Publications by authors named "Paolo Mignatti"

38 Publications

Membrane-type 1 Matrix Metalloproteinase Modulates Tissue Homeostasis by a Non-proteolytic Mechanism.

iScience 2020 Dec 10;23(12):101789. Epub 2020 Nov 10.

Department of Medicine, Division of Rheumatology, NYU School of Medicine, 301 East 17th Street, Suite 1612A, NY 10003, USA.

Membrane-type 1 matrix metalloproteinase (MT1-MMP, MMP-14), a transmembrane proteinase with a short cytoplasmic tail, is a major effector of extracellular matrix remodeling. Genetic silencing of MT1-MMP in mouse ( ) and man causes dwarfism, osteopenia, arthritis, and lipodystrophy, abnormalities ascribed to defective collagen turnover. We have previously shown non-proteolytic functions of MT1-MMP mediated by its cytoplasmic tail, where the unique tyrosine (Y573) controls intracellular signaling. The Y573D mutation blocks TIMP-2/MT1-MMP-induced Erk1/2 and Akt signaling without affecting proteolytic activity. Here, we report that a mouse with the MT1-MMP Y573D mutation ( ) shows abnormalities similar to but also different from those of mice. Skeletal stem cells (SSC) of mice show defective differentiation consistent with the mouse phenotype, which is rescued by wild-type SSC transplant. These results provide the first demonstration that MT1-MMP modulates bone, cartilage, and fat homeostasis by controlling SSC differentiation through a mechanism independent of proteolysis.
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http://dx.doi.org/10.1016/j.isci.2020.101789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695985PMC
December 2020

Periostin interaction with discoidin domain receptor-1 (DDR1) promotes cartilage degeneration.

PLoS One 2020 24;15(4):e0231501. Epub 2020 Apr 24.

Division of Rheumatology, Department of Medicine, NYU Grossman School of Medicine, NYU Langone Orthopedic Hospital, New York, NY, United States of America.

Osteoarthritis (OA) is characterized by progressive loss of articular cartilage accompanied by the new bone formation and, often, a synovial proliferation that culminates in pain, loss of joint function, and disability. However, the cellular and molecular mechanisms of OA progression and the relative contributions of cartilage, bone, and synovium remain unclear. We recently found that the extracellular matrix (ECM) protein periostin (Postn, or osteoblast-specific factor, OSF-2) is expressed at high levels in human OA cartilage. Multiple groups have also reported elevated expression of Postn in several rodent models of OA. We have previously reported that in vitro Postn promotes collagen and proteoglycan degradation in human chondrocytes through AKT/β-catenin signaling and downstream activation of MMP-13 and ADAMTS4 expression. Here we show that Postn induces collagen and proteoglycan degradation in cartilage by signaling through discoidin domain receptor-1 (DDR1), a receptor tyrosine kinase. The genetic deficiency or pharmacological inhibition of DDR1 in mouse chondrocytes blocks Postn-induced MMP-13 expression. These data show that Postn is signaling though DDR1 is mechanistically involved in OA pathophysiology. Specific inhibitors of DDR1 may provide therapeutic opportunities to treat OA.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231501PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7182230PMC
July 2020

Matrix Metalloproteinase Inhibitors in Cancer Therapy: Turning Past Failures Into Future Successes.

Mol Cancer Ther 2018 06 7;17(6):1147-1155. Epub 2018 May 7.

New York University School of Medicine, Department of Medicine and Perlmutter Cancer Center, New York, New York.

The matrix metalloproteinases (MMP) are a family of proteolytic enzymes that degrade multiple components of the extracellular matrix. A large body of experimental and clinical evidence has implicated MMPs in tumor invasion, neoangiogenesis, and metastasis, and therefore they represent ideal pharmacologic targets for cancer therapy. From the 1990s to early 2000s, synthetic inhibitors of MMPs (MMPI) were studied in various cancer types. Unexpectedly, despite strongly promising preclinical data, all trials were unsuccessful in reducing tumor burden or improving overall survival; in addition, MMPIs had unforeseen, severe side effects. Two main reasons can explain the failure of MMPIs in clinical trials. It has now become apparent that some MMPs have antitumor effects; therefore, the broad-spectrum MMPIs used in the initial trials might block these MMPs and result in tumor progression. In addition, although MMPs are involved in the early stages of tumor progression, MMPIs were tested in patients with advanced disease, beyond the stage when these compounds could be effective. As more specific MMPIs are now available, MMP targeting could be reconsidered for cancer therapy; however, new trials should be designed to test their antimetastatic properties in early-stage tumors, and endpoints should focus on parameters other than decreasing metastatic tumor burden. .
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http://dx.doi.org/10.1158/1535-7163.MCT-17-0646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5984693PMC
June 2018

Arrested Development: Infantile Hemangioma and the Stem Cell Teratogenic Hypothesis.

Lymphat Res Biol 2017 06 18;15(2):153-165. Epub 2017 May 18.

4 Department of Medicine, New York University School of Medicine , New York, New York.

Background: Early-life programming is defined by the adaptive changes made by the fetus in response to an adverse in utero environment. Infantile hemangioma (IH), a vascular anomaly, is the most common tumor of infancy. Here we take IH as the tumor model to propose the stem cell teratogenic hypothesis of tumorigenesis and the potential involvement of the immune system.

Objectives: Teratogenic agents include chemicals, heavy metals, pathogens, and ionizing radiation. To investigate the etiology and pathogenesis of IH, we hypothesized that they result from a teratogenic mechanism. Immature, incompletely differentiated, dysregulated progenitor cells (multipotential stem cells) are arrested in development with vasculogenic, angiogenic, and tumorigenic potential due to exposure to teratogenic agents such as extrinsic factors that disrupt intrinsic factors via molecular mimicry. During the critical period of immunological tolerance, environmental exposure to immunotoxic agents may harness the teratogenic potential in the developing embryo or fetus and modify the early-life programming algorithm by altering normal fetal development, causing malformations, and inducing tumorigenesis. Specifically, exposure to environmental agents may interfere with physiological signaling pathways and contribute to the generation of IH, by several mechanisms.

Discussion: An adverse in utero environment no longer serves as a sustainable environment for proper embryogenesis and normal development. Targeted disruption of stem cells by extrinsic factors can alter the genetic program.

