Caffeine-stimulated fatty acid oxidation is blunted in CD36 null mice
Aim: The increase in skeletal muscle fatty acid metabolism during exercise has been associated with the release of calcium. We examined whether this increase in fatty acid oxidation was attributable to a calcium‐induced translocation of the fatty acid transporter CD36 to the sarcolemma, thereby prov...
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Published in | Acta Physiologica Vol. 205; no. 1; pp. 71 - 81 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Stockholm
Blackwell Publishing Ltd
01.05.2012
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Aim:
The increase in skeletal muscle fatty acid metabolism during exercise has been associated with the release of calcium. We examined whether this increase in fatty acid oxidation was attributable to a calcium‐induced translocation of the fatty acid transporter CD36 to the sarcolemma, thereby providing an enhanced influx of fatty acids to increase their oxidation.
Methods:
Calcium release was triggered by caffeine (3 mm) to examine fatty acid oxidation in intact soleus muscles of WT and CD36‐KO mice, while fatty acid transport and mitochondrial fatty acid oxidation were examined in giant vesicles and isolated mitochondria, respectively, from caffeine‐perfused hindlimb muscles of WT and CD36‐KO mice. Western blotting was used to examine calcium‐induced signalling.
Results:
In WT, caffeine stimulated muscle palmitate oxidation (+136%), but this was blunted in CD36‐KO mice (−70%). Dantrolene inhibited (WT) or abolished (CD36‐KO) caffeine‐induced palmitate oxidation. In muscle, caffeine‐stimulated palmitate oxidation was not attributable to altered mitochondrial palmitate oxidation. Instead, in WT, caffeine increased palmitate transport (+55%) and the translocation of fatty acid transporters CD36, FABPpm, FATP1 and FATP4 (26–70%) to the sarcolemma. In CD36‐KO mice, caffeine‐stimulated FABPpm, and FATP1 and 4 translocations were normal, but palmitate transport was blunted (−70%), comparable to the reductions in muscle palmitate oxidation. Caffeine did not alter the calcium‐/calmodulin‐dependent protein kinase II phosphorylation but did increase the phosphorylation of AMPK and acetyl‐CoA carboxylase comparably in WT and CD36‐KO.
Conclusion:
These studies indicate that sarcolemmal CD36‐mediated fatty acid transport is a primary mediator of the calcium‐induced increase in muscle fatty acid oxidation. |
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Bibliography: | Natural Sciences and Engineering Research Council of Canada European Community - No. LSHM-CT-2004-005272 ark:/67375/WNG-ZFQMT93R-1 istex:83E366EDD23C259F81E0DFC62CDDABCEF5C9203E ArticleID:APHA2396 Canadian Institutes of Health Research ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1748-1708 1748-1716 |
DOI: | 10.1111/j.1748-1716.2012.02396.x |