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Find video protocols related to scientific articles indexed in Pubmed.
Fibroblast growth factor receptor 1 is a key inhibitor of TGF? signaling in the endothelium.
Sci Signal
PUBLISHED: 09-25-2014
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Abnormal vascular homeostasis can lead to increased proliferation of smooth muscle cells and deposition of extracellular matrix, resulting in neointima formation, which contributes to vascular lumen narrowing, a pathology that underlies diseases including transplant vasculopathy, the recurrence of stenosis, and atherosclerosis. Growth of neointima is in part due to endothelial-to-mesenchymal transition (EndMT), a transforming growth factor-? (TGF?)-driven process, which leads to increased numbers of smooth muscle cells and fibroblasts and deposition of extracellular matrix. We reported that endothelial cell-specific knockout of fibroblast growth factor receptor 1 (FGFR1) led to activation of TGF? signaling and development of EndMT in vitro and in vivo. Furthermore, EndMT in human diseased vasculature correlated with decreased abundance of FGFR1. These findings identify FGFR1 as the key regulator of TGF? signaling and EndMT development.
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Interacting mechanisms in the pathogenesis of cardiac allograft vasculopathy.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 06-05-2014
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Cardiac allograft vasculopathy is the major cause of late graft loss in heart transplant recipients. Histological studies of characteristic end-stage lesions reveal arterial changes consisting of a diffuse, confluent, and concentric intimal expansion containing graft-derived cells expressing smooth muscle markers, extracellular matrix, penetrating microvessels, and a host mononuclear cell infiltrate concentrated subjacent to an intact graft-derived luminal endothelial cell lining with little evidence of acute injury. This intimal expansion combined with inadequate compensatory outward remodeling produces severe generalized stenosis extending throughout the epicardial and intramyocardial arterial tree that causes ischemic graft failure. Cardiac allograft vasculopathy lesions affect ?50% of transplant recipients and are both progressive and refractory to treatment, resulting in ?5% graft loss per year through the first 10 years after transplant. Lesions typically stop at the suture line, implicating alloimmunity as the primary driver, but pathogenesis may be multifactorial. Here, we will discuss 6 potential contributors to lesion formation (1) conventional risk factors of atherosclerosis; (2) pre- or peritransplant injuries; (3) infection; (4) innate immunity; (5) T-cell-mediated immunity; and (6) B-cell-mediated immunity through production of donor-specific antibody. Finally, we will consider how these various mechanisms may interact with each other.
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The docking protein FRS2? is a critical regulator of VEGF receptors signaling.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 04-02-2014
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Vascular endothelial growth factors (VEGFs) signal via their cognate receptor tyrosine kinases designated VEGFR1-3. We report that the docking protein fibroblast growth factor receptor substrate 2 (FRS2?) plays a critical role in cell signaling via these receptors. In vitro FRS2? regulates VEGF-A and VEGF-C-dependent activation of extracellular signal-regulated receptor kinase signaling and blood and lymphatic endothelial cells migration and proliferation. In vivo endothelial-specific deletion of FRS2? results in the profound impairment of postnatal vascular development and adult angiogenesis, lymphangiogenesis, and arteriogenesis. We conclude that FRS2? is a previously unidentified component of VEGF receptors signaling.
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Rapamycin antagonizes TNF induction of VCAM-1 on endothelial cells by inhibiting mTORC2.
J. Exp. Med.
PUBLISHED: 02-10-2014
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Recruitment of circulating leukocytes into inflamed tissues depends on adhesion molecules expressed by endothelial cells (ECs). Here we report that rapamycin pretreatment reduced the ability of TNF-treated ECs to capture T cells under conditions of venular flow. This functional change was caused by inhibition of TNF-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and could be mimicked by knockdown of mammalian target of rapamycin (mTOR) or rictor, but not raptor, implicating mTORC2 as the target of rapamycin for this effect. Mechanistically, mTORC2 acts through Akt to repress Raf1-MEK1/2-ERK1/2 signaling, and inhibition of mTORC2 consequently results in hyperactivation of ERK1/2. Increased ERK1/2 activity antagonizes VCAM-1 expression by repressing TNF induction of the transcription factor IRF-1. Preventing activation of ERK1/2 reduced the ability of rapamycin to inhibit TNF-induced VCAM-1 expression. In vivo, rapamycin inhibited mTORC2 activity and potentiated activation of ERK1/2. These changes correlated with reduced endothelial expression of TNF-induced VCAM-1, which was restored via pharmacological inhibition of ERK1/2. Functionally, rapamycin reduced infiltration of leukocytes into renal glomeruli, an effect which was partially reversed by inhibition of ERK1/2. These data demonstrate a novel mechanism by which rapamycin modulates the ability of vascular endothelium to mediate inflammation and identifies endothelial mTORC2 as a potential therapeutic target.
