Endothelin-converting Enzyme-1 Expression Research Articles

Angiotensin-converting enzyme inhibitor therapy prevents upregulation of endothelin-converting enzyme-1 in failing human myocardium

In this study, we investigated the role of the renin–angiotensin system in expression of the endothelin system in atrial myocardium of patients with congestive heart failure. Atrial myocardium of control patients without angiotensin-converting enzyme (ACE) inhibitor therapy and heart failure patients without or with ACE inhibitor therapy undergoing aorto-coronary bypass surgery was studied. Endothelin-converting enzyme-1 (ECE-1) expression and endothelin-1 peptide level was upregulated in myocardium of heart failure patients without ACE inhibition. ACE inhibitor therapy prevented upregulation of ECE-1 and endothelin-1 in failing myocardium. Prepro-endothelin-1 and endothelin receptor A expression were not affected by heart failure. Endothelin receptor B was downregulated in heart failure patients. Our data demonstrate an upregulation of ECE-1 mRNA expression in failing human myocardium. Inhibition of the renin–angiotensin system by ACE inhibitor treatment prevents upregulation of ECE-1, suggesting that angiotensin II regulates ECE-1 expression in vivo.

Competency of embryonic cardiomyocytes to undergo Purkinje fiber differentiation is regulated by endothelin receptor expression.

Purkinje fibers of the cardiac conduction system differentiate from heart muscle cells during embryogenesis. In the avian heart, Purkinje fiber differentiation takes place along the endocardium and coronary arteries. To date, only the vascular cytokine endothelin (ET) has been demonstrated to induce embryonic cardiomyocytes to differentiate into Purkinje fibers. This ET-induced Purkinje fiber differentiation is mediated by binding of ET to its transmembrane receptors that are expressed by myocytes. Expression of ET converting enzyme 1, which produces a biologically active ET ligand, begins in cardiac endothelia, both arterial and endocardial, at initiation of conduction cell differentiation and continues throughout heart development. Yet, the ability of cardiomyocytes to convert their phenotype in response to ET declines as embryos mature. Therefore, the loss of responsiveness to the inductive signal appears not to be associated with the level of ET ligand in the heart. This study examines the role of ET receptors in this age-dependent loss of inductive responsiveness and the expression profiles of three different types of ET receptors, ET(A), ET(B) and ET(B2), in the embryonic chick heart. Whole-mount in situ hybridization analyses revealed that ET(A) was ubiquitously expressed in both ventricular and atrial myocardium during heart development, while ET(B) was predominantly expressed in the atrium and the left ventricle. ET(B2) expression was detected in valve leaflets but not in the myocardium. RNase protection assays showed that ventricular expression of ET(A) and ET(B) increased until Purkinje fiber differentiation began. Importantly, the levels of both receptor isotypes decreased after this time. Retrovirus-mediated overexpression of ET(A) in ventricular myocytes in which endogenous ET receptors had been downregulated, enhanced their responsiveness to ET, allowing them to differentiate into conduction cells. These results suggest that the developmentally regulated expression of ET receptors plays a crucial role in determining the competency of ventricular myocytes to respond to inductive ET signaling in the chick embryo.

Endothelin-1 receptors and biosynthesis in the corpus luteum: Molecular and physiological implications

