Objective To evaluate the effect of integrin-linked kinase (ILK) in the process of retinal neovascularization induced by vascular endothelial growth factor (VEGF). Methods The ILK activities of retinal choriodal endothelial cell line RF/6A were inhibited by LY294002 or siRNA knockdown. VEGF-induced changes of cell adhesion, proliferation, migration and endothelial cell tube-formation were measured then. The in-vivo effects of ILK were also assessed by intraperitoneal injection of LY294002 into an animal model of RNV. Results The cell adhesion measurements of control group, VEGF group, VEGF＋LY294002 group and VEGF＋siRNA group were 0.0726plusmn;0.01961, 0.1137plusmn;0.02631, 0.0837plusmn;0.01503 and 0.0853plusmn;0.02454 , respectively. The difference was statistically significant between VEGF group and control group（t =4.211，Plt;0.01）, and between (VEGF＋LY294002) group or (VEGF＋siRNA) group and control group (t =3.074, 2.91，Plt;0.01). The cell proliferation results of control group, VEGF group and VEGF＋LY294002 group were 0.4162plusmn;0.1392, 0.6412plusmn;0.2420, 0.4476plusmn;0.1834 , respectively. The difference was statistically significant between VEGF group and control group（t=2.608，Plt;0.05）, and between (VEGF＋LY294002) group and VEGF group（t=2.244，Plt;0.05）.The cell migration results of control group, VEGF group and VEGF＋LY294002 group were 83.66plusmn;30.283, 248plusmn;74.748, 138.5plusmn;38.167, respectively. The difference was statistically significant between VEGF group and control group（t=5.436，Plt;0.01）, and between (VEGF＋LY294002) group and VEGF group（t=3.682，Plt;0.01）. There was no obvious tube-formation after ILK activity was inhibited or knocked down. The non-perfusion areas were increased from （62798plusmn;16995.62）mu;m2 to （84722.65plusmn;10435.01）mu;m2 after intraperitoneal injection of LY294002 into animal model of RNV, the difference was statistically significant（t=3.476，Plt;0.01）. Conclusions ILK may play an important role in the process of VEGF-induced retinal neovascularization by regulating the cellular adhesion, proliferation, migration and tube-formation, as all those cellular functions were supressed obviously after the ILK activity was inhibited by LY294002 or the ILK expression was knocked down by siRNA.
ObjectiveTo investigate the effects and mechanisms of G protein-coupled receptor 91 (GPR91) on blood-retinal barrier (BRB) in diabetic rats. MethodsA lentiviral vector of shRNA targeting rat GPR91 and scrambled shRNA were constructed. Healthy male Sprague-Dawley (SD) rats were selected in this study. The 60 rats were randomized into 4 groups and treated as follows:(1) control group (Group A, n=15), the rats received injections of an equal volume of 0.1% citrate buffer; (2) streptozocin (STZ) group (Group B, n=15), the rats received injections of STZ; (3) LV.shScrambled group (Group C, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml scrambled shRNA lentiviral particles at 2 weeks after the induction of diabetes; (4) LV.shGPR91 group (Group D, n=15), diabetic rats received an intravitreal injection of 1 μl 1×108 TU/ml pGCSIL-GFP-shGPR91 lentiviral particles. At 12 weeks after intravitreal injection, immunohistochemistry and Western blot were used to assess the expression of GPR91, p-extracellular signal-regulated kinase(ERK)1/2, t-ERK1/2, p-Jun N-terminal kinase (JNK), t-JNK, p-p38 mitogen-activated protein kinase (MAPK) and t-p38 MAPK. Haematoxylin and eosin (HE) staining and Evans blue dye were used to assess the structure and function of the retinal vessel. Immunohistochemistry enzyme-linked immunosorbent assay (ELISA) was used to test the protein level of VEGF. ResultsImmunohistochemistry staining showed that GPR91 was predominantly localized to the cell bodies of the ganglion cell layer. Western blot showed that GPR91 expression in Group D decreased significantly compared with Group C (F=39.31, P < 0.01). HE staining showed that the retina tissue in Group B and C developed telangiectatic vessels in the inner layer of retina, while the telangiectatic vessels attenuated in Group D. It was also demonstrated in Evans blue dye that the microvascular leakage in Group D decreased by (33.8±4.11)% compared with Group C and there was significant difference (F=30.35, P < 0.05). The results of ELISA showed the VEGF secretion of Group B and C increased compared with Group A and the VEGF expression in Group D was significantly down regulated after silencing GPR91 gene (F=253.15, P < 0.05).The results of Western blot indicated that compared with Group A, the expressions of p-ERK1/2, p-JNK and p-p38 MAPK were significantly upregulated (q=6.38, 2.94, 3.45;P < 0.05). Meanwhile, the activation of ERK1/2 was inhibited by GPR91 shRNA and the difference was statistically significant (F=22.50, P < 0.05). ConclusionsThe intravitreal injection of GPR91 shRNA attenuated the leakage of BRB in diabetic rats. GPR91 regulated the VEGF release and the leakage of BRB possibly through the ERK1/2 signaling pathway.