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)

Vascular endothelin (ET)-1 is upregulated in several forms of salt-induced hypertension. It is unclear to what extent these effects are primary or secondary to endothelial damage. We hypothesized that a high-sodium diet (HNa) increases vascular ET-1 production independent of arterial blood pressure changes. We investigated the effect of chronic HNa with and without ET(A) blockade on circulating and aortic ET-1 protein levels as well as aortic expression of ET-1 and ET(A) messenger RNA (mRNA) in inbred Wistar-Kyoto (WKY) and congenic ET(B)-deficient rats. Comparing WKY rats fed a low-sodium diet (LNa) with those fed HNa for 3 weeks, aortic wall ET-1 protein is significantly increased in response to HNa (331 +/- 43 pg/g tissue for LNa vs. 557 +/- 34 pg/gm tissue for HNa). HNa also increased aortic wall ET-1 mRNA levels by 40%, as determined by quantitative reverse transcriptase polymerase chain reaction. We then compared rats chronically treated with the ET(A)-selective antagonist, ABT-627, while receiving either LNa or HNa. There were no differences in arterial blood pressure (mean arterial pressure 89 +/- 1 mm Hg for WKY on LNa; 90 +/- 3 for WKY on HNa; 91 +/- 2 for ET(B)-deficient/ABT-627-treated on HNa) or heart rate. However, aortic wall ET-1 protein levels were 4-fold higher in the HNa group. Further, HNa increased aortic wall ET-1 mRNA (approximately 1.5- to 3-fold) and ET(A) mRNA (approximately 2- to 7-fold), independent of activation of ET(B). Therefore, the expression of ET-1 mRNA by the aortic wall is increased in response to chronic high dietary sodium in WKY rats in the absence of changes in arterial blood pressure.
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PMID:Chronic high-sodium diet increases aortic wall endothelin-1 expression in a blood pressure-independent fashion in rats. 1674 Oct 4

Pulmonary hypertension (PH) usually develops secondary to left ventricular (LV) dysfunction; therefore, it is also called retrograde PH. To investigate our hypothesis that PH is at least partially reversible, as in some congenital heart diseases, in a rat model we investigated whether release of constriction could attenuate pulmonary vascular remodeling and change the expression of endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). We used rats with LV dysfunction produced by an ascending aortic banding. In this study, there were four groups enrolled: 4-weeks banded (AOB(1-28); n = 7), 7-weeks banded (AOB(1-49); n = 7), debanded groups (AOB(1-28)/DeB(29-49); n = 7), and rats receiving a sham operation (n = 7). Subsequently, there was significant attenuation of medial hypertrophy in pulmonary arterioles and reversal of PH in the AOB(1-28)/DeB(29-49) group (sham, 19 +/- 1.3 mm Hg; AOB(1-28), 31 +/- 2.7 mm Hg; AOB(1-49), 32 +/- 2.7 mm Hg; and AOB(1-28)/DeB(29-49), 20 +/- 1.3 mm Hg). PreproET-1 mRNA and eNOS mRNA were measured by competitive reverse transcriptase (RT) polymerase chain reaction (PCR), and eNOS was measured by Western blotting. Compared with the banded groups, debanding significantly decreased pulmonary preproET-1 mRNA, pulmonary ET-1 (sham, 210 +/- 12 pg/g protein; AOB(1-28), 242 +/- 12 pg/g protein; AOB(1-49), 370 +/- 49 pg/g protein; and AOB(1-28)/DeB(29-49), 206 +/- 1.9 pg/g protein), and plasma ET-1 levels (sham, 10.1 +/- 1.5 pg/ml; AOB(1-28), 13.4 +/- 2.0 pg/ml; AOB(1-49), 15.4 +/- 2.0 pg/ml; and AOB(1-28)/DeB(29-49), 10.3 +/- 0.9 pg/ml protein). Debanding could not, however, alter pulmonary eNOS, eNOS mRNA, or cGMP. These findings suggest that pulmonary vascular remodeling, increased pulmonary arterial pressure, and upregulation of ET-1 gene expression are all reversible. We infer that it is the upregulated gene expression of ET-1, not eNOS, that is closely related to the development of the PH secondary to 4 weeks of aortic banding.
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PMID:The effects of debanding on the lung expression of ET-1, eNOS, and cGMP in rats with left ventricular pressure overload. 1674 Oct 30