Endothelin-1 (ET-1), a 21-amino acid peptide was initially identified as a potent vasoconstrictor, ET-1 plays an important role in the female reproductive cycle: its quick ascent during luteal regression, ability to inhibit steroidogenesis in vitro and in vivo, combined with the observation that the luteolytic effects of prostaglandin F2α (PGF2α) were delayed by pretreatment with ET-1 receptors type A (ETA) antagonists suggest that this peptide functions as an important element of the luteolytic cascade. The observation that ETA receptor expression was inversely correlated with steroidogenesis in luteal cells; namely factors which stimulated steroidogenesis inhibited ETA receptor levels is also in accord with the inhibitory role of ET-1 in corpus luteum (CL) function. Contrary to the mature mid cycle CL, the CL of early cycle is refractory to PGF2α-induced luteolysis. PGF2α administered at early luteal phase (day 4 of the cycle) failed to increase luteal ET-1 gene expression or its ETA receptors. In contrast, both genes were markedly induced in mid cycle CL exposed to PGF2α. ET-1 gene is transcribed as prepro ET-1 (ppET-1) and the active form of peptide is derived from the inactive intermediate big ET-1, by endothelin-converting enzyme-1 (ECE-1), therefore alterations in mature ET-1 levels can be achieved by modulating the expression of ppET-1 and/or ECE-1. Analysis using in situ hybridization and enriched luteal cell subpopulations showed that both steroidogenic and endothelial cells of the CL expressed high levels of ECE-1 mRNA. The ppET-1 mRNA, on the other hand, was only expressed by resident endothelial cells, suggesting that luteal parenchymal and endothelial cells cooperate in the biosynthesis of mature bioactive ET-1. A significant, four-fold elevation in ECE-1 expression (mRNA and protein levels) occurred during the transition of the CL from early to mid luteal phase. This increase was accompanied by a significant rise in ET-1 peptide. Surprisingly however, ppET-1 mRNA levels remained similar during early and mid luteal phase. Collectively, these studies demonstrate that: (a) the various components of ET-1 system (ET-1/ECE-1/ETA) are dynamically and independently regulated during bovine luteal life span. (b) The CL becomes PGF2α-responsive only when both ppET-1 and ECE-1 genes are expressed at a level which enable an uninterrupted ET-1 biosynthesis.

Ontogeny of Endothelin-Converting Enzyme Gene Expression and Protein Content in the Ovine Fetal Lung

Endothelin 1 (ET-1) is a potent vasoconstrictor and smooth muscle comitogen that is produced by endothelin-converting enzyme 1 (ECE-1) in endothelium and smooth muscle of the vascular wall in adult pulmonary arteries. However, little is known about the role of ECE-1 in the fetal pulmonary circulation. The ET-1 protein content falls just prior to birth in the fetal lamb lung. We hypothesized that the expression of ECE-1 is developmentally regulated and that ECE-1 levels fall prior to birth. To test this hypothesis, we measured lung ECE-1 mRNA levels and protein content and determined the cellular localization of ECE-1 expression in lung tissues from fetal lambs between 70 and 140 days of gestation (term = 145 days), newborn lambs, and ewes. We found that ECE-1 mRNA expression and protein content were lower in the fetal lamb lung just prior to birth in comparison with the newborn lamb lung. Immunolocalization of ECE-1 protein showed expression of ECE-1 in the vascular endothelium but not in the vascular smooth muscle at all gestational ages. We conclude that ECE-1 is developmentally regulated and that ECE-1 is expressed in the vascular endothelium but not in the smooth muscle of the fetal pulmonary vasculature. We speculate that alterations in ECE-1 contribute to the changes in ET-1 levels during the perinatal period and that the majority of ET-1 produced in the fetal lamb pulmonary vasculature is produced by the vascular endothelium.

低酸素ラット大動脈内皮細胞におけるエンドセリン—1とエンドセリン変換酵素—1の発現性の変化

低酸素ラット大動脈内皮細胞におけるエンドセリン—1とエンドセリン変換酵素—1の発現性の変化

Enhanced expression of endothelin-1 and endothelin-converting enzyme-1 in acute hypoxic rat aorta.

Deeply anesthetized male Wistar rats were perfused by Hanks' balanced salt solution bubbled with either 95%air and 5%CO2 (normoxic group) or 95%N2 and 5%CO2 (hypoxic group) from the thoracic aorta for 30 min, and the isolated abdominal aortae from both groups were used for electron microscopy, immunocytochemistry of endothelin (ET)-1 and ET-converting enzyme (ECE)-1, and in situ hybridization of preproET-1 mRNA. A remarkable increase in the number of Weibel-Palade (WP) bodies, storage sites of ET-1 and ECE-1, occurred in the hypoxic group when compared to the normoxic group. Immunoreactivities for ET-1 and ECE-1, and signals for preproET-1 mRNA were seen along the endothelia of both groups, but the intensities were significantly elevated in the hypoxic group. The increase in the number of ECE-1 immunoreactive gold particles was noticed especially in WP bodies in the hypoxic group. These findings indicate the enhancement of preproET-1 synthesis in the aortic endothelial cells as well as the acceleration of ET-1 processing in increased WP bodies in such cells in an experimentally hypoxic condition of the rat aortae.

