title: Extracellular matrix fibronectin mediates an endothelial cell response to shear stress via the heparin-binding, matricryptic RWRPK sequence of FNIII1H.
abstract: Endothelial cells (EC) respond to mechanical forces such as shear stress in a variety of ways, one of which is cytoskeletal realignment in the direction of flow. Our earlier studies implicated the extracellular matrix protein fibronectin in mechanosensory signaling to ECs in intact arterioles, via a signaling pathway dependent on the heparin-binding region of the first type III repeat of fibrillar fibronectin (FNIII1H). Here we test the hypothesis that FNIII1H is required for EC stress fiber realignment under flow. Human umbilical vein ECs (HUVECs) exposed to defined flow conditions were used as a well-characterized model of this stress fiber alignment response. Our results directly implicate FNIII1H in realignment of stress fibers in HUVECs and, importantly, show that the matricryptic heparin-binding RWRPK sequence located in FNIII1 is required for the response. Furthermore, we show that flow-mediated stress fiber realignment in ECs adhered via α5β1-integrin-specific ligands does not occur in the absence of FHIII1H, whereas, in contrast, αvβ3-integrin-mediated stress fiber realignment under flow does not require FNIII1H. Our findings thus indicate that there are two separate mechanosignaling pathways mediating the alignment of stress fibers after exposure of ECs to flow, one dependent on αvβ3-integrins and one dependent on FNIII1H. This study strongly supports the conclusion that the RWRPK region of FNIII1H may have broad capability as a mechanosensory signaling site.
authors: Department of Biomedical Engineering, University of Rochester, Rochester, New York; and.
authors: William
authors: W
authors: Okech
authors: Department of Pharmacology and Physiology, University of Rochester, Rochester, New York.
authors: Keren M
authors: KM
authors: Abberton
authors: Department of Pharmacology and Physiology, University of Rochester, Rochester, New York.
authors: Julia M
authors: JM
authors: Kuebel
authors: Department of Biomedical Engineering, University of Rochester, Rochester, New York; and Department of Pharmacology and Physiology, University of Rochester, Rochester, New York.
authors: Denise C
authors: DC
authors: Hocking
authors: Department of Biomedical Engineering, University of Rochester, Rochester, New York; and Department of Pharmacology and Physiology, University of Rochester, Rochester, New York Ingrid_sarelius@urmc.rochester.edu.
authors: Ingrid H
authors: IH
authors: Sarelius
mesh_terms: D042783:Endothelial Cells / Q000378:metabolism* / Q000502:physiology; D005109:Extracellular Matrix / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism*; D006493:Heparin; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D008856:Microscopy, Fluorescence; D013314:Stress, Mechanical
chemical_list: D005353:Fibronectins; D039081:Integrin alpha5beta1; D039302:Integrin alphaVbeta3; D006493:Heparin
keywords: extracellular matrix signaling; fluid shear stress-dependent endothelial responses; mechanotransduction in endothelium