抑郁症是最常见的精神疾病之一。单胺递质理论表明,神经递质参与抑郁症的机制;然而,对5-羟色胺产生的调节仍不清楚.我们先前表明,Ahi1敲除(KO)小鼠表现出抑郁样行为,并伴有脑5-羟色胺的显着降低。
在本研究中,westernblot,基因敲低,免疫荧光,双荧光素酶报告分析,和挽救试验用于检测雄性应激小鼠和雄性Ahi1KO小鼠大脑中Ahi1/GR/ERβ/TPH2通路的变化,以解释抑郁症样行为的发病机理。此外,测量雄性和雌性小鼠血液和大脑中的E2水平,以研究对ERβ/TPH2通路的影响,并揭示抑郁样行为中性别差异现象的机制。
我们发现,在雄性应激小鼠和雄性Ahi1KO小鼠中,产生5-羟色胺的途径-ERβ/TPH2途径受到抑制。我们进一步证明,糖皮质激素受体(GR)作为转录因子与包含糖皮质激素反应元件的ERβ启动子结合,并抑制ERβ的转录。我们最近的研究表明,Ahi1在应激时调节GR的核易位,因此提出了用于5-羟色胺生产的Ahi1/GR/ERβ/TPH2途径。有趣的是,雌性Ahi1KO小鼠没有表现出抑郁行为,表明与雄性小鼠相比,抑郁行为的性别差异。此外,我们发现在雄性和雌性小鼠中血清17β-雌二醇(E2)水平没有改变;雄性而非雌性Ahi1KO小鼠的大脑E2水平显着降低。Further,ERβ激动剂LY-500307增加TPH2表达和5-HT产生。因此,Ahi1和E2均调节ERβ/TPH2途径,并涉及脑5-羟色胺产生和抑郁行为的性别差异。
总之,尽管目前尚不清楚Ahi1如何控制大脑中的E2分泌,我们的研究结果表明,Ahi1通过大脑中的GR/ERβ/TPH2通路调节5-羟色胺的产生,并可能涉及对抑郁行为性别差异的调节.视频摘要。
Depression is one of the most common psychiatric diseases. The monoamine transmitter theory suggests that neurotransmitters are involved in the mechanism of depression; however, the regulation on serotonin production is still unclear. We previously showed that Ahi1 knockout (KO) mice exhibited depression-like behavior accompanied by a significant decrease in brain serotonin.
In the present study, western blot, gene knockdown, immunofluorescence, dual-luciferase reporter assay, and rescue assay were used to detect changes in the Ahi1/
GR/ERβ/TPH2 pathway in the brains of male stressed mice and male Ahi1 KO mice to explain the pathogenesis of depression-like behaviors. In addition, E2 levels in the blood and brain of male and female mice were measured to investigate the effect on the ERβ/TPH2 pathway and to reveal the mechanisms for the phenomenon of gender differences in depression-like behaviors.
We found that the serotonin-producing pathway-the ERβ/TPH2 pathway was inhibited in male stressed mice and male Ahi1 KO mice. We further demonstrated that glucocorticoid receptor (
GR) as a transcription factor bound to the promoter of ERβ that contains glucocorticoid response elements and inhibited the transcription of ERβ. Our recent study had indicated that Ahi1 regulates the nuclear translocation of
GR upon stress, thus proposing the Ahi1/
GR/ERβ/TPH2 pathway for serotonin production. Interestingly, female Ahi1 KO mice did not exhibit depressive behaviors, indicating sexual differences in depressive behaviors compared with male mice. Furthermore, we found that serum 17β-estradiol (E2) level was not changed in male and female mice; however, brain E2 level significantly decreased in male but not female Ahi1 KO mice. Further, ERβ agonist LY-500307 increased TPH2 expression and 5-HT production. Therefore, both Ahi1 and E2 regulate the ERβ/TPH2 pathway and involve sexual differences in brain serotonin production and depressive behaviors.
In conclusion, although it is unclear how Ahi1 controls E2 secretion in the brain, our findings demonstrate that Ahi1 regulates serotonin production by the
GR/ERβ/TPH2 pathway in the brain and possibly involves the regulation on sex differences in depressive behaviors. Video Abstract.