The Role of Mitochondrial ADP/ATP Translocases in Airway Epithelial Cells

Sammanfattning

ANT1 and ANT2, mitochondrial adenine nucleotide translocases, have been implicated in pulmonary diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. They mediate ADP/ATP exchange between the mitochondrial matrix and the cytoplasm. To study the role of ANT1 and ANT2, knockdown and overexpression protocols were established in primary human airway epithelial cells, followed by assessing their effects on ATP levels and cellular senescence. Results showed that siRNA at a concentration of 10 nM and Accell siRNA at a concentration of 1 µM reduced the mRNA expression of ANT1 and ANT2 48 hours post transfection, with an efficiency of 70% and 80%, respectively. Knockdown at the protein level was achieved with 1 µM Accell siRNA 72 hours post transfection. Only ANT1 overexpression was induced using adenoviral vectors. Knockdown of ANT1 and ANT2 lowered ATP production by 12% compared to control, and a 38% increase was detected in ANT1-overexpressing cells compared to cells transduced with the control virus. Senescence was effectively induced with etoposide at a concentration of 3 µM, but no pronounced effects of ANT1 and ANT2 modulation on senescence were observed. In addition, the ANT inhibitor carboxyatractyloside decreased transepithelial electrical resistance and ciliary beating frequency in primary airway epithelial cells differentiated at the air-liquid interface, indicating that ANT1 and ANT2 might play a role in maintaining epithelial barrier function. Our study could serve as a basis for future investigation into the role of ANT1 and ANT2 in chronic respiratory diseases.