Role Of Angiotensin I-converting Enzyme Research Articles

The role of angiotensin I-converting enzyme gene polymorphism and global DNA methylation in the negative associations between urine di-(2-ethylhexyl) phthalate metabolites and serum adiponectin in a young Taiwanese population

BackgroundAdiponectin is a key protein produced in adipose tissue, with crucial involvement in multiple metabolic processes. Di-(2-ethylhexyl) phthalate (DEHP), one of the phthalate compounds used as a plasticizer, has been shown to decrease adiponectin levels in vitro and in vivo studies. However, the role of angiotensin I-converting enzyme (ACE) gene polymorphism and epigenetic changes in the relationship between DEHP exposure and adiponectin levels is not well understood.MethodsThis study examined the correlation between urine levels of DEHP metabolite, epigenetic marker 5mdC/dG, ACE gene phenotypes, and adiponectin levels in a sample of 699 individuals aged 12–30 from Taiwan.ResultsResults showed a positive relationship between mono-2-ethylhexyl phthalate (MEHP) and 5mdC/dG, and a negative association between both MEHP and 5mdC/dG with adiponectin. The study found that the inverse relationship between MEHP and adiponectin was stronger when levels of 5mdC/dG were above the median. This was supported by differential unstandardized regression coefficients (− 0.095 vs. − 0.049, P value for interaction = 0.038)). Subgroup analysis also showed a negative correlation between MEHP and adiponectin in individuals with the I/I ACE genotype, but not in those with other genotypes, although the P value for interaction was borderline significant (0.06). The structural equation model analysis indicated that MEHP has a direct inverse effect on adiponectin and an indirect effect via 5mdC/dG.ConclusionsIn this young Taiwanese population, our findings suggest that urine MEHP levels are negatively correlated with serum adiponectin levels, and epigenetic modifications may play a role in this association. Further study is needed to validate these results and determine causality.

ACE activity in blood and brain axis in an animal model for schizophrenia: Effects of dopaminergic manipulation with antipsychotics and psychostimulants

Objectives: Angiotensin I-converting enzyme (ACE) was initially correlated with schizophrenia (SCZ) in studies showing a correlation of ACE increased enzyme activity with memory impairments. Possible role for ACE in SCZ was also suggested by ACE activity interaction with dopaminergic mechanisms to modulate abnormalities of sensorimotor gating. In addition, we have demonstrated higher ACE activity in blood of SCZ subjects, its implication in cognitive performance in SCZ and its power as a predictor for SCZ diagnosis.Methods: ACE activity was determined in the serum and in selected brain regions of an animal model presenting SCZ-like behaviour, before and after the treatment with typical and atypical antipsychotics, and also in the serum of animals receiving the psychostimulants amphetamine/lisdexamphetamine.Results: Dopaminergic manipulations with antipsychotics and psychostimulants influenced the ACE activity, but with no correlation with the animal blood pressure.Conclusions: The validity of measuring ACE activity in animal blood to predict activity in the CNS, as well as the lack of correlation between the activity and blood pressure, before and after the treatment with antipsychotics, were confirmed here. Correlations of the present findings with data from clinical studies also strengthen the value of this animal model for studying several aspects of SCZ.

Cell Proliferation and Migration Induced by Angiotensin-II is Mediated by ACE

We have demonstrated that the Angiotensin I Converting Enzyme (ACE) acts as a membrane receptor for Angiotensin II (AngII). Upon binding to ACE with high affinity, AngII activates a signaling cascade that generates inositol 1,4,5-triphosphate (InsP3), culminating in intracellular Ca2+ increase. The goal of this work was to investigate cellular function that AngII plays through ACE activation. For that, we used CHO-ACE, CHO-AT1 and melanoma cell line (Tm-5), as well as, confocal microscopy, immunofluorescence, western blotting, small interfering RNA (siRNA) and BrDU assay. We found that AngII binds to ACE and this complex is internalized through clathrin, to trigger preferential nucleoplasmic Ca2+ increase. Since nuclear Ca2+ is known to regulate cell growth, we then investigated whether the proliferative response induced by AngII is mediated by ACE activation. We verified that silencing either ACE or clathrin reduced cell proliferation stimulated by AngII by 33% or 71% respectively, compared to control (p<0.001). In melanoma cell line (Tm-5), that was known to expresses mainly ACE instead of the classical AngII receptor, the AT1, AngII increased cell migration by 75.7 ± 2% compared to control condition (p<0.05). This data correlated with reduced focal adhesion formation induced by AngII in the same cell line (154 ± 23.9 a.u. for control vs, 54.9 ± 9.8 a.u. for AngII, p<0.05), Together, these results indicate a new role for ACE in cell proliferation and migration induced by AngII. Moreover, these findings point ACE signaling as a novel therapeutic target for cancer treatment.

