Intracolonic infusion of fecal supernatants from ulcerative colitis patients triggers altered permeability and inflammation in mice: Role of cathepsin G and protease-activated receptor-4
✍ Scribed by Marta Dabek; Laurent Ferrier; Anita Annahazi; Valérie Bézirard; Arnaud Polizzi; Christel Cartier; Mathilde Leveque; R. Roka; Tibor Wittmann; Vassilia Theodorou; Lionel Bueno
- Book ID
- 102861561
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 579 KB
- Volume
- 17
- Category
- Article
- ISSN
- 1078-0998
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✦ Synopsis
Background:
Cathepsin g (cat-g) is a neutrophil serine-protease found in the colonic lumen of ulcerative colitis (uc) patients. cat-g is able to activate protease-activated receptor-4 (par(4) ) located at the apical side of enterocytes, leading to epithelial barrier disruption. however, the mechanisms through which cat-g triggers inflammation are not fully elucidated. the aims of our study were to evaluate in vivo the effects of uc fecal supernatants and cat-g on epithelial barrier function and inflammation, and the connection between these two parameters.
Methods:
Male balb/c mice were used in this study. we evaluated the effect of a 2-hour intracolonic infusion of 1) fecal supernatants from uc patients pretreated or not with specific cat-g inhibitor (scgi); 2) par(4) -activating peptide (par(4) -ap); and 3) cat-g on colonic myeloperoxidase (mpo) activity and paracellular permeability (cpp). the involvement of par(4) was assessed by pretreating animals with pepducin p4pal-10, which blocks par(4) signaling. we investigated the role of myosin light chain (mlc) kinase by using its inhibitor, ml-7, and we determined phosphorylated mlc (pmlc) levels in mice colonic mucosa.
Results:
Uc fecal supernatants, cat-g, and par(4) agonist increased both cpp and mpo activity in comparison with healthy subjects fecal supernatants. ml-7 inhibited the cpp increase triggered by cat-g by 92.3%, and the enhanced mpo activity by 43.8%. intracolonic infusion of uc fecal supernatant determined an increased phosphorylation level of mlc.
Conclusions:
These observations support that luminal factors such as cat-g play an important proinflammatory role in the pathogenesis of colitis, mainly depending on cpp increase by mlc phosphorylation.