Isoliquiritigenin suppresses human T Lymphocyte activation via covalently binding cysteine 46 of IκB kinase.
The efficacious practice of precision personalized medicine requires a more exact understanding of the molecular mechanisms of drug, hence then it is necessary to identify the binding site of the drugs derived from natural sources. In the study, we investigated the suppressive effect and underlying mechanism of isoliquiritigenin (2',4',4-trihydroxychalcone; ILG), a phyto-flavonoid, on human T lymphocyte activation in vitro and in vivo. The results showed that ILG dose-dependently suppressed human T cell activation via suppressing IκBα phosphorylation and degradation, NF-κB nuclear translocation and IKKβ activity. Molecular docking results predicted that cysteine 46 (Cys-46) is probably the binding site of ILG on IKKβ, and this prediction has been validated by competition assay and kinase assay. To further verify the binding site of this compound in vivo, IKKβC46A transgenic (IKKβC46A) mice were generated. We found that ILG had a less potent immune-suppressive effect in homozygous IKKβC46A mice than IKKβ wild type (IKKβ wt) littermates with the delay-type hypersensitivity (DTH), suggesting that ILG cannot significantly suppress the inflammation due to the mutation of Cys-46 in the transgenic mice. Collectively, our findings indicate that the ILG inhibited T cell activation in vivo and in vitro via directly binding to IKKβ Cys46.
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Fenggen
F
Yan
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Fen
F
Yang
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Rui
R
Wang
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Xiao Jun
XJ
Yao
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Liping
L
Bai
Guangdong Provincial Academy of Chinese Medical Sciences, Guangzhou, China.
Xing
X
Zeng
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
JiaJun
J
Huang
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Vincent Kam Wai
VKW
Wong
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Christopher Wai Kei
CWK
Lam
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Hua
H
Zhou
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Xiaohui
X
Su
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Juan
J
Liu
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Ting
T
Li
State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Macau, China.
Liang
L
Liu
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D047188:Chalcones / Q000008:administration & dosage* / Q000494:pharmacology; D003545:Cysteine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D059748:Proteolysis; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects*
D047188:Chalcones; D004791:Enzyme Inhibitors; C040920:isoliquiritigenin; D051550:I-kappa B Kinase; D003545:Cysteine
IKKβ; T lymphocyte; cysteine 46; immune-suppression; isoliquiritigenin