PPARGC1A and chronic obstructive pulmonary disease: Of interest, the mRNA expression of both PINK1, a marker not significantly different in CSE exposed BEAS-2B cells (Online Additional file 1), and PPARGC1α, a marker that was not detectable in CSE exposed BEAS-2B cells, was significantly increased in PBECs from COPD patients when compared to non-smoking controls (Figure 5B).