@article {701, title = {Investigation on the role of biallelic variants in VEGF-C found in a patient affected by Milroy-like lymphedema}, journal = {Molecular Genetics \& Genomic Medicine}, volume = {00}, year = {2020}, month = {Feb-06-2022}, pages = {e1389}, issn = {2324-9269}, doi = {10.1002/mgg3.1389}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mgg3.1389}, author = {Mukenge, Sylvain and Jha, Sawan K. and Catena, Marco and Manara, Elena and Lepp{\"a}nen, Veli-Matti and Lenti, Elisa and Negrini, Daniela and Bertelli, Matteo and Brendolan, Andrea and Jeltsch, Michael and Aldrighetti, Luca} } @article {694, title = {Lymphatics and the eye. [Finnish]}, journal = {Duodecim L{\"a}{\"a}ketieteellinen Aikakauskirja}, volume = {136}, year = {2020}, month = {2020/02/10/}, pages = {1777-1788}, type = {review}, chapter = {1777}, issn = {2242-3281}, doi = {10.5281/zenodo.4005517}, url = {https://www.duodecimlehti.fi/lehti/2020/16/duo15739}, author = {Gucciardo, Erika and Lehti, Timo A. and Korhonen, Ani and Salv{\'e}n, Petri and Lehti, Kaisa and Jeltsch, Michael and Loukovaara, Sirpa} } @article {708, title = {VEGF-C Protects the Integrity of Bone Marrow Perivascular Niche}, journal = {Blood}, year = {2020}, month = {2020/07/31/}, pages = {accepted - for publication}, abstract = {Key Points. Vegfc deletion in endothelial or LepR+ cells compromises the bone marrow perivascular niche and hematopoietic stem cell maintenance.Exogenous admin}, doi = {10.1182/blood.2020005699}, url = {https://ashpublications.org/blood/article/doi/10.1182/blood.2020005699/463465/VEGF-C-Protects-the-Integrity-of-Bone-Marrow}, author = {Fang, Shentong and Chen, Shuo and Nurmi, Harri and Lepp{\"a}nen, Veli-Matti and Jeltsch, Michael and Scadden, David T. and Silberstein, Lev and Mikkola, Hanna and Alitalo, Kari} } @article {690, title = {The Proteolytic Activation of Vascular Endothelial Growth Factor-C}, journal = {Lymphologie in Forschung und Praxis}, volume = {23}, year = {2019}, month = {2019/12/18/}, pages = {88 - 98}, type = {Review}, abstract = {The enzymatic cleavage of the protein backbone (proteolysis) is integral to many biological processes, e.g. for the break-down 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 ac-tivating 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 "ma-ture" VEGF--C, that differ in their affinity and their receptor activation potential. This processing is tightly regulated by the CCBE1 protein. CCBE1 regulates the acti-vating cleavage of VEGF-C 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 lym-phangiogenesis. Cathepsin D has also been implicated in tumor lymphangiogenesis. In addition, cathepsin D in saliva might activate latent VEGF-C 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 rele-vance 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.}, keywords = {Lymphangiogenesis, proteinases, proteolysis, VEGF-C}, doi = {10.5281/zenodo.3629263}, url = {https://doi.org/10.5281/zenodo.3629263}, author = {Lackner, Marcel and Schmotz, Constanze and Jeltsch, Michael} } @article {589, title = {Efficient activation of the lymphangiogenic growth factor VEGF-C requires the C-terminal domain of VEGF-C and the N-terminal domain of CCBE1}, journal = {Scientific Reports}, volume = {7}, year = {2017}, month = {2017/07/07/}, pages = {4916}, doi = {10.1038/s41598-017-04982-1}, url = {https://www.nature.com/articles/s41598-017-04982-1}, author = {Jha, SK and Rauniyar, Khushbu and K{\"a}rp{\"a}nen, Terhi and Lepp{\"a}nen, Veli-Matti and Brouillard, Pascal and Vikkula, Miikka and Alitalo, Kari and Jeltsch, Michael} } @article {502, title = {Functional Dissection of the CCBE1 Protein: A Crucial Requirement for the Collagen Repeat Domain.}, journal = {Circ Res}, volume = {116}, year = {2015}, month = {2015 May 8}, pages = {1660-1669}, abstract = {

RATIONALE: Collagen- and calcium-binding EGF domain-containing protein 1 (CCBE1) is essential for lymphangiogenesis in vertebrates and has been associated with Hennekam syndrome. Recently, CCBE1 has emerged as a crucial regulator of vascular endothelial growth factor-C (VEGFC) signaling.

OBJECTIVE: CCBE1 is a secreted protein characterized by 2 EGF domains and 2 collagen repeats. The functional role of the different CCBE1 protein domains is completely unknown. Here, we analyzed the functional role of the different CCBE1 domains in vivo and in vitro.

METHODS AND RESULTS: We analyzed the functionality of several CCBE1 deletion mutants by generating knock-in mice expressing these mutants, by analyzing their ability to enhance Vegfc signaling in vivo in zebrafish, and by testing their ability to induce VEGFC processing in vitro. We found that deleting the collagen domains of CCBE1 has a much stronger effect on CCBE1 activity than deleting the EGF domains. First, although CCBE1ΔCollagen mice fully phenocopy CCBE1 knock-out mice, CCBE1ΔEGF knock-in embryos still form rudimentary lymphatics. Second, Ccbe1ΔEGF, but not Ccbe1ΔCollagen, could partially substitute for Ccbe1 to enhance Vegfc signaling in zebrafish. Third, CCBE1ΔEGF, similarly to CCBE1, but not CCBE1ΔCollagen could activate VEGFC processing in vitro. Furthermore, a Hennekam syndrome mutation within the collagen domain has a stronger effect than a Hennekam syndrome mutation within the EGF domain.

