TY - JOUR T1 - Lymphatics and the eye. [Finnish] JF - Duodecim Lääketieteellinen Aikakauskirja Y1 - 2020 A1 - Gucciardo, Erika A1 - Lehti, Timo A. A1 - Korhonen, Ani A1 - Salvén, Petri A1 - Lehti, Kaisa A1 - Jeltsch, Michael A1 - Loukovaara, Sirpa VL - 136 UR - https://www.duodecimlehti.fi/lehti/2020/16/duo15739 IS - 16 JO - Duodecim ER - TY - JOUR T1 - KLK3/PSA and cathepsin D activate VEGF-C and VEGF-D JF - eLife Y1 - 2019 A1 - Jha, Sawan Kumar A1 - Rauniyar, Khushbu A1 - Chronowska, Ewa A1 - Mattonet, Kenny A1 - Maina, Eunice Wairimu A1 - Koistinen, Hannu A1 - Stenman, Ulf-Håkan A1 - Alitalo, Kari A1 - Jeltsch, Michael KW - cancer biology KW - Cathepsin D KW - kallikrein-related peptidases KW - KLK3/PSA KW - Lymphangiogenesis KW - mouse KW - VEGF-C KW - VEGF-D AB - Vascular endothelial growth factor-C (VEGF-C) acts primarily on endothelial cells, but also on non-vascular targets, e.g. in the CNS and immune system. Here we describe a novel, unique VEGF-C form in the human reproductive system produced via cleavage by kallikrein-related peptidase 3 (KLK3), aka prostate-specific antigen (PSA). KLK3 activated VEGF-C specifically and efficiently through cleavage at a novel N-terminal site. We detected VEGF-C in seminal plasma, and sperm liquefaction occurred concurrently with VEGF-C activation, which was enhanced by collagen and calcium binding EGF domains 1 (CCBE1). After plasmin and ADAMTS3, KLK3 is the third protease shown to activate VEGF-C. Since differently activated VEGF-Cs are characterized by successively shorter N-terminal helices, we created an even shorter hypothetical form, which showed preferential binding to VEGFR-3. Using mass spectrometric analysis of the isolated VEGF-C-cleaving activity from human saliva, we identified cathepsin D as a protease that can activate VEGF-C as well as VEGF-D. VL - 8 SN - 2050-084X UR - https://elifesciences.org/articles/44478 JO - eLife ER - TY - JOUR T1 - The Proteolytic Activation of Vascular Endothelial Growth Factor-C JF - Lymphologie in Forschung und Praxis Y1 - 2019 A1 - Lackner, Marcel A1 - Schmotz, Constanze A1 - Jeltsch, Michael KW - Lymphangiogenesis KW - proteinases KW - proteolysis KW - VEGF-C AB - The enzymatic cleavage of the protein backbone (proteolysis) is integral to many biological processes, e.g. for the break­down of proteins in the digestive system. Specific proteolytic cleavages are also used to turn on or off the activity of proteins. For example, the lymphangiogenic vascular endothelial growth factor-­C (VEGF-­C) is synthesized as a precursor molecule that must be converted to a mature form by the enzymatic removal of C-­ and N-­terminal propeptides before it can bind and activate its receptors. The constitutive C-­terminal cleavage is mediated by proprotein convertases such as furin. The subsequent ac­tivating cleavage can be mediated by at least four different proteases: by plasmin, ADAMTS3, prostate­-specific antigen (PSA) and cathepsin D. Processing by different proteases results in distinct forms of "ma­ture" VEGF­-C, that differ in their affinity and their receptor activation potential. This processing is tightly regulated by the CCBE1 protein. CCBE1 regulates the acti­vating cleavage of VEGF­C by ADAMTS3 and PSA, but not by plasmin. During embryonic development of the lymphatic system, VEGF-­C is activated primarily by the ADAMTS3 protease. In contrast, it is believed that plasmin is responsible for wound healing lymphangiogenesis and PSA for tumor-­associated pathological lym­phangiogenesis. Cathepsin D has also been implicated in tumor lymphangiogenesis. In addition, cathepsin D in saliva might activate latent VEGF­C upon wound licking, thereby accelerating wound healing. The molecular details of proteolytic activation of VEGF­-C are only recently extensively explored, and we likely do not know yet all activating proteases. It