Fibronectin receptor integrin α5β1 regulates assembly of PP2A complexes through PDE4D: modulation of vascular inflammation and atherosclerosis

AbstractFibronectin in the vascular wall promotes inflammatory activation of the endothelium during vascular remodeling and atherosclerosis. These effects are mediated in part by fibronectin binding to integrin α5, which recruits and activates phosphodiesterase 4D5 (PDE4D5) by inducing its dephosphorylation on an inhibitory site Ser651. Active PDE then hydrolyzes anti-inflammatory cAMP to facilitate inflammatory signaling. To test this model in vivo, we mutated the integrin binding site in PDE4D5 in mice. This mutation reduced endothelial inflammatory activation in athero-prone regions of arteries, and, in a hyperlipidemia model, reduced atherosclerotic plaque size while increasing markers of plaque stability. We then investigated the mechanism of PDE4D5 activation. Proteomics identified the PP2A regulatory subunit B55α as the factor recruiting PP2A to PDE4D5. The B55α-PP2A complex localized to adhesions and directly dephosphorylated PDE4D5. This interaction also unexpectedly stabilized the PP2A-B55α complex. The integrin-regulated, pro-atherosclerotic transcription factor Yap is also dephosphorylated and activated through this pathway. PDE4D5 therefore mediates matrix-specific regulation of EC phenotype via an unconventional adapter role, assembling and anchoring a multifunctional PP2A complex with other targets. These results are likely to have widespread consequences for control of cell function by integrins.

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Heart rate reduction with ivabradine promotes shear stress-dependent anti-inflammatory mechanisms in arteries

Thrombosis and Haemostasis ◽

10.1160/th16-03-0214 ◽

2016 ◽

Vol 116 (07) ◽

pp. 181-190 ◽

Cited By ~ 13

Author(s):

Luong Le ◽

Hayley Duckles ◽

Torsten Schenkel ◽

Marwa Mahmoud ◽

Jordi Tremoleda ◽

...

Keyword(s):

Heart Rate ◽

Shear Stress ◽

Carotid Arteries ◽

Vascular Inflammation ◽

Protective Effects ◽

En Face ◽

Inflammatory Activation ◽

Anti Inflammatory ◽

Stress Dependent

SummaryBlood flow generates wall shear stress (WSS) which alters endothelial cell (EC) function. Low WSS promotes vascular inflammation and atherosclerosis whereas high uniform WSS is protective. Ivabradine decreases heart rate leading to altered haemodynamics. Besides its cardio-protective effects, ivabradine protects arteries from inflammation and atherosclerosis via unknown mechanisms. We hypothesised that ivabradine protects arteries by increasing WSS to reduce vascular inflammation. Hypercholesterolaemic mice were treated with ivabradine for seven weeks in drinking water or remained untreated as a control. En face immunostaining demonstrated that treatment with ivabradine reduced the expression of pro-inflammatory VCAM-1 (p<0.01) and enhanced the expression of anti-inflammatory eNOS (p<0.01) at the inner curvature of the aorta. We concluded that ivabradine alters EC physiology indirectly via modulation of flow because treatment with ivabradine had no effect in ligated carotid arteries in vivo, and did not influence the basal or TNFα-induced expression of inflammatory (VCAM-1, MCP-1) or protective (eNOS, HMOX1, KLF2, KLF4) genes in cultured EC. We therefore considered whether ivabradine can alter WSS which is a regulator of EC inflammatory activation. Computational fluid dynamics demonstrated that ivabradine treatment reduced heart rate by 20 % and enhanced WSS in the aorta. In conclusion, ivabradine treatment altered haemodynamics in the murine aorta by increasing the magnitude of shear stress. This was accompanied by induction of eNOS and suppression of VCAM-1, whereas ivabradine did not alter EC that could not respond to flow. Thus ivabradine protects arteries by altering local mechanical conditions to trigger an anti-inflammatory response.

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Biaxial elastic properties of rat arteries in vivo: influence of vascular wall cells on anisotropy

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1994.267.2.h574 ◽

1994 ◽

Vol 267 (2) ◽

pp. H574-H579 ◽

Cited By ~ 4

Author(s):

G. J. L'Italien ◽

N. R. Chandrasekar ◽

G. M. Lamuraglia ◽

W. C. Pevec ◽

S. Dhara ◽

...

