GSE160279
LARP7 ameliorates cellular senescence and aging-related atherosclerosis by allosterically enhancing SIRT1 deacetylase activity
Cell senescence is a cell state characterized with permanent cell cycle arrest and elevated proinflammatory secretome and associated with pleiotropic essential physiopathological processes. The persistent DNA damage response (DDR) is the major stress leading to senescence, however the molecular mechanism underling remains elusive. Here, we identified the La Ribonucleoprotein 7 (LARP7), a 7SK RNA binding protein, as a novel SIRT1 deacetylase activator. It directly interacted with SIRT1 allosteric regulatory domain and enhanced its deacetylase activity. DDR-mediated ATM activation trigged the extracellular shuttling and downregulation of LARP7 that dampened the SIRT1 deacetylase activity and enhanced p53 and NF?B (p65) transcriptional activity by augmenting their acetylation. As a consequence, activated p53 and NF?B arrested cell growth and promoted SASP genes expression, and thereby accelerated the cellular senescence. Inducible deletion of LARP7 in wildtype mouse led to senescent cell accumulation and premature ageing. Furthermore, we identified that ATM-LARP7-SIRT1-p53/NF?B senescent axis was active in the aortic senescence and atherogenesis. Genetic depletion of LARP7 aggravated the atherogenesis but conversely, inhibited ATM activation or restoring LARP7 expression with genetic manipulation alleviated the vascular aging and atherogenesis. Together, this study identifies LARP7 as a novel SIRT1 cellular activator and it's-mediated ATM-LARP7-SIRT1-p53/NF?B axis is attributed to DDR-mediated cellular senescence and aging-related pathologies. Overall design: We used RNA-seq to profile and compare the transcriptome in wildtype and  LARP7-depleted IMR90 cells and MEFs.