Conclusions: This article offers new perspectives to stimulate discussion, explore novel experimental approaches (such as immunotoxicity/vasculotoxicity assays and novel isogenic models), and to address the questions raised to convert the hypotheses into nontoxic, noninvasive treatments.
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http://dx.doi.org/10.1089/lrb.2016.0030DOI Listing
June 2017

Infantile Hemangioma Originates From A Dysregulated But Not Fully Transformed Multipotent Stem Cell.

Sci Rep 2016 10 27;6:35811. Epub 2016 Oct 27.

Department of Medicine, New York University School of Medicine, 550 First Avenue New York, NY 10016, USA.

Infantile hemangioma (IH) is the most common tumor of infancy. Its cellular origin and biological signals for uncontrolled growth are poorly understood, and specific pharmacological treatment is unavailable. To understand the process of hemangioma-genesis we characterized the progenitor hemangioma-derived stem cell (HemSC) and its lineage and non-lineage derivatives. For this purpose we performed a high-throughput (HT) phenotypic and gene expression analysis of HemSCs, and analyzed HemSC-derived tumorspheres. We found that IH is characterized by high expression of genes involved in vasculogenesis, angiogenesis, tumorigenesis and associated signaling pathways. These results show that IH derives from a dysregulated stem cell that remains in an immature, arrested stage of development. The potential biomarkers we identified can afford the development of diagnostic tools and precision-medicine therapies to "rewire" or redirect cellular transitions at an early stage, such as signaling pathways or immune response modifiers.
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http://dx.doi.org/10.1038/srep35811DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081534PMC
October 2016

Inhibition of Breast Cancer Metastasis by Presurgical Treatment with an Oral Matrix Metalloproteinase Inhibitor: A Preclinical Proof-of-Principle Study.

Mol Cancer Ther 2016 10 27;15(10):2370-2377. Epub 2016 Jul 27.

Department of Medicine, New York University School of Medicine, New York, New York. Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, New York. Department of Cell Biology, New York University School of Medicine, New York, New York.

Breast cancer has the second highest death toll in women worldwide, despite significant progress in early diagnosis and treatments. The main cause of death is metastatic disease. Matrix metalloproteinases (MMP) are required for the initial steps of metastasis, and have therefore been considered as ideal pharmacologic targets for antimetastatic therapy. However, clinical trials of MMP inhibitors were unsuccessful. These trials were conducted in patients with advanced disease, beyond the stage when these compounds could have been effective. We hypothesized that early treatment with a selective MMP inhibitor between the time of diagnosis and definitive surgery, the so-called "window-of-opportunity," can inhibit metastasis and thereby improve survival. To investigate our hypothesis, we used the 4T1 mouse model of aggressive mammary carcinoma. We treated the animals with SD-7300, an oral inhibitor of MMP-2, -9, and -13, starting after the initial detection of the primary tumor. Seven days later, the primary tumors were excised and analyzed for MMP activity, and the SD-7300 treatment was discontinued. After 4 weeks, the animals were sacrificed and their lungs analyzed histologically for number of metastases and metastatic burden (metastases' area/lung section area). SD-7300 treatment inhibited 70% to 80% of tumor-associated MMP activity (P = 0.0003), reduced metastasis number and metastatic burden by 50% to 60% (P = 0.002 and P = 0.0082, respectively), and increased survival (92% vs. 66.7%; P = 0.0409), relative to control vehicle. These results show that treatment of early invasive breast cancer with selective MMP inhibitors can lower the risk of recurrence and increase long-term disease-free survival. Mol Cancer Ther; 15(10); 2370-7. ©2016 AACR.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5050118PMC
http://dx.doi.org/10.1158/1535-7163.MCT-16-0194DOI Listing
October 2016

Mitral valve prolapse is associated with altered extracellular matrix gene expression patterns.

Gene 2016 Jul 6;586(1):56-61. Epub 2016 Apr 6.

Department of Cardiothoracic Surgery, NYU Langone Medical Center, New York, NY, United States. Electronic address:

Mitral valve prolapse (MVP) is the leading indication for isolated mitral valve surgery in the United States. Disorganization of collagens and glycosaminoglycans in the valvular extracellular matrix (ECM) are histological hallmarks of MVP. We performed a transcriptome analysis to study the alterations in ECM-related gene expression in humans with sporadic MVP. Mitral valve specimens were obtained from individuals undergoing valve repair for MVP (n=7 patients) and from non-beating heart-tissue donors (n=3 controls). Purified RNA was subjected to whole-transcriptome microarray analysis. Microarray results were validated by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Gene ontology enrichment analysis was performed. 2046 unique genes showed significant differential expression (false discovery rate <0.5%). After demonstrating appropriate sample clustering, microarray results were globally validated using a subset of 22 differentially expressed genes by RT-qPCR (Pearson's correlation r=0.65, p=0.001). Gene ontology enrichment analyses performed with ErmineJ and DAVID Bioinformatics Database demonstrated overrepresentation of ECM components (p<0.05). Functional annotation clustering calculated enrichment of ECM-related ontology groups (enrichment score=4.1). ECM-related gene expression is significantly altered in MVP. Our study is consistent with the histologically observed alterations in collagen and mucopolysaccharide profiles of myxomatous mitral valves. Furthermore, whole-transcriptome analyses suggest dysregulation of multiple pathways, including TGF-beta signaling.
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http://dx.doi.org/10.1016/j.gene.2016.04.004DOI Listing
July 2016

Urokinase Receptor Promotes Skin Tumor Formation by Preventing Epithelial Cell Activation of Notch1.

Cancer Res 2015 Nov 2;75(22):4895-909. Epub 2015 Nov 2.

Humanitas Clinical and Research Center, Rozzano, Milan, Italy. Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy.

