Microglia actively remodels adult hippocampal neurogenesis through the phagocytosis secretome
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PROVIDER: PRJNA532298 | ENA |
REPOSITORIES: ENA
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Project description:During adult hippocampal neurogenesis, the majority of newborn cells undergo apoptosis and are rapidly phagocytosed by resident microglia in order to avoid disturbing the surrounding neurons. Here, we propose that phagocytosis is not merely a passive process of corpse removal but has an active role in maintaining adult hippocampal neurogenesis. First, we found that neurogenesis was disrupted in three defective microglial phagocytosis KO models in vivo (P2Y12, MerTK/Axl , GPR34). We then followed an in vitro approach to perform a transcriptomic analysis of microglial phagocytosis and identified genes involved in metabolism, chromatin remodeling, and neurogenesis-related functions. Finally, we determined that the phagocytic microglia secretome limits the production of new neurons both in vivo and in vitro. Our data suggest that reprogrammed phagocytic microglia acts as a sensor of local cell death, modulating the balance between cell proliferation and cell survival in the neurogenic niche, supporting the long-term maintenance of adult hippocampal neurogenesis.
2020-04-09 | GSE129569 | GEO
Project description:During adult hippocampal neurogenesis, most newborn cells undergo apoptosis and are rapidly phagocytosed by resident microglia to prevent the spillover of intracellular contents. Here, we propose that phagocytosis is not merely passive corpse removal but has an active role in maintaining neurogenesis. First, we found that neurogenesis was disrupted in male and female mice chronically deficient for two phagocytosis pathways: the purinergic receptor P2Y12, and the tyrosine kinases of the TAM family Mer tyrosine kinase (MerTK)/Axl. In contrast, neurogenesis was transiently increased in mice in which MerTK expression was conditionally downregulated. Next, we performed a transcriptomic analysis of the changes induced by phagocytosis in microglia in vitro and identified genes involved in metabolism, chromatin remodeling, and neurogenesis-related functions. Finally, we discovered that the secretome of phagocytic microglia limits the production of new neurons both in vivo and in vitro Our data suggest that microglia act as a sensor of local cell death, modulating the balance between proliferation and survival in the neurogenic niche through the phagocytosis secretome, thereby supporting the long-term maintenance of adult hippocampal neurogenesis.SIGNIFICANCE STATEMENT Microglia are the brain professional phagocytes and, in the adult hippocampal neurogenic niche, they remove newborn cells naturally undergoing apoptosis. Here we show that phagocytosis of apoptotic cells triggers a coordinated transcriptional program that alters their secretome, limiting neurogenesis both in vivo and in vitro In addition, chronic phagocytosis disruption in mice deficient for receptors P2Y12 and MerTK/Axl reduces adult hippocampal neurogenesis. In contrast, inducible MerTK downregulation transiently increases neurogenesis, suggesting that microglial phagocytosis provides a negative feedback loop that is necessary for the long-term maintenance of adult hippocampal neurogenesis. Therefore, we speculate that the effects of promoting engulfment/degradation of cell debris may go beyond merely removing corpses to actively promoting regeneration in development, aging, and neurodegenerative diseases.
| S-EPMC7044727 | biostudies-literature
Project description:Oxidative stress is a major risk factor for Alzheimer’s disease (AD), which is characterized by brain atrophy, amyloid plaques, neurofibrillary tangles, and loss of neurons. 8-Oxoguanine, a major oxidatively generated nucleobase highly accumulated in the AD brain, is known to cause neurodegeneration. In mammalian cells, several enzymes play essential roles in minimizing the 8-oxoguanine accumulation in DNA. MUTYH with adenine DNA glycosylase activity excises adenine inserted opposite 8-oxoguanine in DNA. MUTYH is reported to actively contribute to the neurodegenerative process in Parkinson and Huntington diseases and some mouse models of neurodegenerative diseases by accelerating neuronal dysfunction and microgliosis under oxidative conditions; however, whether or not MUTYH is involved in AD pathogenesis remains unclear. In the present study, we examined the contribution of MUTYH to the AD pathogenesis. Using postmortem human brains, we showed that various types of MUTYH transcripts and proteins are expressed in most hippocampal neurons and glia in both non-AD and AD brains. We further introduced MUTYH deficiency into AppNL-G-F/NL-G-F knock-in AD model mice, which produce humanized toxic amyloid-β without the overexpression of APP protein, and investigated the effects of MUTYH deficiency on the behavior, pathology, gene expression, and neurogenesis. MUTYH deficiency improved memory impairment in AppNL-G-F/NL-G-F mice, accompanied by reduced microgliosis. Gene expression profiling strongly suggested that MUTYH is involved in the microglial response pathways under AD pathology and contributes to the phagocytic activity of disease-associated microglia. We also found that MUTYH deficiency ameliorates impaired neurogenesis in the hippocampus, thus improving memory impairment. In conclusion, we propose that MUTYH, which is expressed in the hippocampus of AD patients as well as non-AD subjects, actively contributes to memory impairment by inducing microgliosis with poor neurogenesis in the preclinical AD phase and that MUTYH is a novel therapeutic target for AD, as its deficiency is highly beneficial for ameliorating AD pathogenesis.
