scholarly journals Suppressor of Fused controls perinatal expansion and quiescence of future dentate adult neural stem cells

2018 ◽  
Author(s):  
Hirofumi Noguchi ◽  
Jesse Garcia Castillo ◽  
Kinichi Nakashima ◽  
Samuel J. Pleasure

AbstractAdult hippocampal neurogenesis requires the quiescent neural stem cell (NSC) pool to persist lifelong. The establishment and maintenance of quiescent NSC pools during development is not understood. Here we show that Suppressor of Fused (Sufu) controls establishment of the quiescent NSC pool during mouse dentate gyrus (DG) development through regulation of Sonic Hedgehog (Shh) signaling. Deletion of Sufuin NSCs at the beginning of DG development decreases Shh signaling leading to reduced proliferation of NSCs, resulting in a small quiescent NSC pool in adult mice. We found that putative adult NSCs proliferate and increase their numbers in the first postnatal week and subsequently become quiescent towards the end of the first postnatal week. In the absence of Sufu, postnatal expansion of NSCs is compromised, and NSCs prematurely become quiescent. Thus, Sufu is required for Shh signaling activity ensuring the expansion and proper transition of NSC pools to quiescence during DG development.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Hirofumi Noguchi ◽  
Jesse Garcia Castillo ◽  
Kinichi Nakashima ◽  
Samuel J Pleasure

Adult hippocampal neurogenesis requires the quiescent neural stem cell (NSC) pool to persist lifelong. However, establishment and maintenance of quiescent NSC pools during development is not understood. Here, we show that Suppressor of Fused (Sufu) controls establishment of the quiescent NSC pool during mouse dentate gyrus (DG) development by regulating Sonic Hedgehog (Shh) signaling activity. Deletion of Sufu in NSCs early in DG development decreases Shh signaling activity leading to reduced proliferation of NSCs, resulting in a small quiescent NSC pool in adult mice. We found that putative adult NSCs proliferate and increase their numbers in the first postnatal week and subsequently enter a quiescent state towards the end of the first postnatal week. In the absence of Sufu, postnatal expansion of NSCs is compromised, and NSCs prematurely become quiescent. Thus, Sufu is required for Shh signaling activity ensuring expansion and proper transition of NSC pools to quiescent states during DG development.


2019 ◽  
Vol 116 (27) ◽  
pp. 13651-13660 ◽  
Author(s):  
Yi-Ting Su ◽  
Shun-Fat Lau ◽  
Jacque P. K. Ip ◽  
Kit Cheung ◽  
Tom H. T. Cheung ◽  
...  

Adult hippocampal neurogenesis involves the lifelong generation of neurons. The process depends on the homeostasis of the production of neurons and maintenance of the adult neural stem cell (NSC) pool. Here, we report that α2-chimaerin, a Rho GTPase-activating protein, is essential for NSC homeostasis in adult hippocampal neurogenesis. Conditional deletion of α2-chimaerin in adult NSCs resulted in the premature differentiation of NSCs into intermediate progenitor cells (IPCs), which ultimately depleted the NSC pool and impaired neuron generation. Single-cell RNA sequencing and pseudotime analyses revealed that α2-chimaerin–conditional knockout (α2-CKO) mice lacked a unique NSC subpopulation, termed Klotho-expressing NSCs, during the transition of NSCs to IPCs. Furthermore, α2-CKO led to defects in hippocampal synaptic plasticity and anxiety/depression-like behaviors in mice. Our findings collectively demonstrate that α2-chimaerin plays an essential role in adult hippocampal NSC homeostasis to maintain proper brain function.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3776-3776 ◽  
Author(s):  
Alice Y Shih ◽  
Annelie Schairer ◽  
Christian L Barrett ◽  
Ifat Geron ◽  
Angela C Court Recart ◽  
...  

