To see the other types of publications on this topic, follow the link: Fibronectins Integrins Muscle.
Journal articles on the topic 'Fibronectins Integrins Muscle'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Fibronectins Integrins Muscle.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Balasubramanian, Lavanya, Abu Ahmed, Chun-Min Lo, James S. K. Sham, and Kay-Pong Yip. "Integrin-mediated mechanotransduction in renal vascular smooth muscle cells: activation of calcium sparks." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, no. 4 (October 2007): R1586—R1594. http://dx.doi.org/10.1152/ajpregu.00025.2007.
Full textAbstract:
Integrins are transmembrane heterodimeric proteins that link extracellular matrix (ECM) to cytoskeleton and have been shown to function as mechanotransducers in nonmuscle cells. Synthetic integrin-binding peptide triggers Ca2+ mobilization and contraction in vascular smooth muscle cells (VSMCs) of rat afferent arteriole, indicating that interactions between the ECM and integrins modulate vascular tone. To examine whether integrins transduce extracellular mechanical stress into intracellular Ca2+ signaling events in VSMCs, unidirectional mechanical force was applied to freshly isolated renal VSMCs through paramagnetic beads coated with fibronectin (natural ligand of α5β1-integrin in VSMCs). Pulling of fibronectin-coated beads with an electromagnet triggered Ca2+ sparks, followed by global Ca2+ mobilization. Paramagnetic beads coated with low-density lipoprotein, whose receptors are not linked to cytoskeleton, were minimally effective in triggering Ca2+ sparks and global Ca2+ mobilization. Preincubation with ryanodine, cytochalasin-D, or colchicine substantially reduced the occurrence of Ca2+ sparks triggered by fibronectin-coated beads. Binding of VSMCs with antibodies specific to the extracellular domains of α5- and β1-integrins triggered Ca2+ sparks simulating the effects of fibronectin-coated beads. Preincubation of microperfused afferent arterioles with ryanodine or integrin-specific binding peptide inhibited pressure-induced myogenic constriction. In conclusion, integrins transduce mechanical force into intracellular Ca2+ signaling events in renal VSMCs. Integrin-mediated mechanotransduction is probably involved in myogenic response of afferent arterioles.
2
Bunni, Marlene A., Inga I. Kramarenko, Linda Walker, John R. Raymond, and Maria N. Garnovskaya. "Role of integrins in angiotensin II-induced proliferation of vascular smooth muscle cells." American Journal of Physiology-Cell Physiology 300, no. 3 (March 2011): C647—C656. http://dx.doi.org/10.1152/ajpcell.00179.2010.
Full textAbstract:
Angiotensin II (AII) binds to G protein-coupled receptor AT1 and stimulates extracellular signal-regulated kinase (ERK), leading to vascular smooth muscle cells (VSMC) proliferation. Proliferation of mammalian cells is tightly regulated by adhesion to the extracellular matrix, which occurs via integrins. To study cross-talk between G protein-coupled receptor- and integrin-induced signaling, we hypothesized that integrins are involved in AII-induced proliferation of VSMC. Using Oligo GEArray and quantitative RT-PCR, we established that messages for α1-, α5-, αV-, and β1-integrins are predominant in VSMC. VSMC were cultured on plastic dishes or on plates coated with either extracellular matrix or poly-d-lysine (which promotes electrostatic cell attachment independent of integrins). AII significantly induced proliferation in VSMC grown on collagen I or fibronectin, and this effect was blocked by the ERK inhibitor PD-98059, suggesting that AII-induced proliferation requires ERK activity. VSMC grown on collagen I or on fibronectin demonstrated approximately three- and approximately sixfold increases in ERK phosphorylation after stimulation with 100 nM AII, respectively, whereas VSMC grown on poly-d-lysine demonstrated no significant ERK activation, supporting the importance of integrin-mediated adhesion. AII-induced ERK activation was reduced by >65% by synthetic peptides containing an RGD (arginine-glycine-aspartic acid) sequence that inhibit α5β1-integrin, and by ∼60% by the KTS (lysine-threonine-serine)-containing peptides specific for integrin-α1β1. Furthermore, neutralizing antibody against β1-integrin and silencing of α1, α5, and β1 expression by transfecting VSMC with short interfering RNAs resulted in decreased AII-induced ERK activation. This work demonstrates roles for specific integrins (most likely α5β1 and α1β1) in AII-induced proliferation of VSMC.
3
Anderson, M. J., Z. Q. Shi, and S. L. Zackson. "Proteolytic disruption of laminin-integrin complexes on muscle cells during synapse formation." Molecular and Cellular Biology 16, no. 9 (September 1996): 4972–84. http://dx.doi.org/10.1128/mcb.16.9.4972.
Full textAbstract:
To explore whether a neural modulation of muscle integrins' extracellular ligand interactions contributes to synapse induction, we compared the distributions of beta1-integrins and basal lamina proteins on Xenopus myotomal myocytes developing in culture. beta1-Integrins formed numerous organized aggregates scattered over the entire muscle surface, with particularly dense accumulations at specialized sites resembling myotendinous and neuromuscular junctions. Integrin aggregates on muscle cells differed from those on surrounding fibroblasts and epithelial cells, both in their lack of response to cross-linking by multivalent ligands and in their consistent association with the cells' own extracellular matrices. Muscle integrin clusters were usually associated with congruent basal lamina accumulations containing laminin and a heparan sulfate proteoglycan (HSPG), sometimes including fibronectin and vitronectin acquired from the surrounding medium. Immediately prior to synaptic differentiation, any existing laminin and HSPG accumulations along the path of cell contact were eliminated, disrupting otherwise stable laminin-integrin complexes. This apparently proteolytic modulation of integrins' extracellular ligand interactions was soon followed by the accumulation of new congruent accumulations of laminin and HSPG in the developing synaptic basal lamina. Combining these results with earlier findings, we consider the possibility that postsynaptic differentiation is induced, at least in part, by the proteolytic disruption of integrin-ligand complexes at sites of nerve-muscle contact.
4
Wei, Ying, Xiuwei Yang, Qiumei Liu, John A. Wilkins, and Harold A. Chapman. "A Role for Caveolin and the Urokinase Receptor in Integrin-mediated Adhesion and Signaling." Journal of Cell Biology 144, no. 6 (March 22, 1999): 1285–94. http://dx.doi.org/10.1083/jcb.144.6.1285.
Full textAbstract:
The assembly of signaling molecules surrounding the integrin family of adhesion receptors remains poorly understood. Recently, the membrane protein caveolin was found in complexes with β1 integrins. Caveolin binds cholesterol and several signaling molecules potentially linked to integrin function, e.g., Src family kinases, although caveolin has not been directly implicated in integrin-dependent adhesion. Here we report that depletion of caveolin by antisense methodology in kidney 293 cells disrupts the association of Src kinases with β1 integrins resulting in loss of focal adhesion sites, ligand-induced focal adhesion kinase (FAK) phosphorylation, and adhesion. The nonintegrin urokinase receptor (uPAR) associates with and stabilizes β1 integrin/caveolin complexes. Depletion of caveolin in uPAR-expressing 293 cells also disrupts uPAR/integrin complexes and uPAR-dependent adhesion. Further, β1 integrin/caveolin complexes could be disassociated by uPAR-binding peptides in both uPAR-transfected 293 cells and human vascular smooth muscle cells. Disruption of complexes by peptides in intact smooth muscle cells blocks the association of Src family kinases with β1 integrins and markedly impairs their migration on fibronectin. We conclude that ligand-induced signaling necessary for normal β1 integrin function requires caveolin and is regulated by uPAR. Caveolin and uPAR may operate within adhesion sites to organize kinase-rich lipid domains in proximity to integrins, promoting efficient signal transduction.
5
Thibault, Gaétan, Marie-Josée Lacombe, Lynn M. Schnapp, Alexandre Lacasse, Fatiha Bouzeghrane, and Geneviève Lapalme. "Upregulation of α8β1-integrin in cardiac fibroblast by angiotensin II and transforming growth factor-β1." American Journal of Physiology-Cell Physiology 281, no. 5 (November 1, 2001): C1457—C1467. http://dx.doi.org/10.1152/ajpcell.2001.281.5.c1457.
Full textAbstract:
Using a novel pharmacological tool with125I-echistatin to detect integrins on the cell, we have observed that cardiac fibroblasts harbor five different RGD-binding integrins: α8β1, α3β1, α5β1, αvβ1, and αvβ3. Stimulation of cardiac fibroblasts by angiotensin II (ANG II) or transforming growth factor-β1 (TGF-β1) resulted in an increase of protein and heightening by 50% of the receptor density of α8β1-integrin. The effect of ANG II was blocked by an AT1, but not an AT2, receptor antagonist, or by an anti-TGF-β1 antibody. ANG II and TGF-β1 increased fibronectin secretion, smooth muscle α-actin synthesis, and formation of actin stress fibers and enhanced attachment of fibroblasts to a fibronectin matrix. The α8- and β1-subunits were colocalized by immunocytochemistry with vinculin or β3-integrin at focal adhesion sites. These results indicate that α8β1-integrin is an abundant integrin on rat cardiac fibroblasts. Its positive modulation by ANG II and TGF-β1 in a myofibroblast-like phenotype suggests the involvement of α8β1-integrin in extracellular matrix protein deposition and cardiac fibroblast adhesion.
6
Medhora, Meetha M. "Retinoic acid upregulates β1-integrin in vascular smooth muscle cells and alters adhesion to fibronectin." American Journal of Physiology-Heart and Circulatory Physiology 279, no. 1 (July 1, 2000): H382—H387. http://dx.doi.org/10.1152/ajpheart.2000.279.1.h382.
Full textAbstract:
Retinoic acid has an established physiological role in differentiation, development, and cellular growth. This study investigated the action of all- trans retinoic acid (ATRA) on vascular integrins, cell-surface receptors that control growth and remodeling of blood vessels. The β1-integrin subunit mRNA and protein was induced after treatment with ATRA in two different rat vascular smooth muscle cell lines. To relate this result to the in vivo state, the aortas from adult rats fed with therapeutic doses of ATRA were examined for β1-integrin protein. A significant upregulation of the integrin subunit was observed in vivo. To assess if this increase contributed to physiological changes in cellular function, cells treated with ATRA were tested for alterations in adhesion to extracellular matrix proteins. The cells exposed to the retinoid were seen to adhere more strongly to fibronectin, via the β1-integrin. These results showed that modulation of vascular integrins by ATRA in adult rats contributes to functional changes that can cause remodeling of blood vessels.
