Lentivirus-mediated sFlt-1 gene fragment transfer suppresses retinal neovascularization.
OBJECTIVE
sFlt-1, a soluble secreted variant of the vascular endothelial growth factor (VEGF) receptor-1 that possesses only its extracellular domain, is a specific endogenous inhibitor of VEGF, which is involved in retinal vasculogenesis. Our objective was to determine the effects of various sFlt-1 gene fragments on retinal neovascularization in vivo using a murine oxygen-induced ischemic retinopathy (OIR) model.


METHODS
Lentiviral expression plasmids carrying the sFlt-1 gene fragments containing Ig-like domains 2nd-3rd and 2nd-4th were constructed. Retinal neovascularization was induced by exposing neonatal mice to hyperoxia (75% O(2)) on post-natal day 7 (P7) and then returning them to normoxia (21% O(2)) on P12. After sFlt-1 gene fragment transfer, retinal neovascularization was examined via fluorescein angiography and hematoxylin-eosin staining. In addition, changes in the expression of VEGF and its functional receptor KDR/Flk-1 were examined via Western blotting and immunohistochemistry.


RESULTS
Lenti.sFlt-1(2-3) and lenti.sFlt-1(2-4) both significantly inhibited neovascularization in OIR mice. Retinas from mice treated with lenti.sFlt-1(2-3) demonstrated a more marked reduction in neovascular cell nuclei compared with mice treated with lenti.sFlt-1(2-4), and these results were confirmed by fluorescence angiography. Gene transfer showed a very weak effect on VEGF protein expression, whereas KDR/Flk-1 protein expression was strongly inhibited, particularly in mice treated with lenti.sFlt-1(2-3).


CONCLUSIONS
Lentivirus-mediated sFlt-1 gene transfer significantly inhibits retinal neovascularization in OIR. Thus, sFlt-1 gene transfer may represent a potential therapeutic strategy for preventing retinal neovascularization.
Min
Zhang
Z
Department of Ophthalmology, Shanghai No. 6 People's Hospital, Shanghai, PR China.
Qiang
Wu
W
Benwen
Song
S
Bin
Lu
L
Xinhua
Du
D
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D005451:Fluorescein Angiography; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D007150:Immunohistochemistry; D007511:Ischemia / Q000139:chemically induced / Q000150:complications; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D010100:Oxygen; D010446:Peptide Fragments / Q000235:genetics*; D015861:Retinal Neovascularization / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism / Q000628:therapy*; D012171:Retinal Vessels; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors / Q000235:genetics*
D010446:Peptide Fragments; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2; D010100:Oxygen