The urokinase-type plasminogen activator receptor (uPAR) has a well-established role in cancer progression, but it has been little studied at earlier stages of cancer initiation. Here, we show that uPAR deficiency in the mouse dramatically reduces susceptibility to the classical two-stage protocol of inflammatory skin carcinogenesis. uPAR genetic deficiency decreased papilloma formation and accelerated keratinocyte differentiation, effects mediated by Notch1 hyperactivation. Notably, Notch1 inhibition in uPAR-deficient mice rescued their susceptibility to skin carcinogenesis. Clinically, we found that human differentiated keratoacanthomas expressed low levels of uPAR and high levels of activated Notch1, with opposite effects in proliferating tumors, confirming the relevance of the observations in mice. Furthermore, we found that TACE-dependent activation of Notch1 in basal kerantinocytes was modulated by uPAR. Mechanistically, uPAR sequestered TACE within lipid rafts to prevent Notch1 activation, thereby promoting cell proliferation and tumor formation. Given that uPAR signaling is nonessential for normal epidermal homeostasis, our results argue that uPAR may present a promising disease-specific target for preventing skin cancer development.
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http://dx.doi.org/10.1158/0008-5472.CAN-15-0378DOI Listing
November 2015

TIMP-2 Interaction with MT1-MMP Activates the AKT Pathway and Protects Tumor Cells from Apoptosis.

PLoS One 2015 2;10(9):e0136797. Epub 2015 Sep 2.

Department of Medicine, New York University School of Medicine, New York, New York, United States of America; Department of Cell Biology, New York University School of Medicine, New York University School of Medicine, New York, New York, United States of America.

Membrane-type 1 matrix metalloproteinase (MT1-MMP), a transmembrane proteinase with an extracellular catalytic domain and a short cytoplasmic tail, degrades a variety of extracellular matrix (ECM) components. In addition, MT1-MMP activates intracellular signaling through proteolysis-dependent and independent mechanisms. We have previously shown that binding of tissue inhibitor of metalloproteinases-2 (TIMP-2) to MT1-MMP controls cell proliferation and migration, as well as tumor growth in vivo by activating the Ras-extracellular signal regulated kinase-1 and -2 (ERK1/2) pathway through a mechanism that requires the cytoplasmic but not the proteolytic domain of MT1-MMP. Here we show that in MT1-MMP expressing cells TIMP-2 also induces rapid and sustained activation of AKT in a dose- and time-dependent manner and by a mechanism independent of the proteolytic activity of MT1-MMP. Fibroblast growth factor receptor-1 mediates TIMP-2 induction of ERK1/2 but not of AKT activation; however, Ras activation is necessary to transduce the TIMP-2-activated signal to both the ERK1/2 and AKT pathways. ERK1/2 and AKT activation by TIMP-2 binding to MT1-MMP protects tumor cells from apoptosis induced by serum starvation. Conversely, TIMP-2 upregulates apoptosis induced by three-dimensional type I collagen in epithelial cancer cells. Thus, TIMP-2 interaction with MT1-MMP provides tumor cells with either pro- or anti-apoptotic signaling depending on the extracellular environment and apoptotic stimulus.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136797PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4558019PMC
May 2016

Elevated expression of periostin in human osteoarthritic cartilage and its potential role in matrix degradation via matrix metalloproteinase-13.

FASEB J 2015 Oct 19;29(10):4107-21. Epub 2015 Jun 19.

*Division of Rheumatology, Department of Medicine, Department of Cell Biology, and Department of Orthopaedic Surgery, New York University (NYU) School of Medicine and NYU Langone Medical Center, New York, New York, USA; Frontier Research Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan; Department of Orthopaedics and Rehabilitation, University of Florida, Gainesville, Florida, USA; and Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.

We investigated the role of periostin, an extracellular matrix protein, in the pathophysiology of osteoarthritis (OA). In OA, dysregulated gene expression and phenotypic changes in articular chondrocytes culminate in progressive loss of cartilage from the joint surface. The molecular mechanisms underlying this process are poorly understood. We examined periostin expression by immunohistochemical analysis of lesional and nonlesional cartilage from human and rodent OA knee cartilage. In addition, we used small interfering (si)RNA and adenovirus transduction of chondrocytes to knock down and up-regulate periostin levels, respectively, and analyzed its effect on matrix metalloproteinase (MMP)-13, a disintegrin and MMP with thrombospondin motifs (ADAMTS)-4, and type II collagen expression. We found high periostin levels in human and rodent OA cartilage. Periostin increased MMP-13 expression dose [1-10 µg/ml (EC50 0.5-1 μg/ml)] and time (24-72 h) dependently, significantly enhanced expression of ADAMTS4 mRNA, and promoted cartilage degeneration through collagen and proteoglycan degradation. Periostin induction of MMP-13 expression was inhibited by CCT031374 hydrobromide, an inhibitor of the canonical Wnt/β-catenin signaling pathway. In addition, siRNA-mediated knockdown of endogenous periostin blocked constitutive MMP-13 expression. These findings implicate periostin as a catabolic protein that promotes cartilage degeneration in OA by up-regulating MMP-13 through canonical Wnt signaling.
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http://dx.doi.org/10.1096/fj.15-272427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566939PMC
October 2015

Membrane-Type 1 Matrix Metalloproteinase Downregulates Fibroblast Growth Factor-2 Binding to the Cell Surface and Intracellular Signaling.

J Cell Physiol 2015 Feb;230(2):366-77

Department of Cardiothoracic Surgery, New York University School of Medicine, New York.

Membrane-type 1 matrix metalloproteinase (MT1-MMP, MMP-14), a transmembrane proteinase with an extracellular catalytic domain and a short cytoplasmic tail, degrades extracellular matrix components and controls diverse cell functions through proteolytic and non-proteolytic interactions with extracellular, intracellular, and transmembrane proteins. Here we show that in tumor cells MT1-MMP downregulates fibroblast growth factor-2 (FGF-2) signaling by reducing the amount of FGF-2 bound to the cell surface with high and low affinity. FGF-2 induces weaker activation of ERK1/2 MAP kinase in MT1-MMP expressing cells than in cells devoid of MT1-MMP. This effect is abolished in cells that express proteolytically inactive MT1-MMP but persists in cells expressing MT1-MMP mutants devoid of hemopexin-like or cytoplasmic domain, showing that FGF-2 signaling is downregulated by MT1-MMP proteolytic activity. MT1-MMP expression results in downregulation of FGFR-1 and -4, and in decreased amount of cell surface-associated FGF-2. In addition, MT1-MMP strongly reduces the amount of FGF-2 bound to the cell surface with low affinity. Because FGF-2 association with low-affinity binding sites is a prerequisite for binding to its high-affinity receptors, downregulation of low-affinity binding to the cell surface results in decreased FGF-2 signaling. Consistent with this conclusion, FGF-2 induction of tumor cell migration and invasion in vitro is stronger in cells devoid of MT1- MMP than in MT1-MMP expressing cells. Thus, MT1-MMP controls FGF-2 signaling by a proteolytic mechanism that decreases the cell's biological response to FGF-2.
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http://dx.doi.org/10.1002/jcp.24717DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4281515PMC
February 2015

PKCε activation promotes FGF-2 exocytosis and induces endothelial cell proliferation and sprouting.

