The expression of angiotensin Ⅱ type 1 receptor (AT1R) and angiotensin Ⅱ type 2 receptor (AT2R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes ...The expression of angiotensin Ⅱ type 1 receptor (AT1R) and angiotensin Ⅱ type 2 receptor (AT2R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes of APA was analyzed. The mRNA expression of AT1R and AT2R in 50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of AT1R and AT2R proteins in paraffin-embedded slices of tissue was detected by immunohistochemistry. The expression of AT1R in adenoma, tissues adjacent to tumor, and normal tissues of the adrenal gland showed no significant differences. The expression of AT2R in APA tissue was lower than that in normal adrenal gland tissues (P<0.05). Correlation analysis of the mRNA expression level of AT2R and clinical data from patients demonstrated that AT2R expression was negatively related to plasma aldosterone concentration (PAC) (r=-0.467, P<0.05), but positively related with plasma renin activity (PRA) (r=0.604, P<0.05). It is concluded that down-regulation of the AT2R expression is possibly related with the tumorigenesis of APA.展开更多
Objective The main purpose of this study was to investigate whether the folliculo stellate cells (FSC) respond to angiotensin(Ang)Ⅱ by increasing intracellular free Ca 2+ concentration ([Ca 2+ ]i),and where the origi...Objective The main purpose of this study was to investigate whether the folliculo stellate cells (FSC) respond to angiotensin(Ang)Ⅱ by increasing intracellular free Ca 2+ concentration ([Ca 2+ ]i),and where the origin of Ca 2+ mobilization is if that has occurred.Methods Pituitary cells in primary culture were prepared from male Wister rats(250g) by a conventional method and cultured in MEM supplemented with 4% normal rat serum.After 2 days in culutre,cells were loaded with 1 μmol/L fura PE3/AM for 1 h and subjected to a Ca 2+ imaging experiment with Quanti Cell 700 system.Excitation wavelengths of 340 and 380 nm were selected by means of a computer controlled filterwheel.Results The [Ca 2+ ]i of FSC in the rat anterior pituitary was elevated by Ang Ⅱ.The elevation of [Ca 2+ ]i of FSC induced by 0.1,1.0,10 and 100 nmol/L Ang Ⅱ was (56.33±6.18)( ±s ),(117.07±36.07),(175.59±40.01) and (216.02±11.52) nmol/L,respectively.The increase of [Ca 2+ ]i of FSC induced by 100 nmol/L Ang Ⅱ was not influenced by the medium without Ca 2+ (0Ca),but significantly suppressed by thapsigargin(TG),an inhibitor of ATPase.The rate of responsive FSC to Ang Ⅱ (100 nmol/L) was 61.84% which was obviously higher than that of pituitary endocrine cells(43.49%).Conclusion The present experiment demonstrates that the FSC in the rat anterior pituitary responds to Ang Ⅱ by increasing [Ca 2+ ]i,which raises the possibility that Ang Ⅱ released from either lactotrophs or gonadotrophs affects FSC through paracrine mechanism.The elevation of [Ca 2+ ]i induced by Ang Ⅱ presents a dosage dependent relation, and is possibly because of the release of Ca 2+ from an intracellular Ca 2+ pool(s).Fashions of Ca 2+ release are relative to the concentration of Ang Ⅱ.The results indicate that Ang Ⅱ functions as a paracrine factor among pituitary cells including FSC.展开更多
The changes of proto-oncogene c-fos and c-jun mRNA expression in angiotensin Ⅱ (AngⅡ)-induced hypertrophy and effects of sodium tanshinone ⅡA sulfonate (STS) in the primary culture of neonatal rat cardiomyocytes we...The changes of proto-oncogene c-fos and c-jun mRNA expression in angiotensin Ⅱ (AngⅡ)-induced hypertrophy and effects of sodium tanshinone ⅡA sulfonate (STS) in the primary culture of neonatal rat cardiomyocytes were investigated. Twelve neonatal clean grade Wistar rats were selected. The cardiomyocytes were isolated, cultured and divided according to different treatments in the medium. The cardiomyocyte size was determined by phase contrast microscope, and the rate of protein synthesis was measured by [3H]-Leucine incorporation. The c-fos and c-jun mRNA expression in cardiomyocytes was detected by reverse transcription polymerase chain reaction (RT-PCR). It was found after cardiomyocytes were treated with AngⅡ for 30 min, the c-fos and c-jun mRNA expression in cardiomyocytes was increased significantly (P<0.01). After treatment with AngⅡ for 24 h, the rate of protein synthesis in AngⅡ group was significantly increased as compared with control group (P<0.01). After treatment with AngⅡ for 7 days, the size of cardiomyocytes in AngⅡ group was increased obviously as compared with control group (P<0.05). After pretreatment with STS or Valsartan before AngⅡ treatment, both of them could inhibit the above effects of AngⅡ (P<0.05 or P<0.01). It was suggested that STS could ameliorate AngⅡ-induced cardiomyocyte hy- pertrophy by inhibiting c-fos and c-jun mRNA expression and reducing protein synthesis rate of cardiomyocytes.展开更多
AIM:To measure circulating angiotensins at different stages ofhuman cirrhosis and to further evaluate a possible relationship between renin angiotensin system (RAS) components and hemodynamic changes.METHODS: Patients...AIM:To measure circulating angiotensins at different stages ofhuman cirrhosis and to further evaluate a possible relationship between renin angiotensin system (RAS) components and hemodynamic changes.METHODS: Patients were allocated into 4 groups: mild-to-moderate liver disease (MLD), advanced liver disease (ALD), patients undergoing liver transplantation, and healthy controls. Blood was collected to determine plasma renin activity (PRA), angiotensin (Ang) , Ang Ⅱ, and Ang-(1-7) levels using radioimmunoassays. During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components.RESULTS: PRA and angiotensins were elevated in ALD when compared to MLD and controls (P < 0.05). In contrast, Ang was signicantly reduced in MLD. Ang-(1-7)/Ang Ⅱ ratios were increased in MLD when compared to controls and ALD. During transplantation, Ang Ⅱ levels were lower and Ang-(1-7)/Ang Ⅱ ratios were higher in the splanchnic circulation than in the peripheral circulation (0.52 ± 0.08 vs 0.38 ± 0.04, P < 0.02), whereas the peripheral circulating Ang /Ang ratio was elevated in comparison to splanchnic lev-els (0.18 ± 0.02 vs 0.13 ± 0.02, P < 0.04). Ang-(1-7)/Ang Ⅱ ratios positively correlated with cardiac output (r= 0.66) and negatively correlated with systemic vascular resistance (r =-0.70).CONCLUSION: Our ndings suggest that the relation-ship between Ang-(1-7) and Ang Ⅱmay play a role in the hemodynamic changes ofhuman cirrhosis.展开更多
