Cyclosporine A inhibits interleukin-8 production in a human colon epithelial cell line (HT-29)

Amniotic membrane matrix effects on calcineurin-NFAT-related gene expressions of SHED treated with VEGF for endothelial differentiation

The nuclear factor of activated T-cell (NFAT) signaling pathway is involved in angiogenesis following initiation by vascular endothelial growth factor (VEGF). A number of angiogenic genes have been associated with calcineurin in the NFAT pathway, forming a calcineurin-NFAT pathway. This study aims to investigate the involvement of four angiogenic genes within the calcineurin-NFAT pathway in the endothelial-like differentiation of stem cells from human exfoliated deciduous teeth (SHED) cultured on a human amniotic membrane (HAM) induced by VEGF. SHED were induced with VEGF for 24 h, then cultured on the stromal side of HAM. The cells were then further induced with VEGF until days 1 and 14. To understand the role of calcineurin, its potent inhibitor, cyclosporin A (CsA), was added into the culture. Results from SEM and H&E analyses showed SHED grew on HAM surface. Gene expression study of Cox-2 showed a drastically reduced expression with CsA treatment indicating Cox-2 involvement in the calcineurin-NFAT pathway. Meanwhile, IL-8 was probably controlled by another pathway as it showed no CsA inhibition. In contrast, high expression of ICAM-1 and RCAN1.4 by VEGF and CsA implied that these genes were not controlled by the calcineurin-NFAT-dependent pathway. In conclusion, the results of this study suggest the involvement of Cox-2 in the calcineurin-NFAT-dependent pathway while RCAN1.4 was controlled by NFAT molecule in endothelial-like differentiation of SHED cultured on HAM with VEGF induction.

The temporal expression, cellular localization, and inhibition of the chemokines MIP-2 and MCP-1 after traumatic brain injury in the rat

The expression of the neutrophil chemokine macrophage inflammatory protein-2 (MIP-2/CXCL2) and the monocyte chemokine monocyte chemotactic protein-1 (MCP-1/CCL2) have been described in glial cells in vitro but their origin following TBI has not been established. Furthermore, little is known of the modulation of these chemokines. Chemokine expression was investigated in male Sprague-Dawley rats following moderate lateral fluid percussion injury (LFPI). At 0, 4, 8, 12, and 24 h after injury, brains were harvested and MIP-2/CXCL2 and MCP-1/CCL2 levels measured by ELISA. To investigate the inhibition of chemokine expression a second cohort of animals received dexamethasone (1-15mg/kg), FK506 (1mg/kg), or vehicle, systemically, immediately after injury. These animals were sacrificed at the time of peak chemokine expression. A third cohort of animals was also sacrificed at the time of peak chemokine expression and immunohistochemistry performed for MIP-2/CXCL2 and MCP-1/CCL2. Following LFPI, chemokines were increased in the ipsilateral hemisphere, MIP-2/CXCL2 peaking at 4 h and MCP-1/CCL2 peaking at 8-12 h post-injury. Dexamethasone significantly reduced cortical MCP-1/CCL2, but not MIP-2/CXCL2 concentrations. FK506 did not inhibit chemokine expression. In undamaged brain, chemokine expression was localized to cells with a neuronal morphology. For MIP-2/CXCL2 this was supported by double staining for the neuronal antigen NeuN. In contused tissue, increased MIP-2/CXCL2 and MCP-1/CCL2 staining was visible in cells with the morphology of degenerating neurons. MIP-2/CXCL2 and MCP-1/CCL2 are increased after injury, and neurons appear to be the source of this expression. Chemokine expression was selectively inhibited by dexamethasone. The implications of this are discussed.

Macrolides inhibit IL17-induced IL8 and 8-isoprostane release from human airway smooth muscle cells

Lung transplantation is hampered by bronchiolitis obliterans syndrome (BOS), although recently azithromycin treatment has a published response rate of about 42% in patients with established BOS. We linked this improvement to a reduction in airway neutrophilia and IL8. In the present study, we further investigated the intracellular mechanisms of azithromycin, looking at the possible involvement of mitogen-activated-protein kinases (MAPK) and oxidative stress. Simultaneously, currently used immunosuppressive agents were investigated. Human primary airway smooth muscle cells were stimulated with IL17 and incubated with increasing concentrations of steroids, immunosuppressive agents (tacrolimus, cyclosporine and rapamycin) or macrolides (erythromycin and azithromycin). We measured supernatant IL8 protein, 8-isoprostane and cell lysate MAPK. IL17-induced IL8 production was decreased by both erythromycin and azithromycin. In nonstimulated condition, IL8 production only increased at the highest dose of azithromycin. Dexamethasone failed to attenuate IL8 production, whereas immunosuppressive agents significantly increased IL8 production in both IL17-stimulated and nonstimulated conditions. 8-isoprostane production and MAPK activation proved to be decreased by the macrolides. We conclude that macrolides (but not steroids/immunosuppressive agents) inhibit IL17-induced IL8 production in human primary airway smooth muscle cells via a reduction in MAPK activation and 8-isoprostane production. In BOS patients, these phenomena may explain the anti-inflammatory effects of azithromycin.

