Atorvastatin Increases Endoglin, SMAD2, Phosphorylated SMAD2/3 and eNOS Expression in ApoE/LDLR Double Knockout Mice

Endoglin is a homodimeric transmembrane glycoprotein that has been demonstrated to affect transforming growth factor beta (TGF-beta) signaling and endothelial nitric oxide synthase (eNOS) expression by affecting SMAD proteins in vitro. Thus, in this study we stepped forward to elucidate whether endoglin is co-expressed with SMAD2, phosphorylated SMAD2/3 proteins and eNOS in vivo in atherosclerotic lesions in ApoE/LDLR double knockout mice. In addition, we sought whether endoglin expression as well as the expression of SMAD2, phosphorylated SMAD2/3 and eNOS is affected by atorvastatin treatment.

Two-month-old female ApoE/LDLR double knockout mice were divided into two groups. The control group was fed with the western type diet whereas in the atorvastatin group, atorvastatin at dose 100 mg/kg per day was added to the same diet. Immunohistochemical and western blot analysis of endoglin, SMAD2, phosphorylated SMAD2/3 and eNOS expressions in aorta were performed.

The biochemical analysis showed that administration of atorvastatin significantly decreased level of total cholesterol, VLDL, LDL, TAG, and significantly increased level of HDL cholesterol. Fluorescence immunohistochemistry showed endoglin co-expression with SMAD2, phosphorylated SMAD2/3 and eNOS in aortic endothelium covering atherosclerotic lesions in both control and atorvastatin treated mice. Western blot analysis demonstrated that atorvastatin significantly increased expression of endoglin, SMAD2, phosphorylated SMAD2/3, and eNOS in mice aorta.

These findings suggest, that endoglin might be interesting marker of endothelial dysfunction and/or atherogenesis which is upregulated by statins implicating potential beneficial role of endoglin and its pathway in atherosclerosis.