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Tgfbr2 disruption in postnatal smooth muscle impairs aortic wall homeostasis.
J. Clin. Invest.
PUBLISHED: 01-09-2014
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TGF-? is essential for vascular development; however, excess TGF-? signaling promotes thoracic aortic aneurysm and dissection in multiple disorders, including Marfan syndrome. Since the pathology of TGF-? overactivity manifests primarily within the arterial media, it is widely assumed that suppression of TGF-? signaling in vascular smooth muscle cells will ameliorate aortic disease. We tested this hypothesis by conditional inactivation of Tgfbr2, which encodes the TGF-? type II receptor, in smooth muscle cells of postweanling mice. Surprisingly, the thoracic aorta rapidly thickened, dilated, and dissected in these animals. Tgfbr2 disruption predictably decreased canonical Smad signaling, but unexpectedly increased MAPK signaling. Type II receptor-independent effects of TGF-? and pathological responses by nonrecombined smooth muscle cells were excluded by serologic neutralization. Aortic disease was caused by a perturbed contractile apparatus in medial cells and growth factor production by adventitial cells, both of which resulted in maladaptive paracrine interactions between the vessel wall compartments. Treatment with rapamycin restored a quiescent smooth muscle phenotype and prevented dissection. Tgfbr2 disruption in smooth muscle cells also accelerated aneurysm growth in a murine model of Marfan syndrome. Our data indicate that basal TGF-? signaling in smooth muscle promotes postnatal aortic wall homeostasis and impedes disease progression.
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Ten-eleven translocation-2 (TET2) is a master regulator of smooth muscle cell plasticity.
Circulation
PUBLISHED: 09-27-2013
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Smooth muscle cells (SMCs) are remarkably plastic. Their reversible differentiation is required for growth and wound healing but also contributes to pathologies such as atherosclerosis and restenosis. Although key regulators of the SMC phenotype, including myocardin (MYOCD) and KLF4, have been identified, a unifying epigenetic mechanism that confers reversible SMC differentiation has not been reported.
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Alloantibody and Complement Promote T Cell-Mediated Cardiac Allograft Vasculopathy Through Noncanonical Nuclear Factor-?B Signaling in Endothelial Cells.
Circulation
PUBLISHED: 09-17-2013
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Cardiac allograft vasculopathy is the major cause of late allograft loss after heart transplantation. Cardiac allograft vasculopathy lesions contain alloreactive T cells that secrete interferon-?, a vasculopathic cytokine, and occur more frequently in patients with donor-specific antibody. Pathological interactions between these immune effectors, representing cellular and humoral immunity, respectively, remain largely unexplored.
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TNF, acting through inducibly expressed TNFR2, drives activation and cell cycle entry of c-Kit+ cardiac stem cells in ischemic heart disease.
Stem Cells
PUBLISHED: 04-15-2013
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TNF, signaling through TNFR2, has been implicated in tissue repair, a process that in the heart may be mediated by activated resident cardiac stem cells (CSCs). The objective of our study is to determine whether ligation of TNFR2 can induce activation of resident CSCs in the setting of ischemic cardiac injury. We show that in human cardiac tissue affected by ischemia heart disease (IHD), TNFR2 is expressed on intrinsic CSCs, identified as c-kit(+)/CD45(-)/VEGFR2(-) interstitial round cells, which are activated as determined by entry to cell cycle and expression of Lin-28. Wild-type mouse heart organ cultures subjected to hypoxic conditions both increase cardiac TNF expression and show induced TNFR2 and Lin-28 expression in c-kit(+) CSCs that have entered cell cycle. These CSC responses are enhanced by exogenous TNF. TNFR2(-/-) mouse heart organ cultures subjected to hypoxia increase cardiac TNF but fail to induce CSC activation. Similarly, c-kit(+) CSCs isolated from mouse hearts exposed to hypoxia or TNF show induction of Lin-28, TNFR2, cell cycle entry, and cardiogenic marker, ?-sarcomeric actin (?-SA), responses more pronounced by hypoxia in combination with TNF. Knockdown of Lin-28 by siRNA results in reduced levels of TNFR2 expression, cell cycle entry, and diminished expression of ?-SA. We conclude that hypoxia-induced c-kit(+) CSC activation is mediated by TNF/TNFR2/Lin-28 signaling. These observations suggest that TNFR2 signaling in resident c-kit(+) CSCs induces cardiac repair, findings which provide further understanding of the unanticipated harmful effects of TNF blockade in human IHD.