CONCLUSIONS: We propose that the collagen domains of CCBE1 are crucial for the activation of VEGFC in vitro and in vivo. The EGF domains of CCBE1 are dispensable for regulation of VEGFC processing in vitro, however, they are necessary for full lymphangiogenic activity of CCBE1 in vivo.

}, keywords = {Animals, Binding Sites, Calcium-Binding Proteins, Collagen, Craniofacial Abnormalities, Endothelial Cells, Epidermal Growth Factor, Gene Expression Regulation, Developmental, Gene Knock-In Techniques, Genital Diseases, Male, Genotype, Gestational Age, HEK293 Cells, Humans, Lymphangiectasis, Intestinal, Lymphatic Vessels, lymphedema, Mice, Mice, Transgenic, Mutation, Phenotype, Protein Binding, Protein Interaction Domains and Motifs, Signal Transduction, Transfection, Tumor Suppressor Proteins, Vascular Endothelial Growth Factor C, Zebrafish, Zebrafish Proteins}, issn = {1524-4571}, doi = {10.1161/CIRCRESAHA.116.304949}, url = {http://circres.ahajournals.org/content/116/10/1660.long}, author = {Roukens, M Guy and Peterson-Maduro, Josi and Padberg, Yvonne and Jeltsch, Michael and Lepp{\"a}nen, Veli-Matti and Bos, Frank L and Alitalo, Kari and Schulte-Merker, Stefan and Schulte, D{\"o}rte} } @article {505, title = {Ischemia-Reperfusion Injury Enhances Lymphatic Endothelial VEGFR3 and Rejection in Cardiac Allografts}, journal = {American Journal of Transplantation}, volume = {16}, year = {2015}, month = {12/2015}, pages = {1160-1172}, abstract = {Organ damage and innate immunity during heart transplantation may evoke adaptive immunity with serious consequences. Because lymphatic vessels bridge innate and adaptive immunity, they are critical in immune surveillance; however, their role in ischemia{\textendash}reperfusion injury (IRI) in allotransplantation remains unknown. We investigated whether the lymphangiogenic VEGF-C/VEGFR3 pathway during cardiac allograft IRI regulates organ damage and subsequent interplay between innate and adaptive immunity. We found that cardiac allograft IRI, within hours, increased graft VEGF-C expression and lymphatic vessel activation in the form of increased lymphatic VEGFR3 and adhesion protein expression. Pharmacological VEGF-C/VEGFR3 stimulation resulted in early lymphatic activation and later increase in allograft inflammation. In contrast, pharmacological VEGF-C/VEGFR3 inhibition during cardiac allograft IRI decreased early lymphatic vessel activation with subsequent dampening of acute and chronic rejection. Genetic deletion of VEGFR3 specifically in the lymphatics of the transplanted heart recapitulated the survival effect achieved by pharmacological VEGF-C/VEGFR3 inhibition. Our results suggest that tissue damage rapidly changes lymphatic vessel phenotype, which, in turn, may shape the interplay of innate and adaptive immunity. Importantly, VEGF-C/VEGFR3 inhibition during solid organ transplant IRI could be used as lymphatic-targeted immunomodulatory therapy to prevent acute and chronic rejection.}, doi = {10.1111/ajt.13564}, url = {http://onlinelibrary.wiley.com/doi/10.1111/ajt.13564/abstract}, author = {Dashkevich, A. and Raissadati, A. and Syrj{\"a}l{\"a}, S. O. and Zarkada, G. and Ker{\"a}nen, M. A. I. and Tuuminen, R. and Krebs, R. and Anisimov, A. and Jeltsch, M. and Lepp{\"a}nen, V.-M. and Alitalo, K. and Nyk{\"a}nen, A. I. and Lemstr{\"o}m, K. B.} } @inbook {503, title = {The TIE Receptor Family}, booktitle = {Receptor Tyrosine Kinases: Family and Subfamilies}, year = {2015}, pages = {743-775}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, chapter = {16}, keywords = {ANG, Angiopoietin, ANGPT, Endothelial cell, Lymphatic vessel, Neovascularization, TIE1, TIE2, Vascular dysfunction}, issn = {978-3-319-11888-8}, doi = {10.1007/978-3-319-11888-8_16}, url = {https://link.springer.com/content/pdf/10.1007\%2F978-3-319-11888-8_16.pdf}, author = {Saharinen, Pipsa and Jeltsch, Michael and Santoyo, MayteM. and Lepp{\"a}nen, Veli-Matti and Alitalo, Kari}, editor = {Wheeler, Deric L. and Yarden, Yosef} } @article {441, title = {CCBE1 enhances lymphangiogenesis via ADAMTS3-mediated VEGF-C activation}, journal = {Circulation}, volume = {129}, year = {2014}, month = {05/2014}, chapter = {1962-1971}, abstract = {Background{\textemdash}Hennekam lymphangiectasia-lymphedema syndrome (OMIM 235510) is a rare autosomal recessive disease, which is associated with mutations in the collagen- and calcium-binding EGF domains 1 (CCBE1) gene. Because of the striking phenotypic similarity of embryos lacking either the Ccbe1 gene or the lymphangiogenic growth factor Vegfc gene, we searched for CCBE1 interactions with the VEGF-C growth factor signaling pathway, which is critical in embryonic and adult lymphangiogenesis. Methods and Results{\textemdash}By analyzing VEGF-C produced by CCBE1-transfected cells, we found that while CCBE1 itself does not process VEGF-C, it promotes proteolytic cleavage of the otherwise poorly active 29/31-kDa form of VEGF-C by the A disintegrin and metalloprotease with thrombospondin motifs-3 (ADAMTS3) protease, resulting in the mature 21/23-kDa form of VEGF-C, which induces increased VEGF-C receptor signaling. Adeno-associated viral vector (AAV) mediated transduction of CCBE1 into mouse skeletal muscle enhanced lymphangiogenesis and angiogenesis induced by AAV-VEGF-C. Conclusions{\textemdash}These results identify ADAMTS3 as a VEGF-C activating protease and reveal a novel type of regulation of a vascular growth factor by a protein that enhances its proteolytic cleavage and activation. The results suggest CCBE1 is a potential therapeutic tool for the modulation of lymphangiogenesis and angiogenesis in a variety of diseases that involve the lymphatic system, such as lymphedema or lymphatic metastasis.