Vammin induces a highly efficient angiogenic response through VEGFR-2/NRP-1 and bypasses the regulatory function of VEGFR-1

Rationale: VEGF family members mediate their effects through cell surface receptors VEGFR-1, VEGFR-2 and NRP. Specific ligands were used to stimulate specific combinations of the receptors to evaluate ligand and receptor properties. Objective: The properties of a novel VEGF family member Vammin were studied in level of receptor binding, gene expression in HUVECs by RNAseq and in vivo using adenoviral gene trasfers. Methods: HUVECs were trasduced using adenoviral vectors encoding VEGF-A109, VEGF-A165 and Vammin and with an empty vector as a control. Gene expression was measured using RNA sequencing. Adenoviral intramuscular gene transfers were performed into rabbit hindlimbs. Confocal and multiphoton microscopy were used for blood vessel imaging. Results and conclusions: Vammin is a highly effective VEGFR2 ligand that induces differential gene expression of genes related to proliferation, survival, angiogenesis and blood vessel development in HUVECs. The effect is stronger than ones induced by VEGF-A165 and VEGF-A109. Vammin induces highly efficient angiogenic responses when delivered into rabbit skeletal muscles using adenoviral gene transfers. Overall design: HUVEC mRNA profiles after adenoviral vector gene transfers in duplicate.

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Toivanen PI, Nieminen T, Laakkonen JP, Heikura T, Kaikkonen MU, Ylä-Herttuala S