Resumen de Endoglin co-expression with eNOS, SMAD2 and phosphorylated SMAD2/3 in normocholesterolemic and hypercholesterolemic mice: an immunohistochemical study

Petr Nachtigal, Lenka Vec(er(ová, Nada Pospisilova, Stanislav Micuda, Eva Brcakova, Elena Navarro Hernandez, Katerina Pospechova, Vladimir Semecky

• Summary. Endoglin, a homodimeric transmembrane glycoprotein, is a part of the transforming growth factor-ß (TGF-ß) receptor cascade. It has been demonstrated that endoglin can affect TGF-ß signaling and eNOS expression by affecting SMAD proteins in vitro. We planned to go one step forward and evaluate whether endoglin is co-expressed with SMAD2, phosphorylated SMAD2/3 protein and eNOS in endothelium of normocholesterolemic C57BL/6J mice, and in advanced atherosclerotic lesions in hypercholesterolemic apoE/LDLr-deficient mice by means of fluorescence immunohistochemistry.

  Female C57BL/6J mice were fed with a chow diet (standard laboratory diet) for 12 weeks after weaning (at the age of 4 weeks). Two-month-old female apoE/LDLr-deficient mice were fed the western type diet (atherogenic diet) containing 21% fat (11% saturated fat) and 0.15% cholesterol for 2 months. Immunohisto-chemical analysis of endoglin, SMAD2, phosphorylated SMAD2/3 and eNOS expression was performed in mice aortic sinus.

  Immunohistochemical analysis showed the expression of endoglin in intact endothelium in both C57BL/6J and apoE/LDLr-deficient mice and in endothelium covering the atherosclerotic lesion in apoE/LDLr-deficient mice. Fluorescence immunohisto-chemistry revealed co-expression of endoglin with SMAD2, phosphorylated SMAD2/3 and eNOS in intact aortic endothelium in C57BL/6J mice. Moreover, strong co-localization of endoglin, SMAD2, phosphorylated SMAD2/3 and eNOS was also detected in endothelium covering atherosclerotic lesions in apoE/LDLr-deficient mice.

  In conclusion, we suggest that endoglin, SMAD2, phosphorylated SMAD2/3 and eNOS may be important in vessel endothelium homeostasis underlying their role in atherogenesis. Histol Histopathol 24, 1499-1506 (2009)