Keyword(s):

Elastic Modulus ◽

Poisson’S Ratio ◽

Carotid Arteries ◽

Cell Function ◽

Vascular Wall ◽

Poisson's Ratio ◽

Vascular Cell ◽

Longitudinal Modulus ◽

Nonlinearly Elastic

There is no consensus as to the degree of arterial anisotropy or to its relationship to vascular cell function. Given the relevance of the isotropic assumption in formulating elasticity models, reliable measures of biaxial displacements are needed. In this study, a video motion analyzer (VMA) was used to describe the biaxial in vivo dynamic elasticity of 22 carotid arteries and 5 abdominal aortas in 27 rats. The influence of vascular cell function was also examined by subjecting six rats to a photosensitive drug, chloroaluminum sulfonated phthalocyanine (CASPc), which is focally cytotoxic on activation by laser. Circumferential compliance (Ccirc) was greater than longitudinal compliance (Clong) for all vessels. Compliance pressure curves were nonlinear, and biaxial displacements were in phase. The circumferential elastic modulus was less than the longitudinal modulus at common stresses. CASPc + laser reduced Ccirc but not Clong, thus altering Poisson's ratio. In conclusion, rat arteries are biaxially, nonlinearly elastic and anisotropic in vivo. Vascular cells modulate Poisson's ratio by influencing Ccirc.

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p85β regulatory subunit of class IA PI3 kinase negatively regulates mast cell growth, maturation, and leukemogenesis

Blood ◽

10.1182/blood-2011-05-355602 ◽

2012 ◽

Vol 119 (17) ◽

pp. 3951-3961 ◽

Cited By ~ 9

Author(s):

Subha Krishnan ◽

Raghuveer Singh Mali ◽

Baskar Ramdas ◽

Emily Sims ◽

Peilin Ma ◽

...

Keyword(s):

Mast Cell ◽

Mast Cells ◽

Cell Function ◽

Receptor Internalization ◽

Regulatory Subunit ◽

Growth Defects ◽

Microphthalmia Transcription Factor ◽

Carboxy Terminal

Abstract We show that loss of p85α inhibits the growth and maturation of mast cells, whereas loss of p85β enhances this process. Whereas restoring the expression of p85α in P85α−/− cells restores these functions, overexpression of p85β has the opposite effect. Consistently, overexpression of p85β in WT mast cells represses KIT-induced proliferation and IL-3–mediated maturation by inhibiting the expression of Microphthalmia transcription factor. Because p85α and p85β differ in their N-terminal sequences, chimeric proteins consisting of amino or carboxy-terminal of p85α and/or p85β do not rescue the growth defects of p85α−/− cells, suggesting cooperation between these domains for normal mast cell function. Loss of p85β impaired ligand induced KIT receptor internalization and its overexpression enhanced this process, partly because of increased binding of c-Cbl to p85β relative to p85α. In vivo, loss of p85β resulted in increased mast cells, and bone marrow transplantation of cells overexpressing p85β resulted in significant reduction in some tissue mast cells. Overexpression of p85β suppressed the growth of oncogenic KIT-expressing cells in vitro and prolonged the survival of leukemic mice in vivo. Thus, p85α and p85β differentially regulate SCF and oncogenic KIT-induced signals in myeloid lineage-derived mast cells.

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The P387 Thrombospondin-4 Variant Promotes Accumulation of Macrophages in Atherosclerotic Lesions

10.1101/666602 ◽

2019 ◽

Author(s):

Santoshi Muppala ◽

Mohammed Tanjimur Rahman ◽

Irene Krukovets ◽

Dmitriy Verbovetskiy ◽

Elzbieta Pluskota ◽

...

