scholarly journals Effect of (−)-Epigallocatechin Gallate on Activation of JAK/STAT Signaling Pathway by Staphylococcal Enterotoxin A

Toxins ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 609
Author(s):  
Yuko Shimamura ◽  
Rina Noaki ◽  
Ami Kurokawa ◽  
Mio Utsumi ◽  
Chikako Hirai ◽  
...  

Staphylococcal enterotoxin A (SEA), which is a superantigen toxin protein, binds to cytokine receptor gp130. Gp130 activates intracellular signaling pathways, including the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway. The effects of SEA on the JAK/STAT signaling pathway in mouse spleen cells were examined. After treatment with SEA, mRNA expression levels of interferon gamma (IFN-γ) and suppressor of cytokine-signaling 1 (SOCS1) increased. SEA-induced IFN-γ and SOCS1 expression were decreased by treatment with (−)-epigallocatechin gallate (EGCG). The phosphorylated STAT3, Tyr705, increased significantly in a SEA concentration-dependent manner in mouse spleen cells. Although (−)-3″-Me-EGCG did not inhibit SEA-induced phosphorylated STAT3, EGCG and (−)-4″-Me-EGCG significantly inhibited SEA-induced phosphorylated STAT3. It was thought that the hydroxyl group at position 3 of the galloyl group in the EGCG was responsible for binding to SEA and suppressing SEA-induced phosphorylation of STAT3. Through protein thermal shift assay in vitro, the binding of the gp130 receptor to SEA and the phosphorylation of STAT3 were inhibited by the interaction between EGCG and SEA. As far as we know, this is the first report to document that EGCG inhibits the binding of the gp130 receptor to SEA and the associated phosphorylation of STAT3.

1991 ◽  
Vol 37 (8) ◽  
pp. 586-589
Author(s):  
Kunihiro Shinagawa ◽  
Katsuhiko Omoe ◽  
Naonori Matsusaka ◽  
Shunji Sugii

Eight murine monoclonal antibodies (MAbs) against staphylococcal enterotoxin D (SED) were obtained by fusion of myeloma cells with mouse spleen cells immunized with SED only or a combination of SED and either enterotoxin A (SEA) or enterotoxin E (SEE). When only SED was used as an immunogen, six MAbs were specific for SED only, whereas one MAb was reactive with both SED and SEE when both SEs were used as immunogens. One MAb reacted with SEA, SED, and SEE when both SEA and SED were used as immunogens. A MAb with the highest reactivity to SED was used to prepare an immunosorbent for purification of SED by immunoaffinity chromatography. Approximately 70% of the partially purified SED was recovered in the eluate. The purified SED was electrophoretically and antigenically pure. Immunoaffinity chromatography proved useful in the purification of SED in terms of ease of purification, percent enterotoxin, and enterotoxin purity. Key words: enterotoxin D, monoclonal antibodies, Staphylococcus aureus.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1867
Author(s):  
Yuko Shimamura ◽  
Mio Utsumi ◽  
Chikako Hirai ◽  
Ami Kurokawa ◽  
Toshiyuki Kan ◽  
...  

Staphylococcal enterotoxin A (SEA) functions both as superantigens that stimulate non-specific T cell proliferation as well as potent gastrointestinal toxins. We previously reported that (−)-epigallocatechin gallate (EGCG) binds to SEA. Therefore, the ability of EGCG to inhibit SEA toxin activity was examined. As a result, EGCG significantly decreased SEA-induced expression and production of interferon gamma (IFN-γ). In addition, EGCG inhibited SEA-induced spleen cell proliferation. To investigate the role of the galloyl group in EGCG on SEA cytotoxicity in more detail, the effect of the binding of a hydroxyl group at position 3 of the galloyl group in EGCG to SEA on SEA cytotoxicity was examined using two methylated EGCG. SEA cytotoxicity was significantly controlled in both (−)-3′′-Me-EGCG and (−)-4′′-Me-EGCG. These results suggest that EGCG inhibits toxic activity via direct interaction with SEA or without any interaction with SEA. The binding affinity between SEA and EGCG under in vivo conditions was examined using a model solution. Although after treatment under acidic and alkaline conditions, the presence of protein and the digestive tract model solution, EGCG still interacted with SEA. Our studies are the first to demonstrate the effect of the binding of EGCG to SEA on toxin activity.


