PPARGC1A mRNA levels of in vitro differentiated human skeletal muscle cells are negatively associated with the plasma oleate concentrations of the donors

Excerpt

To the Editor: Peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1α (PGC-1α) is a metabolically relevant transcriptional coactivator protein. Through PPARs and nuclear respiratory factor-1, it enhances adaptive thermogenesis, oxidative phosphorylation, mitochondrial biogenesis and β-oxidation in adipose tissue and skeletal muscle [1]. Obese, insulin-resistant and type 2 diabetic states reveal low muscle mitochondrial oxidative capacity, reduced expression of respiratory chain components, and decreased expression of the gene encoding PGC-1α (PPARGC1A) [2, 3]. We have recently shown that PPARGC1A expression in in vitro differentiated human skeletal muscle cells (myotubes) is induced by common unsaturated plasma NEFAs, such as palmitoleate, oleate and linoleate, but is not influenced by common saturated NEFAs, such as myristate, palmitate and stearate [4]. In the present study, we investigated (1) whether the basal expression of PPARGC1A and the gene encoding its close homologue, PGC-1β (PPARGC1B) in myotubes derived from metabolically characterised white donors display marked individual variations, and, if so, (2) whether these variations are linked to in vivo metabolic features of the donors, such as adiposity, insulin resistance, total NEFA concentration, or concentration of individual plasma NEFAs. …