Keyword(s):

Cardiovascular Disease ◽

Smooth Muscle Actin ◽

Vascular Inflammation ◽

Cutting Temperature ◽

Vascular Wall ◽

Alpha Smooth Muscle Actin ◽

Knock Out ◽

Atherosclerotic Lesions ◽

Thrombospondin 4

AbstractAimsThrombopspondin-4 (TSP4) is a pro-angiogenic protein that has been implicated in tissue remodeling and local vascular inflammation. TSP4 and, in particular, its SNP variant, P387 TSP4, have been associated with cardiovascular disease.Macrophages are central to initiation and resolution of inflammation and development of atherosclerotic lesions, but the effects of the P387 TSP4 on macrophages remain essentially unknown. We examined the effects of the P387 TSP4 variant on macrophages in cell culture andin vivoin a murine model of atherosclerosis. Further, the levels and distributions of the twoTSP4 variants were assessed in human atherosclerotic arteries.Methods and ResultsInApoE−/−/P387-TSP4 knock-in mice, atherosclerotic lesions accumulated more macrophages than lesions bearing A387 TSP4. The levels of inflammatory markers were increased in lesions ofApoE−/−/P387-TSP4 knock-in mice compared toApoE−/−mice. Lesions in human arteries from individuals carrying the P387 variant had higher levels of TSP4 and higher macrophage accumulation. P387 TSP4 was more active in supporting adhesion of cultured human and mouse macrophages in experiments using recombinant TSP4 variants and in cells derived from P387-TSP4 knock-in mice.ConclusionsTSP4 supports the adhesion of macrophages and their accumulation in atherosclerotic lesions. P387 TSP4 is more active in supporting these pro-inflammatory events in the vascular wall, which may contribute to the increased association of P387 TSP4 with cardiovascular disease.AbbreviationsBSA, bovine serum albumin; DMSO, dimethyl sulfoxide; ECM, extracellular matrix;Thbs4−/−, thrombospondin-4 gene knock-out; WT, wild type; P387-TSP4 KI, P387TSP4knock-in mice; OCT, Optimum Cutting Temperature; vWF, von Willebrand factor; α-SMA, alpha-smooth muscle actin; Egr2, Early Growth Response 2; PBS, Phosphate Buffer saline; DMEM, Dulbecco’s Modified Eagle Medium.

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Leukotriene Receptors: Crucial Components in Vascular Inflammation

The Scientific World JOURNAL ◽

10.1100/tsw.2007.187 ◽

2007 ◽

Vol 7 ◽

pp. 1422-1439 ◽

Cited By ~ 30

Author(s):

Magnus Bäck

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Vascular Inflammation ◽

Vascular Wall ◽

Receptor Activation ◽

Receptor Expression ◽

Surface Receptors ◽

Beneficial Effects

The accumulation of immune cells during vascular inflammation leads to formation of leukotrienes (LTs). While macrophages represent a major source of LT biosynthesis in the proximity of the vascular wall, activated T lymphocytes may, in addition, play a key regulatory role on macrophage expression of LT-forming enzymes. Within the vascular wall, LTs activate cell surface receptors of the BLT and CysLT subtypes expressed on vascular smooth muscle and endothelial cells. The LT receptor expression on those cells is highly dependent on transcriptional regulation by pro- and anti-inflammatory mediators. LT receptor activation on vascular smooth muscle cells is associated with both directly and indirectly induced vasoconstriction, as well as intimal hyperplasia through stimulation of migration and proliferation. On the other hand, endothelial LT receptors induce vasorelaxation and leukocyte recruitment and adhesion. Results fromin vitroandin vivostudies of LT receptor antagonists indicate potential beneficial effects in atherosclerosis and other inflammatory cardiovascular diseases.

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Structure of the phosphoinositide 3-kinase p110γ-p101 complex reveals molecular mechanism of GPCR activation

10.1101/2021.06.01.446612 ◽

2021 ◽

Author(s):

Manoj K Rathinaswamy ◽

Udit Dalwadi ◽

Kaelin D Fleming ◽

Carson Adams ◽

Jordan TB Stariha ◽

...

