Project description:MAFLD is a heterogenous spectrum disorder affecting 20% of the population. Inflammatory processes contribute to various stages of MAFLD and thought to instigate hepatic fibrosis. For this reason, targeting inflammation has been heavily nominated as an approach to mitigating liver fibrosis. Lipopolysaccharide binding protein is a secreted protein that plays an established role in innate immune responses. In a murine model of MAFLD, we used a liver-specific deletion of LBP model to study its role in hepatic inflammation. Single nucleus RNA-seq were applied to investigate the role of LBP in hepatic cell composition.
Project description:The aim of this research is to reveal the cellular crosstalk in fibrosis liver using transgenic pigs (TG) expressing humanized risk genes (PNPLA3I148M-GIPRdn-hIAPP) as a MAFLD model. The study uses single-nucleus sequencing to reveal the differentiation and interaction characteristics of various cell populations in the liver during the development of MAFLD. Compared to wild-type pigs (WT), the model pigs showed significantly increased plasma levels of neurotensin and phosphatidylserine, along with insulin resistance and significantly decreased HDL-c levels. After 6 months of high-fat high-sucrose diet induction, the model pigs exhibited obvious liver pathological features, including fat deposition, inflammatory cell aggregation, fibrosis, and blocked insulin signaling pathways. Single-nucleusl transcriptome sequencing identified six main cell types in the liver, and correlation analysis showed similar liver cell clusters, zones, and functions between pigs and humans. Liver cells near the central vein and liver sinusoidal endothelial cells (LSECs) were sensitive to metabolic changes and exhibited impaired function and reduced numbers first. Fibrosis-related pathways and the Rap1 pathway were activated in hepatic stellate cells of the model pigs, while retinol metabolism decreased, and the number of activated hepatic stellate cells increased. The differentiation direction of macrophages in the model pig's liver was markedly different from that in the WT pigs; the former differentiated toward the M1 phenotype, showing high expression of MHC-II antigen presentation molecules, various cytokines, phagosomes, and lysosomal-related genes. In contrast, the macrophages in the WT pig's liver primarily differentiated toward the M2 phenotype and expressed genes related to immune regulation and injury repair. There was active cell interaction between hepatic stellate cells, endothelial cells, and M1-type macrophages, promoting the development of chronic inflammation and fibrosis through interactions of receptors such as FGFs-FGFRs, PDGFs-PDGFRs, EFNA1-EPHRs, and CXCL12-CXCR4/CXCR7.In conclusion, the transgenic pig model of MAFLD exhibits liver pathological features consistent with MAFLD patients. The receptor interactions between hepatic stellate cells, endothelial cells, and macrophages play a key role in regulating metabolic inflammation and fibrosis development. Remarkable changes in receptor interactions hold promise for application in MAFLD drug development.
Project description:Mitochondrial function is an important control variable in the progression of metabolic dysfunction associated fatty liver disease (MAFLD). We hypothesize that organization and function of mitochondrial electron transport chain (ETC) in this pathologic condition is a consequence of shifted substrate availability. Paradoxically, in MAFLD increased de novo lipogenesis (DNL) occurs despite hepatic insulin resistance. Therefore, we addressed this question using our animal model alb-SREBP-1c, which exhibits increased DNL by constitutively active SREBP-1c. Using an omics approach, we show that the abundance of ETC complex subunits and metabolic pathways are altered in liver of these animals. Analyses of cellular metabolic status by functional assays revealed that SREBP-1c-forced DNL induces a limitation of substrates for oxidative phosphorylation that is rescued by enhanced complex II activity. Furthermore, energy metabolism associated gene regulation indicates the counteracting to increase expression of mitochondrial genes and features cell communication by miRNA and exosomal RNA transfer. In conclusion, substrate availability fuels mainly complex II electron flows as a consequence of activated DNL with impact on whole body by liver-specific exosomal RNAs in early stages of MAFLD.
Project description:Metabolic-associated fatty liver disease (MAFLD) comprises a spectrum of clinical entries ranging from benign steatosis to cirrhosis. A key event in the pathophysiology of MAFLD is the development of non-alcoholic steatohepatitis (NASH) that may lead to fibrosis and hepatocellular carcinoma. What triggers inflammation in MAFLD is unknown. We find that lipid accumulation in hepatocytes induces expression of ligands for the activating immune receptor NKG2D. Tissue-resident innate-like T cells are activated through NKG2D and secrete IL-17A. IL-17A licenses hepatocytes to produce chemokines that recruit pro-inflammatory cells into the liver, causing NASH and fibrosis. NKG2D-deficient mice did not develop fibrosis in a dietary model for NASH and had a marked decrease in the incidence of hepatic tumors. Importantly, the frequency of IL-17A+ γδ T cells in the blood MAFLD patients correlated with liver pathology. Our findings identify a key molecular mechanism through which stressed hepatocytes trigger inflammation in context of MAFLD.
