gms | German Medical Science

Purpose: The treatment of retinal degenerations using subretinal pigment epithelial cell transplantation has resulted in very limited success. One reason may be that the transplanted cells did not secrete necessary factors to maintain a healthy environment. Here, we detail a protocol for the efficient and stable transfection of primary pigment epithelial cells with pigment epithelium-derived factor (PEDF) using the hyperactive Sleeping Beauty (SB100X) transposon system. Transplantation of these cells would engender an anti-angiogenic and neuroprotective subretinal microenvironment.

Methods: Using electroporation, ARPE-19 and primary pigment epithelial cells were transfected with a control or a PEDF encoding plasmid, controlled either by a CMV or a CAG promoter. Transfection efficiency and protein expression stability were evaluated by flow cytometry and Western blot analysis.

Results: SB100X-based gene delivery resulted in efficiencies of 100% with the control and 40% with the PEDF encoding plasmid. Subsequent sorting enabled establishment of populations containing 99% PEDF-transfected cells. PEDF secretion was maintained in all cell types for the 8 months the cells have been followed. However, PEDF secretion was higher under the control of the CMV than the CAG promoter.

Conclusions: We have shown that SB100X-mediated gene transfer ensured the stable expression and continuous secretion of PEDF in primary pigment epithelial cells. Transfection with the SB100X system results in the transgene integration into the host cell’s genome without potential complications of retroviral mediated gene delivery and is therefore an important step in the development of a cell-based, non-viral gene addition therapy for retinal degenerative diseases.