Mechanical force isan important stimulus for many vascular smooth muscle cell (VSMC) functions including the contractile process, proliferation, migration, and attachment. These functions define physiological properties of the vasculature like control of blood flow, capillary pressure and peripheral vascular resistance and play a role in pathophysiological processes. Integrins are important receptors for extracellular matrix (ECM) proteins that mediate both force transmission and signal transduction. Consequently, integrins have been hypothesized to be the mechanosensor in VSMC and play a central role in mechanotransduction and the myogenic response. Our knowledge, however, concerning how integrins sense and transduce physical forces into cellular signals and which integrins are involved is incomplete. Thus, important questions concern the nature and origin of integrin-mediated signaling in VSMC and the link between integrins and the myogenic response. Our cQntral hypothesis is that initiation of mechanically induced cell signaling in VSMC by integrins ((_s_l, _v_, cc4_1i)nvolves either integrin bond formation, bond stressing and/or bond dissociation between integrins and ECM proteins (fibronectin (FN) and vitronectin (VN)).
The specific aims of this proposal are: 1. To measure the receptor-ligand unbinding or dissociation force between VSMC _131, c_1_3o, r c?4_lintegrinswith the ECM proteins FN and VN. 2. To determine if integdn- ECM (FN and VN) bond formation, bond stressing or forced bond dissociation on the VSMC membrane result in changes of [Ca2*]i and further determine whether the [Ca2+]ichanges result in detectable alterations of cortical VSMC stiffness/elasticity. 3. To determine the role of focal adhesion proteins in regulation of VSMC calcium by the _, m,_3, or e_4_lintegdns. 4. To determine the effect of _1, _3, or o_integrin receptor antagonism on the pressure-dependent myogenic response and Ca 2*signaling of isolated arterioles. To accomplish these aims, cultured arteriole VSMC and isolated arterioles from rat skeletal muscle will be used. The binding forces between FN and VN and their integrin receptors, measurements cell cortical stiffness and measurements of VSMC [Ca2*]=will be performed using a unique hybrid Atomic Force Microscope (AFM)/Fluorescence Microscope System. Studies in the isolated arteriole will provide a means for integration of data from molecular scale to the intact tissue level. We predict that the innovative approaches used will provide new information for understanding the mechanism of VSMC mechano- sensation and -transduction.
|Sun, Zhe; Li, Zhaohui; Meininger, Gerald A (2012) Mechanotransduction through fibronectin-integrin focal adhesion in microvascular smooth muscle cells: is calcium essential? Am J Physiol Heart Circ Physiol 302:H1965-73|
|Qiu, Hongyu; Zhu, Yi; Sun, Zhe et al. (2010) Short communication: vascular smooth muscle cell stiffness as a mechanism for increased aortic stiffness with aging. Circ Res 107:615-9|
|Huang, Shaoxing; Sun, Zhe; Li, Zhaohui et al. (2010) Modulation of microvascular smooth muscle adhesion and mechanotransduction by integrin-linked kinase. Microcirculation 17:113-27|
|Sun, Zhe; Martinez-Lemus, Luis A; Hill, Michael A et al. (2008) Extracellular matrix-specific focal adhesions in vascular smooth muscle produce mechanically active adhesion sites. Am J Physiol Cell Physiol 295:C268-78|
|Chao, Jun-Tzu; Martinez-Lemus, Luis A; Kaufman, Stephen J et al. (2006) Modulation of alpha7-integrin-mediated adhesion and expression by platelet-derived growth factor in vascular smooth muscle cells. Am J Physiol Cell Physiol 290:C972-80|
|Sarin, Vandana; Gaffin, Robert D; Meininger, Gerald A et al. (2005) Arginine-glycine-aspartic acid (RGD)-containing peptides inhibit the force production of mouse papillary muscle bundles via alpha 5 beta 1 integrin. J Physiol 564:603-17|
|Martinez-Lemus, Luis A; Crow, Tracy; Davis, Michael J et al. (2005) alphavbeta3- and alpha5beta1-integrin blockade inhibits myogenic constriction of skeletal muscle resistance arterioles. Am J Physiol Heart Circ Physiol 289:H322-9|
|Neiger, Jessemy D; Crow, Tracy Y; Partridge, Charles R et al. (2005) Modulation of alpha4 integrin mRNA levels is coupled to deficits in vasomotor function in rat arterioles by allylamine. Life Sci 76:1895-905|
|Na, S; Sun, Z; Meininger, G A et al. (2004) On atomic force microscopy and the constitutive behavior of living cells. Biomech Model Mechanobiol 3:75-84|
|Chao, Jun-Tzu; Meininger, Gerald A; Patterson, Jan L et al. (2004) Regulation of alpha7-integrin expression in vascular smooth muscle by injury-induced atherosclerosis. Am J Physiol Heart Circ Physiol 287:H381-9|
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