Project description:OBJECTIVE: Nonalcoholic steatohepatitis (NASH) is closely associated with metabolic syndrome and increases the risk for end-stage liver disease, such as cirrhosis and hepatocellular carcinoma. Despite this, the molecular events that influence NASH pathogenesis remain poorly understood. The objectives of the current study are to delineate the transcriptomic and proteomic signatures of NASH liver, to identify potential pathogenic pathways and factors, and to critically assess their role in NASH pathogenesis. METHODS: We performed RNA sequencing and quantitative proteomic analyses on the livers from healthy and diet-induced NASH mice. We examined the association between plasma levels of TSK, a newly discovered hepatokine, and NASH pathologies and reversal in response to dietary switch in mice. Using TSK knockout mouse model, we determined how TSK deficiency modulates key aspects of NASH pathogenesis. RESULTS: RNA sequencing and quantitative proteomic analyses revealed that diet-induced NASH triggers concordant reprogramming of the liver transcriptome and proteome in mice. NASH pathogenesis is linked to elevated plasma levels of the hepatokine TSK, whereas dietary switch reverses NASH pathologies and reduces circulating TSK concentrations. Finally, TSK inactivation protects mice from diet-induced NASH and liver transcriptome remodeling. CONCLUSIONS: Global transcriptomic and proteomic profiling of healthy and NASH livers revealed the molecular signatures of diet-induced NASH and dysregulation of the liver secretome. Our study illustrates a novel pathogenic mechanism through which elevated TSK in circulation promotes NASH pathologies, thereby revealing a potential target for therapeutic intervention.
Project description:Non-alcoholic steatohepatitis (NASH) has emerged as a major challenge for public health because of high global prevalence and lack of evidence-based therapies. Most animal models of NASH lack sufficient validation regarding disease progression and pharmacological treatment. The Gubra-Amylin NASH (GAN) diet-induced obese (DIO) mouse demonstrate clinical translatability with respect to disease etiology and hallmarks of NASH. This study aimed to evaluate disease progression and responsiveness to clinically effective interventions in GAN DIO-NASH mice. Disease phenotyping was performed in male C57BL/6J mice fed the GAN diet high in fat, fructose and cholesterol for 28-88 weeks. GAN DIO-NASH mice with biopsy-confirmed NASH and fibrosis received low-caloric dietary intervention, semaglutide (30 nmol/kg/day, s.c.) or lanifibranor (30 mg/kg/day, p.o.) for 8 and 12 weeks, respectively. Within-subject change in NAFLD Activity Score (NAS) and fibrosis stage was evaluated using automated deep learning-based image analysis. GAN DIO-NASH mice showed clear and reproducible progression in NASH, fibrosis stage and tumor burden with high incidence of hepatocellular carcinoma. Consistent with clinical trial outcomes, semaglutide and lanifibranor improved NAS, while only lanifibranor induced regression in fibrosis stage. Dietary intervention also demonstrated substantial benefits on metabolic outcomes and liver histology. Differential therapeutic efficacy of dietary intervention, semaglutide and lanifibranor was supported by quantitative histology, RNA sequencing, and blood/liver biochemistry. In conclusion, the GAN DIO-NASH mouse model recapitulates various histological stages of NASH and faithfully reproduces histological efficacy profiles of compounds in advanced clinical development for NASH. Collectively, these features highlight the utility of GAN DIO-NASH mice in preclinical drug development.
Project description:Nrg4 is a brown fat-enriched adipokine that binds to the liver and suppress the process of steatosis-to-NASH progression. Adipose tissue Nrg4 expression was reduced in mice under NASH diet feeding. Nrg4 homozygous knockout mice are prone to diet-induced steatohepatitis We used microarrays to elucidate the pathogenic pathways that are regulated by Nrg4 deficiency in the livers of mice under NASH diet feeding.
