The protein ratios of p-DRP1/DRP1 and protein levels of DRP1 and MFF were increased in primary ATII cells from COPD patients compared to non-smokers (p < 0.05, p < 0.001 and p < 0.01 respectively, Fig. 3F–H), whilst the protein levels of MFN2 and OPA1 were reduced in COPD patients compared to non-smokers (p < 0.05 and p < 0.05 respectively, Fig. 3I, J). Here, OPA1 is linked to chronic obstructive pulmonary disease.