MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation:implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus(T2DM)is a lifelong condition and a threat to human health.Thorough understanding of its pathogenesis is acutely needed in order to devise innovative,preventative,and potentially curative pharmacological interventions.MicroRNAs(miRNA),are small,non-coding,one-stranded RNA molecules,that can target and silence around 60%of all human genes through translational repression.MiR-155 is an ancient,evolutionarily well-conserved miRNA,with distinct expression profiles and multifunctionality,and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation,immunity,inflammation,viral infections,cancer,cardiovascular conditions,and particularly diabetes mellitus.MiR-155 Levels are progressively reduced in aging,obesity,sarcopenia,and T2DM.Thus,the loss of coordinated repression of multiple miR-155 targets acting as negative regulators,such as C/EBPβ,HDAC4,and SOCS1 impacts insulin signaling,deteriorating glucose homeostasis,and causing insulin resistance(IR).Moreover,deranged regulation of the renin angiotensin aldosterone system(RAAS)through loss of Angiotensin II Type 1 receptor downregulation,and negated repression of ETS-1,results in unopposed detrimental Angiotensin II effects,further promoting IR.Finally,loss of BACH1 and SOCS1 repression abolishes cytoprotective,anti-oxidant,anti-apoptotic,and anti-inflam matory cellular pathways,and promotesβ-cell loss.In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels,strategies to increase an ailing miR-155 production in T2DM,e.g.,the use of metformin,mineralocorticoid receptor blockers(spironolactone,eplerenone,finerenone),and verapamil,alone or in various combinations,represent current treatment options.In the future,direct tissue delivery of miRNA analogs is likely.

Effect of angiotensin Ⅱ type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

AIM： To investigate the effect of angiotensin II type 1 receptor blocker （ARB） and angiotensin converting enzyme inhibitor （ACEI） on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS： Forty Sprague-Dawley rats were divided into 4 groups： control, diabetes mellitus （DM）, candesartan- treated DM, and enalapril-treated DM （each group, n---10）. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/（kg · d）] and enalapril [ACEI, 10 mg/（kg · d）] were administered to rats orally for 4Wko Vascular endothelial growth factor （VEGF） and angiotensin II （Ang II） concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor （ATIR） levels were assessed at week 4 by Western blotting. RESULTS： Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control （P=0.04 and 0.005, respectively）. Vitreous ATIR increased significantly in DM compared to the other three groups （P〈0.007）. Candesartan-treated DM rats showed higher vitreal ATIR concentration than the enalapril-treated DM group and control （P〈0.001 and P=0.005, respectively）. No difference in vitreous Ang II and ATIR concentration was found between the enalapril- treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION： Increased Ang II and ATIR in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

Effect of nuclear factor-κB and angiotensin Ⅱ receptor type 1 on the pathogenesis of rat non-alcoholic fatty liver disease