The expression vector of shRNA targeted to the rat angiotensin Ⅱ receptor gene was constructed and the efficacy of siRNAs to modulate the expression of target gene in the in vitro cultured mammalian cells was investi...The expression vector of shRNA targeted to the rat angiotensin Ⅱ receptor gene was constructed and the efficacy of siRNAs to modulate the expression of target gene in the in vitro cultured mammalian cells was investigated for antihypertensive therapy in spontaneous hypertensive rat (SHR) at post-transcriptional level. The sense and antisense RNA oligonucleotides strands targeting angiotensin Ⅱ receptor mRNA were synthesized individually according to the sequence of the rat angiotensin Ⅱ receptor. For preparation of duplexes, sense-and antisense-stranded oligonucleotides were mixed and annealed, and the annealed duplexes were cloned into the pGenesil-1 vector. The rat glioma cells were transfected with constructed pGenesil-1-shRNA plasmid and scrambled plasmid. The cultured cells were collected at different phases. RT-PCR and Western blot were performed. The AT1 mRNA and protein levels behaved ultimately same. Compared to control after 48 h, AT1 mRNA levels were decreased to 35.5 %±3.0 %, and the levels reached their lowest point after 72 h (20.7 %±4 % of control). At 24 and 48 h, AT1 protein was reduced to 46.9 %±4.2 % and 36.98 %±3.7 % respectively compared to control and a maximum reduction was observed after 72 h of incubation (28.1 %±4 % compared to controls). Plasmid-based shRNA expression systems targeted against the rat angiotensin Ⅱ receptor gene were generated successfully. The shRNAs with a 22-nt stem and a short loop were cleaved into small interfering dsRNA (siRNA) by the Dicer. The in vitro transcribed siRNA enables the effective silencing of gene expression to the target mRNA and leads to effective inhibition of translation of proteins and will be lay the foundation of application of gene silencing technology to hypertensive rats.展开更多
Angiotensin Ⅱ (ANGⅡ) plays an important role in the pathogenesis of atherosclerosis by inducing proliferation of vascular smooth muscle cells (VSMCs).In our study,we observed the effects of valsartan on proliferatio...Angiotensin Ⅱ (ANGⅡ) plays an important role in the pathogenesis of atherosclerosis by inducing proliferation of vascular smooth muscle cells (VSMCs).In our study,we observed the effects of valsartan on proliferation of cultured VSMCs treated with or without ANGⅡ by cell counting and methyl thiazolyl tetrazolium (MTT) assay,and detected the expression of mitofusin 2 (Mfn2),a newly discovered cell proliferation inhibitor and a related cell proliferation signaling pathway pro-tein by Western blotting.ANGⅡ at a concentration of 10-6 mol/L significantly stimulated VSMCs proliferation,down-regulated the expression of Mfn2 and upregulated the expression of Raf and ERK1/2.Valsartan inhibited such effects of ANGⅡ at concentrations of 10-5 and 10-6 mol/L,but not at 10-7 mol/L.Valsartan had no significant effect on the proliferation of untreated VSMCs.These results suggest that valsartan inhibits ANGⅡ-induced proliferation of VSMCs in vitro via Mfn2-Ras-Raf-ERK/MAPK signaling pathway.展开更多
AIM: To investigate the effects of AT1 (Type 1 angiotensin Ⅱ receptor) antagonist (Losartan) on the apoptosis,proliferation and migration of the human pancreaticstellate cells (hPSCs).METHODS: hPSCs were isolated fro...AIM: To investigate the effects of AT1 (Type 1 angiotensin Ⅱ receptor) antagonist (Losartan) on the apoptosis,proliferation and migration of the human pancreaticstellate cells (hPSCs).METHODS: hPSCs were isolated from pancreatic sample of patients with pancreatic carcinoma using radioimmunoassay (RIA) technique to detect the concentration of AngⅡ in culture media and cell homogenate. Immunocytochemistry (ICC) and in situ hybridization (ISH) methods were utilized to test AT1 expression in hPSCs. Effects of Losartan on hPSCs proliferation, apoptosis and migration were investigated using BrdU incorporation, TUNEL, flow cytometry (FCM),and phase-contrast microscope separately when cells treated with Losartan. Immunofluorescence and Western blot were applied to quantify the expression of type Ⅰ collagen in hPSCs.RESULTS: There exists AT1 expression in hPSCs, while no AngⅡ was detected in culture media and cell homogenate. Losartan induces cell apoptosis in a doseand time-dependent manner (apparently at 10-5 mol/L),no pro-proliferative effect was observed in the same condition.Corresponding dosage of Losartan can also alleviate the motion capability and type Ⅰ collagen content of hPSCs compared with AngⅡ treatment and non-treatment control groups.CONCLUSION: These findings suggest that paracrine not autocrine functions of AngⅡ may have effects on hPSCs,which was mediated by AT1 expressed on cells, while Losartan may exert anti-fibrotic effects by inhibiting hPSCs motion and partly by inducing apoptosis.展开更多
Angiotensin Ⅱ(Ang Ⅱ), an endogenous peptide hormone, plays critical roles in the pathophysiological modulation of cardiovascular functions. Ang Ⅱ is the principle effector of the renin-angiotensin system for mainta...Angiotensin Ⅱ(Ang Ⅱ), an endogenous peptide hormone, plays critical roles in the pathophysiological modulation of cardiovascular functions. Ang Ⅱ is the principle effector of the renin-angiotensin system for maintaining homeostasis in the cardiovascular system, as well as a potent stimulator of NAD(P)H oxidase, which is the major source and primary trigger for reactive oxygen species(ROS) generation in various tissues. Recent accumulating evidence has demonstrated the importance of oxidative stress in Ang Ⅱ-induced heart diseases. Here, we review the recent progress in the study on oxidative stress-mediated effects of Ang Ⅱ in the cardiovascular system. In particular, the involvement of Ang Ⅱ-induced ROS generation in arrhythmias, cell death/heart failure, ischemia/reperfusion injury, cardiac hypertrophy and hypertension are discussed. Ca2+/calmodulin-dependent protein kinase Ⅱ is an important molecule linking Ang Ⅱ, ROS and cardiovascular pathological conditions.展开更多
