Pro-inflammatory cytokines induce c-fos expression followed by IL-6 release in human airway smooth muscle cells

BACKGROUND: Airway smooth muscle (ASM) is considered to be a target for mediators released during airway inflammation. AIMS: To investigate the expression of c-fos, a constituent of the transcription factor activator protein-1, in human ASM cells. In addition, to measure the release of interleukin (IL)-6 into the conditioned medium of stimulated ASM cells, as well as DNA biosynthesis and changes in cell number. METHODS: Serum-deprived human ASM cells in the G0/G1 phase were stimulated with the pro-inflammatory cytokines; tumour necrosis factor-alpha, IL-1beta, IL-5 and IL-6. The expression of mRNA encoding the proto-oncogene c-fos was measured by Northern blot analysis. Cell proliferation was assessed by [3H]-thymidine incorporation assays and cell counting, and IL-6 levels in cell-conditioned medium were measured by enzyme-linked immunosorbent assay. RESULTS: All of the cytokines investigated induced a rapid (within 1 h) and transient increase in the expression of mRNA encoding c-fos, followed by the expression and enhanced release of IL-6. Cell proliferation remained unchanged in cytokine-stimulated cells. CONCLUSIONS: Cytokine-induced c-fos expression in human ASM cells could be described as a marker of cell 'activation'. The possible association of these results with airway inflammation, through secondary intracellular mechanisms such as cytokine production, is discussed

The role of the small intestine in the development of dietary fat-induced obesity and insulin resistance in C57BL/6J mice

<p>Abstract</p> <p>Background</p> <p>Obesity and insulin resistance are two major risk factors underlying the metabolic syndrome. The development of these metabolic disorders is frequently studied, but mainly in liver, skeletal muscle, and adipose tissue. To gain more insight in the role of the small intestine in development of obesity and insulin resistance, dietary fat-induced differential gene expression was determined along the longitudinal axis of small intestines of C57BL/6J mice.</p> <p>Methods</p> <p>Male C57BL/6J mice were fed a low-fat or a high-fat diet that mimicked the fatty acid composition of a Western-style human diet. After 2, 4 and 8 weeks of diet intervention small intestines were isolated and divided in three equal parts. Differential gene expression was determined in mucosal scrapings using Mouse genome 430 2.0 arrays.</p> <p>Results</p> <p>The high-fat diet significantly increased body weight and decreased oral glucose tolerance, indicating insulin resistance. Microarray analysis showed that dietary fat had the most pronounced effect on differential gene expression in the middle part of the small intestine. By overrepresentation analysis we found that the most modulated biological processes on a high-fat diet were related to lipid metabolism, cell cycle and inflammation. Our results further indicated that the nuclear receptors Ppars, Lxrs and Fxr play an important regulatory role in the response of the small intestine to the high-fat diet. Next to these more local dietary fat effects, a secretome analysis revealed differential gene expression of secreted proteins, such as Il18, Fgf15, Mif, Igfbp3 and Angptl4. Finally, we linked the fat-induced molecular changes in the small intestine to development of obesity and insulin resistance.</p> <p>Conclusion</p> <p>During dietary fat-induced development of obesity and insulin resistance, we found substantial changes in gene expression in the small intestine, indicating modulations of biological processes, especially related to lipid metabolism. Moreover, we found differential expression of potential signaling molecules that can provoke systemic effects in peripheral organs by influencing their metabolic homeostasis. Many of these fat-modulated genes could be linked to obesity and/or insulin resistance. Together, our data provided various leads for a causal role of the small intestine in the etiology of obesity and/or insulin resistance.</p

Fish oil supplementation induces anti-atherogenic gene expression profiles in human blood mononuclear cells

Fish oil supplementation is generally seen as beneficial for human health, due to the presence of n-3 polyunsaturated fatty acids (n-3 PUFAs). These fatty acids can elicit their effect through changes in gene expression. Effects of n-3 PUFAs on gene expression of inflammatory and atherogenic markers have been shown in several in vitro and animal studies. However, little evidence is available on human in vivo studies on n-3 PUFA related gene expression. In the present study we investigate the effects of EPA and DHA supplementation for 6 months on gene expression profiles of peripheral blood mononuclear cells (PBMCs). Whole genome microarray analysis was performed on PBMC RNA from subjects who received 1.8 grams of EPA and DHA in capsules (n=23) or capsules containing high oleic acid sunflower oil (HOSF)(n=25). Intake of EPA and DHA resulted in a change of 1040 genes. We found a down-regulation in inflammatory and atherogenic related pathways, such as NF-κB signaling, eicosanoid synthesis, scavenger receptors activity and cell adhesion. These results seem to point to an improvement in health status, in which lymphocytes are less prone to produce chemokines and adhesion molecules and monocytes show reduced susceptibility to differentiate into foam cells. Overall, beneficial effects of n-3 PUFAs that have been described in vitro and in animal studies, were shown in vivo in human subjects in this study. This not only confirms that EPA and DHA elicits beneficial effects on inflammatory and atherogenic processes of elderly subjects, but also shows that PBMC gene expression profiles can be used to show effects of nutrition on human health status

