NDT Advance Access originally published online on June 21, 2008
Nephrology Dialysis Transplantation 2008 23(11):3403-3411; doi:10.1093/ndt/gfn333
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The mitogen-activated protein kinase Erk5 mediates human mesangial cell activation
1 Instituto Reina Sofía de Investigación Nefrológica, Departamento de Fisiología y Farmacología, Universidad de Salamanca 2 Red de Investigación en Enfermedades Renales (RedinRen), Instituto Carlos III de Investigación, Ministerio de Sanidad y Consumo 3 Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas-Universidad de Salamanca 4 Servicio de Urología, Hospital Universitario de Salamanca, Salamanca, Spain
Correspondence and offprint requests to: Alicia Rodríguez-Barbero, Departamento de Fisiología y Farmacología, Universidad de Salamanca, Campus Miguel de Unamuno, Edificio Departamental, 37007 Salamanca, Spain. Tel: +34-923-294472; Fax: +34-923-294669; E-mail: barberoa{at}usal.es
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Abstract |
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Background. Mesangial activation occurs in many forms of renal disease that progress to renal failure. Mitogen-activated protein kinases (MAPKs) are important mediators involved in the intracellular network of interacting proteins that transduce extracellular stimuli to intracellular responses. The extracellular signal-regulated kinases 5 (Erk5) MAPK pathway has been involved in regulating several cellular responses. Thus, we examined the expression of Erk5 in human renal tissue and the function of Erk5 in cultured human mesangial cells.
Methods. Erk5 was visualized in human renal tissue by immunohistochemistry and in mesangial cells by immunofluorescence microscopy using the anti-Erk5 C-terminus antibody. Erk5 expression and activation, and collagen I expression were determined by western blot. To generate a dominant-negative form of the Erk5 in human mesangial cells, an EcoRI fragment from wild-type pCEFL-HA-Erk5 was subcloned into the EcoRI site of pCDNA3. Cell proliferation was analysed by an MTT-based assay. Cell contraction was analysed by studying the changes in the planar cell surface area.
Results. Erk5 was expressed in the kidney, mainly localized at the glomerular mesangium. In cultured human mesangial cells, Erk5 was activated by foetal calf serum (FCS), high glucose, endothelin-1, platelet-activating factor (PAF), epidermal growth factor (EGF) and transforming growth factor beta-1 (TGF-β1). The expression of a dominant-negative form of Erk5 in human mesangial cells resulted in a significant decrease in proliferation, EGF-induced cell contraction and TGF-β1-induced collagen I expression.
Conclusions. These results suggest that Erk5 is involved in agonist-induced mesangial cell contraction, proliferation and ECM accumulation and point to a multifunctional role of Erk5 in the pathophysiology of glomerular mesangial cells.
Keywords: cell contraction; cell proliferation; Erk5 MAPK; extracellular matrix; mesangial cells
Received for publication: 15.11.07
Accepted in revised form: 21. 5.08