Androgens inhibit tumor necrosis factor-α-induced cell adhesion and promote tube formation of human coronary artery endothelial cells

Endothelial cells contribute to the function and integrity of the vascular wall, and a functional aberration may lead to atherogenesis. There is increasing evidence on the atheroprotective role of androgens. Therefore, we studied the effect of the androgens - testosterone and dihydrotestosterone - and estradiol on human coronary artery endothelial cell (HCAEC) function. We found by MTT assay that testosterone is not cytotoxic and enhances HCAEC proliferation. The effect of testosterone (10-50 nM), dihydrotestosterone (5-50 nM), and estradiol (0.1-0.4 nM) on the adhesion of tumor necrosis factor-α (TNF-α)-stimulated HCAECs was determined at different time points (12-96 h) by assessing their binding with human monocytic THP-1 cells. In addition, the expression of adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1), was determined by ELISA and Western blot analysis. Both testosterone and dihydrotestosterone attenuated cell adhesion and the expression of VCAM-1 and ICAM-1 in a dose- and time-dependent manner. Furthermore, androgen treatment for a longer duration inhibited cell migration, as demonstrated by wound-healing assay, and promoted tube formation on a Matrigel. Western blot analysis demonstrated that the expression of phosphorylated endothelial nitric oxide synthase (eNOS) increased, whereas that of inducible nitric oxide synthase (iNOS) decreased following the 96-h steroid treatment of TNF-α-stimulated HCAECs. Our findings suggest that androgens modulate endothelial cell functions by suppressing the inflammatory process and enhancing wound-healing and regenerative angiogenesis, possibly through an androgen receptor (AR)-dependent mechanism.