Targeting senescent hepatocytes using the THBD-PAR1 inhibitor Vorapaxar ameliorates NAFLD progression.
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PROVIDER: PRJNA842690 | ENA |
REPOSITORIES: ENA
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Project description:Background: Senescent hepatocytes accumulate in parallel with fibrosis progression during NASH. The mechanisms that enable progressive expansion of nonreplicating cell populations and the significance of that process in determining NASH outcomes are unclear. Many types of senescing cells upregulate the THBD-PAR-1 signaling axis to remain viable. Vorapaxar, an FDA-approved PAR-1 inhibitor, blocks the activity of that pathway. We used vorapaxar to determine if and how THBD-PAR1 signaling promotes fibrosis progression in NASH. Methods: We evaluated the THBD-PAR1 pathway in liver biopsies from NAFLD patient cohorts with a spectrum of liver fibrosis. Chow fed mice were treated with viral vectors to over-express p16 specifically in hepatocytes and induce replicative senescence. Effects on the THBD-PAR-1 axis and regenerative capacity were assessed; the transcriptome of p16 over-expressing hepatocytes was characterized and we examined how conditioned medium from senescent but viable (dubbed ‘undead’) hepatocytes reprograms hepatic stellate cells. A genetically obese mouse model of NASH with little liver fibrosis, and a diet-induced mouse model of NASH with advanced fibrosis were treated with vorapaxar to determine effects on hepatocyte senescence and liver damage. Results: Inducing senescence up-regulates the THBD-PAR1 signaling axis in hepatocytes and induces their expression of fibrogenic factors, including hedgehog ligands. Hepatocyte THBD-PAR1 signaling increases in NAFLD and supports sustained hepatocyte senescence that limits effective liver regeneration and promotes maladaptive repair. Inhibiting PAR-1 signaling with vorapaxar interrupts this process, reduces the burden of ‘undead’ senescent cells, and safely improves NASH and fibrosis despite ongoing lipotoxic stress Conclusion: The THBD-PAR1 signaling axis is a novel therapeutic target for NASH because blocking this pathway prevents accumulation of senescing but viable hepatocytes that generate factors that promote maladaptive liver repair.
2023-03-01 | GSE204901 | GEO
Project description:Objective：Phospholipase D1 (PLD1), a phosphatidylcholine-hydrolyzing enzyme, has been found to be involved in cellular lipid metabolism. However, how PLD1 involves in hepatocyte lipid metabolism and thus affects non-alcoholic fatty liver diseases (NAFLD) has not been explicitly explored. Method: NAFLD is induced in hepatocyte-specific Pld1 knockout (Pld1(H)-KO) mice or control (Pld1-Flox) mice with a high fat diet (HFD) for 20 weeks. Plasma glucose and lipid levels, liver lipid and function parameters and inflammation- and fibrogenesis-related gene expression levels were studied. Changes in lipid composition of liver were detected by lipidomic analyses. Changes in gene expression profile were detected by mRNA sequencing. In vitro, alpha mouse liver 12 (AML12) cells were incubated with sodium palmitate (SP) to explore the mechanisms of PLD1 on development of NAFLD. The protein levels of PLD1 and CD36 were detected in the liver tissues of NAFLD patients. Finally, the therapeutic effect of NAFLD by inhibiting PLD with 5-Fluoro-2-indolyl deschlorohalopemide (FIPI) was examined. Results: PLD1 expression levels were increased in the liver tissues of NAFLD patients and the hepatocytes of HFD-induced mice. Compared with Pld1-Flox mice, Pld1(H)-KO mice exhibited lower plasma glucose and lipids levels, and decreased lipid accumulation, inflammation and fibrosis related gene expression levels in the liver tissues after HFD feeding. Inhibition of hepatocyte PLD1 significantly altered lipid composition, especially phosphatidic acids (PA) and lyso-PAs (LPA) levels in the liver tissues after NAFLD. Transcriptomic analysis showed that hepatocyte specific deficiency of PLD1 mainly decreased CD36 expression levels in the NAFLD liver tissues, which was confirmed at the protein and gene expression levels. In vitro, inhibition of PLD1 markedly decreased CD36 expression and lipid accumulation in SP treated AML12 cells. Furthermore, PA, the downstream product catalyzed by PLD1, increased the expression levels of CD36 and lipid accumulation in vitro, which was reversed by PPARγ antagonist. These suggested that PPARγ played an important role in transcriptional regulation of CD36 expression after PA stimulation. Finally, PLD inhibitor FIPI had significant therapeutic effect on HFD-induced NAFLD. Conclusion: Hepatocyte-specific deficiency of PLD1 ameliorates lipid accumulation and NAFLD development by inhibiting PPARγ/CD36 pathway conducted by PA.