To explore the relation of angiotensin-converting enzyme (ACE) and angiotensin Ⅱ type 1 receptor (AT1R) gene polymorphism with coronary heart disease (CHD) and the severity of coronary artery stenosis, 130 CHD patien...To explore the relation of angiotensin-converting enzyme (ACE) and angiotensin Ⅱ type 1 receptor (AT1R) gene polymorphism with coronary heart disease (CHD) and the severity of coronary artery stenosis, 130 CHD patients who underwent coronary angiography were examined for the number of affected coronary vessels (≥75% stenosis) and coronary Jeopardy score. The inser- tion/deletion of ACE gene polymorphism and AT1R gene polymorphism (an A→C transversion at nucleotide position 1166) were detected by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in CHD patients and 90 healthy serving as controls. The re- sults showed that DD genotype and of ACE were more frequent in CHD patients than that in control group (38.5% vs 14.4%, P<0.001). The frequency of the AT1R A/C genotypes did not differ between the patients and the controls (10% vs 13.1%, P>0.05). The relative risk associated with the ACE-DD was increased by AT1R-AC genotype. Neither the number of affected coronary vessels nor the coro- nary score differed among the ACE I/D genotypes (P>0.05). But the number of affected coronary vessels and the coronary score were significantly greater in the patients with the AT1R-AC genotype than in those with the AA genotype (P<0.05). In conclusion, DD genotype may be risk factor for CHD and MI in Chinese people, and is not responsible for the development of the coronary artery stenosis. The AT1R-C allele may increase the relative risk associated with the ACE-DD genotype, and may be involved in the development of the stenosis of coronary artery.展开更多
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...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.展开更多
The present study was designed to investigate the effect of microinfusion anglotensin Ⅱ (Ang Ⅱ ),Ang Ⅱ type l(AT1)receptor antagonist lesartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex ...The present study was designed to investigate the effect of microinfusion anglotensin Ⅱ (Ang Ⅱ ),Ang Ⅱ type l(AT1)receptor antagonist lesartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex sensitivity(BRS)in urethane-anesthetized rats. Methods: Reflex changes in heart rate(HR)were elicited by bolus intravenous injection of phenylephrine before and during RVLM microinfusion of saline(0.5μl/h), Ang Ⅱ(1.Snmol/h), losartan (250 nmol/h), and Ang Ⅱ (1.5 nmol/h) pretreated with microinjection of losartan (50 nmol/0.51 μl)into the RVLM. The average ratio between changes in HR in beats per minute(beats, min^-1 )and changes in mean arteriaI pressutre [ MAP,mmHg(1 mmHg = 0.133 kPa) ] was used as an index of BRS. Results : Ang Ⅱ resulted in a significant decrease in the BRS for reflex bradycardia compared with control( - 2.1 ~ 0.1 vs - 3.9 + 0.4 beats.min^-1·mmHg^-1 ).Microinfusion of losartan had no significant effect on BRS for reflex bradycardia.The effect of Ang ][ was almost completely abolished by pretreatment with microinjection of losartan. Conc/us/on: These results showed that the exogenous Ang II in the RVLM produces inhibitory modulation of BRS, which is mediated by AT2 receptor.However,AT1 receptor in the RVLM is not involved in the tonic control of BRS.展开更多
The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm(AAA) and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient(ApoE-/-) mic...The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm(AAA) and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient(ApoE-/-) mice, in which miniosmotic pump was implanted subcutaneously to deliver angiotensin Ⅱ(Ang Ⅱ) for 14 days. Male ApoE-/-mice were randomly divided into 3 groups: saline infusion, Ang Ⅱ infusion, and Ang Ⅱ infusion plus intraperitoneal injection of rapamycin. The diameter of the supra-renal abdominal aorta was measured by ultrasonography at the end of the infusion. Then aortic tissue was excised and examined by Western blotting and histoimmunochemistry. Ang Ⅱ with or without rapamycin treatment was applied to the cultured vascular smooth muscle cells(VSMCs) in vitro. The results revealed that rapamycin treatment significantly attenuated the incidence of Ang Ⅱinduced-AAA in ApoE-/-mice. Histologic analysis showed that rapamycin treatment decreased disarray of elastin fibers and VSMCs hyperplasia in the medial layer. Immunochemistry staining and Western blotting documented the increased phospho-ERKl/2 and ERK1/2 expression in aortic walls in Ang Ⅱ induced-AAA,as well as in human lesions. Whereas in the rapamycintreated group, decreased phospho-ERK1/2 expression level was detected. Moreover, rapamycin reversed Ang Ⅱ-induced VSMCs phenotypic change both in vivo and in vitro. Based on those results, we confirmed that rapamycin therapy suppressed Ang Ⅱ-induced AAA formation in mice, partially via VSMCs phenotypic modulation and down-regulation of ERK1/2 activity.展开更多
This study examined the effect of astilbin on the proliferation of rat aortic smooth muscle cells (RASMCs) induced by angiotensin Ⅱ (AngⅡ) and explored the possible mechanisms. Cell proliferation model of RASMCs was...This study examined the effect of astilbin on the proliferation of rat aortic smooth muscle cells (RASMCs) induced by angiotensin Ⅱ (AngⅡ) and explored the possible mechanisms. Cell proliferation model of RASMCs was induced by treatmente with AngⅡ. Cells were randomly di-vided to 8 groups. Normally cultured VSMCs serves as blank control group; in AngⅡ model group, cells were treated with AngⅡ at 10-7 mol/L; in three astilbin groups, cells were treated with 10, 15, 30 mg/L of astilbin; in three AngⅡ+astilbin groups, cells were treated with AngⅡ (at 10-7 mol/L) and astilbin at 10, 15, 30 mg/L. Cell proliferation ability was detected by MTT method and the cell cycles and proliferation index were flow cytometrically determined. The expression of c-myc mRNA was assessed by using reverse transcription polymerase chain reaction (RT-PCR), and the expression of NF-κB in RASMCs was immunocytochemically observed. Our results showed that MTT metabo-lism in RASMCs in the basic and AngII stimulated situation was inhibited by astilbin, and the cells numbers of G0/G1 phase were increased and that of G2/S phase were decreased markedly. Not only highly expression of c-myc gene stimulated by AngⅡ could be inhibited by Astilbin significantly, but also the expression of NF-κB protein can be down regulated by Astilbin. We are led to conclude that astilbin astilbin can inhibit the AngⅡ-mediated proliferation of RASMCs by blocking the tran-sition of RASMCs from G0/G1 phase to S phase and by down-regulating the expression of NF-κB, c-myc gene.展开更多