appears that the activity of VEGF­-C is regulated for different specific functions by different proteinases. Although VEGF­-C clearly plays a pivotal role for tumor progression and metastasis in experimental animal studies, the rele­vance of most correlative studies on the role of VEGF­-C in human cancers is quite limited until now, also due to the lack of methods to differentiate between inactive and active forms. VL - 23 UR - https://doi.org/10.5281/zenodo.3629263 IS - 2 JO - LymphForsch ER - TY - CONF T1 - What you should know about VEGF-C when working with lymphatics [German] T2 - Lymphologie 2017 Y1 - 2017 A1 - Jeltsch, Michael JF - Lymphologie 2017 CY - Bad Soden (Frankfurt), Germany UR - https://jeltsch.org/Abstrakt-BadSoden2017 ER - TY - JOUR T1 - Die lymphangiogenen Wachstumsfaktoren VEGF-C und VEGF-D JF - Lymphologie in Forschung und Praxis Y1 - 2013 A1 - Krebs, Rainer A1 - Jeltsch, Michael KW - Lymphangiogenese KW - VEGF-C KW - VEGF-D KW - Wachstumsfaktoren AB - VEGF-C und VEGF-D sind die zwei zentralen Signalmoleküle, die für die Entwicklung und das Wachstum des Lymphgefäßsystems verantwortlich sind. Beide gehören zur VEGF-Proteinfamilie, deren Mitglieder hauptsächlich im Wachstum von Blutgefässen (Angiogenese) und Lymphgefässen (Lymphangiogenese) ihre Funktionen haben. Die VEGF-Familie umfasst in Säugetieren fünf Mitglieder: VEGF, PlGF, VEGF-B, VEGF-C und VEGF-D. Benannt wurde diese Familie nach ihrem zuerst entdeckten Mitglied VEGF („Vascular Endothelial Growth Factor”). VEGF-C und VEGF-D bilden funktionell und strukturell eine Untergruppe innerhalb der VEGF-Familie. Sie unterscheiden sich von den anderen VEGFs durch ihre besondere Biosynthese: sie werden als inaktive Vorgängermoleküle produziert, für deren Aktivierung ihre langen N- und C-terminalen Propeptide enzymatisch abgespalten werden müssen. Im Gegensatz zu den anderen VEGFs sind VEGF-C und VEGF-D direkte Stimulatoren für das Wachstum lymphatischer Gefäße. Ihre lymphangiogene Wirkung enfalten VEGF-C und VEGF-D über den VEGF-Rezeptor-3 (VEGFR-3), der im erwachsenen Organismus fast nur auf den Endothelzellen der Lymphvaskulatur zu finden ist. In diesem Artikel geben wir einen Überblick über die VEGF-Proteinfamilie und deren Rezeptoren mit dem Schwerpunkt auf den lymphangiogenen Mitgliedern VEGF-C und VEGF-D, über ihre Biosynthese und ihre Rolle in der Embryonalentwicklung. VEGF-C and VEGF-D are the two central signaling molecules that stimulate the development and the growth of lymphatic system. Both belong to the VEGF protein family which plays important roles in the growth of blood vessels (angiogenesis) and lymphatic vessels (lymphangiogenesis). In mammals the VEGF family comprises five members: VEGF, PlGF, VEGF-B, VEGF-C and VEGF-D. The family was named after its first discovered member VEGF (“Vascular Endothelial Growth Factor”). VEGF-C and VEGF-D form functionally and structurally a subgroup within this family. They differ from the other VEGFs by their peculiar biosynthesis: they are produced as inactive precursors and need to be activated by proteolytic removal of their long N- and C-terminal propeptides. Unlike the other VEGFs, VEGF-C and VEGF-D are direct stimulators of lymphatic growth. They exert their lymphangiogenic function via VEGF receptor 3, which is expressed in the adult organism almost exclusively on lymphatic endothelial cells. In this review we give an overview of the VEGF protein family and their receptors with the emphasis on the lymphangiogenic VEGF-C and VEGF-D, and we discuss their biosynthesis and their role in embryonic lymphangiogenesis. VL - 17 IS - 1 ER - TY - JOUR T1 - Die lymphangiogenic growth factors VEGF-C and VEGF-D. Part 2: The role of VEGF-C and VEGF-D in diseases of the lymphatic system. [bilingual: English, German]. JF - Lymphologie in Forschung und Praxis Y1 - 2013 A1 - Krebs, Rainer A1 - Jeltsch, Michael KW - growth factors KW - Lymphangiogenesis KW - lymphedema KW - lymphogenic metastasis KW - VEGF-C KW - VEGF-D AB - VEGF-C and VEGF-D are the two central signaling molecules that stimulate the develop- ment and growth of the lymphatic system. Both belong to the vascular endothelial growth factor (VEGF) protein family, which plays important roles in the growth of blood vessels (angiogenesis) and lymphatic vessels (lymphangiogenesis). In mammals, the VEGF family comprises five members: VEGF-A, PlGF, VEGF-B, VEGF-C and VEGF-D. The family was named after VEGF-A, the first member to be discovered. VEGF-C and VEGF-D form a subgroup within this family in terms of function and structure. Their distinctive biosynthesis differentiates them from the other VEGFs: they are produced as inactive precursors and need to be activated by proteolytic removal of their long N- and C-terminal propeptides. Unlike the other VEGFs, VEGF-C and VEGF-D are direct stimulators of lymphatic vessel growth. They exert their lymphangiogenic function via VEGF receptor 3, which is expressed in the adult organism almost exclusively on lymphatic endothelial cells. In this review, we provide an overview of the VEGF protein family and their receptors. We focus on the lymphangiogenic VEGF-C and VEGF-D, discussing their biosynthesis and their role in embryonic lymphangiogenesis. VL - 17 UR - http://jeltsch.org/sites/jeltsch.org/files/JeltschMichael_Lymphforsch2013_96.pdf IS - 2 JO - Lymphforsch ER - TY - JOUR T1 - The lymphangiogenic growth factors VEGF-C and VEGF-D. Part 1: Basic principles and embryonic development. [bilingual: English, German]. JF - Lymphologie in Forschung und Praxis Y1 - 2013 A1 - Krebs, Rainer A1 - Jeltsch, Michael KW - growth factors KW - Lymphangiogenesis KW - VEGF-C KW - VEGF-D AB - VEGF-C and VEGF-D are the two central signaling molecules that stimulate the develop- ment and growth of the lymphatic system. Both belong to the vascular endothelial growth factor (VEGF) protein family, which plays important roles in the growth of blood vessels (angiogenesis) and lymphatic vessels (lymphangiogenesis). In mammals, the VEGF family comprises five members: VEGF-A, PlGF, VEGF-B, VEGF-C and VEGF-D. The family was named after VEGF-A, the first member to be discovered. VEGF-C and VEGF-D form a subgroup within this family in terms of function and structure. Their distinctive biosynthesis differentiates them from the other VEGFs: they are produced as inactive precursors and need to be activated by proteolytic removal of their long N- and C-terminal propeptides. Unlike the other VEGFs, VEGF-C and VEGF-D are direct stimulators of lymphatic vessel growth. They exert their lymphangiogenic function via VEGF receptor 3, which is expressed in the adult organism almost exclusively on lymphatic endothelial cells. In this review, we provide an overview of the VEGF protein family and their receptors. We focus on the lymphangiogenic VEGF-C and VEGF-D, discussing their biosynthesis and their role in embryonic lymphangiogenesis. VL - 17 UR - http://jeltsch.org/sites/jeltsch.org/files/JeltschMichael_Lymphforsch2013_30.pdf IS - 1 JO - Lymphforsch ER - TY - JOUR T1 - Structural determinants of vascular endothelial growth factor-D receptor binding and specificity JF - Blood Y1 - 2011 A1 - Leppänen, Veli-Matti A1 - Jeltsch, Michael A1 - Anisimov, Andrey A1 - Tvorogov, Denis A1 - Aho, Kukka A1 - Kalkkinen, Nisse A1 - Toivanen, Pyry A1 - Ylä-Herttuala, Seppo A1 - Ballmer-Hofer, Kurt A1 - Alitalo, Kari AB - Vascular endothelial growth factors (VEGFs) and their tyrosine kinase receptors (VEGFR-1-3) are central mediators of angiogenesis and lymphangiogenesis. VEGFR-3 ligands VEGF-C and VEGF-D are produced as precursor proteins with long N- and C-terminal propeptides and show enhanced VEGFR-2 and VEGFR-3 binding on proteolytic removal of the