Animals ; Humans ; Ligands ; Polymorphism, Genetic ; Receptor Cross-Talk ; physiology ; Receptor, Angiotensin, Type 1 ; physiology ; Receptor, Angiotensin, Type 2 ; genetics ; physiology

OBJECTIVETo analyze the expression of angiotensin II (ANG II) receptor and apoptosis in myocardium in rats of endotoxemia.

METHODSModel of endotoxemia was induced by intraperitoneal injection with lipopolysaccharide (LPS) 10 mg/kg in male Wistar rats and saline was injected into control group. The rats were killed at 2 h or 6 h after saline (control) or LPS . Expression of the correlation factors related to apoptosis of Bcl-2, Bax, AT1 and AT2 receptor in myocardial tissue were detected with immunohistochemistry (IHC), and changes of myocardial cells apoptosis was detected by the method of TUNEL. The gene expression of AT1 and AT2 receptor was examined by RT-PCR. The pathological changes of myocardial tissue were observed by electron microscope.

RESULTSCompared with control group , the expression of AT1 and AT2 receptor were significantly decreased, especially in 6 h group; and the expression of Bcl-2 and Bax were decreased, the ratio of Bcl-2/Bax had the downtrend as well as the apoptosis of myocardial cells.

CONCLUSIONInterfered by LPS, the down regulation of AT1 and AT2 receptor expression has the negative relation with apoptosis of myocardial cells, this result indicated that down regulation of AT1 and AT2 receptor expression maybe related to cardiac functional impairment, which maybe help us to find a new protective path to prevent myocardial damage induced by systemic inflammatory.

Animals ; Apoptosis ; Endotoxemia ; metabolism ; Male ; Myocytes, Cardiac ; cytology ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; metabolism ; Receptor, Angiotensin, Type 2 ; metabolism

OBJECTIVETo characterize if irbesartan regulates vascular inflammatory gene expression profiles related to atherosclerosis in EA.hy926 cells.

METHODSHuman umbilical vein endothelial cell line EA.hy926 cultured in vitro was incubated with irbesartan (1×10(-6) mol/L) for 24 h. The total RNA was extracted from the cells for gene expression profiling. The DAVID Gene Functional Classification Tool was used to analyze the disease- and function-related genes in the cells. Real-time quantitative polymerase chain reaction (RT-PCR) was used to verify the genes showing differential expression after irbesartan treatment. The protein levels of angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R) were tested by Western blotting.

RESULTSCompared with the control cells, 56 genes were found to show marked changes following irbesartan treatment, including 39 up-regulated and 17 down-regulated genes. Disease analysis suggested that these genes were related to such diseases as coronary atherosclerosis, myocardial infarction, and colorectal cancer. Eight genes, namely MMP2, PTGS2, PECAM1, SELP, SELL, CYP1A1, MMRN1, and HSPA1A, were involved in atherosclerosis and myocardial infarction. Verification by RT-PCR produced a result consistent with the gene array result. AT1R was down-regulated while AT2R up-regulated in irbesartan-treated cells.

CONCLUSIONIrbesartan regulates the inflammatory gene expressions related to atherosclerosis in EA.hy926 cells. These inflammatory factors may promote destabilization of atherosclerotic plaque possibly in relation to AT2R overexpression.

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Atherosclerosis ; genetics ; pathology ; prevention & control ; Biphenyl Compounds ; pharmacology ; Cell Line ; Cytoprotection ; Gene Expression Profiling ; Human Umbilical Vein Endothelial Cells ; drug effects ; pathology ; Humans ; Inflammation ; genetics ; Receptor, Angiotensin, Type 1 ; genetics ; Receptor, Angiotensin, Type 2 ; genetics ; Tetrazoles ; pharmacology

BACKGROUNDMany studies have suggested that angiotensin II (Ang II) and its receptors may be involved in the development of asthma. However, the expression of angiotensin II receptors (AGTR) is not clear in the lung tissue of chronic asthmatics. This study was designed to determine the relationship between airway remodeling, dysfunction and the expression of AGTRs in a rat model of asthma.

