LARP7, a new ROS sensor, protects against heart failure by enhancing mitochondrial biogenesis
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ABSTRACT:
PROVIDER: PRJNA655954 | ENA |
REPOSITORIES: ENA
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Project description:LARP7 controls the SIRT1 activity and homeostasis, which is essential for mitochondrial biogenesis, energy production and cardiac function. The deprivation of LARP7 resulted from the activation ATM pathway attenuates the mitochondrial function and biogenesis and leads to the cardiomyopathy and heart failure. Method: Heart morphology and functions were assessed by gross anatomy, serial echocardiography and histology on sections; Mitochondrial morphology and activity were evaluated by TEM and seahorse assays. The therapeutic potential of LARP7 in heart failure was evaluated in mouse myocardial infarction model either with AAV9 infection or pharmacological inhibitor.
2020-08-14 | GSE155898 | GEO
Project description: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 NFB (p65) transcriptional activity by augmenting their acetylation. As a consequence, activated p53 and NFB 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/NFB 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/NFB axis is attributed to DDR-mediated cellular senescence and aging-related pathologies.
2021-10-30 | GSE160279 | GEO
Project description:PML is a ROS sensor activating p53 upon oxidative stress
| PRJNA392300 | ENA
Project description:PML nuclear bodies (NBs) recruit partner proteins -including p53 and its regulators- controlling their abundance or function. Investigating arsenic sensitivity of acute promyelocytic leukemia, we proposed that PML oxidation promotes NB-biogenesis. Yet, physiological links between PML and oxidative stress response in vivo remain unexplored. Here we identify PML as a reactive oxygen species (ROS) sensor. Pml-/- cells accumulate ROS, while PML expression decreases ROS levels. Unexpectedly, Pml-/- embryos survive acute glutathione depletion. Moreover, Pml-/- animals are resistant to acetaminophen hepatotoxicity or fasting-induced steatosis. Molecularly, Pml-/- animals fail to properly activate oxidative stress-responsive p53 targets, while NRF2 response is accelerated. Finally, in an oxidative stress-prone background, Pml-/- animals display a longevity phenotype, likely reflecting decreased basal p53 activation. Thus, similar to p53, PML exerts basal anti-oxidant properties, but also drives oxidative stress-induced changes in cell survival/proliferation or metabolism in vivo. Through NB-biogenesis, PML therefore couples ROS-sensing to p53 responses, shedding a new light on PML role in senescence or stem cell biology.
2017-09-22 | GSE103642 | GEO
Project description:Impaired DNA repair leads to cancer, aging and many genetic diseases. However, understanding of the complexity of DNA is far from complete, resulting in the failure of therapies using genotoxic reagents. Here, we found that LARP7, an RNA-binding protein known to stabilize 7SK RNA, was degraded after DNA injury caused by ionizing radiation and chemotherapy. The LARP7 degradation was catalyzed by an E3 ligase complex of BRCA1 and BARD1 that was triggered by ATM-mediated phosphorylation. LARP7 depletion caused transcriptional repression of the cell cycle regulators CCNB1, CCNB2 and CDK1; this repression arrested cells before the G2/M DNA damage checkpoint and reduced BRCA2 phosphorylation, therefore enhancing Rad51 recruitment and ultimately ensuring the homologous repair of damaged DNA. Importantly, the increased DNA damage repair capacity induced by LARP7 depletion caused resistance to ionizing radiation and CDDP treatment in both wild-type and BRCA1-mutant breast cancer cells and in mouse xenografts. Such resistance also contributed to reduced relapse-free survival rates in breast cancer patients with low levels of LARP7 after chemotherapy. Taken together, the results of this study show that LARP7 coordinates cell cycle progression and faithful DNA repair. We suggest that this mechanism could be exploited to prevent tumorigenesis and improve the effectiveness of cancer therapies.
2019-01-01 | GSE124393 | GEO
Project description:The La-related protein LARP7 has been mainly described as a component of the 7SK small nuclear ribonucleoprotein (snRNP) complex, which negatively regulates RNA polymerase II by sequestering the positive transcription elongation factor b (P-TEFb). In our studies, we discovered a novel, 7SK snRNP-independent function of LARP7. We show that LARP7 interacts with the U6 spliceosomal RNA as well as with the small nucleolar RNAs (snoRNAs) directing the 2'-O-methylations of U6. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primordial dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.
2020-02-03 | GSE126592 | GEO
Project description:Anti-LARP7 RNA immunoprecipitation (RIP) coupled with RNA-seq assays showed significant enrichment of U6 snRNA, but not other 4 spliceosomal snRNAs, in LARP7 complexes in adult mouse testis.
2019-11-07 | GSE128831 | GEO
Project description:LARP7 ameliorates cellular senescence and aging-related atherosclerosis by allosterically enhancing SIRT1 deacetylase activity
| PRJNA672873 | ENA
Project description:LARP7 plays a pivotal role in regulating endothelial-to-mesenchymal transition(EndMT) and EndMT-associated heart valve formation. LARP7 directly interactes with TRIM28 and cooperatively represses SLUG transcription, which thereby suppresses EndMT of endothelial cells. More importantly, inducible knockout of LARP7 or TRIM28 in the endocardium promotes EndMT in vivo and leads to the valvular hyperplasia.
2023-09-22 | GSE165400 | GEO
Project description:The La-related protein LARP7 has been mainly described as a component of the 7SK small nuclear ribonucleoprotein (snRNP) complex, which negatively regulates RNA polymerase II by sequestering the positive transcription elongation factor b (P-TEFb). In our studies, we discovered a novel, 7SK snRNP-independent function of LARP7. We show that LARP7 interacts with the U6 spliceosomal RNA as well as with the small nucleolar RNAs (snoRNAs) directing the 2'-O-methylations of U6. Importantly, in the absence of LARP7, significantly less 2'-O-methylations are deposited on U6 affecting splicing fidelity. Mutations in the LARP7 gene have been associated with the Alazami syndrome, a form of primordial dwarfism characterized by intellectual disability. We describe a novel loss-of-function mutation of LARP7 occurring in Alazami patients and detect reduced 2'-O-methylations of U6 in patient-derived samples. Thus, aberrant posttranscriptional RNA modifications of the spliceosomal U6 snRNA may contribute to the development of this severe disease.
2020-02-03 | GSE126682 | GEO