Abstract
Compromised muscle mitochondrial metabolism is a hallmark of peripheral arterial disease, especially in patients with the most severe clinical manifestation — critical limb ischemia (CLI). We asked whether inflexibility in metabolism is critical for the development of myopathy in ischemic limb muscles. Using Polg mtDNA mutator (D257A) mice, we reveal remarkable protection from hind limb ischemia (HLI) due to a unique and beneficial adaptive enhancement of glycolytic metabolism and elevated ischemic muscle PFKFB3. Similar to the relationship between mitochondria from CLI and claudicating patient muscles, BALB/c muscle mitochondria are uniquely dysfunctional after HLI onset as compared with the C57BL/6 (BL6) parental strain. AAV-mediated overexpression of PFKFB3 in BALB/c limb muscles improved muscle contractile function and limb blood flow following HLI. Enrichment analysis of RNA sequencing data on muscle from CLI patients revealed a unique deficit in the glucose metabolism Reactome. Muscles from these patients express lower PFKFB3 protein, and their muscle progenitor cells possess decreased glycolytic flux capacity in vitro. Here, we show supplementary glycolytic flux as sufficient to protect against ischemic myopathy in instances where reduced blood flow–related mitochondrial function is compromised preclinically. Additionally, our data reveal reduced glycolytic flux as a common characteristic of the failing CLI patient limb skeletal muscle.
Authors
Terence E. Ryan, Cameron A. Schmidt, Michael D. Tarpey, Adam J. Amorese, Dean J. Yamaguchi, Emma J. Goldberg, Melissa M.R. Iñigo, Reema Karnekar, Allison O’Rourke, James M. Ervasti, Patricia Brophy, Thomas D. Green, P. Darrell Neufer, Kelsey Fisher-Wellman, Espen E. Spangenburg, Joseph M. McClung
Figure 1
D257A+/+ (mtDNA mutator) mice display a distinct phenotype.
