Abstract
We investigated the expression profile of monocyte chemoattractant protein‐1 (MCP‐1) in human retinal pigment epithelial (RPE) cells under different culture conditions and evaluated the molecular mechanism responsible for MCP‐1 gene expression in RPE cells. After cellular confluence, total RNA was extracted and used for RT‐PCR. Medium conditioned by RPE was used for ELISA and Western blotting. The result showed that RPE cells cultured on plastic expressed MCP‐1 constitutively in the absence of any stimuli. On the other hand, growing human RPE on laminin‐coated flasks instead of plastic reduced the production of MCP‐1. In the RPE cells cultured on plastic, IκB was degraded and A20 protein increased concomitantly. MCP‐1 upregulation in RPE cells on plastic was attenuated by the addition of MG‐132, a proteasome inhibitor. Also, the addition of pyrolidine dithiocarbonate (PDTC) and hypoxic conditions (0.5% O~2~) decreased MCP‐1 production in these cells. These findings suggested that the expression profile of MCP‐1 is regulated by phenotypic alterations of the RPE cells. And the increased MCP‐1 expression in RPE cells cultured on plastic is caused via spontaneous activation of NFκB induced by susceptibility to oxidative stress. J. Cell. Physiol. 197: 77–85, 2003© 2003 Wiley‐Liss, Inc.