PGC‑1α alternative promoter (Exon 1b) controls augmentation of total PGC‑1α gene expression in response to cold water immersion and low glycogen availability

Abstract

This investigation sought to determine whether post-exercise cold water immersion and low glycogen availability, separately
and in combination, would preferentially activate either the Exon 1a or Exon 1b Peroxisome proliferator-activated
receptor gamma coactivator 1-alpha (PGC-1α) promoter. Through a reanalysis of sample design, we identified that the
systemic cold-induced augmentation of total PGC-1α gene expression observed previously (Allan et al. in J Appl Physiol
123(2):451–459, 2017) was largely a result of increased expression from the alternative promoter (Exon 1b), rather than
canonical promoter (Exon 1a). Low glycogen availability in combination with local cooling of the muscle (Allan et al. in
Physiol Rep 7(11):e14082, 2019) demonstrated that PGC-1α alternative promoter (Exon 1b) expression continued to rise at
3 h post-exercise in all conditions; whilst, expression from the canonical promoter (Exon 1a) decreased between the same
time points (post-exercise–3 h post-exercise). Importantly, this increase in PGC-1α Exon 1b expression was reduced compared
to the response of low glycogen or cold water immersion alone, suggesting that the combination of prior low glycogen and
CWI post-exercise impaired the response in gene expression versus these conditions individually. Data herein emphasise the
influence of post-exercise cooling and low glycogen availability on Exon-specific control