}, keywords = {ADAMTS3, angiogenesis, CCBE1, endothelium, growth factors and cytokines, Hennekam Syndrome, metalloproteinase, vasculature, VEGF-C}, doi = {http://dx.doi.org/10.1161/CIRCULATIONAHA.113.002779}, url = {http://circ.ahajournals.org/content/early/2014/02/19/CIRCULATIONAHA.113.002779.abstract}, author = {Jeltsch, Michael and Jha, Sawan Kumar and Tvorogov, Denis and Anisimov, Andrey and Lepp{\"a}nen, Veli-Matti and Holopainen, Tanja and Kivel{\"a}, Riikka and Ortega, Sagrario and K{\"a}rp{\"a}nen, Terhi and Alitalo, Kari} } @article {426, title = {The basis for the distinct biological activities of vascular endothelial growth factor receptor-1 ligands}, journal = {Sci Signal}, volume = {6}, year = {2013}, month = {2013}, pages = {ra52}, abstract = {

Vascular endothelial growth factors (VEGFs) regulate blood and lymphatic vessel development through VEGF receptors (VEGFRs). The VEGFR immunoglobulin homology domain 2 (D2) is critical for ligand binding, and D3 provides additional interaction sites. VEGF-B and placenta growth factor (PlGF) bind to VEGFR-1 with high affinity, but only PlGF is angiogenic in most tissues. We show that VEGF-B, unlike other VEGFs, did not require D3 interactions for high-affinity binding. VEGF-B with a PlGF-derived L1 loop (B-L1(P)) stimulated VEGFR-1 activity, whereas PlGF with a VEGF-B-derived L1 loop (P-L1(B)) did not. Unlike P-L1(B) and VEGF-B, B-L1(P) and PlGF were also angiogenic in mouse skeletal muscle. Furthermore, B-L1(P) also bound to VEGFR-2 and activated downstream signaling. These results establish a role for L1-mediated D3 interactions in VEGFR activation in endothelial cells and indicate that VEGF-B is a high-affinity VEGFR-1 ligand that, unlike PlGF, cannot efficiently induce signaling downstream of VEGFR-1.

}, keywords = {PlGF, receptor tyrosine kinase, Signal Transduction, VEGF-B, VEGFR-1}, issn = {1937-9145}, doi = {10.1126/scisignal.2003905}, author = {Anisimov, Andrey and Lepp{\"a}nen, Veli-Matti and Tvorogov, Denis and Zarkada, Georgia and Jeltsch, Michael and Holopainen, Tanja and Kaijalainen, Seppo and Alitalo, Kari} } @article {445, title = {Receptor Tyrosine Kinase-Mediated Angiogenesis}, journal = {Cold Spring Harbor Perspectives in Biology}, volume = {5}, year = {2013}, month = {2013}, abstract = {The endothelial cell is the essential cell type forming the inner layer of the vasculature. Two families of receptor tyrosine kinases (RTKs) are almost completely endothelial cell specific: the vascular endothelial growth factor (VEGF) receptors (VEGFR1-3) and the Tie receptors (Tie1 and Tie2). Both are key players governing the generation of blood and lymphatic vessels during embryonic development. Because the growth of new blood and lymphatic vessels (or the lack thereof) is a central element in many diseases, the VEGF and the Tie receptors provide attractive therapeutic targets in various diseases. Indeed, several drugs directed to these RTK signaling pathways are already on the market, whereas many are in clinical trials. Here we review the VEGFR and Tie families, their involvement in developmental and pathological angiogenesis, and the different possibilities for targeting them to either block or enhance angiogenesis and lymphangiogenesis.}, isbn = {, 1943-0264}, doi = {10.1101/cshperspect.a009183}, url = {http://cshperspectives.cshlp.org/content/5/9/a009183}, author = {Jeltsch, Michael and Lepp{\"a}nen, Veli-Matti and Saharinen, Pipsa and Alitalo, Kari} } @article {442, title = {Structural and mechanistic insights into VEGF receptor 3 ligand binding and activation}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {110}, year = {2013}, month = {08/2013}, pages = {12960 - 12965}, abstract = {Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key drivers of blood and lymph vessel formation in development, but also in several pathological processes. VEGF-C signaling through VEGFR-3 promotes lymphangiogenesis, which is a clinically relevant target for treating lymphatic insufficiency and for blocking tumor angiogenesis and metastasis. The extracellular domain of VEGFRs consists of seven Ig homology domains; domains 1-3 (D1-3) are responsible for ligand binding, and the membrane-proximal domains 4-7 (D4-7) are involved in structural rearrangements essential for receptor dimerization and activation. Here we analyzed the crystal structures of VEGF-C in complex with VEGFR-3 domains D1-2 and of the VEGFR-3 