The Role of microRNA-1 in Regulating Pyruvate Metabolism in Patients with Peripheral Artery Disease - PROJECT SUMMMARY/ABSTRACT Background: Aging is associated with reduced muscle mass and physical function, which may be exacerbated by age-associated diseases including peripheral artery disease (PAD). PAD affects about 8-12 million individuals in the United States and an estimated 10-15% of the population age ≥65. In PAD, skeletal muscle (SkM) metabolic dysfunction contributes to physical limitation and mobility disability. Few therapies have been identified that improve walking impairment in people with PAD; thus, therapeutic interventions targeting the pathophysiology of the SkM metabolic myopathy are promising. MicroRNAs (miRs) are powerful regulators of gene expression, specifically in the context of energy metabolism. MiRs have great potential as therapeutic agents due to the ability of a single miR to regulate entire pathways. In my preliminary studies, I found that miR-1, the most abundant miR in SkM, appears to play a critical role in hindlimb ischemia models and in human PAD. I developed a genetically modified mouse model for inducible, SkM-specific knockout of miR-1 and found that loss of miR-1 results in metabolic inflexibility and compromised running performance. Utilizing state-of-the-art experimental approaches (Argonaute (AGO) enhanced crosslinking and immunoprecipitation, coupled with high-throughput sequencing (eCLIP-seq)), I identified dysregulation of the pyruvate metabolic pathway as a mechanism for reduced SkM oxidative metabolism with miR-1 loss. Proposed Research: The purpose of this proposal is to define the miR-1 regulated transcriptome and investigate how miR-1 and miR-1 target genes contribute to SkM metabolic myopathy and mobility limitation in experimental PAD as well as in the clinical disease. Aim 1 will identify whether rescuing SkM miR-1 expression will ameliorate ischemic pathology. Aim 2 will determine the role of miR-1 in exercise training adaptations in hindlimb ischemia. Aim 3 will assess miR:target binding in PAD samples to determine pathophysiologically relevant mechanistic targets. Together, these Aims will define the miR-regulated transcriptomic response in PAD and will provide a foundation for the development of miR-based therapeutics aimed at SkM metabolism in PAD. Candidate: I have led projects that investigated several aspects of PAD pathophysiology. I have also led studies that explored miRs in SkM through various novel approaches and technologies. This expertise and my established track record in working with transgenic mouse models will ensure the successful completion of these aims. I will follow up this work and the associated publications with an R01 proposal focused on the role of post-transcriptional regulatory mechanisms in the exercise response heterogeneity in older participants with PAD. The K22 award will be fundamental as I launch my independent investigator career, offering management and grant writing training, helping to hone my skills as a mentor/PI and establish a long-term funded research program.