J Mol Cell Cardiol 2013 Oct 20;63:107-17. Epub 2013 Jul 20.

Department of Life Sciences, University of Siena, 53100 Siena, Italy.

Protein kinase C epsilon (PKCε) activation controls fibroblast growth factor-2 (FGF-2) angiogenic signaling. Here, we examined the effect of activating PKCε on FGF-2 dependent vascular growth and endothelial activation. ψεRACK, a selective PKCε agonist induces pro-angiogenic responses in endothelial cells, including formation of capillary like structures and cell growth. These effects are mediated by FGF-2 export to the cell membrane, as documented by biotinylation and immunofluorescence, and FGF-2/FGFR1 signaling activation, as attested by ERK1/2-STAT-3 phosphorylation and de novo FGF-2 synthesis. Similarly, vascular endothelial growth factor (VEGF) activates PKCε in endothelial cells, and promotes FGF-2 export and FGF-2/FGFR1 signaling activation. ψεRACK fails to elicit responses in FGF-2(-/-) endothelial cells, and in cells pretreated with methylamine (MeNH2), an exocytosis inhibitor, indicating that both intracellular FGF-2 and its export toward the membrane are required for the ψεRACK activity. In vivo ψεRACK does not induce angiogenesis in the rabbit cornea. However, ψεRACK promotes VEGF angiogenic responses, an effect sustained by endothelial FGF-2 release and synthesis, since anti-FGF-2 antibody strongly attenuates VEGF responses. The results demonstrate that PKCε stimulation promotes angiogenesis and modulates VEGF activity, by inducing FGF-2 release and autocrine signaling.
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http://dx.doi.org/10.1016/j.yjmcc.2013.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812807PMC
October 2013

TGF-β1 induces endothelial cell apoptosis by shifting VEGF activation of p38(MAPK) from the prosurvival p38β to proapoptotic p38α.

Mol Cancer Res 2012 May 20;10(5):605-14. Epub 2012 Apr 20.

Division of Cardiovascular Surgery, Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.

TGF-β1 and VEGF, both angiogenesis inducers, have opposing effects on vascular endothelial cells. TGF-β1 induces apoptosis; VEGF induces survival. We have previously shown that TGF-β1 induces endothelial cell expression of VEGF, which mediates TGF-β1 induction of apoptosis through activation of p38 mitogen-activated protein kinase (MAPK). Because VEGF activates p38(MAPK) but protects the cells from apoptosis, this finding suggested that TGF-β1 converts p38(MAPK) signaling from prosurvival to proapoptotic. Four isoforms of p38(MAPK) -α, β, γ, and δ-have been identified. Therefore, we hypothesized that different p38(MAPK) isoforms control endothelial cell apoptosis or survival, and that TGF-β1 directs VEGF activation of p38(MAPK) from a prosurvival to a proapoptotic isoform. Here, we report that cultured endothelial cells express p38α, β, and γ. VEGF activates p38β, whereas TGF-β1 activates p38α. TGF-β1 treatment rapidly induces p38α activation and apoptosis. Subsequently, p38α activation is downregulated, p38β is activated, and the surviving cells become refractory to TGF-β1 induction of apoptosis and proliferate. Gene silencing of p38α blocks TGF-β1 induction of apoptosis, whereas downregulation of p38β or p38γ expression results in massive apoptosis. Thus, in endothelial cells p38α mediates apoptotic signaling, whereas p38β and p38γ transduce survival signaling. TGF-β1 activation of p38α is mediated by VEGF, which in the absence of TGF-β1 activates p38β. Therefore, these results show that TGF-β1 induces endothelial cell apoptosis by shifting VEGF signaling from the prosurvival p38β to the proapoptotic p38α.
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http://dx.doi.org/10.1158/1541-7786.MCR-11-0507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356490PMC
May 2012

Protein targets of inflammatory serine proteases and cardiovascular disease.

J Inflamm (Lond) 2010 Aug 30;7:45. Epub 2010 Aug 30.

Department of Cardiothoracic Surgery, New York University School of Medicine, 530 First Avenue, New York, NY 10016, USA.

Serine proteases are a key component of the inflammatory response as they are discharged from activated leukocytes and mast cells or generated through the coagulation cascade. Their enzymatic activity plays a major role in the body's defense mechanisms but it has also an impact on vascular homeostasis and tissue remodeling. Here we focus on the biological role of serine proteases in the context of cardiovascular disease and their mechanism(s) of action in determining specific vascular and tissue phenotypes. Protease-activated receptors (PARs) mediate serine protease effects; however, these proteases also exert a number of biological activities independent of PARs as they target specific protein substrates implicated in vascular remodeling and the development of cardiovascular disease thus controlling their activities. In this review both PAR-dependent and -independent mechanisms of action of serine proteases are discussed for their relevance to vascular homeostasis and structural/functional alterations of the cardiovascular system. The elucidation of these mechanisms will lead to a better understanding of the molecular forces that control vascular and tissue homeostasis and to effective preventative and therapeutic approaches.
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http://dx.doi.org/10.1186/1476-9255-7-45DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936362PMC
August 2010

Correlation between plasma osteopontin levels and aortic valve calcification: potential insights into the pathogenesis of aortic valve calcification and stenosis.

J Thorac Cardiovasc Surg 2009 Jul 9;138(1):196-9. Epub 2009 Mar 9.

Department of Cardiothoracic Surgery, New York University Medical Center, New York, NY 10016, USA.

Objective: The inflammatory process of aortic stenosis involves the differentiation of aortic valve myofibroblasts into osteoblasts. Osteopontin, a proinflammatory glycoprotein, both stimulates differentiation of myofibroblasts and regulates the deposition of calcium by osteoblasts. Osteopontin levels are increased in patients with such conditions as end-stage renal disease, ectopic calcification, and autoimmune disease. We hypothesized that increased plasma osteopontin levels might be associated with the presence of aortic valve calcification and stenosis.

