The role of hypertension-related gene in aortic vascular smooth muscle cells from mice and rats

Objective To study the role of hypertension-related gene (HRG-1) in cardiov ascular disease. Methods The expression of HRG-1 was analyzed with RT-PCR and Northern blott ing. Vascular smooth muscle cell (VSMC) proliferation was measured with H-3 -TdR incorporation and was confirmed with histological analysis. Results Northern blot analysis showed that HRG-1 mRNA was expressed not onl y in VSMC, but also in various rat tissues (heart, brain, lung, kidney, and liver). In addition, the expression of HRG-1 mRNA in heart, brain, kidney and liver of spontaneously hypertensive rat (SHR) was lower than that in th e same tissues of Wistar-Kyotorat (WKY). Semi-quantitative RT-PCR and histo logical analysis showed that the expression of HRG-1 mRNA in ApoE-knockout mice and in animal models of restenosis was decreased and neointimal format ion was observed in both models. ET, All, and IL-1 stimulating VSMC prolife ration reduced the expression of HRG-1 mRNA of VSMC. Atrial natriuretic fac tor (ANF), calcitonin gene-related peptide and adrenomedullin, inhibited VS MC proliferation and elevated the expression of HRG-1 mRNA. These effects c ould be blocked or attenuated by their corresponding antagonists or antibod ies. Conclusion HRG-1 is a gene related to VSMC proliferation. It may play an im portant role in several occlusive cardiovascular diseases including atheros clerosis, restenosis and hypertension.