AIM To clarify whether Agtr1 a methylation is involved in the development of nonalcoholic steatohepatitis(NASH)-related liver fibrosis in adult rats.METHODS A choline-deficient amino acid(CDAA) diet model was employed...AIM To clarify whether Agtr1 a methylation is involved in the development of nonalcoholic steatohepatitis(NASH)-related liver fibrosis in adult rats.METHODS A choline-deficient amino acid(CDAA) diet model was employed for methylation analysis of NASH-related liver fibrosis.Agtr1 a methylation levels were measured in the livers of CDAA- and control choline-sufficient amino acid(CSAA)-fed rats for 8 and 12 wk using quantitative methylation-specific PCR.Hepatic stellate cells(HSCs) were isolated by collagenase digestion of the liver,followed by centrifugation of the crude cell suspension through a density gradient.Agtr1 a methylation and its gene expression were also analyzed during the activation of HSCs.RESULTS The mean levels of Agtr1 a methylation in the livers of CDAA-fed rats(11.5% and 18.6% at 8 and 12 wk,respectively) tended to be higher(P = 0.06 and 0.09,respectively) than those in the livers of CSAA-fed rats(2.1% and 5.3% at 8 and 12 wk,respectively).Agtr1 a was not methylated at all in quiescent HSCs,but was clearly methylated in activated HSCs(13.8%,P < 0.01).Interestingly,although Agtr1 a was hypermethylated,the Agtr1 a m RNA level increased up to 2.2-fold(P < 0.05) in activated HSCs compared with that in quiescent HSCs,suggesting that Agtr1 a methylation did not silence its expression but instead had the potential to upregulate its expression.These findings indicate that Agtr1 a methylation and its upregulation of gene expression are associated with the development of NASH-related liver fibrosis.CONCLUSION This is the first study to show that DNA methylation is potential y involved in the regulation of a renin-angiotensin system-related gene expression during liver fibrosis.展开更多
Renal tubules regulate blood pressure and humoral homeostasis.Mediators that play a significant role in regulating the transport of solutes and water include angiotensin Ⅱ(AngⅡ) and nitric oxide(NO).AngⅡ can signif...Renal tubules regulate blood pressure and humoral homeostasis.Mediators that play a significant role in regulating the transport of solutes and water include angiotensin Ⅱ(AngⅡ) and nitric oxide(NO).AngⅡ can significantly raise blood pressure via effects on the heart,vasculature,and renal tubules.AngⅡ generally stimulates sodium reabsorption by triggering sodium and fluid retention in almost all segments of renal tubules.Stimulation of renal proximal tubule(PT) transport is thought to be essential for AngⅡ-mediated hypertension.However,AngⅡ has a biphasic effect on in vitro PT transport in mice,rats,and rabbits:stimulation at low concentrations and inhibition at high concentrations.On the other hand,NO is generally thought to inhibit renal tubular transport.In PTs,NO seems to be involved in the inhibitory effect of AngⅡ.A recent study reports a surprising finding:AngⅡ has a monophasic stimulatory effect on human PT transport.Detailed analysis of signalling mechanisms indicates that in contrast to other species,the human NO/guanosine3',5'-cyclic monophosphate/extracellular signal-regulated kinase pathway seems to mediate this effect of AngⅡ on PT transport.In this review we will discuss recent progress in understanding the effects of AngⅡ and NO on renal tubular transport.展开更多
Objective Vascular endothelial cells senescence is one of major risk factors for atherosclerotic diseases,which can be induced by endogenous peptides,such as angiotensin Ⅱ(Ang Ⅱ).However,the effect of chronic Ang Ⅱ...Objective Vascular endothelial cells senescence is one of major risk factors for atherosclerotic diseases,which can be induced by endogenous peptides,such as angiotensin Ⅱ(Ang Ⅱ).However,the effect of chronic Ang Ⅱ stimulation on endothelial senescence remains unknown.Therefore,this study aims to investigate the changes in morphology and function of human umbilical vein endothelial cells(HUVECs)in response to the chronic stimulation of Ang Ⅱ.展开更多
Objective To investigate the combined effects of hypertension and angiotensinⅡon the risk of coronary heart disease(CHD)on the basis of a 10-year prospective study in an Inner Mongolian population of China.Methods Ba...Objective To investigate the combined effects of hypertension and angiotensinⅡon the risk of coronary heart disease(CHD)on the basis of a 10-year prospective study in an Inner Mongolian population of China.Methods Based on a cross-sectional survey,a prospective cohort study was conducted from June 2003 to July 2012 among 2,530 Mongolian people.展开更多
Objective To explore the effect of atorvastatin on cardiac hypertrophy and to determine the potential mechanism involved. Methods An in vitro cardiomyocyte hypertrophy from neonatal rats was induced with angiotensinⅡ...Objective To explore the effect of atorvastatin on cardiac hypertrophy and to determine the potential mechanism involved. Methods An in vitro cardiomyocyte hypertrophy from neonatal rats was induced with angiotensinⅡ(Ang Ⅱ) stimulation. Before AngⅡ stimulation, the cultured rat cardiac myocytes were pretreated with atorvastatin at different concentrations(0.1, 1, and 10 μmol/L). The following parameters were evaluated: the myocyte surface area, 3H-leucine incorporation into myocytes, m RNA expressions of atrial natriuretic peptide, brain natriuretic peptide, matrix metalloproteinase 9, matrix metalloproteinase 2, and interleukin-1β, m RNA and protein expressions of the δ/β peroxisome proliferator-activated receptor(PPAR) subtypes. Results It was shown that atorvastatin could ameliorate Ang Ⅱ-induced neonatal cardiomyocyte hypertrophy in the area of cardiomyocytes, 3H-leucine incorporation, and the expression of atrial natriuretic peptide and brain natriuretic peptide markedly. Meanwhile, atorvastatin also inhibited the augmented m RNA level of several cytokines in hypertrophic myocytes. Furthermore, the down-regulated expression of PPAR-δ/β at both the m RNA and protein levels in hypertrophic myocytes could be significantly reversed by atorvastatin treatment. Conclusions Atorvastatin could improve AngⅡ-induced cardiac hypertrophy and inhibit the expression of cytokines. Such effect might be partly achieved through activation of the PPAR-δ/β pathway.展开更多
Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (E...Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (ECAR), which was measured by Cytosensor microphysiometry, was significantly reduced in the aortic VSMCs from the cirrhotic rats as compared to those from the control animals. The ability of AT-Ⅱ to promote formation of inositol phosphates, the second messenger produced by the activation of Gq-coupled receptors, was also considerably suppressed in the cirrhotic VSMCs. Furthermore, the maximal p42/44 MAPK phosphorylation stimulated by AT-Ⅱ was significantly reduced in the cirrhotic VSMCs in contrast to that in the normal VSMCs. Taken together, our data clearly demonstrated that the functional responses to AT-Ⅱ was severely suppressed in aortic VSMCs in cirrhosis, indicating the impairment of general Gq-coupled receptor signaling and subsequent biological function in the cirrhotic VSMCs.展开更多
基金supported by the National Natural Science Founds for Distinguished Young Scholar of China (No. 30725040)
文摘The expression of angiotensin Ⅱ type 1 receptor (AT1R) and angiotensin Ⅱ type 2 receptor (AT2R) in aldosterone-producing adenoma (APA) of the adrenal gland was detected, and their relationship with clinical indexes of APA was analyzed. The mRNA expression of AT1R and AT2R in 50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of AT1R and AT2R proteins in paraffin-embedded slices of tissue was detected by immunohistochemistry. The expression of AT1R in adenoma, tissues adjacent to tumor, and normal tissues of the adrenal gland showed no significant differences. The expression of AT2R in APA tissue was lower than that in normal adrenal gland tissues (P<0.05). Correlation analysis of the mRNA expression level of AT2R and clinical data from patients demonstrated that AT2R expression was negatively related to plasma aldosterone concentration (PAC) (r=-0.467, P<0.05), but positively related with plasma renin activity (PRA) (r=0.604, P<0.05). It is concluded that down-regulation of the AT2R expression is possibly related with the tumorigenesis of APA.
基金Present address:Departm ent of PhysiologyMedical College of Xi'an Jiaotong University+1 种基金Xi'an 710 0 6 1China
文摘Objective The main purpose of this study was to investigate whether the folliculo stellate cells (FSC) respond to angiotensin(Ang)Ⅱ by increasing intracellular free Ca 2+ concentration ([Ca 2+ ]i),and where the origin of Ca 2+ mobilization is if that has occurred.Methods Pituitary cells in primary culture were prepared from male Wister rats(250g) by a conventional method and cultured in MEM supplemented with 4% normal rat serum.After 2 days in culutre,cells were loaded with 1 μmol/L fura PE3/AM for 1 h and subjected to a Ca 2+ imaging experiment with Quanti Cell 700 system.Excitation wavelengths of 340 and 380 nm were selected by means of a computer controlled filterwheel.Results The [Ca 2+ ]i of FSC in the rat anterior pituitary was elevated by Ang Ⅱ.The elevation of [Ca 2+ ]i of FSC induced by 0.1,1.0,10 and 100 nmol/L Ang Ⅱ was (56.33±6.18)( ±s ),(117.07±36.07),(175.59±40.01) and (216.02±11.52) nmol/L,respectively.The increase of [Ca 2+ ]i of FSC induced by 100 nmol/L Ang Ⅱ was not influenced by the medium without Ca 2+ (0Ca),but significantly suppressed by thapsigargin(TG),an inhibitor of ATPase.The rate of responsive FSC to Ang Ⅱ (100 nmol/L) was 61.84% which was obviously higher than that of pituitary endocrine cells(43.49%).Conclusion The present experiment demonstrates that the FSC in the rat anterior pituitary responds to Ang Ⅱ by increasing [Ca 2+ ]i,which raises the possibility that Ang Ⅱ released from either lactotrophs or gonadotrophs affects FSC through paracrine mechanism.The elevation of [Ca 2+ ]i induced by Ang Ⅱ presents a dosage dependent relation, and is possibly because of the release of Ca 2+ from an intracellular Ca 2+ pool(s).Fashions of Ca 2+ release are relative to the concentration of Ang Ⅱ.The results indicate that Ang Ⅱ functions as a paracrine factor among pituitary cells including FSC.
基金a grant from National Natural Sciences Foundation of China (No. 30500657)
文摘The changes of proto-oncogene c-fos and c-jun mRNA expression in angiotensin Ⅱ (AngⅡ)-induced hypertrophy and effects of sodium tanshinone ⅡA sulfonate (STS) in the primary culture of neonatal rat cardiomyocytes were investigated. Twelve neonatal clean grade Wistar rats were selected. The cardiomyocytes were isolated, cultured and divided according to different treatments in the medium. The cardiomyocyte size was determined by phase contrast microscope, and the rate of protein synthesis was measured by [3H]-Leucine incorporation. The c-fos and c-jun mRNA expression in cardiomyocytes was detected by reverse transcription polymerase chain reaction (RT-PCR). It was found after cardiomyocytes were treated with AngⅡ for 30 min, the c-fos and c-jun mRNA expression in cardiomyocytes was increased significantly (P<0.01). After treatment with AngⅡ for 24 h, the rate of protein synthesis in AngⅡ group was significantly increased as compared with control group (P<0.01). After treatment with AngⅡ for 7 days, the size of cardiomyocytes in AngⅡ group was increased obviously as compared with control group (P<0.05). After pretreatment with STS or Valsartan before AngⅡ treatment, both of them could inhibit the above effects of AngⅡ (P<0.05 or P<0.01). It was suggested that STS could ameliorate AngⅡ-induced cardiomyocyte hy- pertrophy by inhibiting c-fos and c-jun mRNA expression and reducing protein synthesis rate of cardiomyocytes.
