Gastroenterology

Gastroenterology

Volume 142, Issue 2, February 2012, Pages 366-376
Gastroenterology

Original Research
Basic and Translational—Liver
CCR9+ Macrophages Are Required for Acute Liver Inflammation in Mouse Models of Hepatitis

https://doi.org/10.1053/j.gastro.2011.10.039Get rights and content

Background & Aims

Antigen-presenting cells (APCs) are involved in the induction of liver inflammation. We investigated the roles of specific APCs in the pathogenesis of acute liver injury in mice.

Methods

We used concanavalin A (con A) or carbon tetrachloride to induce acute liver inflammation in mice and studied the roles of macrophages that express CCR9.

Results

After injection of con A, we detected CCR9+CD11b+CD11c macrophages that express tumor necrosis factor (TNF)-α in livers of mice, whereas CCR9+Siglec–H+CD11bCD11clow plasmacytoid DCs (pDCs), which are abundant in normal livers, disappeared. The CCR9+ macrophages were also detected in the livers of RAG-2−/− mice, which lack lymphocytes and natural killer T cells, after injection of con A. Under inflammatory conditions, CCR9+ macrophages induced naive CD4+ T cells to become interferon gamma–producing Th1 cells in vivo and in vitro. CCR9−/− mice injected with con A did not develop hepatitis unless they also received CCR9+ macrophages from mice that received con A; more CCR9+ macrophages accumulated in their inflamed livers than CCR9+ pDCs, CCR9 pDCs, or CCR9 macrophages isolated from mice that had received injections of con A. Levels of CCL25 messenger RNA increased in livers after injection of con A; neutralizing antibodies against CCL25 reduced the induction of hepatitis by con A by blocking the migration of CCR9+ macrophages and their production of TNF-α. Peripheral blood samples from patients with acute hepatitis had greater numbers of TNF-α–producing CCR9+CD14+CD16high monocytes than controls.

Conclusions

CCR9+ macrophages contribute to the induction of acute liver inflammation in mouse models of hepatitis.

Section snippets

Experimental Protocols of con A–Induced Hepatitis

Con A (type IV) was purchased from Sigma-Aldrich (St Louis, MO). Intravenous injections of con A (20 mg/kg) were administered into the tail vein of mice 12 hours before examination under anesthesia. In experiment 1, age-matched wild-type (WT), CCR9−/−, CCR7−/−, and MCP-1−/− mice were treated with con A. In experiment 2, CCR9+ and CCR9 macrophages as well as CCR9+ and CCR9 pDCs were isolated from the liver of con A–treated Ly5.1+ mice. These cells were then adoptively transferred to CCR9−/−

Abundant CCR9+CD11bCD11clow pDCs in the Normal Liver

To clarify the mechanism by which liver inflammation is induced, we focused on liver APCs.1, 2, 15, 16 To segmentalize the APC compartments, we stained liver and spleen mononuclear cells obtained from WT mice with mAb against CD11b and CD11c. As shown in Figure 1A, 3 APC compartments were found in the liver and spleen: cDCs, CD11b+CD11c+; pDCs, CD11bCD11clow; and macrophages, CD11b+CD11c. As previously reported,1 pDCs are more abundant in the liver than in the spleen, although the ratios of

Discussion

We here identify CCR9+ macrophages as key inflammatory cells of con A–induced AH in mice. Figure 7F gives a schematic view of the current study. Our results clearly show that CCR9+ macrophages played a key role in promoting proliferation of CD4+ T cells and generation of IFN-γ–producing Th1 cells as well as NKT cell activation in con A–induced T-cell hepatitis.

To investigate the mechanism of the breakdown of liver tolerance in the inflammatory state, we initially focused on resident

Acknowledgments

H.E. and T.K. contributed equally to this work.

The authors thank K. Tsuchimoto (Kitasato Institute Hospital), R. Umeda, and S. Usui (Keio University) for providing human materials and for critical comments, as well as K. Toda (Kitasato Institute Hospital) for technical assistance.

References (30)

  • A.W. Thomson et al.

    Antigen-presenting cell function in the tolerogenic liver environment

    Nat Rev Immunol

    (2010)
  • P. Ichai et al.

    Etiology and prognosis of fulminant hepatitis in adults

    Liver Transpl

    (2008)
  • H. Sahin et al.

    Functional role of chemokines in liver disease models

    Nat Rev Gastroenterol Hepatol

    (2010)
  • C. Koenecke et al.

    CCR9 and inflammatory bowel disease

    Expert Opin Ther Targets

    (2009)
  • M. Saruta et al.

    Phenotype and effector function of CC chemokine receptor 9-expressing lymphocytes in small intestinal Crohn's disease

    J Immunol

    (2007)
  • Cited by (0)

    Conflicts of interest The authors disclose no conflicts.

    Funding Supported part by grants-in-aid for Scientific Research, Scientific Research on Priority Areas, Exploratory Research and Creative Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology; the Japanese Ministry of Health, Labour and Welfare; the Japan Medical Association; Foundation for Advancement of International Science; and Keio University Medical Fund.

    Writing assistance was provided by Dr Peter Hawkes (Kansai Language College) and Edanz Group Ltd and funded by grants-in-aid for Scientific Research, Scientific Research on Priority Areas, Exploratory Research.

    View full text