7
Lomas, Amanda C., Kieran T. Mellody, Lyle J. Freeman, Daniel V. Bax, C. Adrian Shuttleworth, and Cay M. Kielty. "Fibulin-5 binds human smooth-muscle cells through α5β1 and α4β1 integrins, but does not support receptor activation." Biochemical Journal 405, no. 3 (July 13, 2007): 417–28. http://dx.doi.org/10.1042/bj20070400.
Full textAbstract:
Fibulin-5, an extracellular matrix glycoprotein expressed in elastin-rich tissues, regulates vascular cell behaviour and elastic fibre deposition. Recombinant full-length human fibulin-5 supported primary human aortic SMC (smooth-muscle cell) attachment through α5β1 and α4β1 integrins. Cells on fibulin-5 spread poorly and displayed prominent membrane ruffles but no stress fibres or focal adhesions, unlike cells on fibronectin that also binds these integrins. Cell migration and proliferation were significantly lower on fibulin-5 than on fibronectin. Treatment of cells on fibulin-5 with a β1 integrin-activating antibody induced stress fibres, increased attachment, migration and proliferation, and stimulated signalling of epidermal growth factor receptor and platelet-derived growth factor receptors α and β. Fibulin-5 also modulated fibronectin-mediated cell spreading and morphology. We have thus identified the β1 integrins on primary SMCs that fibulin-5 interacts with, and have shown that failure of fibulin-5 to activate these receptors limits cell spreading, migration and proliferation.
8
Balasubramanian, Lavanya, Chun-Min Lo, James S. K. Sham, and Kay-Pong Yip. "Remanent cell traction force in renal vascular smooth muscle cells induced by integrin-mediated mechanotransduction." American Journal of Physiology-Cell Physiology 304, no. 4 (February 15, 2013): C382—C391. http://dx.doi.org/10.1152/ajpcell.00234.2012.
Full textAbstract:
It was previously demonstrated in isolated renal vascular smooth muscle cells (VSMCs) that integrin-mediated mechanotransduction triggers intracellular Ca2+ mobilization, which is the hallmark of myogenic response in VSMCs. To test directly whether integrin-mediated mechanotransduction results in the myogenic response-like behavior in renal VSMCs, cell traction force microscopy was used to monitor cell traction force when the cells were pulled with fibronectin-coated or low density lipoprotein (LDL)-coated paramagnetic beads. LDL-coated beads were used as a control for nonintegrin-mediated mechanotransduction. Pulling with LDL-coated beads increased the cell traction force by 61 ± 12% (9 cells), which returned to the prepull level after the pulling process was terminated. Pulling with noncoated beads had a minimal increase in the cell traction force (12 ± 9%, 8 cells). Pulling with fibronectin-coated beads increased the cell traction force by 56 ± 20% (7 cells). However, the cell traction force was still elevated by 23 ± 14% after the pulling process was terminated. This behavior is analogous to the changes of vascular resistance in pressure-induced myogenic response, in which vascular resistance remains elevated after myogenic constriction. Fibronectin is a native ligand for α5β1-integrins in VSMCs. Similar remanent cell traction force was found when cells were pulled with beads coated with β1-integrin antibody (Ha2/5). Activation of β1-integrin with soluble antibody also triggered variations of cell traction force and Ca2+ mobilization, which were abolished by the Src inhibitor. In conclusion, mechanical force transduced by α5β1-integrins triggered a myogenic response-like behavior in isolated renal VSMCs.
9
White, Lindsay R., Jason B. Blanchette, Li Ren, Ali Awn, Kiril Trpkov, and Daniel A. Muruve. "The characterization of α5-integrin expression on tubular epithelium during renal injury." American Journal of Physiology-Renal Physiology 292, no. 2 (February 2007): F567—F576. http://dx.doi.org/10.1152/ajprenal.00212.2006.
Full textAbstract:
The hallmark of progressive chronic kidney disease is the deposition of extracellular matrix proteins and tubulointerstitial fibrosis. Integrins mediate cell-extracellular matrix interaction and may play a role tubular epithelial injury. Murine primary tubular epithelial cells (TECs) express α5-integrin, a fibroblast marker and the natural receptor for fibronectin. Microscopy localized α5-integrin on E-cadherin-positive cells, confirming epithelial expression. The expression of α5-integrin increased in TECs grown on fibronectin and occurred in parallel with an upregulation of α-smooth muscle actin (αSMA), a marker of epithelial-mesenchymal transition (EMT). Exposure of TECs to transforming growth factor (TGF)-β also increased TEC α5-integrin expression in association with αSMA and EMT. Knock-down of α5-integrin expression with short interfering RNA attenuated the TGF-β induction of αSMA but did not alter morphologic EMT. Rather, α5-integrin was necessary for epithelial cell migration on fibronectin but not type IV collagen during cell spreading and epithelial wound healing in vitro. Immunohistochemistry revealed basolateral tubular epithelial α5-integrin expression in mouse kidneys after unilateral ureteric obstruction but not in contralateral control kidneys. In patient biopsies of nondiabetic kidney disease, α5-integrin expression was increased significantly in the renal interstitium. Focal basolateral staining was also detected in injured, but not in normal, tubular epithelium. In summary, these data show that TECs are induced to express α5-integrin during EMT and tubular epithelial injury in vitro and in vivo. These results increase our understanding of the biology of integrins during EMT and tubular injury in chronic kidney disease.
10
Wu, Xin, Jon E. Mogford, Steven H. Platts, George E. Davis, Gerald A. Meininger, and Michael J. Davis. "Modulation of Calcium Current in Arteriolar Smooth Muscle by αvβ3 and α5β1 Integrin Ligands." Journal of Cell Biology 143, no. 1 (October 5, 1998): 241–52. http://dx.doi.org/10.1083/jcb.143.1.241.
Full textAbstract:
Vasoactive effects of soluble matrix proteins and integrin-binding peptides on arterioles are mediated by αvβ3 and α5β1 integrins. To examine the underlying mechanisms, we measured L-type Ca2+ channel current in arteriolar smooth muscle cells in response to integrin ligands. Whole-cell, inward Ba2+ currents were inhibited after application of soluble cyclic RGD peptide, vitronectin (VN), fibronectin (FN), either of two anti–β3 integrin antibodies, or monovalent β3 antibody. With VN or β3 antibody coated onto microbeads and presented as an insoluble ligand, current was also inhibited. In contrast, beads coated with FN or α5 antibody produced significant enhancement of current after bead attachment. Soluble α5 antibody had no effect on current but blocked the increase in current evoked by FN-coated beads and enhanced current when applied in combination with an appropriate IgG. The data suggest that αvβ3 and α5β1 integrins are differentially linked through intracellular signaling pathways to the L-type Ca2+ channel and thereby alter control of Ca2+ influx in vascular smooth muscle. This would account for the vasoactive effects of integrin ligands on arterioles and provide a potential mechanism for wound recognition during tissue injury.
11
Zhang, Lin, Hongyu Yan, Yifan Tai, Yueming Xue, Yongzhen Wei, Kai Wang, Qiang Zhao, Shufang Wang, Deling Kong, and Adam C. Midgley. "Design and Evaluation of a Polypeptide that Mimics the Integrin Binding Site for EDA Fibronectin to Block Profibrotic Cell Activity." International Journal of Molecular Sciences 22, no. 4 (February 4, 2021): 1575. http://dx.doi.org/10.3390/ijms22041575.
Full textAbstract:
Fibrosis is characterized by excessive production of disorganized collagen- and fibronectin-rich extracellular matrices (ECMs) and is driven by the persistence of myofibroblasts within tissues. A key protein contributing to myofibroblast differentiation is extra domain A fibronectin (EDA-FN). We sought to target and interfere with interactions between EDA-FN and its integrin receptors to effectively inhibit profibrotic activity and myofibroblast formation. Molecular docking was used to assist in the design of a blocking polypeptide (antifibrotic 38-amino-acid polypeptide, AF38Pep) for specific inhibition of EDA-FN associations with the fibroblast-expressed integrins α4β1 and α4β7. Blocking peptides were designed and evaluated in silico before synthesis, confirmation of binding specificity, and evaluation in vitro. We identified the high-affinity EDA-FN C-C′ loop binding cleft within integrins α4β1 and α4β7. The polypeptide with the highest predicted binding affinity, AF38Pep, was synthesized and could achieve specific binding to myofibroblast fibronectin-rich ECM and EDA-FN C-C′ loop peptides. AF38Pep demonstrated potent myofibroblast inhibitory activity at 10 µg/mL and was not cytotoxic. Treatment with AF38Pep prevented integrin α4β1-mediated focal adhesion kinase (FAK) activation and early signaling through extracellular-signal-regulated kinases 1 and 2 (ERK1/2), attenuated the expression of pro-matrix metalloproteinase 9 (MMP9) and pro-MMP2, and inhibited collagen synthesis and deposition. Immunocytochemistry staining revealed an inhibition of α-smooth muscle actin (α-SMA) incorporation into actin stress fibers and attenuated cell contraction. Increases in the expression of mRNA associated with fibrosis and downstream from integrin signaling were inhibited by treatment with AF38Pep. Our study suggested that AF38Pep could successfully interfere with EDA-FN C-C′ loop-specific integrin interactions and could act as an effective inhibitor of fibroblast of myofibroblast differentiation.
12
Belkin, Alexey M., S. Francesco Retta, Olga Y. Pletjushkina, Fiorella Balzac, Lorenzo Silengo, Reinhard Fassler, Victor E. Koteliansky, Keith Burridge, and Guido Tarone. "Muscle β1D Integrin Reinforces the Cytoskeleton–Matrix Link: Modulation of Integrin Adhesive Function by Alternative Splicing." Journal of Cell Biology 139, no. 6 (December 15, 1997): 1583–95. http://dx.doi.org/10.1083/jcb.139.6.1583.
Full textAbstract:
Expression of muscle-specific β1D integrin with an alternatively spliced cytoplasmic domain in CHO and GD25, β1 integrin-minus cells leads to their phenotypic conversion. β1D-transfected nonmuscle cells display rounded morphology, lack of pseudopodial activity, retarded spreading, reduced migration, and significantly enhanced contractility compared with their β1A-expressing counterparts. The transfected β1D is targeted to focal adhesions and efficiently displaces the endogenous β1A and αvβ3 integrins from the sites of cell–matrix contact. This displacement is observed on several types of extracellular matrix substrata and leads to elevated stability of focal adhesions in β1D transfectants. Whereas a significant part of cellular β1A integrin is extractable in digitonin, the majority of the transfected β1D is digitonin-insoluble and is strongly associated with the detergent-insoluble cytoskeleton. Increased interaction of β1D integrin with the actin cytoskeleton is consistent with and might be mediated by its enhanced binding to talin. In contrast, β1A interacts more strongly with α-actinin, than β1D. Inside-out driven activation of the β1D ectodomain increases ligand binding and fibronectin matrix assembly by β1D transfectants. Phenotypic effects of β1D integrin expression in nonmuscle cells are due to its enhanced interactions with both cytoskeletal and extracellular ligands. They parallel the transitions that muscle cells undergo during differentiation. Modulation of β1 integrin adhesive function by alternative splicing serves as a physiological mechanism reinforcing the cytoskeleton– matrix link in muscle cells. This reflects the major role for β1D integrin in muscle, where extremely stable association is required for contraction.
