ABSTRACT: DNA demethylation is regulated by the TET family proteins, whose enzymatic activity requires 2-oxoglutarate (2-OG) and iron that both are elevated in MASLD. We aimed to investigate liver TET1 in MASLD progression. Depleting TET1 substantially alleviated MASLD progression. Whole body Knockout of TET1 (TKO) slightly improved diet induced obesity and glucose homeostasis. Intriguingly, hepatic cholesterols, triglycerides, were significantly decreased upon TET1 depletion. Moreover, targeting TET1 with a small molecule inhibitor significantly suppressed MASLD progression. Liver TET1 plays a deleterious role in MASLD, suggesting the potential of targeting TET1 in hepatocytes to suppress MASLD.
Project description:The molecular mechanisms underlying the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) remain largely unclear. Emerging evidence suggests that microRNAs (miRNAs) play a critical role in transcriptional regulation by targeting genes involved in MASLD and other metabolic disorders, this study aims to elucidate the role of miR-93 in lipid metabolism and its impact on MASLD progression.
Project description:Senescent hepatocytes accumulate in metabolic dysfunction-associated steatotic liver disease (MASLD) and are linked to worse clinical outcomes. However, their heterogeneity and lack of specific markers have made them difficult to target therapeutically. Here, we define a senescent hepatocyte gene signature (SHGS) using in vitro and in vivo models and show that it tracks with MASLD progression/regression across mouse models and large human cohorts. Single-nucleus RNA-sequencing and functional studies reveal that SHGS+ hepatocytes originate from p21+ cells, lose key liver functions and release factors that drive disease progression. One such factor, GDF15, increases in circulation alongside SHGS+ burden and disease progression. Through chemical screening, we identify senolytics that selectively eliminate SHGS+ hepatocytes and improve MASLD in mice. Notably, SHGS enrichment also correlates with dysfunction in other organs. These findings establish SHGS+ hepatocytes as key drivers of MASLD and highlight a potential therapeutic strategy for targeting senescent cells in liver disease and beyond.
Project description:Analyze human biopsies for the investigation of metabolic dysfunction-associated steatotic liver disease (MASLD). We also analyzed plasma samples for biomarker discovery. And analyzed the role of the impact of the adipose tissue on plasma proteins in relation to MASLD
Project description:Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent hepatic disorder worldwide and closely associated with type 2 diabetes mellitus (T2DM). The pathogenesis of MASLD is multifaceted and its treatment options are very limited. Consequently, it is urgent to identify novel therapeutic targets and develop effective treatment strategies. RNA sequencing analysis was performed to understand the transcriptomic changes in a mouse model of MASLD.
Project description:Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is a growing epidemic with an estimated prevalence of 20‑30% in Europe and the most common cause of chronic liver disease worldwide. The onset and progression of MASLD are orchestrated by an interplay of the metabolic environment with genetic and epigenetic factors. Emerging evidence suggests altered DNA methylation pattern as a major determinant of MASLD pathogenesis coinciding with progressive DNA hypermethylation and gene silencing of the liver‑specific nuclear receptor PPARα, a key regulator of lipid metabolism. To investigate how PPARα loss of function contributes to epigenetic dysregulation in MASLD pathology, we studied DNA methylation changes in liver biopsies of WT and hepatocyte‑specific PPARα KO mice, following a 6‑week CDAHFD (choline-deficient, L-amino acid-defined, high-fat diet) or chow diet. Interestingly, genetic loss of PPARα function in hepatocyte‑specific KO mice could be phenocopied by a 6-week CDAHFD diet in WT mice which promotes epigenetic silencing of PPARα function via DNA hypermethylation, similar to MASLD pathology. Remarkably, genetic and lipid diet‑induced loss of PPARα function triggers compensatory activation of multiple lipid sensing transcription factors and epigenetic writer-eraser-reader proteins, which promotes the epigenetic transition from lipid metabolic stress towards ferroptosis and pyroptosis lipid hepatoxicity pathways associated with advanced MASLD. In conclusion, we show that PPARα function is essential to support lipid homeostasis and to suppress the epigenetic progression of ferroptosis‑pyroptosis lipid damage associated pathways towards MASLD fibrosis.
Project description:Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is a growing epidemic with an estimated prevalence of 20‑30% in Europe and the most common cause of chronic liver disease worldwide. The onset and progression of MASLD are orchestrated by an interplay of the metabolic environment with genetic and epigenetic factors. Emerging evidence suggests altered DNA methylation pattern as a major determinant of MASLD pathogenesis coinciding with progressive DNA hypermethylation and gene silencing of the liver‑specific nuclear receptor PPARα, a key regulator of lipid metabolism. To investigate how PPARα loss of function contributes to epigenetic dysregulation in MASLD pathology, we studied transcriptome profile changes that could induce changes in DNA methylation in liver biopsies of WT and hepatocyte‑specific PPARα KO mice, following a 6‑week CDAHFD (choline-deficient, L-amino acid-defined, high-fat diet) or chow diet. Interestingly, genetic loss of PPARα function in hepatocyte‑specific KO mice could be phenocopied by a 6-week CDAHFD diet in WT mice which promotes epigenetic silencing of PPARα function via DNA hypermethylation, similar to MASLD pathology. Remarkably, genetic and lipid diet‑induced loss of PPARα function triggers compensatory transcription of multiple lipid sensing transcription factors and epigenetic writer-eraser-reader proteins, which promotes the epigenetic transition from lipid metabolic stress towards ferroptosis and pyroptosis lipid hepatoxicity pathways associated with advanced MASLD. In conclusion, we show that PPARα function is essential to support lipid homeostasis and to suppress the epigenetic progression of ferroptosis‑pyroptosis lipid damage associated pathways towards MASLD fibrosis.
Project description:Aging increases the risk for failure of many metabolically-stressed organs and exacerbates liver degeneration related to obesity and diabetes. We used snRNA-seq to identify the effect of metabolic disease (MASLD) on biological aging of hepatocyte.
Project description:As metabolic dysfunction-associated steatotic liver disease (MASLD) frequently co_x0002_occurs in patients with chronic hepatitis B (CHB), the interplay between these two common liver conditions remains largely unexplored. A recent study suggest that MASH comorbidity can reduce intrahepatic interferon pathway activity and macrophage gene signatures in HBeAg_x0002_negative chronic HBV (ENEG) patients, potentially contributing to persistent infection and fibrosis. However, it remains unclear whether this phenomenon also occurs in MASLD with CHB patients.
Project description:The N6-methyladenosine (m6A) mRNA modification and the mitochondrial respiratory chain (MRC) hold paramount importance in the advancement of MASLD. This study thoroughly investigates the relationship and impact of m6A mRNA modification and mitochondrial function in the progression of MASLD. Here we report that the mRNA and protein levels of mitochondrial respiratory chain (MRC) subunits showed inconsistent trends in vivo experiments. Abnormal m6A modification and mitochondrial dysfunction in MASLD were attributed to the upregulation of methyltransferase like 3 (Mettl3) and the downregulation of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) induced by high-fat foods. Mettl3 promoted the MRC's function. However, knockout of the reader protein YTHDF1, which plays a crucial role in the m6A modification process, counteracted the effect of Mettl3 and suppressed MRC. In MASLD, damage to the MRC may be regulated by the Mettl3-m6A-YTHDF1 complex axis, especially by the role of YTHDF1. Our research has offered a novel perspective on the involvement of m6A mRNA methylation in the pathogenesis of MASLD.