The mRNA Expression of Angiotensin and Endothelin System Members in Bovine Ovarian Follicles During Final Follicular Growth

Recent observations suggest that vasoactive peptides angiotensin II (Ang II) and endothelin-1 (ET-1) regulate ovarian functions. The aim of this study was to investigate mRNA expression by semi-quantitative RT-PCR for the members of the angiotensin system such as angiotensin converting enzyme (ACE), angiotensin type 1 and 2 receptors (AT1R and AT2R), and also for the members of the endothelin system such as ET-1, endothelin converting enzyme-1 (ECE-1), endothelin A and B receptors (ETR-A and ETR-B) in theca interna (TI) and granulosa cell (GC) compartments of bovine follicles during final follicular growth. A classification of follicles into five groups ( 0.5-5; >5-20; >20-180; >180 ng/ml) was performed according to the estradiol-17β (E) content of follicular fluid. For the angiotensin system, the mRNA expression of ACE in TI significantly increased with E content in preovulatory follicles. In contrast, the GC of follicles did not express ACE mRNA. The mRNA expression of AT1R and AT2R in TI and GC was consistently detected throughout the different follicular stages. For the endothelin system, mRNA expression of ECE-1 in TI and GC increased during final growth of follicles. The mRNA expression of ET-1 in TI decreased in large follicles, whereas in GC it was completely negative at all stages of the follicle. In TI, mRNA expression of both ETR-A and B was constant, while in GC the expression of ETR-A mRNA increased with follicular E content. In conclusion, it is clear from our results that distinct regulatory changes of mRNA expression for some members of the angiotensin and endothelin systems occur in mature follicles. Particularly, a significant increase in the mRNA expression of both ACE and ECE toward the final maturation of follicles suggests the possible modulatory roles of Ang II and ET-1 in supplying the optimal microenvironment of ovulatory follicles.

Distinct cellular localization and regulation of endothelin-1 and endothelin-converting enzyme-1 expression in the bovine corpus luteum: implications for luteolysis.

Endothelin-1 (ET)-1 within the corpus luteum (CL) is rapidly up-regulated during natural or PGF(2 alpha)-induced luteolysis; however, such an increase was not observed at early luteal stage, when the CL is refractory to PGF(2 alpha). The mature and active form of ET-1 is derived from the inactive intermediate peptide, big ET-1, by ET-converting enzyme (ECE)-1. This study therefore examined the developmental and cell-specific expression of ECE-1 in bovine CL. A significant, 4-fold, elevation in ECE-1 expression (mRNA and protein levels) occurred during the transition of the CL from early to midluteal phase. Analysis using in-situ hybridization and enriched luteal cell subpopulations showed that both steroidogenic and endothelial cells of the CL expressed high levels of ECE-1 mRNA; prepro ET-1 mRNA, on the other hand, was only expressed by resident endothelial cells. These data suggest that luteal parenchymal and endothelial cells may cooperate in the biosynthesis of mature bioactive ET-1. In the mature CL, ECE-1 mRNA increase occurred both in steroidogenic and endothelial cells and was accompanied by a significant rise in ET-1 peptide. However, in contrast to ECE-1, prepro ET-1 mRNA levels were similar in early and midluteal-phase CL. Low ECE-1 levels during the early luteal phase, restricting the production of active ET-1, may explain why the immature CL is able to withstand PGF(2 alpha)-induced luteolysis.

