黄连味性苦寒，清热燥湿，泻火解毒，其主要活性成分小檗碱可治疗痢疾肠炎等感染性疾病，但小檗碱抗感染的机制未明。多个寒性中药单体（包括小檗碱）能激活AMPK信号途径，这与相应药材的药性可能有关联。病原微生物激活固有免疫细胞炎症小体和细胞焦亡，是机体固有免疫防御机制的关键环节。文献提示，激活AMPK可能为细菌感染及危险信号（LPS、ATP等）诱导细胞焦亡提供了扳机信号。申请人前期研究发现，小檗碱显著增强ATP诱导的活化巨噬细胞焦亡，其效应被AMPK抑制剂所抑制，提示小檗碱可能通过激活AMPK，增强被感染细胞焦亡，加速清除病原微生物，发挥抗炎除菌之功效。本课题拟利用细胞焦亡模型和细菌感染动物模型，研究小檗碱激活AMPK信号在其增强炎症小体活化和细胞焦亡进程中的作用，以及小檗碱激活AMPK、增强细胞焦亡与其抗炎除菌活性的关系，阐明小檗碱抗感染作用的机制，为科学阐释寒性中药药性理论提供有价值的证据。

Huanglian (Coptis chinensis Franch), as a bitter and cold-natured Chinese medicinal herb, is well-known for its anti-inflammatory properties: clearing heat, drying damp, purging fire, and removing toxins (in Chinese medicinal terms). Berberine, the major ingredient from Huanglian, has been used for treating dysentery and enteritis, but the underlying mechanism for its anti-bacterial infection is unclear. A number of major components from cold-natured Chinese medicinal herbs, including berberine, have been demonstrated to activate the AMPK pathway, suggesting that activation of AMPK is linked to cold-drug properties of their original herbs. Literatures have demonstrated that the activation of inflammasome and induction of pyroptosis of activated innate immune cells is a vital mechanism through which the innate immune system fights against infection, while activation of the AMPK pathway may have provided the triggering signal for the invaded pathogens or their danger molecules (such as LPS and ATP) to induce pyroptosis in the innate immune cells. Our preliminary research works demonstrate that berberine can significantly enhance ATP-induced pyroptosis in activated macrophages, whereas such an effect of berberine can be suppressed by compound C, an AMPK inhibitor. These results suggest that berberine might accelerate the clearance of invaded pathogens by enhancing the pyroptosis of the activated cells through activating the AMPK pathway, thereby displaying anti-inflammatory and bacteria-eliminating action. The present project aims to explore the anti-infection mechanism of berberine, by recruiting both cell pyroptosis models and animal bacterial infection models. We will investigate the role of AMPK activation in the action of berberine to enhance the pyroptosis, and the correlation between berberine’s anti-bacterial effect and its activity to activate AMPK and to potentiate pyroptosis. The results of this project would provide experimental basis and valuable data for the scientific interpretation of the theory on classifying cold-natured Chinese medicines.