AIM: To investigate the roles of nuclear factor(NF)-κB and angiotensin Ⅱ receptor type 1(AT1R) in the pathogenesis of non-alcoholic fatty liver disease(NAFLD).METHODS: Forty-two healthy adult male SpragueDawley rats were randomly divided into three groups:the control group(normal diet), the model group,and the intervention group(10 wk of a high-fat diet feeding, followed by an intraperitoneal injection of PDTC); 6 rats in each group were sacrificed at 6, 10,and 14 wk. After sacrifice, liver tissue was taken,paraffin sections of liver tissue specimens were prepared, hematoxylin and eosin(HE) staining was performed, and pathological changes in liver tissue(i.e., liver fibrosis) were observed by light microscopy.NF-κB expression in liver tissue was detected by immunohistochemistry, and the expression of AT1 R in the liver tissue was detected by reverse transcriptionpolymerase chain reaction(RT-PCR). The data are expressed as mean ± SD. A two-sample t test was used to compare the control group and the model group at different time points, paired t tests were used to compare the differences between the intervention group and the model group, and analysis of variance was used to compare the model group with the control group. Homogeneity of variance was analyzed with single factor analysis of variance. H variance analysis was used to compare the variance. P < 0.05 wasconsidered statistically significant.RESULTS: The NAFLD model was successful after 6wk and 10 wk. Liver fibrosis was found in four rats in the model group, but in only one rat in the intervention group at 14 wk. Liver steatosis, inflammation, and fibrosis were gradually increased throughout the model. In the intervention group, the body mass,rat liver index, serum lipid, and transaminase levels were not increased compared to the model group.In the model group, the degree of liver steatosis was increased at 6, 10, and 14 wk, and was significantly higher than in the control group(P < 0.01). In the model group, different degrees of liver cell necrosis were visible and small leaves, punctated inflammation,focal necrosis, and obvious ballooning degeneration were observed. Partial necrosis and confluent necrosis were observed. In the model group, liver inflammatory activity scores at 6, 10, and 14 wk were higher than in the control group(P < 0.01). Active inflammation in liver tissue in the intervention group was lower than in the model group(P < 0.05). HE staining showed liver fibrosis only at 14 wk in 4/6 rats in the model group and in 1/6 rats in the intervention group. NF-κB positive cells were stained yellow or ensemble yellow,and NF-κB was localized in the cytoplasm and/or nucleus. The model group showed NF-κB activation at6, 10, and 14 wk in liver cells; at the same time points,there were statistically significant differences in the control group(P < 0.01). Over time, NF-κB expression increased; this was statistically lower(P < 0.05) at14 weeks in the intervention group compared to the model group, but significantly increased(P < 0.05)compared with the control group; RT-PCR showed that AT1 R mRNA expression increased gradually in the model group; at 14 wk, the expression was significantly different compared with expression at 10 weeks as well as at 6 weeks(P < 0.05). In the model group, AT1 R mRNA expression was significantly higher than at the same time point in the control group(P <0.01).CONCLUSION: With increasing severity of NAFLD,NF-κB activity is enhanced, and the inhibition of NF-κB activity may reduce AT1 R mRNA expression in NAFLD.

Multiple templates-based homology modeling and docking analysis of angiotensin Ⅱ type 1 receptor

Using the latest reported homologous Chemokine receptors (PDB ID:3ODU,3OE0 and 3OE6) as templates,twenty models of angiotensin II (Ang II) type 1 (AT1) receptor (known as p30556) were generated by multiple templates homology modeling.According to the results of the initial validation of these twenty models,the model 0020 was finally chosen as the best one for further studies.Then,a 2 ns molecular dynamic (MD) simulation for model 0020 was conducted in normal saline (0.9%,w/V) under periodical boundary conditions,which was followed by docking studies of model 0020 with several existing AT1 receptor blockers (ARBs).The docking results reveal that model 0020 possesses good affinities with these docked ARBs which are in accordance with both the IC50 inhibitor values and their curative effects.The results also show more potent interactions between the model 0020 and its ARBs than those of ever reported results,such as hydrogen bonds,hydrophobic interactions,and especially cation-π interactions and π-π interactions which have never been reported before.This may reveal that the structure of the model 0020 is quite close to its real crystal structure and the model 0020 may have the potential to be used for structure based drug design.

Angiotensin receptor blocker drugs and inhibition of adrenal beta-arrestin-1-dependent aldosterone production: Implications for heart failure therapy

Aldosterone mediates many of the physiological and pathophysiological/cardio-toxic effects of angiotensin II(Ang II). Its synthesis and secretion from the zona glomerulosa cells of the adrenal cortex, elevated in chronic heart failure(HF), is induced by Ang II type 1 receptors(AT1Rs). The AT1R is a G protein-coupled receptor, mainly coupling to Gq/11 proteins. However, it can also signal through β-arrestin-1(βarr1) or-2(βarr2), both of which mediate G protein-independent signaling. Over the past decade, a second, Gq/11 proteinindependent but βarr1-dependent signaling pathway emanating from the adrenocortical AT1R and leading to aldosterone production has become appreciated. Thus, it became apparent that AT1R antagonists that block both pathways equally well are warranted for fully effective aldosterone suppression in HF. This spurred the comparison of all of the currently marketed angiotensin receptor blockers(ARBs, AT1R antagonists or sartans) at blocking activation of the two signaling modes(G protein-, and βarr1-dependent) at the Ang IIactivated AT1R and hence, at suppression of aldosterone in vitro and in vivo. Although all agents are very potent inhibitors of G protein activation at the AT1R, candesartan and valsartan were uncovered to be the most potent ARBs at blocking βarr activation by Ang II and at suppressing aldosterone in vitro and in vivo in post-myocardial infarction HF animals. In contrast, irbesartan and losartan are virtually G protein-"biased" blockers at the human AT1R, with very low efficacy for βarr inhibition and aldosterone suppression. Therefore, candesartan and valsartan(and other, structurally similar compounds) may be the most preferred ARB agents for HF pharmacotherapy, as well as for treatment of other conditions characterized by elevated aldosterone.

