title: Enhanced anti-angiogenic effect of a deletion mutant of plasminogen kringle 5 on neovascularization.
abstract: Kringle 5 (K5), a proteolytic fragment of plasminogen, has been proved to be an angiogenic inhibitor. Previously, we have evaluated the effect of K5 on the vascular leakage and neovascularization in a rat model of oxygen-induced retinopathy. In this study, we expressed K5 and a deletion mutant of K5 (K5 mutant) in a prokaryocyte expression system and purified them by affinity chromatography. K5 mutant was generated by deleting 11 amino acids from K5 while retaining the three disulfide bonds. The anti-angiogenic activity of intact K5 and K5 mutant were compared in endothelial cells and retinal neovascularization rat model. K5 mutant inhibited the proliferation of primary human retinal capillary endothelial cells (HRCEC) in a concentration-dependent manner, with an apparent EC50 of approximate 35 nmol/L, which is twofold more potent than intact K5. In the even higher concentration range, K5 mutant did not inhibit pericytes from the same origin of HRCEC, which suggested an endothelial cell-specific inhibition. K5 mutant had no effect on normal liver cells and Bel7402 hepatoma cells even at high concentration range either. Intravitreal injection of the K5 and mutant in the oxygen-induced retinopathy rat model both resulted in significantly fewer neovascular tufts and nonperfusion area than controls with PBS injection, as shown by fluorescein angiography. Furthermore, K5 mutant exhibited more strong inhibition effect on neovascularization than intact K5 by quantification of vascular cells. These results suggest that this K5 deletion mutant is a more potent angiogenic inhibitor than intact K5 and may have therapeutic potential in the treatment of those disorders with neovascularization, such as solid tumor, diabetic retinopathy, age-related macular degeneration, rheumatoid arthritis, and hyperplasia of prostate.
authors.affiliation: Department of Biochemistry, Zhongshan Medical School, Sun Yat-sen University, Guangzhou 510089, Guangdong Province, China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Cai
authors.forename: Jianfang
authors.initials: J
authors.lastname: Ma
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Li
authors.forename: Zhonghan
authors.initials: Z
authors.lastname: Yang
authors.forename: Xia
authors.initials: X
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Zuguo
authors.initials: Z
authors.lastname: Liu
authors.forename: Mintao
authors.initials: M
authors.lastname: Li
authors.forename: Guoquan
authors.initials: G
authors.lastname: Gao
mesh_terms: D020533:Angiogenesis Inhibitors / Q000378:metabolism*; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003930:Diabetic Retinopathy / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D017353:Gene Deletion; D006801:Humans; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D010958:Plasminogen / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D020533:Angiogenesis Inhibitors; D010446:Peptide Fragments; D011994:Recombinant Proteins; C491499:plasminogen kringle 5; D010958:Plasminogen