Regarding BA metabolism, Cyp7A1, NTCP, BSEP, and OATP2 were lower in patients with adiponectin levels below the cutoff (Fig. 4D). In contrast, death receptor expression was increased in patients with MI-503 ic50 lower adiponectin levels (Fig. 4E). Various growth factors, regulatory proteins, and (nuclear) receptors were analyzed for mRNA expression (Fig. 4F), although differences were observed for few targets (MET, KLF6/KLF6SV1,

and LXRa). The principal findings of this study relate BA transporters to hepatocyte apoptosis in NAFLD and uncover a potential role for adiponectin in BA homeostasis. The observations demonstrate a marked induction of genes involved in hepatocellular BA uptake and synthesis, which are repressed by SHP under physiological selleck screening library conditions, in our cohort of superobese individuals. Treatment of hepatoma cells with FFA induces the same BA uptake and synthesis-related genes in a similar fashion. Adiponectin is inversely correlated with serum BAs and hepatocellular injury,

and low adiponectin levels predict simple steatosis as opposed to NASH in obese individuals. Patients with adiponectin levels below 29.16 ng/mL have significantly greater histological features of NASH, higher BA levels, and a lower expression of BA metabolism-related genes, uncovering a novel role for adiponectin and FFA in bile salt metabolism (Fig. 6). The pathogenesis of NAFLD is widely known to be associated with hepatocyte steatosis and FFA-induced lipotoxicity followed by the secretion of proinflammatory cytokines and stellate cell (HSC) activation, which in before the end results in disease progression and fibrosis.21, 22 Since our group and others observed increasing BA concentrations

in NASH, in addition to lipotoxicity, BAs, as products of endogenous hepatic synthesis, may themselves contribute to liver injury in NAFLD.5 In this context, accumulation of BAs in hepatocytes causes hepatocyte death, giant cell hepatitis, and progressive liver damage in hereditary disorders requiring liver transplantation at a young age.23 The mutagenic potential of BAs may even explain the early development of hepatocellular carcinoma in children with hereditary BSEP deficiency.24 Hepatobiliary transport systems are regulated at a transcriptional and posttranscriptional level.9, 25 Nuclear receptors have been identified to function as regulators for positive and negative feedback pathways orchestrating bile formation under different clinical conditions.26 The nuclear BA receptor FXR plays a central role in BA homeostasis and regulates Na+-dependent (NTCP) BA uptake, apart from canalicular excretion (BSEP), as well as the rate-limiting step of BA formation (CYP7A1).27–30 Upon activation by BAs, FXR represses BA uptake and synthesis (NTCP, CYP7A1) by way of SHP and simultaneously activates BA efflux (BSEP).