TY - JOUR
T1 - Pseudomonas aeruginosa promotes autophagy to suppress macrophage-mediated bacterial eradication
AU - Wu, Yongjian
AU - Li, Dandan
AU - Wang, Yi
AU - Chen, Kang
AU - Yang, Kun
AU - Huang, Xi
AU - Zhang, Yuanqing
AU - Wu, Minhao
N1 - Funding Information:
This work was supported by grants National Natural Science Foundation of China ( 31200662 , 31370868 , 31470877 , 81401645 , 81172811 , 81261160323 ), the 111 Project (No. B13037 ), Guangdong Innovative Research Team Program ( 2009010058 , 2011Y035 ), Specialized Research Fund for the Doctoral Program of Higher Education of China ( 20120171120064 ), Guangdong Natural Science Foundation ( 10251008901000013 , S2012040006680 ), Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (No. 2009 ), National Science and Technology Key Projects for Major Infectious Diseases ( 2013ZX10003001 ).
Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - Objectives To explore the role of autophagy on macrophage-mediated phagocytosis and intracellular killing of Pseudomonas aeruginosa (PA), a common extracellular bacterium which often causes various opportunistic infections. Methods Macrophages were infected with PA or stimulated with zymosan bioparticles. Autophagy was tested by fluorescent microscopy and Western blot for LC3. Phagocytosis and killing efficiency were assessed by plate count assay, flow cytometry or immunofluorescent staining. Phagocytic receptor expression, ROS generation and NO production were examined by PCR, flow cytometry and Griess reaction, respectively. Results PA infection induced autophagy activation in both mouse and human macrophages. Induction of autophagy by rapamycin or starvation significantly inhibited PA internalization by downregulating phagocytosis receptor expression, and suppressed intracellular killing of PA via reducing ROS and NO production in macrophages. While knockdown of autophagy molecules ATG7 or Beclin1 enhanced macrophage-mediated phagocytosis and intracellular killing of PA. Additionally, confocal microscopy data showed that induction of autophagy reduced the number of phagosomes and phagolysosomes in macrophages after stimulation with zymosan bioparticles. Conclusions Our study suggested that PA promotes autophagy to suppress macrophage-mediated bacterial phagocytosis and intracellular killing. These insights demonstrated a novel immune evasion mechanism employed by PA, which may provide potential therapeutic strategies of PA infectious diseases.
AB - Objectives To explore the role of autophagy on macrophage-mediated phagocytosis and intracellular killing of Pseudomonas aeruginosa (PA), a common extracellular bacterium which often causes various opportunistic infections. Methods Macrophages were infected with PA or stimulated with zymosan bioparticles. Autophagy was tested by fluorescent microscopy and Western blot for LC3. Phagocytosis and killing efficiency were assessed by plate count assay, flow cytometry or immunofluorescent staining. Phagocytic receptor expression, ROS generation and NO production were examined by PCR, flow cytometry and Griess reaction, respectively. Results PA infection induced autophagy activation in both mouse and human macrophages. Induction of autophagy by rapamycin or starvation significantly inhibited PA internalization by downregulating phagocytosis receptor expression, and suppressed intracellular killing of PA via reducing ROS and NO production in macrophages. While knockdown of autophagy molecules ATG7 or Beclin1 enhanced macrophage-mediated phagocytosis and intracellular killing of PA. Additionally, confocal microscopy data showed that induction of autophagy reduced the number of phagosomes and phagolysosomes in macrophages after stimulation with zymosan bioparticles. Conclusions Our study suggested that PA promotes autophagy to suppress macrophage-mediated bacterial phagocytosis and intracellular killing. These insights demonstrated a novel immune evasion mechanism employed by PA, which may provide potential therapeutic strategies of PA infectious diseases.
KW - Autophagy
KW - Bacterial killing
KW - Macrophages
KW - Phagocytosis
KW - Pseudomonas aeruginosa
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U2 - 10.1016/j.intimp.2016.04.044
DO - 10.1016/j.intimp.2016.04.044
M3 - Article
C2 - 27295610
AN - SCOPUS:84973926856
SN - 1567-5769
VL - 38
SP - 214
EP - 222
JO - International Immunopharmacology
JF - International Immunopharmacology
ER -