TY - JOUR T1 - Claudin-like protein 24 interacts with the VEGFR-2 and VEGFR-3 pathways and regulates lymphatic vessel development JF - Genes Dev Y1 - 2010 A1 - Saharinen, Pipsa A1 - Helotera, Hanna A1 - Miettinen, Juho A1 - Norrmen, Camilla A1 - D'Amico, Gabriela A1 - Jeltsch, Michael A1 - Langenberg, Tobias A1 - Vandevelde, Wouter A1 - Ny, Annelii A1 - Dewerchin, Mieke A1 - Carmeliet, Peter A1 - Alitalo, Kari AB - The Claudin-like protein of 24 kDa (CLP24) is a hypoxia-regulated transmembrane protein of unknown function. We show here that clp24 knockdown in Danio rerio and Xenopus laevis results in defective lymphatic development. Targeted disruption of Clp24 in mice led to enlarged lymphatic vessels having an abnormal smooth muscle cell coating. We also show that the Clp24(-/-) phenotype was further aggravated in the Vegfr2(+/LacZ) or Vegfr3(+/LacZ) backgrounds and that CLP24 interacts with vascular endothelial growth factor receptor-2 (VEGFR-2) and VEGFR-3 and attenuates the transcription factor CREB phosphorylation via these receptors. Our results indicate that CLP24 is a novel regulator of VEGFR-2 and VEGFR-3 signaling pathways and of normal lymphatic vessel structure. VL - 24 UR - http://view.ncbi.nlm.nih.gov/pubmed/20439428 IS - 9 JO - Genes & Development ER - TY - JOUR T1 - Reevaluation of the role of VEGF-B suggests a restricted role in the revascularization of the ischemic myocardium JF - Arterioscler Thromb Vasc Biol Y1 - 2008 A1 - Li, Xuri A1 - Tjwa, Marc A1 - Van Hove, Inge A1 - Enholm, Berndt A1 - Neven, Elke A1 - Paavonen, Karri A1 - Jeltsch, Michael A1 - Juan, Toni Diez A1 - Sievers, Richard E A1 - Chorianopoulos, Emmanuel A1 - Wada, Hiromichi A1 - Vanwildemeersch, Maarten A1 - Noel, Agnes A1 - Foidart, Jean-Michel A1 - Springer, Matthew L A1 - von Degenfeld, Georges A1 - Dewerchin, Mieke A1 - Blau, Helen M A1 - Alitalo, Kari A1 - Eriksson, Ulf A1 - Carmeliet, Peter A1 - Moons, Lieve AB - OBJECTIVE: The endogenous role of the VEGF family member vascular endothelial growth factor-B (VEGF-B) in pathological angiogenesis remains unclear. METHODS AND RESULTS: We studied the role of VEGF-B in various models of pathological angiogenesis using mice lacking VEGF-B (VEGF-B(-/-)) or overexpressing VEGF-B(167). After occlusion of the left coronary artery, VEGF-B deficiency impaired vessel growth in the ischemic myocardium whereas, in wild-type mice, VEGF-B(167) overexpression enhanced revascularization of the infarct and ischemic border zone. By contrast, VEGF-B deficiency did not affect vessel growth in the wounded skin, hypoxic lung, ischemic retina, or ischemic limb. Moreover, VEGF-B(167) overexpression failed to enhance vascular growth in the skin or ischemic limb. CONCLUSIONS: VEGF-B appears to have a relatively restricted angiogenic activity in the ischemic heart. These insights might offer novel therapeutic opportunities. VL - 28 UR - http://view.ncbi.nlm.nih.gov/pubmed/18511699 IS - 9 JO - Arteriosclerosis, Thrombosis, and Vascular Biology ER - TY - JOUR T1 - Intrinsic versus microenvironmental regulation of lymphatic endothelial cell phenotype and function JF - FASEB J Y1 - 2003 A1 - Veikkola, Tanja A1 - Lohela, Marja A1 - Ikenberg, Kristian A1 - Mäkinen, Taija A1 - Korff, Thomas A1 - Saaristo, Anne A1 - Petrova, Tatania A1 - Jeltsch, Michael A1 - Augustin, Hellmut G A1 - Alitalo, Kari AB - Vascular endothelial cells are characterized by a high degree of functional and phenotypic plasticity, which is controlled both by their pericellular microenvironment and their intracellular gene