Influence of curcumin on LPS-induced autophagy in corneal stromal cells by regulating PI3K/AKT/mTOR signaling pathway
Objective:To investigate influences of curcumin on LPS-induced autophagy in corneal stromal cells by regulating phosphatidylinositol 3-kinase(PI3K)/serine-threonine kinase(AKT)/mammalian target of rapamycin(mTOR)signaling pathway.Methods:Mouse corneal stromal cells were grouped into control group,LPS group(1 μg/μl LPS),L-Cur group(15 μmol/L curcumin),M-Cur group(30 μmol/L curcumin),H-Cur group(50 μmol/L curcumin),and H-Cur+740Y-P group(50 μmol/L curcumin+10 μmol/L PI3K activator 740Y-P).MTT was applied to detect effect of curcumin on corneal stromal cytotoxicity and cell viability;ELISA was applied to detect levels of inflammatory factors in corneal stromal cells;immunofluorescence staining was applied to detect levels of Beclin1 and LC3 in mouse corneal stromal cells;Western blot was applied to detect expressions of autophagy-related proteins and pathway-related proteins in corneal stromal cells.Results:0~90 μmol/L curcumin had no obvious toxicity to corneal stromal cells.Compared with control group,A570 nm,levels of Beclin1 and LC3Ⅱ/Ⅰ in LPS group were obviously decreased(P<0.05),levels of IL-6,IL-8,p-PI3K/PI3K,p-AKT/AKT and p-mTOR/mTOR were obviously increased(P<0.05);compared with LPS group,A570 nm,levels of Beclin1 and LC3Ⅱ/Ⅰ in L-Cur group,M-Cur group,H-Cur group were obviously increased in turn(P<0.05),levels of IL-6,IL-8,p-PI3K/PI3K,p-AKT/AKT and p-mTOR/mTOR were obviously decreased in turn(P<0.05);H-Cur+740Y-P eliminated beneficial effect of curcumin on corneal stromal cells.Conclusion:Curcumin may promote LPS-induced autophagy in corneal stromal cells by down-regulating PI3K/AKT/mTOR signaling pathway.