Abstract
Purpose: :
To evaluate the potential differentiation of rat mesenchymal stem cells (MSCs) toward retinal pigment epithelium (RPE) cells.
Methods: :
Retinal pigment epithelium cells and MSCs were isolated from the 2-week-old pigmented Brown Norway rats. MSC markers were detected by flow cytometry. The 2 to 3 passage MSCs were used for differentiation. Adipogenic and osteogenic differentiation potential of MSCs was observed. MSCs were cultured with RPE cells using Millicell inserts or with different mixing proportion of RPE cell culture supernatants. Cellular morphology of induced MSCs was observed. The induction efficiency was evaluated by examined the expression of markers of RPE cells using immunofluorescence. Porcine rod outer segments (ROS) were purified by sucrose gradient centrifugation and labeled with 10 ug/ml fluorescein isothiocyanate. Labeled-ROS added to RPE cells, MSCs and induced cells for 3, 5, 12 and 24 hours. ROS binding and internalization were quantized with a fluorescence assay.
Results: :
The cultured MSCs expressed MSC surface markers and featured multiple lineage differentiation. Only in the supernatants culture, the obvious pigment granules appeared on MSCs leading to several pigment cell groups by subsequent passages. The evaluation of induction efficiency demonstrated that the difference of RPE-differentiation of MSCs between the culture supernatants and co-cultures was significant. Treatment with the supernatants enhanced the expression of keratin and RPE65 compared to the co-cultures. Although slightly lower than RPE cells, the mean phagocytotic activity of MSCs-RPE-like cells was significantly higher than MSCs. The presence of 20 percent RPE culture supernatants in the culture medium strongly promoted RPE differentiation.
Conclusions: :
These results demonstrate that MSCs may be selectively directed to a RPE cell fate. The MSCs-RPE like cells may be a good candidate of new cell source for the RPE transplantation, which provides a feasible therapy strategy for RPE associated diseases.
Keywords: retinal pigment epithelium • differentiation