Project description:Non-alcoholic fatty liver disease (NAFLD) is characterized by a series of pathological changes that can progress from simple fatty liver disease to non-alcoholic steatohepatitis (NASH). The objective of this study is to describe changes in global gene expression associated with the progression of NAFLD. This study is focused on the expression levels of genes responsible for the absorption, distribution, metabolism and excretion (ADME) of drugs. Differential gene expression between three clinically defined pathological groups; normal, steatosis and NASH was analyzed. The samples were diagnosed as normal, steatotic, NASH with fatty liver (NASH fatty) and NASH without fatty liver (NASH NF). Genome-wide mRNA levels in samples of human liver tissue were assayed with Affymetrix GeneChipM-. Human 1.0ST arrays
Project description:Recombinant cytokines have limited anti-cancer efficacy mostly due to narrow therapeutic window and systemic adverse effects. IL-18 is an inflammasome induced proinflammatory cytokine that enhances T and NK cell activity and stimulates IFNg production. The activity of IL-18 is naturally blocked by a high affinity endogenous binding protein (IL-18BP). IL-18BP is induced in the tumor microenvironment (TME) in response to IFNg upregulation in a negative feedback mechanism. In this study we found that IL-18 is upregulated in the TME compared to the periphery across multiple human tumors and most of it is bound to IL-18BP. Bound IL-18 levels were largely above the amount required for T cell activation in vitro, implying that releasing IL-18 in the TME could lead to potent T cell immune activation. To restore the activity of endogenous IL-18 we generated COM503, a high affinity anti-IL-18BP antibody (Ab), that blocks the IL-18BP:IL-18 interaction and displaces pre-complexed IL-18 to enhance T cell and NK cell activation. In vivo, administration of a surrogate anti-IL-18BP Ab, either alone or in combination with anti-PD-L1 Ab, resulted in significant tumor growth inhibition and increased survival across multiple mouse tumor models. Moreover, anti-IL-18BP Ab induced pronounced TME-localized immune modulation including an increase in polyfunctional non-exhausted T and NK cell numbers and activation. In contrast, no increase in inflammatory cytokines and lymphocyte numbers or activation state was observed in serum and spleen. Taken together, blocking IL-18BP using an Ab is a promising novel approach to harness cytokine biology for the treatment of cancer.
Project description:Non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is a significant risk factor for hepatocellular carcinoma (HCC). However, a preclinical model of progressive NAFLD/NASH is largely lacking. Here, we report that mice with hepatocyte-specific deletion of Tid1, encoding a mitochondrial cochaperone, tended to develop NASH-dependent HCC. Mice with hepatic Tid1 deficiency showed impairing mitochondrial function and causing fatty acid metabolic dysregulation; meanwhile, sequentially developed fatty liver, NASH, and cirrhosis/HCC in a diethylnitrosamine (DEN) induced oxidative environment. The pathological signatures of human NASH, including cholesterol accumulation and activation of inflammatory and apoptotic signaling pathways, are also present in these mice. Clinically, low Tid1 expression was associated with unfavorable prognosis in patients with HCC. Empirically, hepatic Tid1 deficiency directly disrupts entire mitochondria that play a key role in the NASH-dependent HCC development. Overall, we established a new mouse model that develops NASH-dependent HCC and provides a promising approach to improve the treatment.
Project description:NASH is characterized by hepatic steatosis, inflammation, fibrosis and liver damage, which eventually results in liver dysfunction due to cirrhosis or hepatocellular carcinoma. However, the cellular and molecular mechanisms underlying NASH progression remain largely unknown. In this study, we aimed to elucidate the impact of Nr4a family in CD4 T cells in NASH development.
Project description:Limb expression 1-like protein (LIX1L) plays important role in various liver disorders, but its role and underlying mechanism in nonalcoholic hepatitis (NASH) and HCC progression remains obscure. Here, we report that LIX1L functions as a key integrative regulator linking lipid metabolism and inflammation, adipose tissue dysfunction and hepatic microenvironment reprogramming which promotes NASH progression. LIX1L significantly upregulated in NAFLD/NASH patients, mouse models and palmitic acid-stimulated hepatocytes. Lix1l deletion inhibits lipid deposition, inflammatory response and fibrosis in liver as well as adipocyte differentiation by downregulation of fatty acid translocase CD36 expression, alleviating NASH and associated HCC progression. In contrast, adeno-associated virus (AAV)-mediated LIX1L overexpression exacerbates NASH progression in mice. Mechanistically, metabolic stress promotes PARP1 mediated poly-ADP-ribosylation (PARylation) of LIX1L, subsequently increasing the stability and RNA binding ability of LIX1L protein. LIX1L binds to AU-rich element (ARE) in the 3’ untranslated region (UTR) of CD36 mRNA, thus attenuating CD36 mRNA decay. In NASH and associated HCC mouse models, LIX1L deficiency-mediated downregulation of CD36 suppresses adipogenesis, hepatic lipid uptake, and reprograms the tumor-prone liver microenvironment with increased cytotoxic T lymphocytes (CTLs), reduced immunosuppressive cell proportions. These data indicate a systematic function of LIX1L in the pathogenesis of NASH and underscore the PARP1/LIX1L/CD36 axis as a potential target for treatment of NASH and associated HCC.
