Curcumin induces the autophagy of Mycobacterium tuberculosis-infected macrophages through PI3K/Akt/mTOR pathway
10.3760/cma.j.cn112309-20240102-00002
- VernacularTitle:姜黄素基于PI3K/Akt/mTOR通路诱导结核分枝杆菌感染巨噬细胞自噬
- Author:
Xiaomei LUO
1
;
Xiaoqun HAN
;
Qin DENG
;
Nanyan FU
;
Zhixing ZHOU
;
Siyu HUANG
Author Information
1. 宜春学院化学与生物工程学院，宜春 336000
- Publication Type:Journal Article
- Keywords:
Mycobacterium tuberculosis;
Autophagy;
PI3K;
Akt;
mTOR;
Curcumin
- From:
Chinese Journal of Microbiology and Immunology
2025;45(1):64-71
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the effect of curcumin on phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway on the autophagy of Bacille Calmette-Guérin (BCG)-infected macrophages.Methods:The infection model was established by infecting THP-1-derived macrophages with BCG. Five groups were involved in this study, which were control group, BCG group, BCG+ curcumin group, BCG+ curcumin+ IGF-1(PI3K agonist) group, and BCG+ curcumin+ LY294002 (PI3K inhibitor) group. The fluorescence intensity of autophagosomes was observed under fluorescence microscope using the fluorescent dye monodansylcadaverine (MDC staining). The expression of PI3K, Akt, mTOR, phospho-PI3K (p-PI3K), phospho-Akt (p-Akt), phospho-mTOR (p-mTOR), microtubule-associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ), and Beclin-1 at protein level were detected by Western blot. Colony forming unit was used to detect macrophage load. Multiple independent, normal, and homogeneous data were compared using one-way analysis of variance, and pairwise comparisons were conducted using LSD test.Results:BCG infection significantly decreased the fluorescence intensity of autophagosomes, and the expression of autophagy marker proteins LC3-Ⅱ and Beclin-1 ( P<0.05), but increased the expression of p-PI3K, p-Akt, and p-mTOR ( P<0.05). Curcumin increased the fluorescence intensity of autophagosomes and enhanced the expression of LC3-Ⅱ and Beclin-1 proteins in a concentration-dependent manner ( P<0.05). Besides, curcumin inhibited the expression of p-PI3K, p-Akt, and p-mTOR ( P<0.05). The PI3K agonist IGF-1 reversed the above effects of curcumin. Compared with the BCG+ curcumin group, the fluorescence intensity of autophagosomes and the expression of LC3-Ⅱ and Beclin-1 proteins were further increased ( P<0.05), while the expression of p-PI3K, p-Akt and p-mTOR was further decreased ( P<0.05) in the BCG+ curcumin+ LY294002 group. Compared with the BCG group, the bacterial loads in the BCG+ curcumin group and the BCG+ curcumin+ LY294002 group decreased significantly ( P<0.05), while the bacterial load in the BCG+ curcumin+ IGF-1 group increased significantly ( P<0.05). Conclusions:Curcumin can promote the autophagy of BCG-infected macrophages, which contributes to the clearance of Mycobacterium tuberculosis by macrophages. Part of the mechanism may be related to the inhibition of PI3K/Akt/mTOR pathway.
