Alcohol-associated skeletal muscle mitochondrial dysfunction: insights into Sirt1 regulation

Abstract

Alcohol-induced skeletal muscle dysfunction affects approximately 50% of individuals with alcohol use disorder (AUD). Alcohol dysregulates mitochondrial oxidative metabolism and promotes oxidative stress. However, the impact of alcohol on skeletal muscle bioenergetic capacity and cellular redox balance remain to be fully elucidated. The expression and activity of Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, is dysregulated with ethanol metabolism. This disruption has the potential to play a significant role in the intricate regulatory network responsible for alcohol-induced mitochondrial dysfunction in skeletal muscle. Interventional strategies, such as exercise, have the potential to enhance mitochondrial function and promote overall skeletal muscle health. We hypothesize that alcohol dysregulates myotube mitochondrial bioenergetics by reducing mitochondrial respiration in a Sirt1-dependent manner, and we predict that simulating exercise through electrical pulse stimulation will increase Sirt1 expression. Myoblasts were differentiated into myotubes in the presence of ethanol (0 and 50 mM) for 3 days prior to Mito Stress Test using the Seahorse XF Pro Analyzer. Differentiated myotubes treated with ethanol (0 and 50 mM, for 3 days), were exposed to electrical pulse stimulation simulating exercise (30V, 1Hz, 2ms pulses) for 24 h. A mixed-effects model with Šidák correction and repeated samples t-test was used. Means with p-value of less than 0.05 were considered statistically significant. Preliminary analysis indicates significant decrease in ATP-linked mitochondrial respiration (p<0.05) in the presence of ethanol. Ethanol also decreased myotube Sirt1 activity (p<0.05) and Sirt3 protein expression. There was a main effect of electrical pulse stimulation to increase Sirt1 activity (p<0.001) in both the control and ethanol-treated groups. Ongoing analysis will identify alcohol-mediated changes in proteins involved in mitochondrial dynamics regulated by Sirt1. These results show that ethanol significantly decreases mitochondrial bioenergetics in differentiated human myotubes. The ethanol induced changes in Sirt1 activity and Sirt3 protein expression, suggest a potential role of Sirt1-mediated mitochondrial dysregulation with alcohol. This research was supported by NIH/NIAAA T32AA007577, P60AA009803 (PEM) and R21AA030869 (LS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.