scholarly journals Anchorage of VEGF to the extracellular matrix conveys differential signaling responses to endothelial cells

2010 ◽  
Vol 188 (4) ◽  
pp. 595-609 ◽  
Author(s):  
Tom T. Chen ◽  
Alfonso Luque ◽  
Sunyoung Lee ◽  
Sean M. Anderson ◽  
Tatiana Segura ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Molecular Mechanisms ◽  
Focal Adhesions ◽  
Extracellular Proteins ◽  
Β1 Integrin ◽  
Vascular Morphogenesis ◽  
Downstream Effectors ◽  
Differential Signaling ◽  
Matrix Bound

VEGF can be secreted in multiple isoforms with variable affinity for extracellular proteins and different abilities to induce vascular morphogenesis, but the molecular mechanisms behind these effects remain unclear. Here, we show molecular distinctions between signaling initiated from soluble versus matrix-bound VEGF, which mediates a sustained level of VEGFR2 internalization and clustering. Exposure of endothelial cells to matrix-bound VEGF elicits prolonged activation of VEGFR2 with differential phosphorylation of Y1214, and extended activation kinetics of p38. These events require association of VEGFR2 with β1 integrins. Matrix-bound VEGF also promotes reciprocal responses on β1 integrin by inducing its association with focal adhesions; a response that is absent upon exposure to soluble VEGF. Inactivation of β1 integrin blocks the prolonged phosphorylation of Y1214 and consequent activation of p38. Combined, these results indicate that when in the context of extracellular matrix, activation of VEGFR2 is distinct from that of soluble VEGF in terms of recruitment of receptor partners, phosphorylation kinetics, and activation of downstream effectors.

Abstract MP254: Decellularized Extracellular Matrix Hydrogel Lowers Fibrosis And Fibroblast Differentiation In Post-injury Mice Hearts Through Capg

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Xinming Wang ◽  
Samuel Senyo
Keyword(s):  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Smooth Muscle Actin ◽  
Growth Factor Receptor ◽  
Inhibitory Effect ◽  
Extracellular Proteins ◽  
Collagen Deposition ◽  
Post Injury ◽  
Capping Protein ◽  
Decellularized Extracellular Matrix

Hypothesis and objective: We hypothesize that transplantation of decellularized cardiac extracellular matrix (dECM) lowers fibrosis and fibroblast differentiation. In this study we investigated collagen deposition and fibroblast differentiation in post-MI hearts and heart explants of various stiffness after dECM hydrogel treatments. The objectives are 1) determining if dECM derived from fetal and adult porcine hearts reduces fibrosis in injured hearts; and 2) identifying specific signaling pathways that regulate fibroblasts differentiation induced by extracellular proteins. Methods: Porcine dECM was injected immediately after ligating coronary artery in P1 mice. Histology was conducted on day 7 post-myocardial infarction (MI). A mice ventricle explant model was used to investigate the molecular mechanisms. Results: We observed that fetal dECM treatment lowered fibrosis and fibroblast differentiation in post-MI hearts (Fig.1). Fibroblast differentiation as indicated by α-smooth muscle actin expression in vimentin or platelet derived growth factor receptor α positive cells showed an inhibitory effect of fetal dECM on fibroblast differentiation. Using a heart explant model of modulated microenvironment stiffness, we demonstrated that increasing tissue stiffness stimulates fibroblast differentiation and collagen deposition. Fetal dECM treatment, however, inhibited fibroblast differentiation induced by increasing microenvironment stiffness. Transcriptome analysis revealed that two cytoskeleton-related genes, macrophage capping protein (CAPG) and leupaxin (LPXN), are modulated by dECM treatments. Using cytoskeleton polymerization modulators and siRNA, we demonstrated that fetal dECM lowers fibroblast differentiation through CAPG.

Role of CPI-17 in the regulation of endothelial cytoskeleton

2004 ◽  
Vol 287 (5) ◽  
pp. L970-L980 ◽  
Author(s):  
Irina A. Kolosova ◽  
Shwu-Fan Ma ◽  
Djanybek M. Adyshev ◽  
Peyi Wang ◽  
Motoi Ohba ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Molecular Mechanisms ◽  
Rho Kinase ◽  
Focal Adhesions ◽  
Endothelial Permeability ◽  
Dominant Negative ◽  
Microvascular Endothelial Cell ◽  
Microvascular Endothelial ◽  
Lung Microvascular Endothelial Cell

We have previously shown that myosin light chain (MLC) phosphatase (MLCP) is critically involved in the regulation of agonist-mediated endothelial permeability and cytoskeletal organization (Verin AD, Patterson CE, Day MA, and Garcia JG. Am J Physiol Lung Cell Mol Physiol 269: L99–L108, 1995). The molecular mechanisms of endothelial MLCP regulation, however, are not completely understood. In this study we found that, similar to smooth muscle, lung microvascular endothelial cells expressed specific endogenous inhibitor of MLCP, CPI-17. To elucidate the role of CPI-17 in the regulation of endothelial cytoskeleton, full-length CPI-17 plasmid was transiently transfected into pulmonary artery endothelial cells, where the background of endogenous protein is low. CPI-17 had no effect on cytoskeleton under nonstimulating conditions. However, stimulation of transfected cells with direct PKC activator PMA caused a dramatic increase in F-actin stress fibers, focal adhesions, and MLC phosphorylation compared with untransfected cells. Inflammatory agonist histamine and, to a much lesser extent, thrombin were capable of activating CPI-17. Histamine caused stronger CPI-17 phosphorylation than thrombin. Inhibitory analysis revealed that PKC more significantly contributes to agonist-induced CPI-17 phosphorylation than Rho-kinase. Dominant-negative PKC-α abolished the effect of CPI-17 on actin cytoskeleton, suggesting that the PKC-α isoform is most likely responsible for CPI-17 activation in the endothelium. Depletion of endogenous CPI-17 in lung microvascular endothelial cell significantly attenuated histamine-induced increase in endothelial permeability. Together these data suggest the potential importance of PKC/CPI-17-mediated pathway in histamine-triggered cytoskeletal rearrangements leading to lung microvascular barrier compromise.

scholarly journals Targeting and transport: How microtubules control focal adhesion dynamics

2012 ◽  
Vol 198 (4) ◽  
pp. 481-489 ◽  
Author(s):  
Samantha Stehbens ◽  
Torsten Wittmann
Keyword(s):  
Extracellular Matrix ◽  
Cell Migration ◽  
Focal Adhesion ◽  
Molecular Mechanisms ◽  
Rho Gtpase ◽  
Focal Adhesions ◽  
Matrix Metalloproteases ◽  
Force Generation ◽  
Diverse Group ◽  
Directional Cell Migration

Directional cell migration requires force generation that relies on the coordinated remodeling of interactions with the extracellular matrix (ECM), which is mediated by integrin-based focal adhesions (FAs). Normal FA turnover requires dynamic microtubules, and three members of the diverse group of microtubule plus-end-tracking proteins are principally involved in mediating microtubule interactions with FAs. Microtubules also alter the assembly state of FAs by modulating Rho GTPase signaling, and recent evidence suggests that microtubule-mediated clathrin-dependent and -independent endocytosis regulates FA dynamics. In addition, FA-associated microtubules may provide a polarized microtubule track for localized secretion of matrix metalloproteases (MMPs). Thus, different aspects of the molecular mechanisms by which microtubules control FA turnover in migrating cells are beginning to emerge.

Multiscale Stress Analysis of Sheared and Focally-Adhered Endothelial Cells: Role of Subcellular Matrix Moduli in Focal Adhesion-Mediated Signaling

2007 ◽  
Author(s):  
Peter J. Butler ◽  
Amit Bhatnagar ◽  
Michael Ferko
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Cell Activation ◽  
Fluid Shear Stress ◽  
Cell Model ◽  
Focal Adhesions ◽  
Endothelial Cell Activation ◽  
Element Analysis ◽  
Coupling Variables

Focal adhesions (FAs) and their associated integrins are thought to act as mechanosensors and transducers of shear stress into intracellular biochemical signals. However, to date there exists no quantification of the magnitude of forces generated at integrin molecules in response to apically-applied fluid shear stress. Thus, we used finite element analysis of fluid dynamics and cellular stresses to compute FA stresses from solid models of focally-adhered endothelial cells. These models were developed from quantitative 3-D microscopy and total internal reflection fluorescence (TIRF) microscopy of calcein-stained endothelial cells. Extrusion coupling variables mapped stresses from the macroscale cell model to individual microscale 3-D models of FAs determined from quantitative TIRF. Included in the microscale FA model were moduli for subcellular matrix (SCM) (e.g. hyaluronan, hyaluronaic acid and other glycocalyx constituents) and extracellular matrix (ECM) (e.g. collagen, fibronectin). Integrin forces were estimated from assumed bonds densities and computed FA stresses. Maximal bond tension obtained from the simulation for a single integrin-extracellular matrix (ECM) bond was .1pN. Thus, it is unlikely that integrin-ECM bonds or chemical activities are appreciably affected by shear stress. The computational model, however, supports an alternative model of activation in and reorganization of FAs in which shear stress-induced forces cause the membrane to bend toward and away from the ECM immediately upstream and downstream of the FA, respectively. The simulation also suggests that the elasticity of the SCM plays an important role in modulating shear-induced FA reorganization. These results support a new model of endothelial cell activation by shear stress in which integrins and FAs participate in the directional biasing of force-induce signaling but do not initiate it.

scholarly journals Vascular cell-matrix adhesion in development and cancer

2021 ◽  
Author(s):  
Christina Arapatzi ◽  
Georgia Rouni ◽  
Vassiliki Kostourou
Keyword(s):  
Endothelial Cells ◽  
Molecular Mechanisms ◽  
Notch Signalling ◽  
Tumour Angiogenesis ◽  
Genetic Studies ◽  
Cell Matrix ◽  
Vascular Morphogenesis ◽  
Current State ◽  
Cell Matrix Adhesion

The development and homeostasis of vertebrate organisms depend on the “tree of life”, that is the intricate network of vascular tubes composed by endothelial cells attached to the basement membrane and surrounded by perivascular cells. Although many studies have revealed the fundamental role of cytokines, growth factors and Notch signalling in vascular morphogenesis, we still lack sufficient understanding of the molecular mechanisms controlling the various steps of the angiogenic processes. Emerging data highlight that cell adhesions are key players in vascular morphogenesis. In this review, we focus on endothelial cells and we present the current state of knowledge regarding the role of cell-matrix adhesions in developmental and tumour angiogenesis, attained mainly from genetic studies and animal models.

scholarly journals Actin Dynamics Associated with Focal Adhesions

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Corina Ciobanasu ◽  
Bruno Faivre ◽  
Christophe Le Clainche
Keyword(s):  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Body Force ◽  
Focal Adhesions ◽  
Stress Fibers ◽  
Actin Dynamics ◽  
Actin Assembly ◽  
Force Transmission ◽  
Cell Matrix ◽  
Cell Matrix Adhesion

Cell-matrix adhesion plays a major role during cell migration. Proteins from adhesion structures connect the extracellular matrix to the actin cytoskeleton, allowing the growing actin network to push the plasma membrane and the contractile cables (stress fibers) to pull the cell body. Force transmission to the extracellular matrix depends on several parameters including the regulation of actin dynamics in adhesion structures, the contractility of stress fibers, and the mechanosensitive response of adhesion structures. Here we highlight recent findings on the molecular mechanisms by which actin assembly is regulated in adhesion structures and the molecular basis of the mechanosensitivity of focal adhesions.

Abstract P387: Deceasing Tissue Stiffness Improves The Efficacy Of Extracellular Matrix-based Therapy For Myocardial Infarction

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Xinming Wang ◽  
Samuel Senyo
Keyword(s):  
Myocardial Infarction ◽  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Heart Function ◽  
Extracellular Proteins ◽  
Molecular Evidence ◽  
Mouse Heart ◽  
Heart Regeneration ◽  
Tissue Stiffness ◽  
Post Injury

Hypothesis and objective: We hypothesize that lowering heart stiffness improves heart regeneration induced by extracellular matrix (ECM) proteins. In this study we investigated heart post-injury responses in non-regenerative mice hearts with modulated tissue stiffness and ECM hydrogel. The objectives are 1) determining if heart stiffness affects heart regeneration in response to extracellular biomolecules; and 2) identifying specific signaling pathways that regulate fibroblasts and cardiomyocytes mechanosensitivity to extracellular proteins. Methods: P5 mouse heart stiffness was modulated by BAPN and genipin injections. Solubilized porcine fetal ECM was injected immediately after ligating coronary artery. Heart function and histology were conducted on day 3 and week 3 post-myocardial infarction (MI). A mice ventricle explant model was used to investigate the molecular mechanisms. Results: Heart stiffness was lowered from 50kPa to 9kPa by BAPN and increased to 142kPa by genipin. We observed that fetal ECM treatment preserved cardiac output, reduced fibrosis, and promoted cardiomyocyte cell cycle activity. Decreasing tissue stiffness further improved the therapeutic efficacy of fetal ECM on heart post-MI response (Fig.1). Decreasing tissue stiffness lowered fibrosis in non-ECM treated MI control hearts, but did not affect the other aspects. Using a ventricle explant model of various stiffness, molecular evidence demonstrated that agrin-YAP signaling pathway is involved in the mechano-regulation of fetal ECM-induced heart regeneration. Agrin expression was elevated and cardiomyocyte YAP activation was not affected by changing tissue stiffness in control (no-ECM) mechano-modulated explants. However, YAP activation in fetal-ECM treated explants was increased by softening tissue. We also demonstrated that ECM hydrogel inhibits fibroblast to myofibroblast differentiation through CAPG protein.

Response of an Actin Filament Network Model Under Cyclic Stretching Through a Coarse Grained Monte Carlo Approach

2010 ◽  
Author(s):  
John Kang ◽  
Robert L. Steward ◽  
YongTae Kim ◽  
Russell Schwartz ◽  
Kathleen M. Puskar ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Monte Carlo ◽  
Cell Structure ◽  
Focal Adhesions ◽  
Coarse Grained ◽  
Mechanical Interaction ◽  
Cyclic Stretching ◽  
Cellular Junctions ◽  
Filament Network

The cytoskeleton is a dynamic system linked to the cell’s environment through sites of potential mechanical interaction such as focal adhesions, integrins, cellular junctions, and the extracellular matrix. The physiologic mechanical stimulation experienced by cells such as endothelial cells is comprised of multiple mechanical modes (e.g., stretching and shear), thus presenting a challenge to characterize their influence on cell structure.

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