Mg2+ coordination in catalytic sites of F1-ATPase

Cytokines are hormone-like proteins which mediate and regulate inflammatory and immune responses. The purpose of this study was to investigate the effect of lipopolysaccharide (LPS) and inflammatory cytokines on regulation of interleukin-6 (IL-6) production by human gingival fibroblasts (HGF). The HGF cell lines used in this study, H-CL and F-CL, were established by the explant technique from healthy gingival tissue. Cultured cells were grown to confluency and incubated with various concentrations of LPS from Escherichia coli or Porphyromonas gingivalis or with the recombinant human cytokine tumor necrosis factor alpha (TNF-alpha), IL-1alpha, or IL-1beta. Culture supernatants were collected at various times and assessed for IL-6 production by enzyme-linked immunosorbent assay. Total RNA was isolated from the harvested cells and used to assess levels of IL-6 mRNA by the RNase protection assay. Both LPS preparations induced IL-6 production (1 to 4 ng of IL-6 per ml) by both HGF cell lines. Although TNF-alpha stimulated IL-6 production by HGF, > 10-fold-larger amounts were induced with IL-1alpha and IL-1beta. Furthermore, the addition of both IL-1alpha and TNF-alpha to cultured cells resulted in approximately 600- to 800-fold-higher levels of IL-6 than seen in control cultures, suggesting that these cytokines synergistically induced IL-6 production by HGF. IL-6 message in cultured cells was upregulated 20-fold by TNF-alpha, 1,000-fold by IL-1alpha and IL-1beta, and 1,400-fold by IL-1alpha plus TNF-alpha. IL-1alpha and TNF-alpha alone upregulate IL-6 production in a dose- and time-dependent fashion. The addition of IL-1alpha and TNF-alpha to cultured HGF cells resulted in a synergistic induction of IL-6 after 8 h of incubation and when greater than 10 pg of this combination per ml was used. Our studies show that inflammatory cytokines are hundreds of times more potent than LPS in stimulating IL-6 production by HGF.     

Effects of estrogen therapy of postmenopausal women on cytokines measured in peripheral blood

Estrogen replacement therapy (ERT) is known to prevent bone loss following the menopause, but the mechanism for this is unclear. Estrogen may suppress the secretion of certain bone-resorbing cytokines. The aim of this study was to assess the effect of ERT on the levels of cytokines measured in peripheral blood. We measured cytokines in 10 postmenopausal women (ages 56-59, 3-9 years since menopause) treated with ERT and 10 age-matched (54-59 years, 4-10 years since menopause) untreated women as controls. Samples of blood were taken and used for mononuclear cell cultures, whole blood (WB) cultures, and the separation of serum. The cultures were treated with lipopolysaccharide (LPS; 500 ng/ml) and hydrocortisone (10(-6) M). The conditioned medium from cultures and the serum were then assayed for interleukin-6 (IL-6), IL-1alpha IL-1beta, IL-1 IL-1ra, tumor necrosis factor alpha (TNF-alpha), and granulocyte macrophage colony stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. M-CSF and the soluble cytokine receptors soluble IL-6 receptor (sIL-6r) and soluble TNF receptor type 1 (sTNFr1) were also measured in serum and M-CSF in stimulated WB cultures. Measurements were corrected for mononuclear cell count. We also measured serum bone-specific alkaline phosphatase (ibAP) in all subjects. We found that LPS stimulated secretion of all cytokines both in WB and isolated cell cultures, and that this was attenuated by hydrocortisone. A significantly higher ratio of IL-1beta/IL-1ra (p = 0.02) in LPS stimulated WB cultures was seen in the untreated women. Levels of IL-1beta and IL-1alpha measured in WB cultures were lower and IL-1ra was higher in the ERT-treated group but these results were not significant. BAP was higher in the untreated group (p = 0.005) and correlated with IL-alpha/IL-1ra in the whole group (r = 0.49, p = 0.03). Results of other measurements showed no significant differences between groups. We conclude that estrogen may prevent bone loss following the menopause by altering the balance between IL-1beta and IL-1ra.     

In situ expression of cytokines in IgA nephritis

We studied mRNA and protein expression of interleukins (IL) and tumor necrosis factor (TNF) in renal tissues biopsied from 40 patients with IgA nephritis. Immunofluorescent staining with antibodies to IL-1 alpha, IL-1 beta, IL-6, IL-8, TNF-alpha, and TNF-beta was intense in the cytoplasm of cells in glomeruli, which were dual-stained with an anti-monocyte-macrophage antibody. In addition, moderate immunofluorescence for TNF-alpha, and weak staining for IL-1 alpha and IL-6 were occasionally found in resident glomerular cells. Immunoperoxidase-in situ hybridization dual-labeling revealed that IL-1 alpha, IL-6, and TNF-alpha mRNA signals were present in intraglomerular cells reactive with anti-monocyte-macrophage antibody, which further supported the immunofluorescent findings. Cells expressing IL-1 alpha, IL-1 beta, IL-6, IL-8, TNF-alpha, and TNF-beta were also observed in the interstitium. Most of these cells were also labeled with the anti-monocyte-macrophage antibody. The number of IL-1 alpha, IL-6, and TNF-alpha-positive cells infiltrating the glomerulus significantly correlated with mesangial hypercellularity. IL-8 and TNF-alpha-positive intraglomerular cells were correlated with the magnitude of proteinuria. The population of interstitial cells positive for IL-1 alpha, IL-6, IL-8, and TNF-alpha was associated with the grade of tubulointerstitial changes and proteinuria. There was no correlation between local IL-1 alpha, IL-6, and TNF-alpha expression in glomeruli or interstitium and serum or urinary levels of the respective cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo expression of interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, tumour necrosis factor-alpha and interferon-gamma in the fetal murine thymus

