Establishment of conditionally immortalized rat retinal pericyte cell lines (TR-rPCT) and their application in a co-culture system using retinal capillary endothelial cell line (TR-iBRB2).

The purpose of this study was to establish and characterize a retinal pericyte cell line from retinal capillaries of transgenic rats harboring the temperature-sensitive simian virus 40 large T-antigen gene (tsA58 Tg rat), and to apply this to the co-culture with a retinal capillary endothelial cell line. The conditionally immortalized rat retinal pericyte cell lines (TR-rPCTs), which express a temperature-sensitive large T-antigen, were obtained from two tsA58 Tg rats. These cell lines had a multicellular nodule morphology and reacted positively with von Kossa staining, a marker of calcification. TR-rPCTs cells expressed mRNA of pericyte markers such as rat intercellular adhesion molecule-1, platelet-derived growth factor-receptor beta, angiopoietin-1, and osteopontin. Western blot analysis indicated that alpha-smooth muscle actin (alpha-SMA) was expressed in TR-rPCT3 and 4 cells. In contrast, alpha-SMA was induced by transforming growth factor-beta1 and its enhancement was reduced by basic fibroblast growth factor in TR-rPCT1 and 2 cells. When TR-rPCT1 cells were cultured with a rat retinal endothelial cell line (TR-iBRB2) in a contact co-culture system, the number of TR-iBRB2 cells were significantly reduced in comparison with that of a single culture of TR-iBRB2 cells, suggesting that physical contact between pericytes and retinal endothelial cells is important for the growth of retinal endothelial cells. In conclusion, conditionally immortalized retinal pericyte cell lines were established from tsA58 Tg rats. These cell lines exhibited the properties of retinal pericytes and can be applied in co-culture systems with a retinal capillary endothelial cell line.