KLF4调控TRIB1转录介导小胶质细胞极化改善小鼠抑郁样行为的机制研究OA

Objective:To explore the role and mechanism of Krüppel-like factor 4(KLF4)in regula-ting microglial polarization to attenuate depressive-like behaviors in mice.Methods:Ten C57BL/6 mice were randomly divided into control group and model group,with 5 mice in each group,A mouse depression model was established in the model group by chronic unpredictable stress induction,RT-qPCR,Western blot and immunohistochemical staining were used to detect the expression of KLF4 and trimer protein 1(TRIB1)in hippocampal tissue,dual luciferase reporter gene experiment combined with chromatin immunoprecipitation(ChIP)was used to verify the regulatory effect of KLF4 on TRIB1.Thirty-two C57BL/6 mice were randomly divided into control group,model group,KLF4-overexpressing lentivirus(oe-KLF4)group and KLF4-over-expressing lentivirus+TRIB1 knockout lentivirus(oe-KLF4+sh-TRIB1)group,the depression model was in-duced in the other three groups of mice except for the control group,the KLF4-overexpressing lentivirus and TRIB1 knockout lentivirus were injected into the lateral ventricle.One week later,sucrose preference test,tail suspension test and forced swimming test were performed to detect the depressive-like behaviors of mice,HE staining was used to observe the pathological changes in the hippocampal tissue,ELISA experiment was used to detect the levels of proinflammatory cytokines including interleukin(IL)-1β,IL-6,and tumor necrosis factor-α(TNF-α)in hippocampal tissue,immunohistofluorescence double staining was used to detect the ex-pression of M1 microglia marked by ionized calcium-binding adapter molecule1(Iba1)+/CD86+and M2 mi-croglia marked by Iba-1+/CD206+in the hippocampus,western blot was used to determine the expression levels of proteins related to the protein kinase B(Akt)signaling pathway in the hippocampal tissues.Results:After model establishment in mice,the relative mRNA and protein expression levels of KLF4 and TRIB1 in hippocampal tissue were downregulated,the positive staining of KLF4 and TRIB1 was also reduced,the lucif-erase activity of TRIB1 WT reporter plasmid in the oe-KLF4 group was higher than that in the oe-NC group,and the relative enrichment of TRIB1 in the Anti-KLF4 group was higher than that in the Anti-IgG group(P＜0.05).Compared with the model group,the sucrose consumption rate of mice in the oe-KLF4 group was in-creased,and the immobility time in the tail suspension test and the forced swimming test were shortened,pathological changes such as decreased number of neurons,karyopyknosis or karyolysis and cytoplasmic vacu-olization were significantly improved,the contents of IL-1 β,IL-6,and TNF-α in hippocampal tissue were reduced,the fluorescence intensity of the M1 marker Iba-1+/CD86+was weakened,whereas that of the M2 marker Iba-1+/CD206+was enhanced,and the relative protein expression levels of p-Akt/Akt and p-Stat3/Stat3 were upregulated(P＜0.05);Compared with the oe-KLF4 group,the sucrose consumption rate of mice in the oe-KLF4+sh-TRIB1 group was reduced,the immobility time in the tail suspension test and the forced swimming test was prolonged,the pathological damage of hippocampal tissue was aggravated,the contents of IL-1β,IL-6 and TNF-α were increased,the fluorescence intensity of the M1 marker Iba-1+/CD86+was enhanced,whereas that of the M2 marker Iba-1+/CD206+was weakened,and the relative protein expression levels of p-Akt/Akt and p-Stat3/Stat3 were downregulated(P＜0.05).Conclusion:KLF4 can promote the polarization of microglia to M2 type by upregulating TRIB1 expression,thereby improving the depressive-like behaviors in mice.