and α-Klotho transduce FGF-23 signaling in renal tubules to maintain systemic phosphate/vitamin D homeostasis. Mice deficient for either the ligand, FGF-23, or the co-receptor, Klotho, are phenocopies with both showing rapid and premature development of multiple aging-like abnormalities. Such similarity in phenotype, suggests that FGF-23 and Klotho have co-dependent systemic functions. Recent reports revealed inverse central nervous system (CNS) effects of Klotho deficiency or Klotho overexpression on hippocampal synaptic, neurogenic, and cognitive functions. However, it is unknown whether FGF-23 deficiency effects function of the hippocampus. We report that, similar to Klotho-deficient mice, FGF-23-deficient mice develop dose-dependent, hippocampal-dependent cognitive impairment. However, FGF-23-deficient brains had no gross structural or developmental defects, no change in hippocampal synaptic plasticity, and only minor impairment to postnatal hippocampal neurogenesis. Together, these data provide evidence that FGF-23 deficiency impairs hippocampal-dependent cognition but otherwise results in a brain phenotype that is distinct from the KL-deficient mouse.
Collapse
|
34
|
Sheppard PAS, Choleris E, Galea LAM. Structural plasticity of the hippocampus in response to estrogens in female rodents. Mol Brain 2019; 12:22. [PMID: 30885239 PMCID: PMC6423800 DOI: 10.1186/s13041-019-0442-7] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/11/2019] [Indexed: 01/05/2023] Open
Abstract
It is well established that estrogens affect neuroplasticity in a number of brain regions. In particular, estrogens modulate and mediate spine and synapse formation as well as neurogenesis in the hippocampal formation. In this review, we discuss current research exploring the effects of estrogens on dendritic spine plasticity and neurogenesis with a focus on the modulating factors of sex, age, and pregnancy. Hormone levels, including those of estrogens, fluctuate widely across the lifespan from early life to puberty, through adulthood and into old age, as well as with pregnancy and parturition. Dendritic spine formation and modulation are altered both by rapid (likely non-genomic) and classical (genomic) actions of estrogens and have been suggested to play a role in the effects of estrogens on learning and memory. Neurogenesis in the hippocampus is influenced by age, the estrous cycle, pregnancy, and parity in female rodents. Furthermore, sex differences exist in hippocampal cellular and molecular responses to estrogens and are briefly discussed throughout. Understanding how structural plasticity in the hippocampus is affected by estrogens and how these effects can influence function and be influenced by other factors, such as experience and sex, is critical and can inform future treatments in conditions involving the hippocampus.
Collapse
Affiliation(s)
- Paul A. S. Sheppard
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - Elena Choleris
- Department of Psychology & Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1 Canada
| | - Liisa A. M. Galea
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| |
Collapse
|
35
|
Yagi S, Galea LAM. Sex differences in hippocampal cognition and neurogenesis. Neuropsychopharmacology 2019; 44:200-213. [PMID: 30214058 PMCID: PMC6235970 DOI: 10.1038/s41386-018-0208-4] [Citation(s) in RCA: 193] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 12/27/2022]
Abstract
Sex differences are reported in hippocampal plasticity, cognition, and in a number of disorders that target the integrity of the hippocampus. For example, meta-analyses reveal that males outperform females on hippocampus-dependent tasks in rodents and in humans, furthermore women are more likely to experience greater cognitive decline in Alzheimer's disease and depression, both diseases characterized by hippocampal dysfunction. The hippocampus is a highly plastic structure, important for processing higher order information and is sensitive to the environmental factors such as stress. The structure retains the ability to produce new neurons and this process plays an important role in pattern separation, proactive interference, and cognitive flexibility. Intriguingly, there are prominent sex differences in the level of neurogenesis and the activation of new neurons in response to hippocampus-dependent cognitive tasks in rodents. However, sex differences in spatial performance can be nuanced as animal studies have demonstrated that there are task, and strategy choice dependent sex differences in performance, as well as sex differences in the subregions of the hippocampus influenced by learning. This review discusses sex differences in pattern separation, pattern completion, spatial learning, and links between adult neurogenesis and these cognitive functions of the hippocampus. We emphasize the importance of including both sexes when studying genomic, cellular, and structural mechanisms of the hippocampal function.
