Human Bone Marrow Stromal Cells can Differentiate to a Retinal Pigment Epithelial Phenotype when Co-Cultured with Pig Retinal Pigment Epithelium using a Transwell System

Abstract

Background: There is an increasing interest in generating retinal pigment epithelial (RPE) cells from stem cells for therapy against degenerative eye diseases. Human bone marrow stromal cells (hBMSCs) can be induced to express retinal neuron-specific markers when co-cultured with retinal neurons, however, whether hBMSCs can differentiate into RPE-like cells in a co-culture system has not been clarified. Methods: The induction of hBMSCs into RPE-like cells was performed by combining hBMSCs and pig RPE cells in a transwell system. The biomarkers of hBMSCs-derived RPE cells were determined by quantitative RT-PCR and immunofluorescence. The function of induced cells was assayed by ELISA for secretion of neurotrophic factors. Results: Intracellular pigment granules and many RPE markers existed in hBMSCs-derived RPE cells after co-culturing with pig RPE cells for 14 days. Typical RPE functions, such as phagocytosis of photoreceptor outer segments and secretion of the trophic factors, brain-derived neurotrophic factor (BDNF) and glia-derived neurotrophic factor (GDNF), were observed in these induced cells. Conclusion: hBMSCs can be induced toward functional RPE cells simply by transwell-based co-culture with RPE cells.