Endothelin converting enzyme activity in primary rat astrocytes is modulated by endothelin B receptors

• Verfasst von: Ehrenreich, Hannelore [VerfasserIn]
• Verfasst von: Löffler, Bernd-Michael [VerfasserIn]
• Verfasst von: Hasselblatt, Martin [VerfasserIn]
• Verfasst von: Langen, Hanno [VerfasserIn]
• Verfasst von: Oldenburg, Jan [VerfasserIn]
• Verfasst von: Subkowski, Thomas [VerfasserIn]
• Verfasst von: Schilling, Lothar [VerfasserIn]
• Verfasst von: Sirén, Anna-Leena [VerfasserIn]
• Titel: Endothelin converting enzyme activity in primary rat astrocytes is modulated by endothelin B receptors
• Verf.angabe: Hannelore Ehrenreich, Bernd-Michael Löffler, Martin Hasselblatt, Hanno Langen, Jan Oldenburg, Thomas Subkowski, Lothar Schilling, and Anna-Leena Sirén
• Jahr: 1999
• Umfang: 7 S.
• Fussnoten: Available online 25 May 2002 ; Gesehen am 24.03.2022
• Titel Quelle: Enthalten in: Biochemical and biophysical research communications
• Ort Quelle: [Amsterdam] : Elsevier B.V., 1959
• Jahr Quelle: 1999
• Band/Heft Quelle: 261(1999), 1, Seite 149-155
• ISSN Quelle: 1090-2104
• DOI: doi:10.1006/bbrc.1999.0924
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1796582964

Abstract

Astrocytes express endothelin-1 (ET-1), ET-3, and their receptors, ETA and ETB. We report here that activated astrocytes in vivo also express endothelin converting enzyme-1 (ECE-1). Higher basal ET-1 concentrations in astrocyte media from ETB-deficient (sl/sl) versus wildtype (+/+) rats suggested that altered ECE activity may be related to the absence of ETB receptors. Quantification of ECE activity in membranes from sl/sl astrocytes yielded a 50% higher conversion compared to +/+ astrocytes, with indistinguishable ECE-1 mRNA and protein levels. Kinetic analysis of ECE activity revealed similar Vmax values in sl/sl and +/+ astrocytes. Enzyme activity was competitively inhibited by phosphoramidon with Ki values of 0.6 and 0.3 μM, respectively. The Km value of ECE was 0.5 μM in +/+ and 0.2 μM in sl/sl astrocytes. Two-dimensional focussing of astrocytic ECE-1 uncovered heterogeneity of charge and molecular weight. ECE-1 from sl/sl revealed a glycosylation pattern different from +/+ astrocytes. In conclusion, the ETB receptor may, via ECE-1 glycosylation, exert a negative feedback on ECE activity in the astrocytic endothelin system.