Abstract
Purpose:
Retinal detachment (RD) activates microglia/macrophages which acquire amoeboid morphology and accumulate in the subretinal space. There is up-regulation of select M1 and M2 macrophage genes in murine hyaluronic acid model of retinal detachment (HA RD). The purpose of this study was to test the hypothesis that hyaluronic acid (HA), Vitreous (VIT), or photoreceptor outer segments (PROS) induce preferential macrophage polarization and morphology changes.
Methods:
Murine microglial BV-2 cells were treated with HA, VIT, or PROS using high and low doses in serum free conditions. As controls, BV-2 cells were differentiated into an M1 or M2 phenotype with 6 hour LPS (10ng/mL) or IL-4 (20ng/mL) incubation, respectively. Total RNA was extracted at 12 hours and real time PCR was performed for M1 (Ccl2, Nos2, Cxcl10, Tnfa, Il1b) and M2 genes (Mrc1, Arg1). Cell morphology was determined from phase contrast photographs of cultured cells at 6 and 12 hours.
Results:
At 12 hours, VIT induced Arg1 M2 gene expression, 2.3-fold in low-dose and 29.9 fold in high-dose conditions. High-dose PROS also increased Arg1 expression by 4-fold. HA did not induce Arg1 gene expression. Il1b was induced by PROS exposure (4.7-9.1-fold), with lower levels induced by VIT and HA. Ccl2, Nos2, Cxcl10, Tnfa, and Il1b were induced in LPS-treated cells but not IL-4 treated cells or controls. Mrc1 and Arg1 were induced in IL-4-treated cells. Cell morphology was more spindle-shaped in HA, VIT, IL-4, and LPS-treated cells compared to controls. Filopodia were broader in HA and VIT conditions and narrow in LPS. PROS induced an amoeboid morphology.
Conclusions:
Select M1/M2 gene expression and morphology changes were induced in BV-2 cells by critical components of RD, including vitreous and photoreceptor outer segments.
Keywords: 697 retinal detachment •
595 microglia •
533 gene/expression