expression programs. To gain further insight into the mechanisms regulating the endothelial cell phenotype, we have compared the responses of lymphatic endothelial cells (LECs) and blood vascular endothelial cells (BECs) to vascular endothelial growth factors (VEGFs). VEGFR-3-specific signals are sufficient for LEC but not BEC proliferation, as shown by the ability of the specific ligand VEGF-C156S to stimulate cell cycle entry only in LECs. On the other hand, we found that VEGFR-3 stimulation did not induce LEC cell shape changes typical of VEGFR-2-stimulated LECs, indicating receptor-specific differences in the cytoskeletal responses. Genes induced via VEGFR-2 also differed between BECs and LECs: angiopoietin-2 (Ang-2) was induced via VEGFR-2 in BECs and LECs, but the smooth muscle cell (SMC) chemoattractant BMP-2 was induced only in BECs. Both BECs and LECs were able to promote SMC chemotaxis, but contact with SMCs led to down-regulation of VEGFR-3 expression in BECs in a 3-dimensional coculture system. This was consistent with the finding that VEGFR-3 is down-regulated in vivo at sites of endothelial cell-pericyte/smooth muscle cell contacts. Collectively, these data show intrinsic cell-specific differences of BEC and LEC responses to VEGFs and identify a pericellular regulatory mechanism for VEGFR-3 down-regulation in endothelial cells. VL - 17 UR - http://view.ncbi.nlm.nih.gov/pubmed/14597670 IS - 14 JO - The FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology ER - TY - JOUR T1 - Adenoviral VEGF-C overexpression induces blood vessel enlargement, tortuosity, and leakiness but no sprouting angiogenesis in the skin or mucous membranes JF - FASEB J Y1 - 2002 A1 - Saaristo, Anne A1 - Veikkola, Tanja A1 - Enholm, Berndt A1 - Hytönen, Maija A1 - Arola, Johanna A1 - Pajusola, Katri A1 - Turunen, Païvi A1 - Jeltsch, Michael A1 - Karkkainen, Marika J A1 - Kerjaschki, Dontscho A1 - Bueler, Hansruedi A1 - Ylä-Herttuala, Seppo A1 - Alitalo, Kari AB - Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are important regulators of blood and lymphatic vessel growth and vascular permeability. The VEGF-C/VEGFR-3 signaling pathway is crucial for lymphangiogenesis, and heterozygous inactivating missense mutations of the VEGFR-3 gene are associated with hereditary lymphedema. However, VEGF-C can have potent effects on blood vessels because its receptor VEGFR-3 is expressed in certain blood vessels and because the fully processed form of VEGF-C also binds to the VEGFR-2 of blood vessels. To characterize the in vivo effects of VEGF-C on blood and lymphatic vessels, we have overexpressed VEGF-C via adenovirus- and adeno-associated virus-mediated transfection in the skin and respiratory tract of athymic nude mice. This resulted in dose-dependent enlargement and tortuosity of veins, which, along with the collecting lymphatic vessels were found to express VEGFR-2. Expression of angiopoietin 1 blocked the increased leakiness of the blood vessels induced by VEGF-C whereas vessel enlargement and lymphangiogenesis were not affected. However, angiogenic sprouting of new blood vessels was not observed in response to AdVEGF-C or AAV-VEGF-C. These results show that virally produced VEGF-C induces blood vessel changes, including vascular leak, but its angiogenic potency is much reduced compared with VEGF in normal skin. VL - 16 UR - http://view.ncbi.nlm.nih.gov/pubmed/12087065 IS - 9 JO - The FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology ER - TY - JOUR T1 - Signalling via vascular endothelial growth factor receptor-3 is sufficient for lymphangiogenesis in transgenic mice JF - EMBO J Y1 - 2001 A1 - Veikkola, T A1 - Jussila, L A1 - Makinen, T A1 - Karpanen, T A1 - Jeltsch, M A1 - Petrova, T V A1 - Kubo, H A1 - Thurston, G A1 - McDonald, D M A1 - Achen, M G A1 - Stacker, S A A1 - Alitalo, K AB - Vascular endothelial growth factor receptor-3 (VEGFR-3) has an essential role in the development of embryonic blood vessels; however, after midgestation its expression becomes restricted mainly to the developing lymphatic vessels. The VEGFR-3 ligand VEGF-C stimulates lymphangiogenesis in transgenic mice and in chick chorioallantoic membrane. As VEGF-C also binds VEGFR-2, which is expressed in lymphatic endothelia, it is not clear which receptors are responsible for the lymphangiogenic effects of VEGF-C. VEGF-D, which binds to the same receptors, has been reported to induce angiogenesis, but its lymphangiogenic potential is not known. In order to define the lymphangiogenic signalling pathway we have created transgenic mice overexpressing a VEGFR-3-specific mutant of VEGF-C (VEGF-C156S) or VEGF-D in epidermal keratinocytes under the keratin 14 promoter. Both transgenes induced the growth of lymphatic vessels in the skin, whereas the blood vessel architecture was not affected. Evidence was also obtained that these growth factors act in a paracrine manner in vivo. These results demonstrate that stimulation of the VEGFR-3 signal transduction pathway is sufficient to induce specifically lymphangiogenesis in vivo. VL - 20 UR - http://view.ncbi.nlm.nih.gov/pubmed/11250889 IS - 6 JO - The EMBO Journal ER - TY - CONF T1 - Signalling via VEGFR-3 is sufficient for lymphangiogenesis in transgenic mice. T2 - Molecular Targets and Cancer Therapeutics: Discovery, Biology, and Clinical Applications Y1 - 2001 A1 - Jussila, L. A1 - Veikkola, T. A1 - Jeltsch, M. A1 - Thurston, G. A1 - McDonald, D. A1 - Achen, M. A1 - Stacker, S. A1 - Alitalo, K. JF - Molecular Targets and Cancer Therapeutics: Discovery, Biology, and Clinical Applications CY - Miami Beach, Florida ER - TY - JOUR T1 - Vascular endothelial growth factor D (VEGF-D) is a ligand for the tyrosine kinases VEGF receptor 2 (Flk1) and VEGF receptor 3 (Flt4) JF - Proc Natl Acad Sci U S A Y1 - 1998 A1 - Achen, M G A1 - Jeltsch, M A1 - Kukk, E A1 - Mäkinen, T A1 - Vitali, A A1 - Wilks, A F A1 - Alitalo, K A1 - Stacker, S A AB - We have identified a member of the VEGF family by computer-based homology searching and have designated it VEGF-D. VEGF-D is most closely related to VEGF-C by virtue of the presence of N- and C-terminal extensions that are not found in other VEGF family members. In adult human tissues, VEGF-D mRNA is most abundant in heart, lung, skeletal muscle, colon, and small intestine. Analyses of VEGF-D receptor specificity revealed that VEGF-D is a ligand for both VEGF receptors (VEGFRs) VEGFR-2 (Flk1) and VEGFR-3 (Flt4) and can activate these receptors. However. VEGF-D does not bind to VEGFR-1. Expression of a truncated derivative of VEGF-D demonstrated that the receptor-binding capacities reside in the portion of the molecule that is most closely related in primary structure to other VEGF family members and that corresponds to the mature form of VEGF-C. In addition, VEGF-D is a mitogen for endothelial cells. The structural and functional similarities between VEGF-D and VEGF-C define a subfamily of the VEGFs. VL - 95 UR - http://view.ncbi.nlm.nih.gov/pubmed/9435229 IS - 2 JO - Proceedings of the National Academy of Sciences of the United States of America ER -