Transforming growth factor-β signalling and matrix metalloproteinases in the mucosa overlying Crohn's disease strictures

Di Sabatino, A., Jackson, Claire, Pickard, Karen M, Buckley, M., Rovedatti, L., Leakey, N. A. B., Picariello, L., Cazzola, P., Monteleone, G., Tonelli, Francesco, Corazza, G.R., MacDonald, T.T. and Pender, S.L.F. (2009) Transforming growth factor-β signalling and matrix metalloproteinases in the mucosa overlying Crohn's disease strictures. Gut, 58 (6), 777-789. (doi:10.1136/gut.2008.149096).

Abstract

Background and Aims: In addition to its crucial role in dampening tissue-damaging immune responses in the gut, transforming growth factor β (TGFβ) is a potent profibrogenic agent inducing collagen synthesis and regulating the balance between matrix-degrading matrix metalloproteinases (MMPs) and their inhibitors (TIMPs). TGFβ signalling was investigated by analysis of Smad proteins and MMPs/TIMPs in the mucosa overlying strictures in patients with Crohn’s disease (CD).

Methods: Specimens were collected from macroscopically normal mucosa overlying strictured and non-strictured gut of patients with fibrostenosing CD. Isolated myofibroblasts were cultured with anti-TGFβ blocking antibody or TGFβ1. TGFβ transcripts were analysed by quantitative reverse transcription-PCR (RT-PCR). Smad proteins and MMPs were determined by immunoblotting. MMP-12 activity was measured by a real-time MMP-12 activity assay. An in vitro wound-healing scratch assay was used to assess myofibroblast migration.

Results: TGFβ transcripts, phosphorylated Smad2–Smad3 (pSmad2–3) and TIMP-1 proteins were higher in mucosa overlying strictures than in mucosa overlying non-strictured areas. In contrast, mucosa overlying strictured gut had lower expression of Smad7, MMP-12 and MMP-3. Myofibroblasts from mucosa overlying strictured gut showed higher TGFβ transcripts, a greater pSmad2–3 response to TGFβ, increased TIMP-1, lower Smad7, increased collagen production and reduced migration ability compared with myofibroblasts from mucosa overlying non-strictured gut. TGFβ blockade increased myofibroblast MMP-12 production and migration, more obviously in myofibroblasts isolated from mucosa overlying non-strictured compared with strictured gut.

Conclusions: Changes in TGF-β signalling and MMP production were identified in the mucosa overlying strictures in CD which may give a window into the process of fibrosis.

This record has no associated files available for download.

Contributors

Author: Claire Jackson

Download statistics