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SOCS1 Prevents Graft Arteriosclerosis by Preserving Endothelial Cell Function.
J. Am. Coll. Cardiol.
PUBLISHED: 04-11-2013
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The aim of this study was to determine the role of Suppressor of Cytokine Signaling 1 (SOCS1) in graft arteriosclerosis (GA).
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Rapamycin inhibits smooth muscle cell proliferation and obstructive arteriopathy attributable to elastin deficiency.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 03-14-2013
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Patients with elastin deficiency attributable to gene mutation (supravalvular aortic stenosis) or chromosomal microdeletion (Williams syndrome) are characterized by obstructive arteriopathy resulting from excessive smooth muscle cell (SMC) proliferation, mural expansion, and inadequate vessel size. We investigated whether rapamycin, an inhibitor of the cell growth regulator mammalian target of rapamycin (mTOR) and effective against other SMC proliferative disorders, is of therapeutic benefit in experimental models of elastin deficiency.
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Rapamycin-treated human endothelial cells preferentially activate allogeneic regulatory T cells.
J. Clin. Invest.
PUBLISHED: 01-17-2013
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Human graft endothelial cells (ECs) can act as antigen-presenting cells to initiate allograft rejection by host memory T cells. Rapamycin, an mTOR inhibitor used clinically to suppress T cell responses, also acts on DCs, rendering them tolerogenic. Here, we report the effects of rapamycin on EC alloimmunogenicity. Compared with mock-treated cells, rapamycin-pretreated human ECs (rapa-ECs) stimulated less proliferation and cytokine secretion from allogeneic CD4+ memory cells, an effect mimicked by shRNA knockdown of mTOR or raptor in ECs. The effects of rapamycin persisted for several days and were linked to upregulation of the inhibitory molecules PD-L1 and PD-L2 on rapa-ECs. Additionally, rapa-ECs produced lower levels of the inflammatory cytokine IL-6. CD4+ memory cells activated by allogeneic rapa-ECs became hyporesponsive to restimulation in an alloantigen-specific manner and contained higher percentages of suppressive CD4+CD25(hi)CD127(lo)FoxP3+ cells that did not produce effector cytokines. In a human-mouse chimeric model of allograft rejection, rapamycin pretreatment of human arterial allografts increased graft EC expression of PD-L1 and PD-L2 and reduced subsequent infiltration of allogeneic effector T cells into the artery intima and intimal expansion. Preoperative conditioning of allograft ECs with rapamycin could potentially reduce immune-mediated rejection.
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The effect of a lung cancer care coordination program on timeliness of care.
Clin Lung Cancer
PUBLISHED: 01-13-2013
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Timeliness of care improves patient satisfaction and might improve outcomes. The CCCP was established in November 2007 to improve timeliness of care of NSCLC at the Veterans Affairs Connecticut Healthcare System (VACHS).
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Claudin-5 controls intercellular barriers of human dermal microvascular but not human umbilical vein endothelial cells.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 01-03-2013
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To assess the role claudin-5, an endothelial cell (EC) tight junction protein, plays in establishing basal permeability levels in humans by comparing claudin-5 expression levels in situ and analyzing junctional organization and function in 2 widely used models of cultured ECs, namely human dermal microvascular (HDM)ECs and human umbilical vein (HUV)ECs.
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The Nogo-B-PirB Axis Controls Macrophage-Mediated Vascular Remodeling.
PLoS ONE
PUBLISHED: 01-01-2013
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Nogo-B mediates vascular protection and facilitates monocyte- and macrophage-dependent vascular remodeling. PirB is an alternate receptor for Nogo-B, but a role for the Nogo-PirB axis within the vascular system has not been previously reported. We examined whether Nogo-B or PirB play a role in regulating macrophage-mediated vascular remodeling and hypothesized that endothelial Nogo-B regulates vein graft macrophage infiltration via its alternate receptor PirB.
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IDO and regulatory T cell support are critical for cytotoxic T lymphocyte-associated Ag-4 Ig-mediated long-term solid organ allograft survival.
