Volume 159, Issue 3 pp. 546-554
Open Access

Transforming growth factor-β/Smad3 signalling regulates inflammatory responses in a murine model of contact hypersensitivity

M. Anthoni

M. Anthoni

Unit of Excellence in Immunotoxicology

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N. Fyhrquist-Vanni

N. Fyhrquist-Vanni

Unit of Excellence in Immunotoxicology

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H. Wolff

H. Wolff

Team for Biological Mechanisms and Prevention of Work-Related Diseases

Department of Pathology, Helsinki University Central Hospital, Helsinki, Finland

Department of Pathology, Kymenlaakso Central Hospital, Kotka, Finland

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H. Alenius

H. Alenius

Unit of Excellence in Immunotoxicology

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A. Lauerma

A. Lauerma

Control of Hypersensitivity Diseases, Finnish Institute of Occupational Health, FIN-00250 Helsinki, Finland

Department of Dermatology, Venereology and Allergology, University of Helsinki, Helsinki, Finland

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First published: 21 August 2008
Citations: 15
Antti Lauerma.
E-mail: [email protected]

Conflicts of interest
None declared.

M.A. and N.F.-V. contributed equally to this study.

Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2·5, which does not permit commercial exploitation.

Summary

Background Transforming growth factor (TGF)-β is an important modulator of immune functions and cellular responses, such as differentiation, proliferation, migration and apoptosis. The Smad proteins, which are intracellular TGF-β signal transducers, mediate most actions of TGF-β.

Objectives This study examines the role of Smad3 in a murine model of contact hypersensitivity (CHS).

Methods The CHS response to oxazolone was studied in Smad3-deficient mice. The ear swelling response was measured and skin biopsies from oxazolone-sensitized skin areas were obtained for RNA isolation, immunohistochemical analyses and histology. Ear draining lymph nodes were collected for RNA isolation and proliferation tests. Quantitative real-time polymerase chain reaction was used to quantify mRNA expression of cytokines, chemokines and transcription factors.

Results The expression of proinflammatory [interleukin (IL)-1β, tumour necrosis factor-α, IL-6], Th2 (IL-4) and Th17 type cytokines (IL-17), as well as regulatory components (TGF-β, Foxp3) increased significantly at the mRNA level in the skin of oxazolone-treated Smad3−/− mice when compared with wild-type controls. The expression of the Th1 type cytokine IFN-γ and the chemokines CXCL9 and CXCL10 was, however, unaffected by the lack of Smad3. The number of neutrophils and expression of the chemokines CCL3 and CXCL5, which are both involved in neutrophil recruitment, were increased in mice lacking Smad3. Also Th2 type chemokines CCL24, CCL3 and CXCL5 were increased in the skin of Smad3−/− mice compared with wild-type mice. In the lymph nodes, mRNA of IL-1β and IL-17, but not IL-4, TGF-β or Foxp3, was increased in Smad3−/− mice during the CHS response.

Conclusions The lack of intact TGF-β signalling via Smad3 results in an increased proinflammatory, Th2 and Th17 type response in the skin, as well as increased expression of regulatory elements such as TGF-β and Foxp3. Understanding the role of Smad3 in the CHS response may offer treatment and prevention strategies in this often disabling disease.

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