A polymorphism consisting of the presence or absence of a 250-bp DNA fragment was detected within the angiotensin I-converting enzyme gene (ACE) using the endothelial ACE cDNA probe. This polymorphism was used as a marker genotype in a study involving 80 healthy subjects, whose serum ACE levels were concomitantly measured. Allele frequencies were 0.6 for the shorter allele and 0.4 for the longer allele. A marked difference in serum ACE levels was observed between subjects in each of the three ACE genotype classes. Serum immunoreactive ACE concentrations were, respectively, 2993±49, 392.6±66.8, and 494.1±883 ,g/liter, for homozygotes with the longer allele (n = 14), and heterozygotes (n = 37) and homozygotes (n = 29) with the shorter allele. The insertion/deletion polymorphism accounted for 47% of the total phenotypic variance of serum ACE, showing that the ACE gene locus is the major locus that determines serum ACE concentration. Concomitant determination of the ACE genotype will improve discrimination between normal and abnormal serum ACE values by allowing comparison with a more appropriate reference interval. (J. Clin. Invest. 1990Invest. . 86:1343Invest. -1346

No abstract

No abstract

The amino-terminal amino acid sequence and several internal peptide sequences of angiotensin I-converting enzyme (ACE; peptidyl-dipeptidase A, kininase II; EC 3.4.15. 1) purified from human kidney were used to design oligonucleotide probes. The nucleotide sequence of ACE mRNA was determined by molecular cloning of the DNA complementary to the human vascular endothelial cell ACE mRNA. The complete amino acid sequence deduced from the cDNA contains 1306 residues, beginning with a signal peptide of 29 amino acids. A highly hydrophobic sequence located near the carboxylterminal extremity of the molecule most likely constitutes the anchor to the plasma membrane. The sequence of ACE reveals a high degree of internal homology between two large domains, suggesting that the molecule resulted from a gene duplication. Each of these two domains contains short amino acid sequences identical to those located around critical residues of the active site of other metallopeptidases (thermolysin, neutral endopeptidase, and collagenase) and therefore bears a putative active site. Since earlier experiments suggested that a single Zn atom was bound per molecule of ACE, only one of the two domains should be catalytically active. The results of genomic DNA analysis with the cDNA probe are consistent with the presence of a single gene for ACE in the haploid human genome. Whereas the ACE gene is transcribed as a 4.3-kilobase mRNA in vascular endothelial cells, a 3.0-kilobase transcript was detected in the testis, where a shorter form of ACE is synthesized.Peptidyl-dipeptidase A (EC 3.4.15.1) plays an important role in blood pressure homeostasis by hydrolyzing angiotensin I, the inactive peptide released after cleavage of angiotensin by renin, into angiotensin II (1). Accordingly, this Zn metallopeptidase is designated angiotensin I-converting enzyme (ACE), although being the same enzyme as kininase II, it is also able to hydrolyze bradykinin and various other peptides (2, 3). This enzyme is a widely distributed peptidase, occurring, for example, as a membrane-bound ectoenzyme on the surface of vascular endothelial cells and renal epithelial cells and as a circulating enzyme in plasma (3-5). We report here the amino acid sequence of ACE as deduced from the nucleotide sequence of DNA complementary to the ACE mRNA.t MATERIALS AND METHODSPurification and Sequencing of ACE and Preparation of Oligodeoxyribonucleotide Probe. The cortex offresh postmortem human kidneys (600 g) was homogenized (54:100, wt/vol) in 20 mM potassium phosphate buffer (pH 8) containing 250 mM sucrose and a mixture of protease inhibitors, cells debris was discarded, and the particulate fraction was sedimented by centrifugation at 105,000 x g for 1 hr. The pellet was resuspended in 200 ml of 150 mM potassium phosphate buffer (pH 8; buffer I) and treated for 18 hr with the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS, 8 mM; Serva). The supernatant obtained after centrifugation at 105,000 x g for 1 hr was dialyzed extensively against b...

We conducted the present study to determine whether the angiotensin II type I receptor (AT,) gene might be implicated in human essential hypertension by using case-control and linkage studies. The entire coding and 3' untranslated regions of the AT, receptor gene (2.2 kb) were amplified by polymerase chain reaction and submitted to single-strand conformation polymorphism in 60 hypertensive subjects with a familial susceptibility. We identified five polymorphisms (T 573 -»C, A 1062 -*G, A" 6 6^C , G 1 5 "^T, and A' 878 -»G). However, no mutations that alter the encoded amino acid sequence were detected. A case-control study performed on white hypertensive (n=206; blood pressure, 168±16/103±9 mm Hg) and normotensive (n=298; blood pressure, 122±10/75±9 mm Hg) subjects using three of five polymorphisms showed a significant increase in allelic fre-H uman essential hypertension is thought to result from the interaction of environmental and genetic factors, with approximately 30% of the interindividual variability in blood pressure being genetically determined.1 The renin-angiotensin system is an important component of blood pressure regulation, playing roles in saltwater homeostasis and vascular tone, 2 and has been suspected to be involved in hypertension. Indeed, evidence for a genetic linkage of human essential hypertension to the angiotensinogen locus was recently obtained in an extensive collaborative study.3 However, linkage and association studies of the human renin and angiotensin I (Ang I)-converting enzyme loci have given negative results. 49Ang II receptors, which mediate the vasoconstrictive and salt-conserving actions of the renin-angiotensin system, also represent interesting candidate genes for essential hypertension. Two subtypes of cell surface

No abstract

Apelin, a peptide recently isolated from bovine stomach tissue extracts, has been identi®ed as the endogenous ligand of the human orphan APJ receptor. We established a stable Chinese hamster ovary (CHO) cell line expressing a gene encoding the rat apelin receptor fused to the enhanced green¯uorescent protein, to investigate internalization and the pharmacological pro®le of the apelin receptor. Stimulation of this receptor by the apelin fragments K17F (Lys1-Phe-Arg-Arg-Gln-Arg-Pro-ArgLeu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe17) and pE13F (pGlu5-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe17) resulted in a dose-dependent inhibition of forskolin-induced cAMP production and promoted its internalization. In contrast, the apelin fragments R10F (Arg8-Leu-Ser-His-Lys-Gly-Pro-Met-ProPhe17) and G5F (Gly13-Pro-Met-Pro-Phe17) were inactive. The physiological role of apelin and its receptor was then investigated by showing for the ®rst time in rodent brain: (i) detection of apelin neurons in the supraoptic and paraventricular nuclei by immunohistochemistry with a speci®c polyclonal anti-apelin K17F antibody; (ii) detection of apelin receptor mRNA in supraoptic vasopressinergic neurons by in situ hybridization and immunohistochemistry; and (iii) a decrease in vasopressin release following intracerebroventricular injection of K17F, or pE13F, but not R10F. Thus, apelin locally synthesized in the supraoptic nucleus could exert a direct inhibitory action on vasopressinergic neuron activity via the apelin receptors synthesized in these cells. Furthermore, central injection of pE13F signi®cantly decreased water intake in dehydrated normotensive rats but did not affect blood pressure. Together, these results suggest that neuronal apelin plays an important role in the central control of body¯uid homeostasis. Keywords: arterial blood pressure, drinking behaviour, internalization, second messenger, vasopressin release.

This is the first study directly demonstrating hypoxia in advanced human atherosclerosis and its correlation with the presence of macrophages and the expression of HIF and VEGF. Also, the HIF pathway was associated with lesion progression and angiogenesis, suggesting its involvement in the response to hypoxia and the regulation of human intraplaque angiogenesis.