2021-12-23 | GSE157766 | GEO
Project description:MUTYH Actively Contributes to Microglial Activation and Impaired Neurogenesis in the Pathogenesis of Alzheimer’s Disease
| PRJNA662708 | ENA
Project description:Aging coincides with the progressive loss of muscle mass and strength, increased adiposity, and diminished physical function. Accordingly, interventions aimed at improving muscle, metabolic, and/or physical health are of interest to mitigate the adverse effects of aging. In this study, we tested a stem-cell secretome product which contains a host of growth, cytoskeletal remodeling, and immunomodulatory factors. We examined the effects of 4 weeks of bi-weekly unilateral intramuscular secretome injections (quadriceps) in ambulatory aged male C57Bl/6 mice (22-23 months) compared to saline injected aged-matched controls. After 4 weeks of treatment, secretome delivery substantially increased whole body lean mass and decreased fat mass corresponding to higher fiber cross sectional area and smaller adipocyte size, respectively. Secretome-treated mice also displayed improved whole-body grip strength and rotarod performance and had higher energy expenditure and physical activity levels compared to control mice. Furthermore, secretome-treated mice had greater skeletal muscle Pax7+ cell abundance, capillary density, and collagen turnover. Finally, the secretome product reduced lipid content and lipid droplet size in adipocytes in vitro. These data suggest intramuscular treatment secretome improves whole-body metabolism, physical function, and remodels skeletal muscle and adipose tissue in aged mice.
2024-07-31 | GSE242211 | GEO
Project description:Apoptosis accounts for ~ 90% of homeostatic cell turnover in the body1. While caspase-dependent apoptosis is known to influence immune tolerance, induction of cell proliferation, and tissue regeneration2-4, how these apoptotic cells contribute to such diverse effects is less understood. Soluble factors released from apoptotic cells could be a means of ‘talking’ to healthy cells in the tissue neighborhood. While a few phagocyte-attracting ‘find-me’ signals released from apoptotic cells are known5, the larger ‘metabolite secretome’ from apoptotic cells is not yet defined. Here, via unbiased profiling of the apoptotic cell secretome, we identified 123 metabolites that are specifically released during apoptosis, while cells still retain membrane integrity. Release of ~25 of these metabolites is dependent on Pannexin 1 (Panx1) channels, which are opened by caspase-dependent cleavage during apoptosis. Interestingly, one of the Panx1-dependent metabolites from apoptotic cells is spermidine, a polyamine whose release could be, in part, due to the continued metabolic activity of dying cells. RNAseq analysis of healthy cells exposed to the apoptotic secretome revealed Panx1-dependent gene programs, including genes linked to suppression of inflammation, cell proliferation, and wound healing. Analysis of the apoptotic secretome across cell types and different apoptotic stimuli, identified a core “set” of 8 Panx1-dependent metabolites. Strikingly, a selected cocktail of these metabolites demonstrated significant immunosuppressive effects by potently reducing disease severity in an inflammatory arthritis model and a lung graft rejection model. Collectively, these data advance the concept that apoptotic cells are not ‘inert’ corpses waiting for removal by phagocytes, but rather they actively communicate with the tissue environment through their metabolite secretome, with implications in tissue inflammation.
2020-03-19 | GSE131906 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE33092: Oncogenic BRAFV600E remodels the melanocyte transcriptome and induces BLNCR1 to regulate melanoma cell migration [HT-seq] GSE37132: Oncogenic BRAFV600E remodels the melanocyte transcriptome and induces BLNCR1 to regulate melanoma cell migration [Affymetrix] Refer to individual Series
2012-04-27 | E-GEOD-37169 | biostudies-arrayexpress
Project description:Toxoplasma gondii infection triggers host microtubule rearrangement and organelle recruitment around the parasite vacuole. Factors affecting initial stages of microtubule remodeling are unknown. To illuminate the mechanism, we tested the hypothesis that the parasite actively remodels host microtubules. Utilizing heat-killed parasites and time-lapse analysis, we determined microtubule rearrangement requires living parasites and is time dependent. We discovered a novel aster of microtubules (MTs) associates with the vacuole within 1h of infection. This aster lacks the concentrated foci of gamma (gamma)-tubulin normally associated with MT nucleation sites. Unexpectedly, vacuole enlargement does not correlate with an increase in MT staining around the vacuole. We conclude microtubule remodeling does not result from steric constraints. Using nocodazole washout studies, we demonstrate the vacuole nucleates host microtubule growth in-vivo via gamma-tubulin-associated sites. Moreover, superinfected host cells display multiple gamma-tubulin foci. Microtubule dynamics are critical for cell cycle control in uninfected cells. Using non-confluent monolayers, we show host cells commonly fail to finish cytokinesis resulting in larger, multinucleated cells. Our data suggest intimate interactions between T. gondii and host microtubules result in suppression of cell division and/or cause a mitotic defect, thus providing a larger space for parasite duplication.
| S-EPMC2765197 | biostudies-literature
Project description:We found the bone marrow stromal-derived neural progenitor cells secretome have the neural protection effect. Proteomic analysis was performed nn order to analyze the protection factor in the secretome. Keywords: Neural protection, secretome
2008-10-18 | GSE13242 | GEO