Regulation and role of glycophagy in skeletal muscle energy metabolism

Research output: Contribution to journalArticlepeer-review

Abstract

Glycophagy is the autophagic degradation of glycogen via the lysosomal enzyme GAA/alpha-acid glucosidase. Glycophagy is considered a housekeeping process to degrade poorly branched glycogen particles, but the regulation and role of glycophagy in skeletal muscle metabolism remains enigmatic. Herein, prior muscle contraction promoted glycogen supercompensation 24 and 48 h post contraction, an effect associated with reduced glycophagy. Moreover, NOTCH or cAMP signaling promoted glycophagy, whereas acute glycophagy deficiency rewired cell metabolism by reducing glycolysis and enhancing AMPK and PPAR signaling and fatty acid and glutamine metabolism. These metabolic adaptations were associated with reduced inflammation and triglyceride content but enhanced phosphoinositide 3-kinase (PI3K)-AKT/protein kinase B signaling and insulin action, the latter of which was abolished by exogenous oxidative stress. Collectively, these data suggest glycophagy is dynamically regulated, while the function of glycophagy can be extended beyond a housekeeping process to having an additional role in regulating energy metabolism and insulin action. Abbreviations: AMPK, AMP-activated protein kinase; ASM, acid soluble metabolites; cAMP, cyclic adenosine monophosphate; EPS, electrical pulse stimulation; FCCP, carbonyl cyanide-p-trifluoromethoxyphenylhydrazone; GAA, glucosidase, alpha, acid; mTOR, mechanistic target of rapamycin kinase; NAD, nicotinamide adenine dinucleotide; PARP, poly (ADP-ribose) polymerase family; PI3K, phosphoinositide 3-kinase; PPAR, peroxisome proliferator activated receptor; PYGM, muscle glycogen phosphorylase; STBD1, starch binding domain 1; TFEB, transcription factor EB.

Original languageEnglish (US)
Number of pages12
JournalAutophagy
Early online dateSep 10 2021
DOIs
StatePublished - Sep 10 2021

Bibliographical note

Publisher Copyright:
© 2021 Informa UK Limited, trading as Taylor & Francis Group.

Keywords

  • Alpha acid glucosidase
  • fatty acid oxidation
  • glutamine
  • glycogen supercompensation
  • glycolysis
  • insulin action

PubMed: MeSH publication types

  • Journal Article

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