LncRNA H19-induced AMPKα/LKB1 Complex Is Required for Dihydroartemisinin to Regulate Lipid Droplet Metabolism in Hepatic Stellate Cells

Abstract

Background: Recently, long non-coding RNA-H19 was reported to mediate fatty acids and bile acids metabolism in liver tissue and play important role in fatty liver and cholestatic liver injury. However, little was known about H19 function and mechanism in liver fibrosis. Methods: ICR mice were intoxicated with CCl4 for evaluating H19 and Dihydroartemisinin effects in vivo. HSC-LX2 was cultured and multiple molecular experiments including real-time PCR, western blot, immunofluorescence, oil red staining, nile red staining, dual-luciferase reporter assay, fluorescence in situ hybridization, RNA immunoprecipitation and co-immunoprecipitation were used to elucidate the underlying mechanisms. Results: Decreased expression of H19 significantly ameliorated histopathological feature of liver fibrosis and inhibited HSC activation. This role of H19 was associated with lipid droplet metabolism dependent on AMPKα pathway in HSC. Interestingly, Dihydroartemisinin (DHA) inhibited H19 expression level in a dose-dependent manner. DHA decreased HIF-1α expression level to prevent HIF-1α binding to the promoter of H19. Mechanically, H19 drove AMPKα to interact with LKB1, resulting in the formation of the LKB1/AMPKα complex to facilitate phosphorylation of LKB1 towards AMPKα, causing obvious LDs consumption in HSC, but which was inhibited by DHA. Conclusions: Collectively, H19-induced AMPKα/LKB1 complex was required for DHA to regulate LD metabolism in activated HSC. This study highlighted a new molecular mechanism of DHA against liver fibrosis. Funding Statement: This study was supported by the National Natural Science Foundation of China (81270514, 31571455, 31401210, 31600653, and 81600483), the Natural Science Foundation of Jiangsu Province (BK20140955), the Open Project Program of Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica (No. JKLPSE201804), the Project of the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and the Postgraduate Research& Practice Innovation Program of Jiangsu Province (KYCX19_1262). Declaration of Interests: The authors claim that they have no conflicts of interest. Ethics Approval Statement: All experimental procedures were approved by the Institutional and Local Committee on the Care and Use of Animals of Nanjing University of Chinese Medicine, and all animals received humane care according to the National Institutes of Health (USA) guidelines.