基金Supported by Fundacode Amparo à Pesquisa do Estado de Minas Gerais, Conselho Nacional de Desenvolvimento Científico e Tecnológico, FAPEMIG/CNPQ-PRONEX (Grupos de Excelência),Ministério de Ciência e Tecnologia/CNPq/ FAPEMIG-INCT-Nano-Biofar
文摘AIM:To measure circulating angiotensins at different stages ofhuman cirrhosis and to further evaluate a possible relationship between renin angiotensin system (RAS) components and hemodynamic changes.METHODS: Patients were allocated into 4 groups: mild-to-moderate liver disease (MLD), advanced liver disease (ALD), patients undergoing liver transplantation, and healthy controls. Blood was collected to determine plasma renin activity (PRA), angiotensin (Ang) , Ang Ⅱ, and Ang-(1-7) levels using radioimmunoassays. During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components.RESULTS: PRA and angiotensins were elevated in ALD when compared to MLD and controls (P < 0.05). In contrast, Ang was signicantly reduced in MLD. Ang-(1-7)/Ang Ⅱ ratios were increased in MLD when compared to controls and ALD. During transplantation, Ang Ⅱ levels were lower and Ang-(1-7)/Ang Ⅱ ratios were higher in the splanchnic circulation than in the peripheral circulation (0.52 ± 0.08 vs 0.38 ± 0.04, P < 0.02), whereas the peripheral circulating Ang /Ang ratio was elevated in comparison to splanchnic lev-els (0.18 ± 0.02 vs 0.13 ± 0.02, P < 0.04). Ang-(1-7)/Ang Ⅱ ratios positively correlated with cardiac output (r= 0.66) and negatively correlated with systemic vascular resistance (r =-0.70).CONCLUSION: Our ndings suggest that the relation-ship between Ang-(1-7) and Ang Ⅱmay play a role in the hemodynamic changes ofhuman cirrhosis.
文摘The expression vector of shRNA targeted to the rat angiotensin Ⅱ receptor gene was constructed and the efficacy of siRNAs to modulate the expression of target gene in the in vitro cultured mammalian cells was investigated for antihypertensive therapy in spontaneous hypertensive rat (SHR) at post-transcriptional level. The sense and antisense RNA oligonucleotides strands targeting angiotensin Ⅱ receptor mRNA were synthesized individually according to the sequence of the rat angiotensin Ⅱ receptor. For preparation of duplexes, sense-and antisense-stranded oligonucleotides were mixed and annealed, and the annealed duplexes were cloned into the pGenesil-1 vector. The rat glioma cells were transfected with constructed pGenesil-1-shRNA plasmid and scrambled plasmid. The cultured cells were collected at different phases. RT-PCR and Western blot were performed. The AT1 mRNA and protein levels behaved ultimately same. Compared to control after 48 h, AT1 mRNA levels were decreased to 35.5 %±3.0 %, and the levels reached their lowest point after 72 h (20.7 %±4 % of control). At 24 and 48 h, AT1 protein was reduced to 46.9 %±4.2 % and 36.98 %±3.7 % respectively compared to control and a maximum reduction was observed after 72 h of incubation (28.1 %±4 % compared to controls). Plasmid-based shRNA expression systems targeted against the rat angiotensin Ⅱ receptor gene were generated successfully. The shRNAs with a 22-nt stem and a short loop were cleaved into small interfering dsRNA (siRNA) by the Dicer. The in vitro transcribed siRNA enables the effective silencing of gene expression to the target mRNA and leads to effective inhibition of translation of proteins and will be lay the foundation of application of gene silencing technology to hypertensive rats.
基金supported by grants from the National Natural Science Foundation of China (No. 30872714 and No.30971244)
文摘Angiotensin Ⅱ (ANGⅡ) plays an important role in the pathogenesis of atherosclerosis by inducing proliferation of vascular smooth muscle cells (VSMCs).In our study,we observed the effects of valsartan on proliferation of cultured VSMCs treated with or without ANGⅡ by cell counting and methyl thiazolyl tetrazolium (MTT) assay,and detected the expression of mitofusin 2 (Mfn2),a newly discovered cell proliferation inhibitor and a related cell proliferation signaling pathway pro-tein by Western blotting.ANGⅡ at a concentration of 10-6 mol/L significantly stimulated VSMCs proliferation,down-regulated the expression of Mfn2 and upregulated the expression of Raf and ERK1/2.Valsartan inhibited such effects of ANGⅡ at concentrations of 10-5 and 10-6 mol/L,but not at 10-7 mol/L.Valsartan had no significant effect on the proliferation of untreated VSMCs.These results suggest that valsartan inhibits ANGⅡ-induced proliferation of VSMCs in vitro via Mfn2-Ras-Raf-ERK/MAPK signaling pathway.
基金Supported by Shanghai Sanitary Bureau Foundation, No. 40306
文摘AIM: To investigate the effects of AT1 (Type 1 angiotensin Ⅱ receptor) antagonist (Losartan) on the apoptosis,proliferation and migration of the human pancreaticstellate cells (hPSCs).METHODS: hPSCs were isolated from pancreatic sample of patients with pancreatic carcinoma using radioimmunoassay (RIA) technique to detect the concentration of AngⅡ in culture media and cell homogenate. Immunocytochemistry (ICC) and in situ hybridization (ISH) methods were utilized to test AT1 expression in hPSCs. Effects of Losartan on hPSCs proliferation, apoptosis and migration were investigated using BrdU incorporation, TUNEL, flow cytometry (FCM),and phase-contrast microscope separately when cells treated with Losartan. Immunofluorescence and Western blot were applied to quantify the expression of type Ⅰ collagen in hPSCs.RESULTS: There exists AT1 expression in hPSCs, while no AngⅡ was detected in culture media and cell homogenate. Losartan induces cell apoptosis in a doseand time-dependent manner (apparently at 10-5 mol/L),no pro-proliferative effect was observed in the same condition.Corresponding dosage of Losartan can also alleviate the motion capability and type Ⅰ collagen content of hPSCs compared with AngⅡ treatment and non-treatment control groups.CONCLUSION: These findings suggest that paracrine not autocrine functions of AngⅡ may have effects on hPSCs,which was mediated by AT1 expressed on cells, while Losartan may exert anti-fibrotic effects by inhibiting hPSCs motion and partly by inducing apoptosis.
基金Supported by A NIH R01 Grant,No.HL097979(to Xie LH)
文摘Angiotensin Ⅱ(Ang Ⅱ), an endogenous peptide hormone, plays critical roles in the pathophysiological modulation of cardiovascular functions. Ang Ⅱ is the principle effector of the renin-angiotensin system for maintaining homeostasis in the cardiovascular system, as well as a potent stimulator of NAD(P)H oxidase, which is the major source and primary trigger for reactive oxygen species(ROS) generation in various tissues. Recent accumulating evidence has demonstrated the importance of oxidative stress in Ang Ⅱ-induced heart diseases. Here, we review the recent progress in the study on oxidative stress-mediated effects of Ang Ⅱ in the cardiovascular system. In particular, the involvement of Ang Ⅱ-induced ROS generation in arrhythmias, cell death/heart failure, ischemia/reperfusion injury, cardiac hypertrophy and hypertension are discussed. Ca2+/calmodulin-dependent protein kinase Ⅱ is an important molecule linking Ang Ⅱ, ROS and cardiovascular pathological conditions.