Distinct Cellular Localization and Regulation of Endothelin-1 and Endothelin-Converting Enzyme-1 Expression in the Bovine Corpus Luteum: Implications for Luteolysis

Distinct Cellular Localization and Regulation of Endothelin-1 and Endothelin-Converting Enzyme-1 Expression in the Bovine Corpus Luteum: Implications for Luteolysis

Transcriptional mechanism of protein kinase C-induced isoform-specific expression of the gene for endothelin-converting enzyme-1 in human endothelial cells.

Isoform-specific expression of endothelin-converting enzyme (ECE)-1, the major big endothelin-processing enzyme, is controlled by alternative promoters. Signaling pathways and transcriptional mechanisms of ECE-1 mRNA expression are largely unknown. To investigate ECE-1 isoform expression after protein kinase C (PKC) activation, we used phorbol 12-myristate 13-acetate (PMA) to stimulate primary cultured human umbilical vein endothelial cells and the related EA.hy926 cell line. ECE-1a mRNA was up-regulated (approximately 3-fold), whereas mRNA of alternative isoforms (b, c, and d) was unchanged, which was confirmed on the protein level. PMA effects on mRNA expression were suppressed by the PKC inhibitors H-7 and Calphostin C. Because increased ECE-1a expression was preceded by induction of the transcription factor Ets-1, we performed gel shift assays and demonstrated specific DNA/protein interactions involving the ETS binding motif GGAA. Luciferase reporter assays showed that PMA induced ECE-1a promoter activity about 2.5-fold in EA.hy926 cells. Similarly, coexpression of Ets-1 protein resulted in a dose-dependent increase in ECE-1a promoter activity (more than 8-fold). Using gel shift assays and mutation analysis, we identified two tandemly arranged Ets-1 binding sites (EBS) at -638 and -658, respectively, that are involved in transcriptional activation of the ECE-1a promoter by PMA or Ets-1. Moreover, we also found evidence for binding of a transcriptional repressor to EBS -638. The inhibitor of mitogen-activated protein kinase kinase, PD98059, inhibited PMA effects on ECE-1a mRNA expression and promoter activity, respectively. Our results provide the first detailed analysis of signaling pathways and transcriptional mechanisms involved in isoform-specific ECE-1 gene expression.

Thrombin suppresses endothelial nitric oxide synthase and upregulates endothelin-converting enzyme-1 expression by distinct pathways: role of Rho/ROCK and mitogen-activated protein kinase.

An imbalance of nitric oxide and endothelin plays an important role in cardiovascular disease. Thrombin exerts profound effects on endothelial function. The present study investigated the molecular mechanisms by which thrombin regulates endothelial nitric oxide synthase (eNOS) and endothelin-converting enzyme (ECE)-1 expression in human endothelial cells. Incubation of human umbilical vein endothelial cells with thrombin (0.01 to 4 U/mL) for 15 to 24 hours markedly downregulated eNOS and increased ECE-1 protein level in a dose-dependent manner. Thrombin also decreased eNOS mRNA and increased ECE-1 mRNA level. In mRNA stability assay, thrombin shortened the half-life of eNOS mRNA but not that of ECE-1 mRNA. Activation of protease-activated receptor 1 by the agonist (SFLLRN, 10 to 100 micromol/L) had no effect on eNOS expression but increased ECE-1 level as thrombin. Thrombin activated Rho A and extracellular signal-regulated kinase (ERK)1 and ERK2. Inhibition of Rho A by C3 exoenzyme (20 microgram/mL) and ROCK by Y-27632 (10 micromol/L) prevented the downregulation of eNOS expression by thrombin. Y-27632 also prevented the reduction in NOS activity induced by prolonged incubation with thrombin. On the other hand, inhibition of ERK1 and ERK2 activation by PD98059 (50 micromol/L) prevented the upregulation of ECE-1 expression by thrombin as well as the increase in ECE activity and ET-1 accumulation in the medium. Treatment of rat aorta with thrombin overnight impaired endothelium-dependent relaxations but not endothelium-independent relaxations. Thus, thrombin suppresses eNOS and upregulates ECE-1 expression via Rho/ROCK and ERK pathway, respectively. These effects of thrombin may be important for endothelial dysfunction in cardiovascular disease, particularly during acute coronary episodes.

