Project description:Cellular senescence is a hallmark of aging, and the accumulation of senescent cells (SnCs) accelerates the aging process and contributes to aging-related organ disorders. The PRDMs exhibit robust transcriptional regulatory activity and govern a wide range of biological processes. However, the role of PRDMs in cellular senescence and aging remain unclear. Here, we have demonstrated that PRDM16, among PRDMs, is decreased significantly in multiple organs of aged mice compared to young mice. Global Prdm16 deletion contributes to cellular senescence in various organs, including the kidney, heart, lung, brain hippocampus, stomach, and gut; subsequently leading to accelerated aging-related organ injury. Furthermore, tubular specific Prdm16 deletion aggravates irradiation induced kidney aging, and aging-related kidney disease subjected to ischemia reperfusion surgery. Exogenous PRDM16 gene delivery by lentivirus effectively attenuates cellular senescence in vitro and in vivo. Mechanistically, PRDM16 improves glutathione metabolism and inhibits oxidative DNA damage, the driving force of senescence. Especially, PRDM16 increases glutathione-S-transferase activity by upregulating the transcription of GSTM1. Transfection of GSTM1 restored cellular senescence and kidney aging caused by PRDM16 deficiency. Taken together, we provide a potential target for investigating the anti-aging therapy.
Project description:Cellular senescence is a hallmark of aging and the accumulation of senescent cells (SnCs) accelerates the aging process, contributing to aging-related organ disorders. The PRDF1 and RIZ1 homology domain (PRDM) protein exhibits robust transcriptional regulatory activities and governs a wide range of biological processes. However, its roles in cellular senescence remain unclear. Here, we demonstrated that PRDM16, a member of the PRDM protein family, decreased significantly in multiple organs of aged mice compared to young mice. Global Prdm16 deletion contributed to cellular senescence in various organs, including the kidneys, heart, lungs, hippocampus, stomach, and gut, leading to accelerated aging-related organ injury. Furthermore, tubular-specific Prdm16 deletion aggravated irradiation-induced kidney aging and aging-related kidney diseases in irradiated mice subjected to ischemia-reperfusion surgery. Exogenous PRDM16 gene delivery by lentivirus effectively attenuated cellular senescence in vitro and in vivo. Mechanistically, PRDM16 improved glutathione metabolism and inhibited oxidative DNA damage, which is a driving force of senescence. Specifically, PRDM16 upregulated the transcription of glutathione S-transferase mu 1 (GSTM1) by binding to its promoter region. Transfection with GSTM1 reversed PRDM16 deficiency-induced cellular senescence and kidney aging. Collectively, our results provide a potential target for the investigation of anti-aging therapies.
Project description:Gene expression profile from brown adipose tissues of Prdm16 knockout and wile type mice. Prdm16 is a transcription factor that regulates the thermogenic gene program in brown and beige adipocytes. However, whether Prdm16 is required for the development or physiological function of brown adipose tissue (BAT) in vivo has been unclear. By analyzing mice that selectively lacked Prdm16 in the brown adipose lineage, we found that Prdm16 was dispensable for embryonic BAT development. Brown adipose tissues were collected from Prdm16 knockout and wiletype mice with 4 biological replicates per condition. Experiment was done in two separate batch for 6-week-old and 11-month-old. Extracted RNA was hybridized to Agilent two-color arrays.
Project description:Prdm16 is a transcription factor that drives a complete program of brown adipocyte differentiation, but the mechanism by which Prdm16 activates gene transcription remains unknown. Utilizing ChIP-seq teqhnique, we found that Prdm16 binds to chromatin at/near many brown fat-selective genes in BAT. Interestingly, Prdm16-deficiency dramatically reduced the binding of Med1 to Prdm16-target sites. Indeed, Prdm16 binds and recruits Med1 to BAT-enriched genes and the loss of Prdm16 caused a fundamental change in chromatin architecture at key BAT-selective genes and also reduced transcirptional activity. Moreover, Prdm16, through its interaction with Med1, defines and regulates the activity of super-enhancers that drive the expression of cell identity genes. Together, these data demonstrate that Prdm16 drives gene transcription by recruiting Med1 to control chromatin architecture and super-enhancers. Brown adipose tissues were collected from Prdm16 knockout and wiletype 9-month-old mice and ChIP-seq was performed for Prdm16, PolII, Med1, and H3K27ac.