propeptides. Two different proteolytic cleavage sites have been reported in the VEGF-D N-terminus. We report here the crystal structure of the human VEGF-D Cys117Ala mutant at 2.9 Å resolution. Comparison of the VEGF-D and VEGF-C structures shows similar extended N-terminal helices, conserved overall folds, and VEGFR-2 interacting residues. Consistent with this, the affinity and the thermodynamic parameters for VEGFR-2 binding are very similar. In comparison with VEGF-C structures, however, the VEGF-D N-terminal helix was extended by 2 more turns because of a better resolution. Both receptor binding and functional assays of N-terminally truncated VEGF-D polypeptides indicated that the residues between the reported proteolytic cleavage sites are important for VEGF-D binding and activation of VEGFR-3, but not of VEGFR-2. Thus, we define here a VEGFR-2-specific form of VEGF-D that is angiogenic but not lymphangiogenic. These results provide important new insights into VEGF-D structure and function. VL - 117 UR - http://view.ncbi.nlm.nih.gov/pubmed/21148085 IS - 5 JO - Blood ER - TY - JOUR T1 - VEGF-C/VEGFR-3 Signaling Regulates Inflammatory Response in Development of Obliterative Airway Disease JF - Journal of Heart and Lung Transplantation Y1 - 2011 A1 - Krebs, R A1 - Tikkanen, JM A1 - Ropponen, JO A1 - Jeltsch, M A1 - Jokinen, JJ A1 - Ylä-Herttuala, S A1 - Koskinen, PK A1 - Nykänen, AI A1 - Lemström, KB VL - 30 ER - 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 - 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 - Structural determinants of growth factor binding and specificity by VEGF receptor 2 JF - Proceedings of the National Academy of Sciences of the United States of America Y1 - 2010 A1 - Leppänen, Veli-Matti A1 - Prota, Andrea E A1 - Jeltsch, Michael A1 - Anisimov, Andrey A1 - Kalkkinen, Nisse A1 - Strandin, Tomas A1 - Lankinen, Hilkka A1 - Goldman, Adrian A1 - Ballmer-Hofer, Kurt A1 - Alitalo, Kari AB - Vascular endothelial growth factors (VEGFs) regulate blood and lymph vessel formation through activation of three receptor tyrosine kinases, VEGFR-1, -2, and -3. The extracellular domain of VEGF receptors consists of seven immunoglobulin homology domains, which, upon ligand binding, promote receptor dimerization. Dimerization initiates transmembrane signaling, which activates the intracellular tyrosine kinase domain of the receptor. VEGF-C stimulates lymphangiogenesis and contributes to pathological angiogenesis via VEGFR-3. However, proteolytically processed VEGF-C also stimulates VEGFR-2, the predominant transducer of signals required for physiological and pathological angiogenesis. Here we present the crystal structure of VEGF-C bound to the VEGFR-2 high-affinity-binding site, which consists of immunoglobulin homology domains D2 and D3. This structure reveals a symmetrical 22 complex, in which left-handed twisted receptor domains wrap around the 2-fold axis of VEGF-C. In the VEGFs, receptor specificity is determined by an N-terminal alpha helix and three peptide loops. Our structure shows that two of these loops in VEGF-C bind to VEGFR-2 subdomains D2 and D3, while one interacts primarily with D3. Additionally, the N-terminal helix of VEGF-C interacts with D2, and the groove separating the two VEGF-C monomers binds to the D2/D3 linker. VEGF-C, unlike VEGF-A, does not bind VEGFR-1. We therefore created VEGFR-1/VEGFR-2 chimeric proteins to further study receptor specificity. This biochemical analysis, together with our structural data, defined VEGFR-2 residues critical for the binding of VEGF-A and VEGF-C. Our results provide significant insights into the structural features that determine the high affinity and specificity of VEGF/VEGFR interactions. VL - 107 UR - http://view.ncbi.nlm.nih.gov/pubmed/20145116 IS - 6 ER - TY - JOUR T1 - Suppressive effects of vascular endothelial growth