Fig. 7: EGR1 aggravates insulin resistance by transcriptionally activating LCN2 and SOCS3.

EGR1-knockdown HepG2 cells and their control cells were treated with PBS or 10 ng/mL IL-1α for 48 h and then stimulated by 100 nM insulin for 15 min. a The levels of p-IRS1, IRS1, p-AKT, t-AKT, p-p65, p65, p-STAT3, STAT3, EGR1, LCN2, SOCS3 and PTEN were determined by western blotting analysis. b The mRNA levels of EGR1, LCN2, SOCS3 and PTEN in HepG2 cells with the indicated treatments (n = 3). c PGL3.0 plasmids inserted the promoter of LCN2 or SOCS3 were co-transfected with pRL-TK plasmid into EGR1-knockdown HepG2 cells or control cells, which were treated with 10 ng/mL IL-1α for 48 h. The promoter transcriptional activity of LCN2 and SOCS3 was determined by the dual-fluorescence reporter system (n = 3). d The protein levels of EGR1 and Flag in EGR1-overexpressing HepG2 cells or control cells. e PGL3.0 plasmids inserted the promoter of LCN2 or SOCS3 were co-transfected with pRL-TK plasmid into EGR1-overexpressing HepG2 cells or control cells. The promoter transcriptional activity of LCN2 and SOCS3 was determined by the dual-fluorescence reporter system. Luciferase activity was normalized to Renilla luciferase activity (n = 3). f A schematic model for TSH triggering macrophage inflammation to exacerbate insulin resistance in SH. Data are presented as mean ± s.d. *P < 0.05, **P < 0.01, ***P < 0.001; ns, not significant (one-way ANOVA for b, c and e).