Tmem63c is a potential pro-survival factor in angiotensin II-treated human podocytes

Human podocytes (hPC) play an important role in the pathogenesis of renal diseases. In this context, angiotensin II (Ang II) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) play a crucial role in podocyte injury. Recently, transmembrane protein (Tmem) 63c, a member of the Tmem-family was found to be expressed in kidney and associated with podocyte function. In this study, we analysed the expression regulation and functional impact of Tmem63c on cell viability and apoptosis in hPC in the context of Ang II activation.

Expression of Tmem63c in response to Ang II and the NFκB inhibitor Bay 11-7082 was analysed by Real-Time PCR and Western blotting. Cellular functions were determined by functional assays.

We found Ang II to induce Tmem63c expression in hPC in a concentration-dependent manner. Inhibition of NFκB by Bay 11-7082 reduced basal as well as Ang II-induced Tmem63c expression. SiRNA-mediated down-regulation of Tmem63c diminished cell viability and protein kinase B (Akt) signaling and increased cell apoptosis of resting as well as Ang II-activated hPC.

These data show that Ang II induced the expression of Tmem63c in hPC, possibly via NFκB-dependent mechanisms. Moreover, down-regulation of Tmem63c was associated with reduced cell viability, indicating Tmem63c to be a potential pro-survival factor in hPC.