Proinflammatory cytokines TNF-α and IFN-γ alter laminin expression under an apoptosis-independent mechanism in human intestinal epithelial cells

Abstract

Laminins are basement membrane molecules that mediate cell functions such as adhesion, proliferation, migration, and differentiation. In the normal small intestine, laminin-5 and -10 are mainly expressed at the base of villus cells. However, in Crohn's disease (CD), a major redistribution of these laminins to the crypt region of the inflamed ileal mucosa has been observed, suggesting a possible relationship between laminin expression and cytokine and/or growth factor production, which is also altered in CD. The aim of this study was to test the hypothesis that proinflammatory cytokines can modulate laminin expression by intestinal epithelial cells. The effect of TNF-α, IFN-γ, IL-1β, IL-6, and transforming growth factor (TGF)-β was analyzed on the expression of laminins in the normal human intestinal epithelial crypt (HIEC) cell line. When treated with a single cytokine, HIEC cells secreted small amounts of laminin-5 and -10. Only TNF-α and TGF-β induced a slight increase in the secretion of these laminins. However, in combination, TNF-α and IFN-γ synergistically stimulated the secretion of both laminin-5 and -10 in HIEC cells. Transcript analyses suggested that the upregulation of the two laminins might depend on distinct mechanisms. Interestingly, the TNF-α and IFN-γ combination was also found to significantly promote apoptosis. However, the effect of cytokines on the secretion of laminins was maintained even after completely blocking apoptosis by inhibiting caspase activities. These results demonstrate that laminin production is specifically modulated by the proinflammatory cytokines TNF-α and IFN-γ in intestinal epithelial cells under an apoptosis-independent mechanism.

Proinflammatory cytokines tumor necrosis factor-α and interferon-γ alter tight junction structure and function in the rat parotid gland Par-C10 cell line

“…1B). These results suggest that prolonged exposure of salivary gland epithelium to cytokines can affect TJ permeability properties, similar to intestinal (1,8,14,18,35,38,59,77) and airway epithelia (12).…”

“…Inflammatory cytokines in SS are synthesized and released by lymphocytes (16,29) and salivary gland epithelium (68,76). Cytokines have been shown to alter intestinal and airway epithelial TJ structure and function (1,8,12,14,18,35,38,54,59,77). Moreover, alterations in TJ structure have been associated with other inflammatory autoimmune diseases, such as Crohn's disease (31), celiac sprue (65), and cystic fibrosis (12).…”

“…Previous studies showed that proinflammatory cytokines such as TNF-␣ and IFN-␥ decrease transepithelial electrical resistance (TER) and increase paracellular permeability to ions and normally impermeant molecules in intestinal (1,8,14,18,35,38,59,77) and airway epithelia (12). Decreases in the integrity of intercellular tight junctions (TJs) of intestinal epithelium have been associated with Crohn's disease (31,67) and celiac sprue (65), and cystic fibrosis in airway epithelium (12).…”

Intestinal Inflammation Increases the Expression of the P2Y6 Receptor on Epithelial Cells and the Release of CXC Chemokine Ligand 8 by UDP

“…Specific kinase inhibitors or P2Y receptor antagonists were added 30 min to serum-free medium before nucleotide stimulation. Inflammatory-like stress was induced in Caco-2/15 cells by adding a combination of 10 ng/ml TNF-␣ and 10 ng/ml IFN-␥ for 6 h at 37°C, as previously described (27).…”

“…2I) and 4-day postconfluent Caco-2/15 cells (Fig. 2J) by challenging the cells with a combination of TNF-␣ (10 ng/ml) and IFN-␥ (10 ng/ml) (27). Immunoblotting for P2Y 6 receptor expression using a commercially available Ab against the P2Y 6 receptor revealed three bands at ϳ36, 40, and 55 kDa for IEC-6, and 34, 40, and 55 kDa for Caco-2/15 cells (Fig.…”