Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The physiological effects of angiotensin II (Ang II) are mediated through specific AT(1) and AT(2) receptors. Tissue distribution and affinity of these receptors have been explored in binding studies, reverse transcriptase-polymerase chain reaction and in situ hybridisation. Sequencing has also demonstrated gene polymorphisms for both AT(1) and AT(2) receptors. Numerous potent nonpeptide antagonists of angiotensin converting enzyme or of AT receptors have been developed, thus providing a precise analysis of the physiology of the renin-angiotensin system. AT(1) receptors are widely expressed throughout adult tissues, while AT(2) receptors are mainly expressed in the fetus. Receptor density on the cell surface is regulated by multiple hormonal, cytokine and metabolic factors, and is thus profoundly affected by various pathological conditions, especially in the myocardium, kidney and blood vessels. To date, the precise molecular basis for these modifications has not been fully explained, although it may rely in part upon AT receptor gene polymorphisms, which could thus constitute increased risk factors for cardiovascular disease. AT(1) and AT(2) receptor expression is therefore influenced by both age and environmental specifications and is likely to be increased by a diet rich in salt or cholesterol, thus justifying the use of Ang II receptor antagonists in morbidity-mortality studies in high-risk patients.
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PMID:[Exploring AT(1) and AT(2) angiotensin II receptors in humans]. 1203 85

A major source of vascular smooth muscle cell (VSMC) superoxide is NAD(P)H oxidase. However, the molecular characteristics and regulation of this enzyme are unclear. We investigated whether VSMCs from human resistance arteries (HVSMCs) possess a functionally active, angiotensin II (Ang II)-regulated NAD(P)H oxidase that contains neutrophil oxidase subunits, including p22phox, gp91phox, p40phox, p47phox, and p67phox. mRNA expression of gp91phox homologues, nox1 and nox4, was also assessed in HVSMCs, human aortic smooth muscle cells, and rat VSMCs. HVSMCs were obtained from resistance arteries from gluteal biopsies of healthy subjects. gp91phox and nox4, but not nox1, were detected in HVSMCs. Nox1 and nox4, but not gp91phox, were expressed in human aortic smooth muscle cells and rat VSMCs. All NAD(P)H oxidase subunits were present in HVSMCs as detected by reverse transcriptase-polymerase chain reaction and immunoblotting. Ang II increased NAD(P)H oxidase subunit abundance. These effects were inhibited by cycloheximide. Acute Ang II stimulation (10 to 15 minutes) increased p47phox serine phosphorylation and induced p47phox and p67phox translocation. This was associated with NAD(P)H oxidase activation. In cells transfected with gp91phox antisense oligonucleotides, Ang II-mediated actions were abrogated. NADPH-induced superoxide generation was reduced by gp91ds-tat and apocynin, inhibitors of p47phox-gp91phox interactions. Our results suggest that HVSMCs possess a functionally active gp91phox-containing neutrophil-like NAD(P)H oxidase. Ang II regulates the enzyme by inducing phosphorylation of p47phox, translocation of cytosolic subunits, and de novo protein synthesis. These novel findings provide insight into the molecular regulation of NAD(P)H oxidase by Ang II in HVSMCs. Furthermore, we identify differences in gp91phox homologue expression in VSMCs from rats and human small and large arteries.
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PMID:Expression of a functionally active gp91phox-containing neutrophil-type NAD(P)H oxidase in smooth muscle cells from human resistance arteries: regulation by angiotensin II. 1206 24

Previous studies showed that aquaporin 2 (AQP2) is elevated in the kidney of the heart failure rat suggesting that an increased amount of AQP2 contributes to water retention in heart failure. We performed the present study to determine whether angiotensin II play a role in causing an increase in the expression of arginine vasopressin (AVP) V2 and AQP2 mRNA in the kidney of the cardiomyopathic hamster. The expression of AVP V2 and AQP2 mRNA in the inner medullary collecting duct (IMCD) was measured by competitive reverse transcriptase-polymerase chain reaction (RT-PCR) before and after treatment with an angiotensin-converting enzyme inhibitor, enalapril. Our results showed that the expression of AVP V2 (0.53 +/- 0.05 v 1.03 +/- 0.15 amol/microg of total RNA, P <.01) and AQP2 mRNA (0.027 +/- 0.002 v 0.036 +/- 0.002 amol/microg of total RNA, P <.05) in the IMCD of the cardiomyopathic hamster is upregulated. Treating the cardiomyopathic hamster with enalapril for 7 days negated the changes. In situ hybridization experiments confirmed the intensity of the signals for both AVP V2 and AQP2 mRNA was more intense in the IMCD of the cardiomyopathic hamster. Enalapril treatment reduced the signal intensity to a level comparable to the normal hamster. These results suggested that the increases in the expression of AVP V2 and AQP2 mRNA are mediated by angiotensin II.
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PMID:Upregulation of vasopressin V2 and aquaporin 2 in the inner medullary collecting duct of cardiomyopathic hamsters is attenuated by enalapril treatment. 1214 68

