title: Shear stress-induced ATP-mediated endothelial constitutive nitric oxide synthase expression in human lymphatic endothelial cells.
abstract: To clarify the roles of lymphatic endothelial cells (LEC) in the regulation of endothelial constitutive nitric oxide synthase (ecNOS) expression, we examined the effects of shear stress on ecNOS immunohistochemical staining and mRNA and protein expression in human LEC as well as on ATP release from these cells. Shear stress at 0.5 or 1.0 dyn/cm(2) increased ecNOS immunohistochemical staining and ecNOS mRNA and protein expression in cultured LEC. The same strength of shear stress produced a significant release of ATP from the LEC. Exogenous ATP ranging in concentration from 10(-9) to 10(-6) M produced a significant increase in ecNOS immunohistochemical expression in a dose-dependent manner. The increase in ecNOS expression mediated by 10(-6)M ATP was significantly reduced by 10(-5) M suramin. Suramin (10(-5) M) caused a significant reduction in the shear stress-mediated increases in ecNOS immunohistochemical staining and mRNA expression. The shear stress-mediated increases in ecNOS expression were significantly reduced by 3 mM tetraethylammonium, 10(-4) M apamin, 10(-9) M iberiotoxin, 10(-5) M 2-aminoethoxydephenyl borate, or 10(-5)M xestospongin C, but not 10(-5) M glybenclamide or 10(-5) M nifedipine. The shear stress-mediated increases in ecNOS expression were significantly potentiated by pinacidil or NS1619 in a dose-dependent manner. The immunohistochemical expression of small- (SK(Ca)) and big-conductance (BK(Ca)) Ca(2+)-activated K(+) channels was confirmed on the surfaces of human LEC. These findings suggest that shear stress produces a significant release of ATP from LEC, which activates the purinergic P2X/2Y receptor, thereby facilitating ecNOS mRNA and protein expression through inositol 1,4,5-trisphosphate-mediated release of intracellular Ca(2+) ions and the activation of Ca(2+)-activated K(+) channels in LEC.
authors.affiliation: Dept. of Physiology, School of Medicine, Shinshu University, Matsumoto, 390-8621, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kawai
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Maki
authors.initials: M
authors.lastname: Kaidoh
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohhashi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D015153:Blotting, Western; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004729:Endothelium, Lymphatic / Q000187:drug effects / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects / Q000378:metabolism; D058914:Purinergic Antagonists; D012333:RNA, Messenger / Q000378:metabolism; D011983:Receptors, Purinergic / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D002121:Calcium Channel Blockers; D053496:Inositol 1,4,5-Trisphosphate Receptors; D026902:Potassium Channel Blockers; D024681:Potassium Channels, Calcium-Activated; D058914:Purinergic Antagonists; D012333:RNA, Messenger; D011983:Receptors, Purinergic; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D011188:Potassium