Keyword(s):

Cell Function ◽

Immune Cell ◽

Inflammatory Diseases ◽

Regulatory Subunit ◽

Regulatory Subunits ◽

Gpcr Activation ◽

Oncogenic Mutations ◽

Phosphoinositide 3 Kinase ◽

G Protein Coupled

The class IB phosphoinositide 3-kinase (PI3K), PI3Kγ, is a master regulator of immune cell function, and a promising drug target for both cancer and inflammatory diseases. Critical to PI3Kγ function is the association of the p110γ catalytic subunit to either a p101 or p84 regulatory subunit, which mediates activation by G-protein coupled receptors (GPCRs). Here, we report the cryo-EM structure of a hetero-dimeric PI3Kγ complex, p110γ-p101. This structure reveals a unique assembly of catalytic and regulatory subunits that is distinct from other class I PI3K complexes. p101 mediates activation through its Gβγ binding domain, recruiting the hetero-dimer to the membrane and allowing for engagement of a secondary Gβγ binding site in p110γ. Multiple oncogenic mutations mapped to these novel interfaces and enhanced Gβγ activation. A nanobody that specifically binds to the p101-Gβγ interface blocks activation providing a novel tool to study and target p110γ-p101-specific signaling events in vivo.

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Platelet-vessel wall interactions in atherosclerotic disease

Thrombosis and Haemostasis ◽

10.1160/th07-11-0685 ◽

2008 ◽

Vol 99 (03) ◽

pp. 480-486 ◽

Cited By ~ 116

Author(s):

Harald Langer ◽

Meinrad Gawaz

Keyword(s):

Platelet Adhesion ◽

Plaque Rupture ◽

Vascular Inflammation ◽

Atherosclerotic Lesion ◽

Vascular Wall ◽

Atherosclerotic Disease ◽

Proinflammatory Mediators ◽

Negative Feedback Loops ◽

Progression Of Disease

SummaryDuring the prolonged course of atherosclerotic disease,platelets are of central importance as they contribute to the initiation of the disease, to its progression and acute exacerbation but also provide potential regenerative mechanisms. Platelets secrete chemokines and cytokines that mediate vascular inflammation and are in turn activated by substances released from cells of the vascular wall.These interactions represent positive and negative feedback loops, which in case of dysregulation may lead to development and progression of disease. Furthermore, platelet adhesion to the endothelium is critical for the initiation of atherosclerotic lesion formation in vivo. Even prior to endothelial denudation, platelet adhesion governed by disturbed flow at predilection sites for atherosclerosis induces recruitment of proathe- rosclerotic cells and release of proinflammatory mediators from all involved cell types.Finally,the pathogenetic role of platelets for late atheroclerotic events including plaque rupture, microembolism or spasms within the microcirculation is well established. However, increasing evidence indicates that platelets mediate on the other hand potential regenerative mechanisms. Platelets recruit circulating progenitor cells to sites of vascular injury. Furthermore, they influence their biological activity and maturation. Therefore,platelets contribute at all stages of vascular disease by interfering with highly dynamic processes. Understanding interactions of platelets with other circulating cells and the vascular wall is a prerequisite to understand cardiovascular disease and to identify potential therapeutic targets.

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Progestogen effects at vascular level: the endothelial cells

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci.2010.071 ◽

2010 ◽

Vol 3 (3) ◽

Author(s):

Paolo Mannella ◽

Tommaso Simoncini ◽

Andrea Riccardo Genazzani

Keyword(s):

Cardiovascular System ◽

Vascular Tissue ◽

Cell Function ◽

Cardiovascular Effects ◽

Vascular Wall ◽

Experimental Point ◽

Target Tissue ◽

Endothelial Cell Function

AbstractProgesterone and progestogens are active molecules on the cardiovascular system. However, their action is not as well-characterized as the effects of estrogens. Data of the last clinical trials suggest the possibility of harmful cardiovascular effects of progestogens, and the debate on the role of progesterone and progestins on the vascular wall is open. From an experimental point of view, each progestogen presents typical effects on the cardiovascular system and their administration results in diverse modifications of the effects of estrogens, sometimes acting synergically, others being neutral or antagonizing effects of estrogens. In this paper, we review the most important data from in vivo and in vitro studies which have been published on the effects of progesterone and progestogens on vascular cells. Endothelium is a target tissue for sex steroids and progesterone is able to regulate endothelial cell function and morphology. Even if the perfect molecule does not exist, the understanding of the molecular basis of each progestogen in vascular tissue is therefore of paramount importance for the most appropriate use with an optimal cardiovascular profile.

