title: Shear stress regulates inflammatory and thrombogenic gene transcripts in cultured human endothelial progenitor cells.
abstract: Shear stress has an established effect on mature endothelial cells, but less is known about how shear stress regulates endothelial progenitor cells (EPCs). In vitro expanded EPCs isolated from adult human blood represent a novel tool in regenerative vessel therapy. However, in vitro culturing may generate cells with unfavourable properties. The aim of the present study was therefore to assess whether shear stress may influence the inflammatory and thrombotic phenotype of in vitro expanded EPCs. In late outgrowth EPCs, 6 hours of shear stress (6.0 dynes/cm2) significantly reduced the mRNA levels of IL-8, COX2, and tissue factor (TF) compared to static controls. This was associated with a reduced TF activity. In contrast, mRNA expression of NOS3 was significantly increased following 6 and 24 hours of shear stress. In accordance with this, NOS3 protein expression was increased following 24 hours of shear stress. Overall stimulation with the proinflammatory mediator, TNFalpha, for the final 2 hours increased the mRNA expression of IL-6, IL-8, MCP-1, ICAM1, and TF. However exposure to 6 hours of shear stress significantly suppressed the inductory potential of TNFalpha to increase the mRNA levels of IL-6, IL-8, COX2, and TF. Additionally, TNFalpha increased TF activity approximately 10 times, an effect that was also significantly reduced by exposure to 6 and 24 hours of shear stress. The effect of shear on the gene levels of TF and NOS3 were not blocked by the NOS inhibitor L-NAME. These observations suggest that EPCs are capable of functionally responding to shear stress.
authors.affiliation: Cardiovascular Research Group, Department of Medical Biology, University of Tromsø, Tromsø, Norway.
authors.forename: Trine
authors.initials: T
authors.lastname: Lund
authors.forename: Stig E
authors.initials: SE
authors.lastname: Hermansen
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Andreasen
authors.forename: Jan Ole
authors.initials: JO
authors.lastname: Olsen
authors.forename: Bjarne
authors.initials: B
authors.lastname: Østerud
authors.forename: Truls
authors.initials: T
authors.lastname: Myrmel
authors.forename: Kirsti
authors.initials: K
authors.lastname: Ytrehus
mesh_terms: D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000235:genetics; D042783:Endothelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000235:genetics* / Q000276:immunology; D018836:Inflammation Mediators / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D016209:Interleukin-8 / Q000235:genetics; D040542:Mechanotransduction, Cellular / Q000235:genetics*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013314:Stress, Mechanical; D013925:Thromboplastin / Q000235:genetics; D013927:Thrombosis / Q000097:blood / Q000235:genetics*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C111835:CCL2 protein, human; C508606:CXCL8 protein, human; D018932:Chemokine CCL2; D004791:Enzyme Inhibitors; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D013925:Thromboplastin; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D019331:NG-Nitroarginine Methyl Ester