Novel Insights in Pharmacogenetics of Drug Response in Parkinson‘s Disease

receptor DRD2 gene, the dopamine transporter (DAT ) gene and μ1 opioid receptor (OPRM1) gene. Motor fluctuations have been associated with a DRD2 gene polymorphism [6], although other studies could not replicate this finding. Conflicting results have been reported concerning the relationship between the occurrence of drug-induced hallucinations in PD and genetic polymorphisms. While some studies demonstrated significant associations between hallucinations and polymorphisms in the DAT gene, the cholecystokinin (CCK ) gene and the apolipoprotein E (APOE) gene, others failed to replicate these results. Associations were found between sleep attacks without warning signs and a polymorphism in the DRD4 gene, the preprohypocretin (HCRT ) gene, the DRD2 gene and the catechol-O-methyl transferase (COMT ) gene. In addition, similar findings were found in recent studies investigating polymorphisms in genes encoding dopamine D 2 and D 3 receptors [7–9] and COMT [10]. Lin and colleagues investigated the role of angiotensin I-converting enzyme in levodopa response [11]. They demonstrated that patients with a homozygote (ins/ins) genotype of the ACE gene had a 2.5-times higher risk of levodopa-induced psychosis, a disabling complication, particularly in the later stage of the disease. The role of angiotensin I-converting enzyme in the development of levodopa-induced psychosis is relatively unexplored. It is necessary to reproduce this study in independent cohorts. We concluded that, in comparison with other subject areas such as psychiatry [12], relatively few efforts have been made to investigate the role of pharmacogenetics in the individual response to anti-PD drugs. The focus of pharmacogenetic studies in patients with PD was mainly on genes coding for drug receptors, drug transporters and synaptic drug-metabolizing enzymes (pharmacodynamics). The pharmacogenetic studies in both PD and psychiatry did not, for the most part, Parkinson’s disease (PD) is characterized by brady kinesia, rigidity and tremor, and is the result of degeneration of dopaminergic neurones in the substantia nigra pars compacta. PD has a prevalence of approximately 0.5–1% in persons of 65–69 years, rising to 1–3% among persons of 80 years and older [1]. Twin studies suggest a limited role for genetic factors in the etiology of PD, perhaps most prominently in early-onset forms [2]. The etiology of the common late-onset forms of PD remains largely to be elucidated. Anti-PD drugs, such as levodopa and the direct-acting dopamine agonists, are effective in reducing the motor symptoms of PD. However, these drugs are also associated with the development of motor complications, such as levodopainduced dyskinesia (LID), response fluctuations and side effects, such as hallucinations and excessive daytime sleepiness. In clinical practice, a large interindividual variability in drug response has been noticed. For example, up to 45% of levodopa users develop LID within 5 years, while others remain free of LID for many years [3]. Up to 25% of users of dopaminergic drugs develop hallucinations, whereas others do not [4].

Association of Angiotensin I-Converting Enzyme Gene Insertion/Deletion Polymorphism and IgA Nephropathy: A Meta-Analysis

