Fig. 5

The GR is specifically expressed in Müller cells and modulates glial gene expression. A Left, Confocal image of a GR labelling in retinal section of a 6-month-old mouse. Scale bar, 20 µm. Middle, STED images of a GR staining in the inner nuclear layer (INL). Müller cells were co-stained for glutamine synthetase (GLUL). Scale bars, 5 µm. Right, Line plots of mean grey values for each channel (red—GLUL as Müller cell marker residing in the cytoplasm; green—GR; blue—DAPI highlighting the DNA condensed in the nucleus). The dashed line indicates the plane of the line scan in the respective micrographs. Pink and yellow arrows indicate the orientation of data plotted in the histograms in relation to the actual line set in the micrograph. Asterisks highlight nucleoli. GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer. B Western blot to detect GR in purified retinal cell types isolated from 6-month-old mice. As the protein yield per cell population isolated per two pooled retinae is very low, the whole protein extract per cell pellet was loaded. To enable quantification of the GR band, the signals were normalised to the house keeper PDHB as done in previous studies implementing MACS-purified retinal cell types [60]. Bars represent mean ± SEM (n = 6 biological replicates per genotype). C The corticosterone level was measured in the blood plasma of diabetic and control animals at an age of 6 months via ELISA. Results of 4 control and 5 db/db mice are plotted as mean ± SEM. Unpaired t-test: *p < 0.05. D Western blot of phosphorylated GR performed on whole retinal extracts from animals 6 months of age. Bars represent mean ± SEM (n = 4 animals per genotype)