Stretch-induced regulation of angiotensinogen gene expression in cardiac myocytes and fibroblasts: opposing roles of JNK1/2 and p38alpha MAP kinases

The cardiac renin-angiotensin system (RAS) has been implicated in mediating myocyte hypertrophy, remodeling, and fibroblast proliferation in the hemodynamically overloaded heart. However, the intracellular signaling mechanisms responsible for regulation of angiotensinogen (Ao), a substrate of the RAS system, are largely unknown. Here we report the identification of JNK1/2 as a negative, and p38α as a major positive regulator of Ao gene expression. Isolated neonatal rat ventricular myocytes (NRVM) and fibroblasts (NRFB) plated on deformable membranes coated with collagen IV, were exposed to 20% equiaxial static-stretch (0-24 h). Mechanical stretch initially depressed Ao gene expression (4 h), whereas after 8 h, Ao gene expression increased in a time-dependent manner. Blockade of JNK1/2 with SP600125 increased basal Ao gene expression in NRVM (10.52 ± 1.98 fold, P < 0.001) and NRFB (13.32 ± 2.07 fold, P < 0.001). Adenovirus-mediated expression of wild-type JNK1 significantly inhibited, whereas expression of dominant-negative JNK1 and JNK2 increased basal and stretch-mediated (24 h) Ao gene expression, showing both JNK1 and JNK2 to be negative regulators of Ao gene expression in NRVM and NRFB. Blockade of p38α/β by SB202190 or p38α by SB203580 significantly inhibited stretch-induced (24 h) Ao gene expression, whereas expression of wild-type p38α increased stretch-induced Ao gene expression in both NRVM (8.41 ± 1.50 fold, P < 0.001) and NRFB (3.39 ± 0.74 fold, P < 0.001). Conversely, expression of dominant-negative p38α significantly inhibited stretch response. Moreover, expression of constitutively active MKK6b (E) significantly stimulated Ao gene expression in the absence of stretch, indicating that p38 activation alone is sufficient to induce Ao gene expression. Taken together p38α was demonstrated to be a positive regulator, whereas JNK1/2 was found to be a negative regulator of Ao gene expression. Prolonged stretch diminished JNK1/2 activation, which was accompanied by a reciprocal increase in p38 activation and Ao gene expression. This suggests that a balance in JNK1/2 and p38α activation determines the level of Ao gene expression in myocardial cells.     

血管紧张素原基因多态性与血管性认知障碍关系的研究

目的 探讨血管紧张素原(AGT)基因G-6A和M235T多态性与血管性认知障碍(VCI)的关系.方法 采用随机对照研究,聚合酶链反应(PCR)方法检测VCI组(67例)、正常对照组(71例)AGT基因G-6A和M235T多态性.结果 VCI组AGT基因M235TT等位基因频率0.73,TT基因型频率0.52,与对照组(0.68,0.45)比较差异无统计学意义(P0.05),TT基因型对VCI的比数比为0.544(95%CI为0.208～1.424,P0.05).VCI组AGT基因G-6 A等位基因频率0.69,AA基因型频率0.48,与对照组(0.63,0.39)比较差异无统计学意义(P0.05),AA基因型对VCI的比数比为0.602(95%CI为0.252～1.738.P0.05).结论 脑梗死伴血管性认知障碍患者与AGT基因G-6A和M235T多态性无关,AGT基因这两个位点多态性未参与发病.     

门静脉高压性血管病变中血管紧张素原与核因子-kappa B的相关性研究及意义

目的:探讨肝硬化门静脉高压症(portal hypertension,PHT)时局部血管紧张素原mRNA表达与核因子-kappa B(nuclear factor-kappa B,NF-κB)的活化及相关性在门静脉高压性血管病变中的意义。方法:采用化学发光凝胶电泳迁移率(chemiluminescent electrophoretic mobility shift assay)方法检测局部NF-κB的活性;以逆转录-聚合酶链反应方法检测肝硬化PHT病人脾脏动、静脉组织和正常血管局部血管紧张素原mRNA的表达情况。结果:对照组内脾脏动、静脉组织局部血管紧张素原mRNA分别为0.23±0.12、0.18±0.10,显著低于肝硬化PHT组脾动、静脉组织局部血管紧张素原mRNA的表达[0.48±0.21、0.43±0.16,P<0.05];对照组脾动、静脉局部NF-κB未检测到明显的活性,于肝硬化PHT组检测到具显著活性NF-κB的表达(P<0.05);肝硬化PHT组脾脏动、静脉血管紧张素原mRNA表达与NF-κB的活性呈显著正相关(P<0.05)。结论:肝硬化PHT病人局部血管紧张素原mRNA表达增强、NF-κB的活化可能是肝硬化PHT时内脏血管病变形成和发展的原因之一。     

Renin substrate in human amniotic fluid

Purified human amniotic fluid renin substrate (RS) was compared to purified plasma RS. RS in plasma and amniotic fluid were similar in molecular weight, isoelectric point and immunological properties.

Immunoreactivity of radio-iodinated amniotic fluid RS was lower than that of plasma RS. Measured by direct radioimmunoassay, RS-levels were only 10–22% of those obtained with indirect assay in 22 amniotic fluid samples. This difference suggests that amniotic fluid RS is less immunoreactive than plasma RS, possibly due to biochemical alteration or complex formation. No such difference in immunoreactivity was noticed in RS of decidual and placental cytosolic fraction.     

Difference in expression of collagen type I and matrix metalloproteinase-1 in uterosacral ligaments of women with and without pelvic organ prolapse

Objectives

The objective of this study was to determine whether or not the angiotensin-converting enzyme insertion/deletion (ACE I/D), angiotensin II type 1 receptor (AT1R), and angiotensinogen (AGT) gene polymorphisms are associated with idiopathic recurrent spontaneous abortions (RSAs) in Korean women.

Study design

A total of 251 patients with unexplained consecutive pregnancy losses, and 126 healthy controls with at least one live birth and no history of pregnancy loss.

Result

The odds ratios (ORs) of the ACE ID (OR = 2.423; 95% confidence interval (CI) = 1.417–4.142; p = 0.001) and the ACE II (OR = 2.050; 95% CI = 1.143–3.675; p = 0.018) for the ACE DD genotype were significantly different between patients with idiopathic RSA and controls; however, there were no significant differences between patients and controls with respect to the AT1R 1166A>C and AGT M235 T polymorphisms. In a haplotype-based analysis of I-A (p = 0.010), D-A (p = 0.004), I-A-T (p = 0.033), D-A-T (p = 0.0005), and D-C-T (p = 0.013) polymorphism pairs with synergistic effects derived by the MDR method in patients and in controls showed significant results.

Conclusion

This study suggests that ACE, AT1R and AGT polymorphisms and haplotypes are a genetic determinant for the risk of idiopathic RSA in Korean women.     

妊高征与血管紧张素原基因M235T分子变异的关系

目的 :探讨中国成都地区人群中血管紧张素原 (AGT)基因 M2 35 T分子变异与妊娠高血压综合征 (PIH)的关系。方法 :采用聚合酶链反应及限制性片段长度多态性分析 ,对 6 0例 PIH患者和 6 0例正常孕妇进行 AGT基因 M2 35 T基因型及 T2 35等位基因检测。结果 :1在该研究的群体中未发现 AGT基因 2 35 TT型。 2 PIH患者 AGT基因 T2 35等位基因频率 (0 .4 6 )与对照组 (0 .4 3)相比无统计学差异 (P>0 .5 )。结论 :1AGT基因 M2 35 T分子变异与所研究人群 PIH的发生无关。 2 AGT基因 M2 35 T基因型和等位基因频率在不同人种和不同群体间是有差异的     

血管紧张素原基因M235T分子变异与心肌梗塞的关系

目的为探讨血管紧张素原（ＡＧＴ）基因Ｍ２３５Ｔ分子变异与心肌梗塞（ＭＩ）的关系。方法采用聚合酶链反应、限制性片段长度多态性分析，对５７例ＭＩ患者和７６例无冠心病证据的对照组进行ＡＧＴ基因Ｍ２３５Ｔ等位基因检测。结果ＭＩ患者ＡＧＴ基因２３５ＴＴ型（０．７０）和Ｔ２３５等位基因（０．８２）的频率显著高于对照组（分别为０．４２和０．６３，Ｐ＝０．０１３和Ｐ＜０．０２５）。经校正冠心病的主要危险因素后，ＡＧＴ基因２３５ＴＴ型仍可显著增加心肌梗塞发生的危险性（比数比３．６５，Ｐ＝０．０１６）。结论ＡＧＴ基因２３５ＴＴ型可能是中国人群ＭＩ发病的重要危险因素之一。     