13
Garcı́a, Andrés J., Marı́a D. Vega, and David Boettiger. "Modulation of Cell Proliferation and Differentiation through Substrate-dependent Changes in Fibronectin Conformation." Molecular Biology of the Cell 10, no. 3 (March 1999): 785–98. http://dx.doi.org/10.1091/mbc.10.3.785.
Full textAbstract:
Integrin-mediated cell adhesion to extracellular matrices provides signals essential for cell cycle progression and differentiation. We demonstrate that substrate-dependent changes in the conformation of adsorbed fibronectin (Fn) modulated integrin binding and controlled switching between proliferation and differentiation. Adsorption of Fn onto bacterial polystyrene (B), tissue culture polystyrene (T), and collagen (C) resulted in differences in Fn conformation as indicated by antibody binding. Using a biochemical method to quantify bound integrins in cultured cells, we found that differences in Fn conformation altered the quantity of bound α5 and β1integrin subunits but not αv or β3. C2C12 myoblasts grown on these Fn-coated substrates proliferated to different levels (B > T > C). Immunostaining for muscle-specific myosin revealed minimal differentiation on B, significant levels on T, and extensive differentiation on C. Differentiation required binding to the RGD cell binding site in Fn and was blocked by antibodies specific for this site. Switching between proliferation and differentiation was controlled by the levels of α5β1 integrin bound to Fn, and differentiation was inhibited by anti-α5, but not anti-αv, antibodies, suggesting distinct integrin-mediated signaling pathways. Control of cell proliferation and differentiation through conformational changes in extracellular matrix proteins represents a versatile mechanism to elicit specific cellular responses for biological and biotechnological applications.
14
Belkin, V. M., A. M. Belkin, and V. E. Koteliansky. "Human smooth muscle VLA-1 integrin: purification, substrate specificity, localization in aorta, and expression during development." Journal of Cell Biology 111, no. 5 (November 1, 1990): 2159–70. http://dx.doi.org/10.1083/jcb.111.5.2159.
Full textAbstract:
A membrane glycoprotein complex was isolated and purified from human smooth muscle by detergent solubilization and affinity chromatography on collagen-Sepharose. The complex was identified as VLA-1 integrin and consisted of two subunits of 195 and 130 kD in SDS-PAGE. Liposomes containing the VLA-1 integrin adhered to surfaces coated with type I, II, III, and IV collagens, Clq subcomponent of the first component of the complement, and laminin. The liposomes specifically adhered to these proteins in a Ca2+, Mg2(+)-dependent manner, but did not bind to gelatin, fibronectin, and thrombospondin substrates. The expression of VLA-1 integrin in different human tissues and cell types, and during aorta smooth muscle development was studied by SDS-PAGE, and subsequent quantitative immunoblotting was performed with antibodies recognizing alpha 1 and beta 1 subunits of the VLA-1 integrin. A high level of VLA-1 integrin expression was an exceptional feature of smooth muscles. Fibroblasts, endothelial cells, keratinocytes, striated muscles, and platelets contained trace amounts of VLA-1 integrin. In the 10-wk-old human fetal aorta, VLA-1 integrin was found only in smooth muscle cells whereas mesenchymal cells, surrounding aortic smooth muscle cells, were VLA-1 integrin negative. By the 24th wk of gestation, the amount of VLA-1 integrin was significantly reduced in the aortic media (4.3-fold for alpha 1 subunit and 2.5-fold for beta 1 subunit) compared with that in the 10-wk-old aortic smooth muscle cells. After birth, the expression of VLA-1 integrin increased and in the 1.5-yr-old child aorta the VLA-1 integrin level was almost the same as in adult aortic media. Smooth muscle cells from intimal thickening of adult aorta express five times less alpha 1 subunit of VLA integrin that smooth muscle cells from adult aortic media. In primary culture of aortic smooth muscle cells, the content of the VLA-1 integrin was dramatically reduced and subcultured cells did not contain VLA-1 integrin at all.
15
Sun, Zhe, Luis A. Martinez-Lemus, Andreea Trache, Jerome P. Trzeciakowski, George E. Davis, Ulrich Pohl, and Gerald A. Meininger. "Mechanical properties of the interaction between fibronectin and α5β1-integrin on vascular smooth muscle cells studied using atomic force microscopy." American Journal of Physiology-Heart and Circulatory Physiology 289, no. 6 (December 2005): H2526—H2535. http://dx.doi.org/10.1152/ajpheart.00658.2004.
Full textAbstract:
The mechanical properties of integrin-extracellular matrix (ECM) interactions are important for the mechanotransduction of vascular smooth muscle cells (VSMC), a process that is associated with focal adhesions, and can be of particular significance in cardiovascular disease. In this study, we characterized the unbinding force and binding activity of the initial fibronectin (FN)-α5β1 interaction on the surface of VSMC using atomic force microscopy (AFM). It is postulated that these initial binding events are important to the subsequent focal adhesion assembly. FN-VSMC adhesions were selectively blocked by antibodies against α5- and β1-integrins as well as RGD-containing peptides but not by antibodies against α4- and β3-integrins, indicating that FN primarily bound to α5β1. A characteristic unbinding force of 39 ± 8 pN was observed and interpreted to represent the FN-α5β1 single-bond strength. The ability of FN to adhere to VSMC (binding probability) was significantly reduced by integrin antagonists, serum starvation, and platelet-derived growth factor (PDGF)-BB, whereas lysophosphatidic acid (LPA) increased FN binding. However, no significant change in the resolved unbinding force was observed. After engagement, the force required to dislodge the FN-coated bead from VSMC increased with increasing of contact time, suggesting a time-dependent increase in number of adhesions and/or altered binding affinity. LPA enhanced this process, whereas PDGF reduced it, suggesting that these factors also affect the multimolecular process of focal contact assembly. Thus AFM is a powerful tool for the characterization of the mechanical properties of integrin-ECM interactions and their regulation. Our results indicate that the functional activity of α5β1 and focal contact assembly can be rapidly regulated.
16
Sun, Zhe, Luis A. Martinez-Lemus, Michael A. Hill, and Gerald A. Meininger. "Extracellular matrix-specific focal adhesions in vascular smooth muscle produce mechanically active adhesion sites." American Journal of Physiology-Cell Physiology 295, no. 1 (July 2008): C268—C278. http://dx.doi.org/10.1152/ajpcell.00516.2007.
Full textAbstract:
Integrin-mediated mechanotransduction in vascular smooth muscle cells (VSMCs) plays an important role in the physiological control of tissue blood flow and vascular resistance. To test whether force applied to specific extracellular matrix (ECM)-integrin interactions could induce myogenic-like mechanical activity at focal adhesion sites, we used atomic force microscopy (AFM) to apply controlled forces to specific ECM adhesion sites on arteriolar VSMCs. The tip of AFM probes were fused with a borosilicate bead (2∼5 μm) coated with fibronectin (FN), collagen type I (CNI), laminin (LN), or vitronectin (VN). ECM-coated beads induced clustering of α5- and β3-integrins and actin filaments at sites of bead-cell contact indicative of focal adhesion formation. Step increases of an upward ( z-axis) pulling force (800∼1,600 pN) applied to the bead-cell contact site for FN-specific focal adhesions induced a myogenic-like, force-generating response from the VSMC, resulting in a counteracting downward pull by the cell. This micromechanical event was blocked by cytochalasin D but was enhanced by jasplakinolide. Function-blocking antibodies to α5β1- and αvβ3-integrins also blocked the micromechanical cell event in a concentration-dependent manner. Similar pulling experiments with CNI, VN, or LN failed to induce myogenic-like micromechanical events. Collectively, these results demonstrate that mechanical force applied to integrin-FN adhesion sites induces an actin-dependent, myogenic-like, micromechanical event. Focal adhesions formed by different ECM proteins exhibit different mechanical characteristics, and FN appears of particular relevance in its ability to strongly attach to VSMCs and to induce myogenic-like, force-generating reactions from sites of focal adhesion in response to externally applied forces.
17
Choi, Yoon-Ju, Hyun Ho Kim, Jeong-gyun Kim, Hye-Jin Kim, Minkyung Kang, Mi-Sook Lee, Jihye Ryu, et al. "TM4SF5 suppression disturbs integrin α5-related signalling and muscle development in zebrafish." Biochemical Journal 462, no. 1 (July 24, 2014): 89–101. http://dx.doi.org/10.1042/bj20140177.
Full textAbstract:
TM4SF5 suppression in zebrafish causes abnormal trunk morphology with aberrant translocation and organization of muscle cells, via altered fibronectin/integrin α5/FAK/vinculin/actin signalling. TM4SF5 controls muscle differentiation via alteration in integrin α5-related signalling.
18
Carmona, Guillaume, Emmanouil Chavakis, Ulrike Koehl, Andreas M. Zeiher, and Stefanie Dimmeler. "Activation of Epac stimulates integrin-dependent homing of progenitor cells." Blood 111, no. 5 (March 1, 2008): 2640–46. http://dx.doi.org/10.1182/blood-2007-04-086231.
Full textAbstract:
Cell therapy is a novel promising option for treatment of ischemic diseases. Administered endothelial progenitor cells (EPCs) are recruited to ischemic regions and improve neovascularization. However, the number of cells that home to ischemic tissues is restricted. The GTPase Rap1 plays an important role in the regulation of adhesion and chemotaxis. We investigated whether pharmacologic activation of Epac1, a nucleotide exchange protein for Rap1, which is directly activated by cAMP, can improve the adhesive and migratory capacity of distinct progenitor cell populations. Stimulation of Epac by a cAMP-analog increased Rap1 activity and stimulated the adhesion of human EPCs, CD34+ hematopoietic progenitor cells, and mesenchymal stem cells (MSCs). Specifically, short-term stimulation with a specific Epac activator increased the β2-integrin–dependent adhesion of EPCs to endothelial cell monolayers, and of EPC and CD34+ cells to ICAM-1. Furthermore, the Epac activator enhanced the β1-integrin–dependent adhesion of EPCs and MSCs to the matrix protein fibronectin. In addition, Epac1 activation induced the β1- and β2-integrin–dependent migration of EPCs on fibronectin and fibrinogen. Interestingly, activation of Epac rapidly increased lateral mobility of β1- and β2-integrins, thereby inducing integrin polarization, and stimulated β1-integrin affinity, whereas the β2-integrin affinity was not increased. Furthermore, prestimulation of EPCs with the Epac activator increased homing to ischemic muscles and neovascularization-promoting capacity of intravenously injected EPCs in the model of hind limb ischemia. These data demonstrate that activation of Epac1 increases integrin activity and integrin-dependent homing functions of progenitor cells and enhances their in vivo therapeutic potential. These results may provide a platform for the development of novel therapeutic approaches to improve progenitor cell homing.
