Similar Datasets
Project description:Liver injury causes “transdifferentiation” of quiescent hepatic stellate cells (Q-HSCs) into wound repairing myofibroblasts (MF-HSCs), whose uncontrolled activation leads ultimately to liver fibrosis. Although this process is triggered by deep metabolic and transcriptional reprogramming, functional links between these two key events are not yet understood. Here, using a compendium of in vitro, ex vivo and in vivo models of fibrogenic liver injuries in addition to human liver samples, we report that O-linked β D N acetylglucosaminylation (O GlcNAcylation), a post-translational modification (PTM) considered as nutritional sensor, is increased during myofibroblastic activation of HSCs and is required for their pro-fibrotic activities. Mechanistically, a multi omics approach combining proteomic, epigenomic and transcriptomic data mining revealed that O GlcNAcylation controls the transcriptional program of MF-HSCs by targeting the key fibrogenic transcription factors Basonuclin 2 (BNC2) and TEA domain transcription factor 4 (TEAD4) together with the Yes associated protein 1 (YAP1) co-activator. Indeed, inhibition of protein O GlcNAcylation impedes their stability leading to decreased functionality of the BNC2/TEAD4/YAP1 complex towards promoting activation of fibrogenic transcriptional regulatory elements. Altogether, this study unravels the fibrogenic role of protein O-GlcNAcylation identifying a vulnerable regulatory process in activated HSCs.
2024-05-21 | PXD045860 | Pride
Project description:Human LX-2 cells were used for TEAD4 ChIP-seq
2024-05-22 | GSE243104 | GEO
Project description:O-GlcNAcylation controls pro-fibrotic transcriptional regulatory signaling in hepatic stellate cells
| PRJNA1016361 | ENA
Project description:O-GlcNAcylation controls pro-fibrotic transcriptional regulatory signaling in hepatic stellate cells (HSCs)
| PRJNA1016371 | ENA
Project description:Our data describe autophagic flux in primary rat hepatic stellate cells (rHSCs) treated with pro-fibrotic growth factor, transforming growth factor beta (TGF-β). An autophagy flux experiment determines the rate of synthesis and degradation of the autophagosome marker, LC3-II in the presence and absence of the lysosomal inhibitor bafilomcyin, which blocks LC3-II degradation in lysosomes. The effects of a test agent on LC3-II flux through the autophagic pathway is determined immunochemically by its relative amounts detected in lysates of cells treated with and without bafilomycin. This measurement helps to validate whether exposure to an agent affects the biogenesis or the degradation of autophagosomes during autophagy, a major macromolecular degrading mechanism in eukaryotic cells. ("Rev-erb Agonist and TGF-β Similarly Affect Autophagy but Differentially Regulate Hepatic Stellate Cell Fibrogenic Phenotype" (Thomes et al., in press) [1].
| S-EPMC5156597 | biostudies-literature
Project description:Background/aimsExcessive consumption of dietary fat and sugar is associated with an elevated risk of nonalcoholic fatty liver disease (NAFLD). Hepatocytes exposed to saturated fat or sugar exert effects on nearby hepatic stellate cells (HSCs); however, the mechanisms by which this occurs are poorly understood. We sought to determine whether paracrine effects of hepatocytes exposed to palmitate and fructose produced profibrotic transcriptional responses in HSCs.MethodsWe performed expression profiling of mRNA and lncRNA from HSCs treated with conditioned media (CM) from human hepatocytes treated with palmitate (P), fructose (F), or both (PF).ResultsIn HSCs exposed to CM from palmitate-treated hepatocytes, we identified 374 mRNAs and 607 lncRNAs showing significant differential expression (log2 foldchange ≥ |1|; FDR ≤0.05) compared to control cells. In HSCs exposed to CM from PF-treated hepatocytes, the number of differentially expressed genes was much higher (1198 mRNAs and 3348 lncRNAs); however, CM from fructose-treated hepatocytes elicited no significant changes in gene expression. Pathway analysis of differentially expressed genes showed enrichment for hepatic fibrosis and hepatic stellate cell activation in P- (FDR =1.30E-04) and PF-(FDR =9.24E-06)
groups. We observed 71 lncRNA/nearby mRNA pairs showing differential expression under PF conditions. There were 90 mRNAs and 264 lncRNAs strongly correlated between the PF group and differentially expressed transcripts from a comparison of activated and quiescent HSCs, suggesting that some of the transcriptomic changes occurring in response to PF overlap with HSC activation.ConclusionThe results reported here have implications for dietary modifications in the prevention and treatment of NAFLD.
| S-EPMC8265013 | biostudies-literature
Project description:Liver fibrosis occurs in response to chronic liver injury and is characterized by an excessive deposition of extracellular matrix. Activated hepatic stellate cells are primarily responsible for this process. A possible strategy to counteract the development of hepatic fibrosis could be the reversion of the activated phenotype of hepatic stellate cells. Extracellular vesicles (EVs) are nanosized membrane vesicles involved in intercellular communication. Our previous studies have demonstrated that EVs derived from human liver stem cells (HLSCs), a multipotent population of adult stem cells of the liver with mesenchymal-like phenotype, exert in vivo anti-fibrotic activity in the liver. However, the mechanism of action of these EVs remains to be determined. We set up an in vitro model of hepatic fibrosis using a human hepatic stellate cell line (LX-2) activated by transforming growth factor-beta 1 (TGF-β1). Then, we investigated the effect of EVs obtained from HLSCs and from human bone marrow-derived mesenchymal stromal cells (MSCs) on activated LX-2. The incubation of activated LX-2 with HLSC-EVs reduced the expression level of alpha-smooth muscle actin (α-SMA). Conversely, MSC-derived EVs induced an increase in the expression of pro-fibrotic markers in activated LX-2. The analysis of the RNA cargo of HLSC-EVs revealed the presence of several miRNAs involved in the regulation of fibrosis and inflammation. Predictive target analysis indicated that several microRNAs (miRNAs) contained into HLSC-EVs could possibly target pro-fibrotic transcripts. In particular, we demonstrated that HLSC-EVs shuttled miR-146a-5p and that treatment with HLSC-EVs increased miR-146a-5p expression in LX-2. In conclusion, this study demonstrates that HLSC-EVs can attenuate the activated phenotype of hepatic stellate cells and that their biological effect may be mediated by the delivery of anti-fibrotic miRNAs, such as miR-146a-5p.