Cytokines are known to play a role in T-cell lymphopoiesis as potent growth or differentiation factors, but many experiments focusing on their role in the thymus have been conducted only in vitro. We have thus used frozen sections obtained from fetal thymuses of normal C57BL 6 mice to investigate by immunohistochemistry the presence of interleukin-1 beta (I4-1 beta), IL-2. IL-4. IL-6. interferon-7 (IFN-7) and tumour necrosis facor-alpha (TNF-alpha). The results reveal that apart from IL-2, which was not detected, all these cytokines display a time-dependent expression pattern in the normal fetal thymus. First, production of IL-4, IL-6 and TNF-alpha is detected around days 13 14; this is followed by a second wave on days 16 17, with a production of IL-1 beta, IL-4 and IL-6, and finally, just before birth (day 19), by a third wave of IL-1 beta, IL-4, IL-6, IFN-7 and TNF-alpha production. This supports the hypothesis that cytokines play a rote in T-cell lymphopoiesis.     

Interleukin-6 production in human fibroblasts derived from periodontal tissues is differentially regulated by cytokines and a glucocorticoid

Interleukin-6 (IL-6) is thought to be a major mediator of the host's defense against infection, and it regulates immune responses in inflamed tissue. In this study, we investigated the regulation of IL-6 production in human gingival fibroblasts (HGF) and human periodontal ligament fibroblasts (HPLF). Pro-inflammatory cytokines including interleukin (IL)-1 alpha, IL-1 beta and tumor necrosis factor (TNF)-alpha stimulated IL-6 production in HGF and HPLF in a time- and dose-dependent manner. This IL-1 alpha, IL-1 beta, or TNF-alpha-induced IL-6 production was enhanced, but the cAMP accumulation they induced was inhibited by the addition of indomethacin. This result suggests that endogenous prostaglandin E2 (PGE2) partially inhibits IL-1 or TNF-alpha-induced IL-6 production and that the enhancement of IL-6 production by IL-1 or TNF-alpha may not be caused through endogenous PGE2-induced cAMP-dependent pathway. Dexamethasone (DEX), a glucocorticoid which is a inhibitor of nuclear factor kappa B (NF-kappa B activation, markedly inhibited IL-1 (alpha or beta) or TNF-alpha-induced IL-6 production; so this production may be partially mediated through NF-kappa B. IL-1 (alpha or beta) and TNF-alpha enhanced IL-6 production synergistically. IL-6 production in HGF or HPLF stimulated with IL-1 beta was augmented by the addition of interferon (IFN)-gamma, but was slightly suppressed by the addition of IL-4. Endogenous IL-6 enhanced IL-1 (alpha or beta)-induced IL-6 production in the presence of IL-6 soluble receptor (IL-6sR). Accordingly, in inflamed periodontal tissues, gingival fibroblasts and periodontal ligament fibroblasts stimulated with pro-inflammatory cytokines such as IL-1 or TNF-alpha, may produce IL-6, and this production can be differentially modulated by endogenous PGE2, IL-6sR, T cell-derived cytokines such as IFN-gamma or IL-4, and glucocorticoids.     

Erratum to "Immunocytochemical detection of cytokines and chemokines in Langerhans cells and in vitro derived dendritic cells"

We have developed a direct immunocytochemical technique to identify cytokine and chemokine production in epidermal Langerhans cells (LC) and in vitro derived CD14-, CD1a+, CD83+, CD40+ dendritic cells (DC) at the single cell level. Formaldehyde fixation combined with saponin permeabilization preserved cellular morphology and generated a characteristic juxtanuclear staining signal due to the accumulation of cytokine to the Golgi organelle. This approach was used for the assessment of TNF-alpha, IL-6, IL-8, IL-10, IL-12, GM-CSF, MIP-1alpha, MIP-1beta and RANTES producing cells. In contrast, a diffuse cytoplasmic staining was evident for IL-1ra, IL-1alpha and IL-1beta production. IL-1ra and IL-1alpha were expressed in 10-25% of unstimulated cultured cells, while all the other cytokines were undetectable. IL-1ra, IL-1alpha and IL-1beta were also the dominating cytokines, expressed in up to 85% of the DC, after 3 h of LPS stimulation. A significantly lower number of cells (0-5%) synthesized TNF-alpha, IL-6, IL-10, IL-12 and GM-CSF. The incidence of chemokine producing cells (IL-8, RANTES, MIP-1alpha, MIP-1beta) peaked 10 h after LPS stimulation in up to 60% of the DC. Both immature CD83- and mature CD83+ DC as well as LC had a similar cytokine production pattern. Thus, in comparison to monocytes, LPS stimulation of DC generated a lower incidence of TNF-alpha, IL-6, IL-10 and IL-12 producing cells while IL-1 was expressed in a comparable number of cells.     

