Effect of SHP2 inhibition on hepatic stellate cell transcriptome.
Ontology highlight
ABSTRACT: Hepatic stellate cell autophagy inhibits extracellular vesicle release to attenuate liver fibrosis. Primary human hepatic stellate cells were treated with PDGF or PDGF + SHP2 inhibitor. RNA was purified and submitted for sequencing to Mayo Clinic Genomics Core. After applying the filters FDR>0.05, Log2(FC)>1 and RPKM>15, we ended up with nearly 300 genes differentially regulated between the two conditions. Ingenuity Pathway Analysis revealed that Ostheoarthritis was the first pathway to be differentially regulated. From this pathway, REDD1 (DDIT4 transcript), an mTOR inhibitor, was further explored, especially in the context of extracellular vesicle release.
Project description:We report the effect of TGFβ vs PDGF 2h treatment in hepatic stellate cells. We also report the effect of TGFβ treatment for 48h in human hepatic stellate cells.
Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone. Hepatic stellate cells were isolated from liver of beta-PDGFR-wild-type or knockout mice, and treated with beta-PDGF ligand or vehicle control.
Project description:Glycolysis in hepatic stellate cells coordinates fibrogenic extracellular vesicle release in a spatial manner to amplify liver fibrosis
Project description:Liver cirrhosis is a strong risk factor for the development of hepatocellular carcinoma (HCC), yet the mechanisms by which cirrhosis predisposes patients to tumorigenesis are not well understood. Transgenic mice expressing platelet-derived growth factor C (Pdgf-c) under the control of the albumin promoter provide a unique animal model that mimics the step-wise disease progression in humans from fibrosis to HCC. The livers of Pdgf-c Tg mice show evidence of liver injury, including inflammation, proliferation, fibrosis and steatosis, and as the mice age, angiogenesis and dysplasia. Eighty-five percent of these mice develop HCC spontaneously, and have reduced survival that is related to their liver pathology. Through measurement of protein, RNA, and histological markers, we provide evidence to support the hypothesis that changes in liver stromal cells play an essential role in tumorigenesis in this model. A paracrine signaling model is proposed where ectopic expression of Pdgf-c in hepatocytes results in activation of hepatic stellate cells, which subsequently activates endothelial and Kupffer cells. Activation of these non-parenchymal cells promotes the release of hepatocyte growth factors that, together with changes in extracellular matrix, lead to the formation of HCC. Pdgf-c Tg mice provide a useful pre-clinical model in which to test novel drugs for chronic liver disease and HCC that focus on blocking the processes that alter the liver's fibrotic microenvironment. Two strains of mice, C57BL/6 and C57/BL6 Pdgf-c transgenic, were analyzed to see if liver stromal cells play an essential role in tumorigenesis.
Project description:Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs) and the release of fibrogenic nano-sized extracellular vesicles (EVs). Activated HSCs increase their glucose metabolism via glycolysis to satisfy high energy demands. Nevertheless, the mechanism of how glycolysis in HSCs coordinates fibrosis amplification in the fibrogenic zones in the liver is elusive and is the scope of this study. Single cell RNA sequencing (scRNAseq) and bulk RNAseq demonstrated that several glycolysis enzymes, including hexokinase 2 (HK2), were upregulated in activated HSCs. HSC-selective glycolysis-deficient mice (HK2ΔHSC) showed abrogated CCl4-mediated fibrosis as compared to littermate controls (HK2fl/fl). Spatial transcriptomics revealed an upregulation of several EV-related pathways in the fibrotic pericentral zone during liver fibrosis in control HK2fl/fl mice. However, glycolysis-deficient HK2ΔHSC mice showed downregulation of these EV-related pathways in the pericentral zone. Consistently, induction of glycolysis in HSCs in vitro, either by glucose or platelet-derived growth factor B (PDGF), upregulated the expression of several extracellular vesicle (EV)-related genes, including RAB31. Glycolysis in HSCs epigenetically enhanced RAB31 expression through histone-3 lysine-9 acetylation (H3K9ac) on the promoter region, leading to increased EV release. Functionally, glycolysis-dependent EVs were enriched with fibrogenic molecules and increased the expression of fibrotic markers in recipient HSCs. Finally, EVs derived from glycolysis-deficient HK2ΔHSC mice abrogated liver fibrosis amplification as compared to EVs derived from littermate control HK2fl/fl mice. In summary, glycolysis in HSCs amplifies liver fibrosis by promoting fibrogenic EV release in the pericentral fibrotic regions in the liver.
Project description:Liver cirrhosis is a strong risk factor for the development of hepatocellular carcinoma (HCC), yet the mechanisms by which cirrhosis predisposes patients to tumorigenesis are not well understood. Transgenic mice expressing platelet-derived growth factor C (Pdgf-c) under the control of the albumin promoter provide a unique animal model that mimics the step-wise disease progression in humans from fibrosis to HCC. The livers of Pdgf-c Tg mice show evidence of liver injury, including inflammation, proliferation, fibrosis and steatosis, and as the mice age, angiogenesis and dysplasia. Eighty-five percent of these mice develop HCC spontaneously, and have reduced survival that is related to their liver pathology. Through measurement of protein, RNA, and histological markers, we provide evidence to support the hypothesis that changes in liver stromal cells play an essential role in tumorigenesis in this model. A paracrine signaling model is proposed where ectopic expression of Pdgf-c in hepatocytes results in activation of hepatic stellate cells, which subsequently activates endothelial and Kupffer cells. Activation of these non-parenchymal cells promotes the release of hepatocyte growth factors that, together with changes in extracellular matrix, lead to the formation of HCC. Pdgf-c Tg mice provide a useful pre-clinical model in which to test novel drugs for chronic liver disease and HCC that focus on blocking the processes that alter the liver's fibrotic microenvironment.
Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone.
Project description:Analysis of hepatic stellate cells (HSCs) isoltaed from ASMA-HAS2 transgenic and HSC-specific Has2 knockout mice. HAS2 synthesized hyaluronic acid, one of major extracellular matrix. Results provide insight into the role of HAS2 in hepatic stellate cells.