Hepatic lipopolysaccharide binding protein partially uncouples inflammation from fibrosis in MAFLD.

Non-alcoholic fatty liver disease (NAFLD), recently renamed metabolic-associated fatty liver disease (MAFLD), is the most common liver disease worldwide. The progression to fibrosis, occurring against a backdrop of hepatic steatosis and inflammation, critically determines liver-related morbidity and mortality. Inflammatory processes contribute to various stages of MAFLD and thought to instigate hepatic fibrosis. For this reason, targeting inflammation has been heavily nominated as a strategy to mitigate liver fibrosis. Lipopolysaccharide binding protein (LBP) is a secreted protein that plays an established role in innate immune responses. Here, using adoptive transfer studies and tissue-specific deletion models we show that hepatocytes are the dominant contributors to circulating LBP. In a murine model of MAFLD, hepatocyte-specific deletion of LBP restrained hepatic inflammation and improved liver function abnormalities, but not measures of fibrosis. Human studies, including genetic evidence, corroborate an important role for LBP in hepatic inflammation with minimal impact on fibrosis. Collectively, our data argues against the idea that targeting hepatic inflammation is a viable approach to reducing fibrosis.

Collaborative interactions of heterogenous ribonucleoproteins contribute to transcriptional regulation of sterol metabolism in mice.

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of functionally versatile proteins that play critical roles in the biogenesis, cellular localization and transport of RNA. Here, we outline a role for hnRNPs in gene regulatory circuits controlling sterol homeostasis. Specifically, we find that tissue-selective loss of the conserved hnRNP RALY enriches for metabolic pathways. Liver-specific deletion of RALY alters hepatic lipid content and serum cholesterol level. In vivo interrogation of chromatin architecture and genome-wide RALY-binding pattern reveal insights into its cooperative interactions and mode of action in regulating cholesterogenesis. Interestingly, we find that RALY binds the promoter region of the master metabolic regulator Srebp2 and show that it directly interacts with coactivator Nuclear Transcription Factor Y (NFY) to influence cholesterogenic gene expression. Our work offers insights into mechanisms orchestrating selective promoter activation in metabolic control and a model by which hnRNPs can impact health and disease states.