MiR-339-3p aggravates rat vascular inflammation induced by AT1R autoantibodies by down-regulating BKα protein expression

The abnormality of large-conductance calcium-activated potassium channels (BK channels) is an important factor in inducing vascular inflammation. BK channel agonists can readily recover BK channel function and improve vascular inflammation. However, it is not clear how to improve BK dysfunction caused by downregulation of BK channel protein expression. This study found that angiotensin II-1 receptor autoantibodies (AT1-AA), which are widely present in the body of various types of cardiovascular diseases, can down-regulate the expression of BK channel protein and induce vascular inflammation. Further research found that the elevated neural precursor cells expressed developmentally downregulated 4-like (NEDD4L) protein level is involved in the down-regulation of BK channel subunit (BK) protein level by AT1-AA. Bioinformatics analysis and experiments have confirmed that miR-339-3p plays an irreplaceable role in the high expression of NEDD4L and the low expression of BK, and aggravates the vascular inflammation induced by AT1-AA. Overall, AT1-AA increased miR-339-3p expression (targeting BK via the miR-339-3p/NEDD4L axis or miR-339-3p alone), reduced BK protein expression in VSMCs, and induced vascular inflammation. The results of the study indicate that miR-339-3p may become a new target for reversing vascular inflammation in AT1-AA-positive patients.