A single bout of resistance exercise triggers mitophagy, potentially involving the ejection of mitochondria in human skeletal muscle

Francisco Díaz-Castro, Mauro Tuñón-Suárez, Patricia Rivera, Javier Botella, Jorge Cancino, Ana María Figueroa, Juan Gutiérrez, Claudette Cantin, Louise Deldicque, Hermann Zbinden-Foncea, Joachim Nielsen, Carlos Henríquez-Olguín, Eugenia Morselli, Mauricio Castro-Sepúlveda

Research output: Contribution to journalArticlepeer-review

Abstract

Aim: The present study aimed to investigate the effects of a single bout of resistance exercise on mitophagy in human skeletal muscle (SkM). Methods: Eight healthy men were recruited to complete an acute bout of one-leg resistance exercise. SkM biopsies were obtained one hour after exercise in the resting leg (Rest-leg) and the contracting leg (Ex-leg). Mitophagy was assessed using protein-related abundance, transmission electron microscopy (TEM), and fluorescence microscopy. Results: Our results show that acute resistance exercise increased pro-fission protein phosphorylation (DRP1Ser616) and decreased mitophagy markers such as PARKIN and BNIP3L/NIX protein abundance in the Ex-leg. Additionally, mitochondrial complex IV decreased in the Ex-leg when compared to the Rest-leg. In the Ex-leg, TEM and immunofluorescence images showed mitochondrial cristae abnormalities, a mitochondrial fission phenotype, and increased mitophagosome-like structures in both subsarcolemmal and intermyofibrillar mitochondria. We also observed increased mitophagosome-like structures on the subsarcolemmal cleft and mitochondria in the extracellular space of SkM in the Ex-leg. We stimulated human primary myotubes with CCCP, which mimics mitophagy induction in the Ex-leg, and found that BNIP3L/NIX protein abundance decreased independently of lysosomal degradation. Finally, in another human cohort, we found a negative association between BNIP3L/NIX protein abundance with both mitophagosome-like structures and mitochondrial cristae density in the SkM. Conclusion: The findings suggest that a single bout of resistance exercise can initiate mitophagy, potentially involving mitochondrial ejection, in human skeletal muscle. BNIP3L/NIX is proposed as a sensitive marker for assessing mitophagy flux in SkM.

Original languageEnglish
Article numbere14203
JournalActa Physiologica
Volume240
Issue number9
DOIs
StatePublished - 1 Sep 2024

Keywords

  • BNIP3L/NIX
  • mitochondria cristae
  • mitochondria dynamics
  • mitophagy

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