@article {588, title = {Factors regulating the substrate specificity of cytosolic phospholipase A2-alpha in vitro}, journal = {Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids}, volume = {1861}, year = {2016}, month = {2016/07/01/}, pages = {1597}, keywords = {Arachidonic acid, Bilayer, Catalytic site, Mass spectrometry, Micelle, Phospholipase A}, author = {Batchu, Krishna Chaithanya and H{\"a}nninen, Satu and Jha, Sawan Kumar and Jeltsch, Michael and Somerharju, Pentti} } @article {527, title = {Lymphatic Vessels in Regenerative Medicine and Tissue Engineering}, journal = {Tissue Engineering Part B}, volume = {22}, year = {2016}, month = {2016}, pages = {1-13}, type = {Review}, abstract = {Once a DOI is available for this article, the final publication will be available from Mary Ann Liebert, Inc., publishers at http://dx.doi.org/10.1089/TEN.TEB.2016.0034. The postprint manuscript is available from here and for the next 30 days also from the publisher via this bit.ly shortcut: http://bit.ly/1VKjjMk. }, doi = {10.1089/ten.TEB.2016.0034}, url = {http://online.liebertpub.com/doi/10.1089/ten.TEB.2016.0034}, author = {Schaupper, Mira V. and Jeltsch, Michael and Rohringer, Sabrina and Redl, Heinz and Holnthoner, Wolfgang} } @article {481, title = {Substrate efflux propensity is the key determinant of iPLA-β-mediated glycerophospholipid hydrolysised}, journal = {Journal of Biological Chemistry}, year = {2015}, month = {2015/02/23}, abstract = {A-type phospholipases (PLAs) are key players in glycerophospholipid (GPL)homeostasis and in mammalian cells, Ca2+-independent PLA-beta (iPLAβ) in particular has been implicated in this essential process.However, the regulation of this enzyme,which is necessary to avoid futile competition between synthesis and degradation, is not understood. Recently, we provided evidence that the efflux of the substrate molecules from the bilayer is the rate-limiting step in the hydrolysis of GPLs by some secretory nonhomeostatic) PLAs. To study if this is the case with iPLAβ as well a mass-spectrometric assay was employed to determine the rate of hydrolysis of multiple saturated and unsaturated GPL species in parallel using micelles or vesicle bilayers as the macrosubstrate. With micelles, the hydrolysis decreased with increasing acyl chain length independent of unsaturation and modest discrimination between acyl positional isomers was observed, presumably due to the differences in the structure of the sn1 and sn2 acyl binding sites of the protein. In striking contrast, no significant discrimination between positional isomers was observed with bilayers, and the rate of hydrolysis decreased with the acyl chain length logarithmically and far more than with micelles. These data provide compelling evidence that efflux of the substrate molecule from the bilayer, which also decreases monotonously with acyl chain length, is the rate-determining step in iPLAβ- mediated hydrolysis of GPLs in membranes. This finding is intriguing as it may help to understand how homeostatic PLAs are regulated and how degradation and biosynthesis are coordinated.}, doi = {10.1074/jbc.M115.642835}, url = {http://www.jbc.org/content/early/2015/02/23/jbc.M115.642835.abstract}, author = {Batchu, Krishna Chaithanya and Hokynar, Kati and Jeltsch, Michael and Mattonet, Kenny and Somerharju, Pentti} } @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 {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 {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 {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 {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 {35, title = {The tyrosine kinase inhibitor cediranib blocks ligand-induced vascular endothelial growth factor receptor-3 activity and lymphangiogenesis}, journal = {Cancer Res}, volume = {68}, year = {2008}, month = {2008/Jun/}, pages = {4754 - 62}, abstract = {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