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"anti-angiogenic effect of galectin inhibitors in in vivo and in vitro models"

Grant number: 12/20975-3
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): March 01, 2013
Effective date (End): August 31, 2014
Field of knowledge:Biological Sciences - Biochemistry
Principal Investigator:Juliana Luporini Dreyfuss Regatieri
Grantee:Danielle Stoll
Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

The study of new molecules with anti-angiogenic activity is crucial to treat diseases that involve the formation of new vessels as choroidal neovascularization secondary to age-related macular degeneration and cancer. The galectins are a family of proteins from the lectins family that specifically recognize the beta-galactosides. The galectins are involved in a variety of biological processes including differentiation, adhesion, proliferation and apoptosis. It is known that angiogenesis is regulated by growth factors such as VEGF-A, EGF and TGF-± and their receptors. The cell surface receptors of these growth factors are glycosylated and directly interact with galectin-3 mediating angiogenesis in vitro. This protein also promotes reepithelialization by activating the complex of extracellular matrix molecules and integrins, and angiogenesis mediated by binding to glycosylated portion of integrin ±v²3 and subsequent activation of signaling pathways that promote the growth of new blood vessels. The objective of this study is to investigate whether the binding of galectin-3, a beta-galactoside lactose analogue -D-thiogalactopyranosyde (TDG), which is known to block the binding of carbohydrate-dependent galectins to their ligands, is able to inhibit angiogenesis in vitro and in vivo. We will perform experiments involving viability, proliferation, adhesion, migration and formation of capillary like structures in Matrigel in endothelial cells before and after treatment of these cultures with 0.01 mg/mL, 0.1 mg/mL and 1 mg/mL of TDG. After in vitro assays, in vivo experiments will be performed including inhibition of choroidal neovascularization induced by laser in mice C57BL10. The induction of choroidal neovascularization will be performed by argon laser photocoagulation. Afterwards, intravitreal injection of different concentrations of TDG. The area of neovascularization will be evaluated by immunofluorescence after two weeks in flatmount choroidal using anti-Von Willebrand factor, specific marker of endothelial cells.