Abstract-Essential hypertension has a genetic basis. Accumulating evidence, including findings of elevation of arterial blood pressure in mice lacking the endothelial nitric oxide synthase (eNOS) gene, strongly suggests that alteration in NO metabolism is implicated in hypertension. There are, however, no reports indicating that polymorphism in the eNOS gene is associated with essential hypertension. We have identified a missense variant, Glu298Asp, in exon 7 of the eNOS gene and demonstrated that it is associated with both coronary spastic angina and myocardial infarction. To explore the genetic involvement of the eNOS gene in essential hypertension, we examined the possible association between essential hypertension and several polymorphisms including the Glu298Asp variant, variable number tandem repeats in intron 4 (eNOS4b/4a), and two polymorphisms in introns 18 and 23. We performed a large-scale study of genetic association using two independent populations from Kyoto (nϭ458; 240 normotensive versus 218 hypertensive subjects) and Kumamoto (nϭ421; 223 normotensive versus 187 hypertensive subjects), Japan. In both groups, a new coding variant, Glu298Asp, showed a strong association with essential hypertension (Kyoto: odds ratio, 2.3 [95% confidence interval, 1.4 to 3.9]; Kumamoto: odds ratio, 2.4 [95% confidence interval, 1.4 to 4.0]). The allele frequencies of 298Asp in hypertensive subjects were significantly higher than those in normotensive subjects in both groups (Kyoto: 0.103 versus 0.050, PϽ0.0017; Kumamoto: 0.120 versus 0.058, PϽ0.0013, respectively). No such disequilibrium between genotypes was significantly associated with any other polymorphisms we examined; the Glu298Asp variant was also not linked to any other polymorphisms. In conclusion, the Glu298Asp missense variant was significantly associated with essential hypertension, which suggests that it is a genetic susceptibility factor for essential hypertension.(Hypertension. 1998;32:3-8.)Key Words: genes Ⅲ nitric oxide synthase Ⅲ hypertension, essential Ⅲ polymorphism Ⅲ genetics W ith a genetic contribution of from 25% to 60%, human essential hypertension has a genetic basis. Among persons younger than age 50 years, essential hypertension occurs 3.8 times more often in those having two or more first-degree relatives who developed high blood pressure before age 55.1 NO synthesis by the vascular endothelium is important for the regulation of vasodilator tone and the control of blood pressure in humans.2 A recent study using mice with disrupted eNOS gene revealed that eNOS function is required for vascular and hemodynamic responses to acetylcholine and that the disruption of the eNOS gene leads to hypertension. 3 Moreover, recent reports demonstrate that whole-body NO production in patients with essential hypertension is diminished under basal conditions, as established by measurement of urinary and plasma nitrate. 4 In addition, the offspring of hypertensive patients exhibit a reduced response to acetylcholine linked to a defect in the NO pathway.5...

We recently reported that a mutation (-786T-->C) in the promoter region of the endothelial nitric oxide synthase (eNOS) gene reduced transcription of the gene and was strongly associated with coronary spastic angina and myocardial infarction. To elucidate the molecular mechanism for the reduced eNOS gene transcription, we have now purified a protein that specifically binds to the mutant allele in nuclear extracts from HeLa cells. The purified protein was identical to replication protein A1 (RPA1), known as a single-stranded DNA binding protein essential for DNA repair, replication and recombination. In human umbilical vein endothelial cells, inhibition of RPA1 expression using antisense oligonucleotide restored transcription driven by the mutated promoter sequence, whereas, conversely, overexpression of RPA1 further reduced it. RPA1 was similarly detected in placenta and eNOS mRNA levels in placentas carrying the -786T-->C mutation were significantly lower than in placentas without it. The functional importance of the diminished eNOS expression was revealed by the finding that serum nitrite/nitrate levels among individuals carrying the -786T-->C mutation were significantly lower than among those without the mutation. RPA1 thus apparently functions as a repressor protein in the -786T-->C mutation-related reduction of eNOS gene transcription associated with the development of coronary artery disease.

These results show that CT-1 secreted from cardiac nonmyocytes is significantly involved in the hypertrophic changes of cardiac myocytes in the coculture and suggest that CT-1 is an important local regulator in the process of cardiac hypertrophy.

A small GTPase, Rho, participates in agonist-induced cytoskeletal organization and gene expression in many cell types including cardiac myocytes. However, little is known about the functions of Rho's downstream targets in cardiac myocytes. We examined the role of ROCK, a downstream target of Rho, in ET-1-induced hypertrophic response. Y27632, a selective ROCK inhibitor, inhibited ET-1-induced increases in natriuretic peptide production, cell size, protein synthesis, and myofibrillar organization. In addition, a dominant-negative mutant of p160ROCK suppressed ET-1-induced transcription of the BNP gene. These findings suggest that the Rho/ROCK pathway is an important component of ET-1-induced hypertrophic signals in cardiac myocytes.z 1999 Federation of European Biochemical Societies.

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