D4-5 homodimer. The structures revealed a conserved ligand-binding interface in D2 and a unique mechanism for VEGFR dimerization and activation, with homotypic interactions in D5. Mutation of the conserved residues mediating the D5 interaction (Thr446 and Lys516) and the D7 interaction (Arg737) compromised VEGF-C induced VEGFR-3 activation. A thermodynamic analysis of VEGFR-3 deletion mutants showed that D3, D4-5, and D6-7 all contribute to ligand binding. A structural model of the VEGF-C/VEGFR-3 D1-7 complex derived from small-angle X-ray scattering data is consistent with the homotypic interactions in D5 and D7. Taken together, our data show that ligand-dependent homotypic interactions in D5 and D7 are essential for VEGFR activation, opening promising possibilities for the design of VEGFR-specific drugs.}, keywords = {Amino Acid Sequence, Binding Sites, Binding, Competitive, Crystallography, X-Ray, Electrophoresis, Polyacrylamide Gel, Humans, Ligands, Microscopy, Electron, Models, Molecular, Molecular Sequence Data, Multiprotein Complexes, Mutation, Protein Binding, Protein Multimerization, Protein Structure, Tertiary, Scattering, Small Angle, Sequence Homology, Amino Acid, Thermodynamics, Vascular Endothelial Growth Factor C, Vascular Endothelial Growth Factor Receptor-3, X-Ray Diffraction}, isbn = {1091-6490}, doi = {10.1073/pnas.1301415110}, url = {http://www.pnas.org/content/110/32/12960.long}, author = {Lepp{\"a}nen, Veli-Matti and Tvorogov, Denis and Kisko, Kaisa and Prota, Andrea E and Jeltsch, Michael and Anisimov, Andrey and Markovic-Mueller, Sandra and Stuttfeld, Edward and Goldie, Kenneth N and Ballmer-Hofer, Kurt and Alitalo, Kari} } @article {425, title = {A truncation allele in vascular endothelial growth factor c reveals distinct modes of signaling during lymphatic and vascular development.}, journal = {Development}, volume = {140}, year = {2013}, month = {2013 Apr}, pages = {1497-506}, abstract = {

Vascular endothelial growth factor C (Vegfc) is a secreted protein that guides lymphatic development in vertebrate embryos. However, its role during developmental angiogenesis is not well characterized. Here, we identify a mutation in zebrafish vegfc that severely affects lymphatic development and leads to angiogenesis defects on sensitized genetic backgrounds. The um18 mutation prematurely truncated Vegfc, blocking its secretion and paracrine activity but not its ability to activate its receptor Flt4. When expressed in endothelial cells, vegfc(um18) could not rescue lymphatic defects in mutant embryos, but induced ectopic blood vessel branching. Furthermore, vegfc-deficient endothelial cells did not efficiently contribute to tip cell positions in developing sprouts. Computational modeling together with assessment of endothelial cell dynamics by time-lapse analysis suggested that an autocrine Vegfc/Flt4 loop plays an important role in migratory persistence and filopodia stability during sprouting. Our results suggest that Vegfc acts in two distinct modes during development: as a paracrine factor secreted from arteries to guide closely associated lymphatic vasculature and as an autocrine factor to drive migratory persistence during angiogenesis.

}, keywords = {Alleles, Animals, Animals, Genetically Modified, Autocrine Communication, Blood Vessels, Cell Movement, Codon, Nonsense, Embryo, Nonmammalian, Female, Lymphatic System, Mice, Mice, Knockout, Neovascularization, Physiologic, Paracrine Communication, Protein Isoforms, Signal Transduction, Vascular Endothelial Growth Factor C, Zebrafish, Zebrafish Proteins}, issn = {1477-9129}, doi = {10.1242/dev.084152}, author = {Villefranc, Jacques A and Nicoli, Stefania and Bentley, Katie and Jeltsch, Michael and Zarkada, Georgia and Moore, John C and Gerhardt, Holger and Alitalo, Kari and Lawson, Nathan D} } @article {424, title = {Vascular endothelial growth factor-angiopoietin chimera with improved properties for therapeutic angiogenesis}, journal = {Circulation}, volume = {127}, year = {2013}, month = {01/2013}, pages = {424-434}, chapter = {424}, abstract = {BACKGROUND: There is an unmet need for proangiogenic therapeutic molecules for the treatment of tissue ischemia in cardiovascular diseases. However, major inducers of angiogenesis such as vascular endothelial growth factor (VEGF/VEGF-A) have side effects that limit their therapeutic utility in vivo, especially at high concentrations. Angiopoietin-1 has been considered to be a blood vessel stabilization factor that can inhibit the intrinsic property of VEGF to promote vessel leakiness. In this study, we have designed and tested the angiogenic properties of chimeric molecules consisting of receptor-binding parts of VEGF and angiopoietin-1. We aimed at combining the activities of both factors into 1 molecule for easy delivery and expression in target tissues. METHODS AND RESULTS: The VEGF-angiopoietin-1 (VA1) chimeric protein bound to both VEGF receptor-2 and Tie2 and induced the activation of both receptors. Detailed analysis of VA1 versus VEGF revealed differences in the kinetics of VEGF