Preeclamptic serum enhances endothelin-converting enzyme expression in cultured endothelial cells

Increased vascular sensitivity to vasoconstrictors, such as angiotensin II and epinephrine, is observed in preeclampsia (PE). Recently, it was suggested that abnormal endothelial function might contribute to the pathophysiologic changes in PE. We investigated vasoconstrictor (angiotensin II and epinephrine)-induced endothelin-1 (ET-1) release from human umbilical vein endothelial cells incubated with sera from women with PE compared with normotensive pregnant and nonpregnant women. Moreover, inositol 1,4,5-trisphosphate production and endothelin-converting enzyme (ECE) expression in human umbilical vein endothelial cells were also evaluated. There were no significant differences in ET-1 release without vasoconstrictors among the three groups (nonpregnant, normotensive pregnant, and PE). No significant differences in basal inositol 1,4,5-trisphosphate production and ECE expression without vasoconstrictors were detected among the three groups. Vasoconstrictor-induced ET-1 release was significantly increased by PE sera. No significant difference was detected in vasoconstrictor-induced inositol 1,4,5-trisphosphate production among the three groups. However, ECE expression after incubation with vasoconstrictor was significantly increased by PE sera. Our results suggest that ET-1 release from endothelial cells may contribute to the increased vascular sensitivity to vasoconstrictors observed in PE, and that vasoconstrictor-induced ET-1 release may be related to enhanced ECE expression.

Endothelin Converting Enzyme-1 Expression in Endometrial Adenocarcinomas

Endothelin-1 (ET-1) is a potent mitogen in various precursor tumor cells, including endometrial adenocarcinoma. It is proposed that ET-1 produced by endometrial adenocarcinoma may participate in the angiogenesis of this carcinoma in vivo. Endothelin converting enzyme-1 (ECE-1) is the key enzyme that synthesizes ET-1. In this study, we tried to demonstrate the expression of ECE-1 in endometrial carcinomas. Deparaffinized tissue sections from patients with endometrial adenocarcinoma were analyzed by immunohistochemistry for the presence of ECE-1. Our study showed that the expression of ECE-1 was markedly increased in 9 of 15 (60%) well-differentiated endometrial adenocarcinomas; in contrast, only 2 out of 10 (20%) control specimens showed a mild labeling. With new selective inhibitory molecules emerging, research is currently evaluating the possible inhibition of ECE-1 as an alternative approach for the treatment of endometrial as well as other carcinomas.

Regulatory effect of experimental diabetes on the expression of endothelin receptor subtypes and their gene transcripts in the rat adrenal gland.

Endothelins (ETs) mediate paracrine control of vascular tone and secretion of steroids and catecholamines in the adrenal gland through two ET receptor subtypes, ETA and ETB. The differential distribution and function of these subtypes are responsible for the multiplicity of endothelin actions in this tissue. This study examines the regulatory effects of experimental diabetes on the gene expression, subtype specificity and localization of ET receptor subtypes, ET isopeptides, and endothelin-converting enzyme-1 (ECE-1) in the rat adrenal gland. The densities, pharmacological properties and distribution of ET receptor subtypes ETA and ETB in adrenal glands from streptozotocin-induced diabetic, insulin-treated diabetic and age-matched control rats were investigated, using radioligand receptor binding and autoradiographic techniques. The gene expression of ETA and ETB receptors ET-1, ET-3 and ECE-1 was evaluated using relative multiplex reverse transcription/PCR. The induction of diabetes caused a marked reduction in body weight but no significant change in adrenal gland size. The density of ET receptors was significantly increased in the diabetic rat adrenal gland, mainly because of an increase in the expression of ETB receptors. Insulin treatment normalized the diabetes-induced changes in the expression levels of ET receptor subtypes to control levels. The expression level of ET-1 mRNA was up-regulated, whereas ET-3 mRNA was down-regulated in the diabetic adrenal gland compared with the controls. The ECE-1 mRNA level in the adrenal gland was not altered by the induction of diabetes. Autoradiographic studies showed that ETA and ETB are the predominant receptor subtypes in the adrenal medulla and cortex respectively. These results suggest that ETA and ETB receptors are differentially distributed and regulated in the diabetic rat adrenal gland.