19
Hazelgrove, Krystina B., Robert S. Flynn, Li-Ya Qiao, John R. Grider, and John F. Kuemmerle. "Endogenous IGF-I and αvβ3 integrin ligands regulate increased smooth muscle growth in TNBS-induced colitis." American Journal of Physiology-Gastrointestinal and Liver Physiology 296, no. 6 (June 2009): G1230—G1237. http://dx.doi.org/10.1152/ajpgi.90508.2008.
Full textAbstract:
Endogenous insulin-like growth factor-I (IGF-I) regulates intestinal smooth muscle growth by concomitantly stimulating proliferation and inhibiting apoptosis. IGF-I-stimulated growth is augmented by the αvβ3 integrin ligands vitronectin and fibronectin. IGF-I expression in smooth muscle is increased in both TNBS-induced colitis and Crohn's disease. We hypothesized that intestinal inflammation increased vitronectin and fibronectin expression by smooth muscle and, along with IGF-I upregulation, increased intestinal muscle growth. Intestinal smooth muscle cells were examined 7 days following the induction of TNBS-induced colitis. Although αvβ3 integrin expression was not altered by TNBS-induced colitis, vitronectin and fibronectin levels were increased by 80 ± 10% and 90 ± 15%, above control levels, respectively. Basal IGF-I receptor phosphorylation in inflamed muscle from TNBS-treated rats was increased by 86 ± 8% over vehicle-treated controls. Basal ERK1/2, p70S6 kinase, and GSK-3β phosphorylation in muscle cells of TNBS-treated rats were also increased by 140–180%. TNBS treatment increased basal muscle cell proliferation by 130 ± 15% and decreased apoptosis by 20 ± 2% compared with that in vehicle-treated controls. The changes in proliferation and apoptosis were reversed by an IGF-I receptor tyrosine kinase inhibitor or an αvβ3 integrin antagonist. The results suggest that smooth muscle hyperplasia in TNBS-induced colitis partly results from the upregulation of endogenous IGF-I and ligands of αvβ3 integrin that mediate increased smooth muscle cell proliferation and decreased apoptosis. This paper has identified one mechanism regulating smooth muscle hyperplasia, a feature of stricture formation that occurs in the chronically inflamed intestine of TNBS-induced colitis and potentially Crohn's disease.
20
De Strooper, B., B. Van der Schueren, M. Jaspers, M. Saison, M. Spaepen, F. Van Leuven, H. Van den Berghe, and J. J. Cassiman. "Distribution of the beta 1 subgroup of the integrins in human cells and tissues." Journal of Histochemistry & Cytochemistry 37, no. 3 (March 1989): 299–307. http://dx.doi.org/10.1177/37.3.2645360.
Full textAbstract:
We studied the distribution of the beta 1 integrin subfamily in human tissues and cells by light microscopy, electron microscopy, and immunoblotting, using monoclonal antibody DH12, previously shown to react with the beta 1 subunit of the human fibronectin receptor. Crossreaction with the other beta subunits of the integrin family, which have 45% and 47% primary amino acid sequence identity with the beta 1 subunit, was excluded, as MAb DH12 did not react with the beta 2 subunit in granulocytes and the beta 3 subunit in thrombocytes. Reactivity with the anti-beta 1 antibody was found in skin, lung, heart, striated and smooth muscle, blood cells, liver, kidney, intestine, spleen and placenta. Thus, cells of mesodermal, ectodermal, and entodermal origin express the beta 1 subunit. In skin fibroblasts cultured in vitro, beta 1 subunit was also detected intracellularly. The wide distribution of the beta 1 family, originally detected in activated T-lymphocytes after prolonged culture in vitro, contrast with the restricted distribution of the beta 2 integrins on leucocytes.
21
Taverna, Daniela, Marie-Helene Disatnik, Helen Rayburn, Roderick T. Bronson, Joy Yang, Thomas A. Rando, and Richard O. Hynes. "Dystrophic Muscle in Mice Chimeric for Expression of α5 Integrin." Journal of Cell Biology 143, no. 3 (November 2, 1998): 849–59. http://dx.doi.org/10.1083/jcb.143.3.849.
Full textAbstract:
α5-deficient mice die early in embryogenesis (Yang et al., 1993). To study the functions of α5 integrin later in mouse embryogenesis and during adult life we generated α5 −/−;+/+ chimeric mice. These animals contain α5-negative and positive cells randomly distributed. Analysis of the chimerism by glucose- 6-phosphate isomerase (GPI) assay revealed that α5 −/− cells contributed to all the tissues analyzed. High contributions were observed in the skeletal muscle. The perinatal survival of the mutant chimeras was lower than for the controls, however the subsequent life span of the survivors was only slightly reduced compared with controls (Taverna et al., 1998). Histological analysis of α5 −/−;+/+ mice from late embryogenesis to adult life revealed an alteration in the skeletal muscle structure resembling a typical muscle dystrophy. Giant fibers, increased numbers of nuclei per fiber with altered position and size, vacuoli and signs of muscle degeneration–regeneration were observed in head, thorax and limb muscles. Electron microscopy showed an increase in the number of mitochondria in some muscle fibers of the mutant mice. Increased apoptosis and immunoreactivity for tenascin-C were observed in mutant muscle fibers. All the alterations were already visible at late stages of embryogenesis. The number of altered muscle fibers varied in different animals and muscles and was often increased in high percentage chimeric animals. Differentiation of α5 −/− ES cells or myoblasts showed that in vitro differentiation into myotubes was achieved normally. However proper adhesion and survival of myoblasts on fibronectin was impaired. Our data suggest that a novel form of muscle dystrophy in mice is α5-integrin-dependent.
22
Disatnik, Marie-Hélène, Stéphane C. Boutet, Christine H. Lee, Daria Mochly-Rosen, and Thomas A. Rando. "Sequential activation of individual PKC isozymes in integrin-mediated muscle cell spreading: a role for MARCKS in an integrin signaling pathway." Journal of Cell Science 115, no. 10 (May 15, 2002): 2151–63. http://dx.doi.org/10.1242/jcs.115.10.2151.
Full textAbstract:
To understand how muscle cell spreading and survival are mediated by integrins, we studied the signaling events initiated by the attachment of muscle cells to fibronectin (FN). We have previously demonstrated that muscle cell spreading on FN is mediated by α5β1 integrin, is associated with rapid phosphorylation of focal adhesion kinase and is dependent on activation of protein kinase C (PKC). Here we investigated the role of individual PKC isozymes in these cellular processes. We show that α,δ and ϵPKC are expressed in muscle cells and are activated upon integrin engagement with different kinetics — ϵPKC was activated early, whereas α and δPKC were activated later. Using isozyme-specific inhibitors, we found that the activation of ϵPKC was necessary for cell attachment to FN. However, using isozyme-specific activators, we found that activation of each of three isozymes was sufficient to promote the spreading of α5-integrin-deficient cells on FN. To investigate further the mechanism by which integrin signaling and PKC activation mediate cell spreading, we studied the effects of these processes on MARCKS, a substrate of PKC and a protein known to regulate actin dynamics. We found that MARCKS was localized to focal adhesion sites soon after cell adhesion and that MARCKS translocated from the membrane to the cytosol during the process of cell spreading. This translocation correlated with different phases of PKC activation and with reorganization of the actin cytoskeleton. Using MARCKS-antisense cDNA, we show that α5-expressing cells in which MARCKS expression is inhibited fail to spread on FN, providing evidence for the crucial role of MARCKS in muscle cell spreading. Together, the data suggest a model in which early activation of ϵPKC is necessary for cell attachment; the later activation of α or δPKC may be necessary for the progression from attachment to spreading. The mechanism of PKC-mediated cell spreading may be via the phosphorylation of signaling proteins, such as MARCKS, that are involved in the reorganization of the actin cytoskeleton.
23
Neveux, Iva, Jinger Doe, Normand Leblanc, and Maria L. Valencik. "Influence of the extracellular matrix and integrins on volume-sensitive osmolyte anion channels in C2C12 myoblasts." American Journal of Physiology-Cell Physiology 298, no. 5 (May 2010): C1006—C1017. http://dx.doi.org/10.1152/ajpcell.00359.2009.
Full textAbstract:
The purpose of this study was to determine whether extracellular matrix (ECM) composition through integrin receptors modulated the volume-sensitive osmolyte anion channels (VSOACs) in skeletal muscle-derived C2C12 cells. Cl− currents were recorded in whole cell voltage-clamped cells grown on laminin (LM), fibronectin (FN), or in the absence of a defined ECM (NM). Basal membrane currents recorded in isotonic media (300 mosmol/kg) were larger in cells grown on FN (3.8-fold at +100 mV) or LM (8.8-fold at +100 mV) when compared with NM. VSOAC currents activated by cell exposure to hypotonic solution were larger in cells grown on LM (1.72-fold at +100 mV) or FN (1.75-fold at +100 mV) compared with NM. Additionally, the kinetics of VSOAC activation was ≈27% quicker on FN and LM. These currents were tamoxifen sensitive, displayed outward rectification, reversed at the equilibrium potential of Cl− and inactivated at potentials >+60 mV. Specific knockdown of β1-integrin by short hairpin RNA interference strongly inhibited the VSOAC Cl− currents in cells plated on FN. In conclusion, ECM composition and integrins profoundly influence the biophysical properties and mechanisms of onset of VSOACs.
24
Scaffidi, Amelia K., Yuben P. Moodley, Markus Weichselbaum, Philip J. Thompson, and Darryl A. Knight. "Regulation of human lung fibroblast phenotype and function by vitronectin and vitronectin integrins." Journal of Cell Science 114, no. 19 (October 1, 2001): 3507–16. http://dx.doi.org/10.1242/jcs.114.19.3507.