文摘To explore the relation of angiotensin-converting enzyme (ACE) and angiotensin Ⅱ type 1 receptor (AT1R) gene polymorphism with coronary heart disease (CHD) and the severity of coronary artery stenosis, 130 CHD patients who underwent coronary angiography were examined for the number of affected coronary vessels (≥75% stenosis) and coronary Jeopardy score. The inser- tion/deletion of ACE gene polymorphism and AT1R gene polymorphism (an A→C transversion at nucleotide position 1166) were detected by using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) in CHD patients and 90 healthy serving as controls. The re- sults showed that DD genotype and of ACE were more frequent in CHD patients than that in control group (38.5% vs 14.4%, P<0.001). The frequency of the AT1R A/C genotypes did not differ between the patients and the controls (10% vs 13.1%, P>0.05). The relative risk associated with the ACE-DD was increased by AT1R-AC genotype. Neither the number of affected coronary vessels nor the coro- nary score differed among the ACE I/D genotypes (P>0.05). But the number of affected coronary vessels and the coronary score were significantly greater in the patients with the AT1R-AC genotype than in those with the AA genotype (P<0.05). In conclusion, DD genotype may be risk factor for CHD and MI in Chinese people, and is not responsible for the development of the coronary artery stenosis. The AT1R-C allele may increase the relative risk associated with the ACE-DD genotype, and may be involved in the development of the stenosis of coronary artery.
基金Supported by grants from the Science and Technology Department of Sichuan Province,No.2011SZ0094
文摘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.
文摘The present study was designed to investigate the effect of microinfusion anglotensin Ⅱ (Ang Ⅱ ),Ang Ⅱ type l(AT1)receptor antagonist lesartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex sensitivity(BRS)in urethane-anesthetized rats. Methods: Reflex changes in heart rate(HR)were elicited by bolus intravenous injection of phenylephrine before and during RVLM microinfusion of saline(0.5μl/h), Ang Ⅱ(1.Snmol/h), losartan (250 nmol/h), and Ang Ⅱ (1.5 nmol/h) pretreated with microinjection of losartan (50 nmol/0.51 μl)into the RVLM. The average ratio between changes in HR in beats per minute(beats, min^-1 )and changes in mean arteriaI pressutre [ MAP,mmHg(1 mmHg = 0.133 kPa) ] was used as an index of BRS. Results : Ang Ⅱ resulted in a significant decrease in the BRS for reflex bradycardia compared with control( - 2.1 ~ 0.1 vs - 3.9 + 0.4 beats.min^-1·mmHg^-1 ).Microinfusion of losartan had no significant effect on BRS for reflex bradycardia.The effect of Ang ][ was almost completely abolished by pretreatment with microinjection of losartan. Conc/us/on: These results showed that the exogenous Ang II in the RVLM produces inhibitory modulation of BRS, which is mediated by AT2 receptor.However,AT1 receptor in the RVLM is not involved in the tonic control of BRS.
基金supported by grants from the National Natural Science Foundation of China(No.81570325)the Fundamental Research Funds for the Central Universities
文摘The aim of the present study is to address the effect of rapamycin on abdominal aortic aneurysm(AAA) and the potential mechanisms. A clinically relevant AAA model was induced in apolipoprotein E-deficient(ApoE-/-) mice, in which miniosmotic pump was implanted subcutaneously to deliver angiotensin Ⅱ(Ang Ⅱ) for 14 days. Male ApoE-/-mice were randomly divided into 3 groups: saline infusion, Ang Ⅱ infusion, and Ang Ⅱ infusion plus intraperitoneal injection of rapamycin. The diameter of the supra-renal abdominal aorta was measured by ultrasonography at the end of the infusion. Then aortic tissue was excised and examined by Western blotting and histoimmunochemistry. Ang Ⅱ with or without rapamycin treatment was applied to the cultured vascular smooth muscle cells(VSMCs) in vitro. The results revealed that rapamycin treatment significantly attenuated the incidence of Ang Ⅱinduced-AAA in ApoE-/-mice. Histologic analysis showed that rapamycin treatment decreased disarray of elastin fibers and VSMCs hyperplasia in the medial layer. Immunochemistry staining and Western blotting documented the increased phospho-ERKl/2 and ERK1/2 expression in aortic walls in Ang Ⅱ induced-AAA,as well as in human lesions. Whereas in the rapamycintreated group, decreased phospho-ERK1/2 expression level was detected. Moreover, rapamycin reversed Ang Ⅱ-induced VSMCs phenotypic change both in vivo and in vitro. Based on those results, we confirmed that rapamycin therapy suppressed Ang Ⅱ-induced AAA formation in mice, partially via VSMCs phenotypic modulation and down-regulation of ERK1/2 activity.
基金supported by agrant from the National Natural Science Foundation of China(No.30500656)
文摘This study examined the effect of astilbin on the proliferation of rat aortic smooth muscle cells (RASMCs) induced by angiotensin Ⅱ (AngⅡ) and explored the possible mechanisms. Cell proliferation model of RASMCs was induced by treatmente with AngⅡ. Cells were randomly di-vided to 8 groups. Normally cultured VSMCs serves as blank control group; in AngⅡ model group, cells were treated with AngⅡ at 10-7 mol/L; in three astilbin groups, cells were treated with 10, 15, 30 mg/L of astilbin; in three AngⅡ+astilbin groups, cells were treated with AngⅡ (at 10-7 mol/L) and astilbin at 10, 15, 30 mg/L. Cell proliferation ability was detected by MTT method and the cell cycles and proliferation index were flow cytometrically determined. The expression of c-myc mRNA was assessed by using reverse transcription polymerase chain reaction (RT-PCR), and the expression of NF-κB in RASMCs was immunocytochemically observed. Our results showed that MTT metabo-lism in RASMCs in the basic and AngII stimulated situation was inhibited by astilbin, and the cells numbers of G0/G1 phase were increased and that of G2/S phase were decreased markedly. Not only highly expression of c-myc gene stimulated by AngⅡ could be inhibited by Astilbin significantly, but also the expression of NF-κB protein can be down regulated by Astilbin. We are led to conclude that astilbin astilbin can inhibit the AngⅡ-mediated proliferation of RASMCs by blocking the tran-sition of RASMCs from G0/G1 phase to S phase and by down-regulating the expression of NF-κB, c-myc gene.