Collapse
Affiliation(s)
- Shunya Yagi
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Liisa A M Galea
- Department of Psychology, Graduate Program in Neuroscience, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
| |
Collapse
|
36
|
Dey SK, Kamle A, Dereddi RR, Thomas SM, Thummala SR, Kumar A, Chakravarty S, Jesudasan RA. Mice With Partial Deletion of Y-Heterochromatin Exhibits Stress Vulnerability. Front Behav Neurosci 2018; 12:215. [PMID: 30297990 PMCID: PMC6160548 DOI: 10.3389/fnbeh.2018.00215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/27/2018] [Indexed: 12/15/2022] Open
Abstract
The role of Y chromosome in sex determination and male fertility is well established. It is also known that infertile men are prone to psychological disturbances. Earlier studies in the laboratory identified genes expressed in testes that are putatively regulated by Y chromosome in man and mouse. With the availability of a Y-deleted mouse model, that is subfertile, we studied the effect of a partial deletion of Y-chromosomal heterochromatin on mouse behavior when compared to its wild type. The partial Y-deleted mice exhibited anxiety like phenotype under stress when different anxiety (open field test and elevated plus maze, EPM test) and depression related tests (tail suspension and force swim) were performed. The mutant mice also showed reduction in hippocampal neurogenesis and altered expression of neurogenesis markers such as Nestin, Sox2, Gfap, NeuroD1 and Dcx using quantitative real time PCR (qPCR) analysis. The genes with altered expression contained short stretches of homology to Y-derived transcripts only in their Untranslated Regions (UTRs). Our study suggests putative regulation of these genes by the Y chromosome in mouse brain altering stress related behavior.
Collapse
Affiliation(s)
- Sandeep Kumar Dey
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
- CSIR-Indian Institute of Chemical Technology, Hyderabad, India
| | - Avijeet Kamle
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Shiju M. Thomas
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Arvind Kumar
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | |
Collapse
|
37
|
Hain EG, Sparenberg M, Rasińska J, Klein C, Akyüz L, Steiner B. Indomethacin promotes survival of new neurons in the adult murine hippocampus accompanied by anti-inflammatory effects following MPTP-induced dopamine depletion. J Neuroinflammation 2018; 15:162. [PMID: 29803225 PMCID: PMC5970532 DOI: 10.1186/s12974-018-1179-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 04/25/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Parkinson's disease (PD) is characterized by dopaminergic cell loss and inflammation in the substantia nigra (SN) leading to motor deficits but also to hippocampus-associated non-motor symptoms such as spatial learning and memory deficits. The cognitive decline is correlated with impaired adult hippocampal neurogenesis resulting from dopamine deficit and inflammation, represented in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) mouse model of PD. In the inflammatory tissue, cyclooxygenase (COX) is upregulated leading to an ongoing inflammatory process such as prostaglandin-mediated increased cytokine levels. Therefore, inhibition of COX by indomethacin may prevent the inflammatory response and the impairment of adult hippocampal neurogenesis. METHODS Wildtype C57Bl/6 and transgenic Nestin-GFP mice were treated with MPTP followed by short-term or long-term indomethacin treatment. Then, aspects of inflammation and neurogenesis were evaluated by cell counts using immunofluorescence and immunohistochemical stainings in the SN and dentate gyrus (DG). Furthermore, hippocampal mRNA expression of neurogenesis-related genes of the Notch, Wnt, and sonic hedgehog signaling pathways and neurogenic factors were assessed, and protein levels of serum cytokines were measured. RESULTS Indomethacin restored the reduction of the survival rate of new mature neurons and reduced the amount of amoeboid CD68+ cells in the DG after MPTP treatment. Indomethacin downregulated genes of the Wnt and Notch signaling pathways and increased neuroD6 expression. In the SN, indomethacin reduced the pro-inflammatory cellular response without reversing dopaminergic cell loss. CONCLUSION Indomethacin has a pro-neurogenic and thereby restorative effect and an anti-inflammatory effect on the cellular level in the DG following MPTP treatment. Therefore, COX inhibitors such as indomethacin may represent a therapeutic option to restore adult neurogenesis in PD.