factor-B on tumor growth in a mouse model of pancreatic neuroendocrine tumorigenesis JF - PLoS ONE Y1 - 2010 A1 - Albrecht, Imke A1 - Kopfstein, Lucie A1 - Strittmatter, Karin A1 - Schomber, Tibor A1 - Falkevall, Annelie A1 - Hagberg, Carolina E A1 - Lorentz, Pascal A1 - Jeltsch, Michael A1 - Alitalo, Kari A1 - Eriksson, Ulf A1 - Christofori, Gerhard A1 - Pietras, Kristian AB - BACKGROUND: The family of vascular endothelial growth factors (VEGF) contains key regulators of blood and lymph vessel development, including VEGF-A, -B, -C, -D, and placental growth factor. The role of VEGF-B during physiological or pathological angiogenesis has not yet been conclusively delineated. Herein, we investigate the function of VEGF-B by the generation of mouse models of cancer with transgenic expression of VEGF-B or homozygous deletion of Vegfb. METHODOLOGY/PRINCIPAL FINDINGS: Ectopic expression of VEGF-B in the insulin-producing β-cells of the pancreas did not alter the abundance or architecture of the islets of Langerhans. The vasculature from transgenic mice exhibited a dilated morphology, but was of similar density as that of wildtype mice. Unexpectedly, we found that transgenic expression of VEGF-B in the RIP1-Tag2 mouse model of pancreatic neuroendocrine tumorigenesis retarded tumor growth. Conversely, RIP1-Tag2 mice deficient for Vegfb presented with larger tumors. No differences in vascular density, perfusion or immune cell infiltration upon altered Vegfb gene dosage were noted. However, VEGF-B acted to increase blood vessel diameter both in normal pancreatic islets and in RIP1-Tag2 tumors. CONCLUSIONS/SIGNIFICANCE: Taken together, our results illustrate the differences in biological function between members of the VEGF family, and highlight the necessity of in-depth functional studies of VEGF-B to fully understand the effects of VEGFR-1 inhibitors currently used in the clinic. VL - 5 UR - http://view.ncbi.nlm.nih.gov/pubmed/21124841 IS - 11 JO - PLoS ONE 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 - Activated forms of VEGF-C and VEGF-D provide improved vascular function in skeletal muscle JF - Circ Res Y1 - 2009 A1 - Anisimov, Andrey A1 - Alitalo, Annamari A1 - Korpisalo, Petra A1 - Soronen, Jarkko A1 - Kaijalainen, Seppo A1 - Leppänen, Veli-Matti A1 - Jeltsch, Michael A1 - Ylä-Herttuala, Seppo A1 - Alitalo, Kari AB - The therapeutic potential of vascular endothelial growth factor (VEGF)-C and VEGF-D in skeletal muscle has been of considerable interest as these factors have both angiogenic and lymphangiogenic activities. Previous studies have mainly used adenoviral gene delivery for short-term expression of VEGF-C and VEGF-D in pig, rabbit, and mouse skeletal muscles. Here we have used the activated mature forms of VEGF-C and VEGF-D expressed via recombinant adeno-associated virus (rAAV), which provides stable, long-lasting transgene expression in various tissues including skeletal muscle. Mouse tibialis anterior muscle was transduced with rAAV encoding human or mouse VEGF-C or VEGF-D. Two weeks later, immunohistochemical analysis showed increased numbers of both blood and lymph vessels, and Doppler ultrasound analysis indicated increased blood vessel perfusion. The lymphatic vessels further increased at the 4-week time point were functional, as shown by FITC-lectin uptake and transport. Furthermore, receptor activation and arteriogenic activity were increased by an alanine substitution mutant of human VEGF-C (C137A) having an increased dimer stability and by a chimeric CAC growth factor that contained the VEGF receptor-binding domain flanked by VEGF-C propeptides, but only the latter promoted significantly more blood vessel perfusion when compared to the other growth factors studied. We conclude that long-term expression of VEGF-C and VEGF-D in skeletal muscle results in the generation of new functional