SELECTED ARTICLES FROM THE RECENT LITERATURE 2008

9/22/2008

The relationship between mast cells and smooth muscle phenotype in the airway

Summary
The authors of this paper, from the United Kingdom, have published extensively the phenomenon of mast cell invasion of smooth muscle in asthma. One of the most important characteristics distinguishing asthma from eosinophilic bronchitis is the presence of mast cell infiltration of smooth muscle in the airway. They have postulated therefore that such invasion represents a significant "player" in the pathogenesis of asthma. They investigate this hypothesis further in this article.

They found that in vitro coculture of human airway smooth muscle with beta tryptase or mast cells (with and without IgE/anti-IgE activation), increases the production of smooth muscle derived TGF-beta. It also enhances smooth muscle alpha actin expression and the response to agonist-provoked smooth muscle contraction.

This effect was inhibited by a serine protease inhibitor (leupeptin) as well as neutralization of TGF-beta. In addition, they found that bronchial smooth muscle biopsies obtained from asthmatics demonstrate a strong correlation between the intensity of alpha actin in smooth muscle and the number of mast cells within or adjacent to the smooth muscle bundle.

They thus concluded that mast cells, via tryptase release, enhance smooth muscle production of TGF-beta and promote smooth muscle differentiation into a more contractile phenotype.

Reference
Woodman L, et al. Mast cells promote airway smooth muscle cell differentiation via autocrine up-regulation of TGF-beta 1. Journal of Immunology 2008; 181:5001-5007.

 

<-- BACK