Relationship between AGT rs2493132 polymorphism and the risk of coronary artery disease in patients with NAFLD in the Chinese Han population

ObjectiveTo investigate the relationship between angiotensin (AGT) rs2493132 gene polymorphism and the risk of developing non-alcoholic fatty liver disease (NAFLD) and coronary artery disease (CAD) in the Chinese Han population.MethodsPolymerase chain reaction was performed to determine AGT genotypes. Anthropometric and clinical data were investigated and statistically analyzed in the clinical laboratory department of Qingdao Municipal Hospital.ResultsThe AGT rs2493132 CT + TT genotype was an important risk factor for CAD in patients with NAFLD and NAFLD + CAD in healthy controls. The AGT rs2493132 T allele increased the risk of NAFLD + CAD in healthy controls. The AGT rs2493132 CT + TT genotype and T allele also significantly increased the risk of CAD in patients with NAFLD after adjustments for age, sex, and body mass index. In addition, AGT rs2493132 T allele carriers showed higher total cholesterol (TC) and low-density lipoprotein (LDL) levels compared with non-carriers.ConclusionsThe AGT rs2493132 CT + TT genotype and T allele significantly increased the risk of developing CAD in patients with NAFLD in the Chinese Han population. The AGT rs2493132 T allele was associated with increased serum TC and LDL levels.     

Association between T174M polymorphism in the angiotensinogen gene and risk of coronary artery disease: a meta-analysis

Background Angiotensinogen (AGT) T174M gene polymorphism has been suggested to be linked to risk of coronary artery disease, however, results from studies of this association have been inconsistent. In this study, we assess the relationship between AGT T174M gene polymorphism and coronary artery disease. Methods We conducted a meta-analysis of 18 case-control studies with 8,147 coronary artery disease cases and 5,344 controls in Google scholar, PubMed, Cochrane Library and China National Knowledge Infrastructure (CNKI) databases to identify eligible studies published by July, 2012. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated from these studies. Results Overall, a significant association was found between angiotensinogen T174M polymorphism and coronary artery disease risk when all studies were pooled into the meta-analysis (TT vs. MM: OR = 0.53, 95% CI = 0.40–0.71; dominant model: OR = 1.16, 95% CI = 1.01–1.35; recessive model: OR = 0.54, 95% CI = 0.40–0.72). In a stratified analysis, the results indicate a significant associa?tion in Caucasians suffering from coronary stenosis (TT vs. MM: OR = 0.38, 95% CI = 0.23–0.63; recessive model: OR = 0.39, 95% CI = 0.23–0.64). No significant increased risk for coronary artery disease was found in Asians. Conclusions The meta-analysis indicate a significant associa?tion of T174M polymorphism with coronary stenosis risk in Caucasians.     

Angiotensinogen Gene M235T and T174M Polymorphisms and Susceptibility of Pre-Eclampsia: A Meta-Analysis

There are controversies in reports on the association of the angiotensinogen (AGT) gene polymorphisms with the risk of developing pre-eclampsia (PE). We performed a meta-analysis to examine the association between the AGT polymorphisms and PE risk: M235T (31 studies involving 2555 patients and 6114 controls) and T174M (six studies involving 681 patients and 2076 controls). For the M235T polymorphism, the TT genotype increased the PE risk as compared to the MM genotype (odds ratio 1.61, 95% confidence intervals 1.22-2.14, P= 0.001). When stratified by ethnicity, the TT genotype remained significantly associated with higher PE risk in Caucasians and Mongolians but not in Africans. Similar results were also obtained under all three genetic models of the M235T polymorphism. For the T174M polymorphism, no significant association was found in the comparisons (MT vs. TT and MM vs. TT) and under any genetic models. The analysis excluding the highly significant Hardy-Weinberg equilibrium-violating studies and sensitivity analysis further strengthened the validity of these associations. No publication bias was observed in this study. This meta-analysis demonstrates that the AGT M235T polymorphism is significantly associated with PE whereas the T174M polymorphism is not.