P C Baer1, S Gauer, B Wegner, R Schubert, H Geiger. 1. Department of Internal Medicine III, Division of Nephrology, J.W. Goethe University, Frankfurt/Main, Germany. P.Baer@em.uni-frankfurt.de
Abstract
AIMS: C-reactive protein (CRP) is a component of the acute-phase reaction to inflammation, severe tissue injury, and infection. Investigations have shown that CRP concentration is highly increased in the urine during acute renal graft dysfunction and, therefore, may affect tubular cell metabolism. Nevertheless, no data about the effects of CRP on human renal tubular epithelial cells are available. METHODS: Human renal distal tubular cells (DTC) were isolated immunomagnetically and cultured. Cells were stimulated with affinity chromatography pure native CRP from human ascites (10 - 0.001 microg/ml). Phosphorylation of MAP-K was assessed by Westernblot analysis. Release of RANTES and interleukin-6 was evaluated with an enzyme immunoassay. Cytotoxic effects of CRP were determined by a commercially available Live/Dead assay and MTT assay. Effects on cell proliferation were analyzed by a fluorimetric assay. RESULTS: Westernblot analysis clearly showed that CRP activates the MAP-K pathway of DTC. CRP upregulated RANTES expression of DTC in a significant and dose-dependent manner. CRP (10 microg/ml) induced a 12.3-fold upregulation, CRP 1 or 0.1 microg/ml induced a 6.3-/2.8-fold RANTES upregulation, respectively. Interleukin-6 synthesis was not influenced. Cytotoxic, proliferative or apoptotic effects were not observed at the concentrations used. CONCLUSIONS: We demonstrated an activating effect of CRP on DTC in vitro. In vivo, this effect of CRP might be part of the immune activation cascade during episodes of renal graft rejection or bacterial infections.
AIMS: C-reactive protein (CRP) is a component of the acute-phase reaction to inflammation, severe tissue injury, and infection. Investigations have shown that CRP concentration is highly increased in the urine during acute renal graft dysfunction and, therefore, may affect tubular cell metabolism. Nevertheless, no data about the effects of CRP on human renal tubular epithelial cells are available. METHODS:Human renal distal tubular cells (DTC) were isolated immunomagnetically and cultured. Cells were stimulated with affinity chromatography pure native CRP from humanascites (10 - 0.001 microg/ml). Phosphorylation of MAP-K was assessed by Westernblot analysis. Release of RANTES and interleukin-6 was evaluated with an enzyme immunoassay. Cytotoxic effects of CRP were determined by a commercially available Live/Dead assay and MTT assay. Effects on cell proliferation were analyzed by a fluorimetric assay. RESULTS: Westernblot analysis clearly showed that CRP activates the MAP-K pathway of DTC. CRP upregulated RANTES expression of DTC in a significant and dose-dependent manner. CRP (10 microg/ml) induced a 12.3-fold upregulation, CRP 1 or 0.1 microg/ml induced a 6.3-/2.8-fold RANTES upregulation, respectively. Interleukin-6 synthesis was not influenced. Cytotoxic, proliferative or apoptotic effects were not observed at the concentrations used. CONCLUSIONS: We demonstrated an activating effect of CRP on DTC in vitro. In vivo, this effect of CRP might be part of the immune activation cascade during episodes of renal graft rejection or bacterial infections.
Authors: Salim S Virani; Vijay Nambi; Ron Hoogeveen; Bruce A Wasserman; Josef Coresh; Franklyn Gonzalez; Lloyd E Chambless; Thomas H Mosley; Eric Boerwinkle; Christie M Ballantyne Journal: Eur Heart J Date: 2010-10-12 Impact factor: 29.983