TY - JOUR T1 - Effective suppression of vascular network formation by combination of antibodies blocking VEGFR ligand binding and receptor dimerization JF - Cancer Cell Y1 - 2010 A1 - Tvorogov, Denis A1 - Anisimov, Andrey A1 - Zheng, Wei A1 - Leppänen, Veli-Matti A1 - Tammela, Tuomas A1 - Laurinavicius, Simonas A1 - Holnthoner, Wolfgang A1 - Heloterä, Hanna A1 - Holopainen, Tanja A1 - Jeltsch, Michael A1 - Kalkkinen, Nisse A1 - Lankinen, Hilkka A1 - Ojala, Päivi M A1 - Alitalo, Kari AB - Antibodies that block vascular endothelial growth factor (VEGF) have become an integral part of antiangiogenic tumor therapy, and antibodies targeting other VEGFs and receptors (VEGFRs) are in clinical trials. Typically receptor-blocking antibodies are targeted to the VEGFR ligand-binding site. Here we describe a monoclonal antibody that inhibits VEGFR-3 homodimer and VEGFR-3/VEGFR-2 heterodimer formation, signal transduction, as well as ligand-induced migration and sprouting of microvascular endothelial cells. Importantly, we show that combined use of antibodies blocking ligand binding and receptor dimerization improves VEGFR inhibition and results in stronger inhibition of endothelial sprouting and vascular network formation in vivo. These results suggest that receptor dimerization inhibitors could be used to enhance antiangiogenic activity of antibodies blocking ligand binding in tumor therapy. VL - 18 UR - http://view.ncbi.nlm.nih.gov/pubmed/21130043 IS - 6 JO - Cancer Cell ER - TY - JOUR T1 - Vascular endothelial growth factor-B acts as a coronary growth factor in transgenic rats without inducing angiogenesis, vascular leak, or inflammation JF - Circulation Y1 - 2010 A1 - Bry, Maija A1 - Kivelä, Riikka A1 - Holopainen, Tanja A1 - Anisimov, Andrey A1 - Tammela, Tuomas A1 - Soronen, Jarkko A1 - Silvola, Johanna A1 - Saraste, Antti A1 - Jeltsch, Michael A1 - Korpisalo, Petra A1 - Carmeliet, Peter A1 - Lemström, Karl B A1 - Shibuya, Masabumi A1 - Ylä-Herttuala, Seppo A1 - Alhonen, Leena A1 - Mervaala, Eero A1 - Andersson, Leif C A1 - Knuuti, Juhani A1 - Alitalo, Kari AB - BACKGROUND: Vascular endothelial growth factor-B (VEGF-B) binds to VEGF receptor-1 and neuropilin-1 and is abundantly expressed in the heart, skeletal muscle, and brown fat. The biological function of VEGF-B is incompletely understood. METHODS AND RESULTS: Unlike placenta growth factor, which binds to the same receptors, adeno-associated viral delivery of VEGF-B to mouse skeletal or heart muscle induced very little angiogenesis, vascular permeability, or inflammation. As previously reported for the VEGF-B(167) isoform, transgenic mice and rats expressing both isoforms of VEGF-B in the myocardium developed cardiac hypertrophy yet maintained systolic function. Deletion of the VEGF receptor-1 tyrosine kinase domain or the arterial endothelial Bmx tyrosine kinase inhibited hypertrophy, whereas loss of VEGF-B interaction with neuropilin-1 had no effect. Surprisingly, in rats, the heart-specific VEGF-B transgene induced impressive growth of the epicardial coronary vessels and their branches, with large arteries also seen deep inside the subendocardial myocardium. However, VEGF-B, unlike other VEGF family members, did not induce significant capillary angiogenesis, increased permeability, or inflammatory cell recruitment. CONCLUSIONS: VEGF-B appears to be a coronary growth factor in rats but not in mice. The signals for the VEGF-B-induced cardiac hypertrophy are mediated at least in part via the endothelium. Because cardiomyocyte damage in myocardial ischemia begins in the subendocardial myocardium, the VEGF-B-induced increased arterial supply to this area could have therapeutic potential in ischemic heart disease. VL - 122 UR - http://view.ncbi.nlm.nih.gov/pubmed/20937974 IS - 17 JO - Circulation ER - TY - JOUR T1 - Distinct architecture of lymphatic vessels induced by chimeric vascular endothelial growth factor-C/vascular endothelial growth factor heparin-binding domain fusion proteins JF - Circ Res Y1 - 2007 A1 - Tammela, Tuomas A1 - He, Yulong A1 - Lyytikkä, Johannes A1 - Jeltsch, Michael A1 - Markkanen, Johanna A1 - Pajusola, Katri A1 - Ylä-Herttuala, Seppo A1 - Alitalo, Kari AB - Vascular endothelial growth factor (VEGF)-C and VEGF-D are composed of the receptor-binding VEGF homology domain and a carboxy-terminal silk homology domain that requires proteolytic cleavage for growth factor activation. Here, we explored whether the C-terminal heparin-binding domain of the VEGF(165) or VEGF(189) isoform also containing neuropilin-binding sequences could substitute for the silk homology domain of VEGF-C. Such VEGF-C/VEGF-heparin-binding domain chimeras were produced and shown to activate VEGF-C receptors, and, when expressed in tissues via adenovirus or adeno-associated virus vectors, stimulated lymphangiogenesis in vivo. However, both chimeras induced a distinctly different pattern of lymphatic vessels when compared with VEGF-C. Whereas VEGF-C-induced vessels were initially a dense network of small diameter vessels, the lymphatic vessels induced by the chimeric growth factors tended to form directly along tissue borders, along basement membranes that are rich in heparan sulfate. For example, in skeletal muscle, the chimeras induced formation of lumenized lymphatic vessels more efficiently than wild-type VEGF-C. We conclude that the matrix-binding domain of VEGF can target VEGF-C activity to