blood and lymphatic vessels. The therapeutic value of intramuscular lymph vessels in draining tissue edema and lymphedema can now be evaluated using this model system. VL - 104 UR - http://view.ncbi.nlm.nih.gov/pubmed/19443835 IS - 11 JO - Circulation Research ER - TY - JOUR T1 - Overexpression of vascular endothelial growth factor-B in mouse heart alters cardiac lipid metabolism and induces myocardial hypertrophy JF - Circ Res Y1 - 2008 A1 - Karpanen, Terhi A1 - Bry, Maija A1 - Ollila, Hanna M A1 - Seppänen-Laakso, Tuulikki A1 - Liimatta, Erkki A1 - Leskinen, Hanna A1 - Kivelä, Riikka A1 - Helkamaa, Teemu A1 - Merentie, Mari A1 - Jeltsch, Michael A1 - Paavonen, Karri A1 - Andersson, Leif C A1 - Mervaala, Eero A1 - Hassinen, Ilmo E A1 - Ylä-Herttuala, Seppo A1 - Oresic, Matej A1 - Alitalo, Kari AB - Vascular endothelial growth factor (VEGF)-B is poorly angiogenic but prominently expressed in metabolically highly active tissues, including the heart. We produced mice expressing a cardiac-specific VEGF-B transgene via the alpha-myosin heavy chain promoter. Surprisingly, the hearts of the VEGF-B transgenic mice showed concentric cardiac hypertrophy without significant changes in heart function. The cardiac hypertrophy was attributable to an increased size of the cardiomyocytes. Blood capillary size was increased, whereas the number of blood vessels per cell nucleus remained unchanged. Despite the cardiac hypertrophy, the transgenic mice had lower heart rate and blood pressure than their littermates, and they responded similarly to angiotensin II-induced hypertension, confirming that the hypertrophy does not compromise heart function. Interestingly, the isolated transgenic hearts had less cardiomyocyte damage after ischemia. Significantly increased ceramide and decreased triglyceride levels were found in the transgenic hearts. This was associated with structural changes and eventual lysis of mitochondria, resulting in accumulation of intracellular vacuoles in cardiomyocytes and increased death of the transgenic mice, apparently because of mitochondrial lipotoxicity in the heart. These results suggest that VEGF-B regulates lipid metabolism, an unexpected function for an angiogenic growth factor. VL - 103 UR - http://view.ncbi.nlm.nih.gov/pubmed/18757827 IS - 9 JO - Circulation Research 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 - The tyrosine kinase inhibitor cediranib blocks ligand-induced vascular endothelial growth factor receptor-3 activity and lymphangiogenesis JF - Cancer Res Y1 - 2008 A1 - Heckman, Caroline A A1 - Holopainen, Tanja A1 - Wirzenius, Maria A1 - Keskitalo, Salla A1 - Jeltsch, Michael A1 - Ylä-Herttuala, Seppo A1 - Wedge, Stephen R A1 - Jürgensmeier, Juliane M A1 - Alitalo, Kari AB - Solid tumors express a range of factors required to sustain their growth and promote their dissemination. Among these are vascular endothelial growth factor-A (VEGF-A), the key angiogenic stimulant, and VEGF-C, a primary mediator of lymphangiogenesis. Small molecule tyrosine kinase inhibitors offer the potential to inhibit more than one kinase and impede tumor growth by multiple mechanisms. However, their potency toward individual targets can vary. Cediranib (RECENTIN; AZD2171) is an inhibitor of VEGF signaling that has been shown in experimental models to prevent VEGF-A-induced angiogenesis and primary tumor growth, yet the effects of cediranib on VEGF receptor (VEGFR)-3-mediated endothelial cell function and lymphangiogenesis are unknown. To better understand the activity of cediranib against VEGFR-3 and its associated signaling events compared with its activity against VEGFR-2, we used the receptor-specific ligands VEGF-E and VEGF-C156S. In human endothelial cells, cediranib inhibited VEGF-E-induced phosphorylation of VEGFR-2 and VEGF-C156S-induced phosphorylation of VEGFR-3 at concentrations of