Methods: Venous blood from volunteers older than 65 years undergoing routine echocardiographic analysis or aortic valve surgery for aortic stenosis was collected. Plasma osteopontin levels were measured by means of enzyme-linked immunosorbent assay. The presence of aortic stenosis was defined as an aortic valve area of less than 2.0 cm(2). Aortic valve calcification was assessed by using a validated echocardiographic grading system (1, none; 2, mild; 3, moderate; 4, severe). Comparisons were performed with nonpaired t tests.

Results: Aortic stenosis was present in 23 patients (mean age, 78 years) and was absent in 7 patients (mean age, 72 years). Aortic valve calcification scores were 3.5 +/- 0.6 and 1.3 +/- 0.5 in patients with and without aortic stenosis, respectively (P < .001). Patients with no or mild aortic valve calcification had lower osteopontin levels compared with patients with moderate or severe aortic valve calcification (406.1 +/- 165.8 vs 629.5 +/- 227.5 ng/mL, P = .01). Similarly, patients with aortic stenosis had higher osteopontin levels compared with patients without aortic stenosis (652.2 +/- 218.7 vs 379.7 +/- 159.9 ng/mL, P < .01).

Conclusion: Increased levels of plasma osteopontin are associated with the presence of aortic valve calcification and stenosis. These findings suggest that osteopontin might play a functional role in the pathogenesis of calcific aortic stenosis.
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http://dx.doi.org/10.1016/j.jtcvs.2008.10.045DOI Listing
July 2009

Inhibition of smooth muscle cell migration and neointima formation in vein grafts by overexpression of matrix metalloproteinase-3.

J Vasc Surg 2009 Mar;49(3):750-8

Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany.

Objective: Saphenous vein grafts suffer from neointima formation following bypass surgery. Matrix metalloproteinases (MMPs) play important roles in this process. We examined MMP-3 for its therapeutic potential to prevent smooth muscle cell migration and neointima formation in venous bypass grafts using adenovirus-mediated gene transfer.

Methods: Human aortic smooth muscle cells (HASMC) were transduced with adenoviral vectors encoding ss-galactosidase (Ad.ssgal) [corrected] or human MMP-3 (Ad.hMMP-(3)), [corrected] and characterized for migration in the amniotic membrane stroma as an in vitro model of the vascular wall. Cholesterol-fed New Zealand white rabbits underwent jugular vein bypass grafting into carotid arteries. Before insertion, grafts were incubated ex vivo with either Ad.ssgal [corrected] or hMMP-3. Transgene expression was characterized by immunohistochemistry and in situ zymography. Grafts (n = 6) were explanted after 28 days and intimal hyperplasia was quantified.

Results: Migration of HASMC was significantly reduced when transduced with Ad.hMMP-(3) [corrected] compared to controls (P < .001). Immunocytochemistry of Ad.hMMP-(3) [corrected] transduced venous grafts localized this protein to the intima. In situ-zymography showed increased MMP activity in the intima of Ad.hMMP-(3) [corrected] transfected grafts. Stenosis degree (P = .001), intima/media-ratio (P = .023) and lesion thickness (P = .003) were significantly reduced in grafts transduced with Ad.MMP-3 in comparison to controls. There was no difference inside control groups.

Conclusion: MMP-3 overexpression inhibits formation of intimal hyperplasia in arterialized vein grafts. Adenovirus mediated gene transfer of MMP-3 may be of clinical use to prevent vein graft stenosis following bypass surgery.
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http://dx.doi.org/10.1016/j.jvs.2008.11.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3816542PMC
March 2009

Transforming growth factor-beta 1 (TGF-beta1) induces angiogenesis through vascular endothelial growth factor (VEGF)-mediated apoptosis.

J Cell Physiol 2009 May;219(2):449-58

The Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York, New York 10016, USA.

VEGF and TGF-beta1 induce angiogenesis but have opposing effects on endothelial cells. VEGF protects endothelial cells from apoptosis; TGF-beta1 induces apoptosis. We have previously shown that VEGF/VEGF receptor-2 (VEGFR2) signaling mediates TGF-beta1 induction of apoptosis. This finding raised an important question: Does this mechanism stimulate or inhibit angiogenesis? Here we report that VEGF-mediated apoptosis is required for TGF-beta1 induction of angiogenesis. In vitro the apoptotic effect of TGF-beta1 on endothelial cells is rapid and followed by a long period in which the cells are refractory to apoptosis induction by TGF-beta1. Inhibition of VEGF/VEGFR2 signaling abrogates formation of cord-like structures by TGF-beta1 with an effect comparable to that of z-VAD, an apoptosis inhibitor. Similarly, genetic deficiency of VEGF abolishes TGF-beta1 upregulation of endothelial cell differentiation and formation of vascular structures in embryoid bodies. In vivo TGF-beta1 induces endothelial cell apoptosis as rapidly as in vitro. Inhibition of VEGF blocks TGF-beta1 induction of both apoptosis and angiogenesis, an effect similar to that of z-VAD. Thus, TGF-beta1 induction of angiogenesis requires a rapid and transient apoptotic effect mediated by VEGF/VEGFR2. This novel, unexpected role of VEGF and VEGFR2 indicates VEGF-mediated apoptosis as a potential target to control angiogenesis.
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http://dx.doi.org/10.1002/jcp.21706DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2749291PMC
May 2009

TGF-beta1 induces rearrangement of FLK-1-VE-cadherin-beta-catenin complex at the adherens junction through VEGF-mediated signaling.

J Cell Biochem 2008 Dec;105(6):1367-73

Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, New York 10016, USA.

VEGF and TGF-beta1 induce angiogenesis but have opposing effects on vascular endothelial cells: VEGF promotes survival; TGF-beta1 induces apoptosis. We have previously shown that TGF-beta1 induces endothelial cell apoptosis via up-regulation of VEGF expression and activation of signaling through VEGF receptor-2 (flk-1). In context with TGF-beta1, VEGF signaling is transiently converted from a survival into an apoptotic one. VEGF promotes cell survival in part via activation of PI3K/Akt by a mechanism dependent on the formation of a multi-protein complex that includes flk-1 and the adherens junction proteins VE-cadherin and beta-catenin. Here we report that TGF-beta1 induces rearrangement of the adherens junction complex by separating flk-1 from VE-cadherin and increasing beta-catenin association with both flk-1 and VE-cadherin. This rearrangement is caused neither by changes in adherens junction mRNA or protein expression nor by post-translational modification, and requires VEGF signaling through flk-1. These results show that the adherens junction is an important regulatory component of TGF-beta1-VEGF interaction in endothelial cells.
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http://dx.doi.org/10.1002/jcb.21935DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2588645PMC
December 2008

Topical mitogen-activated protein kinases inhibition reduces intimal hyperplasia in arterialized vein grafts.

