Cardiac remodeling is a common pathological manifestation of various end-stage cardiovascular diseases, which leads to myocardial diastolic and systolic dysfunction, low ejection fraction which cannot meet the needs of systemic tissue and organ metabolism, and ultimate progress into heart failure. Excessive activation of the classical renin angiotensin system (RAS), which is the angiotensin-converting enzyme-angiotensin II-type 1 angiotensin II receptor axis (ACE2-Ang II-AT1R axis), plays a key role in the pathological process of cardiac remodeling and heart failure. Angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axis [ACE2-Ang (1-7)-Mas axis] is an endogenous negative regulatory pathway of classical RAS, which can reduce its harmful effects. ACE2 is a monocarboxypeptidase that can hydrolyse Ang II and produce Ang (1-7), which has cardio-protective effects. Ang (1-7), via endogenous receptor Mas, plays the role of vasodilating, anti-proliferation and anti-differentiation, anti-fibrosis, anti-thrombosis and reversing myocardial remodeling. In recent years, with increasingly growing studies on the ACE2-Ang (1-7)-Mas axis, there are more understanding about their metabolic characteristics and mechanism of action. This article describes the role of ACE2 and Ang (1-7) in cardiac remodeling and heart failure and the related mechanisms, and discusses the potential benefits by regulating ACE2 activity and Ang (1-7) levels in clinical and experimental studies, hopefully providing potential therapeutic strategies.
Angiotensin I/metabolism* ; Heart Failure ; Humans ; Peptide Fragments/metabolism* ; Ventricular Remodeling

The purpose of this study was to compare the vasodilating effects of angiotensin-(1-7) [Ang-(1-7)] on the different vessels and to clarify its mechanisms by using relaxing responses of preconstricted vascular rings. The results showed: (1) Ang-(1-7) dose-dependently induced vasorelaxation in all the vessels studied. However, there is apparent heterogeneity in the responsiveness of vessels from different origin. (2) The Ang-(1-7)-induced vasorelaxation was endothelium dependent and largely mediated by NO system. (3) The vasodilator action of Ang-(1-7) was not mediated by AT1 or AT2 receptor subtypes. It is suggested that the Ang-(1-7)-induced vasorelaxation is endothelium dependent by some other unclarified angiotensin receptor subtypes and is largely mediated by NO system.
Angiotensin I ; pharmacology ; physiology ; Animals ; Endothelium, Vascular ; drug effects ; metabolism ; Female ; Male ; Nitric Oxide ; biosynthesis ; Peptide Fragments ; pharmacology ; Rabbits ; Receptor, Angiotensin, Type 1 ; physiology ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the effects of insulin like growth factor-1 (IGF-1) on cell viability and tissue factor (TF) in angiotensin II (Ang II) induced vascular endothelial cells and to investigate its mechanisms.

METHODS10(-6) mol/L Ang II was added to human vascular endothelial cells (HUVECs) culture media alone or 30 min after pretreatment with IGF-1 (0.1 microg/ml , 0.5 microg/ml, 2.5 microg/ml). Cell viability and AngII type 1 receptor (AT1-R) mRNA were evaluated after 24 h incubation with AngII. At the optimum concentration of IGF-1 affecting cell viability, the time dependent manner for 12 - 48 h incubation with Ang II was evaluated. TF, NOS and NO were investigated after 24 h incubation with Ang II. In addition, NO synthase inhibitor Nomega-nitro-1-arginine methylester(L-NAME) was added 30 min before addition of IGF-1 and Ang II, and cell viability, TF, AT1-R mRNA, NOS and NO were evaluated after 24 h incubation.

RESULTS(1) Ang II induced a decrease in cell vitality, an upregulation of AT1-R mRNA, an increase in TF, and a decrease in the activity of NOS and content of NO. (2) Pretreatment with IGF-1 significantly inhibited the decreased cell viability and upregulation of AT1-R mRNA. IGF-1 at 0.5 microg/ml showed the most obvious effects. This effect of cell viability recovery was in a time dependent manner during 12 -48 h. (3) IGF-1 also inhibited the increased content of TF, the decreased activity of NOS and the decreased content of NO. (4) The beneficial effects of IGF-1 on cultured endothelial cells were completely abolished by L-NAME.