Background/Aims: The angiotensin I-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been extensively examined for the association with immunoglobulin A (IgA) nephropathy (IgAN), however, conflicting results have occurred. We performed a meta-analysis to evaluate the association of ACE I/D polymorphism with IgAN in different ethnic groups. Methods: 11 studies testing the association between ACE I/D polymorphism and IgAN susceptibility, and 9 studies testing the association of ACE I/D with IgAN progression were used in this analysis. The overall odds ratio (OR) was estimated by a fixed or random effect model. Results: The overall OR for the risk of susceptibility and progression of IgAN in Asians for the DD genotype is 2.37 (95% CI 1.04–5.41) and 1.75 (95% CI 1.24–2.56). The overall OR for the D allele in Asians also showed a similar magnitude, though without statistical significance (p = 0.09, p = 0.13, respectively). In Caucasians, both the DD genotype and D allele were associated with IgAN progression (OR 1.90, 1.61, respectively), but not IgAN susceptibility (p = 0.30, p = 0.41, respectively). Conclusion: Our findings support the notion that ACE I/D polymorphism is associated with IgAN. Meanwhile, the role of ACE I/D polymorphism in Asians is different from that of Caucasians.

Association between angiotensin I-converting enzyme gene insertion/deletion polymorphism and mitral valve prolapse syndrome

Background Some studies have reported that patients with mitral valve prolapse syndrome (MVPS) also have a disorder in the autonomic or neuroendocrine function, which can cause a host of related symptoms. A potential role of the renin-angiotensin system in the pathogenesis of MVPS has been addressed. However, the role of angiotensin I-converting enzyme (ACE) genetic variant in MVPS has not been studied. We therefore performed a case-control study investigating the possible relation between ACE gene polymorphisms and MVPS in Taiwan Chinese. Methods We studied 100 patients with MVPS diagnosed by echocardiography and 100 age- and sex-matched normal control patients. ACE gene insertion/deletion (I/D), A-240T, and G2350A polymorphisms were identified by polymerase chain reaction-based restriction analysis. Results There was a significant difference in the distribution of ACE I/D genotypes ( P = .003) and allelic frequencies ( P = .001) between MVPS cases and control patients. An odds ratio for the risk of MVPS associated with the ACE II genotype was 2.14 (95% CI 1.20-3.80 ). An odds ratio for the risk of MVPS associated with ACE I allele was 1.96 (95% CI 1.30-2.97). The A-240T and G2350A polymorphisms of the ACE gene showed no association with MVPS ( P = .20, P = .13, respectively). Conclusions This study showed that patients with MVPS have a higher frequency of ACE II genotype, which supports a role of the ACE I/D gene polymorphism in determining the risk of MVPS among the Chinese population in Taiwan. (Am Heart J 2003;145:169-73.)

Genetic variation in the renin-angiotensin system and athletic performance.

The D allele at the angiotensin-I-converting enzyme (ACE)-insertion/deletion polymorphism has been associated with an increased risk of developing several pathological processes, such as coronary heart disease and ventricular hypertrophy. Individuals with the DD genotype show a significantly increased left-ventricular mass in response to physical training, compared to the II genotype (which would be associated with the lowest plasma ACE levels) and the ID genotype. The II genotype has been linked to a greater anabolic response. In accordance with a role for ACE in the response to rigorous physical training, a higher frequency of the I allele has been reported to exist among elite rowers and high-altitude mountaineers. Sixty elite (professional) athletes (25 cyclists, 20 long-distance runners, and 15 handball players), and 400 healthy controls were genotyped for the DNA polymorphisms of the ACE, angiotensinogen (Ang) and angiotensin receptor type 1 (AT1) genes. Plasma ACE levels showed a strong correlation with the I/D genotype in our population. The I-allele occurred at a significantly higher frequency in athletes compared to controls (P = 0.0009). Gene and genotype frequencies for the Ang and AT1 polymorphisms did not differ between athletes and controls. Since the frequency of the ACE I allele was significantly increased among our elite athletes, we conclude that the ACE polymorphism represents a genetic factor that contributes to the development of an elite athlete.

A novel peptide-processing activity of insect peptidyl-dipeptidase A (angiotensin I-converting enzyme): the hydrolysis of lysyl-arginine and arginyl-arginine from the C-terminus of an insect prohormone peptide.

