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Biochem Biophys Res Commun. 2014 Oct 24;453(3):411-8. doi: 10.1016/j.bbrc.2014.09.094. Epub 2014 Sep 28.

Caffeine promotes autophagy in skeletal muscle cells by increasing the calcium-dependent activation of AMP-activated protein kinase.

Author information

1
Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, SC, USA.
2
Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA.
3
Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, SC, USA. Electronic address: bbaumgar@uscupstate.edu.

Abstract

Caffeine has been shown to promote calcium-dependent activation of AMP-activated protein kinase (AMPK) and AMPK-dependent glucose and fatty acid uptake in mammalian skeletal muscle. Though caffeine has been shown to promote autophagy in various mammalian cell lines it is unclear if caffeine-induced autophagy is related to the calcium-dependent activation of AMPK. The purpose of this study was to examine the role of calcium-dependent AMPK activation in regulating caffeine-induced autophagy in mammalian skeletal muscle cells. We discovered that the addition of the AMPK inhibitor Compound C could significantly reduce the expression of the autophagy marker microtubule-associated protein 1 light chain 3b-II (LC3b-II) and autophagic vesicle accumulation in caffeine treated skeletal muscle cells. Additional experiments using pharmacological inhibitors and RNA interference (RNAi) demonstrated that the calcium/calmodulin-activated protein kinases CaMKKβ and CaMKII contributed to the AMPK-dependent expression of LC3b-II and autophagic vesicle accumulation in a caffeine dose-dependent manner. Our results indicate that in skeletal muscle cells caffeine increases autophagy by promoting the calcium-dependent activation of AMPK.

KEYWORDS:

AMP-activated protein kinase; Autophagy; Caffeine; Calcium; Calcium/calmodulin-activated protein kinase II

PMID:
25268764
DOI:
10.1016/j.bbrc.2014.09.094
[Indexed for MEDLINE]

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