Collapse
Affiliation(s)
- Elisabeth G Hain
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany.
| | - Maria Sparenberg
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
| | - Justyna Rasińska
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
| | - Charlotte Klein
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
| | - Levent Akyüz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin, and Berlin Institute of Health, Institute for Medical Immunology, Augustenburger Platz 1, 13353, Berlin, Germany.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin, and Berlin Institute of Health, Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Augustenburger Platz 1, 13353, Berlin, Germany
| | - Barbara Steiner
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
| |
Collapse
|
38
|
Gheorghe A, Qiu W, Galea LAM. Hormonal Regulation of Hippocampal Neurogenesis: Implications for Depression and Exercise. Curr Top Behav Neurosci 2018; 43:379-421. [PMID: 30414016 DOI: 10.1007/7854_2018_62] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Adult hippocampal neurogenesis exists in all mammalian species, including humans, and although there has been considerable research investigating the function and regulation of neurogenesis, there remain many open questions surrounding the complexity of this phenomenon. This stems partially from the fact that neurogenesis is a multistage process that involves proliferation, differentiation, migration, survival, and eventual integration of new cells into the existing hippocampal circuitry, each of which can be independently influenced. The function of adult neurogenesis in the hippocampus is related to stress regulation, behavioral efficacy of antidepressants, long-term spatial memory, forgetting, and pattern separation. Steroid hormones influence the regulation of hippocampal neurogenesis, stress regulation, and cognition and differently in males and females. In this chapter, we will briefly tap into the complex network of steroid hormone modulation of neurogenesis in the hippocampus with specific emphasis on stress, testosterone, and estrogen. We examine the possible role of neurogenesis in the etiology of depression and influencing treatment by examining the influence of both pharmacological (selective serotonin reuptake inhibitors, tricyclic antidepressants) treatments and non-pharmacological (exercise) remedies.
Collapse
Affiliation(s)
- Ana Gheorghe
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Wansu Qiu
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Liisa A M Galea
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada. .,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada. .,Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
| |
Collapse
|
39
|
O'Léime CS, Cryan JF, Nolan YM. Nuclear deterrents: Intrinsic regulators of IL-1β-induced effects on hippocampal neurogenesis. Brain Behav Immun 2017; 66:394-412. [PMID: 28751020 DOI: 10.1016/j.bbi.2017.07.153] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/15/2017] [Accepted: 07/23/2017] [Indexed: 12/11/2022] Open
Abstract
Hippocampal neurogenesis, the process by which new neurons are born and develop into the host circuitry, begins during embryonic development and persists throughout adulthood. Over the last decade considerable insights have been made into the role of hippocampal neurogenesis in cognitive function and the cellular mechanisms behind this process. Additionally, an increasing amount of evidence exists on the impact of environmental factors, such as stress and neuroinflammation on hippocampal neurogenesis and subsequent impairments in cognition. Elevated expression of the pro-inflammatory cytokine interleukin-1β (IL-1β) in the hippocampus is established as a significant contributor to the neuronal demise evident in many neurological and psychiatric disorders and is now known to negatively regulate hippocampal neurogenesis. In order to prevent the deleterious effects of IL-1β on neurogenesis it is necessary to identify signalling pathways and regulators of neurogenesis within neural progenitor cells that can interact with IL-1β. Nuclear receptors are ligand regulated transcription factors that are involved in modulating a large number of cellular processes including neurogenesis. In this review we focus on the signalling mechanisms of specific nuclear receptors involved in regulating neurogenesis (glucocorticoid receptors, peroxisome proliferator activated receptors, estrogen receptors, and nuclear receptor subfamily 2 group E member 1 (NR2E1 or TLX)). We propose that these nuclear receptors could be targeted to inhibit neuroinflammatory signalling pathways associated with IL-1β. We discuss their potential to be therapeutic targets for neuroinflammatory disorders affecting hippocampal neurogenesis and associated cognitive function.
Collapse
Affiliation(s)
- Ciarán S O'Léime
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Institute, University College Cork, Ireland
| | - Yvonne M Nolan
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Institute, University College Cork, Ireland.
