RhoA and MAPK signal transduction pathways regulate NHE1-dependent proximal tubule cell apoptosis after mechanical stretch.

Autor:	Bocanegra V; Instituto de Medicina y Biología Experimental de Cuyo-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; and., Gil Lorenzo AF; Instituto de Medicina y Biología Experimental de Cuyo-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; and., Cacciamani V; Área de Fisiología Patológica, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina., Benardón ME; Área de Fisiología Patológica, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina., Costantino VV; Instituto de Medicina y Biología Experimental de Cuyo-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; and., Vallés PG; Instituto de Medicina y Biología Experimental de Cuyo-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; and Área de Fisiología Patológica, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina pvalles@fcm.uncu.edu.ar.
Jazyk:	angličtina
Zdroj:	American journal of physiology. Renal physiology [Am J Physiol Renal Physiol] 2014 Oct 01; Vol. 307 (7), pp. F881-9. Date of Electronic Publication: 2014 Jul 30.
DOI:	10.1152/ajprenal.00232.2014
Abstrakt:	Mechanical deformation after congenital ureteral obstruction is traduced into biochemical signals leading to tubular atrophy due to epithelial cell apoptosis. We investigated whether Na(+)/H(+) exchanger 1 (NHE1) could be responsible for HK-2 cell apoptosis induction in response to mechanical stretch through its ability to function as a control point of RhoA and MAPK signaling pathways. When mechanical stretch was applied to HK-2 cells, cell apoptosis was associated with diminished NHE1 expression and RhoA activation. The RhoA signaling pathway was confirmed to be upstream from the MAPK cascade when HK-2 cells were transfected with the active RhoA-V14 mutant, showing higher ERK1/2 expression and decreased p38 activation associated with NHE1 downregulation. NHE1 participation in apoptosis induction was confirmed by specific small interfering RNA NHE1 showing caspase-3 activation and decreased Bcl-2 expression. The decreased NHE1 expression was correlated with abnormal NHE1 activity addressed by intracellular pH measurements. These results demonstrate that mitochondrial proximal tubule cell apoptosis in response to mechanical stretch is orchestrated by signaling pathways initiated by the small GTPase RhoA and followed by the opposing effects of ERK1/2 and p38 MAPK phosphorylation, regulating NHE1 decreased expression and activity. (Copyright © 2014 the American Physiological Society.)
Databáze:	MEDLINE
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