Insect peptidyl-dipeptidase A [angiotensin I-converting enzyme (ACE)] is a soluble single-domain peptidyl-dipeptidase that has many properties in common with the C-domain of mammalian somatic ACE and with the single-domain mammalian germinal ACE. Mammalian somatic ACE is important in blood homoeostasis, but the role of ACE in insects is not known. Immunocytochemistry has been used to localize ACE in the neuroendocrine system of the locust, Locusta migratoria. Staining was observed in five groups of neurosecretory cells in the brain and suboesophageal ganglion, in the nervi corpori cardiaci, the storage part of the corpora cardiaca and in the nervi corpori allati. In three groups of neurosecretory cells, ACE co-localized with locustamyotropins, suggesting a possible role for the enzyme in the metabolism of these neuropeptides. We demonstrate in vitro a novel activity of ACE that removes pairs of basic amino acid residues from a locustamyotropin peptide extended at the C-terminus with either Gly-Lys-Arg or Gly-Arg-Arg, corresponding to a consensus recognition sequence for endoproteolysis of prohormone proteins by prohormone convertases. The low Km and high kcat values (Km 7.3 and 5.0 microM, kcat 226 and 207 s-1 for the hydrolysis of Phe-Ser-Pro-Arg-Leu-Gly-Lys-Arg and Phe-Ser-Pro-Arg-Leu-Gly-Arg-Arg, respectively) obtained for the hydrolysis of these two peptides by insect ACE means that these peptides, along with mammalian bradykinin, are the most favoured in vitro ACE substrates so far identified. The discovery of this in vitro prohormone-processing activity of insect ACE provides a possible explanation for the intracellular co-localization of the enzyme with locustamyotropin peptides, and provides evidence for a new role for ACE in the biosynthesis of peptide hormones and transmitters.

Angiotensin I-converting enzyme (ACE): estimation of DNA haplotypes in unrelated individuals using denaturing gradient gel blots

The angiotensin I-converting enzyme (ACE) gene (17q23) is a candidate gene for essential hypertension and related diseases, but investigation of its role in human pathology is hampered by a lack of identified polymorphisms. Currently, a 287-bp insertion/deletion (I/D) RFLP in intron 16 represents the only one known. Additional polymorphisms for the ACE gene would make most families informative for linkage studies and would allow haplotypes to be assigned in association studies. To increase the information provided by the ACE gene, we used a sensitive screening technique, denaturing gradient gel electrophoresis (DGGE) blots, to identify polymorphisms and combined this with gene counting to identify haplotypes. Five independent polymorphisms, restriction fragment melting polymorphisms (RFMPs), were identified by four probes (encompassing half of the ACE cDNA) in digests produced by three restriction enzymes (DdeI, RsaI, and AluI). One RFMP has three alleles while the others have two alleles. In a sample of 67 unrelated control subjects, minor allele frequencies ranged from 0.12 to 0.49. A significant level of linkage disequilibrium was found for all pairs of markers. The four most informative RFMPs, taken in combination, define 24 potential haplotypes. Based on gene counting, 11 of the 24 are rare or nonexistent in this population, and the estimated heterozygosity of the remaining 13 haplotypes approaches 80%. Under these conditions for the ACE locus, phase-unknown genotypes could be assigned to haplotype pairs in unrelated subjects with reasonable certainty. Thus, using DGGE blot technique for identifying numerous DNA polymorphisms in a candidate locus, in combination with gene counting, one can often identify DNA haplotypes for both related and unrelated study subjects at a candidate locus. These markers in the ACE gene should be useful for clinical and epidemiologic studies of the role of ACE in human disease.

Effects of smokeless tobacco on chemically transformed hamster oral keratinocytes: role of angiotensin I-converting enzyme.

The purpose of this study was to determine whether exposure of chemically transformed golden Syrian hamster oral epidermoid carcinoma cell (HCPC-1) cultures to smokeless tobacco extract (STE) is associated with a decrease in specific angiotensin I-converting enzyme (ACE) activity and whether this decrease potentiates bradykinin-induced cell growth. We found that STE induced a significant concentration- and time-dependent decrease in ACE activity in cultured HCPC-1 cells (P < 0.05). STE alone had no significant effect on cell number. Bradykinin alone induced a slight, but significant, increase in cell number (P < 0.05). These effects were significantly potentiated by STE (P < 0.01). We conclude that STE potentiates bradykinin-induced HCPC-1 cell growth, in part by attenuating specific ACE activity in these cells.