Project description:Microglia are essential to maintain brain homeostasis, but when dysregulated, exert pathogenic functions in Alzheimer’s disease (AD). Recent evidence has implicated senescent/dystrophic microglia in the pathological process of AD. Whether microglial senescence is a cause or consequence of AD pathogenesis however is unclear. Here we report that autophagy, a lysosomal degradation pathway, restricts cellular senescence of microglia and confer neuroprotection in AD mouse model. Autophagy-deficient microglia show hallmarks of cellular senescence evidenced by reduced proliferation, increased Cdkn1a/p21Cip, dystrophy, and typical secretory phenotype. While disease-associated microglia (DAM) surrounding amyloid plaques exhibit heightened autophagy, autophagy deficient, senescent microglia (SAM) disengage from and thus fail to limit the diffusive amyloid plaques, causing enhanced tau phosphorylation and neurotoxicity in AD model. Treatment of senolytic drugs removes senescent microglia and alleviates neuropathology. Our study demonstrates a causal role of autophagy impairment in microglial senescence and neurotoxicity and suggests therapeutic potential of senolytic treatment for AD.
Project description:Mutation of the PRDM16 gene causes human dilated and noncompaction cardiomyopathy. The PRDM16 protein is a transcriptional regulator that affects cardiac development via Tbx5 and Hand1, thus regulating myocardial structure. The biallelic inactivation of Prdm16 induces severe cardiac dysfunction with postnatal lethality and hypertrophy in mice. The early pathological events that occur upon Prdm16 inactivation have not been explored. This study performed in-depth pathophysiological and molecular analyses of male and female Prdm16csp1/wt mice that carry systemic, monoallelic Prdm16 gene inactivation. We systematically assessed early molecular changes through transcriptomics, proteomics, and metabolomics. Kinetic modelling of cardiac metabolism was performed in silico with CARDIOKIN.
Project description:Group 1 -- WT or PRDM16-KO ex vivo murine MLL-AF9 cells, and PRDM16-KO AF9 cells overexpressing either f-PRDM16 or s-PRDM16. Group 2 -- WT or total PRDM16-KO murine HSCs isolated from adult BM. Group 3 -- WT or total PRDM16-KO murine HSCs isolated from fetal liver. Group 4 -- WT or f-PRDM16-KO murine HSCs (expressing s-PRDM16 only) isolated from fetal liver.
Project description:PRDM16 ChIP was perfomed in control and Prdm16 KO crypts isolated from the duodenum of 6 week old mice 3 days after inducible gene deletion
Project description:PRDM16 is highly enriched in adult stem cells and plays a crucial role in multiple developmental processes. Here we demonstrate that PRDM16 is a histone H3K4 methyltransferase and this activity is essential for PRDM16 to function as a tumor suppressor. We show that PRDM16, through its regulation of transcription factor GFI1b, antagonizes the functions of MLL fusion proteins by repressing HOXA gene expression and therefore, specifically suppresses the transformation capability of MLL-AF9, MLL-AF6 and MLL-ENL. Furthermore, overexpression of PRDM16, but not the inactive PRDM16 mutant, blocks MLL mediated leukemogenesis while PRDM16 depletion significantly shortens the disease latency in vivo. We also show that PRDM16 activity is dynamically required at the pre-leukemic stage, but not in fully transformed leukemia, depicting a little known sequence of events necessary for clonal expansion during cancer evolution. Given the importance of PRDM16 and the loss of PRDM16 methyltransferase activity in an array of human malignancies, our findings provide broad insights for PRDM16-dependent physiological and pathological processes.