receptor-2 activation and endocytosis, downstream kinase activation, and VE-cadherin internalization. The delivery of a VA1 transgene into mouse skeletal muscle led to increased blood flow and enhanced angiogenesis. VA1 was also very efficient in rescuing ischemic limb perfusion. However, VA1 induced less plasma protein leakage and myeloid inflammatory cell recruitment than VEGF. Furthermore, angioma-like structures associated with VEGF expression were not observed with VA1. CONCLUSIONS: The VEGF-angiopoietin-1 chimera is a potent angiogenic factor that triggers a novel mode of VEGF receptor-2 activation, promoting less vessel leakiness, less tissue inflammation, and better perfusion in ischemic muscle than VEGF. These properties of VA1 make it an attractive therapeutic tool.}, author = {Andrey Anisimov and Denis Tvorogov and Annamari Alitalo and Veli-Matti Lepp{\"a}nen and Y An and EC Han and F Orsenigo and EI Ga{\'a}l and Tanja Holopainen and YJ Koh and Tuomas Tammela and P Korpisalo and Salla Keskitalo and Michael Jeltsch and Seppo Yl{\"a}-Herttuala and Elisabetta Dejana and GY Koh and C Choi and Pipsa Saharinen and Kari Alitalo} } @article {427, title = {Critical role of VEGF-C/VEGFR-3 signaling in innate and adaptive immune responses in experimental obliterative bronchiolitis.}, journal = {Am J Pathol}, volume = {181}, year = {2012}, month = {2012 Nov}, pages = {1607-20}, abstract = {

Chronic inflammation, a hallmark of obliterative bronchiolitis, is known to induce lymphangiogenesis. We therefore studied the role of lymphangiogenic vascular endothelial growth factor C (VEGF-C), its receptor VEGFR-3, and lymphangiogenesis during development of experimental obliterative bronchiolitis [ie, obliterative airway disease (OAD)] in rat tracheal allografts. The functional importance of VEGF-C was investigated by adenovirus-mediated overexpression of VEGF-C (AdVEGF-C), and by inhibition of VEGF-C activity with VEGFR-3-Ig (AdVEGFR-3-Ig). Analyses included histology, immunohistochemistry, and real-time RT-PCR 10 and 30 days after transplantation. In the course of OAD development, lymphangiogenesis was induced in the airway wall during the alloimmune response, which was reversed by cyclosporine A in a dose-dependent fashion. VEGF-C overexpression in tracheal allografts induced epithelial activation, neutrophil chemotaxis, and a shift toward a Th17 adaptive immune response, followed by enhanced lymphangiogenesis and the development of OAD. In contrast, inhibition of VEGF-C activity with VEGFR-3-Ig inhibited lymphangiogenesis and angiogenesis and reduced infiltration of CD4(+) T cells and the development of OAD. Lymphangiogenesis was linked to T-cell responses during the development of OAD, and VEGF-C/VEGFR-3 signaling modulated innate and adaptive immune responses in the development of OAD in rat tracheal allografts. Our results thus suggest VEGFR-3-signaling as a novel strategy to regulate T-cell responses in the development of obliterative bronchiolitis after lung transplantation.

}, keywords = {Adaptive Immunity, Animals, Bronchiolitis Obliterans, Chemotaxis, Cyclosporine, Dendritic Cells, Dose-Response Relationship, Drug, Down-Regulation, Epithelial Cells, Epithelium, Graft Rejection, Immunity, Innate, Immunoglobulins, Inflammation, Lymphangiogenesis, Macrophages, Neutrophils, Rats, Signal Transduction, Th17 Cells, Trachea, Transplantation, Homologous, Up-Regulation, Vascular Endothelial Growth Factor C, Vascular Endothelial Growth Factor Receptor-3}, issn = {1525-2191}, doi = {10.1016/j.ajpath.2012.07.021}, author = {Krebs, Rainer and Tikkanen, Jussi M and Ropponen, Jussi O and Jeltsch, Michael and Jokinen, Janne J and Yl{\"a}-Herttuala, Seppo and Nyk{\"a}nen, Antti I and Lemstr{\"o}m, Karl B} } @article {45, title = {Structural determinants of vascular endothelial growth factor-D receptor binding and specificity}, journal = {Blood}, volume = {117}, year = {2011}, month = {2011/Feb/}, pages = {1507 - 15}, abstract = {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 {\r A} 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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/21148085}, author = {Lepp{\"a}nen, Veli-Matti and Jeltsch, Michael and Anisimov, Andrey and Tvorogov, Denis and Aho, Kukka and Kalkkinen, Nisse and Toivanen, Pyry and Yl{\"a}-Herttuala, Seppo and Ballmer-Hofer, Kurt and Alitalo, Kari} } @article {44, title = {VEGF-C/VEGFR-3 Signaling Regulates Inflammatory Response in Development of Obliterative Airway Disease}, journal = {Journal of Heart and Lung Transplantation}, volume = {30}, year = {2011}, month = {2011//}, pages = {S118 - S118}, author = {Krebs, R and Tikkanen, JM and Ropponen, JO and Jeltsch, M and Jokinen, JJ and Yl{\"a}-Herttuala, S and Koskinen, PK and Nyk{\"a}nen, AI and Lemstr{\"o}m, KB} } @article {39, title = {Claudin-like protein 24 interacts with the VEGFR-2 and VEGFR-3 pathways and regulates lymphatic vessel development}, journal = {Genes Dev}, volume = {24}, year = {2010}, month = {2010/May/}, pages = {875 - 80}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/20439428}, author = {Saharinen, Pipsa and Helotera, Hanna and Miettinen, Juho and Norrmen, Camilla and D{\textquoteright}Amico, Gabriela and Jeltsch, Michael and Langenberg, Tobias and Vandevelde, Wouter and Ny, Annelii and Dewerchin, Mieke and Carmeliet, Peter and Alitalo, Kari} } @article {42, title = {Effective suppression of vascular network formation by combination of antibodies blocking VEGFR ligand binding and receptor dimerization}, journal = {Cancer Cell}, volume = {18}, year = {2010}, month = {2010/Dec/}, pages = {630 - 40}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/21130043}, author = {Tvorogov, Denis and Anisimov, Andrey and Zheng, Wei and Lepp{\"a}nen, Veli-Matti and Tammela, Tuomas and Laurinavicius, Simonas and Holnthoner, Wolfgang and Heloter{\"a}, Hanna and Holopainen, Tanja and Jeltsch, Michael and Kalkkinen, Nisse and Lankinen, Hilkka and Ojala, P{\"a}ivi M and Alitalo, Kari} } @article {40, title = {Structural determinants of growth factor binding and specificity by VEGF receptor 2}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {107}, year = {2010}, month = {02/2010}, pages = {2425 - 30}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/20145116}, author = {Lepp{\"a}nen, Veli-Matti and Prota, Andrea E and Jeltsch, Michael and Anisimov, Andrey and Kalkkinen, Nisse and Strandin, Tomas and Lankinen, Hilkka and Goldman, Adrian and Ballmer-Hofer, Kurt and Alitalo, Kari} } @article {41, title = {Suppressive effects of vascular endothelial growth factor-B on tumor growth in a mouse model of pancreatic neuroendocrine tumorigenesis}, journal = {PLoS ONE}, volume = {5}, year = {2010}, month = {2010//}, pages = {e14109}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/21124841}, author = {Albrecht, Imke and Kopfstein, Lucie and Strittmatter, Karin and Schomber, Tibor and Falkevall, Annelie and Hagberg, Carolina E and Lorentz, Pascal and Jeltsch, Michael and Alitalo, Kari and Eriksson, Ulf and Christofori, Gerhard and Pietras, Kristian} } @article {43, title = {Vascular endothelial growth factor-B acts as a coronary growth factor in transgenic rats without inducing angiogenesis, vascular leak, or inflammation}, journal = {Circulation}, volume = {122}, year = {2010}, month = {2010/Oct/}, pages = {1725 - 33}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/20937974}, author = {Bry, Maija and Kivel{\"a}, Riikka and Holopainen, Tanja and Anisimov, Andrey and Tammela, Tuomas and Soronen, Jarkko and Silvola, Johanna and Saraste, Antti and Jeltsch, Michael and Korpisalo, Petra and Carmeliet, Peter and Lemstr{\"o}m, Karl B and Shibuya, Masabumi and Yl{\"a}-Herttuala, Seppo and Alhonen, Leena and Mervaala, Eero and Andersson, Leif C and Knuuti, Juhani and Alitalo, Kari} } @article {38, title = {Activated forms of VEGF-C and VEGF-D provide improved vascular function in skeletal muscle}, journal = {Circ Res}, volume = {104}, year = {2009}, month = {2009/Jun/}, pages = {1302 - 12}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/19443835}, author = {Anisimov, Andrey and Alitalo, Annamari and Korpisalo, Petra and Soronen, Jarkko and Kaijalainen, Seppo and Lepp{\"a}nen, Veli-Matti and Jeltsch, Michael and Yl{\"a}-Herttuala, Seppo and Alitalo, Kari} } @article {37, title = {Overexpression of vascular endothelial growth factor-B in mouse heart alters cardiac lipid metabolism and induces myocardial hypertrophy}, journal = {Circ Res}, volume = {103}, year = {2008}, month = {2008/Oct/}, pages = {1018 - 26}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/18757827}, author = {Karpanen, Terhi and Bry, Maija and Ollila, Hanna M and Sepp{\"a}nen-Laakso, Tuulikki and Liimatta, Erkki and Leskinen, Hanna and Kivel{\"a}, Riikka and Helkamaa, Teemu and Merentie, Mari and Jeltsch, Michael and Paavonen, Karri and Andersson, Leif C and Mervaala, Eero and Hassinen, Ilmo E and Yl{\"a}-Herttuala, Seppo and Oresic, Matej and Alitalo, Kari} } @article {36, title = {Reevaluation of the role of VEGF-B suggests a restricted role in the revascularization of the ischemic myocardium}, journal = {Arterioscler Thromb Vasc Biol}, volume = {28}, year = {2008}, month = {2008/Sep/}, pages = {1614 - 20}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/18511699}, author = {Li, Xuri and Tjwa, Marc and Van Hove, Inge and Enholm, Berndt and Neven, Elke and Paavonen, Karri and Jeltsch, Michael and Juan, Toni Diez and Sievers, Richard E and Chorianopoulos, Emmanuel and Wada, Hiromichi and Vanwildemeersch, Maarten and Noel, Agnes and Foidart, Jean-Michel and Springer, Matthew L and von Degenfeld, Georges and Dewerchin, Mieke and Blau, Helen M and Alitalo, Kari and Eriksson, Ulf and Carmeliet, Peter and Moons, Lieve} } @article {33, title = {Distinct architecture of lymphatic vessels induced by chimeric vascular endothelial growth factor-C/vascular endothelial growth factor heparin-binding domain fusion proteins}, journal = {Circ Res}, volume = {100}, year = {2007}, month = {2007/May/}, pages = {1468 - 75}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/17478733}, author = {Tammela, Tuomas and