Disentangling genetic, epigenetic and hormonal regulation of Fe/heme metabolism in the gender-specific nature of NAFLD (DEFENDER)

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases, ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma, with limited treatment options. NAFLD/NASH incidence is lower in fertile women compared to men and post-menopausal women, suggesting a pivotal role exerted by estrogen signaling in counteracting NAFLD development and progression. Despite this evidence, little attention has been paid to investigate the role of biological drivers responsible for the sexually dimorphic nature of NAFLD, preventing the design of sex-specific strategies useful to counteract progression to NASH. Increased hepatic iron levels and dysregulation of heme metabolism are frequently observed in patients with NAFLD and several lines of evidence suggest that the preferential male predisposition to hepatic iron accumulation may account for the higher rate of NAFLD/NASH prevalence in males with respect to females. According to this view, preliminary data from RNA-Seq analysis indicate that key players involved in iron/heme signaling pathways are differentially regulated in the liver of male and female mice under physiological conditions. The driving hypothesis of DEFENDER is based on the idea that the sexual dimorphic dysregulation of heme and iron metabolism might contribute to sex differences in NAFLD development and progression. The main goal of DEFENDER is to disentangle the contribution of genetic, epigenetic and hormonal key players involved in the regulation of iron/heme signaling pathway to the sexually dimorphic nature of NAFLD, by investigating in mouse livers and human cell models of NAFLD changes in transcriptomics and histological features, in relation to sex and hormonal status. In addition, DEFENDER aims to assess the targeting of heme/iron signaling pathway in liver organoids and assembloids as a valuable tool to test the potential of a new pharmacological approach to limit NAFLD progression in a sex-specific fashion. The achievement of DEFENDER objectives will allow: a) to improve our understanding of the biological processes driving NAFLD/NASH in a sex-specific fashion; b) to clarify the specific relevance of hepatic iron and heme signaling pathways to sex differences in NAFLD/NASH physiopathology; c) to provide new ground for the design of sex-specific pharmacological strategies aimed to preserve healthy liver functions and counteract NAFLD/NASH.