title: Shear stress reduces protease activated receptor-1 expression in human endothelial cells.
abstract: Shear stress has been shown to regulate several genes involved in the thrombotic and proliferative functions of endothelial cells. Thrombin receptor (protease-activated receptor-1: PAR-1) increases at sites of vascular injury, which suggests an important role for PAR-1 in vascular diseases. However, the effect of shear stress on PAR-1 expression has not been previously studied. This work investigates effects of shear stress on PAR-1 gene expression in both human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (HMECs). Cells were exposed to different shear stresses using a parallel plate flow system. Northern blot and flow cytometry analysis showed that shear stress down-regulated PAR-1 messenger RNA (mRNA) and protein levels in both HUVECs and HMECs but with different thresholds. Furthermore, shear-reduced PAR-1 mRNA was due to a decrease of transcription rate, not increased mRNA degradation. Postshear stress release of endothelin-1 in response to thrombin was reduced in HUVECs and HMECs. Moreover, inhibitors of potential signaling pathways applied during shear stress indicated mediation of the shear-decreased PAR-1 expression by protein kinases. In conclusion, shear stress exposure reduces PAR-1 gene expression in HMECs and HUVECs through a mechanism dependent in part on protein kinases, leading to altered endothelial cell functional responses to thrombin.
authors: Institute of Biosciences and Bioengineering, Rice University, Houston, TX, USA.
authors: K T
authors: KT
authors: Nguyen
authors: S G
authors: SG
authors: Eskin
authors: C
authors: C
authors: Patterson
authors: M S
authors: MS
authors: Runge
authors: L V
authors: LV
authors: McIntire
mesh_terms: D001698:Biomedical Engineering; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D015536:Down-Regulation; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D011494:Protein Kinases / Q000378:metabolism; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin / Q000235:genetics* / Q000378:metabolism*; D013314:Stress, Mechanical; D013917:Thrombin / Q000494:pharmacology
chemical_list: D017077:Culture Media, Conditioned; D019332:Endothelin-1; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; D011494:Protein Kinases; D013917:Thrombin