Increased expression of MIP-3alpha/CCL20 in peripheral blood mononuclear cells from patients with ulcerative colitis and its down-regulation by sulfasalazine and glucocorticoid treatment

CCL20 expression is known to increase in the mucosal tissues of inflammatory bowel diseases (IBDs). Moreover, the discovery of Nod2 as the IBD1 susceptibility gene has underscored the significance of blood mononuclear cells in IBD pathogenesis.

METHODS

This study addresses whether CCL20 expression is similarly altered in peripheral blood mononuclear cells (PBMCs) of patients with ulcerative colitis (UC), a major type of IBD in Korea.

RESULTS

Expression of CCL20 was significantly up-regulated in the PBMCs of patients with UC compared with those of normal healthy controls. Interestingly, untreated UC groups expressed higher levels of CCL20 mRNA than either treated UC or normal control groups, suggesting that CCL20 could be modulated by anti-inflammatory drugs. Accordingly, a strong association between CCL20 levels and disease activity index was observed. Supporting these findings, results from a 3-month follow-up study revealed that the UC groups treated with 5-aminosalicylic acid and glucocorticoid exhibited dramatic decreases of CCL20 mRNA in PBMCs, accompanied by ameliorated disease states. Moreover, tumor necrosis factor-alpha- or interleukin-1beta-induced CCL20 secretion was greatly diminished by 5-aminosalicylic acid and/or glucocorticoid treatment of human intestinal epithelial HT-29 cells. Of note, CCR6 cell populations were significantly reduced in the blood of severe patients with UC compared with normal controls, whereas no significant changes in CCR6 cell populations were observed in the blood of patients with mild UC or acute colitis.

CONCLUSIONS

Collectively, these findings suggest that CCL20 expression in blood mononuclear cells is associated with altered immune and inflammatory responses in patients with UC.

Calcineurin inhibitor effects on growth and phenotype of human airway epithelial cells in vitro

Calcineurin inhibitors (CIs) cyclosporin and tacrolimus form the basis for immunosuppression in lung transplantation, yet also exert biological effects on nonlymphoid tissue. With the advent of inhaled cyclosporin, we hypothesize that the airway epithelium is also subject to CI effects at high doses. The aim of this study was to identify human tracheobronchial epithelial cell (hTBEC) calcineurin gene expression and quantify effects of CIs on hTBEC growth, interleukin-1-beta stimulated IL-8 production and hTBEC phenotype. Cyclophillin B and FK-associated binding protein, calcineurin A (alpha and beta), and NFATC3 and NFAT5 were detected in hTBEC cultures by RT-PCR. Acute and chronic cyclosporine treatment 1000 ng/mL significantly inhibited hTBEC proliferation, while tacrolimus did not (range of 10 ng/mL to 1000 ng/mL for acute treatment, 50 ng/mL for chronic treatment). Cyclosporin at 10,000 ng/mL significantly increased LDH release by well-differentiated hTBEC cultures (n = 6) and trended towards significance at 1000 ng/mL. IL1-beta stimulated IL-8 production was significantly increased in rapidly growing hTBEC cultures (n = 8) treated with cyclosporin (p = 0.049). Prolonged treatment of well-differentiated hTBECs at air-liquid-interface (ALI) with cyclosporin 1000 ng/mL significantly reduced intact multilayered mucociliary epithelium (p = 0.009). Inhibition of hTBEC growth, stimulation of IL-8 production and long-term effects on mucociliary phenotype and intact multi-layered epithelium suggest that cyclosporin may have a direct toxic effect on airway epithelium after transplantation.

Cyclosporin A enhances interleukin-8 expression by inducing activator protein-1 in human aortic smooth muscle cells

OBJECTIVE

Cyclosporin A (CsA) and tacrolimus (FK506) are widely used as immunosuppressants. However, their use has been hampered by various adverse effects, such as acceleration of atherosclerosis. Interleukin (IL)-8, a chemotactic cytokine, plays an important role in pathogenesis of atherosclerosis. We thus investigated whether synthesis of IL-8 from primary human aortic smooth muscle cells is influenced by CsA and FK506.

