Abstract
Purpose :
ANGPTL3, a member of the angiopoietin-like family, is a liver-specific secreted factor and a determinant factor of HDL level (Jin et al. 2007). It was also suggested that ANGPTL3 plays a role in the regulation of angiogenesis (Camenisch et al. 2002). To investigate whether ANGPTL3 possesses angiogenic potential, we injected plasmid encoding ANGPTL3 into mouse corneal stroma and compared with corneal neovascularization (CoNV) induced by injection of plasmid encoding mouse vascular endothelial growth factor (mVEGF164).
Methods :
Study 1. Dose response: C57Bl/6J mice received corneal intrastromal injections of different amounts (1.5, 3 and 6 μg in 2 μL) of pRG977.ANGPTL3-eGFP plasmid or pRG977.mVEGF164-eGFP plasmid for observation of CoNV. Study 2. Inhibition by VEGF-Trap of CoNV: VEGF Trap (12.5 mg/kg) was administrated intraperitoneally on Day 0, and Day 7 post corneal intrastromal injections of pRG977.mVEGF164-eGFP plasmid (6 μg in 2 μL). Human IgG Fc (6.25 mg/kg) was used as control. On Day 14, DyLight 594 tomato lectin iv injection was applied to both studies for vascular staining, and tissues were harvested for flat mount followed by fluorescence microscopy for imaging of eGFP and corneal vessels. hANGPTL3 and mVEGF protein levels in corneas were measured by ELISA.
Results :
The CoNV induced by intrastromal injection of pRG977.mVEGF164-eGFP was dose-dependent and was proportional to the extent of eGFP expression, as expected. Systemically administered VEGF Trap provided complete inhibition of the CoNV. Corneas injected with pRG977.ANGPTL3-eGFP plasmid did not develop CoNV at any dose, although eGFP expression was observed and proportional to the amount of plasmid received. The protein expression levels of hANGPTL3 and mVEGF in the corneas receiving either plasmid were obtained by ELISA.
Conclusions :
Corneal intrstromal injection of plasmid DNA encoding VEGF produces a reliable and reproducible CoNV in mice, which is suitable for evaluating the effects of angiogenic and anti-angiogenic agents. ANGPTL3 does not possess angiogenic potential in this model.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.