Enhanced inflammatory damage by microRNA-136 targeting Klotho expression in HK-2 cells by modulating JAK/STAT pathway.

MiR-136 acts as a tumor suppressor by promoting cell apoptosis and downregulating Bcl-2 in glioma cells. Hence, an attempt has been made to evaluate the role of miR-136 in regulation of inflammatory damage in HK-2 cells. HK-2 cells were cultured and assessed for viability. The cells were then transfected with miR-136 mimic, si- miR-136, si-Klotho, and NC. Dual luciferase test was performed to confirm the target of miR-136 which was assumed to be Klotho. Cell viability, apoptosis, expressions of inflammatory cytokines like TNF-α, IL-1β, IL-6 and IL-8 were assessed in HK-2 cells with overexpressing miR-136 or with knocked down miR-136 activities, following exposure to LPS. LPS induced inflammatory damage decreased cell viability, induced cell apoptosis, and increased the expression of different inflammatory cytokines. It was found that LPS decreased the expression of miR-136. Over-expression of miR-136 inhibited cell viability, enhanced apoptosis, and increased expression of inflammatory cytokines while knockdown of miR-136 showed opposite results with p-values < 0.05. MiR-136 negatively regulated the expression of Klotho with p-value < 0.05. Over-expression of miR-136 inhibited the expression of Klotho and activated JAK/STAT and mTOR signaling pathways and vice versa. Hence, it can be concluded that miR-136 enhances inflammatory damage probably by targeting klotho as has been observed in luciferase assay by inactivation of JAK/STAT and mTOR signaling pathways.