CONCLUSIONIGF-1 pretreatment could enhance the ang II injured cell viability and anti-thrombosis capacity, and the protective effects may be related to activation of NOS-NO signaling pathway which inhibited AT1-R.

Angiotensin II ; pharmacology ; Cell Survival ; drug effects ; Cells, Cultured ; Endothelial Cells ; drug effects ; metabolism ; physiology ; Humans ; Insulin-Like Growth Factor I ; pharmacology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Thromboplastin ; metabolism

To explore the angiotensin peptide [Ang (1-7)]-mediated inhibition of Ang II in human hepatic stellate cells (HSCs) and determine the involvement of the ACE2-Ang (1-7)-Mas axis. The human HSC line, LX2, was used in all experiments, and divided into control (unstimulated) and Ang II-stimulated (10-6 mol/L) groups. The Ang II-stimulated cells were further divided among several pre-treatment (prior to Ang II) groups: ROCK-inhibited (Y27632 blocking agent, 10-6 mol/L); irbesartan-inhibited (AT-1 receptor antagonist, 10-6 mol/L); and Mas receptor-inhibited (A779 Mas receptor antagonist, 10-6 mol/L). To explore the potential inhibitory effects of various Ang family members, the Ang II-stimulated and pre-treated LX2 cells were exposed to Ang (1-7) (10-6 mol/L) for 24 h. Western blot, reverse transcription-polymerase chain reaction (RT-PCR), and QuantiGene assay were used to assess changes in protein and mRNA expression levels of RhoA, ROCK, and connective tissue growth factor (CTGF). Compared with the control group, Ang II-stimulated cells showed significantly increased levels of RhoA protein (0.337+/-0.074 vs. 0.870+/-0.093), ROCK2 mRNA (0.747+/-0.061 vs. 0.368+/-0.023), and CTGF mRNA (0.262+/-0.007 vs. 0.578+/-0.028) (all, P less than 0.01). Pre-treatment with irbesartan or Y27632 eliminated these responses. Ang (1-7) inhibited the Ang II-stimulated up-regulation of RhoA, ROCK, and CTGF. Ang (1-7) can inhibit the Ang II-stimulated up-regulation of RhoA, ROCK and CTGF in hepatic stellate cells, indicating that the ACE2-Ang (1-7)-Mas axis, an important branch of the renin-Ang-aldosterone system is involved in the occurrence and development of liver fibrosis.
Angiotensin I ; pharmacology ; Angiotensin II ; pharmacology ; Cells, Cultured ; Connective Tissue Growth Factor ; metabolism ; Hepatic Stellate Cells ; drug effects ; metabolism ; Humans ; Peptide Fragments ; pharmacology ; RNA, Messenger ; genetics ; Signal Transduction ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