| |
Collapse
|
40
|
Laszczyk AM, Fox-Quick S, Vo HT, Nettles D, Pugh PC, Overstreet-Wadiche L, King GD. Klotho regulates postnatal neurogenesis and protects against age-related spatial memory loss. Neurobiol Aging 2017; 59:41-54. [PMID: 28837861 PMCID: PMC5612914 DOI: 10.1016/j.neurobiolaging.2017.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/22/2017] [Accepted: 07/21/2017] [Indexed: 12/29/2022]
Abstract
Although the absence of the age-regulating klotho protein causes klotho-deficient mice to rapidly develop cognitive impairment and increasing klotho enhances hippocampal-dependent memory, the cellular effects of klotho that mediate hippocampal-dependent memory function are unknown. Here, we show premature aging of the klotho-deficient hippocampal neurogenic niche as evidenced by reduced numbers of neural stem cells, decreased proliferation, and impaired maturation of immature neurons. Klotho-deficient neurospheres show reduced proliferation and size that is rescued by supplementation with shed klotho protein. Conversely, 6-month-old klotho-overexpressing mice exhibit increased numbers of neural stem cells, increased proliferation, and more immature neurons with enhanced dendritic arborization. Protection from normal age-related loss of object location memory with klotho overexpression and loss of spatial memory when klotho is reduced by even half suggests direct, local effects of the protein. Together, these data show that klotho is a novel regulator of postnatal neurogenesis affecting neural stem cell proliferation and maturation sufficient to impact hippocampal-dependent spatial memory function.
Collapse
Affiliation(s)
- Ann M Laszczyk
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stephanie Fox-Quick
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hai T Vo
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dailey Nettles
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Phyllis C Pugh
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Gwendalyn D King
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
41
|
Active Dentate Granule Cells Encode Experience to Promote the Addition of Adult-Born Hippocampal Neurons. J Neurosci 2017; 37:4661-4678. [PMID: 28373391 DOI: 10.1523/jneurosci.3417-16.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 03/01/2017] [Accepted: 03/05/2017] [Indexed: 01/09/2023] Open
Abstract
The continuous addition of new dentate granule cells (DGCs), which is regulated exquisitely by brain activity, renders the hippocampus plastic. However, how neural circuits encode experiences to affect the addition of adult-born neurons remains unknown. Here, we used endoscopic Ca2+ imaging to track the real-time activity of individual DGCs in freely behaving mice. For the first time, we found that active DGCs responded to a novel experience by increasing their Ca2+ event frequency preferentially. This elevated activity, which we found to be associated with object exploration, returned to baseline by 1 h in the same environment, but could be dishabituated via introduction to a novel environment. To transition seamlessly between environments, we next established a freely controllable virtual reality system for unrestrained mice. We again observed increased firing of active neurons in a virtual enriched environment. Interestingly, multiple novel virtual experiences increased the number of newborn neurons accumulatively compared with a single experience. Finally, optogenetic silencing of existing DGCs during novel environmental exploration perturbed experience-induced neuronal addition. Our study shows that the adult brain conveys novel, enriched experiences to increase the addition of adult-born hippocampal neurons by increasing the firing of active DGCs.SIGNIFICANCE STATEMENT Adult brains are constantly reshaping themselves from synapses to circuits as we encounter novel experiences from moment to moment. Importantly, this reshaping includes the addition of newborn hippocampal neurons. However, it remains largely unknown how our circuits encode experience-induced brain activity to govern the addition of new hippocampal neurons. By coupling in vivo Ca2+ imaging of dentate granule neurons with a novel, unrestrained virtual reality system for rodents, we discovered that a new experience increased firing of active dentate granule neurons rapidly and robustly. Exploration in multiple novel virtual environments, compared with a single environment, promoted dentate activation and enhanced the addition of new hippocampal neurons accumulatively. Finally, silencing this activation optogenetically during novel experiences perturbed experience-induced neuronal addition.
Collapse
|
42
|
So JH, Huang C, Ge M, Cai G, Zhang L, Lu Y, Mu Y. Intense Exercise Promotes Adult Hippocampal Neurogenesis But Not Spatial Discrimination. Front Cell Neurosci 2017; 11:13. [PMID: 28197080 PMCID: PMC5281566 DOI: 10.3389/fncel.2017.00013] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 01/16/2017] [Indexed: 12/15/2022] Open
Abstract
Hippocampal neurogenesis persists throughout adult life and plays an important role in learning and memory. Although the influence of physical exercise on neurogenesis has been intensively studied, there is controversy in regard to how the impact of exercise may vary with its regime. Less is known about how distinct exercise paradigms may differentially affect the learning behavior. Here we found that, chronic moderate treadmill running led to an increase of cell proliferation, survival, neuronal differentiation, and migration. In contrast, intense running only promoted neuronal differentiation and migration, which was accompanied with lower expressions of vascular endothelial growth factor, brain-derived neurotrophic factor, insulin-like growth factor 1, and erythropoietin. In addition, the intensely but not mildly exercised animals exhibited a lower mitochondrial activity in the dentate gyrus. Correspondingly, neurogenesis induced by moderate but not intense exercise was sufficient to improve the animal’s ability in spatial pattern separation. Our data indicate that the effect of exercise on spatial learning is intensity-dependent and may involve mechanisms other than a simple increase in the number of new neurons.
