Post-exercise cold-water immersion increases Na+,K+-ATPase α2-isoform mRNA content in parallel with elevated Sp1 expression in human skeletal muscle

Abstract

AbstractWe investigated the effect of a session of sprint-interval exercise on the mRNA content of NKA isoforms (α1-3, β1-3) and FXYD1 in human skeletal muscle. To explore some of the cellular stressors involved in this regulation, we evaluated the association between these mRNA responses and those of the transcription factors Sp1, Sp3 and HIF-1α. Given cold exposure perturbs muscle redox homeostasis, which may be one mechanism important for increases in NKA-isoform mRNA, we also explored the effect of post-exercise cold-water immersion (CWI) on the mRNA responses. Muscle was sampled from nineteen men before (Pre) and after (+0h, +3h) exercise plus passive rest (CON, n=10) or CWI (10°C; COLD, n=9). In COLD, exercise increased NKAα2 and Sp1 mRNA (+0h, p<0.05). These genes remained unchanged in CON (p>0.05). In both conditions, exercise increased NKAα1, NKAβ3 and HIF-1α mRNA (+3h; p <0.05), decreased NKAβ2 mRNA (+3h; p<0.05), whereas NKAα3, NKAβ1, FXYD1 and Sp3 mRNA remained unchanged (p>0.05). These human findings highlight 1) sprint-interval exercise increases the mRNA content of NKA α1 and β3, and decreases that of NKA β2, which may relate, in part, to exercise-induced muscle hypoxia, and 2) post-exercise CWI augments NKAα2 mRNA, which may be associated with promoted Sp1 activation.