PGC-1α increases skeletal muscle lactate uptake by increasing the expression of MCT1 but not MCT2 or MCT4

Benton CR, Yoshida Y, Lally J, Han X-X, Hatta H, Bonen A. PGC-1 alpha increases skeletal muscle lactate uptake by increasing the expression of MCT1 but not MCT2 or MCT4. Physiol Genomics 35: 45-54, 2008. First published June 3, 2008; doi: 10.1152/physiolgenomics.90217.2008.-We examined the relationship between PGC-1 alpha protein; the monocarboxylate transporters MCT1, 2, and 4; and CD147 1) among six metabolically heterogeneous rat muscles, 2) in chronically stimulated red (RTA) and white tibialis (WTA) muscles (7 days), and 3) in RTA and WTA muscles transfected with PGC-1 alpha-pcDNA plasmid in vivo. Among rat hind-limb muscles, there was a strong positive association between PGC-1 alpha and MCT1 and CD147, and between MCT1 and CD147. A negative association was found between PGC-1 alpha and MCT4, and CD147 and MCT4, while there was no relationship between PGC-1 alpha or CD147 and MCT2. Transfecting PGC-1 alpha-pcDNA plasmid into muscle increased PGC-1 alpha protein (RTA + 23%; WTA + 25%) and induced the expression of MCT1 (RTA + 16%; WTA + 28%), but not MCT2 and MCT4. As a result of the PGC-1 alpha-induced upregulation of MCT1 and its chaperone CD147 (+29%), there was a concomitant increase in the rate of lactate uptake (+20%). In chronically stimulated muscles, the following proteins were upregulated, PGC-1 alpha in RTA (+26%) and WTA (+86%), MCT1 in RTA (+61%)and WTA (+180%), and CD147 in WTA (+106%). In contrast, MCT4 protein expression was not altered in either RTA or WTA muscles, while MCT2 protein expression was reduced in both RTA (-14%) and WTA (-10%). In these studies, whether comparing oxidative capacities among muscles or increasing their oxidative capacities by PGC-1 alpha transfection and chronic muscle stimulation, there was a strong relationship between the expression of PGC-1 alpha and MCT1, and PGC-1 alpha and CD147 proteins. Thus, MCT1 and CD147 belong to the family of metabolic genes whose expression is regulated by PGC-1 alpha in skeletal muscle.