Project description:Mitochondrial calcium signaling plays a critical role in mitochondrial homeostasis during non-alcoholic steatohepatitis (NASH) progression. Here, we report Ras‐GTPase activating protein SH3 domain‐binding protein 1 (G3BP1), a core protein of stress granule (SG), significantly upregulated in NAFLD/NASH patients, mouse models and palmitic acid-stimulated hepatocytes. Hepatocyte-specific G3BP1 deficiency attenuates NASH in two dietary mouse models. SG and the mitochondrial import protein TOM70 collaboratively mediate the translocation of G3BP1 to the mitochondria. G3BP1 interacts and stabilizes mitochondrial calcium uptake 1 (MICU1) via inhibiting YME1L1-mediated degradation of MICU1, and also impedes MCU complex activity and assembly, leading to mitochondrial calcium overload. Moreover, metabolic stress suppresses TRIM25-mediated K63-ubiquitination of G3BP1 and subsequent SG disassembly. Pharmacological inhibition of G3BP1 impairs the G3BP1-MICU1 interaction and prevents mitochondrial homeostasis imbalance and NASH progression. Collectively, we uncover the significant role of mitochondrial G3BP1 in mitochondrial homeostasis and NASH progression, which provides a potential target for therapeutic interventions.
Project description:NASH is characterized by hepatic steatosis, inflammation, fibrosis and liver damage, which eventually results in liver dysfunction due to cirrhosis or hepatocellular carcinoma. However, the cellular and molecular mechanisms underlying NASH progression remain largely unknown. In this study, we aimed to elucidate the impact of Nr4a family in CD4 T cells in NASH development.
Project description:Non-alcoholic steatohepatitis (NASH) is a global health concern without treatment. The challenge in finding effective therapies is due to the lack of good mouse models and the complexity of the disease, characterized by gene–environment interactions. We tested the susceptibility of seven mouse strains to develop NASH. The severity of the clinical phenotypes observed varied widely across strains. PWK/PhJ mice were the most prone to develop hepatic inflammation and the only strain to progress to NASH with extensive fibrosis, while CAST/EiJ mice were completely resistant. Levels of mitochondrial transcripts and proteins as well as mitochondrial function were robustly reduced specifically in the liver of PWK/PhJ mice, suggesting a central role of mitochondrial dysfunction in NASH progression. Importantly, the NASH gene expression profile of PWK/PhJ mice had the highest overlap with the human NASH signature. Our study exposes the limitations of using a single mouse genetic background in metabolic studies and describes a novel NASH mouse model with features of the human NASH.
Project description:Patients with non-alcoholic fatty liver disease (NAFLD), especially advanced non-alcoholic steatohepatitis (NASH), have an increased risk of cardiovascular diseases (CVD) due to the production of pro-inflammatory factors, vasoactive and thrombogenic molecules, or insulin resistance and related disorders. While elevated risk and incidence of CVD events in NAFLD/NASH are well established, whether such events will, in turn, influence the pathogenesis of NAFLD remains unknown. Here, we show that myocardial infarction (MI) accelerates the linear hepatic pathological progression of NAFLD. In humans, NAFLD patients who experienced CVD events after their diagnosis of NAFLD show a rapid progression of hepatic fibrosis. In mouse models of NASH, MI promotes hepatic fibrosis, accompanied by elevated circulating Ly6Chi monocytes and their recruitment to the damaged liver tissues. Depleting these cells abrogate MI-induced hepatic pathological effects in mice with NASH. Meanwhile, MI substantially elevates circulating and cardiac periostin contents, which act on hepatocytes and stellate cells to promote hepatic lipid accumulation and fibrosis, finally exacerbating hepatic pathological progression of NASH. Additionally, specific silence of cardiac periostin markedly attenuates MI-induced hepatic pathological progression of mice with NASH. These preclinical and clinical results demonstrate that MI alternates systemic homeostasis and upregulates the production of pro-fibrotic factors, triggering cross-disease communication that accelerates hepatic pathological progression of NAFLD.
Project description:Nonalcoholic steatohepatitis (NASH), characterized by hepatic steatosis, inflammation, and liver injury, has become a leading cause of end-stage liver diseases and liver transplantation. Krüppel-like factors 10 (KLF10) is a Cys2/His2 zinc finger transcription factor that regulates cell growth, apoptosis, and differentiation. However, whether it plays a role in the development and progression of chronic liver diseases like NASH remains poorly understood. In the present study, we found that KLF10 expression was selectively upregulated in the mouse models and human patients with NASH, compared with simple steatosis (NAFL). Gain- and loss-of function studies demonstrated that hepatocyte-specific overexpression of KLF10 aggravated, whereas its depletion alleviated diet-induced NASH pathogenesis in mice. Mechanistically, transcriptomic analysis and subsequent functional experiments showed that KLF10 promotes hepatic lipid accumulation and inflammation through the palmitoylation and plasma membrane localization of fatty acid translocase CD36 via transcriptionally activation of zDHHC7. Indeed, both expression of zDHHC7 and palmitoylation of CD36 are required for the pathogenic roles of KLF10 in NASH progression. Thus, our results identify an important role for KLF10 in NAFL-to-NASH development through zDHHC7-mediated CD36 palmitoylation.