Abstract Abstract 3776 Cumulative evidence suggests that dormant self-renewing leukemia stem cells (LSC) contribute to relapse and blast crisis transformation by evading therapies that target cycling cells. Previously, sonic hedgehog (Shh) signaling was shown to modulate cell cycle regulation and self-renewal in normal mouse hematopoietic stem cells. However, its role in human LSC regeneration and quiescence had not been elucidated. Here we investigated the role of Shh signaling in maintenance of dormancy. We show that, compared to chronic phase CML and normal progenitors, human blast crisis LSC harbor enhanced expression of the Shh transcriptional activator, GLI2, and decreased expression of a transcriptional repressor, GLI3. Treatment of human blast crisis LSC engrafted RAG2−/−gc−/− mice with a selective Shh inhibitor, PF-04449913, reduced leukemic burden in a niche-dependent manner commensurate with GLI downregulation. Full transcriptome RNA sequencing performed on FACS-purified human progenitors from PF-04449913 treated blast crisis LSC engrafted mice demonstrated greater Shh gene splice isoform concordance with normal progenitors than vehicle treated controls. In addition, RNA sequencing revealed significantly decreased cell cycle regulatory genes expression and splice isoform analysis demonstrated reversion towards a normal splice isoform signature for many cell cycle regulatory genes. Moreover, cell cycle FACS analysis showed that selective Shh inhibition permitted dormant blast crisis LSC to enter the cell cycle while normal progenitor cell cycle status was unaffected. Finally, PF-04449913 synergized with BCR-ABL inhibition to reduce blast crisis LSC survival and self-renewal in concert with increased expression of Shh pathway regulators. Our findings suggest that selective Shh antagonism induces cycling of dormant human blast crisis LSC, rendering them susceptible to BCR-ABL inhibition, while sparing normal progenitors. Implementation of novel LSC splice isoform detection platforms to assess efficacy of Shh inhibitor-mediated sensitization to molecularly targeted therapy may inform dormant cancer stem cell elimination strategies that ultimately avert relapse. Disclosures: Levin: Pfizer Oncology: Employment; Pfizer Oncology: Equity Ownership.


2018 ◽  
Author(s):  
Mary Youssef ◽  
Varsha S. Krish ◽  
Greer S. Kirshenbaum ◽  
Piray Atsak ◽  
Tamara J. Lass ◽  
...  

AbstractEnvironmental exposures during early life, but not during adolescence or adulthood, lead to persistent reductions in neurogenesis in the adult hippocampal dentate gyrus (DG). The mechanisms by which early life exposures lead to long-term deficits in neurogenesis remain unclear. Here, we investigated whether targeted ablation of dividing neural stem cells during early life is sufficient to produce long-term decreases in DG neurogenesis. Having previously found that the stem cell lineage is resistant to long-term effects of transient ablation of dividing stem cells during adolescence or adulthood (Kirshenbaum et al., 2014), we used a similar pharmacogenetic approach to target dividing neural stem cells for elimination during early life periods sensitive to environmental insults. We then assessed the Nestin stem cell lineage in adulthood. We found that the adult neural stem cell reservoir was depleted following ablation during the first postnatal week, when stem cells were highly proliferative, but not during the third postnatal week, when stem cells were more quiescent. Remarkably, ablating proliferating stem cells during either the first or third postnatal week led to reduced adult neurogenesis out of proportion to the changes in the stem cell pool, indicating a disruption of the stem cell function or niche following stem cell ablation in early life. These results highlight the first three postnatal weeks as a series of sensitive periods during which elimination of dividing stem cells leads to lasting alterations in adult DG neurogenesis and stem cell function. These findings contribute to our understanding of the relationship between DG development and adult neurogenesis, as well as suggest a possible mechanism by which early life experiences may lead to lasting deficits in adult hippocampal neurogenesis.


2019 ◽  
Author(s):  
Vijay S Adusumilli ◽  
Tara L Walker ◽  
Rupert W Overall ◽  
Gesa M Klatt ◽  
Salma A Zeidan ◽  
...  