Acute effects of different dietary fatty acids on the gene expression profiles of PBMCs of healthy young men

Acute effects of different dietary fatty acids on the gene expression profiles of peripheral blood mononuclear cells in healthy young men. A randomized cross-over study

Postprandial dietary lipid-specific effects on human peripheral blood mononuclear cell gene expression profiles

Dietary polyunsaturated fatty acids (PUFAs) have a variety of beneficial effects, and immune cells play an important role in these effects. The mechanisms of action of PUFAs are still not completely understood, but it is known that PUFAs can influence the expression of a broad set of genes

Muscarinic M3-receptors mediate cholinergic synergism of mitogenesis in airway smooth muscle

Muscarinic receptor agonists have been considered to act syner- and cytoskeletal reorganization has been proposed (4–6). gistically in combination with growth facors on airway smooth Furthermore, M2-receptors may stimulate nonselective catmuscle growth. Characterization of the proliferative responses ion channels through Gi/G(o) proteins, resulting in a rise in and of the receptor subtype(s) involved has not yet been stud- [Ca2�]i (7). ied. Therefore, we investigated mitogenesis induced by stimula- Muscarinic receptor agonists have been reported to be tion of muscarinic receptors, alone and in combination with mitogenic for human ASM cells, though at most modestly, stimulation by platelet-derived growth factor (PDGF). For this and to respond synergistically in combination with growth purpose, [ 3H]thymidine-incorporation was measured at differfactors (8, 9). Although carbachol-induced mitogenesis has ent culture stages in bovine tracheal smooth muscle cells. Funcbeen reported to be pertussis toxin (PTX)-sensitive (8, 10), tional muscarinic M3-receptors, as measured by formation of suggesting a role for the Gi-protein–coupled muscarinic M2inositol phosphates, were present in unpassaged cells, but were receptor, measurements were performed using human AS

The effects of sulfated secondary bile acids on intestinal barrier function and immune response in an inflammatory in vitro human intestinal model

Dysbiosis-related perturbations in bile acid (BA) metabolism were observed in inflammatory bowel disease (IBD) patients, which was characterized by increased levels of sulfated BAs at the expense of secondary BAs. However, the exact effects of sulfated BAs on the etiology of IBD are not investigated yet. Therefore, we aimed to investigate the effects of sulfated deoxycholic acid (DCA), sulfated lithocholic acid (LCA) and their unsulfated forms on intestinal barrier function and immune response. To this end, we first established a novel in vitro human intestinal model to mimic chronic intestinal inflammation as seen during IBD. This model consisted of a co-culture of Caco-2 and HT29-MTX-E12 cells grown on a semi-wet interface with mechanical stimulation to represent the mucus layer. A pro-inflammatory environment was created by combining the co-culture with LPS-activated dendritic cells (DCs) in the basolateral compartment. The presence of activated DCs caused a decrease in transepithelial electrical resistance (TEER), which was slightly restored by LCA and sulfated DCA. The expression of genes related to intestinal epithelial integrity and the mucus layer were slightly, but not significantly increased. These results imply that sulfated BAs have a minor effect on intestinal barrier function in Caco-2 and HT29-MTX-E12 cells. When exposed directly to DCs, our results point towards anti-inflammatory effects of secondary BAs, but to a minor extent for sulfated secondary BAs. Future research should focus on the importance of proper transformation of BAs by bacterial enzymes and the potential involvement of BA dysmetabolism in IBD progression

Bradykinin augments EGF-induced airway smooth muscle proliferation by activation of conventional protein kinase C isoenzymes

This study aims to investigate the effects of bradykinin, alone and in combination with growth factors on proliferation of cultured bovine tracheal smooth muscle cells. Bradykinin did not induce mitogenic responses by itself, but concentration-dependently augmented growth factor-induced [H-3]thymidine incorporation and cell proliferation. The bradykinin effect was mediated by bradykinin B? receptors, and not dependent on cyclo-oxygenase. Bradykinin-induced synergism with epidermal growth factor (EGF) could be suppressed by the protein kinase C (PKC) inhibitors GF 109203X (Bisindolylmaleimide 1; specific for conventional and novel PKCs) and Go 6976 (12-(2-Cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)-carbazole; specific for conventional PKCs). In addition, sole activation of PKC using Phorbol 12-myristate 13-acetate (PMA) was sufficient for a synergistic interaction with EGF. In contrast to bradykinin however, PMA was mitogenic by itself which was not at all affected by Go 6976, but abolished by GF 109203X. Bradykinin transiently activated the p42/p44 MAP kinase pathway, whereas PMA-induced activation of p42/p44 mitogen activated protein (MAP) kinase was sustained. Neither the combination of bradykinin and EGF nor that of PMA and EGF induced synergistic activation of p42/p44 MAP kinase, however. These results show that bradykinin B, receptor-stimulation augments growth factor-induced mitogenic responses of airway smooth muscle cells through activation of conventional PKC isozymes. In addition, the results show that PKC isozyme-specificity underlies stimulus-specific differences in mitogenic capacity for bradykinin and PMA. Published by Elsevier B.V