The Senescence-associated Secretome of Hedgehog-deficient Hepatocytes Drives MASLD Progression
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PROVIDER: PRJNA1142044 | ENA |
REPOSITORIES: ENA
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Project description:The burden of senescent hepatocytes correlates with MASLD severity but mechanisms driving senescence, and how it exacerbates MASLD are poorly understood. Hepatocytes become senescent when Smoothened (Smo) is deleted to disrupt Hedgehog signaling. We aimed to determine if the secretomes of Smo-deficient hepatocytes perpetuate senescence to drive MASLD progression. RNA seq analysis confirmed that hepatocyte populations of MASLD livers are depleted of Smo(+) cells and enriched with senescent cells. When fed CDA-HFD, Smo(-) mice had lower antioxidant markers and developed worse DNA damage, senescence, MASH and liver fibrosis than Smo(+) mice. Sera and hepatocyte-conditioned medium from Smo(-) mice were depleted of thymidine phosphorylase (TP), a protein that maintains mitochondrial fitness. Treating Smo(-) hepatocytes with TP reduced senescence and lipotoxicity; inhibiting TP in Smo(+) hepatocytes had the opposite effects and exacerbated hepatocyte senescence, MASH, and fibrosis in CDA-HFD-fed mice.Therefore, we found that inhibiting Hedgehog signaling in hepatocytes promotes MASLD by suppressing hepatocyte production of proteins that prevent lipotoxicity and senescence.
2024-10-01 | GSE273523 | GEO
Project description:NAD+ metabolism governs proinflammatory senescence secretome
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Project description:During the progression of type 1 diabetes (T1D), β-cells are exposed to significant stress and therefore require adaptive responses to survive. The adaptive mechanisms that can preserve β-cell function and survival in the face of autoimmunity remain unclear. Here we show that deletion of the unfolded protein response genes, Atf6α or Ire1α, in β-cells of NOD mice prior to insulitis generates a p21-driven early senescence phenotype and altered β-cell secretome that significantly enhances leukemia inhibitory factor-mediated recruitment of M2 macrophages to the islets. Consequently, M2 macrophages promote anti-inflammatory responses and immune surveillance that cause resolution of islet inflammation, removal of terminally senesced β-cells, reduction of β-cell apoptosis, and prevention of T1D. We further demonstrate that p21-mediated early senescence signature is conserved in residual β-cells of T1D patients. Our findings reveal a previously unrecognized link between β-cell UPR and senescence that, if leveraged, may represent a novel therapeutic strategy for T1D.
2023-11-20 | GSE239947 | GEO
Project description:Older age is a major risk factor for damage to many tissues, including liver. Aging undermines resiliency (i.e., the ability to recover from injury) and impairs liver regeneration. The mechanisms whereby aging reduces resiliency are poorly understood. Hedgehog is a signaling pathway with critical mitogenic and morphogenic functions during development. Recent studies indicate that Hedgehog regulates metabolic homeostasis in adult liver. The present study evaluates the hypothesis that Hedgehog signaling becomes dysregulated in hepatocytes during aging, resulting in decreased resiliency and therefore, impaired regeneration and enhanced vulnerability to damage. Methods: Partial hepatectomy (PH) was performed on young and old wild type mice and Smoothened (Smo)-floxed mice treated with AAV8-TBG luciferase (control) or AAV8-TBG-Cre vectors to conditionally delete Smo and disrupt Hedgehog signaling specifically in hepatocytes. Changes in signaling were correlated with changes in regenerative responses and compared among groups. Results: Old livers had fewer hepatocytes proliferating after PH. RNA sequencing identified Hedgehog as a top down-regulated pathway in old hepatocytes before and after the regenerative challenge. Deleting Smo in healthy young hepatocytes before PH prevented Hedgehog pathway activation after PH and inhibited regeneration. GO analysis demonstrated that both old and Smo-deleted young hepatocytes had activation of pathways involved in innate immune responses and suppression of several signaling pathways that control liver growth and metabolism including insulin-like growth factor, Wnt and NOTCH. Hedgehog inhibition promoted telomere shortening and mitochondrial dysfunction in hepatocytes, consequences of aging that promote inflammation and impair tissue growth and metabolic homeostasis. Conclusion: Hedgehog signaling is dysregulated in old hepatocytes. This accelerates aging, resulting in decreased resiliency and therefore, impaired liver regeneration and enhanced vulnerability to damage.
2021-10-15 | GSE181761 | GEO
Project description:Hepatocytes undergo senescence during development and progression of NAFLD. In order to better understand the phenotype of these senescent cells we generated an in vitro model of stress-induced senescence in IHH cells. To further understand the dynamic regulation of paracrine senescence, IHH cells were exposed to conditioned medium generated by an inducible model of stress-induced senescence.
2024-09-01 | GSE210140 | GEO
Project description:Ribosomal S6 kinase 1 regulates 'inflammaging' via the senescence secretome II.
| PRJNA904792 | ENA
Project description:Ribosomal S6 kinase 1 regulates 'inflammaging' via the senescence secretome III.
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Project description:Early senescence-induced immunosuppressive β-cell secretome prevents type 1 diabetes
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Project description:Ribosomal S6 kinase 1 regulates 'inflammaging' via the senescence secretome I.
| PRJNA904793 | ENA
Project description:Cellular senescence is a stable cell growth arrest that is implicated in tissue aging and cancer. Senescent cells are characterized by an upregulation of proinflammatory and immunosuppressive cytokines and chemokines, which is termed as senescence-associated secretory phenotype (SASP). NAD+ metabolism plays a critical role in both tissue aging and cancer. However, the role of NAD+ metabolism in regulating the SASP is not well understood. Here we show that nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the NAD+ salvage pathway, governs the strengths of proinflammatory SASP during senescence. In contrast to downregulation of NAMPT during replicative senescence, NAMPT is upregulated during oncogene-induced senescence. NAMPT selectively regulates proinflammatory, but not immunosuppressive, SASP. NAMPT is regulated by HMGA1 through a distal enhancer element during senescence. HMGA1/NAMPT/NAD+ signaling axis promotes proinflammatory SASP through enhancing glycolysis and mitochondria respiration. Mechanistically, HMGA1/NAMPT promotes proinflammatory SASP through NAD+-mediated suppression of AMPK kinase, which suppresses p53-mediated inhibition of p38MAPK to enhance NFb activity. SASP regulation by NAD+ metabolism is independent of senescence-associated cell growth arrest. An increase in NAD+ levels is sufficient to convert SASP from low to high levels during replicative senescence. Together, we conclude that NAD+ metabolism governs the strengths of proinflammatory SASP. Given the tumor promoting effects of proinflammatory SASP, our results suggest that anti-ageing dietary NAD+ augmentation should be administered with precision.
2019-03-14 | GSE111841 | GEO