Angiotensin II disrupts the cytoskeletal architecture of human urine-derived podocytes and results in activation of the renin-angiotensin system

Abstract

High blood pressure is one of the major public health problems which causes severe disorders in several tissues including the human kidney. One of the most important signaling pathways associated with the regulation of blood pressure is the renin-angiotensin system (RAS), with its main mediator angiotensin II (ANGII). Elevated levels of circulating and intracellular ANGII and aldosterone lead to pro-fibrotic, -inflammatory and -hypertrophic milieu that causes remodelling and dysfunction in cardiovascular and renal tissues. Furthermore, ANGII has been recognized as major risk factor for the induction of apoptosis in podocytes, ultimately leading to chronic kidney disease (CDK). In the past, disease modeling of kidney-associated malignancies was extremely difficult, as the derivation of kidney originated cells is very challenging. Here we describe a differentiation protocol for reproducible differentiation of SIX2-positive urine derived renal progenitor cells (UdRPCs) into mature podocytes bearing typical foot processes. The UdRPCs-derived podocytes show the ability to execute Albumin endocytosis and the activation of the renin-angiotensin system by being responsive to ANGII stimulation. Our data reveals the ANGII dependent downregulation of NPHS1 and SYNPO, resulting in the disruption of the complex podocyte cytoskeletal architecture, as shown by immunofluorescence-based detection of -ACTININ. In the present manuscript we confirm and propose UdRPCs as a unique cell type useful for studying nephrogenesis and associated diseases. Furthermore, the responsiveness of UdRPCs-derived podocytes to ANGII implies potential applications in nephrotoxicity studies and drug screening.