The role of angiotensinⅡtype 1 receptor pathway in cerebral ischemia-reperfusion injury:Implications for the neuroprotective effectof ARBs

Cerebral ischemia-reperfusion(I/R)injury is a crucial factor that impacts the prognosis of recanalization therapy for acute ischemic stroke(AIS).It has been found that the brain renin-angiotensin system,especially the angiotensinⅡtype 1 receptor(AT1R)pathway,plays a significant role in cerebral I/R injury.This pathway is involved in processes such as oxidative stress,neuroinflammation,apoptosis,and it affects cerebrovascular autoregulation and the maintenance of blood-brain barrier.AT1R blocker(ARB),widely used as an antihypertensive agent,has demonstrated stroke prevention capabilities in numerous prospective studies,independent of its antihypertensive characteristics.Studies focusing on neurological diseases like Alzheimer's disease,Parkinson's disease,and cognitive impairment have confirmed that ARBs exhibit neuroprotective effects and aid in improving neurological functions.Preclinical studies have shown that ARBs can reduce infarct volume and brain edema,inhibit multiple signaling pathways associated with I/R injury,restore energy levels in damaged brain regions,and rescue the penumbra by promoting neovascularization in cerebral I/R models.These findings suggest that ARBs have potential to become a novel category of neuroprotecting agents for clinical treatment of Als.Therefore,this review primarily provides a theoretical foundation and practical evidence for the future clinical utilization of ARBs as neuroprotective agents following reperfusion therapy for Als.It outlines the role of cerebral I/R injury through the AT1R pathway and highlights the research progressmadeonARBs in I/Rmodels.

Effects of AT1 receptor antagonist,Iosartan,on rat hepatic fibrosis induced by CCl_4

AIM To investigate effect of losartan,an AT1receptor antagonist,on hepatic fibrosis induced byCCl;and to determine whether or not AT1receptors are expressed on hepatic stellate cells,METHODS AND RESULTS Fifty male Sprague-Dawley rats,weighing（180±20）g,wererandomized into five groups（control group,modelgroup,and three losartan treated groups）,inwhich all rats were given the subcutaneousinjection of 40% CCl4（every 3 days for 6 weeks）except for rats of control group.Rats of losartan-treated groups were treated with losartan（20 mg/kg,10 mg/kg,5 mg/kg,daily gavage）,After 6weeks liver tissue and serum samples of all ratswere examined.Serum hyaluronic acid（HA）,procollagen typeⅢ（PCⅢ）were detected byradioimmunoassays,van Giesion collagen stainingwas used to evaluate the extracellular matrix of ratswith liver fibrosis.The expression of AT1receptors,transforming growth factor-beta（TGF-β）,and alpha-smooth muscle actin（a-SMA）inliver tissue were determined byimmunohistochemical techniques.Compared withmodel group,serum ALT and AST of losartan-treated groups were significantly reduced（t=4.20,P【0.01 and t=4.57,P【0.01）.Serum HAand PCⅢalso had significant differences（t=3.53,P【0.01 and t=2.20,P【0.05）.Thedegree of fibrosis was improved by losartan and correlated with the expressions of AT1 receptors,TGF-β,and α-SMA in liver tissue.CONCLUSION AT1 receptor antagonist,losartan,could limit the progression of the hepatic fibrosisinduced by CCl4.The mechanism may be related tothe decrease in the expression of AT1 receptorsand TGF-β,ameliorating the injury of hepatocytes;activation of local renin-angiotensin system mightrelate to hepatic fibrosis;and during progressionof fibrosis,activated hepatic stellate cells mightexpress AT1 receptors.

