RESUMEN
Diabetic retinopathy (DR) as a retinal neovascularization-related disease is one of the leading causes of irreversible blindness in patients. The goal of this study is to determine the role of a G-protein-coupled chemoattractant receptor (GPCR) FPR2 (mouse Fpr2) in the progression of DR, in order to identify novel therapeutic targets. We report that Fpr2 was markedly upregulated in mouse diabetic retinas, especially in retinal vascular endothelial cells, in associated with increased number of activated microglia and Müller glial cells. In contrast, in the retina of diabetic Fpr2 -/- mice, the activation of vascular endothelial cells and glia was attenuated with reduced production of proinflammatory cytokines. Fpr2 deficiency also prevented the formation of acellular capillary during diabetic progression. Furthermore, in oxygen-induced retinopathy (OIR) mice, the absence of Fpr2 was associated with diminished neovasculature formation and pathological vaso-obliteration region in the retina. These results highlight the importance of Fpr2 in exacerbating the progression of neuroglial degeneration and angiogenesis in DR and its potential as a therapeutic target.
RESUMEN
Activation of P2X7R is linked to the occurrence and development of glaucoma. The present study concentrated on the activated P2X7R-NLRP3 pathway underlying the retinal microglia in retinal ganglion cells (RGCs) in chronic ocular hypertension (COH). Mouse COH model was set up to investigate the changes of P2X7R-NLRP3 inflammatory pathway in vivo. Primary microglia cells and primary RGCs were cultured and purified in vitro experiments. The expression of P2X7R, NLRP3, CASP-1, and ASC was detected and analyzed using Western blot, Quantitative polymerase chain reaction (qPCR) and immunofluorescence. Hoechst stains labeled nucleus to count microglia cells after experimental treatment. RGCs survival rate was examined utilizing LIVE/DEAD viability kit. The level of cytokines was measured by qPCR and enzyme-linked immunosorbent assay (ELISA). Consequently, the expression of P2X7R, NLRP3, CASP-1, and ASC was raised in COH mice retina. The number of microglia cells was increased after addition of BzATP, the agonist of P2X7R, to the culture medium of primary rat microglia cells. However, survival rates of RGCs decreased after addition of conditioned media to the RGC cultures. A438079 (100⯵M), the inhibitor of P2X7R, and Mcc950 (1⯵M), the inhibitor of NLRP3, blocked the effect of P2X7R activation in rat retinal microglia cells. Both inhibitors attenuated RGC death with the treatment of retina microglia cell conditioned medium (MCM). The production of some pro-inflammatory cytokines, such as TNF-α, CXCL-1, CSF-1, IL-6, IL-1ß, and IL-18 was increased markedly with the activation of P2X7R in microglia. However, the effect suffered as a result of A438079 and partially inhibited by Mcc950. These data suggested a role of P2X7R -NLRP3 pathway in activated retinal microglia cell-mediated RGC damages in COH.