Full textAbstract:
Myofibroblasts, characterised by high expression of α-smooth muscle actin (α-SMA), are important and transient cells in normal wound healing but are found in increased number in various pathological conditions of the lung including asthma and pulmonary fibrosis. The mechanisms that regulate the myofibroblast phenotype are unknown but are likely to involve signals from the extracellular matrix transmitted via specific integrins. Vitronectin is a glycoprotein released during inflammation and has been shown to regulate the phenotype of vascular smooth muscle cells via αv and β1 integrins. In the current study we have examined whether vitronectin influences the phenotype and function of normal human lung fibroblasts (HFL-1). Incubation of HFL-1 cells with vitronectin induced a concentration-dependent reduction in α-SMA expression. By contrast, function-blocking monoclonal antibodies to the vitronectin integrins αv, β1, αvβ3 and αvβ5 induced the expression of α-SMA and its organization into stress fibers. Expression of α-SMA induced by all function-blocking monoclonal antibodies was abrogated by inhibition of protein kinase C and phosphatidylinositol-3 kinase, but the effects of inhibition of other signalling pathways was integrin dependent. Exposure to other extracellular matrix proteins such as fibronectin, collagen or their integrins did not influence expression of α-SMA. The expression and organization of α-SMA induced by exposure to function-blocking antibodies was translated into an augmented capacity of HFL-1 cells to contract fibroblast populated collagen gels. By contrast, contraction of collagen gels following incubation with vitronectin was not significantly different to control. This study has shown that vitronectin influences the phenotype and behaviour of HFL-1 cells by downregulating the expression of α-SMA and reducing their contractile ability. By contrast, occupancy of specific integrins by function-blocking antibodies upregulated the expression of α-SMA and induced the formation of functional stress fibers capable of contracting collagen gels. These results suggest that vitronectin modulates the fibroblast-myofibroblast phenotype, implying an important role in the remodelling process during lung development or response to injury.
25
de Jesus Perez, Vinicio A., Ziad Ali, Tero-Pekka Alastalo, Fumiaki Ikeno, Hirofumi Sawada, Ying-Ju Lai, Thomas Kleisli, et al. "BMP promotes motility and represses growth of smooth muscle cells by activation of tandem Wnt pathways." Journal of Cell Biology 192, no. 1 (January 10, 2011): 171–88. http://dx.doi.org/10.1083/jcb.201008060.
Full textAbstract:
We present a novel cell-signaling paradigm in which bone morphogenetic protein 2 (BMP-2) consecutively and interdependently activates the wingless (Wnt)–β-catenin (βC) and Wnt–planar cell polarity (PCP) signaling pathways to facilitate vascular smooth muscle motility while simultaneously suppressing growth. We show that BMP-2, in a phospho-Akt–dependent manner, induces βC transcriptional activity to produce fibronectin, which then activates integrin-linked kinase 1 (ILK-1) via α4-integrins. ILK-1 then induces the Wnt–PCP pathway by binding a proline-rich motif in disheveled (Dvl) and consequently activating RhoA-Rac1–mediated motility. Transfection of a Dvl mutant that binds βC without activating RhoA-Rac1 not only prevents BMP-2–mediated vascular smooth muscle cell motility but promotes proliferation in association with persistent βC activity. Interfering with the Dvl-dependent Wnt–PCP activation in a murine stented aortic graft injury model promotes extensive neointima formation, as shown by optical coherence tomography and histopathology. We speculate that, in response to injury, factors that subvert BMP-2–mediated tandem activation of Wnt–βC and Wnt–PCP pathways contribute to obliterative vascular disease in both the systemic and pulmonary circulations.
26
de Morrée, Antoine, Bàrbara Flix, Ivana Bagaric, Jun Wang, Marlinde van den Boogaard, Laure Grand Moursel, Rune R. Frants, et al. "Dysferlin Regulates Cell Adhesion in Human Monocytes." Journal of Biological Chemistry 288, no. 20 (April 4, 2013): 14147–57. http://dx.doi.org/10.1074/jbc.m112.448589.
Full textAbstract:
Dysferlin is mutated in a group of muscular dystrophies commonly referred to as dysferlinopathies. It is highly expressed in skeletal muscle, where it is important for sarcolemmal maintenance. Recent studies show that dysferlin is also expressed in monocytes. Moreover, muscle of dysferlinopathy patients is characterized by massive immune cell infiltrates, and dysferlin-negative monocytes were shown to be more aggressive and phagocytose more particles. This suggests that dysferlin deregulation in monocytes might contribute to disease progression, but the molecular mechanism is unclear. Here we show that dysferlin expression is increased with differentiation in human monocytes and the THP1 monocyte cell model. Freshly isolated monocytes of dysferlinopathy patients show deregulated expression of fibronectin and fibronectin-binding integrins, which is recapitulated by transient knockdown of dysferlin in THP1 cells. Dysferlin forms a protein complex with these integrins at the cell membrane, and its depletion impairs cell adhesion. Moreover, patient macrophages show altered adhesion and motility. These findings suggest that dysferlin is involved in regulating cellular interactions and provide new insight into dysferlin function in inflammatory cells.
27
Kuhara, T., S. Kagami, and Y. Kuroda. "Expression of beta 1-integrins on activated mesangial cells in human glomerulonephritis." Journal of the American Society of Nephrology 8, no. 11 (November 1997): 1679–87. http://dx.doi.org/10.1681/asn.v8111679.
Full textAbstract:
beta 1-integrins, a family of cell-surface receptors, mediate cell-matrix interactions that play a critical role in tissue development and tissue remodeling after injury. In this study, to clarify the importance of beta 1-integrins in human glomerulonephritis (GN), the relationship among the glomerular expression of beta 1-integrins, their ligand matrix components, alpha-smooth muscle actin (alpha-SM actin) as a marker of activated mesangial cells (MC), transforming growth factor-beta (TGF-beta), and glomerular cellularity in two normal kidneys, ten minimal change nephrotic syndrome, 23 immunoglobulin A (IgA) GN, 13 lupus GN, and four membranous GN kidneys were studied. Immunostaining was performed on frozen sections, using monoclonal anti-alpha-SM actin antibody and polyclonal antibodies against fibronectin, collagen type IV, laminin, each subunit of alpha 1 beta 1 (collagen/laminin receptor), alpha 5 beta 1 (fibronectin receptor) and TGF-beta. Quantitation of staining indicated that the glomerular expression of alpha 1 beta 1 and alpha 5 beta 1 integrins correlated with the mesangial amounts of their ligands, collagen type IV, laminin and fibronectin (P < 0.01), alpha-SM actin (P < 0.01), and TGF-beta (P < 0.01). In addition, a correlation was observed between an increased expression of alpha 1 beta 1 and alpha 5 beta 1 integrins and the degree of glomerular cell proliferation (P < 0.01). Double immunostaining showed that activated MC expressing alpha-SM actin strongly expressed alpha 1 beta 1 and alpha 5 beta 1 integrins, and these MC phenotypic alterations paralleled the level of glomerular TGF-beta staining (P < 0.01). In conclusion, enhanced expression of beta 1-integrins by activated MC may contribute to the pathological mesangial remodeling characterized by MC proliferation and matrix deposition in human GN. Increased glomerular TGF-beta appears to be involved in these MC phenotypic changes.
28
Chen, Yunliang, David J. Abraham, Xu Shi-wen, Jeremy D. Pearson, Carol M. Black, Karen M. Lyons, and Andrew Leask. "CCN2 (Connective Tissue Growth Factor) Promotes Fibroblast Adhesion to Fibronectin." Molecular Biology of the Cell 15, no. 12 (December 2004): 5635–46. http://dx.doi.org/10.1091/mbc.e04-06-0490.
Full textAbstract:
In vivo, CCN2 (connective tissue growth factor) promotes angiogenesis, osteogenesis, tissue repair, and fibrosis, through largely unknown mechanisms. In vitro, CCN2 promotes cell adhesion in a variety of systems via integrins and heparin sulfate proteoglycans (HSPGs). However, the physiological relevance of CCN2-mediated cell adhesion is unknown. Here, we find that HSPGs and the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cascade are required for adult human dermal fibroblasts to adhere to CCN2. Endogenous CCN2 directly binds fibronectin and the fibronectin receptors integrins α4 β1 and α5 and syndecan 4. Using Ccn2-/- mouse embryonic fibroblasts, we show that loss of endogenous CCN2 results in impaired spreading on fibronectin, delayed α-smooth muscle actin stress fiber formation, and reduced ERK and focal adhesion kinase phosphorylation. These results suggest that a physiological role of CCN2 is to potentiate the ability of fibroblasts to spread on fibronectin, which may be important in modulating fibroblast adhesion to the provisional matrix during tissue development and wound healing. These results are consistent with the notion that a principal function of CCN2 is to modulate receptor/ligand interactions in vivo.
29
Thorner, Paul, Laurence Heidet, Fernando Moreno Merlo, Vern Edwards, Corinne Antignac, and Marie-Claire Gubler. "Diffuse Leiomyomatosis of the Esophagus: Disorder of Cell-Matrix Interaction?" Pediatric and Developmental Pathology 1, no. 6 (November 1998): 543–49. http://dx.doi.org/10.1007/s100249900075.
Full textAbstract:
Diffuse leiomyomatosis (DL) is rare condition characterized by proliferation of smooth muscle in the upper gastrointestinal tract. Most cases are associated with X-linked Alport syndrome and have partial deletions in the genes encoding both the α5 and α6 chains of collagen type IV. We studied aspects of cell-matrix interaction of myocytes in an esophagogastrectomy specimen from a 12-year-old patient with DL. Myocytes had central areas of cytoplasmic rarefaction, which were actin positive and desmin poor, with the reverse pattern of staining at the cell periphery. Electron microscopy (EM) showed that the areas of rarefaction consisted of disorganized aggregates of filaments. The basement membranes ranged from thickened to thinned or absent. Immunohistochemical staining for the α1–α4 chains of collagen type IV, the α1, α2, β2, and γ1 chains of laminin, nidogen, type VI collagen, and fibronectin was normal. There was loss of the α5 and α6 chains of collagen type IV and the β1 chain of laminin. Normal staining for α1, α2, α3, α4, α6, α8, and β1 integrins was noted. Staining for α5 integrin varied from normal to reduced or negative in different cells. In DL, a primary abnormality of basement membrane may be associated with disorganization of the contractile apparatus and alterations of certain integrins. This may reflect a disturbance of cell-matrix interactions that play a role in cell differentiation and internal organization.
30
Clyman, R. I., J. Tannenbaum, Y. Q. Chen, D. Cooper, P. D. Yurchenco, R. H. Kramer, and N. S. Waleh. "Ductus arteriosus smooth muscle cell migration on collagen: dependence on laminin and its receptors." Journal of Cell Science 107, no. 4 (April 1, 1994): 1007–18. http://dx.doi.org/10.1242/jcs.107.4.1007.