He, Yulong and Lyytikk{\"a}, Johannes and Jeltsch, Michael and Markkanen, Johanna and Pajusola, Katri and Yl{\"a}-Herttuala, Seppo and Alitalo, Kari} } @article {34, title = {Enhanced capillary formation stimulated by a chimeric vascular endothelial growth factor/vascular endothelial growth factor-C silk domain fusion protein}, journal = {Circ Res}, volume = {100}, year = {2007}, month = {2007/May/}, pages = {1460 - 7}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/17478734}, author = {Keskitalo, Salla and Tammela, Tuomas and Lyytikka, Johannes and Karpanen, Terhi and Jeltsch, Michael and Markkanen, Johanna and Yla-Herttuala, Seppo and Alitalo, Kari} } @article {32, title = {Vascular endothelial growth factor (VEGF)/VEGF-C mosaic molecules reveal specificity determinants and feature novel receptor binding patterns}, journal = {J Biol Chem}, volume = {281}, year = {2006}, month = {2006/Apr/}, pages = {12187 - 95}, abstract = {Vascular endothelial growth factors (VEGFs) and their receptors play key roles in angiogenesis and lymphangiogenesis. VEGF activates VEGF receptor-1 (VEGFR-1) and VEGFR-2, whereas VEGF-C activates VEGFR-2 and VEGFR-3. We have created a library of VEGF/VEGF-C mosaic molecules that contains factors with novel receptor binding profiles, notably proteins binding to all three VEGF receptors ("super-VEGFs"). The analyzed super-VEGFs show both angiogenic and lymphangiogenic effects in vivo, although weaker than the parental molecules. The composition of the VEGFR-3 binding molecules and scanning mutagenesis revealed determinants of receptor binding and specificity. VEGFR-2 and VEGFR-3 showed striking differences in their requirements for VEGF-C binding; extracellular domain 2 of VEGFR-2 was sufficient, whereas in VEGFR-3, both domains 1 and 2 were necessary.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/16505489}, author = {Jeltsch, Michael and Karpanen, Terhi and Strandin, Tomas and Aho, Kukka and Lankinen, Hilkka and Alitalo, Kari} } @article {29, title = {Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation}, journal = {J Clin Invest}, volume = {115}, year = {2005}, month = {2005/Feb/}, pages = {247 - 57}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/15668734}, author = {Baluk, Peter and Tammela, Tuomas and Ator, Erin and Lyubynska, Natalya and Achen, Marc G and Hicklin, Daniel J and Jeltsch, Michael and Petrova, Tatiana V and Pytowski, Bronislaw and Stacker, Steven A and Yl{\"a}-Herttuala, Seppo and Jackson, David G and Alitalo, Kari and McDonald, Donald M} } @article {27, title = {Intrinsic versus microenvironmental regulation of lymphatic endothelial cell phenotype and function}, journal = {FASEB J}, volume = {17}, year = {2003}, month = {2003/Nov/}, pages = {2006 - 13}, abstract = {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.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/14597670}, author = {Veikkola, Tanja and Lohela, Marja and Ikenberg, Kristian and M{\"a}kinen, Taija and Korff, Thomas and Saaristo, Anne and Petrova, Tatania and Jeltsch, Michael and Augustin, Hellmut G and Alitalo, Kari} } @article {26, title = {VEGF guides angiogenic sprouting utilizing endothelial tip cell filopodia}, journal = {J Cell Biol}, volume = {161}, year = {2003}, month = {2003/Jun/}, pages = {1163 - 77}, abstract = {Vascular endothelial growth factor (VEGF-A) is a major regulator of blood vessel formation and function. It controls several processes in endothelial cells, such as proliferation, survival, and migration, but it is not known how these are coordinately regulated to result in more complex morphogenetic events, such as tubular sprouting, fusion, and network formation. We show here that VEGF-A controls angiogenic sprouting in the early postnatal retina by guiding filopodial extension from specialized endothelial cells situated at the tips of the vascular sprouts. The tip cells respond to VEGF-A only by guided migration; the proliferative response to VEGF-A occurs in the sprout stalks. These two cellular responses are both mediated by agonistic activity of VEGF-A on VEGF receptor 2. Whereas tip cell migration depends on a gradient of VEGF-A, proliferation is regulated by its concentration. Thus, vessel patterning during retinal angiogenesis depends on the balance between two different qualities of the extracellular VEGF-A distribution, which regulate distinct cellular responses in defined populations of endothelial cells.