METHODS AND RESULTS

Northern blot analysis revealed that CsA increased IL-8 mRNA level and enhanced its increase by epidermal growth factor or tumor necrosis factor-alpha. In contrast, FK506 had no effect on the mRNA level. IL-8 accumulation in culture media was also increased by CsA. Stability of IL-8 mRNA was not affected by CsA, whereas luciferase reporter gene assay using the human IL-8 promoter revealed that CsA significantly augmented the promoter activity. Electrophoretic mobility shift assay showed that binding activity of activator protein (AP)-1 was increased by CsA, and introduction of a mutation into the AP-1 site in the promoter abolished its CsA-dependent activation. The increased AP-1 binding activity was accompanied by c-Fos synthesis.

CONCLUSIONS

CsA stimulates synthesis of IL-8 via activation of AP-1 in human aortic smooth muscle cells, providing a novel aspect of biological effects of CsA on the cells.

Cyclosporine inhibition of vascular endothelial growth factor production in rheumatoid synovial fibroblasts

OBJECTIVE

To determine the antiangiogenic effect of cyclosporin A (CSA) in rheumatoid arthritis (RA).

METHODS

We investigated the effect of CSA on the production of vascular endothelial growth factor (VEGF) by rheumatoid synovial fibroblasts. Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissues of RA patients, and cultured in the presence of CSA. The production of VEGF by FLS was measured in culture supernatants by enzyme-linked immunosorbent assay. The VEGF messenger RNA (mRNA) expression and activator protein 1 (AP-1) binding activity for VEGF transcription were determined by polymerase chain reaction and electrophoretic mobility shift assay, respectively.

RESULTS

CSA dose-dependently inhibited both constitutive and transforming growth factor beta-induced VEGF production at the protein and mRNA levels. The suppressive action of CSA on VEGF synthesis was calcineurin dependent, as evidenced by a comparable inhibition by FK-506. Agonists of cAMP, 3-isobutyl-1-methylxanthine and N-2-O-dibutyryl-cAMP, mimicked the effect of CSA on VEGF production, while a cAMP antagonist, 2',3'-dideoxyadenosine, abrogated the effect of CSA. A gel mobility shift assay showed that the inhibitory effect of CSA was associated with decreased AP-1 binding activity to the VEGF promoter, in a cAMP-dependent manner.

CONCLUSION

CSA may exert an antiangiogenic effect by inhibiting AP-1-mediated VEGF expression in rheumatoid synovial fibroblasts.

Suppressive effects of cyclosporine A on neutrophils and T cells may be related to therapeutic benefits in patients with steroid-resistant ulcerative colitis

An intravenous infusion of cyclosporine A (CsA) shows clinical benefits in patients with steroid-resistant ulcerative colitis (UC). To clarify its mechanisms, we investigated the ability of CsA to inhibit the functions of neutrophils and T cells. The cytotoxic activity by mucosal T cells was analyzed by anti-CD3-triggered cytotoxicity after lamina propria mononuclear cells were cultured with recombinant interleukin (IL)-2. The chemotactic response, the generation of superoxide, and the production of chemokines, IL-8, and macrophage inflammatory protein-1alpha by neutrophils were examined using a multiple-well chamber assay, a chemiluminescence method, and an enzyme-linked immunosorbent assay (ELISA), respectively. Mucosal chemokine activity was determined by an ELISA using the organ culture supernatant of mucosal biopsy tissues. Pretreatment with CsA caused consistent inhibitions of cytotoxic activity by mucosal T cells and chemotactic migration, superoxide generation, and chemokine production by neutrophils mostly in a dose-dependent manner. In patients who received an intravenous infusion of CsA, mucosal chemokine activity decreased after therapy in parallel with decreases in the numbers of neutrophils and mononuclear cells in the biopsy tissues. These results suggest that suppressive effects of CsA on neutrophils and T cells may be related to therapeutic benefits in patients with steroid-resistant UC.

Medium-chain fatty acids stimulate interleukin-8 production in Caco-2 cells with different mechanisms from long-chain fatty acids

BACKGROUND AND AIM

It has been suggested that dietary fat exacerbates intestinal inflammation. We investigated the effect of fatty acids on interleukin (IL)-8 production in a human intestinal epithelial cell line (Caco-2).