Endothelin (ET)-1 is an autocrine/paracrine growth factor or an antiapoptotic factor in human cancers, and blockade of ET-1 receptors can sensitize human tumor cells to apoptosis. The role of the ET-1 axis in the proliferation and/or apoptosis of melanoma cells and in their response to the alkylating agent, dacarbazine (DTIC), used in clinical treatment of human melanoma were investigated in five human melanoma cell lines obtained form surgical resection specimens. Melanoma cells expressed the messenger RNAs (mRNAs) for the components of the ET-1 axis. ET-1 binding was mediated by ET(B) but was inhomogeneous among melanoma cells. Exogenous ET-1 did not induce human melanoma cell proliferation. Bosentan, a dual ET(A/B)-receptor antagonist, decreased melanoma cell viability and DNA synthesis and induced melanoma cell apoptosis in defined human melanoma cells. Bosentan potentiated Fas ligand-induced apoptosis only in one melanoma cell line. Variants of ET(B)were determined using reverse transcriptase (RT) polymerase chain reaction (PCR) and primers spanning the whole sequence of the ET(B)gene. ET(B)variants were demonstrated only in one of the five cell lines, corresponding to the absence of ET-1 binding by these cells. Bosentan did not inhibit the effects of alkylating agents, and the effects of bosentan and alkylating agents were additive in melanoma cells. In conclusion, exogenous ET-1 is not a growth factor for human melanoma cells, but blockade of ET receptors decreases proliferation, induces apoptosis, and potentiates the effects of anticancer agents in defined melanoma cells, suggesting that combination therapy of ET-receptor antagonists with alkylating agents may improve their efficacy.
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PMID:Targeting the endothelin axis in human melanoma: combination of endothelin receptor antagonism and alkylating agents. 1674 Oct 59

We used cDNA microarray analysis of RNA extracted from normal, dysplastic, and cancerous cervical tissues to identify the changes in gene expression during the procession from normal to cancerous cervical epithelial cells. We found the expression of 5 genes in cancerous cervical epithelial cells that were not found in normal cervical epithelial cells, among which were lymphoid-restricted membrane protein, protease serine 2, WD repeat domain 59, thyrotropin-releasing hormone degrading enzyme, and the endothelin-3 growth factor. We then analyzed the expression levels of endothelin growth factors 1, 2, and 3 (ET-1, ET-2, and ET-3) and their receptors A and B (ETR-A and ETR-B) by reverse transcriptase-polymerase chain reaction in 3 cervical cancer cell lines and by immunohistochemical staining in cervical normal, dysplastic, and cancer tissues. ET-1, ET-2, and ET-3 growth factor levels were detectable in the maturing layer of cervical epithelium but not in the germinal layer. All 3 growth factors (ET-1, ET-2, and ET-3) were detected in the cytoplasm of the maturing normal cervical epithelial cells. In addition, there were decreased levels of ET-3 and increased levels of ET-1, ET-2, ETR-A, and ETR-B in cancerous cervical epithelial cells compared with normal cervical epithelial cells. These results suggest that the reduction of ET-3 growth factor levels may be important in the transition from normal to cancerous cervical epithelium.
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PMID:Endothelin-3 growth factor levels decreased in cervical cancer compared with normal cervical epithelial cells. 1744 67

Recent studies in our laboratory have demonstrated that angiotensin (ANG) II and endothelin (ET) 1 up-regulate the expression of arginine vasopressin V(2) receptor in the inner medullary collecting duct (IMCD) of the rat. The present studies were performed to explore the interaction between ANG II and ET-1 in up-regulating the expression of arginine vasopressin V(2) receptor in the IMCD of the rat. Two sets of studies were done. In the first set of studies, rat IMCD tissue was isolated and incubated with ANG II in combination with ET(A) or ET(B) antagonist. In the second set of experiments, rat IMCD tissue was incubated with ET-1 with ANG receptor antagonist saralasin. Tissue samples were then analyzed by means of quantitative reverse transcriptase polymerase chain reaction and Western blotting. The ANG II treatment resulted in increased V(2) messenger RNA (mRNA) from control level of 138 +/- 12 amol/microg of total RNA to 385 +/- 63 amol/microg of total RNA (P < .01). The ANG II/ET(A) treatment resulted in no significant decrease in V(2) mRNA expression (319 +/- 59 amol/microg of total RNA), whereas ET-1/ET(B) antagonist and ET-1/ET(A)/ET(B) antagonist treatments resulted in reducing V(2) mRNA to control levels of 214 +/- 25 and 176 +/- 22 amol/microg of total RNA, respectively. The ET-1 treatment increased V(2) mRNA expression from control level of 221 +/- 25 amol/microg of total RNA to 383 +/- 43 amol/microg of total RNA (P < .02). The ET-1-induced increase in V(2) mRNA expression was significantly reduced to control level (210 +/- 36 amol/microg of total RNA) after saralasin treatment. Western blotting revealed that changes in protein expression in the different treatment conditions were comparable with changes in V(2) mRNA expression. These data suggested that the up-regulation of V(2) receptor induced by ANG II and ET-1 is mediated by both vasoconstricting hormones. These 2 systems interact in up-regulating the expression of V(2) receptors in the kidney.
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PMID:Interaction between endothelin and angiotensin II in the up-regulation of vasopressin messenger RNA in the inner medullary collecting duct of the rat. 1788 47

