Abstract
Purpose:
Inflammation is considered to be an important part of the process leading to age-related macular degeneration (AMD). We have previously shown that retinal pigment epithelial (RPE) cells increase basolateral secretion of several chemokines such as CCL2, CCL5, CXCL8, CXCL9, CXCL10 and CXCL11 upon co-culture with activated T cells. Since it is reported that more macrophages accumulate with age in the choroid and more macrophages are found near drusen of AMD patients, we hypothesize that stressed RPE cells play a role in the attraction of monocytes from the periphery into the subretinal space.
Methods:
The human ARPE-19 cell line was cultured in membrane inserts. T cells were purified from fresh whole blood and added under the insert (basolateral co-culture) with CD3/CD28-stimulation. After 48 hours the basolateral supernatant was collected. For the migration assay, CD14+ monocytes purified from healthy donors were added to the upper chamber of a transwell plate, and in the lower chamber the different basolateral supernatants were added. The plate was incubated for 2.5 hours and the number of migrated cells was counted with flow cytometry.
Results:
Although RPE cells upregulate basolateral secretion of a number of chemoattractants upon co-culture with activated T cells, they do not attract more monocytes compared to unstimulated RPE cells.
Conclusions:
This increased RPE chemokine secretion does not lead to an increased monocyte attraction. This suggests that RPE cells concomitantly produce factors which inhibit monocyte migration. Since higher numbers of macrophages have been reported in the choroid/retina of AMD patients, other cells present in the choroid/retina might be involved in the attraction of monocytes.
Keywords: 412 age-related macular degeneration •
557 inflammation •
701 retinal pigment epithelium