文摘AIM To clarify whether Agtr1 a methylation is involved in the development of nonalcoholic steatohepatitis(NASH)-related liver fibrosis in adult rats.METHODS A choline-deficient amino acid(CDAA) diet model was employed for methylation analysis of NASH-related liver fibrosis.Agtr1 a methylation levels were measured in the livers of CDAA- and control choline-sufficient amino acid(CSAA)-fed rats for 8 and 12 wk using quantitative methylation-specific PCR.Hepatic stellate cells(HSCs) were isolated by collagenase digestion of the liver,followed by centrifugation of the crude cell suspension through a density gradient.Agtr1 a methylation and its gene expression were also analyzed during the activation of HSCs.RESULTS The mean levels of Agtr1 a methylation in the livers of CDAA-fed rats(11.5% and 18.6% at 8 and 12 wk,respectively) tended to be higher(P = 0.06 and 0.09,respectively) than those in the livers of CSAA-fed rats(2.1% and 5.3% at 8 and 12 wk,respectively).Agtr1 a was not methylated at all in quiescent HSCs,but was clearly methylated in activated HSCs(13.8%,P < 0.01).Interestingly,although Agtr1 a was hypermethylated,the Agtr1 a m RNA level increased up to 2.2-fold(P < 0.05) in activated HSCs compared with that in quiescent HSCs,suggesting that Agtr1 a methylation did not silence its expression but instead had the potential to upregulate its expression.These findings indicate that Agtr1 a methylation and its upregulation of gene expression are associated with the development of NASH-related liver fibrosis.CONCLUSION This is the first study to show that DNA methylation is potential y involved in the regulation of a renin-angiotensin system-related gene expression during liver fibrosis.
文摘Renal tubules regulate blood pressure and humoral homeostasis.Mediators that play a significant role in regulating the transport of solutes and water include angiotensin Ⅱ(AngⅡ) and nitric oxide(NO).AngⅡ can significantly raise blood pressure via effects on the heart,vasculature,and renal tubules.AngⅡ generally stimulates sodium reabsorption by triggering sodium and fluid retention in almost all segments of renal tubules.Stimulation of renal proximal tubule(PT) transport is thought to be essential for AngⅡ-mediated hypertension.However,AngⅡ has a biphasic effect on in vitro PT transport in mice,rats,and rabbits:stimulation at low concentrations and inhibition at high concentrations.On the other hand,NO is generally thought to inhibit renal tubular transport.In PTs,NO seems to be involved in the inhibitory effect of AngⅡ.A recent study reports a surprising finding:AngⅡ has a monophasic stimulatory effect on human PT transport.Detailed analysis of signalling mechanisms indicates that in contrast to other species,the human NO/guanosine3',5'-cyclic monophosphate/extracellular signal-regulated kinase pathway seems to mediate this effect of AngⅡ on PT transport.In this review we will discuss recent progress in understanding the effects of AngⅡ and NO on renal tubular transport.
文摘Objective Vascular endothelial cells senescence is one of major risk factors for atherosclerotic diseases,which can be induced by endogenous peptides,such as angiotensin Ⅱ(Ang Ⅱ).However,the effect of chronic Ang Ⅱ stimulation on endothelial senescence remains unknown.Therefore,this study aims to investigate the changes in morphology and function of human umbilical vein endothelial cells(HUVECs)in response to the chronic stimulation of Ang Ⅱ.
文摘Objective To investigate the combined effects of hypertension and angiotensinⅡon the risk of coronary heart disease(CHD)on the basis of a 10-year prospective study in an Inner Mongolian population of China.Methods Based on a cross-sectional survey,a prospective cohort study was conducted from June 2003 to July 2012 among 2,530 Mongolian people.
基金Supported by the National Basic Research Program(973 Program)(2013CB530804)
文摘Objective To explore the effect of atorvastatin on cardiac hypertrophy and to determine the potential mechanism involved. Methods An in vitro cardiomyocyte hypertrophy from neonatal rats was induced with angiotensinⅡ(Ang Ⅱ) stimulation. Before AngⅡ stimulation, the cultured rat cardiac myocytes were pretreated with atorvastatin at different concentrations(0.1, 1, and 10 μmol/L). The following parameters were evaluated: the myocyte surface area, 3H-leucine incorporation into myocytes, m RNA expressions of atrial natriuretic peptide, brain natriuretic peptide, matrix metalloproteinase 9, matrix metalloproteinase 2, and interleukin-1β, m RNA and protein expressions of the δ/β peroxisome proliferator-activated receptor(PPAR) subtypes. Results It was shown that atorvastatin could ameliorate Ang Ⅱ-induced neonatal cardiomyocyte hypertrophy in the area of cardiomyocytes, 3H-leucine incorporation, and the expression of atrial natriuretic peptide and brain natriuretic peptide markedly. Meanwhile, atorvastatin also inhibited the augmented m RNA level of several cytokines in hypertrophic myocytes. Furthermore, the down-regulated expression of PPAR-δ/β at both the m RNA and protein levels in hypertrophic myocytes could be significantly reversed by atorvastatin treatment. Conclusions Atorvastatin could improve AngⅡ-induced cardiac hypertrophy and inhibit the expression of cytokines. Such effect might be partly achieved through activation of the PPAR-δ/β pathway.
文摘Functional responses to angiotensin Ⅱ (AT-Ⅱ) were determined in aortic vascular smooth muscle cells (VSMCs) from experimental cirrhotic rats. Our data showed that AT-Ⅱ-stimulated extracellular acidification rate (ECAR), which was measured by Cytosensor microphysiometry, was significantly reduced in the aortic VSMCs from the cirrhotic rats as compared to those from the control animals. The ability of AT-Ⅱ to promote formation of inositol phosphates, the second messenger produced by the activation of Gq-coupled receptors, was also considerably suppressed in the cirrhotic VSMCs. Furthermore, the maximal p42/44 MAPK phosphorylation stimulated by AT-Ⅱ was significantly reduced in the cirrhotic VSMCs in contrast to that in the normal VSMCs. Taken together, our data clearly demonstrated that the functional responses to AT-Ⅱ was severely suppressed in aortic VSMCs in cirrhosis, indicating the impairment of general Gq-coupled receptor signaling and subsequent biological function in the cirrhotic VSMCs.
