Inhibition of Choroidal Neovascularization via Brief Subretinal Exposure to a Newly Developed Lentiviral Vector Pseudotyped with Sendai Viral Envelope Proteins

Lentiviral vectors are promising tools for the treatment of chronic retinal diseases, including age-related macular degeneration (AMD), as they enable stable transgene expression. On the other hand, Sendai virus (SeV) vectors provide the unique advantage of rapid gene transfer. Here we show that novel simian immunodeficiency viral vectors pseudotyped with SeV envelope proteins (SeV-F/HN-SIV) achieved rapid, efficient, and long-lasting gene transfer in the mouse retina. Subretinal exposure to SeV-F/HN-SIV vectors for only a few minutes resulted in high-level gene transfer to the retinal pigment epithelium, whereas several hours were required for gene transfer by standard vesicular stomatitis virus G-pseudotyped SIV vectors. Transgene expression continued over a 1-year period. SeV-F/HN-SIV vector-mediated retinal overexpression of soluble Fms-like tyrosine kinase-1 (sFlt-1) or pigment epithelium-derived factor (PEDF) significantly suppressed laser-induced choroidal neovascularization (CNV). Histologically, 6-month-long sustained overexpression of PEDF did not adversely affect the retina; however, that with sFlt-1 resulted in photoreceptor degeneration associated with choroidal circulation defects. These data demonstrate that brief subretinal administration of SeV-F/HN-SIV vectors may facilitate safe and efficient retinal gene transfer, and suggest the therapeutic potential of PEDF with a higher safety profile for treating CNV in AMD patients.