Selective upregulation of endothelin converting enzyme-1a in the human failing heart

Background: Increased plasma levels of endothelin-1 (ET-1) occur with congestive heart failure (CHF), but the components of the enzymatic activation of ET-1 in the myocardium remain to be defined. Accordingly, endothelin converting enzyme-1 (ECE-1) activity and expression in normal and failing heart were examined. Methods and Results: Left ventricular (LV) tissue samples were obtained from patients undergoing heart transplantation because of dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) and from normal donor hearts. The gene expression of ET-1 precursor and ECE-1a was upregulated 4- and 3-fold, respectively, in the failing heart. ECE-1 activity (fmol/mg protein per hour) was augmented from 2,291 ± 257 in normal tissue samples to 5,507 ± 666 in DCM samples and to 7,435 ± 682 in ICM samples ( P < .05). Phosphoramidon and a specific ECE-1 inhibitor, FR901533, inhibited ECE-1 activity by over 90%. However, inhibitors of neutral endopeptidase (thiorphan) and matrix metalloproteases (batimistat) did not affect the conversion of big ET-1 to ET-1. Conclusions: This study showed that the biosynthetic pathway of ET-1 is activated in LV myocardium in the failing heart, and the myocardial processing of big ET-1 is highly specific for ECE-1.

Enhancement of Endothelin Converting Enzyme and Endothelin Receptor Subtypes in Human Myocardium with Congestive Heart Failure

Abstract Endothelin-1 (ET-1) is a potent endothelial cell-drived vasoconstrictive peptide which is increased in congestive heart failure (CHF). ET-1 is converted from its precursor big ET-1 by activation of endothelin converting enzyme (ECE). ET-1 binding to ET-A receptor in vascular smooth muscle cells stimulates vasoconstriction and binding to ET-B receptor in vascular endothelial cells mediates vasodilation. In previous studies, we and others demonstrated that plasma ET-1 was significantly increased in congestive heart failure. However, the presentation and localization of endothelin converting enzyme and endothelin receptors (ET-A and ET-B) in human cardiac tissue with and without heart failure remain unclear. Therefore, the current study was designed to investigate the expression and localization of endothelin receptors and endothelin converting enzyme in human myocardium in the absence or presence of congestive heart failure. Human atrial tissues (n=6) were obtained from normal subjects and end-stage CHF patients during cardiac transplantation. The expression of ECE, ET-A and ET-B were determined by immunohistochemical staining (IHCS).

Suppression of endothelin-converting enzyme-1 by sucralfate, a factor in gastric mucosal resistance to indomethacin injury in rats