Transforming growth factor (TGF)-beta1 is important in fibrogenesis and has been involved in the pathogenesis of chronic allograft nephropathy (CAN). The angiotensinogen (AGT) gene encodes the only glycoprotein known to be a precursor of the vasopressor angiotensin II. Angiotensin II is also a growth factor and a profibrogenic cytokine. It mediates the induction of TGF-beta1. We studied the relationship among the intragraft expression of AGT, TGF-beta1, and CAN in stable renal transplant patients (RTP). We used a competitive quantitative reverse transcriptase-polymerase chain reaction (RT-PCR)-ELISA assay to identify intragraft amounts of AGT expression in RTP and correlated it with TGF-beta1 mRNA expression. We studied and performed kidney biopsies on 12 RTP with long-functioning grafts and 6 RTP in the immediate posttransplantation period (7 days) who had acute tubular necrosis as control. Histology was based on Banff working classification criteria. Total RNA was isolated from biopsy specimens. For RT-PCR-ELISA, we created heterologous RNA competitors that coamplified with the same primers as AGT and TGF-beta1. Six of 12 long RTP had proteinuria >1000 mg/24 hr and 6 had proteinuria <1000 mg/24 hr. The differences between Banff grades (P =0.03), AGT, and TGF-beta1 levels by RT-PCR-ELISA were statistically significant between both groups (106.2+/-60.7 vs. 34.1+/-11.9 pg/microg total RNA [P =0.01] and 5954+/-5612 vs. 436+/-517 transcripts/microg total RNA [P =0.01], respectively). The control group showed AGT levels of 25+/-12.2 pg/microg total RNA and TGF-beta1 levels of 228+/-111 transcripts/microg total RNA, significant only for the higher proteinuria group (P=0.01 and P=0.04, respectively). There was a correlation between AGT and TGF-beta1 in both groups (r=0.96, P=0.001). We showed a relationship between mRNA expression of AGT and TGF-beta1 in kidney transplant patients with different grades of CAN and proteinuria.
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PMID:Intragraft messenger RNA expression of angiotensinogen: relationship with transforming growth factor beta-1 and chronic allograft nephropathy in kidney transplant patients. 1235 92

This study aimed to search genes altered in expression after long-term treatment with the angiotensin II type 1 receptor (AT1) antagonist, CV-11974, in volume-overloaded hearts. Arteriovenous shunt was made between the common carotid artery and jugular vein in Japanese White rabbits. Shunt-operated rabbits were randomly treated with CV-11974 or vehicle for 6 weeks, starting 6 weeks after surgery. As controls, sham-operated rabbits were given vehicle. Total RNA was prepared from each left ventricular myocardium. Using differential display, we screened one cDNA encoding human beta-catenin, in which the expression was upregulated after CV-11974 administration in shunt rabbit hearts. Beta-catenin is a molecule that exists in the intercalated disks and also works in cytoplasm as a major component of Wnt signaling. We then examined mRNA expressions of beta-catenin and connexin43 by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The mRNA expressions of beta-catenin and connexin43 were markedly depressed in shunt-operated animals given vehicle compared with sham-operated animals (P < 0.01). These results suggest that downregulation of beta-catenin and connexin43 expression might be involved in the process of ventricular remodeling by volume overload. The RT-PCR also demonstrated that beta-catenin mRNA expression was significantly higher in shunt rabbits treated with CV-11974 than in those given vehicle (P < 0.05). These data suggest that volume overload may downregulate beta-catenin expression by an AT1 receptor-mediated pathway.
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PMID:Long-term treatment with angiotensin II type 1 receptor antagonist, CV-11974, restores beta-catenin mRNA expression in volume-overloaded rabbit hearts. 1243