FEBS Letters ◽  
2005 ◽  
Vol 579 (5) ◽  
pp. 1101-1108 ◽  
Author(s):  
Zhike Zi ◽  
Kwang-Hyun Cho ◽  
Myong-Hee Sung ◽  
Xuefeng Xia ◽  
Jiashun Zheng ◽  
...  

2009 ◽  
Vol 203 (2) ◽  
pp. 417-428 ◽  
Author(s):  
Xin-rui Hao ◽  
Dong-li Cao ◽  
Yan-wei Hu ◽  
Xiao-xu Li ◽  
Xie-hong Liu ◽  
...  

1986 ◽  
Vol 40 ◽  
pp. 154
Author(s):  
Takehiko Watanabe ◽  
Kumiko Kawaguchi-Nagata ◽  
Yukihiko Kitamura ◽  
Atsushi Yamatodani ◽  
Hiroshi Wada ◽  
...  

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4975-4975
Author(s):  
Ruiqing Zhou ◽  
Huiqing He ◽  
Ziwen Guo ◽  
Dafa Qiu ◽  
Weihua Li ◽  
...  

Abstract Background: T-cell activation plays a critical role in the pathogenesis of acute graft-versus-host disease (GVHD). Quiescent T cells utilize oxidative phosphorylation to generate ATP, whereas activated T cells utilize glycolysis, so use glycolysis inhibitor may be a metabolically regulator needed to control T cells induced GVHD. The mixed lymphocytes culture (MLC) was used as a model to evaluate the effect of treatment for GVHD in vitro. Glucolysis inhibitor 3-Bromopyruvic acid (3-BrPA), a glucolysis inhibitor, can effectively induce multidrug resistance leukemia cell lines apoptosis and enhanced chemotherapy-induced cytotoxity to leukemia cells. Objective : This study aimed to study the effects of glycolytic inhibitor 3-Bromopyruvate (3-BrPA) on the proliferation, the apoptosis, the T lymphocyte subsets and the contents of cytokine IL-4 and IFN-γ in mouse spleen cells harvested from mixed lymphocyte culture. Methods An one-way mixed lymphocyte culture system characterized by labeled responder cells with BALB/c mouse spleen cells (H-2kd) and stimulator cells with C57BL/6 mouse spleen cells (H-2kb) was established. With treatment of 3-BrPA at different concentrations (0-200 μmol/L), the CCK-8 method was applied for lymphoproliferation activity, flow cytometry for cell surface markers of CD3, CD4 and CD8, and ELISA method for the levels of cytokine IL-4 and IFN-γ in the supernatant. Results: The CCK-8 test revealed that 3-BrPA in middle or high concentrations (over IC 30, 20 μmol/L) displayed a dose-dependent inhibitory effect on T-cell proliferation of MLC system. The IC50 were 48.6、41.2 and 41.9 μmol/L after 24 h, 36 h and 48 h of culture, respectively. FCM test discovered that the inhibitory effect mainly occurred in the CD4+ cells. After 48 h of culture, the apoptosis rate of 0, 10, 20, 50 and 100 μmol/L group were 4.86±0.88%, 5.2±1.13%, 12.63±2.97%, 18.55±4.06% and 22.47±3.61%, respectively. With treatment of 20 or 50μmol/L 3-BrPA, the levels of IFN-γ decreased obviously to 243.37±15.64 ng/L and 164.25±20.14 ng/L, compared with the control group (277.61±18.46 ng/L). The levels of IL-4 increased mildly to 33.18±5.69 ng/L and 31.06±6.06 ng/L, compared with the control group (28.64±3.97ng/L). Thus, the IFN-γ/IL-4 ratio decreased significantly. Conclusions :The results indicated that 3-BrPA could inhibit T cells proliferation, induce apoptosis and contribute to the Th2 cytokine environment in murine mixed lymphocyte culture system. Disclosures Liu: National Natural Science Foundation of China (81270647, 81300445, 81200388): Research Funding; National High Technology Research and Development Program of China (863 Program) (2011AA020105): Research Funding; National Public Health Grand Research Foundation (201202017): Research Funding; Natural Science Foundation of Guangdong Province (S2012010009299): Research Funding; the project of health collaborative innovation of Guangzhou city (201400000003-4, 201400000003-1): Research Funding; the Technology Plan of Guangdong Province of China (2012B031800403): Research Funding; the project of the Zhujiang Science & Technology Star of Guangzhou city (2013027): Research Funding.


Sign in / Sign up

Export Citation Format

Share Document