The present study was aimed to investigate the role and mechanism of glutaminolysis of cardiac fibroblasts (CFs) in hypertension-induced myocardial fibrosis. C57BL/6J mice were administered with a chronic infusion of angiotensin II (Ang II, 1.6 mg/kg per d) with a micro-osmotic pump to induce myocardial fibrosis. Masson staining was used to evaluate myocardial fibrosis. The mice were intraperitoneally injected with BPTES (12.5 mg/kg), a glutaminase 1 (GLS1)-specific inhibitor, to inhibit glutaminolysis simultaneously. Immunohistochemistry and Western blot were used to detect protein expression levels of GLS1, Collagen I and Collagen III in cardiac tissue. Neonatal Sprague-Dawley (SD) rat CFs were treated with 4 mmol/L glutamine (Gln) or BPTES (5 μmol/L) with or without Ang II (0.4 μmol/L) stimulation. The CFs were also treated with 2 mmol/L α-ketoglutarate (α-KG) under the stimulation of Ang II and BPTES. Wound healing test and CCK-8 were used to detect CFs migration and proliferation respectively. RT-qPCR and Western blot were used to detect mRNA and protein expression levels of GLS1, Collagen I and Collagen III. The results showed that blood pressure, heart weight and myocardial fibrosis were increased in Ang II-treated mice, and GLS1 expression in cardiac tissue was also significantly up-regulated. Gln significantly promoted the proliferation, migration, mRNA and protein expression of GLS1, Collagen I and Collagen III in the CFs with or without Ang II stimulation, whereas BPTES significantly decreased the above indices in the CFs. α-KG supplementation reversed the inhibitory effect of BPTES on the CFs under Ang II stimulation. Furthermore, in vivo intraperitoneal injection of BPTES alleviated cardiac fibrosis of Ang II-treated mice. In conclusion, glutaminolysis plays an important role in the process of cardiac fibrosis induced by Ang II. Targeted inhibition of glutaminolysis may be a new strategy for the treatment of myocardial fibrosis.
Rats ; Mice ; Animals ; Rats, Sprague-Dawley ; Angiotensin II/pharmacology* ; Fibroblasts ; Mice, Inbred C57BL ; Fibrosis ; Collagen/pharmacology* ; Collagen Type I/metabolism* ; RNA, Messenger/metabolism* ; Myocardium/pathology*

OBJECTIVETo investigate the effect of tanshinone II(A) on the expression of different components in the renin-angiotensin system of left ventricles of renal hypertensive rats.

METHODThe renal hypertension model was established in rats by the two-kidney-one-clip (2K1C) method. In the experiment, all of the rats were randomly divided into four groups (n = 15 per group) before the operation: the sham-operated (Sham) group, the hypertensive model (Model) group, the low-dose tanshinone II(A) group and the high-dose tanshinone II(A) group. At 5 week after the renal artery narrowing, the third and fourth groups were administered with 35 mg kg(-1) x d(-1) and 70 mg x kg(-1) x d(-1) of tanshinone II(A), respectively. The blood pressure in rats was determined by the standard tail-cuff method in each week after the operation. After the drug treatment for 8 weeks, all the rats were put to death, and their left ventricles were separated to determine the ratio of left ventricle weight to body weight (LVW/BW), the myocardial collagen content, and the expressions of different components in myocardial RAS, including angiotensin converting enzyme (ACE), angiotensin converting enzyme 2 (ACE2), angiotensin 1-type receptor (AT1R), Mas receptor mRNA expression and angiotensin II (Ang II) and angiotensin (1-7) [Ang (1-7)] content.

RESULTCompared with the sham group, the hypertensive model group exhibited a markable increase in the content of Ang II and Ang (1-7) and the mRNA expressions of ACE, ACE2, AT1R and Mas (P < 0.01). However, the treatment with tanshinone II(A) showed the does dependence, inhibited left ventricle hypertrophy, decreased myocardial Ang II content and the mRNA expression of ACE and AT, R in renal hypertensive rats (P < 0. 01) , further increased the myocardial Ang (1-7) content and the mRNA expression of ACE2 and Mas (P < 0.01) , but without any change in the blood pressure of hypertensive rats.

CONCLUSIONThe treatment with tanshinone II(A) could inhibit left ventricle hypertrophy of renal hypertensive rats. Its mechanism may be partially related to the expression of different components in the renin-angiotensin system for regulating myocardial tissues.

Angiotensin I ; genetics ; metabolism ; Angiotensin II ; genetics ; metabolism ; Animals ; Blood Pressure ; drug effects ; Diterpenes, Abietane ; administration & dosage ; Heart Ventricles ; drug effects ; metabolism ; Humans ; Hypertension ; drug therapy ; genetics ; metabolism ; physiopathology ; Male ; Peptide Fragments ; genetics ; metabolism ; Peptidyl-Dipeptidase A ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Renin ; genetics ; metabolism ; Renin-Angiotensin System ; drug effects

OBJECTIVETo observe the effect of Chinese herbs for stasis removing and collaterals dredging (CHSRCD) upon angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas axis in the renal cortex of diabetic nephropathy rats.