Effects on Cell Viability and on Apoptosis in Tumoral(MCF-7)and in Normal(MCF10A)Epithelial Breast Cells after Human Chorionic Gonadotropin and Derivated-Angiotensin Peptides Treatments

Angiotensin-(1 - 7) [Ang-(1 - 7)] is an endogenous heptapeptide hormone of the renin-angiotensin system that has antiproliferative properties. The aim of this work was to evaluate the anti-proliferative and pro-apoptotic properties of Ang-(1 - 7) and of Ang-(1 - 7)-substituents 9-fluorenylmethyloxycarbonyl (Fmoc) e Ang II-derivatives containing the TOAC (2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid) in normal (MCF10A) and in tumoral (MCF7) epithelial mammary cell lines. Both cell lines received an hCG and angiotensin peptides 24-hour treatment, in combination or alone followed by cell viability, apoptosis and cell cycle assays performed by flow cytometer (GUAVA). After hCG, Ang-(1 - 7), hCG + Ang-(1 - 7) and hCG + Ang-(1 - 7)-Fmoc treatments, MCF7 displayed cell viability decrease and mid-apoptosis increase. We also observed cell viability decrease in MCF10A after Ang-(1 - 7), Ang-(1 - 7) Fmoc and hCG + AngII Toac treatments. These cells had an increase in late apoptosis and necrosis after AngII Toac, hCG + Ang-(1 - 7) and hCG + Ang-(1 - 7)-Fmoc treatments. Regarding the cell cycle analysis, we did not observed any changes in cell cycle phases. In summary, cell viability was decreased and apoptosis (initial, mid and late) was increased after hCG and/or Ang-(1 - 7) peptides treatments. These results point out hCG and Ang-(1 - 7) as effective compounds to inhibit cell proliferation, since they decrease cell viability and increase apoptosis in both normal and in tumoral breast cells, being the effect more pronounced in the tumoral cell line. Our results support the idea of investigating more closely the putative use of these compounds as novel therapeutic agents for breast cancer.

AGTR1基因rs2638360位点多态性对中国人群缺血性脑卒中发生风险的影响

目的评估血管紧张素Ⅱ-1型受体(angiotensinⅡreceptoRtype 1,AGTR1)基因rs2638360位点单核苷酸多态性(single-nucleotide polymorphism,SNP)与缺血性脑卒中(ischemic stroke,IS)发生风险的前瞻性关联。方法利用“135”前瞻性队列研究(2013至2019)的数据,对1569名无血缘关系的中国成年人进行rs2638360位点的分型。使用R语言3.6.2的SNPassoc包评估rs2638360位点突变与IS发生风险的相关性,使用SAS 9.4利用Cox比例风险模型进行分层分析及叉生分析。结果6年的随访期间,68人(4.33%)发生IS。未发现AGTR1基因rs2638360位点单核苷酸多态性影响IS的发生风险,但在年龄≥51岁或低密度脂蛋白胆固醇(LDL-C)<2.58 mmol/L的研究对象中,与携带rs2638360位点TT基因型的个体比较,携带该位点TC/CC基因型的个体发生IS的风险增加(P<0.05),且rs2638360位点单核苷酸多态性与年龄或高密度脂蛋白胆固醇(HDL-C)可产生联合作用显著影响IS的发生风险(P<0.05)。结论携带rs2638360位点TC/CC基因型且年龄≥51岁或LDL-C水平较低的个体可能更容易发生IS,且rs2638360位点单核苷酸多态性与年龄或HDL-C可产生联合作用,显著影响中国人群发生IS的风险。