J Surg Res 2009 Jun 9;154(1):150-6. Epub 2008 May 9.

The Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, New York 10016, USA.

Objective: Vein graft arterialization results in activation of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinases-1 and -2 (ERK1/2), which have been implicated in cell proliferation, migration, and apoptosis. The goal of our study was to characterize the effect of MAPK inhibition on intimal hyperplasia (IH) in arterialized vein grafts in hypercholesterolemic rabbits.

Methods: Reversed bilateral jugular vein to common carotid artery interposition grafts were constructed in 16 New Zealand White rabbits. The veins were incubated for 30 min prior to grafting with either the synthetic ERK1/2 activation inhibitor UO126 or the control vehicle. Vein graft and control jugular vein were harvested 3 h, 1 d, and 28 d after arterialization for histological and biochemical analyses.

Results: Treatment with UO126 was associated with 31% reduction in mean intimal area (1.68 +/- 0.78 mm(2)versus 2.44 +/- 1.65 mm(2); mean +/- SD; P = 0.036) relative to controls. The intima-to-media ratio of UO126-treated vein grafts decreased by 29% (0.53 +/- 0.04 versus 0.74 +/- 0.06; mean +/- SD; P < 0.01) compared to controls, vehicle-treated vein grafts. There was also significant increase in apoptosis in UO126-treated vein graft medial cell layer at 1 d.

Conclusion: Topical administration of UO126 before vein grafting significantly decreases IH in arterialized vein grafts in hypercholesterolemic rabbits. These results may have significant implications for the development of strategies aimed at blocking or reducing IH in bypass grafts. Therefore, further evaluation of this simple strategy to improve vein graft patency following coronary artery or peripheral vascular bypass surgery is warranted.
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http://dx.doi.org/10.1016/j.jss.2008.04.025DOI Listing
June 2009

Tissue inhibitor of metalloproteinases-2 binding to membrane-type 1 matrix metalloproteinase induces MAPK activation and cell growth by a non-proteolytic mechanism.

J Biol Chem 2008 Jan 8;283(1):87-99. Epub 2007 Nov 8.

Department of Cardiothoracic Surgery, New York University School of Medicine, New York, New York 10016; Department of Cell Biology, New York University School of Medicine, New York, New York 10016. Electronic address:

Membrane-type 1 matrix metalloproteinase (MT1-MMP), a transmembrane proteinase with a short cytoplasmic domain and an extracellular catalytic domain, controls a variety of physiological and pathological processes through the proteolytic degradation of extracellular or transmembrane proteins. MT1-MMP forms a complex on the cell membrane with its physiological protein inhibitor, tissue inhibitor of metalloproteinases-2 (TIMP-2). Here we show that, in addition to extracellular proteolysis, MT1-MMP and TIMP-2 control cell proliferation and migration through a non-proteolytic mechanism. TIMP-2 binding to MT1-MMP induces activation of ERK1/2 by a mechanism that does not require the proteolytic activity and is mediated by the cytoplasmic tail of MT1-MMP. MT1-MMP-mediated activation of ERK1/2 up-regulates cell migration and proliferation in vitro independently of extracellular matrix proteolysis. Proteolytically inactive MT1-MMP promotes tumor growth in vivo, whereas proteolytically active MT1-MMP devoid of cytoplasmic tail does not have this effect. These findings illustrate a novel role for MT1-MMP-TIMP-2 interaction, which controls cell functions by a mechanism independent of extracellular matrix degradation.
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http://dx.doi.org/10.1074/jbc.M705492200DOI Listing
January 2008

Vascular injury and modulation of MAPKs: a targeted approach to therapy of restenosis.

Cell Signal 2007 Jul 15;19(7):1359-71. Epub 2007 Mar 15.

The Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, NY 10016, USA.

Cardiovascular interventions that restore blood circulation to ischemic areas are accompanied by significant tissue damage, which triggers a vascular remodeling response that may result in restenosis of blood conduits. Early endothelial dysfunction and/or impairment is the early event of a cascade that leads, through an inflammatory response and dedifferentiation of medial smooth muscle cells with abundant deposition of extracellular matrix, to intimal hyperplasia. Here we present the molecular and cellular mechanisms of intimal hyperplasia secondary to vascular injury and discuss the potential role of therapeutic modulation of the intracellular signaling pathways that differentially effect vascular endothelial and smooth muscle cells. The role of mitogen-activated protein kinases (MAPKs) and the outcome of their modulation in these processes are highlighted here as they provide a promising therapeutic target for prevention of restenosis.
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http://dx.doi.org/10.1016/j.cellsig.2007.03.002DOI Listing
July 2007

Basic fibroblast growth factor (FGF-2): the high molecular weight forms come of age.

J Cell Biochem 2007 Apr;100(5):1100-8

The Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, New York 10016, USA.

After over thirty years from its discovery, research on basic fibroblast growth factor (FGF-2) keeps revealing new aspects of the complexity of its gene expression as it evolved in the eukaryotic organisms. The discovery of multiple forms of FGF-2 generated by alternative translation from AUG and non-canonical CUG codons on the same mRNA transcript has led to the characterization of a low molecular weight (LMW) FGF-2 form and various high molecular weight (HMW) forms (four in humans). In this review, we discuss the biochemical features and biological activities of the different FGF-2 forms. In particular, we focus on the properties that are unique to the HMW forms and its biological functions.
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http://dx.doi.org/10.1002/jcb.21116DOI Listing
April 2007

VEGF, a prosurvival factor, acts in concert with TGF-beta1 to induce endothelial cell apoptosis.

Proc Natl Acad Sci U S A 2006 Nov 6;103(46):17260-5. Epub 2006 Nov 6.

The Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, NY 10016, USA.