Full textAbstract:
During permanent closure of the ductus arteriosus, smooth muscle cells migrate through the extracellular matrix (ECM) to form intimal mounds that occlude the vessel's lumen. Smooth muscle cells (SMC) migrate over surfaces coated with collagen in vitro. During the migration SMC also synthesize fibronectin (FN) and laminin (LN). Antibodies against FN and LN inhibit migration on collagen by 30% and 67%, respectively. Because of the apparent importance of LN in migration, we examined how SMC interact with LN and LN fragments (P1, E8, P1′, E1′, E3, E4, and G). Ductus SMC adhere to high concentrations of LN and two fragments of the molecule: P1 and E8. They use a unique set of integrin receptors to bind to LN (alpha 1 beta 1, alpha 6 beta 1 and alpha v beta 3), to P1 (alpha 1 beta 1, alpha v beta 3), and to E8 (alpha 6 beta 1, alpha v beta 3). The alpha v beta 3 integrin binds to the P1 fragment of LN in an RGD peptide-dependent manner, and to the E8 fragment in an RGD-independent manner; the RGD site on the P1 fragment probably is not available to the cell in intact LN. Antibodies against beta 1 integrins completely inhibit SMC adhesion to LN; antibodies against the alpha v beta 3 integrin do not block SMC adhesion to LN, but do prevent cell spreading. LN is also capable of interfering with SMC adhesion to other ECM components. The antiadhesive effect of LN is located in the E1′ domain. Both exogenous and endogenous LN increase SMC motility on collagen I. The locomotion-promoting activity of LN resides in the E1′ antiadhesive domain, and not in its adhesive (P1, E8) domains. LN causes a decrease in the number of focal contacts on collagen I. This might enable SMC to alter their mobility as they move through the extracellular matrix to occlude the ductus arteriosus lumen.
31
Negash, S., S. R. Narasimhan, W. Zhou, J. Liu, F. L. Wei, J. Tian, and J. Usha Raj. "Role of cGMP-dependent protein kinase in regulation of pulmonary vascular smooth muscle cell adhesion and migration: effect of hypoxia." American Journal of Physiology-Heart and Circulatory Physiology 297, no. 1 (July 2009): H304—H312. http://dx.doi.org/10.1152/ajpheart.00077.2008.
Full textAbstract:
Exposure to prolonged hypoxia can result in pulmonary vascular remodeling and pulmonary hypertension. Hypoxia induces pulmonary vascular smooth muscle cell (PVSMC) proliferation and vascular remodeling by affecting cell adhesion and migration and secretion of extracellular matrix proteins. We previously showed that acute hypoxia decreases cGMP-dependent protein kinase (PKG) activity in PVSMC and that PKG plays a role in maintaining the differentiated contractile phenotype in normoxia. In this study, we investigated the effect of hypoxia on PVSMC adhesion and migration and the role of PKG in these functions. Ovine fetal pulmonary artery SMC were incubated in normoxia (Po2 ∼100 Torr) or hypoxia (Po2 ∼30–40 Torr) or treated with the PKG inhibitor DT-3 for 24 h in normoxia. To further study the role of PKG in the modulation of adhesion and migration, PVSMC were transiently transfected with a full-length PKG1α [PKG-green fluorescent protein (GFP)] or a dominant-negative construct (G1αR-GFP). Cell adhesion to extracellular matrix proteins was determined, and integrin-mediated adhesion was assessed by α/β-integrin-mediated cell adhesion array. Exposure to hypoxia (24 h) and pharmacological inhibition of PKG1 by DT-3 significantly promoted adhesion mediated by α4-, β1-, and α5β1-integrins to fibronectin, laminin, and tenacin and also resulted in increased cell migration. Likewise, inhibition of PKG by expression of a dominant-negative PKG1α construct increased cell adhesion and migration, comparable to that induced by hypoxia. Dynamic actin reorganization associated with integrin-mediated cell adhesion is partly regulated by the actin-binding protein cofilin, the (Ser3) phosphorylation of which inhibits its actin-severing activity. We found that increased PKG expression and activity is associated with decreased cofilin (Ser3) phosphorylation, implying a role for PKG in the modulation of cofilin activity and actin dynamics. Together, these findings identify cGMP/PKG1 signaling as central to the functional differences between PVSMC exposed to normoxia versus hypoxia.
32
Gu, M., W. Wang, W. K. Song, D. N. Cooper, and S. J. Kaufman. "Selective modulation of the interaction of alpha 7 beta 1 integrin with fibronectin and laminin by L-14 lectin during skeletal muscle differentiation." Journal of Cell Science 107, no. 1 (January 1, 1994): 175–81. http://dx.doi.org/10.1242/jcs.107.1.175.
Full textAbstract:
The alpha 7 beta 1 integrin was originally identified and isolated from differentiating skeletal muscle and shown to be a laminin-binding protein (Song et al. (1992) J. Cell Biol. 117, 643–657). Expression of the alpha 7 gene and protein are developmentally regulated during skeletal muscle differentiation and have been used to identify cells at distinct stages of the myogenic lineage (George-Weinstein et al. (1993) Dev. Biol. 156, 209–229). The lactoside-binding protein L-14 exists as a dimer and has been localized on a variety of cells, in association with extracellular matrix. During myogenesis in vitro, L-14 is synthesized within replicating myoblasts but it is not secreted until these cells commence terminal differentiation and fusion into multinucleate fibers (Cooper and Barondes, J. Cell Biol. (1990) 110, 1681–1691). Addition of purified L-14 to myogenic cells plated on laminin inhibits myoblast spreading and fusion, suggesting that the L-14 lectin regulates muscle cell interactions with the extracellular matrix that are germane to myogenic development (Cooper et al. (1991) J. Cell Biol. 115, 1437–1448). We demonstrate here, using affinity chromatography and immunoblots, that alpha 7 beta 1 also binds to fibronectin and to the L-14 lectin. L-14 binds to both laminin and to the alpha 7 beta 1 integrin, and it can effectively inhibit the association of laminin and this integrin. Modulation of alpha 7 beta 1 interaction with its ligands by L-14 is selective: L-14 does not bind to fibronectin, nor does it interfere with the binding of fibronectin to alpha 7 beta 1.(ABSTRACT TRUNCATED AT 250 WORDS)
33
Wang, Xue-Qing, and William A. Frazier. "The Thrombospondin Receptor CD47 (IAP) Modulates and Associates with α2β1 Integrin in Vascular Smooth Muscle Cells." Molecular Biology of the Cell 9, no. 4 (April 1998): 865–74. http://dx.doi.org/10.1091/mbc.9.4.865.
Full textAbstract:
The carboxyl-terminal domain of thrombospondin-1 enhances the migration and proliferation of smooth muscle cells. Integrin-associated protein (IAP or CD47) is a receptor for the thrombospondin-1 carboxyl-terminal cell-binding domain and binds the agonist peptide 4N1K (kRFYVVMWKk) from this domain. 4N1K peptide stimulates chemotaxis of both human and rat aortic smooth muscle cells on gelatin-coated filters. The migration on gelatin is specifically blocked by monoclonal antibodies against IAP and a β1 integrin, rather than αvβ3 as found previously for 4N1K-stimulated chemotaxis of endothelial cells on gelatin. Both human and rat smooth muscle cells displayed a weak migratory response to soluble type I collagen; however, the presence of 4N1K peptide or intact thrombospondin-1 provoked a synergistic chemotactic response that was partially blocked by antibodies to α2 and β1 integrin subunits and to IAP. A combination of antiα2 and IAP monoclonal antibodies completely blocked chemotaxis. RGD peptide and antiαvβ3 mAb were without effect. 4N1K and thrombospondin-1 did not augment the chemotactic response of smooth muscle cells to fibronectin, vitronectin, or collagenase-digested type I collagen. Complex formation between α2β1 and IAP was detected by the coimmunoprecipitation of both α2 and β1 integrin subunits with IAP. These data suggest that IAP can associate with α2β1 integrin and modulate its function.
34
Dash, Biraja C., Kaiti Duan, Themis R. Kyriakides, and Henry C. Hsia. "Integrin β3 targeting biomaterial preferentially promotes secretion of bFGF and viability of iPSC-derived vascular smooth muscle cells." Biomaterials Science 9, no. 15 (2021): 5319–29. http://dx.doi.org/10.1039/d1bm00162k.
Full textAbstract:
Fibronectin functionalized collagen scaffold promotes the proangiogenic secretion and viability of hiPSC-VSMC via αvβ3 signaling. The current study also suggests a positive feedback loop between integrin β3, bFGF, and MMP-2 modulating hiPSC-VSMC.
35
Kuemmerle, John F. "Occupation of αvβ3-integrin by endogenous ligands modulates IGF-I receptor activation and proliferation of human intestinal smooth muscle." American Journal of Physiology-Gastrointestinal and Liver Physiology 290, no. 6 (June 2006): G1194—G1202. http://dx.doi.org/10.1152/ajpgi.00345.2005.
Full textAbstract:
We have previously shown that endogenous IGF-I regulates growth of human intestinal smooth muscle cells by stimulating proliferation and inhibiting apoptosis. In active Crohn's disease, expression of IGF-I and the αvβ3-integrin receptor ligands fibronectin and vitronectin is increased. The aim of the present study was to determine whether occupation of the αvβ3-receptor influences IGF-I receptor tyrosine kinase activation and function in human intestinal smooth muscle cells. In untreated cells, IGF-I elicited time-dependent tyrosine phosphorylation of its cognate receptor that was maximal within 2 min and sustained for 30 min. In the presence of the αvβ3-ligand fibronectin, IGF-I-stimulated IGF-I receptor activation was augmented. Conversely, in the presence of the αvβ3-specific disintegrin echistatin, IGF-I-stimulated IGF-I receptor tyrosine kinase phosphorylation was inhibited. IGF-I-stimulated IGF-I receptor activation was accompanied by recruitment of the adapter protein IRS-1, activation of Erk1/2, p70S6 kinase, and proliferation. These effects were augmented by fibronectin and attenuated by echistatin. IGF-I also elicited time-dependent recruitment of protein tyrosine phosphatase SHP-2 that coincided with dephosphorylation of the tyrosine phosphorylated IGF-I receptor tyrosine kinase. The αvβ3-disintegrin echistatin accelerated the rate of SHP-2 recruitment and deactivation of the IGF-I receptor tyrosine kinase. The results show that occupancy of the αvβ3-integrin receptor modulates IGF-I-induced IGF-I receptor activation and function in human intestinal muscle cells. We hypothesize that the concomitant increases in the expression of αvβ3-ligands and of IGF-I in active Crohn's disease may contribute to muscle hyperplasia and stricture formation by acting in concert to augment IGF-I-stimulated IGF-I receptor tyrosine kinase activity and IGF-I-mediated muscle cell growth.
36
Robinson, Paul A., Susan Brown, Meagan J. McGrath, Imogen D. Coghill, Rajendra Gurung, and Christina A. Mitchell. "Skeletal muscle LIM protein 1 regulates integrin-mediated myoblast adhesion, spreading, and migration." American Journal of Physiology-Cell Physiology 284, no. 3 (March 1, 2003): C681—C695. http://dx.doi.org/10.1152/ajpcell.00370.2002.