Collapse
Affiliation(s)
- Ji H So
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and Technology Wuhan, China
| | - Chao Huang
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and Technology Wuhan, China
| | - Minyan Ge
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and Technology Wuhan, China
| | - Guangyao Cai
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and Technology Wuhan, China
| | - Lanqiu Zhang
- Tianjin Institute of Integrative Medicine for Acute Abdominal Disease, Nankai Hospital Tianjin, China
| | - Yisheng Lu
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and TechnologyWuhan, China; Institute of Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and TechnologyWuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and TechnologyWuhan, China
| | - Yangling Mu
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and TechnologyWuhan, China; Institute of Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and TechnologyWuhan, China; Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation, Huazhong University of Science and TechnologyWuhan, China
| |
Collapse
|
43
|
Tzeng WY, Wu HH, Wang CY, Chen JC, Yu L, Cherng CG. Sex Differences in Stress and Group Housing Effects on the Number of Newly Proliferated Cells and Neuroblasts in Middle-Aged Dentate Gyrus. Front Behav Neurosci 2017; 10:249. [PMID: 28119581 PMCID: PMC5220061 DOI: 10.3389/fnbeh.2016.00249] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 12/19/2016] [Indexed: 11/13/2022] Open
Abstract
Sex differences in stress and coping responses have been frequently documented in aged people, while whether such differences in aged people may appear at the middle age are unknown. This study was undertaken to study the impact of acute stress and social interaction on early neurogenesis in the dentate gyrus (DG) and hippocampus-related memory in two sexes of middle-aged mice. The number of newly proliferated cells, neuroblasts in DG, the object recognition and location memory in 9-month-old male and female C57BL/6N mice were assessed under baseline conditions as well as following an acute stressor regimen and group housing. Three conspecific companions, serving as "the housing group," were used to model the social interaction throughout the stressor regimen. Males had lower numbers of newly proliferated cells and neuroblasts under baseline conditions as compared to females. The stressor regimen caused rapid decreases in the number of newly proliferated cells and neuroblasts in female DG but no obvious changes were observed in male DG. Group housing, regardless of companions' age, prevented the stress-induced decreases in the number of newly proliferated cells and neuroblasts in female DG. In contrast, the presence of young or age-matched companions potentiated the stress effect in males by decreasing the number of newly proliferated cells and neuroblasts. Finally, neither the stressor regimen nor group housing affected mouse performances in the object recognition and location memory in either sex. These findings, taken together, provide evidence to support a notion that middle-aged females appear to demonstrate more stress susceptibility on early neurogenesis in DG as compared to middle-aged males, although the hippocampus-related memory performances are comparable and not affected by stress in these males and females. Experiencing stress, middle-aged females are more prone to benefit from social interaction as compared to middle-aged males in this regard. We suggest, accordingly, that involving social interaction may afford a therapeutic advance in preventing stress-produced decreases in early neurogenesis in middle-aged females' DG.
Collapse
Affiliation(s)
- Wen-Yu Tzeng
- Department of Physiology, National Cheng Kung University College of Medicine Tainan, Taiwan
| | - Hsin-Hua Wu
- Department of Physiology, National Cheng Kung University College of Medicine Tainan, Taiwan
| | - Ching-Yi Wang
- Institute of Basic Medical Sciences, National Cheng Kung University College of Medicine Tainan, Taiwan
| | - Jin-Chung Chen
- Graduate Institute of Biomedical Sciences, Chang Gung University Taoyuan, Taiwan
| | - Lung Yu
- Department of Physiology, National Cheng Kung University College of MedicineTainan, Taiwan; Institute of Basic Medical Sciences, National Cheng Kung University College of MedicineTainan, Taiwan
| | - Chianfang G Cherng
- Department of Health Psychology, Chang Jung Christian University Tainan, Taiwan
| |
Collapse
|
44
|
The effects of hormones and physical exercise on hippocampal structural plasticity. Front Neuroendocrinol 2016; 41:23-43. [PMID: 26989000 DOI: 10.1016/j.yfrne.2016.03.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/02/2016] [Accepted: 03/08/2016] [Indexed: 01/22/2023]
Abstract
The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration.
