PPARGC1A and chronic obstructive pulmonary disease: Thus, whereas our data support some aspects of the previous suggestion of a normal mitochondrial biogenesis response in COPD muscle by showing the coupling between PGC-1α and TFAM transcription is maintained, in sharp contrast to a normal response, we also show a marked uncoupling between TFAM transcript levels and TFAM protein, suggesting a problem in TFAM translation in COPD muscle.