Probiotic Bacillus amyloliquefaciens SC06 induces Autophagy to Protect against Pathogens in Macrophages

【作者】 吴艳萍； Yang Wang； Hai Zou； Baikui Wang； Qiming Sun； Aikun Fu； Yuanyuan Wang； Yibing Wang； Xiaogang Xu； 李卫芬；

【Author】 Yanping Wu;Yang Wang;Hai Zou;Baikui Wang;Qiming Sun;Aikun Fu;Yuanyuan Wang;Yibing Wang;Xiaogang Xu;Weifen Li;Key Laboratory of Molecular Animal Nutrition of Ministry of Education,Institute of Feed Science,College of Animal Sciences,Zhejiang University;Department of Cardiology,Zhejiang Provincial People’s Hospital;Department of Biochemistry,School of Medicine,Zhejiang University;

【机构】 浙江大学动物科学学院饲料科学研究所； Key Laboratory of Molecular Animal Nutrition of Ministry of Education,Institute of Feed Science,College of Animal Sciences,Zhejiang University； Department of Cardiology,Zhejiang Provincial People’s Hospital； Department of Biochemistry,School of Medicine,Zhejiang University；

【摘要】 Probiotics are increasingly applied in popularity in both humans and animals.Decades of research has revealed their beneficial effects,including the immune modulation in intestinal pathogens inhibition.Autophagy—a cellular process that involves the delivery of cytoplasmic proteins and organelles to the lysosome for degradation and recirculation— is essential to protect cells against bacterial pathogens.However,the mechanism of probiotics-mediated autophagy and its role in the elimination of pathogens are still unknown.Here,we evaluated Bacillus amyloliquefaciens SC06(Ba)-induced autophagy and its antibacterial activity against Escherichia coli in RAW264.7 cells.Western blotting and confocal laser scanning analysis showed that Ba stimulated autophagy in a dose-and time-dependent manner.Ba-induced autophagy was found to play a role in the elimination of intracellular bacteria when RAW264.7 cells were challenged with Escherichia coli(E.coli).Ba induced autophagy by increasing the expression of Beclin1 and Atg5-Atg12-Atg16 complex,but not the AKT/mTOR signaling pathway.Moreover,Ba pretreatment attenuated the activation of JNK in RAW264.7 cells during E.coli infection,further indicating a protective role for probiotics via modulating macrophage immunity.The above findings highlight a novel mechanism underlying the antibacterial activity of probiotics.This study enriches the current knowledge on probiotic-mediated autophagy,and provides a new perspective on the prevention of bacterial infection in intestine,which further the application of probiotics in food products.更多还原

【Abstract】 Probiotics are increasingly applied in popularity in both humans and animals.Decades of research has revealed their beneficial effects,including the immune modulation in intestinal pathogens inhibition.Autophagy—a cellular process that involves the delivery of cytoplasmic proteins and organelles to the lysosome for degradation and recirculation— is essential to protect cells against bacterial pathogens.However,the mechanism of probiotics-mediated autophagy and its role in the elimination of pathogens are still unknown.Here,we evaluated Bacillus amyloliquefaciens SC06(Ba)-induced autophagy and its antibacterial activity against Escherichia coli in RAW264.7 cells.Western blotting and confocal laser scanning analysis showed that Ba stimulated autophagy in a dose-and time-dependent manner.Ba-induced autophagy was found to play a role in the elimination of intracellular bacteria when RAW264.7 cells were challenged with Escherichia coli(E.coli).Ba induced autophagy by increasing the expression of Beclin1 and Atg5-Atg12-Atg16 complex,but not the AKT/mTOR signaling pathway.Moreover,Ba pretreatment attenuated the activation of JNK in RAW264.7 cells during E.coli infection,further indicating a protective role for probiotics via modulating macrophage immunity.The above findings highlight a novel mechanism underlying the antibacterial activity of probiotics.This study enriches the current knowledge on probiotic-mediated autophagy,and provides a new perspective on the prevention of bacterial infection in intestine,which further the application of probiotics in food products.更多还原