Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neutral endopeptidase (NEP; enkephalinase, EC 3.4.24.11) is a cell membrane associated zinc metalloprotease, which cleaves peptides like atrial natriuretic peptide (ANP) on the amino-side of hydrophobic amino acids. Although NEP is mainly located in reabsorptive epithelia (kidney proximal tubule), it is also present in non-epithelial cells like neuronal cells. As the renal NEP cannot account for the entire ANP metabolism, other locations were postulated. The present experiments show its expression in endothelial cells (EC) from arterial (bovine pulmonary, porcine and human aorta) and venous (human umbilical, rabbit ear marginal) origins. Three different methods were used to demonstrate the presence of the protein and its mRNA: 1) NEP enzymatic activity was estimated using both a synthetic ([D-Ala2, Leu5] enkephalin) and a natural substrate (bradykinin). Using the synthetic substrate, the enzymatic activity in EC was completely blocked by thiorphan, a specific NEP inhibitor with an IC50 value in the nM range. In contrast, captopril, bestatin, GEMSA, inhibitors of angiotensin-converting enzyme, aminopeptidases and carboxypeptidases, respectively, were 10,000 times less active, revealing an inhibition profile similar to that of the purified enzyme. Bradykinin, a natural substrate of NEP, was in part metabolized by NEP, in presence of captopril, since 50% of the formation of the major metabolite bradykinin 1-7 was inhibited by thiorphan. 2) Immunoreactive NEP was detected on the plasma membrane of rabbit EC using a monoclonal antibody directed against the homologous renal enzyme. 3) NEP mRNA was detected by Northern blot analysis on rabbit EC as a major transcript of 3.9 kb. Reverse transcriptase PCR amplification showed the presence of a specific transcript in all EC tested. Therefore, endothelial NEP could play an important role in the inactivation of ANP, bradykinin and endothelins by its localization facing the circulating vasoactive peptides.
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PMID:[Identification and characterization of neutral endopeptidase in endothelial cells of arterial or venous origin]. 133 90

Neutral endopeptidase (NEP; enkephalinase, EC 3.4.24.11) is a cell membrane-associated zinc metalloprotease, which cleaves peptides like atrial natriuretic peptide (ANP) on the amino side of hydrophobic amino acids. Although NEP is mainly located in reabsorptive epithelia (kidney proximal tubule), it is also present in non-epithelial cells such as neuronal cells. As the renal NEP cannot account for the entire ANP metabolism, other locations were postulated. The present experiments show its expression in endothelial cells (EC) from arterial (bovine pulmonary, porcine, and human aorta) and venous (human umbilical, rabbit ear marginal) origins. Three different methods were used to demonstrate the presence of the protein and its mRNA. 1) NEP enzymatic activity was estimated using both a synthetic ([D-Ala2,Leu5]enkephalin) and a natural substrate (bradykinin). Using the synthetic substrate, the enzymatic activity in EC was completely blocked by thiorphan, a specific NEP inhibitor with an IC50 value in the nanomolar range. In contrast, captopril, bestatin, [2-guanidinoethylmercapto]succinic acid, inhibitors of angiotensin-converting enzyme, aminopeptidases, and carboxypeptidases, respectively, were 10,000 times less active, revealing an inhibition profile similar to that of the purified enzyme. Bradykinin, a natural substrate of NEP, was in part metabolized by NEP, in the presence of captopril, since 50% of the formation of the major metabolite bradykinin 1-7 was inhibited by thiorphan. 2) Immunoreactive NEP was detected on the plasma membrane of rabbit EC using a monoclonal antibody directed against the homologous renal enzyme. 3) NEP mRNA was detected by Northern blot analysis of rabbit EC as a major transcript of 3.9 kilobases. Reverse transcriptase polymerase chain reaction amplification showed the presence of a specific transcript in all EC tested. Therefore, endothelial NEP may play an important role in the inactivation of ANP, bradykinin, and endothelins by its localization facing the circulating vasoactive peptides.
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PMID:Identification and characterization of neutral endopeptidase in endothelial cells from venous or arterial origins. 162 99

The tissue kallikrein-kinin system is important in regulating cardiovascular and renal function, and dysregulation of the system has been implicated in heart and kidney pathologies. These findings suggest that if balance can be restored to the kallikrein-kinin axis, then associated disease progression may be attenuated. To test this hypothesis, recombinant adeno-associated virus (rAAV)-mediated human tissue kallikrein (HK) expression was induced in a rodent model of chronic renal failure involving 5/6 nephrectomy (nephrectomy plus 70% reduction of remaining kidney). rAAV-HK treatment attenuated the rise in blood pressure, glomerular sclerosis, and tubulointerstitial injury observed in this model. rAAV-HK treatment also attenuated renal function decline as measured by urinary microalbumin, osmolarity, and cGMP levels. Reverse transcriptase-polymerase chain reaction analysis showed that rAAV-HK-treated rats had higher levels of bradykinin receptor-2 (B(2)R) and dopamine receptor-1 mRNAs. In contrast, angiotensin II receptor-1, endothelin receptor-A, and vasopressin receptor-2 mRNAs were markedly downregulated in kidneys from HK-treated rats. Bradykinin induced similar changes in receptor levels and prevented transforming growth factor-beta(1)-induced tubulointerstitial fibrosis. The effects of bradykinin could be reversed with the B(2)R antagonist HOE-140. Together, these findings suggest that restoration of the kallikrein-kinin system reduces kidney injury and protects renal function in 5/6-nephrectomized rats via changes in the expression and activation of G protein-coupled receptors including B(2)R.
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PMID:Delivery of recombinant adeno-associated virus-mediated human tissue kallikrein for therapy of chronic renal failure in rats. 1840 47