Effect of Endothelin-1 on the Proliferation and Activity of HOS Cells

Endothelin-1이 HOS 세포의 증식과 활성에 미치는 영향

Endothelin-1 (ET-1) is a recently discovered potent vasoconstrictive peptide. It was first identified in vascular endothelial cells. ET-1 is a 21-amino acid peptide and elicits systemic effects such as stimulation of the production of atrial natriuretic peptide and release of aldosterone and corticosterone. In this study, to examine the role of ET-1 in the bone metabolism, effect of ET-1 on the proliferation and activity of osteoblastic cells was studied using HOS cells as osteoblast model. ET-1 dose-dependently increased the cell proliferation as determined by cell counting and MTT reduction assay after 48hr treatment. Alkaline phosphatase activity was inhibited by ET-1 and showed significant inhibition by 50 and 100 nM ET-1. ET-1 increased NBT reduction by HOS cells dose-dependently showing that ET-1 may increase the superoxide production by osteoblasts. Nitrite concentration in the media of HOS cell culture without cytokine stimulation was negligible and unaffected by ET-1 after 48hr treatment. Finally, after collection and concentration of conditioned media, gelatinase activity produced by HOS cells was determined by zymography. HOS cells can produce and secrete the gelatinase (gelatinase A type as determined by molecular weight of about 65,000) into culture media, however, ET-1 had no effect on the gelatinase activity. These findings suggest that ET-1 may have diverse effects on the proliferation and differentiation of osteoblasts, therefore, it may play an important role in bone metabolism.