title: Fluid shear stress inhibits vascular inflammation by decreasing thioredoxin-interacting protein in endothelial cells.
abstract: Regions in the vasculature that are exposed to steady laminar blood flow are protected from atherosclerosis as compared with regions where flow is disturbed. We found that flow decreased TNF-mediated VCAM1 expression by inhibiting JNK and p38. JNK inhibition correlated with inhibition of apoptosis signal-regulating kinase 1 (ASK1), a JNK and p38 activator. Thioredoxin-interacting protein (TXNIP) is a stress-responsive protein that inhibits thioredoxin (TRX) activity. Since thioredoxin inhibits ASK1, we hypothesized that changes in TXNIP-TRX-ASK1 interactions mediate the antiinflammatory effects of flow. To explore this, we used perfused vessels and cultured ECs. Exposure of rabbit aortae or ECs to normal flow (12 dyn/cm2, 24 hours) was associated with decreased TXNIP expression and increased TRX activity compared with exposure to low flow (0.4 dyn/cm2). Normal flow inhibited TNF activation of JNK/p38 and VCAM1 expression. In cultured ECs, reduction of TXNIP expression by small interfering RNA increased TRX binding to ASK1 and inhibited TNF activation of JNK/p38 and VCAM1 expression. Conversely, overexpression of TXNIP stimulated JNK and p38. In aortae from TXNIP-deficient mice, TNF-induced VCAM1 expression was inhibited. The data suggest that TXNIP and TRX are key components of biomechanical signal transduction and establish them as potentially novel regulators of TNF signaling and inflammation in ECs.
authors.affiliation: Center for Cardiovascular Research, University of Rochester, Rochester, New York 14642, USA.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yamawaki
authors.forename: Shi
authors.initials: S
authors.lastname: Pan
authors.forename: Richard T
authors.initials: RT
authors.lastname: Lee
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Berk
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology* / Q000276:immunology* / Q000473:pathology; D001783:Blood Flow Velocity; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation; D066298:In Vitro Techniques; D007249:Inflammation / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D033081:Shear Strength; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical; D013879:Thioredoxins / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D013879:Thioredoxins; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases