Posts Tagged: endothelial cells

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Mural cells derived from endocardium in developing heart. A and B, Endocardial cells undergo endothelial to mesenchymal transition to form PDGFRβ+PDGFRα+NG2– mesenchymal cells in the cardiac cushion (black arrows). C and D, Mesenchymal cells migrate into myocardium (white arrows) to form PDGFRβ+PDGFRα–NG2+αSMA+ smooth muscle cells or PDGFRβ+PDGFRα–NG2+αSMA– pericytes. [Powerpoint File]

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Molecular regulation of endocardial cushion endothelial to mesenchymal transition (EndoMT). Multiple signaling pathways including BMP (bone morphogenetic protein), TGFβ (transforming growth factor-β), and Notch control endocardial contribution to cushion morphogenesis through regulating EndoMT. AVC indicates atrioventricular canal; Msx, msh homeobox; OFT, outflow tract; Rbpj, recombination signal binding protein for immunoglobulin kappa J region; Slug, snail family zinc finger 2; Snail, snail family zinc finger 1; and Twist, twist basic helix–loop–helix transcription factor. [Powerpoint File]

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Schematic showing the endocardial cell plasticity. Endocardial cell (in the center) differentiates into hematopoietic cell, cushion mesenchyme, coronary, liver vascular endothelial cell, and cardiomyocyte (arrows). Question (?) indicates that the cardiomyocyte fate needs validated. Endocardial cell also contributes to fibroblast, adipocyte, pericyte, and smooth muscle cell (dotted arrows), which might be through intermediate stage of mesenchymal cell. [Powerpoint File]

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Endothelial–cardiomyocyte interplay through paracrine factors. Endothelial cell NO increases basal contractility via nitrosylation of L-type Ca2+ channel (LTCC) and ryanodine receptor (RyR2). NO attenuates β-adrenergic effects on cardiomyocyte excitation–contraction coupling via cGMP-dependent degradation of cAMP and protein kinase G (PKG)-mediated decrease of LTCC activity. PKG also phosphorylates troponin I, leading to myofilament calcium desensitization and thus increased lusitropy. Endothelin-1, which mainly acts through the endothelin A (ETA) receptor in ventricular cardiomyocytes, may increase calcium entry via protein kinase C (PKC)-mediated (1) increase of LTCC activity, (2) indirect activation of sodium–calcium exchanger (NCX) reverse mode by increasing Na+–H+ exchanger activity, and (3) direct activation of NCX reverse (shown) and forward (not shown) mode. Endothelin-1 alters myofilament Ca2+ sensitivity via protein kinase C/D (PKC/D) phosphorylation of troponin I and myosin-binding protein C. Finally, endothelin-1 may increase calcium-induced calcium release via inositol trisphosphate (IP3) activation of inositol trisphosphate receptor (IP3R), which sensitizes RyR2 on the sarcoplasmic reticulum (SR). Green and red arrows denote activation and inhibition, respectively. PLB indicates phospholamban; and SERCA, sarcoendoplasmic reticulum Ca2+-ATPase. [Powerpoint File]

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Human engineered cardiac tissue (hECT) contractility assay. A, hECTs are created, cultured, and tested in a custom bioreactor with integrated force-sensing end-posts; as the tissue beats, deflections of the end-posts are tracked. Output contractile metrics include, but are not limited to, developed force (DF), maximum rates of contraction and relaxation (+/− dF/dt, respectively), and beat rate. B, Confocal microscopy of hECTs labeled with cardiac troponin I (green) and DAPI (4’,6-diamidino-2-phenylindole; blue) displays cardiomyocytes with striated sarcomeres and regions of aligned myofibrils. Inset shows magnified view of registered sarcomeres. C, hECT labeled with sarcoendoplasmic reticulum Ca2+-ATPase 2 (red) and DAPI (blue) shows sarcoplasmic reticulum structures distributed throughout the tissue. Bar = 40 µm. [Powerpoint File]

Multifunctional Role of Chymase in Acute and Chronic Tissue Injury and Remodeling

Multifunctional Role of Chymase in Acute and Chronic Tissue Injury and Remodeling

Louis J. Dell’Italia, James F. Collawn, Carlos M. Ferrario

Evidence from human pathology and preclinical animal models supports the important role for chymase in cardiovascular stress. Upper left, Demonstrates a cross-section of a human renal artery with marked increase in chymase (brown) extending from the endothelium to adventitia in a patient with diabetes mellitus (reprinted from Koka et al60 with permission. Copyright ©2006, Wolters Kluwer Health). Center and upper right, Cartoons demonstrate the potential role of chymase in attenuating ischemia/reperfusion injury and promoting stabilization of the vulnerable atherosclerotic plaque (reprinted from Bentzon et al249 with permission. Copyright ©2014, Wolters Kluwer Health). Bottom right, Demonstrate the marked increase in left ventricular (LV) volume and LV wall thinning in a patient with chronic mitral regurgitation (MR; right) compared with a normal subject (left; reprinted from Zheng et al250 with permission. Copyright ©2014, Wolters Kluwer Health). Bottom left, Demonstrates the increase in LV volume and apical wall thinning in a patient 6 mo after an antero-apical myocardial infarction (MI; right) compared with 3 d after MI (left; reprinted from Foster et al251 with permission. Copyright ©1998, Elsevier). Targeting the multifunctional roles of chymase (Figure 2) in each of these conditions by chymase inhibition will complement conventional renin–angiotensin system (RAS) blockade in promoting better outcomes and tissue protection. [Powerpoint File]

Autophagy and Mitophagy in Cardiovascular Disease

Autophagy and Mitophagy in Cardiovascular Disease

José Manuel Bravo-San Pedro, Guido Kroemer, Lorenzo Galluzzi

Detrimental effects of autophagy or mitophagy inhibition on cardiovascular health. Multiple genetic interventions that limit autophagic or mitophagic flux at the whole-body level or in specific compartments of the cardiovascular system have been associated with the spontaneous development of cardiovascular disorders. AP indicates autophagosome; APL, autophagolysosome; Atg5, autophagy related 5; Bnip3l, BCL2 interacting protein 3 like; Dnml1, dynamin 1 like; Fbxo32, F-box protein 32; L, lysosome; Lamp2, lysosomal-associated membrane protein 2; Mfn1, mitofusin 1; Park2, Parkinson disease (autosomal recessive, juvenile) 2, parkin; Pink1, PTEN-induced putative kinase 1; Sirt6, sirtuin 6; Tfrc, transferrin receptor; and Trp53, transformation-related protein 53. [Powerpoint File]

Extracellular Vesicles in Angiogenesis

Extracellular Vesicles in Angiogenesis

Dilyana Todorova, Stéphanie Simoncini, Romaric Lacroix, Florence Sabatier, Françoise Dignat-George

Mechanisms involved in the modulation of Angiogenesis by endothelial cell (EC)–derived extracellular vesicles (EVs). EC release EVs rich in micro-RNA such as miR-214 and miR-126, that are transferred to recipient EC and induce proangiogenic signaling. EVs contain functional matrix metalloproteinases that facilitate angiogenesis through the degradation of components of the extracellular matrix. Dll4 is transferred to EC by the EVs and induces Notch receptor internalization and tip cell formation. EVs bear, at their surface, a tissue factor that interacts with β1 integrin and induces Rac1-ERK1/2-ETS1 signaling, leading to the increased secretion of CCL2. EVs transport the complex uPA/uPAR, which stimulates angiogenesis through plasmin generation. The phosphatidylserine present on the surface of the EVs interacts with CD36 and induces Fyn kinase signaling, which leads to increased oxidative stress and the inhibition of angiogenesis. ATM indicates ataxia telangiectasia mutated; CCl2, chemokine c-c motif ligand 2; Dll4, Delta-like 4; ECM, extracellular matrix; ERK1/2, extracellular signal-related kinase 1 and 2; ETS1, avian erythroblastosis virus E26 homolog-1; IL-3R, interleukin-3 receptor; MMPs, matrix metalloproteinases; NotchR, Notch receptor; PS, phosphatidylserine; Rac1, Ras-related C3 botulinum toxin substrate 1; ROS, reactive oxygen species; TF, tissue factor; TIMPS, tissue inhibitor of metalloproteinases; uPA, urokinase plasminogen activator; and uPAR, urokinase plasminogen activator receptor. [Powerpoint File]

Extracellular Vesicles in Angiogenesis

Extracellular Vesicles in Angiogenesis

Dilyana Todorova, Stéphanie Simoncini, Romaric Lacroix, Florence Sabatier, Françoise Dignat-George

Mechanisms involved in the modulation of Angiogenesis by platelet-derived extracellular vesicles (EVs). Platelet-derived EVs contain various growth factors and chemokines that induce proangiogenic signaling in endothelial cell (EC). Spingosine-1-phosphate (S1P1), present on the EV surface, induces PI3K activation and, together with VEGF and bFGF, promotes angiogenesis. The EVs released by platelets stimulate the proangiogenic potential of circulating angiogenic cells by increasing their expression of both membrane molecules and soluble factors. Platelet-derived EVs can inhibit angiogenesis by transferring the p22phox and gp91 subunits of NADPH oxidase and increasing the oxidative stress in EC. ? indicates that the exact content of the EVs is not reported; bFGF, basic fibroblast growth factor; EGF, epidermal growth factor; GM-CSF, granulocyte-macrophage colony-stimulating factor; HGF, hepatocyte growth factor; NADPH, nicotinamide adenine dinucleotide phosphate; PI3K, phosphoinositide 3-kinase; RANTES, regulated on activation, normal T-cell–expressed and secreted; ROS, reactive oxygen species; VEGF, vascular endothelial growth factor; and VEGFR, vascular endothelial growth factor receptor. [Powerpoint FIle]

Contemporary Approaches to Modulating the Nitric Oxide–cGMP Pathway in Cardiovascular Disease

Contemporary Approaches to Modulating the Nitric Oxide–cGMP Pathway in Cardiovascular Disease

Jan R. Kraehling, William C. Sessa

Proteins and enzymes involved in the nitric oxide (NO)-nitric oxide–sensitive guanylate cyclase (NOsGC)–cGMP pathway and its modulators. Key players of the pathway are shown in blue, the positive modulators are shown in yellow, and the negative modulators in purple. Endothelial cells (EC) are shown in green (top), whereas the vascular smooth muscle cell (VSMC) is shown in red (bottom). The space between the 2 cells is called myoendothelial junction (MEJ). cGMP mediates its cellular functions through cGMP-modulated (cyclic nucleotide-gated [CNG]) cation channels, cGMP-dependent protein kinases (cGKs) and cGMP-regulated phosphodiesterases (PDEs). BH4 indicates tetrahydrobiopterin; CAV1, caveolin-1; CYB5R3, NADH-cytochrome b5 reductase 3; eNOS, endothelial nitric oxide synthase (NOS3); Hb2+/Hb3+, hemoglobin α (reduced/oxidized); and PDE, phosphodiesterase. [Powerpoint File]

Contemporary Approaches to Modulating the Nitric Oxide–cGMP Pathway in Cardiovascular Disease

Contemporary Approaches to Modulating the Nitric Oxide–cGMP Pathway in Cardiovascular Disease

Jan R. Kraehling, William C. Sessa

Mechanism of action of nitric oxide–sensitive guanylate cyclase (NOsGC) stimulators and activators. NOsGC stimulators bind to the enzyme and act in an allosteric manner. NO and NOsGC stimulators enhance the NOsGC activity synergistically. NOsGC activators occupy the heme binding site and work therefore only additively with NO. The oxidation of the heme-Fe2+ to heme-Fe3+ results in a weaker binding of heme to NOsGC, hence allowing the NOsGC activators to occupy the heme binding site easier. The schematic is derived from Zorn and Wells.111 [Powerpoint File]

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Yulia A. Komarova, Kevin Kruse, Dolly Mehta, Asrar B. Malik

Mechanotransduction at adherens junctions (AJs). The mechanosensory complex in endothelial cells is composed of vascular endothelial (VE)-cadherin, platelet endothelial cell adhesion molecule (PECAM)-1, and vascular endothelial growth factor receptor (VEGFR) 2. Mechanosensing of shear stress occurs through PECAM-1–dependent activation of Fyn, which in turn facilitates VEGFR2-mediated signaling in a ligand-independent manner and activates phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K). PI3K activates both Rac1 and endothelial nitric oxide synthase (eNOS) signaling pathways. Rac1 relieves tension at AJs, whereas NO concomitantly promotes vasorelaxation of smooth muscle cells. PECAM-1–dependent sensing of shear stress also promotes α2β1 integrin signaling and consequently activation of protein kinase A (PKA) in atheroresistant regions. PKA phosphorylates RhoA and decreases RhoA-dependent cellular stiffness allowing the endothelial cell to align in the direction of blood flow. GPCR indicates G-protein–coupled receptor; and sGC, soluble guanylyl cyclase. [Powerpoint File]

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Yulia A. Komarova, Kevin Kruse, Dolly Mehta, Asrar B. Malik

Role of actomyosin apparatus in stabilizing adherens junctions (AJs). A, Domain structure of nonmuscle myosin-II (NM-II). The NM-II consists of a globular head domain containing both actin-binding and motor domains, essential light chains (ELCs), regulatory light chains (RLCs), and heavy chains. NM-II possesses a head-to-tail interaction in the absence of phosphorylation. Phosphorylation of regulatory light chain at Thr18/Ser19 by myosin light chain kinase (MLCK) unfolds the molecule, enabling assembly of antiparallel filaments through interactions between their rod domains. Activation of Rho-associated kinase (ROCK), which inhibits phosphatase activity of myosin light chain phosphatase (MLCP) in a phosphorylation-dependent manner, also favors RLC phosphorylation. NM-II filaments bind to actin filaments, which slide along each other, and cause a cell contraction. Modified from Vicente-Manzanares et al415 with permission of the publisher. Copyright ©2009, Nature Publishing Group. B, Proposed mechanism of regulation of NM-II activity at AJs in confluent endothelium. NM-II regulates attachment of the vascular endothelial (VE)-cadherin adhesion complex to the actin cytoskeleton, thereby generating mechanical tension required for binding of α-catenin to both β-catenin and f-actin. NM-II phosphorylation is controlled by MLCK and MLCP activities. In the model, we propose that Src and Cdc42 pathways cooperate in regulating NM-II activity at AJs. Cdc42 facilitates activation of NM-II through myotonic dystrophy kinase–related Cdc42-binding kinase (MRCK)–dependent phosphorylation of MLCP, whereas Src phosphorylates MLCK at sites of VE-cadherin adhesion. CaM indicates calmodulin; GAP, GTPase-activating protein; and GEF, guanine nucleotide exchange factor. [Powerpoint File]

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Protein Interactions at Endothelial Junctions and Signaling Mechanisms Regulating Endothelial Permeability

Yulia A. Komarova, Kevin Kruse, Dolly Mehta, Asrar B. Malik

Composition of interendothelial junctions. A, Schematic representation of interendothelial junctions composed of tight junctions (TJs), adherens junctions (AJs), and gap junctions (GJs). TJs are mediated by adhesion proteins such as claudins, occludin, and junctional adhesion molecules (JAMs), whereas the zona occludin proteins (ZO-1, ZO-2, and ZO-3) connect adhesion molecules to the actin cytoskeleton. AJs are composed of vascular endothelial (VE)-cadherin and associated β- and p120-catenins. α-catenin binds β-catenin to connect AJs to the actin cytoskeleton. GJs are composed of 2 connexin hexamers forming hemichannels. B, VE-cadherin mediates adhesion by trans-dimerization of tryptophan 2 and tryptophan 4 residues in a hydrophobic pocket of the opposing VE-cadherin molecule. Ribbon presentations of VE-cadherin trans-dimer. C, Strand swap dimerization occurs through the insertion of a tryptophan residue into the hydrophobic binding pocket of the opposing cadherin. D, Trans-dimerization (between endothelial cell [EC] 1 and EC1 of opposing cadherins) orients VE-cadherin molecules and facilitates cis interactions (between EC1 and EC2 of neighboring cadherins). Panels B, C, and D are modified from Brasch et al115 with permission of the publisher. Copyright ©2012, Elsevier. [Powerpoint File]

Endothelial Cell Dysfunction and the Pathobiology of Atherosclerosis

Endothelial Cell Dysfunction and the Pathobiology of Atherosclerosis

Michael A. Gimbrone Jr, Guillermo García-Cardeña

Endothelial-derived nitric oxide: production and biological actions. Endothelial cells rapidly produce nitric oxide (NO) via a unique isoform of NO synthase (eNOS) in response to agonists (eg, acetylcholine and bradykinin) and fluctuations in blood flow. Once generated, NO rapidly diffuses through the endothelial plasma membrane to activate guanylate cyclase in several cell types present in the blood (platelets and leukocytes) and also within the vessel wall (smooth muscle). Activation of guanylate cyclase in platelets results in inhibition of activation, adhesion, and aggregation; in leukocytes, decreased adhesivity; in smooth muscle cells, dephosphorylation of myosin light chain and vasorelaxation. NO also reacts with hemoglobin in erythrocytes, enhancing oxygen delivery to tissues. Chronic exposure of endothelial cells to laminar flow results in transcriptional upregulation of eNOS, thus increasing their NO-forming capacity (Illustration Credit: Ben Smith). [Powerpoint File]