Figure 4: SGK-1 mediates the glucocorticoid-regulated diurnal oscillations in the threshold of mechanical allodynia in PSL mice. | Nature Communications

Figure 4: SGK-1 mediates the glucocorticoid-regulated diurnal oscillations in the threshold of mechanical allodynia in PSL mice.

From: Glucocorticoid regulation of ATP release from spinal astrocytes underlies diurnal exacerbation of neuropathic mechanical allodynia

Figure 4

(a,b) Diurnal oscillations in the spinal expression of SGK-1 is dependent on glucocorticoid (means±s.e.m.; n=5). Significant time-dependent variations were observed in the levels of Sgk-1 mRNA and its protein in the contralateral (Contra.) (F5,24=33.233, P<0.001 for mRNA; F5,24=4.808, P=0.006 for protein; ANOVA) and the ipsilateral (Ipsi.) sides (F5,24=14.996, P<0.001 for mRNA; F5,24=4.591, P=0.007 for protein; ANOVA). *P<0.05 significant difference between two time points (F3,16=105.464, P<0.001 for mRNA; F3,16=670.562, P<0.001 for protein; ANOVA with Tukey–Kramer’s PHT). (c) The temporal binding profiles of the GCR to the Sgk-1 promoter in the spinal cords of sham+PSL and ADX+PSL male mice. GCR and RNA polymerase 2 (POL2) in the nuclear fraction of spinal cords were detected by western blotting (WB). Immunoprecipitates (IP) with anti-GCR antibodies were subjected to a PCR analysis. Solid line arrows in the upper panel represent PCR amplification areas. Data are representative of three independent experiments. Full-size images of WB are presented in Supplementary Fig. 13. (d) The intrathecal (i.th.) injection of the SGK-1 inhibitor GSK650394 (0.5 nmol per mouse) alleviates pain hypersensitivity of the ipsilateral hindpaw in male sham+PSL mice and suppresses of spinal ATP release (means±s.e.m.; n=5), **P<0.01, *P<0.05 significantly different from vehicle-treated groups at the corresponding time points (F9,40=8.876, P<0.001 for pain threshold, F3,16=12.454, P<0.001 for ATP release; ANOVA with Tukey–Kramer’s PHT). (e) The SGK-1 inhibitor GSK650394 (0.5 pmol per mouse, i.th.) prevents CORT (30 mg kg−1, s.c.)-induced pain hypersensitivity of the ipsilateral hindpaw in male ADX+PSL mice and suppresses spinal ATP release (means±s.e.m.; n=5) **P<0.01, *P<0.05 significantly different from the other groups (F23,96=3.599, P<0.001 for pain threshold, F7,36=5.735, P<0.001 for ATP release; ANOVA with Tukey–Kramer’s PHT). The administration time of CORT or GSK650394 was set at ZT10. All experiments were performed on day 7 after nerve injury.

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