Effects of miR-200b-3p inhibition on the TRPC6 and BK Ca channels of podocytes.

Transient receptor potential canonical 6 (TRPC6) and large-conductance Ca2+ -activated K+ channels (BKCa ), two of the key ion channels for blood filtration function of podocytes, have been implicated in the pathogenesis of kidney diseases. Moreover, it has been reported that miR-200 b plays an important role in regulating the biological processes of podocytes. In this study, we aimed to examine whether there was a relationship between miR-200 b-3p and the two ion channels. It was suggested that miR-200 b-3p down-regulation inhibited the currents of TRPC6 and BKCa channels. It also showed that miR-200 b-3p inhibition reduced the levels of protein expression and mRNA transcription of TRPC6 and BKCa channels. Moreover, the down-regulation of miR-200 b-3p resulted in the decrease of the intracellular Ca2+ concentration. It was also suggested that the decrease of BKCa currents resulting from miR-200 b-3p inhibition could be regulated by TRPC6 channels. TRPC6 blockage also inhibited BKCa currents and reduced the level of BKCa expression. These results together suggested that miR-200 b-3p inhibition reduced the currents of TRPC6, which led to the decrease of intracellular Ca2+ concentration. The decrease of Ca2+ source required for BKCa activation may result in the inhibition of BKCa currents.