heparin-rich basement membrane structures. These properties may prove useful for tissue engineering and attempts to regenerate lymphatic vessels in lymphedema patients. VL - 100 UR - http://view.ncbi.nlm.nih.gov/pubmed/17478733 IS - 10 JO - Circulation Research ER - TY - JOUR T1 - Enhanced capillary formation stimulated by a chimeric vascular endothelial growth factor/vascular endothelial growth factor-C silk domain fusion protein JF - Circ Res Y1 - 2007 A1 - Keskitalo, Salla A1 - Tammela, Tuomas A1 - Lyytikka, Johannes A1 - Karpanen, Terhi A1 - Jeltsch, Michael A1 - Markkanen, Johanna A1 - Yla-Herttuala, Seppo A1 - Alitalo, Kari AB - Vascular endothelial growth factor (VEGF)-C and VEGF-D require proteolytic cleavage of the carboxy terminal silk-homology domain for activation. To study the functions of the VEGF-C propeptides, we engineered a chimeric growth factor protein, VEGF-CAC, composed of the amino- and carboxy-terminal propeptides of VEGF-C fused to the receptor-activating core domain of VEGF. Like VEGF-C, VEGF-CAC underwent proteolytic cleavage, and like VEGF, it bound to and activated VEGF receptor-1 and VEGF receptor-2, but not the VEGF-C receptor VEGF receptor-3. VEGF-CAC also bound to neuropilins in a heparin-dependent manner. Strikingly, when VEGF-CAC was expressed via an adenovirus vector in the ear skin of immunodeficient mice, it proved to be a more potent inducer of capillary angiogenesis than VEGF. The VEGF-CAC-induced vessels differed greatly from those induced by VEGF, as they formed a very dense and fine network of pericyte and basement membrane-covered capillaries that were functional, as shown by lectin perfusion experiments. VEGF-CAC could prove useful in proangiogenic therapies in patients experiencing tissue ischemia. VL - 100 UR - http://view.ncbi.nlm.nih.gov/pubmed/17478734 IS - 10 JO - Circulation Research ER - TY - JOUR T1 - Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation JF - J Clin Invest Y1 - 2005 A1 - Baluk, Peter A1 - Tammela, Tuomas A1 - Ator, Erin A1 - Lyubynska, Natalya A1 - Achen, Marc G A1 - Hicklin, Daniel J A1 - Jeltsch, Michael A1 - Petrova, Tatiana V A1 - Pytowski, Bronislaw A1 - Stacker, Steven A A1 - Ylä-Herttuala, Seppo A1 - Jackson, David G A1 - Alitalo, Kari A1 - McDonald, Donald M AB - Edema occurs in asthma and other inflammatory diseases when the rate of plasma leakage from blood vessels exceeds the drainage through lymphatic vessels and other routes. It is unclear to what extent lymphatic vessels grow to compensate for increased leakage during inflammation and what drives the lymphangiogenesis that does occur. We addressed these issues in mouse models of (a) chronic respiratory tract infection with Mycoplasma pulmonis and (b) adenoviral transduction of airway epithelium with VEGF family growth factors. Blood vessel remodeling and lymphangiogenesis were both robust in infected airways. Inhibition of VEGFR-3 signaling completely prevented the growth of lymphatic vessels but not blood vessels. Lack of lymphatic growth exaggerated mucosal edema and reduced the hypertrophy of draining lymph nodes. Airway dendritic cells, macrophages, neutrophils, and epithelial cells expressed the VEGFR-3 ligands VEGF-C or VEGF-D. Adenoviral delivery of either VEGF-C or VEGF-D evoked lymphangiogenesis without angiogenesis, whereas adenoviral VEGF had the opposite effect. After antibiotic treatment of the infection, inflammation and remodeling of blood vessels quickly subsided, but lymphatic vessels persisted. Together, these findings suggest that when lymphangiogenesis is impaired, airway inflammation may lead to bronchial lymphedema and exaggerated airflow obstruction. Correction of defective lymphangiogenesis may benefit the treatment of asthma and other inflammatory airway diseases. VL - 115 UR - http://view.ncbi.nlm.nih.gov/pubmed/15668734 IS - 2 JO - The Journal of Clinical Investigation ER - TY - JOUR T1 - Genesis and pathogenesis of lymphatic vessels JF - Cell Tissue Res Y1 - 2003 A1 - Jeltsch, Michael A1 - Tammela, Tuomas A1 - Alitalo, Kari A1 - Wilting, Jörg AB - The lymphatic system is generally regarded as supplementary to the blood vascular system, in that it transports interstitial fluid, macromolecules, and immune cells back into the blood. However, in insects, the open hemolymphatic (or lymphohematic) system ensures the circulation of immune cells and interstitial fluid through the body. The Drosophila homolog of the mammalian vascular endothelial growth factor receptor (VEGFR) gene family is expressed in hemocytes, suggesting a close relationship to the endothelium that develops later in phylogeny. Lymph hearts are typical organs for the propulsion of lymph in lower vertebrates and are still transiently present in birds. The lymphatic endothelial marker VEGFR-3 is transiently expressed in embryonic blood vessels and is crucial for their development. We therefore regard the question of whether the blood vascular system or the lymphatic system is primary or secondary as open. Future molecular comparisons should be performed without any bias based on the current prevalence of the blood vascular system over the lymphatic system. Here, we give an overview of the structure, function, and development of the lymphatics, with special emphasis on the recently discovered lymphangiogenic growth factors. VL - 314 UR - http://view.ncbi.nlm.nih.gov/pubmed/12942362 IS - 1 JO - Cell and Tissue Research ER -