J. Immunol.
PUBLISHED: 11-30-2011
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Costimulatory blockade of CD28-B7 interaction with CTLA4Ig is a well-established strategy to induce transplantation tolerance. Although previous in vitro studies suggest that CTLA4Ig upregulates expression of the immunoregulatory enzyme IDO in dendritic cells, the relationship of CTLA4Ig and IDO in in vivo organ transplantation remains unclear. In this study, we studied whether concerted immunomodulation in vivo by CTLA4Ig depends on IDO. C57BL/6 recipients receiving a fully MHC-mismatched BALB/c heart graft treated with CTLA4Ig + donor-specific transfusion showed indefinite graft survival (>100 d) without signs of chronic rejection or donor specific Ab formation. Recipients with long-term surviving grafts had significantly higher systemic IDO activity as compared with rejectors, which markedly correlated with intragraft IDO and Foxp3 levels. IDO inhibition with 1-methyl-dl-tryptophan, either at transplant or at postoperative day 50, abrogated CTLA4Ig + DST-induced long-term graft survival. Importantly, IDO1 knockout recipients experienced acute rejection and graft survival comparable to controls. In addition, ?CD25 mAb-mediated depletion of regulatory T cells (Tregs) resulted in decreased IDO activity and again prevented CTLA4Ig + DST induced indefinite graft survival. Our results suggest that CTLA4Ig-induced tolerance to murine cardiac allografts is critically dependent on synergistic cross-linked interplay of IDO and Tregs. These results have important implications for the clinical development of this costimulatory blocker.
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Inhibition of microRNA-29 enhances elastin levels in cells haploinsufficient for elastin and in bioengineered vessels--brief report.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 11-17-2011
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The goal of this study was to determine whether antagonizing microRNA (miR)-29 enhances elastin (ELN) levels in cells and tissues lacking ELN.
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Neutralizing IL-6 reduces human arterial allograft rejection by allowing emergence of CD161+ CD4+ regulatory T cells.
J. Immunol.
PUBLISHED: 11-14-2011
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Perioperative injuries to an allograft exacerbate graft rejection, which in humans is primarily mediated by effector memory T cells. IL-6 transcripts in human coronary artery segments rapidly increase posttransplantation into immunodeficient mouse hosts compared with those of pretransplant specimens and fall dramatically by 30 d. Adoptive transfer of human PBMCs allogeneic to the artery 2 d postoperatively results in T cell infiltrates and intimal expansion 4 wk later. Ab neutralization of human IL-6 reduces the magnitude of intimal expansion and total T cell infiltration but increases the relative expression of CD161 while decreasing other Th17 markers. Coculture of MHC class II-expressing human endothelial cells (ECs) with allogeneic CD4(+) memory T cells results in T cell activation and EC secretion of IL-6. Neutralizing IL-6 in primary allogeneic T cell-EC cocultures results in enhanced T cell proliferation of CD161(+) CD4(+) T cells, reduces total T cell proliferation upon restimulation in secondary cultures (an effect dependent on CD161(+) T cells), increases expression of FOXP3 in CD161(+) T cells, and generates T cells that suppress proliferation of freshly isolated T cells. These data suggest that IL-6 released from injured allograft vessels enhances allogeneic T cell infiltration and intimal expansion in a model of human allograft rejection by inhibiting an increase in CD161(+) regulatory T cells.
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Reperfusion injury intensifies the adaptive human T cell alloresponse in a human-mouse chimeric artery model.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 11-03-2011
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Perioperative nonimmune injuries to an allograft can decrease graft survival. We have developed a model for studying this process using human materials.
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Participation of blood vessel cells in human adaptive immune responses.
Trends Immunol.
PUBLISHED: 08-09-2011
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Circulating T cells contact blood vessels either when they extravasate across the walls of microvessels into inflamed tissues or when they enter into the walls of larger vessels in inflammatory diseases such as atherosclerosis. The blood vessel wall is largely composed of three cell types: endothelial cells lining the entire vascular tree; pericytes supporting the endothelium of microvessels; and smooth muscle cells forming the bulk of large vessel walls. Each of these cell types interacts with and alters the behavior of infiltrating T cells in different ways, making these cells active participants in the processes of immune-mediated inflammation. In this review, we compare and contrast what is known about the nature of these interactions in humans.
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AIP1 prevents graft arteriosclerosis by inhibiting interferon-?-dependent smooth muscle cell proliferation and intimal expansion.
Circ. Res.
PUBLISHED: 06-23-2011
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ASK1-interacting protein-1 (AIP1), a Ras GTPase-activating protein family member, is highly expressed in endothelial cells and vascular smooth musccells (VSMCs). The role of AIP1 in VSMCs and VSMC proliferative disease is not known.