METHODS

The cells were cultured as monolayers on microporous membranes in culture inserts. Oleic acid (OA), capric acid (CA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were applied to the apical compartment of Caco-2 cell monolayers. The concentration of IL-8 in the basolateral medium was measured by using enzyme-linked immunosorbent assay, and the expression of IL-8 mRNA was measured by using competitive reverse transcription--polymerase chain reaction. Protein kinase C inhibitors (GF109203X and calphostin C) and H-7 (a protein kinase inhibitor) were used to study the mechanisms by which IL-8 production is stimulated.

RESULTS

Both OA and CA enhanced IL-8 production (approximately fivefold), whereas DHA and EPA did not. Both OA and CA also enhanced IL-1-induced IL-8 production. The onset of OA-induced IL-8 production was delayed compared with that of CA-induced IL-8 production. Both OA and CA enhanced IL-8 mRNA expression (approximately fivefold) after 6 and 3 h, respectively. The protein kinase inhibitor (H-7) reduced both OA- and CA-induced IL-8 production by 88.0 and 85.9%, respectively. The protein kinase C inhibitors (GF109203X and calphostin C) reduced OA-induced IL-8 production by 29.3 and 54.5%, respectively, but showed no effect on CA-induced IL-8 production.

CONCLUSIONS

These findings suggest that not only OA but also CA stimulates IL-8 production in intestinal epithelial cells, and the mechanisms of action differ between OA and CA.

Cellular differentiation causes a selective down-regulation of interleukin (IL)-1beta-mediated NF-kappaB activation and IL-8 gene expression in intestinal epithelial cells

Interleukin (IL)-1beta signals through various adapter proteins and kinases that lead to activation of numerous downstream targets, including the transcription factors including NF-kappaB. In this study, we analyzed and characterized the effect of the differentiation of intestinal epithelial cells on IL-1beta-mediated NF-kappaB activation and IL-8 gene expression. We report that IL-8 mRNA accumulation and protein secretion were down-regulated in IL-1beta- and lipopolysaccharide-stimulated differentiated HT-29 cells (HT-29/MTX, where MTX is methotrexate) compared with undifferentiated cells (HT-29/p), whereas no differential effects were found following tumor necrosis factor (TNF)-alpha or phorbol myristate acetate stimulation. Cross-linking and affinity binding studies reveal that IL-1beta exclusively binds the type I receptor (IL-1RI) and not IL-1RII in both HT-29/p and HT-29/MTX cells. IL-1beta-mediated IkappaB kinase and c-Jun N-terminal kinase (JNK) activity were both diminished in differentiated HT-29 cells. DNA binding activity in differentiated HT-29 cells relative to HT-29/p cells was strongly reduced following IL-1beta exposure but not after TNF-alpha stimulation. The proximal IL-1 signaling molecule IL-1 receptor-associated kinase was not degraded in IL-1beta-stimulated HT-29 cells, in contrast to Caco-2 cells. kappaB-luciferase reporter gene activity was 16-fold higher following TNF receptor-associated factor-6 transfection after IL-1beta stimulation in HT-29/MTX cells. We conclude that cellular differentiation of HT-29 cells selectively impairs the IL-1beta signaling pathway inhibiting both NF-kappaB and JNK activity in response to IL-1beta. This relative unresponsiveness to IL-1beta may represent an important regulatory mechanism of differentiated intestinal epithelial cells.

Modulation of CFTR gene expression in HT-29 cells by extracellular hyperosmolarity

Hypertonicity has pleiotropic effects on cell function, including activation of transporters and regulation of gene expression. It is important to investigate the action of hypertonicity on cystic fibrosis gene expression because cystic fibrosis transmembrane conductance regulator (CFTR), the cAMP-regulated Cl(-) channel, regulates ion transport across the secretory epithelia, which are often in a hypertonic environment. We found that adding >150 mosmol/l NaCl, urea, or mannitol to the culture medium reduced the amount of CFTR mRNA in colon-derived HT-29 cells in a time-dependent manner. Studies with inhibitors of various kinases [H-89 (protein kinase A inhibitor), bisindolylmaleimide (protein kinase C inhibitor), staurosporine (serine/threonine kinase inhibitor) and herbimycin A (tyrosine kinase inhibitor), SB-203580 and PD-098059 (mitogen-activated protein kinase inhibitors)] showed that CFTR gene expression and its decrease by added NaCl required p38 kinase cascade activity. The CFTR gene activity is regulated at the transcriptional level, since adding NaCl diminished the luciferase activity of HeLa cells transiently transfected with the CFTR promoter. This regulation requires protein synthesis. The complexity of the reactions involved in blocking CFTR gene transcription by NaCl strongly suggests that the decrease in CFTR mRNA is part of a general cell response to hyperosmolar stress.