Purchase this article with an account.
Sandra Johnen, Sabine Diarra, Nina Harmening, Corinne Marie, Daniel Scherman, Zsuzsanna Izsvák, Peter Walter, Gabriele Thumann; Genetic engineering of freshly isolated primary human pigment epithelial cells by non-viral gene delivery for the treatment of neovascular AMD. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4489.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Gene therapy is a promising treatment for many diseases, and viral vectors are already used in clinical applications. However, their drawbacks have encouraged the improvement of non-viral strategies. We have developed an approach for the treatment of neovascular age-related macular degeneration (nAMD). nAMD is characterized by choroidal blood vessels growing into the subretinal space, which results from an overexpression of the vascular endothelial growth factor and a decreased expression of the pigment epithelium-derived factor (PEDF). Our therapeutic approach involves the transplantation of pigment epithelial (PE) cells that have been engineered to stably overexpress PEDF. The PEDF transgene is incorporated into the cell’s genome by the Sleeping Beauty (SB100X) transposon system delivered by electroporation of non-viral miniplasmids free of antibiotic resistance markers (pFAR).
Immediately after isolation, PE cells from human donor eyes were co-transfected with two pFAR4 derivatives encoding PEDF and the SB100X transposase using two different electroporation systems. PEDF secretion was evaluated by immunoblotting and quantified by ELISA. PEDF gene expression was analyzed via quantitative real-time PCR (qRT-PCR).
Effective transfection was demonstrated in various independently performed experiments using as few as 2x104 freshly isolated cells. The amount of secreted PEDF was 0.6 ng/h/1x104 cells, and thus 6-fold higher compared to the PEDF secretion rate of non-transfected cells. qRT-PCR analysis revealed a 3.2-fold increase in the median of total PEDF gene expression compared to the endogenous level. However, extended postmortem times until cell isolation resulted in reduced PEDF ratios.
SB100X-mediated transfection of freshly isolated PE cells resulted in an increase in both PEDF secretion and PEDF gene expression. The pFAR technology further improves the biosafety of non-viral gene transfer, as it allows for plasmid propagation in the absence of antibiotics, which is a crucial safety issue for human trials. The transfection of freshly isolated PE cells is an important step towards the ultimate goal of the TargetAMD project, which is the efficient and safe delivery of the PEDF transgene to autologous cells ex vivo, followed by the transplantation to the subretinal space of nAMD patients.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only