TY - JOUR T1 - Induced pluripotent stem cell derived podocyte like cells as models for assessing mechanisms underlying heritable disease phenotype: initial studies using two Alport syndrome patient lines indicate impaired potassium channel activity JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther DO - 10.1124/jpet.118.250142 SP - jpet.118.250142 AU - John M Haynes AU - James N Selby AU - Isaiah PL Abad AU - Teresa Vandekolk AU - Joan K Ho AU - Wai-Ling Lieuw AU - Katie Leach AU - Judith Savige AU - Sheetal Saini AU - Craig Fisher AU - Sharon Ricardo Y1 - 2018/01/01 UR - http://jpet.aspetjournals.org/content/early/2018/08/13/jpet.118.250142.abstract N2 - Renal podocyte survival depends upon the dynamic regulation of a complex cell architecture that links glomerular basement membrane to integrins, ion channels and receptors. Alport syndrome is a heritable chronic kidney disease where mutations in α3, α4 or α5 collagen genes promote podocyte death. In rodent models of renal failure, activation of the calcium sensing receptor (CaSR) can protect podocytes from stress related death. In this study we assess CaSR function in podocyte-like cells from induced-pluripotent stem cells derived from two patients with Alport Syndrome (AS1 & AS2), a renal disease free individual (NHMC) and an immortalized podocyte-like (HIP) cell line. Extracellular calcium elicited concentration-dependent elevations of intracellular calcium in all podocyte-like cells. NHMC and HIP, but not AS1 or AS2 podocyte-like cells also showed acute reductions in intracellular calcium prior to elevation. In NHMC podocyte-like cells this acute reduction was blocked by the large conductance potassium channel (KCNMA1) inhibitors iberiotoxin (10nM) and tetraethylammonium (5 mM), as well as the focal adhesion kinase inhibitor PF562271 (10nM). Quantitative PCR and immunolabelling showed the presence of KCNMA1 transcript and protein in all podocyte-like cells tested. Cultivation of AS1 podocytes on decellularized plates of NHMC podocyte-like cells partially restored acute reductions in intracellular calcium in response to extracellular calcium. We conclude that the AS patient-derived podocyte-like cells used in this study show dysfunctional integrin signalling and potassium channel function which may contribute to podocyte death seen in Alport syndrome. ER -