Vesicular Stomatitis Virus Glycoprotein– and Venezuelan Equine Encephalitis Virus-Derived Glycoprotein–Pseudotyped Lentivirus Vectors Differentially Transduce Corneal Endothelium, Trabecular Meshwork, and Human Photoreceptors

Abstract

The ability to deliver a large transgene efficiently to photoreceptors using viral vectors remains problematic and yet is critical for the future therapy of inherited retinal diseases such as Stargardt's and Usher's 1B. Herein, we examine the ocular tropism of a HIV-1-based lentivirus vector pseudotyped with Venezuelan equine encephalitis virus-derived glycoprotein (VEEV-G) after intraocular delivery to the posterior and anterior chambers of C57BL/6 wild-type mice. Reporter gene (EGFP) expression was evaluated using in vivo fluorescence imaging followed by postmortem immunohistochemistry and retinal function assessed by electroretinography. Intracameral administration of VEEV-G and vesicular stomatitis virus glycoprotein (VSV-G)-pseudotyped vectors resulted in robust transgene expression in the corneal endothelium and trabecular meshwork. After subretinal administration, onset of transgene expression was observed in the retinal pigment epithelium (RPE) 1 day postinjection with both VEEV-G and control VSV-G pseudotypes, but no significant photoreceptor transduction was apparent. Substantial degeneration of the outer nuclear layer was observed with VEEV-G-pseudotyped vector, which corresponded to ablation of retinal function. Subretinal administration of VSV-G was observed to result in significant suppression of electrophysiological function compared with buffer-injected and uninjected control eyes. Suppression of the c-wave amplitude, in addition to reduced RPE65 expression, indicated potential RPE dysfunction. Ex vivo tropism of VSV-G was assessed using organotypic culture of explanted retina harvested from wild-type mice and human patients undergoing retinal detachment surgery to examine the prevention of transduction by physical barriers and species differences in tropism.

Vector platforms for gene therapy of inherited retinopathies

“…However, HIV-1-Mokola and Ross River Virus (HIV-1-RRV) were shown to transduce only RPE after subretinal delivery (Auricchio et al, 2001; Bemelmans et al, 2005; Greenberg et al, 2007). Recently, HIV-1-based vectors pseudotyped with the Venezuelan Equine Encephalitis Virus-derived glycoprotein (VEEVG) were shown to transduce murine RPE after subretinal delivery (Lipinski et al, 2014), although degeneration of the ONL was observed with this pseudotype. A LV vector based on the HIV-2 genome was reported to transduce PR after subretinal injection in adult rabbits (Cheng et al, 2002).…”

“…Although LV-VSVG vector binding seemed independent of specific cell surface receptors (Coil and Miller, 2004), studies carried out in adult murine retinal explants, which lack physical barriers since they are compromised during the process of explantation, have shown that LV-VSVG cannot transduce PR (Lipinski et al, 2014). Surprisingly, limited PR transduction was observed in a human retinal explant transduced with LV-VSVG, suggesting that transduction may be species-dependent (Lipinski et al, 2014). …”

Promising and delivering gene therapies for vision loss

“…The later development of a modified replication-deficient HIV-derived retroviral vector allowed the transduction of non-dividing cells 99 and was subsequently shown to successfully target photoreceptors and RPE cells, cornal endothelium and trabecular meshwork 43,100,101 . However the percentage of transduced mouse photoreceptors after lentiviral gene delivery still remains higher in newborn retinas compared to adult mice 102 .…”

La conception de vecteurs adaptés à la thérapie génique oculaire

“…De nombreuses études montrent que, lorsqu'ils sont injectés par voie sous-rétinienne, les lentivirus transduisent efficacement l'épithélium rétinien pigmentaire chez les rongeurs [15,16], mais la transduction des photorécepteurs reste variable [17,18]. L'efficacité de transduction des photorécepteurs par les lentivirus dépend de l'origine du lentivirus et de l'espèce étudiée [19]. Par exemple, les lentivirus d'origine équine donnent de bons résultats de transduction des photorécepteurs situés à proximité du site d'injection chez le primate non humain [19,20].…”

“…L'efficacité de transduction des photorécepteurs par les lentivirus dépend de l'origine du lentivirus et de l'espèce étudiée [19]. Par exemple, les lentivirus d'origine équine donnent de bons résultats de transduction des photorécepteurs situés à proximité du site d'injection chez le primate non humain [19,20]. Deux essais cliniques sont en cours pour traiter la 3 épisomale (pour le virus recombinant).…”