Shear Stress–Dependent Regulation of the Human β-Tubulin Folding Cofactor D Gene

• Published in: Circulation research 2000-12, Vol.87 (12), p.1188-1194
• Main Authors: Schubert, Andreas, Cattaruzza, Marco, Hecker, Markus, Darmer, Dorothea, Holtz, Juergen, Morawietz, Henning
• Format: Article
• Language: English
• Subjects: Arteries - physiology; Biological and medical sciences; Blood vessels and receptors; Cells, Cultured; Cloning, Molecular; Down-Regulation; Endothelium, Vascular - drug effects; Endothelium, Vascular - physiology; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Humans; Microtubule-Associated Proteins - genetics; NG-Nitroarginine Methyl Ester - pharmacology; Nitric Oxide - metabolism; RNA, Messenger - biosynthesis; Transcription, Genetic; Vertebrates: cardiovascular system
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/01.RES.87.12.1188

ABSTRACT—The flowing blood generates shear stress at the endothelial cell surface. The endothelial cells modify their phenotype by alterations in gene expression in response to different levels of fluid shear stress. To identify genes involved in this process, human umbilical vein endothelial cells were exposed to laminar shear stress (venous or arterial levels) in a cone-and-plate apparatus for 24 hours. Using the method of RNA arbitrarily primed polymerase chain reaction, we cloned a polymerase chain reaction fragment representing an mRNA species downregulated by arterial compared with venous shear stress (shear stress downregulated gene-1, SSD-1). According to Northern blot analysis, corresponding SSD-1 cDNA clones revealed a similar, time-dependent downregulation after 24 hours of arterial shear stress compared with venous shear stress or static controls. Three SSD-1 mRNA species of 2.8, 4.1, and 4.6 kb were expressed in a tissue-specific manner. The encoded amino acid sequence of the human endothelial SSD-1 isoform (4.1-kb mRNA species) revealed 80.4% identity and 90.9% homology to the bovine β-tubulin folding cofactor D (tfcD) gene. Downregulation of tfcD mRNA expression by shear stress was defined at the level of transcription by nuclear run-on assays. The tfcD protein was downregulated by arterial shear stress. The shear stress–dependent downregulation of tfcD mRNA and protein was attenuated by the NO synthase inhibitor Nω-nitro-l-arginine methyl ester. Furthermore, the NO donor DETA-NO downregulated tfcD mRNA. Because tfcD was shown to be a microtubule-destabilizing protein, our data suggest a shear stress–dependent regulation of the microtubular dynamics in human endothelial cells.