Collapse
|
45
|
Mahmoud R, Wainwright SR, Galea LAM. Sex hormones and adult hippocampal neurogenesis: Regulation, implications, and potential mechanisms. Front Neuroendocrinol 2016; 41:129-52. [PMID: 26988999 DOI: 10.1016/j.yfrne.2016.03.002] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/12/2016] [Accepted: 03/14/2016] [Indexed: 11/16/2022]
Abstract
Neurogenesis within the adult hippocampus is modulated by endogenous and exogenous factors. Here, we review the role of sex hormones in the regulation of adult hippocampal neurogenesis in males and females. The review is framed around the potential functional implications of sex hormone regulation of adult hippocampal neurogenesis, with a focus on cognitive function and mood regulation, which may be related to sex differences in incidence and severity of dementia and depression. We present findings from preclinical studies of endogenous fluctuations in sex hormones relating to reproductive function and ageing, and from studies of exogenous hormone manipulations. In addition, we discuss the modulating roles of sex, age, and reproductive history on the relationship between sex hormones and neurogenesis. Because sex hormones have diverse targets in the central nervous system, we overview potential mechanisms through which sex hormones may influence hippocampal neurogenesis. Lastly, we advocate for a more systematic consideration of sex and sex hormones in studying the functional implications of adult hippocampal neurogenesis.
Collapse
Affiliation(s)
- Rand Mahmoud
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Steven R Wainwright
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Liisa A M Galea
- Department of Psychology, University of British Columbia, Vancouver, Canada; Centre for Brain Health, University of British Columbia, Vancouver, Canada.
| |
Collapse
|
46
|
Social behavior, hormones and adult neurogenesis. Front Neuroendocrinol 2016; 41:71-86. [PMID: 26996817 DOI: 10.1016/j.yfrne.2016.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 01/31/2023]
Abstract
A variety of experiences have been shown to affect the production of neurons in the adult hippocampus. These effects may be mediated by experience-driven hormonal changes, which, in turn, interact with factors such as sex, age and life history to alter brain plasticity. Although the effects of physical experience and stress have been extensively characterized, various types of social experience across the lifespan trigger profound neuroendocrine changes in parallel with changes in adult neurogenesis. This review article focuses on the influence of specific social experiences on adult neurogenesis in the dentate gyrus and the potential role of hormones in these effects.
Collapse
|
47
|
Galea LAM, Frick KM, Hampson E, Sohrabji F, Choleris E. Why estrogens matter for behavior and brain health. Neurosci Biobehav Rev 2016; 76:363-379. [PMID: 27039345 PMCID: PMC5045786 DOI: 10.1016/j.neubiorev.2016.03.024] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 12/22/2022]
Abstract
The National Institutes of Health (NIH) has required the inclusion of women in clinical studies since 1993, which has enhanced our understanding of how biological sex affects certain medical conditions and allowed the development of sex-specific treatment protocols. However, NIH's policy did not previously apply to basic research, and the NIH recently introduced a new policy requiring all new grant applications to explicitly address sex as a biological variable. The policy itself is grounded in the results of numerous investigations in animals and humans illustrating the existence of sex differences in the brain and behavior, and the importance of sex hormones, particularly estrogens, in regulating physiology and behavior. Here, we review findings from our laboratories, and others, demonstrating how estrogens influence brain and behavior in adult females. Research from subjects throughout the adult lifespan on topics ranging from social behavior, learning and memory, to disease risk will be discussed to frame an understanding of why estrogens matter to behavioral neuroscience.