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Peroxisome proliferator-activated receptor-? agonists prevent in vivo remodeling of human artery induced by alloreactive T cells.
Circulation
PUBLISHED: 06-20-2011
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Ligands activating the transcription factor peroxisome proliferator-activated receptor-? (PPAR?) have antiinflammatory effects. Vascular rejection induced by allogeneic T cells can be responsible for acute and chronic graft loss. Studies in rodents suggest that PPAR? agonists may inhibit graft vascular rejection, but human T-cell responses to allogeneic vascular cells differ from those in rodents, and the effects of PPAR? in human transplantation are unknown.
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Circulating interferon-?-inducible Cys-X-Cys chemokine receptor 3 ligands are elevated in humans with aortic aneurysms and Cys-X-Cys chemokine receptor 3 is necessary for aneurysm formation in mice.
J. Thorac. Cardiovasc. Surg.
PUBLISHED: 04-16-2011
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Inflammation is associated with the formation of aortic aneurysm. This study investigates the role of inducible Cys-X-Cys chemokine receptor 3 and its ligands in the pathogenesis of arterial aneurysms.
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Vascular smooth muscle cell-derived adiponectin: a paracrine regulator of contractile phenotype.
J. Mol. Cell. Cardiol.
PUBLISHED: 04-07-2011
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Adiponectin is a cardioprotective adipokine derived predominantly from visceral fat. We recently demonstrated that exogenous adiponectin induces vascular smooth muscle cell (VSMC) differentiation via repression of mTORC1 and FoxO4. Here we report for the first time that VSMC express and secrete adiponectin, which acts in an autocrine and paracrine manner to regulate VSMC contractile phenotype. Adiponectin was found to be expressed in human coronary artery and mouse aortic VSMC. Importantly, siRNA knock-down of endogenous adiponectin in VSMC significantly reduced the expression of VSMC contractile proteins. Contractile protein deficiency was also observed in primary VSMC isolated from Adiponectin(-/-) mice. This deficiency could be rescued by culturing Adiponectin(-/-) VSMC in conditioned media from wild type (WT) VSMC. Moreover, the paracrine effect of VSMC-derived adiponectin was confirmed as adiponectin neutralizing antibody blocked the rescue. Overexpressed adiponectin also exerted paracrine effects on neighboring untransfected VSMC, which was also blocked by adiponectin neutralizing antibody. Interestingly, adiponectin expression was inducible by the PPAR? agonist rosiglitazone. Our data support an important role for VSMC-derived adiponectin in maintaining VSMC contractile phenotype, contributing to critical cardioprotective functions in the vascular wall. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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Activation of human vascular cells decreases their expression of transforming growth factor-beta.
Atherosclerosis
PUBLISHED: 04-04-2011
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Despite pro-fibrotic effects, transforming growth factor (TGF)-? prevents arteriosclerosis by suppressing effector leukocytes and promoting smooth muscle differentiation. However, previous observations of increased TGF-? expression in arteriosclerotic plaques are not consistent with that of an effective protective factor. We investigated the expression, regulation, and responses of TGF-? in human arterial tissues and cells.
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Wild-type LRP6 inhibits, whereas atherosclerosis-linked LRP6R611C increases PDGF-dependent vascular smooth muscle cell proliferation.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 01-18-2011
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Vascular smooth muscle cell (VSMC) proliferation is an important event in atherosclerosis and other vasculopathies. PDGF signaling is a key mediator of SMC proliferation, but the mechanisms that control its activity remain unclear. We previously identified a mutation in LDL receptor-related protein 6 (LRP6), LRP6(R611C), that causes early atherosclerosis. Examination of human atherosclerotic coronary arteries showed markedly increased expression of LRP6 and colocalization with PDGF receptor ? (PDGFR-?). Further investigation showed that wild-type LRP6 inhibits but LRP6(R611C) promotes VSMC proliferation in response to PDGF. We found that wild-type LRP6 forms a complex with PDGFR-? and enhances its lysosomal degradation, functions that are severely impaired in LRP6(R611C). Further, we observed that wild-type and mutant LRP6 regulate cell-cycle activity by triggering differential effects on PDGF-dependent pathways. These findings implicate LRP6 as a critical modulator of PDGF-dependent regulation of cell cycle in smooth muscle and indicate that loss of this function contributes to development of early atherosclerosis in humans.
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CXCR3-dependent accumulation and activation of perivascular macrophages is necessary for homeostatic arterial remodeling to hemodynamic stresses.
