Abstract Alcohol-mediated mitochondrial adaptations in skeletal muscle: role of Sirtuin1 The goal of this Ruth L. Kirschstein NRSA F32 application is to prepare the applicant for an academic career as an alcohol researcher. The applicant will have the invaluable opportunity to be trained in alcohol research, and transition from basic science research to translational research. Alcohol-induced skeletal muscle dysfunction affects 50% of individuals with alcohol use disorder. Skeletal muscle mitochondrial dysfunction is a salient mechanism contributing to myopathy and data from the laboratory demonstrates that alcohol increases reactive oxygen species production and reduces mitochondrial membrane potential in primary skeletal muscle myoblasts. However, the alcohol-mediated specific mechanisms leading to impaired bioenergetic capacity and disrupted cellular redox homeostasis in skeletal muscle remain incompletely understood. Sirtuin-1 (SIRT1), a NAD+- dependent class-III protein deacetylase, regulates mitochondrial dynamics, biogenesis, and bioenergetic capacity. The inhibition of SIRT1 is correlated with increased mitochondrial fission, and exercise-induced increases in NAD+ levels increase skeletal muscle SIRT1 activity, positively influencing energy metabolism. We postulate that these alterations arise from increased mitochondrial fission, driven by decreased Sirt1 activity. Preliminary data generated for this application indicate that in differentiated primary human myotubes, electrical pulse stimulation increases ethanol-induced reductions in Sirt1 activity. However, the precise mechanisms by which Sirt1-induced deacetylation impacts mitochondrial dynamics and contributes to alcohol-mediated dysregulated skeletal muscle bioenergetics remain incompletely understood. Taken together, preliminary data and published literature provide evidence of alcohol-mediated mitochondrial adaptations leading to skeletal muscle dysfunction. We hypothesize that alcohol dysregulates mitochondrial bioenergetics in myotubes derived from humans by increasing mitochondrial fission and reducing mitochondrial respiration, in a Sirt1 dependent manner. Additionally, we propose to explore the potential of electrical pulse stimulation to identify the alcohol- associated mitochondrial dysfunction mechanisms that can be positively influenced by exercise. With a strong mentoring team, including clinician scientists, completion of the proposed training plan in alcohol-related research will ensure that the applicant is equipped for a successful career in alcohol translational research.