髓系细胞血管紧张素1型受体在盐敏感性高血压小鼠血管胰岛素抵抗和血管损伤中的作用

[目的]探究髓系细胞血管紧张素1型受体(Mye AT1R)在盐敏感性高血压小鼠血管胰岛素抵抗和血管损伤中的作用。[方法]采用左肾切除和去氧皮质酮乙酸酯(DOCA)缓释药片包埋术将C57BL/6J雄性小鼠(野生型,WT)和Mye AT1R敲除小鼠(Mye AT1R^(-/-))诱导为盐敏感性高血压小鼠模型,随机分为WT组、DOCA盐敏感性高血压组(简称DOCA组)、Mye AT1R^(-/-)组和Mye AT1R^(-/-)/DOCA组,每组8只。采用尾套袖法测量小鼠收缩压,HE染色观察主动脉壁厚度,免疫荧光检测主动脉F4/80(单核/巨噬细胞标志物),RT-PCR和Western blot检测AT1R、促炎细胞因子和胰岛素信号通路分子的mRNA和蛋白表达,离体血管灌流系统测定乙酰胆碱和胰岛素介导的内皮依赖性血管舒张功能。[结果]与WT组相比,DOCA组收缩压升高37%,主动脉壁厚度增加57%,乙酰胆碱和胰岛素介导的内皮依赖性血管舒张功能分别下降32%和36%(P<0.05),主动脉F4/80阳性细胞数量增多195%,单核细胞趋化蛋白1(MCP-1)、肿瘤坏死因子α(TNF-α)、磷酸化c-Jun氨基端激酶(p-JNK)蛋白表达升高42%、45%、32%,胰岛素蛋白激酶B(Akt)/内皮型一氧化氮合酶(eNOS)信号通路受损,p-Akt和p-eNOS的蛋白表达水平下降均为36%(P<0.05)。敲除Mye AT1R,主动脉壁厚度降低14%,F4/80阳性细胞数减少44%,乙酰胆碱和胰岛素介导的内皮依赖性血管舒张功能增加21%和17%,MCP-1、TNF-α和p-JNK蛋白表达水平降低52%、41%和17%,可修复受损的胰岛素PI3K/Akt/eNOS信号通路,p-Akt和p-eNOS的蛋白表达水平升高48%和42%(P<0.05),但收缩压没有明显降低。[结论]敲除Mye AT1R可减轻盐敏感性高血压引起的血管胰岛素抵抗和血管损伤,其机制可能与抑制巨噬细胞在血管壁浸润引起的血管炎症有关。

Plasma Levels of Angiotensin-Converting Enzymes 1 and 2 and <i>AGTR</i>2 (T1247G and A5235G) Gene Polymorphisms Are Associated to Breast Cancer Progression

Background: Breast cancer is the most common type of cancer among women. Diagnosed and treated timely, patients may have good prognostics. In Brazil, in 2012, the estimate of new cases was 52,680 and the number of registered deaths in 2012 was 12,852. The Renin-Angiotensin System (RAS) is known for its role in arterial hypertension and in other cardiovascular diseases. Angiotensin-Converting Enzyme 2 (ACE2) is the key to Ang-(1-7) formation, and counterbalances the ACE1/AngII/AGTR1 axis actions. RAS components have complex interactions with different tissues and their actions are not restricted to the cardiovascular system. Recently, the RAS has been associated with different types of cancers and in particular with gynecological cancers. Objectives: Our aim is to investigate possible associations between allelic distribution of two genetic polymorphisms in the AGTR2 receptor with ACEs 1 and 2 plasma levels among women with breast cancer. Patients and Methods: Patients with breast cancer were genotyped for two polymorphisms of the AGTR2 (T1247G and A5235G). Genotyping assays (TaqMan) were performed with genomic DNA extracted from blood cells. ACEs plasma level measurements were conducted in women from the breast-cancer group (N = 53). ACEs were measured in the plasma of these patients using ELISA kits. Results: SNPs genotype distribution is correlated with ACEs plasma levels. ACEs plasma levels are also correlated with clinical variables and ACE2 high levels are associated with better prognostics. Conclusions: Changes in circulating levels of ECA1/AngII ECA2/ Ang-(1-7) determine the magnitude of the inflammatory response that an individual can trigger and the variation in ACE 1 and 2 plasma level measurements in the blood of breast cancer patients suggests an association with the process of mammary carcinogenesis. Thus, the RAS may be associated with the process of mammary carcinogenesis by both genotypic variations of RAS components and by circulating levels of ACEs.

