Abstract
Purpose :
Endogenous danger signals released from necrotic cells contribute to retinal sterile inflammation. We have previously investigated the effects of necrotic cell extracts prepared from ARPE-19 human retinal pigment epithelial cells (ANCE) on the release of pro-inflammatory cytokines and chemokines by healthy ARPE-19 cells. To reveal pathological activation of RPE in sterile inflammation, we have now investigated the effects of necrotic cell extracts on the secretion of VEGF from intact PRE and the effect of growth factors derived from necrotic RPE cells on the VEGF regulation.
Methods :
Necrotic cell extracts prepared from ARPE-19 human retinal pigment epithelial cells (ANCE) were prepared by subjection of ARPE-19 cells to freeze-thaw cycles. The release of VEGF-A, FGF2 and PDGF-BB from ARPE-19 cells was measured with a multiplex assay system or enzyme-linked immunosorbent assays. To investigate the effect of growth factors derived from ANCE, VEGF receptor 2 inhibitor SU1498, PDGF receptor inhibitor AG1296, FGF receptor inhibitor BGJ398 and these triple tyrosine kinase receptor inhibitor BIBF1120 were used. The expression of extracellular signal-regulated kinase 1/2 (Erk1/2), phospho-Erk1/Erk2, signal transducer and activator of transcription 3 (STAT3), phospho-STAT3, Ark, phospho-Ark, beta actin were examined by immunoblot analysis.
Results :
We found that ANCE stimulated the release of VEGF-A from ARPE-19 cells. ANCE-induced VEGF secretion was not inhibited by SU1498, AG1296 or BGJ398. Whereas, the VEGF secretion was inhibited by BIBF1120 in a concentration-dependent manner. Furthermore, ANCE induced the phosphorylation of Erk1/2 and phosphorylation of STAT3 in ARPE-19 cells, and BIBF1120 suppress these phosphorylation.
Conclusions :
We demonstrated that VEGF secretion from healthy RPE was up-regulated through Erk1/2 and STAT3 signaling pathway by growth factors PDGF, FGF and VEGF derived from necrotic RPE cells. We suggest that endogenous danger signals released from necrotic cells could pathologically induce VEGF secretion in RPE.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.