title: Combination of retinal pigment epithelium cell-conditioned medium and photoreceptor outer segments stimulate mesenchymal stem cell differentiation toward a functional retinal pigment epithelium cell phenotype.
abstract: Recent studies have suggested that bone marrow-derived mesenchymal stem cells (BMMSCs) are capable of retinal tissue-specific differentiation but not retinal pigment epithelium (RPE) cell-specific differentiation. Photoreceptor outer segments (POS) contribute to RPE development and maturation. However, there has been no standard culture system that fosters the differentiation of BMMSCs into mature RPE cells in vitro. In this study, we investigated if the soluble factors from RPE cells and POS could differentiate BMMSCs into cells having a phenotype characteristic of RPE cells. Rat BMMSCs were separately co-cultured with RPE cells, or they were exposed to either control medium, RPE cell-conditioned medium (RPECM), POS, or a combination of RPECM and POS (RPECM-POS). After 7 days, the cells were analyzed for morphology and the expression of RPE markers (cytokeratin 8, CRALBP, and RPE65) to assess the RPE differentiation. Significantly higher pigment accumulation and increased protein expression of the three markers were seen in cells cultured in RPECM-POS than in other treated cultures. Furthermore, the RPECM-POS-treated cultures displayed ultrastructural features typical of RPE cells, expressed RPE cell functional proteins, and had the capability to phagocytose POS. Together, theses results suggest the combination of RPECM and POS stimulate BMMSCs differentiation toward a functional RPE phenotype. Our results provide the foundation for a new route to RPE regenerative therapy involving BMMSCs. Future work isolating the active agent in RPECM and POS would be useful in therapies for RPE diseases or in developing appropriately pre-differentiated BMMSCs for tissue-engineered RPE reconstruction.
authors.affiliation: Department of Ophthalmology, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing 100191, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Huang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Mingxin
authors.initials: M
authors.lastname: Ao
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Yonggen
authors.initials: Y
authors.lastname: Xu
authors.forename: Xuemin
authors.initials: X
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure; D002454:Cell Differentiation; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D010587:Phagocytosis; D010641:Phenotype; D051381:Rats; D044968:Regenerative Medicine; D055214:Retinal Photoreceptor Cell Outer Segment; D055213:Retinal Pigment Epithelium / Q000166:cytology*; D013552:Swine; D023822:Tissue Engineering
chemical_list: D000943:Antigens, Differentiation; D017077:Culture Media, Conditioned