血管紧张素Ⅱ受体-1基因多态性与脑血管病的关系

目的探讨血管紧张素Ⅱ受体-1(AT1R)基因多态性与脑血管病(CVD)的关系。方法采用聚合酶链式-限制性片段长度多态性方法,检测104例CVD患者(CVD组)及98名健康人(正常对照组)的AT1R基因多态性,并进行分析。结果在研究总对象中没有发现CC基因型。CVD组AA、AC基因型频率分别为40.4%、59.6%,A、C等位基因频率分别为70.1%、29.9%;正常对照组AA、AC基因型频率分别为91.8%、8.1%,A、C等位基因频率分别为95.9%、4.1%。AT1R各基因型和等位基因频率在CVD组和正常对照组分布差异有显著性(均P<0.05)。结论AT1R基因多态性可能与CVD发病有关。

糖尿病肾病患者血清抗AT1和α1受体抗体与肾小球滤过率的关系

目的探讨糖尿病肾病(diabetic nephropathy,DN)患者血清抗血管紧张素II 1型受体自身抗体(angio-tensinⅡtype 1receptor activating antibody,AT1-AA)和抗α1肾上腺素能受体(α1-R)自身抗体与肾小球滤过率(glo-merular filtration rate,GFR)降低的相关性。方法①以合成的AT1受体和α1受体多肽片段为抗原,应用酶联免疫吸附测定(enzyme-linked immunosorbent assay,ELISA)技术,检测371例DN患者(A组)、107例2型糖尿病(type 2diabe-tes mellitus,T2DM)患者(B组)、47例正常对照(C组)自身抗体。②肾动态显像,采用同位素99 Tcm标记法测定GFR。③ELISA技术测定尿白蛋白排泄率(urinary albumin excretion rate,UAER)。结果①A组AT1和α1受体抗体阳性率分别为51.5%和47.7%,明显高于B组(19.5%和15.9%)及C组(10.6%和8.5%),P<0.05。②A组中,GFR异常者AT1和α1受体抗体阳性率分别为59.5%和63.1%,明显高于GFR正常者的30.5%和35.1%(P<0.01)。③A组中,GFR异常组中AT1和α1受体抗体均阳性者130例,阳性率为59.9%,显著高于GFR正常组(17.5%,27/154,P<0.01)。结论 DN患者GFR降低,血清抗AT1和α1受体抗体阳性率明显升高,糖尿病肾功能不全与抗AT1和α1受体自身抗体有关。

血管紧张素Ⅱ及其1型受体在肿瘤血管生成中的作用研究进展

血管紧张素Ⅱ(AngⅡ)是肾素-血管紧张素系统中的主要的多功能活性肽,其基本功能是调节血压和水、盐代谢平衡。然而,近年来的研究发现,AngⅡ作为一种潜在的生长因子,通过作用于其1型受体(AT1R)在肿瘤生长及血管生成中发挥着非常重要的作用。该文就近年来AngⅡ-AT1R系统在肿瘤血管生成中的作用研究作一概述。

AT_1R-CaN信号通路在乳鼠肥大心室肌细胞Nav1.5蛋白表达调控中的作用

目的:探讨血管紧张素Ⅱ1型受体(AT_1R)调神经磷酸酶(CaN)信号通路在乳鼠肥大心室肌细胞Nav1.5 mRNA和蛋白表达调控中的作用。方法:分离1日龄SD乳大鼠心室获心室肌细胞,分为对照(control)组、苯肾上腺素(PE)组、氯沙坦(Los)+PE组和环孢素A(CsA)+PE组;重组腺病毒shRNA干扰载体介导CaN A亚基β亚型(CnAβ)基因沉默分为腺病毒空载体(Ad-Null)组、Ad-Null+PE组、重组腺病毒CnAβshRNA1(AdCnAβshRNA1)组和Ad-CnAβshRNA1+PE组。实时荧光定量逆转录PCR检测脑钠尿肽(BNP)、β-肌球蛋白重链(β-MHC)和Nav1.5的mRNA表达。Western blot法检测全细胞提取蛋白CnAβ和Nav1.5的表达。结果:PE干预24 h明显增加心室肌细胞蛋白/DNA比值、细胞BNP和β-MHC的mRNA表达以及细胞面积;上调CnAβ蛋白表达,下调Nav1.5蛋白表达。CsA和Los干预明显抑制PE干预的上述效应。PE下调Nav1.5的mRNA表达,但Los和CsA不能抑制此种效应。Ad-CnAβshRNA1沉默乳鼠心室肌细胞CnAβ基因抑制了PE对BNP mRNA的上调作用,抑制了PE对Nav1.5蛋白表达的下调作用。结论:AT_1R-CaN信号通路参与调控培养的乳鼠肥大心室肌细胞Nav1.5蛋白表达的调控。

