Antimycin A-induced mitochondrial dysfunction is consistent with impaired insulin signaling in cultured skeletal muscle cells

Sithandiwe E. Mazibuko-Mbeje, Sinenhlanhla X.H. Mthembu, Phiwayinkosi V. Dludla, Evelyn Madoroba, Nireshni Chellan, Abidemi P. Kappo, Christo J.F. Muller

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Insulin resistance and mitochondrial dysfunction are characteristic features of type 2 diabetes mellitus. However, a causal relationship between insulin resistance and mitochondrial dysfunction has not been fully established in the skeletal muscle. Accordingly, we have evaluated the effect of antimycin A (AA), a mitochondrial electron transport chain complex III inhibitor, on mitochondrial bioenergetics and insulin signaling by exposing C2C12 skeletal muscle cells to its concentrations of 3.125, 6.25, 12.5, 25, and 50 μM for 12 h. Thereafter, metabolic activity, ROS production, glucose uptake, Seahorse XF Real-time ATP and Mito Stress assays were performed. Followed by real-time polymerase chain reaction (RT-PCR) and Western blot analysis. This study confirmed that AA induces mitochondrial dysfunction and promote ROS production in C2C12 myotubes, culminating in a significant decrease in mitochondrial respiration and downregulation of genes involved in mitochondrial bioenergetics (TFAM, UCP2, PGC1α). Increased pAMPK and extracellular acidification rates (ECAR) confirmed a potential compensatory enhancement in glycolysis. Additionally, AA impaired insulin signaling (protein kinase B/AKT) and decreased insulin stimulated glucose uptake. This study confirmed that an adaptive relationship exists between mitochondrial functionality and insulin responsiveness in skeletal muscle. Thus, therapeutics or interventions that improve mitochondrial function could ameliorate insulin resistance as well.

Original languageEnglish
Article number105224
JournalToxicology in Vitro
Volume76
DOIs
Publication statusPublished - Oct 2021

Keywords

  • Antimycin A
  • Bioenergetics
  • Diabetes
  • Insulin resistance
  • Mitochondria
  • Skeletal muscle

ASJC Scopus subject areas

  • Toxicology

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