Quadriceps miR-542-3p and 5p are elevated in COPD and reduce function by inhibiting ribosomal and protein synthesis

Reduced physical performance reduces quality of life in patients with COPD. Impaired physical performance is, in part, a consequence of reduced muscle mass and function, which is accompanied by mitochondrial dysfunction. We recently showed that miR-542-3p and miR-542-5p were elevated in a small cohort of COPD patients and more markedly in critical care patients. In mice these miRNAs promoted mitochondrial dysfunction suggesting that they would affect physical performance in patients with COPD but we did not explore the association of these miRNAs with disease severity or physical performance further. We therefore quantified miR-542-3p/5p and mitochondrial rRNA expression in RNA extracted from quadriceps muscle of patients with COPD and determined their association with physical performance. As miR-542-3p inhibits ribosomal protein synthesis its ability to inhibit protein synthesis was also determined in vitro.Both miR-542-3p and -5p expression were elevated in patients with COPD (5-fold p