血管紧张素(1-7)在高盐高脂饮食诱导的代谢综合征小鼠肾脏损伤中的作用

目的采用高盐高脂饮食喂养C57BL/6小鼠建立代谢综合征(MS)模型,探讨血管紧张素转换酶2(ACE 2)及血管紧张素(1-7)[Ang(1-7)]在MS导致的肾脏损伤中的作用。方法 56只SPF级C57BL/6小鼠随机分为7组(每组8只),分别给予正常饮食(ND),高盐(HSD)饮食,高脂(HFD)饮食,高盐高脂(HSFD)饮食,以及分别采用依那普利20mg/(kg·d)+高盐高脂饮食(HSFD-E),缬沙坦50mg/(kg·d)+高盐高脂饮食(HSFD-V),缬沙坦50mg/(kg·d)+Ang(1-7)Mas受体抑制剂A-779 150ng/(kg·d)+高盐高脂饮食(HSFD-VA)。16周后检测血压、体重、血糖及尿蛋白排泄率等基础代谢指标,然后颈动脉取血,ELISA法检测血清中AngⅡ及Ang(1-7)水平,Western blotting检测肾脏中ACE 2及Ⅲ型胶原的表达,HE及Masson染色观察肾脏病理学改变。结果高盐高脂饮食喂养16周后,C57BL/6小鼠血压、内脏脂肪重量与体重比、血脂、血糖以及尿蛋白排泄率等各项代谢指标均明显升高(P<0.05);肾脏出现明显纤维化改变;血清AngⅡ水平升高,Ang(1-7)水平降低(P<0.01);肾脏组织中ACE2表达降低(P<0.05)。给予缬沙坦干预可明显缓解高盐高脂引起的代谢异常,肾脏损伤程度减轻,肾脏和血清中ACE2及Ang(1-7)表达增加(P<0.05)。给予依那普利或缬沙坦+A-779干预后上述指标与未干预组比较均无明显变化。结论应用高盐高脂饮食喂养C57BL/6小鼠可成功建立MS模型。AngⅡ受体1阻滞剂缬沙坦能够缓解高盐高脂导致的代谢异常和肾脏损伤,其对肾脏的保护机制可能与Ang(1-7)表达增加有关。

自发性高血压大鼠大、中动脉壁AT1和AT2受体表达的增龄性变化

目的以自发性高血压大鼠(SHR)为研究对象,探讨动脉血管壁胶原成分、血管紧张素Ⅱ受体(ATR)AT1和AT2亚型蛋白表达的增龄性改变。方法幼年组(7周)、成年组(26周)、老年组(51周)雄性SHR各20只,正常饮食饲养1周后,测定鼠尾动脉收缩压;胸主动脉及肠系膜上动脉(SMA)取材后,石蜡切片,Mallory染色观察壁纤维化程度,免疫组化SABC法测定ATR蛋白表达。结果 3个年龄组SHR大鼠的血压随增龄呈现明显升高[(151±26)mmHg vs.(166±9.0)mmHg vs.(180±13)mmHg,P<0.05];胸主动脉和SMA壁Ⅰ型和Ⅲ型胶原纤维沉积亦随增龄增多(IA值:主动脉416±43 vs.483±74 vs.553±83,SMA 387±46 vs.425±67 vs.468±81,P均<0.05);胸主动脉和SMA壁AT1和AT2表达均随年龄增长呈增高趋势(灰度值:胸主动脉AT1 159±7.0 vs.150±8.7 vs.139±8.9,AT2 187±6.9 vs.181±9.5 vs.169±10;SMA AT1 163±11 vs.112±11 vs.128±18,AT2 188±11 vs.171±15 vs.171±13;P均<0.05),AT1/AT2比值仅在老龄组增高(幼龄及老龄组胸主动脉0.86±0.01 vs.0.78±0.08;SMA 0.85±0.07 vs.0.71±0.08,P均<0.05)。结论增龄可导致SHR成纤维细胞生长、胶原纤维沉积,血管壁局部AT1、AT2表达及二者比例改变,同时AT1由单纯的介导血管收缩作用转变为介导血管壁重塑,可能是SHR大鼠血压增龄性改变的机制之一。