Aims: Endothelin-1 (ET-1), a key mediator of inflammatory processes associated with gastric mucosal injury, is a potent vasoactive peptide produced from a biologically inactive big ET-1 by the action of endothelin-converting enzyme-1 (ECE-1). In this study, we investigated gastric mucosal expression of ECE-1 during a 16 h course of inflammatory responses associated with gastric mucosal damage caused by indomethacin, and evaluated the effect of pretreatment with an antiulcer agent, sucralfate, on this process. ___TAGSTART___BR___TAGEND___Methods: The experiments were conducted with groups of rats pretreated intragastrically with sucralfate at 200 mg/kg or vehicle, followed 30 min later by an intragastric dose of indomethacin at 60 mg/kg, and at different time (2, 4, 8, and 16 h) intervals, their stomachs were used for macroscopic and biochemical assessments. ___TAGSTART___BR___TAGEND___Results: Examination of gastric mucosa from the control animals revealed that, within 2 h, indomethacin caused multiple hemorrhaging lesions, the extent of which reached a maximum after 4 h and was accompanied by a 4-fold enhancement in the expression of ECE-1 activity, and a marked elevation in ET-1 (4.5-fold), TNF-α (11.3-fold) and apoptosis (29.9-fold). Pretreatment with sucralfate produced within 2 h a 59.7% reduction in the extent of mucosal damage caused by indomethacin, while an 81% reduction in lesion was observed after 16 h. This effect of sucralfate was accompanied by a significant reduction in the mucosal expression of ECE-1, the activity of which declined by 57.3% within 2 h following sucralfate, while a 38.4% decline in the indomethacin-induced expression of ECE-1 was attained after 16 h. Moreover, the reduction in the severity of damage following pretreatment with sucralfate was reflected at the end of 16-h period in a 47.4% decrease in the mucosal expression of TNF-α, 25.1% decline in ET-1, and a 38.9% decline in apoptosis. ___TAGSTART___BR___TAGEND___Conclusions: The results demonstrate that gastric mucosal injury by indomethacin is associated with up-regulation of ECE-1 expression, which leads to the enhancement of ET-1 production, induction of TNF-α, and triggering of apoptotic events that exacerbate the inflammatory process. Our findings also show that sucralfate protection against gastric mucosal injury caused by indomethacin involves the suppression of the mucosal ECE-1 activity.

Suppression of Endothelin-Converting Enzyme-1 during Buccal Mucosal Ulcer Healing: Effect of Chronic Alcohol Ingestion

Among the factors affecting the efficiency of soft oral tissue healing is endothelin-1 (ET-1), a potent vasoactive peptide produced from a biologically inactive big ET-1 by the action of endothelin-converting enzyme-1 (ECE-1). We investigated the expression of ECE-1 during buccal mucosal ulcer healing in rats maintained for 5 weeks on alcohol containing or control diet. The mucosal activity of ECE-1, characterized by sensitivity to phosphoramidon, was associated with microsomal fraction and showed an elevated (3.1-fold) level in the alcohol diet group. Moreover, the ulcer onset in the alcohol group was reflected in a 39% greater expression of ECE-1 activity, and was accompanied by a 1.4-fold greater increase in TNF-α and a 2.5-fold greater enhancement in epithelial cell apoptosis. While in both groups the ulcer healing was associated with a decrease in buccal mucosal expression of ECE-1, as well as a decline in TNF-α and apoptosis, the changes were significantly slower in the alcohol diet group and manifested by a 40% delay in healing. Thus, chronic alcohol ingestion leads to up-regulation of ECE-1 expression, induction of TNF-α, and triggering apoptotic events that delay the mucosal repair.

Temporospatial expression of endothelin converting enzyme-1 in acute and chronic liver injury and fibrogenesis

Temporospatial expression of endothelin converting enzyme-1 in acute and chronic liver injury and fibrogenesis

Induction of Endothelin-Converting Enzyme-1 in Gastric Mucosal Injury by Idomethacin

Endothelin-1 (ET-1) is a 21-amino acid vasoactive peptide produced from a 39-amino acid biologically inactive peptide, big ET-1, by the action of endothelin-converting enzyme-1 (ECE-1). We investigated gastric mucosal expression of ECE-1 during a 16 h course of inflammatory responses associated with gastric mucosal injury caused by indomethacin. The extent of gastric mucosal damage reached a maximum 4 h following the drug, and was accompanied by a 3.9-fold enhancement in the expression of ECE-1 activity and a significant elevation in ET-1 (4.5-fold), TNF-α (11.3-fold), and apoptosis (29.9-fold). A 37.2% decrease in the severity of lesion 16 h following the drug was associated with a 44.5% reduction in the mucosal expression of ECE-1 activity and a decline in TNF-α (64%), ET-1 (65.2%), and apoptosis (72.3%). The results demonstrate that gastric mucosal injury by indomethacin is associated with up-regulation of ECE-1 expression, which leads to the enhancement of ET-1 production, induction of TNF-α, and triggering apoptotic events that disrupt gastric mucosal homeostasis.