TY - JOUR
T1 - Epigallocatechin gallate-mediated cell death is triggered by accumulation of reactive oxygen species induced via the Cpx two-component system in Escherichia coli
AU - Nie, Tao
AU - Zhang, Chenlu
AU - Huang, Antian
AU - Li, Ping
N1 - Funding Information:
We thank Professor Chengshu Wang, Professor Chongjun Qin, and Peng Jiang (Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences) for kindly providing guidance on constructing cpxR.This work was supported by the National Key Technology R and D Program of China (No. 2015BAD16B01), the National Natural Science Foundation of China (No. 21476176), the National High Technology Research and Development Program of China (863 Program, No. 2015AA021002), and the International Science and Technology Cooperation Programs of Anhui (No. 1503062006).
Publisher Copyright:
© 2018 Nie, Zhang, Huang and Li.
PY - 2018/2/15
Y1 - 2018/2/15
N2 - The high antimicrobial activity of epigallocatechin gallate (EGCG), the most bioactive component of tea polyphenol with a number of health benefits, is well-known. However, little is known about the mechanism involved. Here, we discovered the relationship between reactive oxygen species (ROS), the Cpx system, and EGCG-mediated cell death. We first found an increase in ampicillin resistance as well as the transcription level of a LD-transpeptidase (LD-TPase) involved in cell wall synthesis; ycbB transcription was upregulated whereas that of another LD-TPase, ynhG, appeared to be constant after a short exposure of Escherichia coli to sub-inhibitory doses of EGCG. Additionally, the transcription level of cpxP, a downstream gene belonging to the Cpx regulon, was positively correlated with the concentration of EGCG, and significant upregulation was detected when cells were treated with high doses of EGCG. Through analysis of a cpxR deletion strain (ΔcpxR), we identified a constant ROS level and a notable increase in the survival rate of ΔcpxR, while the ROS level increased and the survival rate decreased remarkably in the wild-type strain. Furthermore, thiourea, which is an antioxidant, reduced the ROS level and antimicrobial activity of EGCG. Taken together, these results suggest that EGCG induces ROS formation by activating the Cpx system and mediates cell death.
AB - The high antimicrobial activity of epigallocatechin gallate (EGCG), the most bioactive component of tea polyphenol with a number of health benefits, is well-known. However, little is known about the mechanism involved. Here, we discovered the relationship between reactive oxygen species (ROS), the Cpx system, and EGCG-mediated cell death. We first found an increase in ampicillin resistance as well as the transcription level of a LD-transpeptidase (LD-TPase) involved in cell wall synthesis; ycbB transcription was upregulated whereas that of another LD-TPase, ynhG, appeared to be constant after a short exposure of Escherichia coli to sub-inhibitory doses of EGCG. Additionally, the transcription level of cpxP, a downstream gene belonging to the Cpx regulon, was positively correlated with the concentration of EGCG, and significant upregulation was detected when cells were treated with high doses of EGCG. Through analysis of a cpxR deletion strain (ΔcpxR), we identified a constant ROS level and a notable increase in the survival rate of ΔcpxR, while the ROS level increased and the survival rate decreased remarkably in the wild-type strain. Furthermore, thiourea, which is an antioxidant, reduced the ROS level and antimicrobial activity of EGCG. Taken together, these results suggest that EGCG induces ROS formation by activating the Cpx system and mediates cell death.
KW - Antimicrobial
KW - Epigallocatechin gallate
KW - Escherichia coli
KW - Reactive oxygen species
KW - Two-component system
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U2 - 10.3389/fmicb.2018.00246
DO - 10.3389/fmicb.2018.00246
M3 - Article
C2 - 29497416
AN - SCOPUS:85042126722
VL - 9
JO - Frontiers in Microbiology
JF - Frontiers in Microbiology
SN - 1664-302X
IS - FEB
M1 - 246
ER -