Given the important role of angiogenesis in liver pathology, the current study investigated the role of Runt-related transcription factor 1 (RUNX1), a regulator of developmental angiogenesis, in the pathogenesis of non-alcoholic steatohepatitis (NASH). Quantitative RT-PCRs and a transcription factor analysis of angiogenesis-associated differentially expressed genes in liver tissues of healthy controls, patients with steatosis and NASH, indicated a potential role of RUNX1 in NASH. The gene expression of RUNX1 was correlated with histopathological attributes of patients. The protein expression of RUNX1 in liver was studied by immunohistochemistry. To explore the underlying mechanisms, in vitro studies using RUNX1 siRNA and overexpression plasmids were performed in endothelial cells (ECs). RUNX1 expression was significantly correlated with inflammation, fibrosis and NASH activity score in NASH patients. Its expression was conspicuous in liver non-parenchymal cells. In vitro, factors from steatotic hepatocytes and/or VEGF or TGF-β significantly induced the expression of RUNX1 in ECs. RUNX1 regulated the expression of angiogenic and adhesion molecules in ECs, including CCL2, PECAM1 and VCAM1, which was shown by silencing or over-expression of RUNX1. Furthermore, RUNX1 increased the angiogenic activity of ECs. This study reports that steatosis-induced RUNX1 augmented the expression of adhesion and angiogenic molecules and properties in ECs and may be involved in enhancing inflammation and disease severity in NASH.

β-glucans are the dietary nutrients present in oats, barley, algae, and mushrooms. The macromolecules are well known for their immune-modulatory activity; however, how the human gut bacteria digest them is vaguely understood. In this study, Bacteroides uniformis JCM 13288 ^T was found to grow on laminarin, pustulan, and porphyran. We sequenced the genome of the strain, which was about 5.05 megabase pairs and contained 4868 protein-coding genes. On the basis of growth patterns of the bacterium, two putative polysaccharide utilization loci for β-glucans were identified from the genome, and associated four putative genes were cloned, expressed, purified, and characterized. Three glycoside hydrolases (GHs) that were endo-acting enzymes (BuGH16, BuGH30, and BuGH158), and one which was an exo-acting (BuGH3) enzyme. The BuGH3, BuGH16, and BuGH158 can cleave linear exo/endo- β- 1-3 linkages while BuGH30 can digest endo- β- 1-6 linkages. BuGH30 and BuGH158 were further explored for their roles in digesting β- glucans and generation of oligosaccharides, respectively. The BuGH30 predominately found to cleave long chain β- 1-6 linked glucans, and obtained final product was gentiobiose. The BuGH158 used for producing oligosaccharides varying from degree of polymerization 2 to 7 from soluble curdlan. We demonstrated that these oligosaccharides can be utilized by gut bacteria, which either did not grow or poorly grew on laminarin. Thus, B. uniformis JCM 13288 ^T is not only capable of utilizing β-glucans but also shares these glycans with human gut bacteria for potentially maintaining the gut microbial homeostasis.

Hyperammonemia is common in liver cirrhosis and causally associated with hepatic encephalopathy development. Little is known about its hepatotoxic effects, which we aimed to characterize in this study. In a mouse model of chronic hyperammonemia without preexisting liver disease, we observed development of liver fibrogenesis and necroptotic cell death. Hyperammonemia also induced dysregulation of its main metabolic pathway, the urea cycle, as reflected by down-regulation of urea cycle enzyme protein expression and accumulation of its metabolites. Inhibition of receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and its upstream inducer Toll-like receptor 4 (TLR4) protected against liver injury and further hyperammonemia. In clinically relevant rodent models of hyperammonemia (genetic ornithine transcarbamylase deficiency and bile duct ligation–induced cirrhosis), TLR4 inhibition reduced circulating ammonia. In conclusion, hyperammonemia induces liver fibrogenesis and RIPK1-mediated cell death, which is associated with urea cycle dysfunction. Inhibition of RIPK1 and TLR4 protects against hyperammonemia-induced liver injury and are potential therapeutic targets for hyperammonemia and chronic liver disease progression.

Cre-lox system is a powerful and widely used research tool developed to understand the specific role of genes. It allows to control the spatial and temporal expression of genes in experimental models. Several limitations including toxicity of Cre recombinase or incomplete excision of floxed loci have been reported in the past. To date, this is the first research study reporting that gut microbes also influence the expected phenotype of Paneth cell depletion in the genetically modified Math1^lox/loxVilCreER^T2 mouse model.