METHODSTotally 89 male Sprague-Dawley rats were randomly divided into the blank control group (C group, n=22), the high-glucose high-fat control group (H group, n=10), and the streptozotocin (STZ)-injecting group (n=57). The diabetes rat model (n=50) was induced by feeding high-glucose high-fat diet in combination with intraperitoneal injection of STZ, which were further divided into the model group (M group, n=24), the irbesartan group (I group, n=13), and the CHSRCD (Z group, n=13). Rats in I and Z groups were intragastrically fed with suspension of irbesartan and CHSRCD, once daily for 16 weeks. Equal volume of drinking water was administrated to rats in the rest groups. Blood glucose and 24 h urine protein quantitation were tested at four time points. And the mRNA expression of ACE2 and Mas at various time points was detected by Real-time PCR, immunohistochemical assay, and Western blot. Quantitative analyses of ACE2 and Mas protein expression were performed at the end of week 16.

RESULTSCompared with the C group, blood glucose increased in the H and M groups (P < 0.01). It was higher in the H group (P < 0. 01). 24 h urine protein quantitation at different time points increased in the M group, and it was higher than that in the H group (P < 0.05). Compared with the M group, 24 h urine protein quantitation decreased at the end of week 8 in the I group, and at the end of week 8 and 16 in the Z group (P < 0.05). It was lower in the Z group than in the I group at the end of week 16 (P < 0.05). Compared with the C and H groups, the expression of ACE2 mRNA in the renal cortex was lower in the M group at the end of week 16 (P < 0.01). Compared with the M group, it was higher in the Z group (P < 0. 01). There was no statistical difference in the expressions of Mas mRNA at the end of week 16 between the C group and the M group (P > 0.05). It was lower in the M group than in the H group (P < 0.05). It was higher in the Z group than in the M group (P < 0.05), and higher than in the I group (P < 0.05). The expression of ACE2 and Mas protein in the M group decreased as time went by. The expression quantitation of ACE2 and Mas protein at the end of week 16 was lower in the M group than in the C group (P < 0.05). Compared with the M group, ACE2 expression of the Z group and Mas of the I and Z groups increased more significantly (P < 0. 05).

CONCLUSIONCHSRCD could play a role in renal protection for diabetic nephropathy rats by up-regulating the mRNA and protein expression of ACE2 and Mas, promoting the ACE2-Ang-(1-7)-Mas axis, and lowering urinary protein.

Angiotensin I ; metabolism ; Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Nephropathies ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Kidney Cortex ; metabolism ; Male ; Peptide Fragments ; metabolism ; Peptidyl-Dipeptidase A ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; metabolism

OBJECTIVETo explore the effects of adrenomedullin (ADM) on Angiotensin II (AngII)-induced collagen synthesis in cultured rat vascular adventitial fibroblasts.

METHODSRat vascular adventitial fibroblasts were cultured in vitro. ADM produced and secreted from adventitia in the presence of AngII was detected by radioimmunoassay, type I, III collagen contents in adventitia fibroblasts were measured by ELISA and the expressions of TGFbeta1 and MMP-2 were determined by RT-PCR and Western blotting.

RESULTSAngII significantly induced ADM secretion in adventitial fibroblasts in a dose-dependent manner. These effects could be reduced by 45%, 3% and 46%, through pre-treatment with Losartan, PD123319 or both, respectively for 30 min in culture medium. The AngII-induced type I, III collagen secretion in adventitial fibroblasts was significantly reduced by AMD in a dose-dependent manner, (P < 0.01) while ADM agonist ADM(22 - 52) significantly potentiated the effect of AngII; ADM also reduced AngII-induced expression of TGFbeta1 at mRNA and protein levels in a dose-dependent manner. AngII reduced the expression of MMP-2 at mRNA and protein levels in adventitial fibroblasts and these effects could be reversed by AMD (10(-8) mol/L).