METHODSRats were sensitized with ovalbumin (OVA) for 2 weeks. Sixty minutes before an inhalation challenge, the rats were pretreated either with valsartan (15, 30, 50 mg x kg(-1) x d(-1)) or saline intragastrically. Then the rats received an OVA challenge for 30 alternative days. Acetylcholine (Ach)-induced bronchoconstriction was measured after the final antigen challenge. White cell counts in bronchoalveolar lavage fluid (BALF) and morphological changes in the airways were then assessed. The levels of transforming growth factor-beta 1 (TGF-beta(1)) and platelet-derived growth factor (PDGF) in BALF were detected by ELISA. The levels of AGTR1 and AGTR2 mRNA and protein in lung tissues were measured by RT-PCR and Western blotting.

RESULTSAGTR1 mRNA and protein levels in repeatedly OVA-challenged rats were significantly increased as compared with negative controls. The AGTR1 mRNA expression versus white cell counts of BALF and airway wall thickness (mainly in small airways) in lungs of chronic antigen-exposed rats were positively correlated. Valsartan decreased the level of AGTR1 in repeatedly OVA-challenged rats. However, AGTR2 mRNA and protein levels in the OVA-challenged rats and high-dose valsartan-treated rats (50 mg x kg(-1) x d(-1)) were also increased. Valsartan significantly decreased inflammatory cell accumulation and attenuated Ach-evoked bronchoconstriction in repeatedly antigen-challenged rats. Valsartan also decreased allergen-induced structural changes in rat airway (including total airway wall thickness and smooth muscle area) and the levels of TGF-beta(1) and PDGF in BALF.

CONCLUSIONSAGTR1 expression is potentially associated with airway remodeling and dysfunction in asthma. Ang II and AGTR1 may participate in airway inflammation and airway remodeling of chronic antigen-exposed rats. Valsartan, a AGTR1 antagonist, could inhibit AGTR1 expression and partially inhibits structural airway changes as well as airway inflammation in chronic OVA-exposed rats.

Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Angiotensin Receptor Antagonists ; Animals ; Asthma ; chemically induced ; genetics ; metabolism ; Blotting, Western ; Bronchoalveolar Lavage Fluid ; chemistry ; Enzyme-Linked Immunosorbent Assay ; Gene Expression ; drug effects ; Lung ; drug effects ; metabolism ; pathology ; Male ; Ovalbumin ; Platelet-Derived Growth Factor ; metabolism ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism ; Receptors, Angiotensin ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tetrazoles ; pharmacology ; Transforming Growth Factor beta1 ; metabolism ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

BACKGROUNDObstructive sleep apnea is a frequent medical condition consisting of repetitive sleep-related episodes of upper air ways obstruction and can lead to hypertension. Ang II type 1 receptor (AT1R) played important roles in hypertension since it binds with Ang II, controlling salt-water and blood pressure homeostasis. This study explores rat aorta AT1R expression during intermittent hypoxia (IH) and the signaling pathways involved.

METHODSA rat model and a cell model used a BioSpherix-OxyCycler A84 system and a ProOx C21 system respectively. The arterial blood pressure was recorded by a Nihon Kohden Polygraph System. Immunohistochemic was used to focus and analyze the expression of AT1R in rat aorta. Real-time PCR and Western blotting were used to explore the signaling pathways that participated in AT1R expression.

RESULTSIn this study, we found that chronic intermittent hypoxia (CIH) induced AT1R transcription which increased the blood pressure in rat aorta compared to normoxia and to sustained hypoxia. The AT1R protein expression in the aorta was similar to the real-time PCR results. We explored the signaling mechanisms involved in the AT1R induction in both rat aorta and the aortic endothelial cells by real-time PCR and Western blotting. Compared to normoxia, CIH increased ERK1 mRNA transcription but not ERK2 or p38MAPK in the aorta; whereas sustained hypoxia (SH) upregulated ERK2 but not ERK1 or p38MAPK mRNA. In cells, IH induced AT1R expression with ERK1/2 phosphorylation but reduced p38MAPKs phosphorylation, whereas SH induced only ERK1/2 phosphorylation. The ERK1/2 inhibitor PD98059 attenuated the IHinduced AT1R increase but the p38MAPK inhibitor SB203580 did not.

