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

John M. Haynes, James N. Selby, Teresa H. Vandekolk, Isaiah P. L. Abad, Joan K. Ho, Wai-Ling Lieuw, Katie Leach, Judith Savige, Sheetal Saini, Craig L. Fisher, Sharon D. Ricardo

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5 Citations (Scopus)

Abstract

Renal podocyte survival depends upon the dynamic regulation of a complex cell architecture that links the glomerular basement membrane to integrins, ion channels, and receptors. Alport syndrome is a heritable chronic kidney disease where mutations in a3, a4, or a5 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 assessed CaSR function in podocyte-like cells derived from induced-pluripotent stem cells from two patients with Alport Syndrome (AS1 & AS2) and a renal disease free individual [normal human mesangial cell (NHMC)], as well as a human 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 (10 nM) and tetraethylammonium (5 mM), as well as the focal adhesion kinase inhibitor PF562271 (N-methyl-N-(3-((2-(2-oxo-2,3-dihydro-1H-indol- 5-ylamino)-5-trifluoromethyl-pyrimidin-4-ylamino)-methyl)-pyridin- 2-yl)-methanesulfonamide, 10nM). Quantitative polymerase chain reaction (qPCR) and immunolabeling 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 showed dysfunctional integrin signaling and potassium channel function, which may contribute to podocyte death seen in Alport syndrome.

Original languageEnglish
Pages (from-to)335-347
Number of pages13
JournalJournal of Pharmacology and Experimental Therapeutics
Volume367
Issue number2
DOIs
Publication statusPublished - 1 Nov 2018

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