VEGF and TGF-beta1 are potent angiogenesis inducers with opposing effects on endothelial cells. TGF-beta1 induces apoptosis; VEGF protects endothelial cells from apoptosis. We found that TGF-beta1 promotes endothelial cell expression of FGF-2, which up-regulates VEGF synthesis. Inhibition of VEGF signaling through VEGF receptor 2 (flk-1) abrogates TGF-beta1-induced apoptosis and p38(MAPK) activation. Inhibition of p38(MAPK) blocks TGF-beta1-induced apoptosis, showing that VEGF/flk-1-mediated activation of p38(MAPK) is required for TGF-beta1 induction of apoptosis. In the absence of TGF-beta1, VEGF activates p38(MAPK) and promotes endothelial cell survival. However, in context with TGF-beta1, VEGF/flk-1-mediated activation of p38(MAPK) results in apoptosis. Thus, cross-talk between TGF-beta1 and VEGF signaling converts VEGF/flk-1-activated p38(MAPK) into a proapoptotic signal. This finding illustrates an unexpected role of VEGF and indicates that VEGF can be pharmacologically converted into an apoptotic factor, a novel approach to antiangiogenesis therapy.
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http://dx.doi.org/10.1073/pnas.0605556103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1859920PMC
November 2006

Mechanisms of c-reactive protein up-regulation in arterialized vein grafts.

Surgery 2006 Feb;139(2):254-62

Seymour Cohn Cardiovascular Research Laboratory, Department of Cardiothoracic Surgery, New York, New York, USA.

Background: C-reactive protein (CRP), an acute phase reactant, is an independent predictor of coronary artery syndromes and a mediator of the vascular response to injury. CRP has been found in arterialized vein grafts and has been linked to atherogenesis; however, its involvement in vein graft early failure or intimal hyperplasia has not been assessed. This study was designed to investigate the mechanism(s) of CRP up-regulation in arterialized vein grafts.

Methods: Carotid artery bypass with arterialized jugular vein grafts (AVG) was performed in 18 dogs. AVG were harvested at 3, 8, and 24 hours and 4, 14, and 28 days, using the femoral vein obtained at the time of AVG harvest as a control. Serum CRP levels were characterized by enzyme-linked immunosorbent assay; AVG expression of CRP was studied by immunofluorescence, Western blotting, in situ hybridization, Northern blotting, and quantitative RT-PCR.

Results: CRP levels peaked at 24 hours in serum and AVG but remained at baseline in control veins. By double immunofluorescence, CRP was associated with the media and adventitia of AVG. However, Northern blotting analysis showed no CRP mRNA expression in AVG. Reverse transcriptase polymerase chain reaction analysis confirmed the lack of up-regulation of CRP in AVG.

Conclusion: CRP levels are increased in AVG, peaking 24 hours after arterialization. However, no significant production of CRP was detected in AVG. Therefore, increased CRP levels within AVG appear to originate mostly from CRP diffusion from the systemic circulation. These results have significant implications for the development of strategies aimed at blocking CRP up-regulation in bypass grafts.
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http://dx.doi.org/10.1016/j.surg.2005.08.002DOI Listing
February 2006

Anti-proliferative and anti-inflammatory effects of topical MAPK inhibition in arterialized vein grafts.

FASEB J 2006 Feb 22;20(2):398-400. Epub 2005 Nov 22.

The Seymour Cohn Cardiovascular Surgical Research Laboratory, Department of Cardiothoracic Surgery, New York University School of Medicine, New York, New York 10016, USA.

Vein graft failure following bypass surgery is a frequent and important clinical problem. The vascular injury caused by arterialization is responsible for vein graft intimal hyperplasia, a lesion generated by medial smooth muscle cell proliferation and migration into the intima, increased extracellular matrix deposition, and formation of a thick neointima. Development of the neointima into a typical atherosclerotic lesion and consequent stenosis ultimately result in vein graft failure. Endothelial damage, inflammation, and intracellular signaling through mitogen-activated protein kinases (MAPKs) have been implicated in the early stages of this process. We therefore investigated the effects of topical inhibition of ERK-1/2 MAPK activation on vascular cell proliferation and apoptosis, and on the inflammatory response in a canine model of vein graft arterialization. For this purpose, vein grafts were incubated with the MEK-1/2 inhibitor, UO126, ex vivo for 30 min before grafting. This treatment effectively abolished arterialization-induced ERK-1/2 activation, decreased medial cell proliferation, and increased apoptosis. UO126 treatment also inhibited the vein graft infiltration by myeloperoxidase-positive inflammatory cells that follows vein graft arterialization. Thus, topical ex vivo administration of MAPK inhibitors can provide a pharmacological tool to prevent or reduce the vascular cell responses that lead to vein graft intimal hyperplasia and graft failure.
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http://dx.doi.org/10.1096/fj.05-4114fjeDOI Listing
February 2006

Matrix metalloproteinase expression in vein grafts: role of inflammatory mediators and extracellular signal-regulated kinases-1 and -2.

Am J Physiol Heart Circ Physiol 2006 Apr 11;290(4):H1651-9. Epub 2005 Nov 11.

Depts. of Cardiothoracic Surgery, New York Univesity School of Medicine, New York, NY 10016, USA.

Matrix metalloproteinases (MMPs) play key roles in vascular remodeling. We characterized the role of inflammatory mediators and extracellular signal-regulated kinases (ERKs) in the control of arterialized vein graft expression of MMP-9, MMP-2, and membrane-type 1-MMP (MT1-MMP) and of the tissue inhibitor of metalloproteinases-2 (TIMP-2). For this purpose we used a canine model of jugular vein to carotid artery interposition graft and analyzed the vein grafts at various postoperative times (30 min to 28 days) using the contralateral vein as a control. To study the role of ERK-1/2, veins were incubated with the mitogen-activated protein kinase kinase (MEK-1/2) inhibitor UO126 for 30 min before being grafted. Vein graft extracts were analyzed for MMPs, TIMP-2, tumor necrosis factor-alpha (TNF-alpha), polymorphonuclear neutrophil (PMN) infiltration, myeloperoxidase (MPO), and thrombin activity, and for ERK-1/2 activation. Vein graft arterialization resulted in rapid and sustained (8 h to 28 days) upregulation of vein graft-associated MMP-9, MMP-2, MT1-MMP, thrombin activity, and TNF-alpha levels with concomitant TIMP-2 downregulation. MMP-2 activation preceded MT1-MMP upregulation. PMN infiltration and vein graft-associated MPO activity increased within hours after arterialization, indicating a prompt, local inflammatory response. In cultured smooth muscle cells, both thrombin and TNF-alpha upregulated MT1-MMP expression; however, only thrombin activated MMP-2. Inhibition of ERK-1/2 activation blocked arterialization-induced upregulation of MMP-2, MMP-9, and MT1-MMP. Thus, thrombin, inflammatory mediators, and activation of the ERK-1/2 pathway control MMP and TIMP-2 expression in arterialized vein grafts.
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http://dx.doi.org/10.1152/ajpheart.00530.2005DOI Listing
April 2006

PDGF-BB induces vascular smooth muscle cell expression of high molecular weight FGF-2, which accumulates in the nucleus.

