Raoch V, Martinez-Miguel P, Arribas-Gomez I, Rodriguez-Puyol M, Rodriguez-Puyol D, Lopez-Ongil S. The peptidase inhibitor CGS-26303 increases endothelin converting enzyme-1 expression in endothelial cells through accumulation of big endothelin-1.
Br J Pharmacol 2007;
152:313-22. [PMID:
17643133 PMCID:
PMC2042959 DOI:
10.1038/sj.bjp.0707398]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE
CGS-26303 inhibits endothelin converting enzyme (ECE)-1 more specifically than phosphoramidon. We have studied the effect of CGS-26303 on ECE-1 expression in bovine aortic endothelial cells.
METHODS
ECE-1 activity and big endothelin (ET)-1 levels were measured by ELISA, ECE-1 expression using western and northern blot and promoter activity using transfection assays.
KEY RESULTS
ECE-1 activity was completely inhibited by CGS-26303 25 microM and phosphoramidon 100 microM. CGS-26303 and phosphoramidon, though not thiorphan, a neutral endopeptidase (NEP) inhibitor, stimulated ECE-1 expression in cells (maximal effect at 16 h, 25 microM). Cycloheximide abolished that effect. CGS-26303 induced ECE-1 mRNA expression and ECE-1 promoter activity. CGS-35066, a selective ECE-1 inhibitor, mimicked the effects of CGS-26303, suggesting that the effect was specific to ECE-1 inhibition. Big ET-1 accumulated in the cells and in the supernatants after CGS-26303 treatment. Neither exogenously added ET-1 nor the blockade of their receptors with bosentan modified ECE-1 protein. When big ET-1 was added to cells, significant increases in ECE-1 protein content and ECE-1 promoter activity were found. Bosentan did not block those effects. CGS-26303 did not modify prepro-ET-1 expression. CGS-26303 and big ET-1 induced the same effects in human endothelial cells, at lower doses.
CONCLUSIONS
These results suggest that the accumulation of big ET-1 is responsible for the effects of CGS-26303 on ECE-1 and they did not depend on NEP blockade. Changes in ECE-1 protein after the administration of CGS-26303 could lead to a decreased response in long-term treatments.
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