Full textAbstract:
The skeletal muscle LIM protein 1 (SLIM1) is highly expressed in skeletal and cardiac muscle, and its expression is downregulated significantly in dilated human cardiomyopathy. However, the function of SLIM1 is unknown. In this study, we investigated the intracellular localization of SLIM1. Endogenous and recombinant SLIM1 localized to the nucleus, stress fibers, and focal adhesions in skeletal myoblasts plated on fibronectin, collagen, or laminin. However, after inhibition of integrin signaling either by plating on poly-l-lysine or by soluble RGD peptide, SLIM1 localized diffusely in the cytosol, with decreased nuclear expression. Disruption of the actin cytoskeleton by cytochalasin D did not inhibit nuclear localization of SLIM1 in integrin-activated cells. Green fluorescent protein-tagged SLIM1 shuttled in the nucleus of untransfected NIH 3T3 cells, in a heterokaryon fusion assay. Overexpression of SLIM1 in Sol8 myoblasts inhibited cell adhesion and promoted cell spreading and migration. These studies show SLIM1 localizes in an integrin-dependent manner to the nucleus and focal adhesions where it functions downstream of integrin activation to promote cell spreading and migration.
37
Balzac, F., A. M. Belkin, V. E. Koteliansky, Y. V. Balabanov, F. Altruda, L. Silengo, and G. Tarone. "Expression and functional analysis of a cytoplasmic domain variant of the beta 1 integrin subunit." Journal of Cell Biology 121, no. 1 (April 1, 1993): 171–78. http://dx.doi.org/10.1083/jcb.121.1.171.
Full textAbstract:
We have previously described a variant form of the integrin beta 1 subunit (beta 1B)1 characterized by an altered sequence at the cytoplasmic domain. Using polyclonal antibodies to a synthetic peptide corresponding to the unique sequence of the beta 1B, we analyzed the expression of this molecule in human tissues and cultured cells. Western blot analysis showed that the beta 1B is expressed in skin and liver and, in lower amounts, in skeletal and cardiac muscles. The protein was not detectable in brain, kidney, and smooth muscle. In vitro cultured keratinocytes and hepatoma cells are positive, but fibroblasts, endothelial cells, and smooth muscle cells are negative. An astrocytoma cell line derived from immortalized fetal astrocytes was found to express beta 1B. In these cells beta 1B represent integral of 30% of the beta 1 and form heterodimers with alpha 1 and alpha 5 subunits. To investigate the functional properties of beta 1B, the full-length cDNA coding for this molecule was transfected into CHO cells. Stable transfectants were selected and the beta 1B was identified by a mAb that discriminate between the transfected human protein and the endogenous hamster beta 1A. Immunoprecipitation experiments indicated that the beta 1B was exported at the cell surface in association with the endogenous hamster alpha subunits. The alpha 5/beta 1B complex bound to a fibronectin-affinity matrix and was specifically released by RGD-containing peptides. Thus beta 1B and beta 1A are similar as far as the alpha/beta association and fibronectin binding are concerned. The two proteins differ, however, in their subcellular localization. Immunofluorescence studies indicated, in fact, that beta 1B, in contrast to beta 1A, does not localize in focal adhesions. The restricted tissue distribution and the distinct subcellular localization, suggest that beta 1B has unique functional properties.
38
Nguyen, Trang T. B., Jeremy P. T. Ward, and Stuart J. Hirst. "β1-Integrins Mediate Enhancement of Airway Smooth Muscle Proliferation by Collagen and Fibronectin." American Journal of Respiratory and Critical Care Medicine 171, no. 3 (February 2005): 217–23. http://dx.doi.org/10.1164/rccm.200408-1046oc.
Full text
39
Dhar, Srijita, Zhe Sun, Gerald A. Meininger, and Michael A. Hill. "Nonenzymatic glycation interferes with fibronectin-integrin interactions in vascular smooth muscle cells." Microcirculation 24, no. 3 (April 2017): e12347. http://dx.doi.org/10.1111/micc.12347.
Full text
40
Chamorro-Jorganes, Aranzazu, Laura Calleros, Mercedes Griera, Marta Saura, Alicia Luengo, D. Rodriguez-Puyol, and M. Rodriguez-Puyol. "Fibronectin upregulates cGMP-dependent protein kinase type Iβ through C/EBP transcription factor activation in contractile cells." American Journal of Physiology-Cell Physiology 300, no. 3 (March 2011): C683—C691. http://dx.doi.org/10.1152/ajpcell.00251.2010.
Full textAbstract:
The nitric oxide (NO)-soluble guanylate cyclase (sGC) pathway exerts most of its cellular actions through the activation of the cGMP-dependent protein kinase (PKG). Accumulation of extracellular matrix is one of the main structural changes in pathological conditions characterized by a decreased activity of this pathway, such as hypertension, diabetes, or aging, and it is a well-known fact that extracellular matrix proteins modulate cell phenotype through the interaction with membrane receptors such as integrins. The objectives of this study were 1) to evaluate whether extracellular matrix proteins, particularly fibronectin (FN), modulate PKG expression in contractile cells, 2) to analyze the mechanisms involved, and 3) to evaluate the functional consequences. FN increased type I PKG (PKG-I) protein content in human mesangial cells, an effect dependent on the interaction with β1-integrin. The FN upregulation of PKG-I protein content was due to increased mRNA expression, determined by augmented transcriptional activity of the PKG-I promoter region. Akt and the transcription factor CCAAT enhancer-binding protein (C/EBP) mediated the genesis of these changes. FN also increased PKG-I in another type of contractile cell, rat vascular smooth muscle cells (RVSMC). Tirofiban, a pharmacological analog of FN, increased PKG-I protein content in RVSMC and rat aortic walls and magnified the hypotensive effect of dibutyryl cGMP in conscious Wistar rats. The present results provide evidence of a mechanism able to increase PKG-I protein content in contractile cells. Elucidation of this novel mechanism provides a rationale for future pharmacotherapy in certain vascular diseases.
41
Dekkers, Bart G. J., Dedmer Schaafsma, S. Adriaan Nelemans, Johan Zaagsma, and Herman Meurs. "Extracellular matrix proteins differentially regulate airway smooth muscle phenotype and function." American Journal of Physiology-Lung Cellular and Molecular Physiology 292, no. 6 (June 2007): L1405—L1413. http://dx.doi.org/10.1152/ajplung.00331.2006.
Full textAbstract:
Changes in the ECM and increased airway smooth muscle (ASM) mass are major contributors to airway remodeling in asthma and chronic obstructive pulmonary disease. It has recently been demonstrated that ECM proteins may differentially affect proliferation and expression of phenotypic markers of cultured ASM cells. In the present study, we investigated the functional relevance of ECM proteins in the modulation of ASM contractility using bovine tracheal smooth muscle (BTSM) preparations. The results demonstrate that culturing of BSTM strips for 4 days in the presence of fibronectin or collagen I depressed maximal contraction (Emax) both for methacholine and KCl, which was associated with decreased contractile protein expression. By contrast, both fibronectin and collagen I increased proliferation of cultured BTSM cells. Similar effects were observed for PDGF. Moreover, PDGF augmented fibronectin- and collagen I-induced proliferation in an additive fashion, without an additional effect on contractility or contractile protein expression. The fibronectin-induced depression of contractility was blocked by the integrin antagonist Arg-Gly-Asp-Ser (RGDS) but not by its negative control Gly-Arg-Ala-Asp-Ser-Pro (GRADSP). Laminin, by itself, did not affect contractility or proliferation but reduced the effects of PDGF on these parameters. Strong relationships were found between the ECM-induced changes in Emax in BTSM strips and their proliferative responses in BSTM cells and for Emax and contractile protein expression. Our results indicate that ECM proteins differentially regulate both phenotype and function of intact ASM.
42
Chao, Jun-Tzu, Peichun Gui, Gerald W. Zamponi, George E. Davis, and Michael J. Davis. "Spatial association of the Cav1.2 calcium channel with α5β1-integrin." American Journal of Physiology-Cell Physiology 300, no. 3 (March 2011): C477—C489. http://dx.doi.org/10.1152/ajpcell.00171.2010.
Full textAbstract:
Engagement of α5β1-integrin by fibronectin (FN) acutely enhances Cav1.2 channel (CaL) current in rat arteriolar smooth muscle and human embryonic kidney cells (HEK293-T) expressing CaL. Using coimmunoprecipitation strategies, we show that coassociation of CaL with α5- or β1-integrin in HEK293-T cells is specific and depends on cell adhesion to FN. In rat arteriolar smooth muscle, coassociations between CaL and α5β1-integrin and between CaL and phosphorylated c-Src are also revealed and enhanced by FN treatment. Using site-directed mutagenesis of CaL heterologously expressed in HEK293-T cells, we identified two regions of CaL required for these interactions: 1) COOH-terminal residues Ser1901 and Tyr2122, known to be phosphorylated by protein kinase A (PKA) and c-Src, respectively; and 2) two proline-rich domains (PRDs) near the middle of the COOH terminus. Immunofluorescence confocal imaging revealed a moderate degree of wild-type CaL colocalization with β1-integrin on the plasma membrane. Collectively, our results strongly suggest that 1) upon ligation by FN, CaL associates with α5β1-integrin in a macromolecular complex including PKA, c-Src, and potentially other protein kinases; 2) phosphorylation of CaL at Y2122 and/or S1901 is required for association of CaL with α5β1-integrin; and 3) c-Src, via binding to PRDs that reside in the II–III linker region and/or the COOH terminus of CaL, mediates current potentiation following α5β1-integrin engagement. These findings provide new evidence for how interactions between α5β1-integrin and FN can modulate CaL entry and consequently alter the physiological function of multiple types of excitable cells.
43
Rabinovitch, Marlene. "EVE and beyond, retro and prospective insights." American Journal of Physiology-Lung Cellular and Molecular Physiology 277, no. 1 (July 1, 1999): L5—L12. http://dx.doi.org/10.1152/ajplung.1999.277.1.l5.
Full textAbstract:
Our work has focused on the discovery that an endogenous vascular elastase (EVE) plays a pivotal role in the vascular changes associated with the development and progression of pulmonary hypertension. Recent studies have identified serum factors that stimulate transcription of this enzyme and have elucidated a signal transduction process involving activation of the mitogen-activated protein kinase pathway and nuclear expression of the transcription factor AML1. Proteases release and activate growth factors that are bound to the extracellular matrix and also induce, in a β3-integrin-dependent manner, the transcription of the gene for the matrix glycoprotein tenascin. Tenascin alters smooth muscle cell shape and facilitates the proliferative response to growth factors by clustering and activating growth factor receptors. In addition, breakdown products of elastin, elastin peptides, can upregulate the production of fibronectin, a glycoprotein that is critical to smooth muscle cell migration. The mechanisms regulating enhanced fibronectin production have recently been successfully targeted to prevent the development of intimal lesions.
