Induction of RPE-specific markers in human sweat gland-derived stem cells by xenogeneic co-culture with porcine RPE cells

Purpose: There is an increasing interest in generating retinal pigment epithelial (RPE) cells from stem cells for treatment of macular degeneration. Human sweat glands are a rich source of nestin-positive stem cells. In this study, the possibility of inducing RPE-specific markers in human sweat gland-derived stem cells (SGSCs) by xenogeneic co-culture with porcine RPE cells was investigated. Methods: SGSCs were isolated out of adult human scalp skin, purified and seeded on laminin-coated cover slips. Then they were co-cultured with porcine RPE cells seeded on laminin-coated transwell inserts or mono-cultured without RPE cells for 5 days. Afterwards they were washed, fixed, stained (Bestrophin, MITF, PMEL, MERTK, CRALBP and RPE65) and analyzed by fluorescence microscopy. Results: SGSCs expressed Bestrophin and MITF on laminin-coated cover slips even when mono-cultured without RPE cells whereas PMEL, MERTK, CRALBP and RPE65 were only detectable after co-culture with RPE cells. Conclusions: Adult human sweat gland-derived stem cells can be directed into expressing RPE-specific proteins even by xenogeneic co-culture with porcine RPE cells. The presented system is an effective tool to predict the behavior of SGSCs after transplantation into the subretinal environment by mimicking the situation in vivo.