Adeno-associated virus type-2 expression of pigmented epithelium-derived factor or Kringles 1–3 of angiostatin reduce retinal neovascularization

Abstract

Neovascular diseases of the retina include age-related macular degeneration and diabetic retinopathy, and together they comprise the leading causes of adult-onset blindness in developed countries. Current surgical, pharmaceutical, and laser therapies for age-related macular degeneration (AMD) rarely result in improved vision, do not significantly prevent neovascularization (NV), and often result in at least some vision loss. To address this therapeutic gap, we determined the efficacy of recombinant adeno-associated viral (rAAV) serotype-2-mediated expression of pigment epithelium-derived factor (PEDF) or Kringle domains 1-3 of angiostatin (K1K3) in reducing aberrant vessel formation in a mouse model of ischemia-induced retinal NV. Both PEDF and K1K3 are potent inhibitors of NV when injected directly, hence expression of these therapeutic factors from rAAV may provide long-term protection from neovascular eye disease. rAAV vectors expressing the therapeutic gene were injected into one eye of postnatal day 0 (P0) newborn mouse pups. Retinal NV was induced in P7 mice by exposure to elevated oxygen for 5 days followed by room air for another five days. Retinal NV was quantified by the number of vascular-endothelial-cell nuclei above the inner-limiting membrane in P17 eyes. The number of such vascular endothelial cell nuclei in eyes treated with rAAV-PEDF or rAAV-K1K3 was significantly reduced (both P < 0.0000002) compared with control eyes. Ocular protein levels detected by ELISA correlate well with the reduction in NV and confirm that expression of antineovascular agents from rAAV vectors may be a therapeutically useful treatment of retinal or choroidal neovascular disease.

Recombinant AAV-mediated gene transfer to the retina: gene therapy perspectives

“…The number of such vascular endothelial cell nuclei in eyes treated with rAAV-2/2pedf and rAAV-2/2k1k3 was significantly reduced compared with untreated eyes. 61 For rAAV-2/ Recombinant AAV-mediated gene transfer to the retina F Rolling 2sFlt1 assessment, the vector was intravitreally injected at P2 and retinal neovascularization was quantified on retinal flatmounts following perfusion with dextranconjugated FITC at p19. Eyes injected with AAV-2/2sFlt1 displayed fewer neovascular complexes than PBS-injected eyes.…”

Gene transfer for ocular neovascularization and macular edema

“…Intraocular adeno-associated virus (AAV) 2-mediated gene transfer of Pedf also suppressed the retinal and choroidal NV. [43][44][45] Injection of AdPEDF.11 beneath the conjunctiva along the outer border of the sclera resulted in transduction of episcleral cells that produced PEDF on the outside of the eye. 46,47 The PEDF penetrated the sclera, resulting in high levels in the choroid that caused regression of choroidal NV.…”

“…Similarly, intraocular injection of angiostatin packaged in AAV or lentiviral vectors suppressed retinal and choroidal NV. 45,69,70 Oxford BioMedica UK Ltd (Oxford, UK) has taken advantage of the large capacity of lentiviral vectors to package both endostatin and angiostatin in equine infectious anemia viral vectors. Expression of endostatin and angiostatin suppresses leakage and growth of choroidal NV in mice.…”

Seeing the light: New insights into the molecular pathogenesis of retinal diseases

“…Expression of pigment epithelium-derived factor (PEDF) has been shown to suppress ocular neovascularization in several models (Mori et al, 2001a(Mori et al, ,b, 2002Auricchio et al, 2002;Raisler et al, 2002;Gehlbach et al, 2003a) and a phase I trial in patients with neovascular AMD showed promise . Other promising transgenes for treatment of ocular neovascularization include endostatin, which reduces excessive vascular permeability in addition to suppressing neovascularization (Auricchio et al, 2002;Takahashi et al, 2003), angiostatin (Lai et al, 2001a;Raisler et al, 2002;Igarashi et al, 2003), and soluble VEGF receptor 1 (Honda et al, 2000;Lai et al, 2001bLai et al, , 2005Bainbridge et al, 2002;Gehlbach et al, 2003b;Rota et al, 2004).…”