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DOI: 10.1055/s-0038-1677189
The RNA binding protein HuR is a master regulator of hepatic-lipid homeostasis
Publication History
Publication Date:
04 January 2019 (online)
RNA binding proteins (RBP) play an essential role in the post-transcriptional control of RNAs. Less is known about the role of RBPs in the liver, particularly the hepatocyte-specific function. The RBP, HuR (encoded by Elavl1; embryonic lethal abnormal vision like 1) regulates mRNA splicing and stability. We found that HuR is diminished in human livers with steatosis and/or non-alcoholic steatohepatitis (NASH) and that it regulates a network of pathways that are essential in hepatic-lipid homeostasis maintenance. Hepatocyte-specific HuR deficient mice exhibited severe steatosis of the liver already at steady state, as compared to their wild type littermates. This phenotype was further enhanced in a model of diet-induced NASH, whereby HuR deficiency promoted inflammation and fibrosis development. Lipidomic analysis revealed that, HuR deficient livers at steady state accumulated a triglyceride-signature resembling that of NASH-livers of HuR sufficient mice. Moreover, hepatocyte-protective bile acid species were reduced, whereas, proinflammatory lipid mediators such as leukotrienes were induced in the absence of HuR, as studied by metabolomics. By studying HuR-RNA interactions in the liver, we found that HuR binds to targets involved in various lipid metabolic processes and that it prevents the hepatic-accumulation of adverse lipid species. The current study emphasizes how post-transcriptional processes control lipid metabolism to maintain homeostasis in the liver.