Ku70 modulation alleviates murine allergic asthma features and restores mitochondrial function in lungs.

The airway epithelium is continuously exposed to a variety of pollutants and allergens, thanks to both natural and manmade environmental pollution. With numerous protective mechanisms, the airway epithelium protects the lungs. DNA repair mechanism is one such protective response and its failure could lead to the accumulation of DNA mutations. Our lab had earlier demonstrated the dysfunctional mitochondria in airway epithelium of the asthmatic mice lungs. Here, we show that Ku70 modulation by the administration of Ku70 plasmid attenuates asthma features and reduces mitochondrial dysfunction in the lungs of allergen exposed mice. Ku70 is a key DNA repair protein with diverse roles including VDJ recombination, telomere maintenance, and maintenance of cell homeostasis. Recently, we found a reduction in Ku70 expression in asthmatic airway epithelium, and this was associated with mitochondrial dysfunction in asthmatic condition. In this study, we have shown that Ku70 over-expression in asthmatic mice attenuated airway hyperresponsiveness, airway inflammation, sub-epithelial fibrosis along with reduction in TGF-β with no effect in IL-13 levels and goblet cell metaplasia. Ku70 over-expression in asthmatic mice reduced 8-isoprostane, a marker of oxidative stress, and restored the mitochondrial function in asthmatic mice. We further found these roles of Ku70 to be independent of DNA damage as Ku70 overexpressed mice did not show any reduction in DNA tail, an index of DNA damage. Thus, our findings indicate that Ku70 can attenuate crucial features of asthma along with the restoration of mitochondrial function. This implies that Ku70 could be a therapeutic target for asthma without affecting DNA repair function.