| S-EPMC8593217 | biostudies-literature
Project description:Liver fibrosis occurs in most cases of chronic liver disease, which are somewhat common, but also a potentially deadly group of diseases. In vitro modeling of liver fibrosis relies primarily on the isolation of in vivo activated hepatic stellate cells (aHSCs) and studying them in standard tissue culture dishes (two-dimensional [2D]). In contrast, modeling of fibrosis in a biofabricated three-dimensional (3D) construct allows us to study changes to the environment, such as extracellular matrix (ECM) composition and structure, and tissue rigidity. In the current study, we used aHSCs produced through subcultures in 2D and encapsulated them in a 3D collagen gel to form spherical constructs. In parallel, and as a comparison, we used an established HSC line, LX-2, representing early and less severe fibrosis. Compared with LX-2 cells, the aHSCs created a stiffer environment and expressed higher levels of TIMP1 and LOXL2, all of which are indicative of advanced liver fibrosis. Collectively, this study presents a fibrosis model that could be incorporated with multi-cellular models to more accurately reflect the effects of a severe fibrotic environment on liver function.
| S-EPMC7370813 | biostudies-literature
Project description:Non-alcoholic steatohepatitis (NASH) results, in part, from the interaction of metabolic derangements with predisposing genetic variants, leading to liver-related complications and mortality. The strongest genetic determinant is a highly prevalent missense variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3 p.I148M). In human liver hepatocytes PNPLA3 localizes to the surface of lipid droplets where the mutant form is believed to enhance lipid accumulation and release of pro-inflammatory cytokines. Less is known about the role of PNPLA3 in hepatic stellate cells (HSCs). Here we characterized HSC obtained from patients carrying the wild type (n = 8 C/C) and the heterozygous (n = 6, C/G) or homozygous (n = 6, G/G) PNPLA3 I148M and investigated the effect of genotype and PNPLA3 downregulation on baseline and TGF-β-stimulated fibrotic gene expression. HSCs from all genotypes showed comparable baseline levels of PNPLA3 and expression of the fibrotic genes α-SMA, COL1A1, TIMP1 and SMAD7. Treatment with TGF-β increased PNPLA3 expression in all 3 genotypes (~2-fold) and resulted in similar stimulation of the expression of several fibrogenic genes. In primary human HSCs carrying wild-type (WT) PNPLA3, siRNA treatment reduced PNPLA3 mRNA by 79% resulting in increased expression of α-SMA, Col1a1, TIMP1, and SMAD7 in cells stimulated with TGF-β. Similarly, knock-down of PNPLA3 in HSCs carrying either C/G or G/G genotypes resulted in potentiation of TGF-β induced expression of fibrotic genes. Knockdown of PNPLA3 did not impact fibrotic gene expression in the absence of TGF-β treatment. Together, these data indicate that the presence of the I148M PNPLA3 mutation in HSC has no effect on baseline activation and that downregulation of PNPLA3 exacerbates the fibrotic response irrespective of the genotype.
| S-EPMC8654208 | biostudies-literature
Project description:Activation of quiescent hepatic stellate cells (HSCs) into proliferative myofibroblasts drives extracellular cellular matrix (ECM) accumulation and liver fibrosis; nevertheless, transcriptional network that promotes such the process remains elusive. ZNF469, a putative C2H2 zinc finger protein, is found to be upregulated upon HSC activation; however, the molecular function of ZNF469 is completely unknown. Here, we show that knockdown of ZNF469 in primary human HSCs impaired proliferation, migration, and collagen production. Conversely, overexpression of ZNF469 in HSCs yielded the opposite results. TGFb promoted expression of ZNF469 in a Smad3-dependent manner where the binding of Smad3 was confirmed at the ZNF469 promoter. RNA-seq data of ZNF469-knockdown HSCs revealed the ECM-receptor interaction as the top affected pathway, and significant downregulation of various collagen and proteoglycan genes was observed. To explore the function of ZNF469, we cloned a full-length open reading frae (ORF) of ZNF469 with an epitope tag and identified a nuclear localization of the protein. ChIP assays revealed the presence of ZNF469 at the promoter of ECM genes, supporting its function as a transcription factor. Analysis of human fibrotic and cirrhotic tissues showed increased expression of ZNF469 and a positive correlation between expression levels of ZNF469 and ECM genes. Moreover, this observation was similar in other fibrotic organs, including heart, lung, and skin. Together, this study is the first to reveal the roles of ZNF469 as a pro-fibrotic factor in HSCs and suggests ZNF469 as a novel target for antifibrotic therapy.
2024-03-15 | GSE252958 | GEO