Project description:This study employed low and high-fat purified diets containing two levels of added dietary cholesterol in conventionally raised, specific-pathogen free (SPF) mice harboring a full microbial community as compared to germ-free (GF) mice raised in complete absence of gut microbes on disease outcomes. It was hypothesized that FF-diets would lead to an earlier onset of gut dysbiosis, corresponding with elevated biomarkers of NAFLD and NASH. In the present study, we aimed to dissect the role of FF diet induced gut dysbiosis in order to mechanistically identify the underlying mechanism that influences gut-liver crosstalk between specific diet-induced bacterial populations and hepatic tissue to drive NAFLD/NASH onset and progression
Project description:We applied RNA sequencing (RNA-seq) to study the effects of dietary intervention on hallmarks of NASH and molecular signatures of hepatocellular senescence in the Gubra-Amylin NASH (GAN) diet-induced obese (DIO) mouse model of NASH. GAN DIO-NASH mice with liver biopsy-confirmed NASH and fibrosis received dietary intervention by switching to chow feeding (chow reversal) for 8, 16, or 24 weeks. Untreated GAN DIO-NASH mice and chow-fed C57BL/6J mice served as controls. We find that chow reversal promoted substantial benefits on metabolic, biochemical and histological outcomes accompanied by marked suppression of gene expression markers of hepatocellular senescence in GAN DIO-NASH mice. These therapeutic benefits were reflected by progressive clearance of senescent hepatocellular cells, making the model suitable for profiling potential senotherapeutics in preclinical drug discovery for NASH.
Project description:Background: Chronic inflammation is an important driver in the progression of non-alcoholic steatohepatitis (NASH) and atherosclerosis. The complement system, one of the first lines of defense in innate immunity, has been implicated in both diseases. However, the potential therapeutic value of complement inhibition in the ongoing disease remains unclear. Methods: After 20 weeks of high-fat diet (HFD) feeding, obese Ldlr-/-.Leiden mice were treated twice a week with an established anti-C5 antibody (BB5.1) or vehicle control. A separate group of mice was kept on a chow diet as a healthy reference. After 12 weeks of treatment, NASH was analyzed histopathologically, and genome-wide hepatic gene expression was analyzed by next-generation sequencing and pathway analysis. Atherosclerotic lesion area and severity were quantified histopathologically in the aortic roots. Results: Anti-C5 treatment considerably reduced complement system activity in plasma and MAC deposition in the liver but did not affect NASH. Anti-C5 did, however, reduce the development of atherosclerosis, limiting the total lesion size and severity independently of an effect on plasma cholesterol but with reductions in oxidized LDL (oxLDL) and macrophage migration inhibitory factor (MIF). Conclusion: We show, for the first time, that treatment with an anti-C5 antibody in advanced stages of NASH is not sufficient to reduce the disease, while therapeutic intervention against established atherosclerosis is beneficial to limit further progression.
Project description:We demonstrate that the ketogenic diet a low carbohydrate diet can induce fibrosis and NASH regardless of body weight loss compared to high-fat diet (HFD) fed mice. KD-fed mice develop severe hepatic injury, inflammation, and steatosis. In addition, KD increases IL-6-JNK signaling and aggravates diet induced-glucose intolerance and hepatic insulin resistance compared to HFD. Notably, pharmacological inhibition of IL-6 and JNK reverses KD‐induced glucose intolerance and restores insulin sensitivity.
Project description:<p>Nonalcoholic steatohepatitis (NASH) prevalence is rising with no pharmacotherapy approved. A major hurdle in NASH drug development is the poor translatability of preclinical studies to safe/effective clinical outcomes, and recent failures highlight a need to identify new targetable pathways. Dysregulated glycine metabolism has emerged as a causative factor and therapeutic target in NASH. Here, we report that the tripeptide DT-109 (Gly-Gly-Leu) dose-dependently attenuates steatohepatitis and fibrosis in mice. To enhance the probability of successful translation, we developed a nonhuman primate model that histologically and transcriptionally mimics human NASH. Applying a multiomics approach combining transcriptomics, proteomics, metabolomics and metagenomics, we found that DT-109 reverses hepatic steatosis and prevents fibrosis progression in nonhuman primates, not only by stimulating fatty acid degradation and glutathione formation, as found in mice, but also by modulating microbial bile acid metabolism. Our studies describe a highly translatable NASH model and highlight the need for clinical evaluation of DT-109.</p>