Induction of heme-oxygenase (HO) is an important cellular defense mechanism against oxidative and inflammatory insults. We analyzed the effects of the HO inducer, heme-arginate, on the phospholipase C (PLC)/inositol-triphosphate (IP(3)) pathway in the mesenteric arterioles of uninephrectomized (UnX) deoxycorticosterone acetate (DOCA)-salt hypertensive rats, which is a volume-overload model characterized by elevated endothelin (ET-1) and mineralocorticoid-induced oxidative/inflammatory insults. Our study included the following groups: (A) controls [(i) surgery-free Sprague-Dawley (SD) rats, (ii) UnX-Sham, (iii) UnX-Salt (0.9% NaCl+0.2% KCl) and (iv) UnX-DOCA)]; (B) UnX-DOCA-salt hypertensive rats; (C) UnX-DOCA-salt+heme-arginate; (D) UnX-DOCA-salt+heme-arginate+chromium mesoporphyrin (CrMP), the HO inhibitor; (E) UnX-DOCA-salt+CrMP (F); SD+heme-arginate, (G) UnX-DOCA-salt+vehicle dissolving heme-arginate and CrMP and (H) normal-SD+heme-arginate. Quantitative reverse transcriptase PCR, western blot, enzyme immunoassay and spectrophotometric analyses were used. Heme-arginate enhanced mesenteric arteriole HO-1, HO activity, cyclic guanosine monophosphate (cGMP) and anti-oxidants including bilirubin, ferritin, superoxide dismutase with potentiation of the total anti-oxidant capacity. Correspondingly, oxidative/inflammatory mediators such as 8-isoprostane, nuclear-factor kappaB (NF-kappaB) and ET-1 were markedly reduced. Furthermore, heme-arginate suppressed PLC activity, attenuated IP(3) and reduced resting intracellular calcium. The effects of heme-arginate were nullified by the HO inhibitor, with aggravation of oxidative/inflammatory insults. In heme-arginate-treated SD rats, the HO system was potentiated to a lesser magnitude and the suppression of ET-1, PLC, IP(3) and NF-kappaB were less accentuated, suggesting greater selectivity of HO against the ET-1-PLC-IP(3)-NF-kappaB destructive axis in the pathological condition of mineralocorticoid-induced hypertension. Given that ET-1 stimulates PLC and IP(3), which in turn activates NF-kappaB, the concomitant reduction of ET-1, PLC, IP(3) and NF-kappaB alongside the corresponding decline of resting intracellular calcium may account for the reduction of blood pressure and attenuation of oxidative/inflammatory injury by heme-arginate.
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PMID:Heme-arginate suppresses phospholipase C and oxidative stress in the mesenteric arterioles of mineralcorticoid-induced hypertensive rats. 2020 87

Endothelin (ET)-1 is a potent vasoconstrictor peptide involved in the derangement of respiratory mechanics during endotoxic shock. We measured the kinetics of pulmonary mRNA expression of the key components of the ET system [i.e., ET-1, ET-converting enzyme (ECE), and ETA and ETB receptors] by quantitative real-time reverse transcriptase-polymerase chain reaction in a swine model of endotoxic shock (0, 1, 2, 3, and 4 h of continuous LPS infusion at 40 microg/kg/hour; sham group, 4 hour saline infusion). A significant increase in mRNA expression levels was observed for ET-1 in LPS-treated piglets; the increase began as early as 1 hour. In contrast, no significant variations were observed for the ECE, ETA, or ETB genes. Small gene expression differences observed with respect to our previous results suggest a possible effect of the anesthesia or surgical protocol on ET system regulation.
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PMID:Pulmonary kinetic expression of the endothelin system in a swine model of endotoxic shock. 2043 71


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