Skeletal muscle miR-34a/SIRT1:AMPK axis is activated in experimental and human non-alcoholic steatohepatitis

AbstractNon-alcoholic fatty liver disease (NAFLD) pathogenesis associates with intramyocellular lipid deposition and mitochondrial dysfunction. microRNAs (miRs), including pro-apoptotic miR-34a, are modulated during disease progression in liver tissue and plasma. We aimed to investigate the functional role of the miR-34a/SIRT1:AMP-activated protein kinase (AMPK) pathway in modulating local mitochondrial dysfunction in the skeletal muscle of human and experimental non-alcoholic steatohepatitis. Muscle biopsies were obtained from morbid obese NAFLD patients undergoing bariatric surgery. C57BL/6N mice were fed different NAFLD-inducing diets and C2C12 muscle cells incubated with palmitic acid (PA) in the presence or absence of an AMPK activator, or upon miR-34a functional modulation. Several muscle miRNAs, including miR-34a, were found increased with human NAFLD progression. Activation of the miR-34a/SIRT1:AMPK pathway, concomitant with impairment in insulin signalling mediators and deregulation of mitochondrial-shaping proteins, was evident in C2C12 cells incubated with PA, as well as in the skeletal muscle of all three diet-induced NAFLD mice models. Functional studies established the association between miR-34a- and PA-induced muscle cell deregulation. Of note, activation of AMPK almost completely prevented miR-34a- and PA-induced cellular stress. In addition, the miR-34a/SIRT1:AMPK pathway and mitochondrial dynamics dysfunction were also found amplified in muscle of human NAF...
Source: Journal of Molecular Medicine - Category: Molecular Biology Source Type: research