SummaryIntracellular redox states regulate the balance between stem cell maintenance and activation. Increased levels of reactive oxygen species (ROS) are linked to proliferation and lineage specification. In contrast to this general principle, we show that in the hippocampus of adult mice it is the quiescent neural stem cells (NSCs) that maintain the highest ROS levels (hiROS). Classifying NSCs based on intracellular ROS content identified subpopulations with distinct molecular profiles, corresponding to functional states. Shifts in ROS content primed cells for a subsequent transition of cellular state, with lower cellular ROS content marking activity and differentiation. Physical activity, a known physiological activator of adult hippocampal neurogenesis, recruited the quiescent hiROS NSCs into proliferation via a transient Nox2-dependent ROS surge. In the absence of Nox2, baseline neurogenesis was unaffected, but the activity-induced increase in proliferation disappeared. These results describe a novel mechanism linking the modulation of cellular ROS by behavioral cues to the maintenance and activation of adult NSCs.HighlightsQuiescent adult hippocampal stem cells are characterized by high intracellular ROSChanges in intracellular ROS content precede changes in cellular stateAcute physical activity recruits quiescent cells into active proliferationThis recruitment is marked by a Nox2-dependent ROS spike in hiROS stem cells and represents an independent mode of cell cycle entryGraphical Abstract


Stem Cells ◽  
2016 ◽  
Vol 34 (8) ◽  
pp. 2194-2209 ◽  
Author(s):  
Vanesa Nieto-Estévez ◽  
Carlos O. Oueslati-Morales ◽  
Lingling Li ◽  
James Pickel ◽  
Aixa V. Morales ◽  
...  

2020 ◽  
Vol 117 (41) ◽  
pp. 25818-25829
Author(s):  
Xinxing Wang ◽  
Hanxiao Liu ◽  
Johannes Morstein ◽  
Alexander J. E. Novak ◽  
Dirk Trauner ◽  
...  

Hippocampus-engaged behaviors stimulate neurogenesis in the adult dentate gyrus by largely unknown means. To explore the underlying mechanisms, we used tetrode recording to analyze neuronal activity in the dentate gyrus of freely moving adult mice during hippocampus-engaged contextual exploration. We found that exploration induced an overall sustained increase in inhibitory neuron activity that was concomitant with decreased excitatory neuron activity. A mathematical model based on energy homeostasis in the dentate gyrus showed that enhanced inhibition and decreased excitation resulted in a similar increase in neurogenesis to that observed experimentally. To mechanistically investigate this sustained inhibitory regulation, we performed metabolomic and lipidomic profiling of the hippocampus during exploration. We found sustainably increased signaling of sphingosine-1-phosphate, a bioactive metabolite, during exploration. Furthermore, we found that sphingosine-1-phosphate signaling through its receptor 2 increased interneuron activity and thus mediated exploration-induced neurogenesis. Taken together, our findings point to a behavior-metabolism circuit pathway through which experience regulates adult hippocampal neurogenesis.


2016 ◽  
Vol 57 (3) ◽  
pp. 171-184 ◽  
Author(s):  
Sehee Kim ◽  
Chanyang Kim ◽  
Seungjoon Park

Adult hippocampal neurogenesis is decreased in type 2 diabetes, and this impairment appears to be important in cognitive dysfunction. Previous studies suggest that ghrelin gene products (acylated ghrelin (AG), unacylated ghrelin (UAG) and obestatin (OB)) promote neurogenesis. Therefore, we hypothesize that ghrelin gene products may reduce the harmful effects of high glucose (HG) on hippocampal neural stem cells (NSCs). The aim of this study was to investigate the role of these peptides on the survival of cultured hippocampal NSCs exposed to HG insult. Treatment of hippocampal NSCs with AG, UAG or OB inhibited HG-induced cell death and apoptosis. Exposure of cells to the growth hormone secretagogue receptor 1a antagonist abolished the protective effects of AG against HG toxicity, whereas those of UAG or OB were preserved. All three peptides attenuated HG-induced decrease in BrdU-labeled and phosphohistone-H3-labeled cells. We also investigated the effects of ghrelin gene products on the regulation of apoptosis at the mitochondrial level. AG, UAG or OB rescued hippocampal NSCs from HG insult by inhibiting intracellular and mitochondrial reactive oxygen species generation and stabilizing mitochondrial transmembrane potential. In addition, cells treated with ghrelin gene products showed an increased Bcl-2 and decreased Bax levels, thereby increasing the Bcl-2/Bax ratio, inhibiting cytochrome c release and preventing caspase-3 activation. Finally, AG-, UAG- or OB-mediated protection was dependent on the activities of adenosine monophosphate-activated protein kinase/uncoupling protein 2 pathway. Our data indicate that ghrelin gene products may act as survival factors that preserve mitochondrial function and inhibit oxidative stress-induced apoptosis.


