Shear stress differentially regulates PGHS-1 and PGHS-2 protein levels in human endothelial cells

The secretion of prostacyclin (PGI2) by endothelial cells is regulated by shear stress. Prostaglandin H synthase (PGHS) is considered to be a key limiting enzyme in the synthesis of PGI2 from arachidonic acid. Endothelial cells were cultured in the presence of 4, 15, or 25 dyn/cm2 shear stress using...

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Veröffentlicht in:Annals of biomedical engineering 2000-07, Vol.28 (7), p.824-833
Hauptverfasser: McCormick, S M, Whitson, P A, Wu, K K, McIntire, L V
Format: Artikel
Sprache:eng
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Zusammenfassung:The secretion of prostacyclin (PGI2) by endothelial cells is regulated by shear stress. Prostaglandin H synthase (PGHS) is considered to be a key limiting enzyme in the synthesis of PGI2 from arachidonic acid. Endothelial cells were cultured in the presence of 4, 15, or 25 dyn/cm2 shear stress using a parallel plate flow chamber to assess the effect of shear stress on both PGHS isoforms, PGHS-1 and PGHS-2. In cells exposed to 4, 15, or 25 dyn/cm2 shear stress PGHS-1 and PGHS-2 protein levels initially decreased. The decrease was followed by a sustained increase for PGHS-1 but only a transient increase for PGHS-2. The duration of the PGHS-2 increase depended on the magnitude of the shear stress. The effect of altering shear stress levels on PGHS protein levels in cells preconditioned to either 4, 15, or 25 dyn/cm2 shear stress for 48 h was also studied. Changing shear stress levels effected PGHS-2 but not PGHS-1. Increases in shear stress levels from 4 to 15 or 25 dyn/cm2 caused a decrease in PGHS-2. In contrast, decreases in shear stress levels from 15 or 25 to 4 dyn/cm2 caused PGHS-2 to increase. There was a continual decrease in PGHS-2 when the shear stress was changed from 15 to 25 or 25 to 15 dyn/cm2. In summary, the regulation of PGHS-2 by shear stress is dependent upon the magnitude of the shear stress, whereas the regulation of PGHS-1 protein levels seems to be independent of the shear stress magnitude. The regulation of PGHS-1 and PGHS-2 protein levels by shear stress indicates that these proteins play an important role in the maintenance of cardiovascular homeostasis as regulators of PGI2 production.
ISSN:0090-6964
1573-9686
DOI:10.1114/1.1289472