CONCLUSIONAngII stimulated ADM secretion in adventitia fibroblasts, ADM in turn can inhibit AngII-induced type I, III collagen synthesis in adventitial fibroblasts probably by downregulating the TGFbeta1 expression and upregulating MMP-2 expression. ADM therefore served as an antifibrotic factor in vascular remodeling process.

Adrenomedullin ; metabolism ; Angiotensin II ; metabolism ; Animals ; Cells, Cultured ; Collagen Type I ; biosynthesis ; Extracellular Matrix ; metabolism ; Fibroblasts ; metabolism ; Gene Expression Regulation ; Male ; Matrix Metalloproteinase 2 ; metabolism ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Transforming Growth Factor beta ; metabolism

OBJECTIVE: Silicosis, caused by inhalation of silica dust, is the most serious occupational disease in China and the aim of present study was to explore the protective effect of Ang (1-7) on silicotic fibrosis and myofibroblast differentiation induced by Ang II. METHODS: HOPE-MED 8050 exposure control apparatus was used to establish the rat silicosis model. Pathological changes and collagen deposition of the lung tissue were examined by H.E. and VG staining, respectively. The localizations of ACE2 and α-smooth muscle actin (α-SMA) in the lung were detected by immunohistochemistry. Expression levels of collagen type I, α-SMA, ACE2, and Mas in the lung tissue and fibroblasts were examined by western blot. Levels of ACE2, Ang (1-7), and Ang II in serum were determined by ELISA. Co-localization of ACE2 and α-SMA in fibroblasts was detected by immunofluorescence. RESULTS: Ang (1-7) induced pathological changes and enhanced collagen deposition in vivo. Ang (1-7) decreased the expressions of collagen type I and α-SMA and increased the expressions of ACE2 and Mas in the silicotic rat lung tissue and fibroblasts stimulated by Ang II. Ang (1-7) increased the levels of ACE2 and Ang (1-7) and decreased the level of Ang II in silicotic rat serum. A779 enhanced the protective effect of Ang (1-7) in fibroblasts stimulated by Ang II. CONCLUSION Ang (1-7) exerted protective effect on silicotic fibrosis and myofibroblast differentiation induced by Ang II by regulating ACE2-Ang (1-7)-Mas axis.
Actins ; metabolism ; Angiotensin I ; blood ; pharmacology ; therapeutic use ; Angiotensin II ; blood ; Animals ; Animals, Newborn ; Cell Differentiation ; drug effects ; Cells, Cultured ; Collagen Type I ; metabolism ; Disease Models, Animal ; Lung ; metabolism ; pathology ; Myofibroblasts ; drug effects ; Peptide Fragments ; blood ; pharmacology ; therapeutic use ; Peptidyl-Dipeptidase A ; metabolism ; Rats, Wistar ; Silicosis ; metabolism ; pathology ; prevention & control

AIMTo study the effect of angiotensin-(1-7) on the kidney of diabetic rats by observing the mRNA expression of PDGF and TGF-beta1.

METHODSSD rats were divided into three groups: Group C (uni-nephrectomy control group), Group D (diabetic model control group), Group T (Ang-(1-7) treated group). We evaluated blood glucose,urea nitrogen, creatinine and urine albumin excretion respectively, studied the renal morphology by light microscope, and detected the gene expression of PDGF, TGF-beta1 in renal tissue by RT-PCR technique.

RESULTSThere was significant difference between the group D and T about the RW/BW, renal morphology, the total urine protein and the mRNA expression of PDGF and TGF-beta1.

CONCLUSIONAng-(1-7) can relieve the renal process of diabetic rats.

Angiotensin I ; pharmacology ; Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Nephropathies ; metabolism ; Kidney ; metabolism ; pathology ; Male ; Peptide Fragments ; pharmacology ; Platelet-Derived Growth Factor ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta1 ; genetics ; metabolism