IL-17 enhanced the susceptibility to fluoxetine resistance in depression via the JAK1-STAT6 signaling pathway

This study aims at investigating the role of IL-17 in fluoxetine resistance in depression.The WGCNA analysis was utilized to analyze differentially expressed genes between response to antidepressant (GRA) group and resistance to antidepressant (AR)group. Furthermore, the treatment resistance model of depression was established inChronic unpredictable mild stress (CUMS) mice administrated with fluoxetine (widely used clinical medication for the treatment of depression) according to sucrose preference rate. Depression-like behaviors in mice were detected in Control group, CUMS group, GRA group, AR group, SR1001 (Th17 differentiation inhibitor) group. Subsequently, HT22 cells were exposed to IL-17 secreted by Th17 differentiation. Transcriptome sequencing from the Control and IL-17 group was used to screen differential genes. And then HT22 cells were transfected with si-JAK1 or si-STAT6. Th17 differentiation, the integrity of the blood-brain barrier (BBB), JAK1-STAT6 signaling pathway related proteins were detected by western blot, immunocytochemistry, flow cytometric analysis, ELISA experiments, immunofluorescence, and PCR. The inhibition of Th17 differentiation and the reduction of peripheral IL-17 release could increase their sensitivity to fluoxetine resistance and relieve the depression-like behavior. This process may be associated with the JAK1-STAT6 pathway. Overall design: The HT22 cells were obtained from the Chinese Academy of Sciences (Shanghai, China). These cells were cultured in DMEM complete medium supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin. HT22 cells were cultured at 37°C in a constant temperature incubator with a 5% CO2 atmosphere. Next, the cells were exposed to IL-17. The main purpose was to validate the potential relationship between the JAK1-STAT6 signaling pathway and IL-17.