Blood ◽  
2011 ◽  
Vol 118 (9) ◽  
pp. 2420-2429 ◽  
Author(s):  
Christoph Schaniel ◽  
Dario Sirabella ◽  
Jiajing Qiu ◽  
Xiaohong Niu ◽  
Ihor R. Lemischka ◽  
...  

Abstract The role of Wnt signaling in hematopoietic stem cell fate decisions remains controversial. We elected to dysregulate Wnt signaling from the perspective of the stem cell niche by expressing the pan Wnt inhibitor, Wnt inhibitory factor 1 (Wif1), specifically in osteoblasts. Here we report that osteoblastic Wif1 overexpression disrupts stem cell quiescence, leading to a loss of self-renewal potential. Primitive stem and progenitor populations were more proliferative and elevated in bone marrow and spleen, manifesting an impaired ability to maintain a self-renewing stem cell pool. Exhaustion of the stem cell pool was apparent only in the context of systemic stress by chemotherapy or transplantation of wild-type stem cells into irradiated Wif1 hosts. Paradoxically this is mediated, at least in part, by an autocrine induction of canonical Wnt signaling in stem cells on sequestration of Wnts in the environment. Additional signaling pathways are dysregulated in this model, primarily activated Sonic Hedgehog signaling in stem cells as a result of Wif1-induced osteoblastic expression of Sonic Hedgehog. We find that dysregulation of the stem cell niche by overexpression of an individual component impacts other unanticipated regulatory pathways in a combinatorial manner, ultimately disrupting niche mediated stem cell fate decisions.


2015 ◽  
Vol 35 (5) ◽  
pp. 2019-2032 ◽  
Author(s):  
Wei Cheng ◽  
Pingping Yu ◽  
Li Wang ◽  
Changbo Shen ◽  
Xiaosong Song ◽  
...  

Background/Aims: There is interest in drugs and rehabilitation methods to enhance neurogenesis and improve neurological function after brain injury or degeneration. Resveratrol may enhance hippocampal neurogenesis and improve hippocampal atrophy in chronic fatigue mice and prenatally stressed rats. However, its effect and mechanism of neurogenesis after stroke is less well understood. Sonic hedgehog (Shh) signaling is crucial for neurogenesis in the embryonic and adult brain, but relatively little is known about the role of Shh signaling in resveratrol-enhanced neurogenesis after stroke. Methods: Neural stem cells (NSCs) before oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro were pretreated with resveratrol with or without cyclopamine. Survival and proliferation of NSCs was assessed by the CCK8 assay and BrdU immunocytochemical staining. The expressions and activity of signaling proteins and mRNAs were detected by immunocytochemistry, Western blotting, and RT-PCR analysis. Results: Resveratrol significantly increased NSCs survival and proliferation in a concentration-dependent manner after OGD/R injury in vitro. At the same time, the expression of Patched-1, Smoothened (Smo), and Gli-1 proteins and mRNAs was upregulated, and Gli-1 entered the nucleus, which was inhibited by cyclopamine, a Smo inhibitor. Conclusion: Shh signaling mediates resveratrol to increase NSCs proliferation after OGD/R injury in vitro.


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