44
Yamaguchi, Youhei, Tatsuya Ishigaki, Koushi Sano, Kei-Ichi Miyamoto, Shinsuke Nomura, and Takashi Horiuchi. "Three-Dimensional Invasion of Epithelial–Mesenchymal Transition–Positive Human Peritoneal Mesothelial Cells into Collagen Gel is Promoted by the Concentration Gradient of Fibronectin." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 31, no. 4 (July 2011): 477–85. http://dx.doi.org/10.3747/pdi.2010.00166.
Full textAbstract:
BackgroundIn long-term peritoneal dialysis, myofibroblast-like cells found in the interstitium of the peritoneum are assumed to be a transformed type of mesothelial cell—epithelial-mesenchymal transition-positive [EMT(+)] human peritoneal mesothelial cells (HPMCs)—because they express a mesothelial marker, cytokeratin. However, no direct evidence about how these cells are able to invade from the mesothelium has yet been obtained.AimIn this study, we aimed to verify whether EMT(+) HPMCs would, in vitro, invade three-dimensionally along certain chemotactic factors.MethodsWe used reverse-transcriptase polymerase chain reaction to measure expression of Snail, E-cadherin, α5-integrin, and matrix metalloproteinase 2 (MMP2) messenger RNA (mRNA) in HPMCs exposed to 10 ng/mL transforming growth factor β1 (TGFβ1) and how that expression corresponds to cell motility, as represented by a video movie. We used the Transwell (12 μm pore diameter: Sigma-Aldrich, Tokyo, Japan) to construct a three-dimensional (3D) cell migration chamber. In the lower chamber, a concentration gradient of fibronectin (FN) or albumin(Alb) was formed in 0.1% type I collagen by diffusion ( C0= 22 nmol/L; concentration gradient: C / C0= 0.7). All cells beneath the membrane were counted 72 hours after 5x104EMT(+) HPMCs (HPMCs after a 48-hour exposure to 10 ng/mL TGFβ1) had been spread in the upper chamber.ResultsAfter 72 hours, the increased motility of HPMCs resulting from their exposure to 10 ng/mL TGFβ1 had returned to baseline, but they retained an elongated morphology. Expression of Snail and MMP2 mRNA reached maximum at 24 hours. Expression of E-cadherin declined, and expression of α5-integrin increased continuously. In the 3D invasion study, significantly enhanced invasion by EMT(+) but not EMT(-) HPMCs was clearly seen in the presence of a FN concentration gradient ( p < 0.01), although invasion by EMT(+) and EMT(-) HPMCs in the absence of a FN concentration gradient was not statistically significantly different. Compared with the EMT(+) control (no concentration gradient), invasion by EMT(+) HPMCs was 2.1 ± 0.5 times (p < 0.05) and 1.4 ± 0.4 times (p = nonsignificant) higher along the FN and Alb concentration gradients respectively. Increased invasion along the FN concentration gradient was significantly inhibited (p < 0.05) when the HPMCs were pre-incubated with 5 μg/mL RGDS (a blocker for α5-integrin to FN).ConclusionsWe conclude that EMT(+) HPMCs invade collagen gel along the FN concentration gradient because of specific binding to RGDS receptors, which bind integrins such as α5-integrin, upregulating invasion-related gene expression associated with synthesis of the cytoskeleton protein α smooth muscle actin.
45
Tomatis, Daniela, Frank Echtermayer, Stephan Schöber, Fiorella Balzac, Saverio Francesco Retta, Lorenzo Silengo, and Guido Tarone. "The Muscle-Specific Laminin Receptor α7β1 Integrin Negatively Regulates α5β1 Fibronectin Receptor Function." Experimental Cell Research 246, no. 2 (February 1999): 421–32. http://dx.doi.org/10.1006/excr.1998.4315.
Full text
46
Zhu, Yi, Li He, Jing Qu, and Yong Zhou. "Regulation of Vascular Smooth Muscle Cell Stiffness and Adhesion by [Ca2+]i: An Atomic Force Microscopy-Based Study." Microscopy and Microanalysis 24, no. 6 (December 2018): 708–12. http://dx.doi.org/10.1017/s1431927618015519.
Full textAbstract:
AbstractThe intracellular concentration of calcium ion ([Ca2+]i) is a critical regulator of cell signaling and contractility of vascular smooth muscle cells (VSMCs). In this study, we employed an atomic force microscopy (AFM) nanoindentation-based approach to investigate the role of [Ca2+]i in regulating the cortical elasticity of rat cremaster VSMCs and the ability of rat VSMCs to adhere to fibronectin (Fn) matrix. Elevation of [Ca2+]i by ionomycin treatment increased rat VSMC stiffness and cell adhesion to Fn-biofunctionalized AFM probes, whereas attenuation of [Ca2+]i by 1,2-Bis (2-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA-AM) treatment decreased the mechanical and matrix adhesive properties of VSMCs. Furthermore, we found that ionomycin/BAPTA-AM treatments altered expression of α5 integrin subunits and α smooth muscle actin in rat VSMCs. These data suggest that [Ca2+]i regulates VSMC elasticity and adhesion to the extracellular matrix by a potential mechanism involving changing dynamics of the integrin–actin cytoskeleton axis.
47
Wu, Xin, Sanjukta Chakraborty, Cristine L. Heaps, Michael J. Davis, Gerald A. Meininger, and Mariappan Muthuchamy. "Fibronectin increases the force production of mouse papillary muscles via α5β1 integrin." Journal of Molecular and Cellular Cardiology 50, no. 1 (January 2011): 203–13. http://dx.doi.org/10.1016/j.yjmcc.2010.10.003.
Full text
48
Lu, Katherine Kun, Shayn E. Armstrong, Roman Ginnan, and Harold A. Singer. "Adhesion-dependent activation of CaMKII and regulation of ERK activation in vascular smooth muscle." American Journal of Physiology-Cell Physiology 289, no. 5 (November 2005): C1343—C1350. http://dx.doi.org/10.1152/ajpcell.00064.2005.
Full textAbstract:
Cell adhesion-dependent activation of ERK1/2 has been linked functionally to focal adhesion dynamics. We previously reported that in adherent vascular smooth muscle (VSM) cells, CaMKII mediates ERK1/2 activation in response to Ca2+-mobilizing stimuli. In the present study, we tested whether CaMKII regulates ERK1/2 signaling in response to VSM cell adhesion. Using an antibody that specifically recognizes CaMKII autophosphorylated on Thr287, we determined that CaMKII is rapidly activated (within 1 min) after the adherence of cells on multiple ECM substrates. Activation of CaMKII on fibronectin was unaffected in cells overexpressing focal adhesion kinase (FAK)-related nonkinase (FRNK), an endogenous inhibitor of FAK. Furthermore, CaMKII was rapidly and robustly activated in VSM cells plated on poly-l-lysine. These results suggest that adhesion-dependent CaMKII activation is integrin independent. Adhesion-dependent FAK activation on fibronectin was not affected in cells treated with the selective CaMKII inhibitor KN-93 (30 μM) or in cells in which the expression of CaMKII with small interfering RNA (siRNA) was suppressed, although tyrosine phosphorylation of paxillin was inhibited in CaMKII-δ2-suppressed cells. Sustained ERK1/2 activation that was dependent on FAK activation (inhibited by FRNK) was also attenuated by CaMKII inhibition or siRNA-mediated gene silencing. Rapid ERK1/2 activation that preceded FAK and paxillin activation was detected upon VSM cell adhesion to poly-l-lysine, and this response was inhibited by CaMKII gene silencing. These results indicate that integrin-independent CaMKII activation is an early signal during VSM cell adhesion that positively modulates ERK1/2 signaling through FAK-dependent and FAK-independent mechanisms.
49
Glenn, Honor L., Zhaohui Wang, and Lawrence M. Schwartz. "Acheron, a Lupus antigen family member, regulates integrin expression, adhesion, and motility in differentiating myoblasts." American Journal of Physiology-Cell Physiology 298, no. 1 (January 2010): C46—C55. http://dx.doi.org/10.1152/ajpcell.00387.2009.
Full textAbstract:
Acheron (Achn) was originally identified as novel gene that is induced when insect muscles become committed to die at the end of metamorphosis. In separate studies, we have demonstrated that Achn acts upstream of MyoD and is required by mammalian myoblasts to either differentiate or undergo apoptosis following loss of growth factors. In the present study we examined the role of Achn in regulating integrin-extracellular matrix interactions that are required for myogenesis. Both control C2C12 myoblasts and those engineered to express ectopic Achn expressed the fibronectin receptor integrin α5β1 in the presence of growth factors and the laminin receptor α7β1 following growth factor withdrawal. Expression of the laminin receptor was blocked in cells expressing either Achn antisense or an Achn deletion mutant that blocks differentiation. Control cells and those expressing ectopic Achn undergo sequential and transient increases in both substrate adhesion and migration before cell fusion. Blockade of Achn expression reduced these effects on laminin but not on fibronectin. Taken together, these data suggest that Achn may influence differentiation in part via its control of cell adhesion dynamics.
50
Osses, Nelson, and Enrique Brandan. "ECM is required for skeletal muscle differentiation independently of muscle regulatory factor expression." American Journal of Physiology-Cell Physiology 282, no. 2 (February 1, 2002): C383—C394. http://dx.doi.org/10.1152/ajpcell.00322.2001.
Full textAbstract:
Transcription of specific skeletal muscle genes requires the expression of the muscle regulatory factor myogenin. To assess the role of the extracellular matrix (ECM) in skeletal muscle differentiation, the specific inhibitors of proteoglycan synthesis, sodium chlorate and β-d-xyloside, were used. Treatment of cultured skeletal muscle cells with each inhibitor substantially abolished the expression of creatine kinase and α-dystroglycan. This inhibition was totally reversed by the addition of exogenous ECM. Myoblast treatment with each inhibitor affected the deposition and assembly of the ECM constituents glypican, fibronectin, and laminin. These treatments did not affect MyoD, MEF2A, and myogenin expression and nuclear localization. Differentiated myoblast treatment with RGDS peptides completely inhibited myogenesis without affecting the expression or nuclear localization of myogenin. Integrin-mediated signaling of focal adhesion kinase was partially inhibited by chlorate and β-d-xyloside, an effect reversed by the addition of exogenous ECM gel. These results suggested that the expression of myogenin is not sufficient to successfully drive skeletal muscle formation and that ECM is required to complete the skeletal muscle differentiation process.