2023-08-01 | GSE207281 | GEO
Project description:Inhibition of phospholipase D1 ameliorates NAFLD by reducing PPARγ/CD36 pathway mediated lipid accumulation in hepatocytes
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Project description:Effect of GCN5 depletion in hepatocytes in NAFLD
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Project description:Cysteine dioxygenase type 1 (Cdo1) is a key enzyme for cysteine catabolism that is enriched in liver, whose role in NAFLD remains poorly understood. Here, we show that exercise induces the expression of hepatic Cdo1 via the cAMP/PKA/CREB signaling pathway. Hepatocyte-specific knockout of Cdo1 (Cdo1LKO) impairs the effect of exercise against NAFLD, whereas hepatocyte-specific overexpression of Cdo1 (Cdo1LTG) and exercise synergistically ameliorates NAFLD in male mice. Mechanistically, Cdo1 facilitates the binding between AMPK and kinase active Camkk2, which activates AMPK signaling. This promotes fatty acid oxidation and mitochondrial biogenesis in hepatocytes to attenuate hepatosteatosis. Therefore, by promoting hepatic Camkk2-AMPK signaling pathway, Cdo1 acts as an important downstream effector of exercise to combat against NAFLD
2023-08-07 | GSE239729 | GEO
Project description:Effect of miR-33 supression in hepatocytes in NAFLD
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Project description:Transcription profiling of wild type and transgenic 35S:PAR1-GG seedlings. To characterize the transcriptional networks altered by constitutive overexpression of PAR1 in seedlings, using two-color long-oligonucleotide microarrays.
2007-11-03 | E-ATMX-29 | biostudies-arrayexpress
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:Objective: Thrombin is the key serine protease of the coagulation cascade and mediates cellular responses by activation of protease-activated receptors (PARs). The predominant thrombin receptor is PAR1 and in endothelial cells (ECs) thrombin dynamically regulates a plethora of phosphorylation events. However, it has remained unclear if thrombin signaling is exclusively mediated through PAR1. Furthermore, mechanistic insight into activation and inhibition of PAR1-mediated EC signaling is lacking. In addition, signaling networks of biased PAR1 activation after differential cleavage of the PAR1 N-terminus have remained an unresolved issue.Approach and Results: Here, we used a quantitative phosphoproteomics approach to show that ‘classical’ and ‘peptide’ activation of PAR1 induce highly similar signaling, that low thrombin concentrations initiate only limited phosphoregulation, and that the PAR1 inhibitors vorapaxar and parmodulin-2 demonstrate distinct antagonistic properties. Subsequent analysis of the thrombin-regulated phosphosites in presence of PAR1 inhibitors revealed that biased activation of PAR1 is not solely linked to a specific G-protein downstream of PAR1. In addition, we showed that only the canonical thrombin PAR1 tethered ligand induces extensive early phosphoregulation in ECs.Conclusions: Our study provides detailed insight in the signaling mechanisms downstream of PAR1. Our data demonstrates that thrombin-induced EC phosphoregulation is mediated exclusively through PAR1, that thrombin and thrombin-TL peptide induce similar phosphoregulation and that only canonical PAR1 cleavage by thrombin generates a tethered ligand that potently induces early signaling. Furthermore, platelet PAR1 inhibitors directly affect EC signaling, indicating it will be a challenge to design a PAR1 antagonist that will target only those pathways responsible for tissue pathology.
2017-08-22 | PXD004264 | Pride
Project description:Lung cancer is a fatal complication of idiopathic pulmonary fibrosis (IPF) with a poor prognosis. Current treatments are insufficient in improving the prognosis of lung cancer patients with comorbid idiopathic pulmonary fibrosis (IPF-LC). Senescent fibroblasts play a pivotal role within the tumor microenvironment, influencing tumor progression by secreted exosomes. With evidence that fibroblast senescence is an important mechanism of IPF, we sought to investigate the impact of senescent IPF lung fibroblast-derived exosomes on non-small cell lung cancer (NSCLC). Our results show that IPF fibroblasts (diseased human lung fibroblasts, DHLF) express significant senescence markers, promoting NSCLC proliferation, invasion, and epithelial-mesenchymal transition. Specifically, we observed senescent DHLFs secret more exosomes (DHLF-exosomes), which could enhance proliferation and colony-forming ability of cancer cells. Proteomic analysis of DHLF-exosomes identified upregulation of SASP factors, notably MMP1, which activates the surface receptor PAR1. Knocking down MMP1 or using PAR1 inhibitors reduced the tumor-promoting effects of DHLF-exosomes in vivo and in vitro. Mechanistically, MMP1 acted via activating the PI3K-AKT-mTOR pathway. In conclusion, our results suggest that exosomal MMP1 derived from senescent IPF fibroblasts promotes NSCLC proliferation and colony formation by targeting PAR1 and activating the PI3K-AKT-mTOR pathway. These findings provide a novel therapeutic approach for patients with IPF-LC.
2024-10-21 | GSE279637 | GEO