Abstract
Purpose:
The transplantation of embryonic stem cell-derived polarized RPE monolayers to restore the lost or dysfunctional RPE is a promising new treatment for age-related macular degeneration (AMD), however, immune rejection remains to be the biggest challenge for long term survival of those implanted allogeneic cells. Dexamethasone (DEX), a widely used synthetic corticosteroid, is known to inhibit allogeneic immune rejection, but also promote cell death in several cell types. This study is to investigate the effect and potential side-effect of DEX on polarized RPE cells derived from the H9 embryonic stem cell line (H9-RPE).
Methods:
RPE cells derived from H9 human embryonic stem cells were cultured on substrates for 4 weeks to form a polarized monolayer; the polarized RPE monolayer was then treated with different concentrations (0, 10, 100 nM) of DEX for a month. Live/dead cell staining, quantitative PCR, immunofluorescent staining, and ELISA were used to examine the cell viability, the changes of mRNA and protein expression levels of RPE signature genes and apoptosis related genes.
Results:
After DEX treatment, significantly increased cell death was observed in non-polarized H9RPE cells, but not in polarized H9RPE cells, as compared to non-DEX treated corresponding control cells. The polarized RPE cells kept their hexagonal shape and integrity of tight junctions after long term DEX treatment. The expression level of RPE signature genes, such as RPE65, PMEL and PEDF had no significant difference in DEX treated polarized H9RPE cells, as compared to non-DEX treated control cells.
Conclusions:
Although it may increase non-polarized RPE cell death, DEX does not impose adverse effects on polarized RPE cells.
Keywords: 412 age-related macular degeneration •
721 stem cells •
695 retinal degenerations: cell biology