Int J Biol Sci 2007; 3(7):477-485. doi:10.7150/ijbs.3.477
Smad3 -signalling and Th2 cytokines in normal mouse airways and in a mouse model of asthma
1. Unit of Excellence for Immunotoxicology, Finnish Institute of Occupational Health, Helsinki, Finland
This study investigates the role of Smad3 signalling for the T-helper2 (Th2) cytokine homeostasis in normal lungs and in a mouse model of asthma.
We used mice deficient for Smad3, a central part of the major signal transduction pathway for TGF-β and other related cytokines, and a mouse model for allergic asthma with ovalbumin (OVA) as the antigen.
Compared to wild type mice, naive (unmanipulated) Smad3-/- mice exhibited significantly increased levels of proinflammatory cytokines and IL-4 as well as the Th2 associated transcription factor GATA-3 in the lung tissue and bronchoalveolar lavage (BAL). In the asthma model, mucin secretion and airway hyperresponsiveness (AHR) after allergen exposure was significantly increased in the Smad3-/- mice as compared to wild type (WT) mice. IL-4 levels in Smad3-/- were similar to those encountered in WT mice but IL-13 levels were decreased in the airways of OVA sensitized Smad3-/- mice compared to corresponding WT mice.
The results indicate that a lack of Smad3 dependent signalling in the normal state will lead to an increase in the GATA-3 levels and as a result of this the levels of IL-4 increase. However, the lack of Smad3 also seems to inhibit expression of some cytokines, especially IL-13. Our results also indicate that in the inflammatory state TGF-β or related cytokines functions to counterbalance the effects of IL-4 rather than to critically regulate its expression.
Keywords: Smad3, TGF-β, Asthma.
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How to cite this article:
Anthoni M, Wang G, Leino MS, Lauerma AI, Alenius HT, Wolff HJ. Smad3 -signalling and Th2 cytokines in normal mouse airways and in a mouse model of asthma. Int J Biol Sci 2007; 3(7):477-485. doi:10.7150/ijbs.3.477. Available from http://www.ijbs.com/v03p0477.htm