动脉粥样硬化性脑梗塞患者ACE基因与AT1R基因多态性分析

目的探讨在动脉粥样硬化性脑梗塞（ＡＣＩ）发生中血管紧张素转换酶（ＡＣＥ）基因与血管紧张素Ⅱ受体１型（ＡＴ１Ｒ）基因多态性的关系。方法采用聚合酶链反应－限制性片段长度多态性技术分别检测８１例ＡＣＩ患者和１０２例健康对照的ＡＣＥ和ＡＴ１Ｒ基因型。结果ＡＣＥ基因ＤＤ型与ＡＣＩ的发生显著相关（Ｐ＜０．０５）。在携带有ＡＣＥ基因ＤＤ型的群体中，ＡＴ１Ｒ基因型ＡＡ的个体患ＡＣＩ的比数比为１．３９，ＡＴ１Ｒ基因型ＡＣ患ＡＣＩ的比数比为３．６６，ＡＴ１Ｒ基因型ＣＣ患ＡＣＩ的比数比为５．８４。结论在ＡＣＩ发生中ＡＣＥ基因和ＡＴ１Ｒ基因多态性具有协同作用。

抗血管紧张素ⅡAT1受体抗体对大鼠脾脏T淋巴细胞的促增殖作用

目的观察抗AT1受体（AT1R）抗体对培养的大鼠脾脏T淋巴细胞增殖活性的影响。方法以人工合成的AT1R细胞外第二环肽段（AT1R—ECⅡ）为抗原主动免疫Wistar大鼠，利用亲和层析法提纯免疫大鼠血清中含有抗AT1R抗体的IgGs；培养大鼠脾淋巴细胞，刀豆蛋白A（ConA）诱导其活化和增殖，分别给予不同浓度的提纯IgGs（0．01、0．1、1umol／L）和血管紧张素Ⅱ进行干预，通过CCK-8法测定脾淋巴细胞增殖情况，并确定抗AT，R抗体的作用位点。结果ConA刺激48h后，大鼠脾淋巴细胞CCK-8吸光度显著高于空白对照组（0．38±0．05比0．27±0．02，P〈0．05）；不同浓度的IgGs剂量依赖性促进脾脏T淋巴细胞增殖（A值分别为0．53±0．03、0．71±0．04和0．94±0．05），与血管紧张素Ⅱ的作用相类似（A值为0．73±0．14、1．52±0．17和2．14±0．12）；AT1R特异性阻断剂Losartan和AT，R—ECⅡ均可显著减弱含抗AT1R抗体IgGs的促增殖效应（A值由0．71±0．04分别降为0．54±0．02，P〈0．01；0．52±0．04，P〈0．01）。结论抗AT1R抗体具有受体激动剂样效应，通过特异结合AT1R—ECⅡ剂量依赖性增强离体脾T淋巴细胞增殖活性。

AT_1R基因及CYP基因多态性与妊娠期高血压疾病的相关性

目的探讨妊娠期高血压疾病的分子遗传学机制。方法采用聚合酶链反应—限制性内切酶片段长度多态性技术(PCR-RFLP)分别检测87例妊娠期高血压疾病患者(观察组)和175例正常人(对照组)血管紧张素Ⅱ-1型受体(AT1R)基因A1166-C和醛固酮合成酶(CYP11B2)基因-344 T/C突变位点基因型。基因型及等位基因患妊娠期高血压疾病的风险率以比数比(OR)与95%可信区间(95%CI)表示。结果观察组中AT1R基因的AC基因型频率为33.3%,C等位基因频率为17.2%,相对于AA基因型、A等位基因,OR值分别为1.803、1.711;CYP11B2基因的TC和CC基因型频率分别为40.2%和17.2%,C等位基因频率为37.4%,相对于TT基因型、T等位基因,OR值分别为1.577、6.081、2.114;AT1R和CYP11B2联合基因型分析显示,相对于AA-TT联合基因型,同时携带AC-TC、AA-CC、AC-CC联合基因型的OR值分别为2.407、6.296、7.870。结论AT1R基因1166C和CYP11B2基因-344C点突变的等位基因可能增加妊娠期高血压疾病的遗传易感性;二者可能共同参与妊娠期高血压疾病的发生。