CONCLUSIONSOur results indicate that CIH induced the elevation of rat blood pressure and aorta AT1R expression. Moreover, AT1R expression in IH and sustained hypoxia might be regulated by different signal transduction pathways, highlighting a novel regulatory function through ERK1/2 signaling in IH.

Animals ; Aorta ; metabolism ; Blood Pressure ; physiology ; Hypoxia ; genetics ; physiopathology ; MAP Kinase Signaling System ; genetics ; physiology ; Male ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism

OBJECTIVETo identify single nucleotide polymorphisms (SNP) of the angiotensin II type 2 receptor (AGTR2) gene, and to determine whether the AGTR2 polymorphisms are associated with essential hypertension in a male Chinese population.

METHODSDirect DNA sequencing was performed in 20 subjects. 96 male hypertensive patients and 107 normal controls were included to assess the contribution of the SNP of AGTR2 gene to hypertension.

RESULTSSeven SNP of the AGTR2 gene were identified, of which 4 were reported for the first time. A case-control study including two polymorphisms (A1675G and T1334C) showed a significant increase in the A1675 allele frequency among male hypertensive subjects as compared with normotensive subjects (49.0% vs 34.6%, P < 0.05).

CONCLUSIONThe AGTR2 A1675G polymorphism might be involved in the development of essential hypertension in male Chinese.

Asian Continental Ancestry Group ; genetics ; Gene Frequency ; Humans ; Hypertension ; genetics ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Receptor, Angiotensin, Type 2 ; genetics

OBJECTIVETo investigate the effect of astragaloside IV (As IV) on the activation of rennin-angiotensin system in rats with pressure-overload induced cardiac hypertrophy.

METHODLeft ventricle hypertrophy was induced by abdominal aorta banding between bilateral renal aortas for 12 weeks. Rats were given astragaloside IV 1.0 mg x kg(-1) and 3.3 mg x kg(-1) for 12 weeks, respectively. After treatment, the left ventricular mass index (LVMI)was calculated by morphometry methods. Plasma and cardiac tissue angiotensin II, and plasma aldosterone were measured by ELISA method. Gene expressions of ACE, AT1 and AT2 in cardiac tissue were detected by real time PCR. Protein expressions of AT1 and AT2 in cardiac tissue were detected by Western blot.

RESULTCompared with model rats, LVMI was decreased by astragaloside IV treatment. Biochemical results indicated that the contents of angiotensin II in plasma and cardiac tissue as well as aldosterone in plasma were all increased in abdominal aorta banding rats comparing with sham-operated rats, then, decreased by astragaloside IV treatment. Gene expressions of cardiac ACE was downregulated by astragaloside IV, however, gene and protein expressions of cardiac AT2 were upregulated by astragaloside IV. Both elevated gene and protein expressions of AT1 were not attenuated by astragaloside IV.

CONCLUSIONExcessive activated rennin-angiotensin system in rats with pressure-overload induced cardiac hypertrophy is inhibited by astragaloside IV treatment.

Aldosterone ; blood ; Angiotensin II ; blood ; metabolism ; Animals ; Blood Pressure ; physiology ; Cardiomegaly ; drug therapy ; Enzyme-Linked Immunosorbent Assay ; Hypertrophy, Left Ventricular ; drug therapy ; metabolism ; Male ; Peptidyl-Dipeptidase A ; genetics ; Polymerase Chain Reaction ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; genetics ; Receptor, Angiotensin, Type 2 ; genetics ; Renin-Angiotensin System ; drug effects ; Saponins ; therapeutic use ; Triterpenes ; therapeutic use