J. Exp. Med.
PUBLISHED: 08-23-2010
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Sustained changes in blood flow modulate the size of conduit arteries through structural alterations of the vessel wall that are dependent on the transient accumulation and activation of perivascular macrophages. The leukocytic infiltrate appears to be confined to the adventitia, is responsible for medial remodeling, and resolves once hemodynamic stresses have normalized without obvious intimal changes. We report that inward remodeling of the mouse common carotid artery after ligation of the ipsilateral external carotid artery is dependent on the chemokine receptor CXCR3. Wild-type myeloid cells restored flow-mediated vascular remodeling in CXCR3-deficient recipients, adventitia-infiltrating macrophages of Gr1(low) resident phenotype expressed CXCR3, the perivascular accumulation of macrophages was dependent on CXCR3 signaling, and the CXCR3 ligand IP-10 was sufficient to recruit monocytes to the adventitia. CXCR3 also contributed to selective features of macrophage activation required for extracellular matrix turnover, such as production of the transglutaminase factor XIII A subunit. Human adventitial macrophages displaying a CD14(+)/CD16(+) resident phenotype, but not circulating monocytes, expressed CXCR3, and such cells were more frequent at sites of disturbed flow. Our observations reveal a CXCR3-dependent accumulation and activation of perivascular macrophages as a necessary step in homeostatic arterial remodeling triggered by hemodynamic stress in mice and possibly in humans as well.
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IFN-gamma primes intact human coronary arteries and cultured coronary smooth muscle cells to double-stranded RNA- and self-RNA-induced inflammatory responses by upregulating TLR3 and melanoma differentiation-associated gene 5.
J. Immunol.
PUBLISHED: 06-18-2010
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Atherosclerosis of native coronary arteries and graft arteriosclerosis in transplanted hearts are characterized by activation of innate and adaptive immune responses. Nucleic acids generated by infections or cell death have been detected within arteriosclerotic lesions, and it is known that microbial and synthetic nucleic acids evoke inflammatory responses in cultured vascular cells. In this study, we report that model RNA, but not DNA, instigated robust cytokine and chemokine production from intact human coronary arteries containing both intrinsic vascular cells and resident/infiltrating leukocytes. An ssRNA analog induced TNF-alpha and IFN-gamma-induced protein of 10 kDa secretion by isolated human PBMCs, but not vascular cells. Conversely, synthetic dsRNA induced these inflammatory mediators by vascular cells, but not PBMCs. IFN-gamma, a cytokine linked to atherosclerosis and graft arteriosclerosis, potentiated the inflammatory responses of intact arteries and cultured vascular smooth muscle cells (VSMCs) to polyinosinic:polycytidylic acid [poly(I:C)] and was necessary for inflammatory responses of VSMC to self-RNA derived from autologous cells. IFN-gamma also induced the expression of TLR3, melanoma differentiation-associated gene 5, and retinoic acid-inducible gene I dsRNA receptors. Small interfering RNA knockdown revealed that TLR3 mediated VSMC activation by poly(I:C), whereas melanoma differentiation-associated gene 5 was more important for VSMC stimulation by self-RNA. IFN-gamma-mediated induction of dsRNA receptors and priming for inflammatory responses to poly(I:C) was confirmed in vivo using immunodeficient mice bearing human coronary artery grafts. These findings suggest that IFN-gamma, and by inference adaptive immunity, sensitizes the vasculature to innate immune activators, such as RNA, and activation of IFN-gamma-primed vascular cells by exogenous or endogenous sources of RNA may contribute to the inflammatory milieu of arteriosclerosis.
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Human vascular smooth muscle cells lack essential costimulatory molecules to activate allogeneic memory T cells.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 06-10-2010
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The arterial media, populated by vascular smooth muscle cells (VSMC), is an immunoprivileged compartment and, in contrast to the intima or adventitia containing endothelial cells, is generally spared by inflammatory processes, such as arteriosclerosis. To determine mechanisms of medial immunoprivilege, we investigated the ability of human VSMC versus endothelial cells to activate allogeneic T cells in vitro.
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VEGF blockade inhibits lymphocyte recruitment and ameliorates immune-mediated vascular remodeling.
Circ. Res.
PUBLISHED: 06-10-2010
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There are conflicting data on the effects of vascular endothelial growth factor (VEGF) in vascular remodeling. Furthermore, there are species-specific differences in leukocyte and vascular cell biology and little is known about the role of VEGF in remodeling of human arteries.
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Human aortic smooth muscle cells promote arteriole formation by coengrafted endothelial cells.
