Proinflammatory cytokine synthesis by mucosal fibroblasts from mouse colitis is enhanced by interferon-γ-mediated up-regulation of CD40 signalling

Abstract

SummaryGut mesenchymal fibroblasts form complex phenotypical and functional populations. They participate actively in homeostatic maintenance of the extracellular matrix, epithelial barrier function, repair mechanisms and leucocyte migration. In inflammation, they become activated, change matrix expression and synthesize proinflammatory mediators. Subpopulations of mucosal fibroblasts express CD40 and the aim of this study was to define its role in their proinflammatory function. Stable primary fibroblast lines derived from normal mouse colon and inflamed colon from CD4 + CD45RB high -transplanted SCID mice were used as models to explore the role of mucosal fibroblast CD40 in the inflammatory process. Phenotype correlated with in situ fibroblast phenotype in the tissues of origin. Lines from both sources co-expressed CD40 and Thy1·2 independently of a-smooth muscle actin. A subpopulation of CD40 + fibroblasts from normal colon expressed CD40 at high levels and expression was enhanced by interferon (IFN)-g treatment, whereas all CD40 + fibroblasts from colitis expressed at low levels and expression was unaffected by IFN-g treatment. Despite lower-level expression of CD40 by cells from colitis, they secreted constitutively interleukin (IL)-6 and C-C chemokine (CCL)2. Ligation of CD40 enhanced secretion of these mediators and induced secretion of CCL3. CD40 in cells from colitis was more responsive to ligation than CD40 on cells from normal tissue and this sensitivity was amplified selectively by the action of IFN-g. We conclude that the inflammatory milieu in colitis induces long-lasting changes in phenotype and proinflammatory function in colonic fibroblasts. In particular, proinflammatory signalling from fibroblast CD40 is amplified synergistically by the Th1 effector T cell cytokine, IFN-g.

Profibrotic Phenotype of Conjunctival Fibroblasts from Mucous Membrane Pemphigoid

“…Apart from selective amplification of subpopulations of activated phenotype fibroblasts derived from various sources, induction of the profibrotic fibroblast phenotype is also thought to be influenced by profibrotic mediators in the inflammatory milieu, 30,42 and sometimes cell-cell contact between immune cells and fibroblasts. 15 The phenotypic changes have been shown, in pulmonary fibrosis fibroblasts, to reflect genome-wide derangements of the gene expression pathway.…”

Stromal fibroblasts derived from mammary gland of bovine with mastitis display inflammation-specific changes

“…With the stimulation of cytokines, which are primarily produced by monocytes/macrophages early in the inflammatory reaction, fibroblasts can synthesize and express an upregulated effector phenotype for some cytokines; these fibroblast-derived cytokines may play a significant role in the amplification of the inflammatory response 11 . The roles of fibroblasts in the regulation of immune responses have been clarified in the inflammatory reactions of colitis 12 , airway inflammation 13 , and tumor-enhancing inflammation of the mammary gland 14 .…”

Influence of experimentally induced Eimeria tenella infection on gene expression of some host response factors in chickens

“…According to other investigations, IL-8 is expressed by various cells, such as epithelial and endothelial cells, and fibroblasts. By secretion of cytokines and chemokines these cells prolong the survival of Th1 lymphocytes (Karlson et al, 2007).…”