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Morita N, Yamazaki T, Murakami Y, Fukui R, Yamai I, Ichimonji I, Nakashima A, Nagaoka F, Takagi H, Miyake K, Akashi-Takamura S. C4b-binding protein negatively regulates TLR4/MD-2 response but not TLR3 response. FEBS Lett 2017; 591:1732-1741. [DOI: 10.1002/1873-3468.12693] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 04/17/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Naoko Morita
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Tatsuya Yamazaki
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Yusuke Murakami
- Division of Innate Immunity; Department of Microbiology and Immunology; Institute of Medical Science; University of Tokyo; Japan
| | - Ryutaro Fukui
- Division of Innate Immunity; Department of Microbiology and Immunology; Institute of Medical Science; University of Tokyo; Japan
| | - Ikuko Yamai
- Division of Innate Immunity; Department of Microbiology and Immunology; Institute of Medical Science; University of Tokyo; Japan
| | - Isao Ichimonji
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Akina Nakashima
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Fumiaki Nagaoka
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Hidekazu Takagi
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
| | - Kensuke Miyake
- Division of Innate Immunity; Department of Microbiology and Immunology; Institute of Medical Science; University of Tokyo; Japan
| | - Sachiko Akashi-Takamura
- Department of Microbiology and Immunology; Aichi Medical University School of Medicine; Japan
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Morita N, Yamai I, Takahashi K, Kusumoto Y, Shibata T, Kobayashi T, Nonaka MI, Ichimonji I, Takagi H, Miyake K, Takamura SA. C4b binding protein negatively regulates TLR1/2 response. Innate Immun 2016; 23:11-19. [PMID: 27794068 DOI: 10.1177/1753425916672312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
TLR2 associates with TLR1 and recognizes microbial lipoproteins. Pam3CSK4, a triacylated lipoprotein, is anchored to the extracellular domain of TLR1 and TLR2 and induces pro-inflammatory signals. Here we show that C4b binding protein (C4BP), which is a complement pathway inhibitor, is a TLR2-associated molecule. Immunoprecipitation assay using anti-TLR2 mAb shows that C4BP binds to TLR2. In C4BP-deficient mice, Pam3CSK4-induced IL-6 levels were increased compared with wild type mice. In C4BP-expressing cells, Pam3CSK4-induced IL-8 production was reduced depending on the C4BP expression levels. These results reveal the important role of C4BP in negative regulation of TLR1/2-dependent pro-inflammatory cytokine production. Furthermore, using a fluorescent conjugated Pam3CSK4, we show that C4BP blocks the binding of Pam3CSK4 to TLR1/2. Finally, we show that exogenous C4BP also inhibits Pam3CSK4-induced signaling leading to IL-8 production. Our results indicate C4BP binding to TLR2 and consequent neutralization of its activity otherwise inducing pro-inflammatory cytokine production. C4BP is a negative regulator of TLR1/2 activity.
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Affiliation(s)
- Naoko Morita
- 1 Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Ikuko Yamai
- 2 Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Koichiro Takahashi
- 3 Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan
| | - Yutaka Kusumoto
- 2 Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Takuma Shibata
- 2 Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Toshihiko Kobayashi
- 2 Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.,4 Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Mayumi I Nonaka
- 5 Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Isao Ichimonji
- 1 Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Hidekazu Takagi
- 1 Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Kensuke Miyake
- 2 Division of Innate Immunity, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Sachiko A Takamura
- 1 Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
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Vairappan B. Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress. World J Hepatol 2015; 7:443-459. [PMID: 25848469 PMCID: PMC4381168 DOI: 10.4254/wjh.v7.i3.443] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/08/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023] Open
Abstract
This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.
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