Tissue Eng Part A
PUBLISHED: 04-21-2009
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Collagen-fibronectin gels containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVEC) implanted in the abdominal walls of immunodeficient mice form mature microvessels invested by host-derived smooth muscle cells (SMC) by 8 weeks. We tested the hypothesis that coengraftment of human aortic SMC (HASMC) could accelerate vessel maturation. To prevent SMC-mediated gel contraction, we polymerized the gel within a nonwoven poly(glycolic acid) (PGA) scaffold. Implanted grafts were evaluated at 15, 30, and 60 days. Acellular PGA-supported protein gels elicited a macrophage-rich foreign body reaction and transient host angiogenic response. When transplanted alone, HASMC tightly associated with the fibers of the scaffold and incorporated into the walls of angiogenic mouse microvessels, preventing their regression. When transplanted alone in PGA-supported gels, Bcl-2-HUVEC retained the ability to form microvessels invested by mouse SMC. Interestingly, grafts containing both Bcl-2-HUVEC and HASMC displayed greater numbers of smooth muscle alpha-actin-expressing cells associated with human EC-lined arteriole-like microvessels at all times examined and showed a significant increase in the number of larger caliber microvessels at 60 days. We conclude that SMC coengraftment can accelerate vessel development by EC and promote arteriolization. This strategy of EC-SMC coengraftment in PGA-supported protein gels may have broader application for perfusing bioengineered tissues.
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Interleukin-17 and interferon-gamma are produced concomitantly by human coronary artery-infiltrating T cells and act synergistically on vascular smooth muscle cells.
Circulation
PUBLISHED: 03-02-2009
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Atherosclerosis is an inflammatory disease in which interferon (IFN)-gamma, the signature cytokine of Th1 cells, plays a central role. We investigated whether interleukin (IL)-17, the signature cytokine of Th17 cells, is also associated with human coronary atherosclerosis.
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Development of a humanized mouse model to study the role of macrophages in allograft injury.
Transplantation
PUBLISHED: 01-22-2009
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Nearly half of all infiltrating leukocytes in rejecting human allografts are macrophages, yet, in comparison with T cells, much less is known about the contribution of this cell type to rejection. Our laboratory has previously described models of rejection of human skin or artery grafts in immunodeficient mouse hosts mediated by adoptively transferred allogeneic T cells. However, mature human monocyte/macrophages have consistently failed to engraft in these animals. Here, we describe the introduction of human CD68+ macrophages into irradiated immunodeficient mice by transplantation of enriched CD34+ hematopoietic stem-cells isolated from peripheral blood of G-colony-stimulating factor pretreated adults.
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FGF regulates TGF-? signaling and endothelial-to-mesenchymal transition via control of let-7 miRNA expression.
Cell Rep
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Maintenance of normal endothelial function is critical to various aspects of blood vessel function, but its regulation is poorly understood. In this study, we show that disruption of baseline fibroblast growth factor (FGF) signaling to the endothelium leads to a dramatic reduction in let-7 miRNA levels that, in turn, increases expression of transforming growth factor (TGF)-? ligands and receptors and activation of TGF-? signaling, leading to endothelial-to-mesenchymal transition (Endo-MT). We also find that Endo-MT is an important driver of neointima formation in a murine transplant arteriopathy model and in rejection of human transplant lesions. The decline in endothelial FGF signaling input is due to the appearance of an FGF resistance state that is characterized by inflammation-dependent reduction in expression and activation of key components of the FGF signaling cascade. These results establish FGF signaling as a critical factor in maintenance of endothelial homeostasis and point to an unexpected role of Endo-MT in vascular pathology.
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The effects of vitamin D repletion on endothelial function and inflammation in patients with coronary artery disease.