Angiotensin II Type 1 Receptor Blockers ; administration & dosage ; Animals ; Coronary Angiography ; Coronary Restenosis ; prevention & control ; Coronary Vessels ; pathology ; Drug Delivery Systems ; Immunohistochemistry ; Rabbits ; Receptor, Angiotensin, Type 1 ; analysis ; Receptor, Angiotensin, Type 2 ; analysis ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Stents ; Tetrazoles ; administration & dosage ; Valine ; administration & dosage ; analogs & derivatives ; Valsartan

We determined the relationship between the progression of immunoglobulin A nephropathy (IgAN) and the A1818T polymorphism in intron 2 of Angiotensin II type 2 receptor (AT2R) gene, which might play protective roles in the pathogenesis of IgAN. Patients with biopsy-proven IgAN were recruited from the registry of the Progressive REnal disease and Medical Informatics and gEnomics Research (PREMIER) which was sponsored by the Korean Society of Nephrology. A1818T polymorphism of AT2R gene was analyzed with PCR-RFLP method and the association with the progression of IgAN, which was defined as over 50% increase in baseline serum creatinine level, was analyzed with survival analysis. Among the 480 patients followed for more than 10 months, the group without T allele had significantly higher rates of progression of IgAN than the group with T allele (11.4% vs. 3.9%, p=0.024), although there were no significant differences in the baseline variables such as initial serum creatinine level, the degree of proteinuria, and blood pressure. In the Cox's proportional hazard model, the hazard ratio of disease progression in the patients with T allele was 0.221 (95% confidence interval for Exp(B): 0.052-0.940, p=0.041) compared to that of without T allele. In conclusion, A1818T polymorphism of AT2R gene was associated with the progression of IgAN.
Alleles ; Creatinine/blood ; Disease Progression ; Genotype ; Glomerulonephritis, IGA/ethnology/*genetics ; Humans ; Korea ; Models, Genetic ; Models, Statistical ; *Polymorphism, Genetic ; Polymorphism, Restriction Fragment Length ; *Polymorphism, Single Nucleotide ; Receptor, Angiotensin, Type 2/*genetics ; Time Factors ; Treatment Outcome

OBJECTIVETo investigate the effect of interferon regulatory factors (IRFs) on neointimal formation after vascular injury in the mouse, and its possible mechanism.

METHODSVascular injury was induced by polyethylene cuff placement around the left femoral artery of IRF-1-deficient mice and C57BL/6J mice. The mRNA expressions of IRF-1, IRF-2, angiotensin II type 2 (AT2) receptor, interleukin-1 beta converting enzyme (ICE), inducible nitric oxide synthase (iNOS) were detected by RT-PCR and immunohistochemical staining.

RESULTSNeointimal formation after vascular injury was significantly greater in IRF-1-deficient mice than that in C57BL/6J mice (P<0.05). In contrast, TUNEL-positive nuclei to total nuclei in the neointima and media in vascular smooth muscle cell (VSMC) in the injured artery significantly attenuated in IRF-1-deficient mice compared to C57BL/6J mice (P<0.05). The expressions of AT2 receptor as well as pro-apoptotic genes such as ICE and iNOS in C57BL/6J mice were up-regulated in response to vascular injury, but this upregulation was attenuated in IRF-1-deficient mice.

CONCLUSIONSOur results suggest that IRF-1 induces VSMC apoptosis and inhibits neointimal formation after vascular injury at least partly due to the upregulation of AT2 receptor, ICE and iNOS expressions. These results indicate that IRF-1 exerts an inhibitory effect on neointimal formation through the induction of apoptosis in VSMCs.

Animals ; Apoptosis ; physiology ; Caspase 1 ; genetics ; metabolism ; Femoral Artery ; anatomy & histology ; pathology ; Interferon Regulatory Factor-1 ; genetics ; metabolism ; Interferon Regulatory Factor-2 ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Muscle, Smooth, Vascular ; cytology ; metabolism ; pathology ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; Platelet Endothelial Cell Adhesion Molecule-1 ; genetics ; metabolism ; Receptor, Angiotensin, Type 2 ; genetics ; metabolism ; Tunica Intima ; pathology ; physiology