LOSARTAN INHIBITS MIGRATION THROUGH Hsp70 CHAPERONE IN RENAL PROXIMAL TUBULE CELLS (PTC) FROM SPONTANEOUSLY HYPERTENSIVE RATS (SHR).

COSTANTINO V.V.; BOCANEGRA MV; CACCIAMANI V; GIL LORENZO AF; BENARDÓN ME; VALLÉS PG

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Angiotensin II (AII)/AT1 receptor effects are dependent on reactive oxygen species (ROS) production. AII, induces renal injury through NADPH oxidase-dependent ROS generation. ROS function as signaling molecules contributing to migration, differentiation and cytoskeletal remodeling. Previously, we identified Hsp70 and CHIP as Nox4-interacting proteins, mediating ubiquitination and proteasomal degradation of Nox4 included within Losartan antioxidant effect on SHR PTC. Here, we evaluate Losartan (L) effect on migration, actin cytoskeletal organization and junctional-related protein in SHR PTC. Primary culture of PTC from SHR rats were stimulated with AII, treated with L or untreated (C). Live Cell Time-lapse Microscopy showed that L induces decreased cell displacement and slowed down cellular rate movement compared to C and AII PTC. Also, the cells remained attached and did not change their morphology compared to C and AII PTC. Inmunofluorescence shows actin filaments highly organized in L treated cells compared to C and AII treated cells. Furthermore, L increased the cortical E-cadherin levels. When the Hsp72 expression was silenced, L treated cells showed velocity and displacement values like C PTC. In addition, L was unable to stabilize the cytoskeleton showing an increase in misaligned actin filaments and decreased cortical E-cadherin. Western Blot, showed L increased vinculin and E-cadherin and decreased Nox4, p-ERK and p-p38 levels related to AII and C. Also, L decreased Rac1 and RhoA levels in membrane fractions, this effect was reversed in Hsp70 silenced cells. In conclusion, Losartan AT1R blockage induces actin cytoskeleton stabilization and cell migration reduction. Moreover, through Hsp72 protein knockdown, we demonstrate that the chaperone is required for the cytoskeletal integrity modulation within the effect of L in PTC from SHR. A protective role of L could be suggested avoiding tubular cell detachment and stabilizing cell junctions.