J Cell Biochem 2005 Aug;95(6):1292-300

The Seymour Cohn Cardiovascular Surgery Research Laboratory, Department of Cardiothoracic Surgery, New York, New York 10016, USA.

Basic fibroblast growth factor (FGF-2) and platelet-derived growth factor (PDGF) are implicated in vascular remodeling secondary to injury. Both growth factors control vascular endothelial and smooth muscle cell proliferation, migration, and survival through overlapping intracellular signaling pathways. In vascular smooth muscle cells PDGF-BB induces FGF-2 expression. However, the effect of PDGF on the different forms of FGF-2 has not been elucidated. Here, we report that treatment of vascular aortic smooth muscle cells with PDGF-BB rapidly induces expression of 20.5 and 21 kDa, high molecular weight (HMW) FGF-2 that accumulates in the nucleus and nucleolus. Conversely, PDGF treatment has little or no effect on 18 kDa, low-molecular weight FGF-2 expression. PDGF-BB-induced upregulation of HMW FGF-2 expression is controlled by sustained activation of extracellular signal-regulated kinase (ERK)-1/2 and is abolished by actinomycin D. These data describe a novel interaction between PDGF-BB and FGF-2, and indicate that the nuclear forms of FGF-2 may mediate the effect of PDGF activity on vascular smooth muscle cells.
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http://dx.doi.org/10.1002/jcb.20505DOI Listing
August 2005

Proteases and extracellular environment.

Thromb Haemost 2005 Feb;93(2):190-1

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February 2005

Vein graft arterialization causes differential activation of mitogen-activated protein kinases.

J Thorac Cardiovasc Surg 2004 May;127(5):1276-84

Seymour Cohn Cardiovascular Research Laboratory, Division of Cardiothoracic Surgery, Department of Surgery, New York University School of Medicine, New York 10016, USA.

Objective: Vascular injury results in activation of the mitogen-activated protein kinases-extracellular-signal regulated kinases, c-jun N-terminal kinase, and p38(MAPK)-which have been implicated in cell proliferation, migration, and apoptosis. The goal of this study was to characterize mitogen-activated protein kinase activation in arterialized vein grafts.

Methods: Carotid artery bypass using reversed external jugular vein was performed in 29 dogs. Vein grafts were harvested after 30 minutes and 3, 8, and 24 hours, and 4, 7, 14, and 28 days. Contralateral external jugular vein and external jugular vein interposition vein-to-vein grafts were used as controls. Vein graft extracts were analyzed for extracellular-signal regulated kinases, c-jun N-terminal kinase, and p38(MAPK) activation. Proliferating cell nuclear antigen expression was investigated as a parameter of cell proliferation. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling staining and intimal hyperplasia by morphometric examination of tissue sections.

Results: Significant intimal hyperplasia was observed at 28 days. Over the time points studied, vein graft arterialization resulted in bimodal activation of both extracellular-signal regulated kinase and p38(MAPK) (30 minutes through 3 hours; 4 days) but did not induce activation of c-jun N-terminal kinase. Proliferating cell nuclear antigen expression increased from days 1 through 28, and apoptosis increased between 8 and 24 hours.

Conclusion: Vein graft arterialization induces bimodal activation of extracellular-signal regulated kinase and p38(MAPK); however, in contrast with what is described in arterial injury, it does not induce c-jun N-terminal kinase activation. These results provide the first comprehensive characterization of the mitogen-activated protein kinase signaling pathways activated in vein graft arterialization and identify mitogen-activated protein kinases as potential mediators of vein graft remodeling and subsequent intimal hyperplasia.
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http://dx.doi.org/10.1016/j.jtcvs.2003.07.017DOI Listing
May 2004

Induction of stromelysin-1 (MMP-3) by fibroblast growth factor-2 (FGF-2) in FGF-2-/- microvascular endothelial cells requires prolonged activation of extracellular signal-regulated kinases-1 and -2 (ERK-1/2).

J Cell Biochem 2003 Dec;90(5):1015-25

The Seymour Cohn Cardiovascular Surgery Research Laboratory, New York University School of Medicine, New York, New York 10016, USA.

Basic fibroblast growth factor (FGF-2) and matrix metalloproteinases (MMPs) play key roles in vascular remodeling. Because FGF-2 controls a number of proteolytic activities in various cell types, we tested its effect on vascular endothelial cell expression of MMP-3 (stromelysin-1), a broad-spectrum proteinase implicated in coronary atherosclerosis. Endothelial cells (EC) from FGF-2-/- mice are highly responsive to exogenous FGF-2 and were therefore used for this study. The results showed that treatment of microvascular EC with human recombinant FGF-2 results in strong induction of MMP-3 mRNA and protein expression. Upregulation of MMP-3 mRNA by FGF-2 requires de novo protein synthesis and activation of the ERK-1/2 pathway. FGF-2 concentrations (5-10 ng/ml) that induce rapid and prolonged (24 h) activation of ERK-1/2 upregulate MMP-3 expression. In contrast, lower concentrations (1-2 ng/ml) that induce robust but transient (<8 h) ERK-1/2 activation are ineffective. Inhibition of ERK-1/2 activation at different times (-0.5 h to +8 h) of EC treatment with effective FGF-2 concentrations blocks MMP-3 upregulation. Thus, FGF-2 induces EC expression of MMP-3 with a threshold dose effect that requires sustained activation of the ERK-1/2 pathway. Because FGF-2 controls other EC functions with a linear dose effect, these features indicate a unique role of MMP-3 in vascular remodeling.
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http://dx.doi.org/10.1002/jcb.10721DOI Listing
December 2003