Vasc Med
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Adequate vitamin D levels may promote cardiovascular health by improving endothelial function and down-regulating inflammation. The objective of this pilot trial was to investigate the effects of vitamin D repletion on endothelial function and inflammation in patients with coronary artery disease (CAD). Using a double-blind placebo wait-list control design, 90 subjects with CAD and vitamin D deficiency (< 20 ng/ml) were randomized 1:1 to 50,000 IU of oral ergocalciferol or placebo weekly for 12 weeks. Endothelial function (reactive hyperemia peripheral arterial tonometry, RH-PAT), circulating adhesion molecules, and pro-inflammatory cytokines were measured at baseline and 12 weeks. The median increase in serum 25-vitamin D from baseline was 26 ± 17 ng/ml in the active group and 4 ± 8 ng/ml in the placebo group (between-group difference = 22 ng/ml, p < 0.001). The median within-subject change in RH-PAT score was 0.13 ± 0.73 with active treatment and -0.04 ± 0.63 with placebo (between-group difference = 0.17, p = 0.44). Within-group and between-group differences in intercellular adhesion molecule levels were greater with placebo (between-group difference = 6 ng/ml, p = 0.048). Vascular cell adhesion molecule levels decreased in both groups by a similar magnitude (median difference between groups = 8.5 ng/ml, p = 0.79). There was no difference between groups in magnitude of reduction in interleukin (IL)-12 (-8.6 ng/ml, p = 0.72) and interferon-gamma (0.52 ng/ml, p = 0.88). No significant differences in blood pressure, e-selectin, high-sensitivity c-reactive protein, IL-6 or the chemokine CXCL-10 were found with treatment. In conclusion, repleting vitamin D levels in subjects with CAD failed to demonstrate any benefits on surrogate markers of cardiovascular health. These results question the role of vitamin D supplementation in modifying cardiovascular disease.
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Modulation of transforming growth factor-? signaling and extracellular matrix production in myxomatous mitral valves by angiotensin II receptor blockers.
Circulation
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Little is known about the pathophysiology of myxomatous degeneration of the mitral valve, the pathological hallmark of mitral valve prolapse, associated with symptomatic mitral regurgitation, heart failure, and death. Excess transforming growth factor (TGF)-? signaling is known to cause mitral valve degeneration and regurgitation in a mouse model of Marfan syndrome. We examined if TGF-? signaling is dysregulated in clinical specimens of sporadic mitral valve prolapse compared with explanted nondiseased mitral valves and we tested the effects of angiotensin II receptor blockers on TGF-? signaling in cultured human mitral valve cells.
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Modeling supravalvular aortic stenosis syndrome with human induced pluripotent stem cells.
Circulation
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Supravalvular aortic stenosis (SVAS) is caused by mutations in the elastin (ELN) gene and is characterized by abnormal proliferation of vascular smooth muscle cells (SMCs) that can lead to narrowing or blockage of the ascending aorta and other arterial vessels. Having patient-specific SMCs available may facilitate the study of disease mechanisms and development of novel therapeutic interventions.
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Molecular imaging of vascular endothelial growth factor receptors in graft arteriosclerosis.
Arterioscler. Thromb. Vasc. Biol.
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Vascular endothelial growth factor (VEGF) signaling plays a key role in the pathogenesis of vascular remodeling, including graft arteriosclerosis. Graft arteriosclerosis is the major cause of late organ failure in cardiac transplantation. We used molecular near-infrared fluorescent imaging with an engineered Cy5.5-labeled single-chain VEGF tracer (scVEGF/Cy) to detect VEGF receptors and vascular remodeling in human coronary artery grafts by molecular imaging.
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miR-1 mediated suppression of Sorcin regulates myocardial contractility through modulation of Ca2+ signaling.
J. Mol. Cell. Cardiol.
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MicroRNAs are negative gene regulators and play important roles in cardiac development and disease. As evident by cardiomyopathy following cardiac-specific Dicer knockdown they also are required for maintaining normal cardiac contractile function but the specific role of miR-1 in the process is poorly understood. To characterize the role of miR-1 in particular and to identify its specific targets we created a tamoxifen-inducible, cardiac-specific Dicer knockdown mouse and demonstrated that Dicer downregulation results in a dramatic and rapid decline in cardiac function concurrent with significantly reduced levels of miR-1. The importance of miR-1 was established by miR-1 antagomir treatment of wild-type mice, which replicated the cardiac-specific Dicer knockdown phenotype. Down-regulation of miR-1 was associated with up-regulation of its predicted target Sorcin, an established modulator of calcium signaling and excitation-contraction coupling, subsequently verified as a miR-1 target with luciferase constructs. siRNA-mediated knockdown of Sorcin effectively rescued the cardiac phenotypes after Dicer or miR-1 knockdown affirming Sorcin as a critical mediator of the acute cardiomyopathy observed. The regulatory relationship between miR-1 and Sorcin was further confirmed in cultured mouse cardiomyocytes where modulation of miR-1 was associated with discordant Sorcin levels and dysregulation of calcium signaling. Pathological relevance of our findings included decreased miR-1 and increased Sorcin expression in end-stage cardiomyopathy. These findings demonstrate the importance of miR-1 in cardiac function and in the pathogenesis of heart failure via Sorcin-dependent calcium homeostasis.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.