Project description:Understanding mechanisms causing MAFLD (Metabolic Associated Fatty Liver Disease) and its progression to MASH (metabolic dysfunction-associated steatohepatitis) is clinically important and scientifically challenging. Hepatic insulin resistance is a common component in the progression of MAFLD in patients and experimental animals; however, hepatic steatosis caused by the HFD45% (high-fat diet) decreases during chronic hepatic IR generated by inactivation of Irs1/2 (LDKO), AKT1/2, or InsR 1-3—which is inconsistent with the expected relationship between IR and MAFLD in humans4. Here we found that complete hepatic insulin resistance promotes the fructose-enriched GAN diet-induced MAFLD, including acute inflammation and MASH in LDKO mice. Unexpectedly, fructose phosphorylation catalyzed by hepatic Khk (ketohexokinase) was not required as acute MAFLD progressed strongly in LDKOKhkL/L mice fed the GAN diet. FoxO1 activated during hepatic IR induces Fst (Follistatin) expression and secretion from the liver of LDKO mice. Inactivation of hepatic FoxO1 in LTKO mice (LDKO•FoxO1L/L) or Fst in LDKOFstKO mice prevented acute MAFLD during the GAN diet. Consistently, overexpression of hepatic Fst promoted GAN diet-induced MAFLD/MASH and hepatic carcinoma. Mechanistically, circulating Fst promoted adipose tissue IR and lipolysis, which can deliver FFA (free fatty acid) to the liver for esterification with excess Gro3P (glycerol 3-phosphate) generated by fructose metabolism, although hepatic DNL (de novo lipogenesis) decreased strongly in LDKO mice while. Since circulating FST correlates positively with both T2D and MAFLD in humans, our results suggests that hepatic FST induced by progressive hepatic IR might promote MAFLD/MASH during the consumption of sugar-sweetened food and beverages consumed frequently by people and animals with T2D.
Project description:Mitochondrial function is an important control variable in the progression of metabolic dysfunction associated fatty liver disease (MAFLD). We hypothesize that organization and function of mitochondrial electron transport chain (ETC) in this pathologic condition is a consequence of shifted substrate availability. Paradoxically, in MAFLD increased de novo lipogenesis (DNL) occurs despite hepatic insulin resistance. Therefore, we addressed this question using our animal model alb-SREBP-1c, which exhibits increased DNL by constitutively active SREBP-1c. Using an omics approach, we show that the abundance of ETC complex subunits and metabolic pathways are altered in liver of these animals. Analyses of cellular metabolic status by functional assays revealed that SREBP-1c-forced DNL induces a limitation of substrates for oxidative phosphorylation that is rescued by enhanced complex II activity. Furthermore, energy metabolism associated gene regulation indicates the counteracting to increase expression of mitochondrial genes and features cell communication by miRNA and exosomal RNA transfer. In conclusion, substrate availability fuels mainly complex II electron flows as a consequence of activated DNL with impact on whole body by liver-specific exosomal RNAs in early stages of MAFLD.https://pubmed.ncbi.nlm.nih.gov/35743314/
Project description:Mitochondrial function is an important control variable in the progression of metabolic dysfunction associated fatty liver disease (MAFLD). We hypothesize that organization and function of mitochondrial electron transport chain (ETC) in this pathologic condition is a consequence of shifted substrate availability. Paradoxically, in MAFLD increased de novo lipogenesis (DNL) occurs despite hepatic insulin resistance. Therefore, we addressed this question using our animal model alb-SREBP-1c, which exhibits increased DNL by constitutively active SREBP-1c. Using an omics approach, we show that the abundance of ETC complex subunits and metabolic pathways are altered in liver of these animals. Analyses of cellular metabolic status by functional assays revealed that SREBP-1c-forced DNL induces a limitation of substrates for oxidative phosphorylation that is rescued by enhanced complex II activity. Furthermore, energy metabolism associated gene regulation indicates the counteracting to increase expression of mitochondrial genes and features cell communication by miRNA and exosomal RNA transfer. In conclusion, substrate availability fuels mainly complex II electron flows as a consequence of activated DNL with impact on whole body by liver-specific exosomal RNAs in early stages of MAFLD.https://pubmed.ncbi.nlm.nih.gov/35743314/
Project description:A differential label-fee proteomics approach was performed using 27 biopsies from patients with HCV-associated hepatic fibrosis. For statistical analysis the patients were grouped into a low and a high fibrosis group. The low fibrosis group contained 13 patients of fibrosis stages 0, 1 and 2, whereas the high fibrosis group contained 14 patients of fibrosis stages 3 and 4 (fibrosis stages according to Batts-Ludwig classification).
Project description:Transcriptomic analysis was applied to liver tissues of seven patients with MAFLD and nine normal controls,then, differential genes were identified by comparative analysis of sequencing results, and target genes that may be related to the pathogenesis of MAFLD were further studied.This study may provide new ideas for understanding the pathogenesis of MAFLD and thus provide new targets for the treatment of MAFLD.
Project description:Aim: Hepatic fibrosis is a major worldwide medical problem and can develop into liver cirrhosis and hepatocellular carcinoma(HCC). Until now, there are no effective drugs for liver ?brosis because the molecular mechanism of progression of liver fibrosis is not fully understood. MicroRNAs (miRNAs) are an important class of small non-coding functional RNAs that play a key role in many biological processes. The purpose of this study was to clarify how the aberrant expression of miRNAs participates in development of the liver fibrosis in rat liver fibrosis model. Methods: Fibrotic and paired normal liver tissues were collected and assesssed by deep sequencing technology. MiRNA pro?ling results were validated by quantitative real-time polymerase chain reaction (qRT-PCR) and bioinformatics was used to predict miRNA targets. Results: Nine deregulated miRNAs were induced in porcine serum (PS)-induced hepatic fibrosis versus normal liver. Further analysis revealed several signaling pathways (e.g., gap junction and neuroactive ligand-receptor interaction) may be associated with hepatic fibrogenesis. Conclusion: Several miRNAs are dysregulated in PS-induced hepatic fibrosis and seem to be closely associated with hepatic fibrogenesis. These results provide an experimental basis for understanding the mechanism of hepatic fibrosis. We sequenced two samples, including case and control. Each sample has two replicates.