Figure 1 of Li, Mol Vis 2014; 20:1109-1121.


Figure 1. Succinate was increased in streptozotocin (STZ)-induced diabetic rats, and G protein-coupled receptor 91 (GPR91) was predominantly increased in retinal ganglion cells (RGCs). A: Retinal levels of succinate were detected by gas chromatography-mass spectrometry (GC-MS) analysis in non-diabetic rats and diabetic rats at 1 week, 2 week, 4 week, 8 week, and 12 week after STZ injection. The levels of succinate were markedly increased in fresh retinal samples from diabetic rats compared with non-diabetic retinas. Each column denotes the mean ± standard deviation (SD; n = 6). B: Western blot analysis of the GPR91 protein in samples from each group. C: The expression of GPR91 did not change significantly between the non-diabetic and diabetic rat retinas. Each column denotes the mean ± SD (n = 6). D: Immunofluorescence localization of GPR91 in the retina showing pronounced expression in the ganglion cell layer, and to a lesser extent, to cells of the inner nuclear layer and retinal pigment epithelium. GPR91 protein levels were significantly downregulated in rats transduced with GPR91 shRNA lentiviral particles compared to those transduced with the scrambled shRNA. GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; RPE, retinal pigment epithelium. Scale bar, 100 μm. E: The immunofluorescence localization of GPR91 in the retina was not consistent with an endothelial cell. Scale bar, 100 μm. F: Western blot analysis of the GPR91 protein in samples from each group. Four week diabetic rats were treated with scrambled shRNA lentiviral particles or GPR91 shRNA lentiviral particles intravitreally. G: GPR91 protein levels were significantly downregulated in rats transduced with GPR91 shRNA lentiviral particles compared to those transduced with the scrambled shRNA. Each column denotes the mean ± SD (n = 6). H: The nonfasting blood glucose was detected in the 2 week to 14 week diabetic rats and non-diabetic rats. The nonfasting blood glucose was markedly higher in the diabetic rats than in the non-diabetic rats, and local GPR91 knockdown produced no effect on hyperglycemia in diabetic rats. Each node denotes the mean ± SD (n = 6). I: The bodyweights were recorded in the same period (from 2 week to 14 week) for the diabetic rats and non-diabetic rats. The bodyweights were significantly lower in the diabetic rats than the non-diabetic rats. Each node denotes the mean ± SD (n = 6). **p<0.01 versus control. ##p<0.01 versus LV.shScrambled group rats.