Vascular endothelial growth factor (VEGF), produced predominantly by endothelial cells, is involved in angiogenesis and mitogenesis. Myofibroblasts (myoFb) are phenotypically transformed fibroblast-like cells found at the site of myocardial infarction. Since myoFb play a role in tissue repair/remodeling at the site of infarction, and express endothelin and angiotensin II (AngII), it was interesting to investigate whether myoFb express VEGF and its receptors de novo, and if the expression is influenced by vasoactive peptides. Primary cultures of myoFb were isolated from 4-week-old adult rat heart infarct were used in this study. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), utilizing primers designed to amplify known isoforms of VEGF revealed expression of two predominant forms, VEGF120 and VEGF164 and northern blot hybridization detected VEGF mRNA of 4.5 kb. VEGF actions are mediated via two major receptors, Flt-1 and KDR, and hence the expression of these receptors was investigated. Flt-1 and KDR expression in myoFb was detected by RT-PCR, RNA transcripts were confirmed by northern blot hybridization while western blot confirmed the presence of VEGF, Flt-1 and KDR proteins in myoFb. In this study AngII upregulated VEGF and Flt-1 expression in myoFb, but not KDR; this was mediated predominantly by AT1-receptor. We report for the first time that cardiac myoFb, isolated from the site of infarction express VEGF, its receptors, Flt-1 and KDR, with modulation of VEGF and Flt-1 expression by AngII. Thus, VEGF may contribute to tissue remodeling and angiogenesis at the site of infarction in an autocrine manner.
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PMID:Cardiac myofibroblasts: a novel source of vascular endothelial growth factor (VEGF) and its receptors Flt-1 and KDR. 1267 42

To examine the possible role of the bradykinin-NO system in the action of ACE inhibitors, we studied the effects of imidapril, an ACE inhibitor, on inflammatory vascular injury by using AT1a-receptor-deficient (AT1aKO) mice. A polyethylene cuff was placed around the femoral artery of AT1aKO mice and wild-type (WT; C57BL/6J) mice. Neointimal area in cross sections of the artery was measured 14 days after cuff placement. A low dose of imidapril (1 mg/kg per day), which did not affect blood pressure, was administered by gavage. Expression of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-alpha was detected by immunohistochemical staining and reverse transcriptase-polymerase chain reaction (RT-PCR) 7 days after the operation. Neointimal formation, vascular smooth muscle cell proliferation, and expression of MCP-1 and TNF-alpha were attenuated in the injured artery in AT1aKO mice compared with those in WT mice. Imidapril inhibited neointimal formation, DNA synthesis of vascular smooth muscle cells, and expression of MCP-1 and TNF-alpha in AT1aKO mice as well as in WT mice. In addition, imidapril increased tissue cGMP content after cuff placement. These inhibitory effects of imidapril were significantly reduced or abolished by a bradykinin receptor antagonist, Hoechst 140, or an NO synthase inhibitor, L-NAME, both in WT and AT1aKO mice. Treatment with imidapril did not change AT2 receptor and ACE expression detected by RT-PCR in the injured artery. These results indicate that not only blockade of angiotensin II production but also activation of the bradykinin-NO system plays an important role in the beneficial effects of imidapril on vascular remodeling.
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PMID:Important role of nitric oxide in the effect of angiotensin-converting enzyme inhibitor imidapril on vascular injury. 1296 79

Childhood survivors of cancer who are treated with anthacycline chemotherapy, such as doxorubicin (DOX), can develop late-onset cardiomyopathy years after chemotherapy. The mechanism(s) for progression of anthracycline cardiotoxicity to late cardiomyopathy is unknown. Because angiotensin II has been implicated in the progression of other cardiomyopathies, this investigation was undertaken to determine whether treatment with an angiotensinconverting enzyme (ACE) inhibitor, lisinopril, reduces the time-dependent effects of doxorubicin on cardiac gene expression and myocellular apoptosis. A single dose of saline (control) or doxorubicin (DOX treated; 2 mg/kg iv) was administered to rabbits. Control and DOX-treated groups were also subgrouped to receive lisinopril and designated as lisinopril or DOX + lisinopril, respectively (1 mg/kg/d oral), for 10 wk. Histopathology, as determined at the light and ultrastructural level, was consistent with a reduced number of cardiomyocytes relative to interstitial cells in the left ventricle (LV) of the DOX-treated group compared with control and DOX + lisinopril groups. Gene expression of the pro-atrial naturetic peptide (ANP), quantified by steady-state messenger ribonucleic acid (mRNA) levels with reverse transcriptase polymerase chain reaction (RT-PCR) and Southern blotting, increased approx 12-fold (n = 10; p < 0.05) in the LV of DOX-treated groups compared to control and DOX + lisinopril groups. Increased ANP mRNA expression following doxorubicin dosing was localized predominantly in ventricular myocytes by in situ hybridization. Deoxyribonucleic acid (DNA) fragmentation, determined by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling), was increased in both DOX-treated and DOX + lisinopril groups compared to the control group. Lisinopril prevented both late-onset increased ventricular ANP expression and subsequent DOX-induced myocyte loss. The authors speculate that these protective effects of lisinopril are related to reduced ANP expression and myocyte loss, the latter possibly mediated by effects on myocellular apoptosis.
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PMID:Effects of angiotensin-converting enzyme inhibitor on delayed-onset doxorubicin-induced cardiotoxicity. 1473 29