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/12810700}, author = {Gerhardt, Holger and Golding, Matthew and Fruttiger, Marcus and Ruhrberg, Christiana and Lundkvist, Andrea and Abramsson, Alexandra and Jeltsch, Michael and Mitchell, Christopher and Alitalo, Kari and Shima, David and Betsholtz, Christer} } @article {20, title = {Intravascular adenovirus-mediated VEGF-C gene transfer reduces neointima formation in balloon-denuded rabbit aorta}, journal = {Circulation}, volume = {102}, year = {2000}, month = {2000/Oct/}, pages = {2262 - 8}, abstract = {BACKGROUND: Gene transfer to the vessel wall may provide new possibilities for the treatment of vascular disorders, such as postangioplasty restenosis. In this study, we analyzed the effects of adenovirus-mediated vascular endothelial growth factor (VEGF)-C gene transfer on neointima formation after endothelial denudation in rabbits. For comparison, a second group was treated with VEGF-A adenovirus and a third group with lacZ adenovirus. Clinical-grade adenoviruses were used for the study. METHODS AND RESULTS: Aortas of cholesterol-fed New Zealand White rabbits were balloon-denuded, and gene transfer was performed 3 days later. Animals were euthanized 2 and 4 weeks after the gene transfer, and intima/media ratio (I/M), histology, and cell proliferation were analyzed. Two weeks after the gene transfer, I/M in the lacZ-transfected control group was 0. 57+/-0.04. VEGF-C gene transfer reduced I/M to 0.38+/-0.02 (P:<0.05 versus lacZ group). I/M in VEGF-A-treated animals was 0.49+/-0.17 (P:=NS). The tendency that both VEGF groups had smaller I/M persisted at the 4-week time point, when the lacZ group had an I/M of 0.73+/-0.16, the VEGF-C group 0.44+/-0.14, and the VEGF-A group 0. 63+/-0.21 (P:=NS). Expression of VEGF receptors 1, 2, and 3 was detected in the vessel wall by immunocytochemistry and in situ hybridization. As an additional control, the effect of adenovirus on cell proliferation was analyzed by performing gene transfer to intact aorta without endothelial denudation. No differences were seen in smooth muscle cell proliferation or I/M between lacZ adenovirus and 0.9\% saline-treated animals. CONCLUSIONS: Adenovirus-mediated VEGF-C gene transfer may be useful for the treatment of postangioplasty restenosis and vessel wall thickening after vascular manipulations.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/11056103}, author = {Hiltunen, M O and Laitinen, M and Turunen, M P and Jeltsch, M and Hartikainen, J and Rissanen, T T and Laukkanen, J and Niemi, M and Kossila, M and H{\"a}kkinen, T P and Kivel{\"a}, A and Enholm, B and Mansukoski, H and Turunen, A M and Alitalo, K and Yl{\"a}-Herttuala, S} } @article {10, title = {Hyperplasia of lymphatic vessels in VEGF-C transgenic mice}, journal = {Science (80- )}, volume = {276}, year = {1997}, month = {1997/May/}, pages = {1423 - 5}, abstract = {No growth factors specific for the lymphatic vascular system have yet been described. Vascular endothelial growth factor (VEGF) regulates vascular permeability and angiogenesis, but does not promote lymphangiogenesis. Overexpression of VEGF-C, a ligand of the VEGF receptors VEGFR-3 and VEGFR-2, in the skin of transgenic mice resulted in lymphatic, but not vascular, endothelial proliferation and vessel enlargement. Thus, VEGF-C induces selective hyperplasia of the lymphatic vasculature, which is involved in the draining of interstitial fluid and in immune function, inflammation, and tumor metastasis. VEGF-C may play a role in disorders involving the lymphatic system and may be of potential use in therapeutic lymphangiogenesis.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/9162011}, author = {Jeltsch, M and Kaipainen, A and Joukov, V and Meng, X and Lakso, M and Rauvala, H and Swartz, M and Fukumura, D and Jain, R K and Alitalo, K} } @article {9, title = {VEGF-C receptor binding and pattern of expression with VEGFR-3 suggests a role in lymphatic vascular development}, journal = {Development}, volume = {122}, year = {1996}, month = {1996/Dec/}, pages = {3829 - 37}, abstract = {The vascular endothelial growth factor family has recently been expanded by the isolation of two new VEGF-related factors, VEGF-B and VEGF-C. The physiological functions of these factors are largely unknown. Here we report the cloning and characterization of mouse VEGF-C, which is produced as a disulfide-linked dimer of 415 amino acid residue polypeptides, sharing an 85\% identity with the human VEGF-C amino acid sequence. The recombinant mouse VEGF-C protein was secreted from transfected cells as VEGFR-3 (Flt4) binding polypeptides of 30-32x10(3) Mr and 22-23x10(3) Mr which preferentially stimulated the autophosphorylation of VEGFR-3 in comparison with VEGFR-2 (KDR). In in situ hybridization, mouse VEGF-C mRNA expression was detected in mesenchymal cells of postimplantation mouse embryos, particularly in the regions where the lymphatic vessels undergo sprouting from embryonic veins, such as the perimetanephric, axillary and jugular regions. In addition, the developing mesenterium, which is rich in lymphatic vessels, showed strong VEGF-C expression. VEGF-C was also highly expressed in adult mouse lung, heart and kidney, where VEGFR-3 was also prominent. The pattern of expression of VEGF-C in relation to its major receptor VEGFR-3 during the sprouting of the lymphatic endothelium in embryos suggests a paracrine mode of action and that one of the functions of VEGF-C may be in the regulation of angiogenesis of the lymphatic vasculature.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/9012504}, author = {Kukk, E and Lymboussaki, A and Taira, S and Kaipainen, A and Jeltsch, M and Joukov, V and Alitalo, K} }