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Statins and Vulnerable Plaque

Current Pharmaceutical Design ◽

10.2174/1381612823666171019161609 ◽

2018 ◽

Vol 23 (46) ◽

pp. 7069-7085 ◽

Cited By ~ 2

Author(s):

Maria Drakopoulou ◽

Konstantinos Toutouzas ◽

Archontoula Michelongona ◽

Dimitrios Tousoulis

Keyword(s):

Statin Therapy ◽

Vulnerable Plaque ◽

Vascular Wall ◽

Statin Treatment ◽

Duration Of Treatment ◽

Fibrous Cap ◽

Plaque Development ◽

Plaque Stabilization ◽

Inflammatory Activation ◽

The One

Background: Atherosclerosis is a systemic, progressive lipid-driven inflammatory disease of the arterial vascular wall leading progressively to plaque development. The vulnerable plaque, the one considered to be the leading cause of cardiovascular events seems to exhibit a large and soft lipid-rich necrotic core covered by a thin and inflamed fibrous cap. Statin treatment is considered as one of the most effective methods for vulnerable plaque stabilization, currently being the principal drug in primary and secondary prevention of cardiovascular disease. Objective: We sought to evaluate the beneficial effect of statins on biological processes involved in the evolution of vulnerable plaques Method: We performed a systematic review of the literature searching MEDLINE via Pubmed for all experimental and human studies implementing statins in vulnerable plaque. Results: Statins seem to have a beneficial role in plaque stabilization and patient outcome. It seems that this effect is mediated by improving endothelial function, decreasing oxidative stress and inflammation, reducing inflammatory activation and inhibiting thrombogenic response. Although these data are quite promising, it remains to be determined the extent of a potent benefit of the pleiotropic effects of statin therapy in clinical setting. Conclusion: Prospective randomized trials should be conducted in order to further elucidate differences among type and dose of statin therapy, duration of treatment and association with LDL levels and clinical outcome.

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Glucolipotoxicity and GLP-1 secretion

BMJ Open Diabetes Research & Care ◽

10.1136/bmjdrc-2020-001905 ◽

2021 ◽

Vol 9 (1) ◽

pp. e001905

Author(s):

Jung-Hee Hong ◽

Dae-Hee Kim ◽

Moon-Kyu Lee

Keyword(s):

Glucose Transporter ◽

Cell Function ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Mrna Levels ◽

Dependent Manner ◽

Gene Expressions ◽

Simultaneous Treatment ◽

L Cells ◽

Triglyceride Accumulation

IntroductionThe concept of glucolipotoxicity refers to the combined, deleterious effects of elevated glucose and/or fatty acid levels.Research design and methodsTo investigate the effects of chronic glucolipotoxicity on glucagon-like peptide-1-(7-36) amide (GLP-1) secretion, we generated glucolipotoxic conditions in human NCI-H716 enteroendocrine cells using either 5 or 25 mM glucose with or without 500 µM palmitate for 72 hours. For in vivo study, we have established a chronic nutrient infusion model in the rat. Serial blood samples were collected for 2 hours after the consumption of a mixed meal to evaluate insulin sensitivity and β-cell function.ResultsChronic glucolipotoxic conditions decreased GLP-1 secretion and the expressions of pCREB, pGSK3β, β-catenin, and TCF7L2 in NCI-H716 cells. Glucolipotoxicity conditions reduced glucose transporter expression, glucose uptake, and nicotinamide-adenine dinucleotide phosphate (NADPH) levels in L-cells, and increased triglyceride accumulation. In contrast, PPARα and ATP levels were reduced, which correlated well with decreased levels of SUR1 and Kir6.2, cAMP contents and expressions of pCAMK2, EPAC and PKA. We also observed an increase in reactive oxygen species production, UCP2 expression and Complex I activity. Simultaneous treatment with insulin restored the GLP-1 secretion. Glucolipotoxic conditions decreased insulin secretion in a time-dependent manner in INS-1 cells, which was recovered with exendin-4 cotreatment. Glucose and SMOFlipid infusion for 6 hours decreased GLP-1 secretion and proglucagon mRNA levels as well as impaired the glucose tolerance, insulin and C-peptide secretion in rats.ConclusionThese results provide evidence for the first time that glucolipotoxicity could affect GLP-1 secretion through changes in glucose and lipid metabolism, gene expressions, and proglucagon biosynthesis and suggest the interrelationship between glucolipotoxicities of L-cells and β-cells which develops earlier than that of L-cells.

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