Among the mitogen-activated protein kinase (MAPK) family members, extracellular signal-regulated kinase (ERK) promotes cell proliferation or differentiation, whereas c-jun N terminal kinase (JNK) and p38 MAPK are thought to inhibit cell growth and induce apoptosis. The MAPK family may plays some role during kidney development, when large-scale proliferation and apoptosis have been observed to occur. Also, in this period, the renin-angiotensin system is markedly activated. We have demonstrated that angiotensin-converting enzyme inhibition in the developing rat kidney increases apoptosis and decreases cell proliferation, which may account for renal growth impairment. The aim of this study, therefore, was to examine the relationship between the MAPK family and renin-angiotensin system during neonatal renal development. Newborn rat pups were treated with enalapril (30 mg . kg(-1) . d(-1)) or normal saline for 7 d. Right kidneys of both groups were selected for immunohistochemical stains of MAPKs and activating transcription factor-2 (ATF-2), and left kidneys were selected for reverse transcriptase-PCR and immunoblot analysis of MAPKs, phospho-MAPKs, and ATF-2. To determine whether apoptosis is involved in the same tubules that highly expressed JNK and p38, we performed terminal deoxynucleotide transferase-mediated nick-end labeling stain for apoptotic cells and immunohistochemical stains for JNK-2, p38, and ATF-2 expression in the serial sections from the same kidney of the enalapril-treated group. In the enalapril-treated group, JNK-2, p38, phospho-JNK-2, phospho-p38, and ATF-2 protein expressions were significantly increased, and their immunoactivities were strongly detected in the proximal tubular epithelial cells in the cortex, compared with the control group. Especially JNK-2 and p38 expressions were highly activated and were spatially in accordance with the occurrence of apoptosis. ERK1/2 and phospho-ERK expressions were not changed by enalapril. These results suggest that the expressions of the MAPK family are modulated by angiotensin-converting enzyme inhibition in the developing kidney. JNK and p38 may be implicated to participate in angiotensin II-related intracellular signaling pathways of renal apoptosis in the developing kidney.
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PMID:Angiotensin-converting enzyme inhibition modulates mitogen-activated protein kinase family expressions in the neonatal rat kidney. 1553 46

We reported previously that insulin inhibits the stimulatory effect of high glucose on the expression of angiotensinogen (ANG) gene in both rat immortalized renal proximal tubular cells (IRPTCs) and non-diabetic rat renal proximal tubular cells (RPTCs), but has no effect in diabetic rat RPTCs. In the present study we investigated whether hyperglycaemia-induced resistance to the insulin-induced inhibition of expression of the ANG gene is mediated via the generation of reactive oxygen species (ROS) in RPTCs. Rat IRPTCs were cultured for 2 weeks in high-glucose (25 mM) or normal-glucose (5 mM) medium plus angiotensin II (Ang II) with or without a superoxide scavenger (tiron), or inhibitors of: NADPH oxidase (diphenylene iodinium, DPI), Ang II type 1 and 2 receptors (losartan and PD123319), angiotensin-converting enzyme (perindopril), protein kinase C (GF 109203X), or glutamine:fructose-6-phosphate amino-transferase (azaserine). Cellular generation of ROS, and ANG and renin mRNA levels were assessed by lucigenin assay and specific reverse transcriptase-PCR respectively. Phosphorylation of p44/42 mitogen-activated protein kinase (p44/42 MAPK) was evaluated by western blotting. Prolonged exposure of IRPTCs to high concentrations of glucose or Ang II evoked generation of ROS and resistance to the insulin-induced inhibition of expression of the ANG gene and of p44/42 MAPK phosphorylation. Co-incubation of IRPTCs with tiron, DPI, losartan, PD123319, perindopril, GF 109203X or azaserine prevented ROS generation, restoring the inhibitory action of insulin on ANG gene expression and on p44/42 MAPK phosphorylation. In conclusion, our studies demonstrate that blockade of both ROS generation and activation of the intrarenal renin-angiotensin system improves the inhibitory action of insulin on ANG gene expression in IRPTCs in conditions of high glucose.
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PMID:Reactive oxygen species blockade and action of insulin on expression of angiotensinogen gene in proximal tubular cells. 1559 Sep 80


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