Collapse
Affiliation(s)
- Liisa A M Galea
- Department of Psychology, Centre for Brain Health, University of British Columbia, Vancouver, BC V6T1Z4, Canada.
| | - Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, United States
| | - Elizabeth Hampson
- Department of Psychology, University of Western Ontario, London, ON N6A 5C2, Canada
| | - Farida Sohrabji
- Department of Neuroscience and Experimental Therapeutics, Texas A&M HSC College of Medicine, Bryan, TX 77807, United States
| | - Elena Choleris
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, ON N1G 2W1, Canada
| |
Collapse
|
48
|
Social isolation increases cell proliferation in male and cell survival in female California mice (Peromyscus californicus). Physiol Behav 2015; 151:570-6. [DOI: 10.1016/j.physbeh.2015.08.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 05/28/2015] [Accepted: 08/29/2015] [Indexed: 11/23/2022]
|
49
|
Duarte-Guterman P, Yagi S, Chow C, Galea LAM. Hippocampal learning, memory, and neurogenesis: Effects of sex and estrogens across the lifespan in adults. Horm Behav 2015; 74:37-52. [PMID: 26122299 DOI: 10.1016/j.yhbeh.2015.05.024] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/29/2015] [Accepted: 05/26/2015] [Indexed: 01/12/2023]
Abstract
This article is part of a Special Issue "Estradiol and Cognition". There are sex differences in hippocampus-dependent cognition and neurogenesis suggesting that sex hormones are involved. Estrogens modulate certain forms of spatial and contextual memory and neurogenesis in the adult female rodent, and to a lesser extent male, hippocampus. This review focuses on the effects of sex and estrogens on hippocampal learning, memory, and neurogenesis in the young and aged adult rodent. We discuss how factors such as the type of estrogen, duration and dose of treatment, timing of treatment, and type of memory influence the effects of estrogens on cognition and neurogenesis. We also address how reproductive experience (pregnancy and mothering) and aging interact with estrogens to modulate hippocampal cognition and neurogenesis in females. Given the evidence that adult hippocampal neurogenesis plays a role in long-term spatial memory and pattern separation, we also discuss the functional implications of regulating neurogenesis in the hippocampus.
Collapse
Affiliation(s)
- Paula Duarte-Guterman
- Department of Psychology, Centre for Brain Health, Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Shunya Yagi
- Department of Psychology, Centre for Brain Health, Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Carmen Chow
- Department of Psychology, Centre for Brain Health, Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | - Liisa A M Galea
- Department of Psychology, Centre for Brain Health, Program in Neuroscience, University of British Columbia, Vancouver, Canada.
| |
Collapse
|
50
|
Ransome MI, Boon WC. Testosterone-induced adult neurosphere growth is mediated by sexually-dimorphic aromatase expression. Front Cell Neurosci 2015. [PMID: 26217181 PMCID: PMC4491627 DOI: 10.3389/fncel.2015.00253] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We derived adult neural stem/progenitor cells (NSPCs) from the sub-ventricular zone of male and female mice to examine direct responses to principal sex hormones. In the presence of epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF2) NSPCs of both sexes expressed nestin and sox2, and could be maintained as neurospheres without addition of any sex hormones. The reverse was not observed; neither testosterone (T), 17β-estradiol (E2) nor progesterone (P4) was able to support neurosphere growth in the absence of EGF and FGF2. Ten nanomolar T, E2 or P4 induced nestin(+) cell proliferation within 20 min and enhanced neurosphere growth over 7 days irrespective of sex, which was abolished by Erk inhibition with 20 μM U0126. Maintaining neurospheres with each sex hormone did not affect subsequent neuronal differentiation. However, 10 nM T, E2 or P4 added during differentiation increased βIII tubulin(+) neuron production with E2 being more potent compared to T and P4 in both sexes. Androgen receptor (AR) inhibition with 20 μM flutamide but not aromatase inhibition with 10 μM letrozole reduced basal and T-induced neurosphere growth in females, while only concurrent inhibition of AR and aromatase produced the same effect in males. This sex-specific effect was supported by higher aromatase expression in male neurospheres compared to females measured by Western blot and green fluorescent protein (GFP) reporter. Ten micromolar menadione induced oxidative stress, impaired neurosphere growth and up-regulated aromatase expression in both sexes. However, under oxidative stress letrozole significantly exacerbated impaired neurosphere growth in males only. While both E2 and T could prevent oxidative stress-induced growth reduction in both sexes, the effects of T were dependent on innate aromatase activity. We show for the first time that intrinsic androgen and estrogen signaling may impact the capacity of NSPCs to produce neural progenitors under pathological conditions of oxidative stress.
Collapse
Affiliation(s)
- Mark I Ransome
- Steroid Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia
| | - Wah Chin Boon
- Steroid Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health Parkville, VIC, Australia ; Department of Anatomy and Developmental Biology, Monash University Clayton, VIC, Australia
| |
Collapse
|