Localization of mRNA for inflammatory cytokines in radicular cyst tissue by in situ hybridization, and induction of inflammatory cytokines by human gingival fibroblasts in response to radicular cyst contents

The expression of mRNA encoding the inflammatory cytokines interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor alpha(TNF-alpha) have been examined in radicular cysts by in situ hybridization. Furthermore, the biological activity of the contents of radicular cysts (RCC) has been assayed by adding extracts of RCC to cultured human gingival fibroblasts (HGFs) and analyzing the culture medium for the release of inflammatory cytokines. In the epithelial layer, keratinocytes expressed all cytokine mRNAs examined at various levels. Basal layer cells expressed mRNA for each cytokine. In the subepithelial granulation tissue of the cysts, fibroblasts and macrophages expressed mRNA for IL-6, IL-8, IL-1beta and TNF-alpha mRNA at varying levels; especially clear expression of TNF-alpha and IL-1beta mRNA was detected on macrophages. The infiltrating lymphoid cells, largely composed of T cells and plasma cells, expressed these cytokine mRNAs, especially those encoding IL-6 and IL-8, at various levels. In vitro analysis indicated dose-dependent release of both IL-6 and IL-8 by HGFs in response to RCC. After heating to 100 degrees C for 10 min, RCC almost completely failed to stimulate IL-6 release from HGFs. Furthermore, anti-IL-1beta antibody (neutralization test) did not prevent the stimulation of IL-6 release by RCC. Significant amounts of IL-6 and IL-8 were detected in RCC in two cases, and a trace amount of IL-1beta was detected in one case. This study demonstrated the wide expression of mRNA encoding inflammatory cytokines in radicular cyst tissues, and RCC itself was capable of stimulating IL-6 and IL-8 production from HGFs.     

Regulated production of type I collagen and inflammatory cytokines by peripheral blood fibrocytes

We recently described a novel population of blood-borne cells, termed fibrocytes, that display a distinct cell surface phenotype (collagen+/CD13+/CD34+/CD45+), rapidly enter sites of tissue injury, and contribute to scar formation. To further characterize the role of these cells in vivo, we examined the expression of type I collagen and cytokine mRNAs by cells isolated from wound chambers implanted into mice. Five days after chamber implantation, CD34+ fibrocytes but not CD14+ monocytes or CD90+ T cells expressed mRNA for type I collagen. Fibrocytes purified from wound chambers also were found to express mRNA for IL-1beta, IL-10, TNF-alpha, JE/MCP, MIP-1alpha, MIP-1beta, MIP-2, PDGF-A, TGF-beta1, and M-CSF. The addition of IL-1beta (1-100 ng/ml), a critical mediator in wound healing, to fibrocytes isolated from human peripheral blood induced the secretion of chemokines (MIP-1alpha, MIP-1beta, MCP-1, IL-8, and GRO alpha), hemopoietic growth factors (IL-6, IL-10, and macrophage-CSF), and the fibrogenic cytokine TNF-alpha. By contrast, IL-1beta decreased the constitutive secretion of type I collagen as measured by ELISA. Additional evidence for a role for fibrocytes in collagen production in vivo was obtained in studies of livers obtained from Schistosoma japonicum-infected mice. Mouse fibrocytes localized to areas of granuloma formation and connective matrix deposition. We conclude that fibrocytes are an important source of cytokines and type I collagen during both the inflammatory and the repair phase of the wound healing response. Furthermore, IL-1beta may act on fibrocytes to effect a phenotypic transition between a repair/remodeling and a proinflammatory mode.     

A metalloproteinase inhibitor blocks the shedding of soluble cytokine receptors and processing of transmembrane cytokine precursors in human monocytic cells

A number of membrane-anchored cytokines and cytokine receptors are susceptible to yield soluble counterparts. Recently, peptide-hydroxamate metalloproteinase inhibitors have been reported to block the proteolytic processing of tumour necrosis factor (TNF)-alpha 55- and 75-kDa TNF receptors (TNF-R55 and TNF-R75), and interleukin (IL)-6R. In this report the authors studied the effect of an hydroxamate metalloproteinase inhibitor on the secretion of cytokines and the generation of cytokine soluble receptors by human myelomonoycytic cell lines and purified monocytes. Whereas secretion of cytokines lacking a transmembrane domain precursor (IL-1 alpha, IL-1 beta, IL-6 or IL-10) is either unaffected or augmented, shedding/secretion of transmembrane domain-containing cytokines and cytokine receptors [TNF-alpha, macrophage colony-stimulating factor (M-CSF), transforming growth factor (TGF)-alpha, stem cell factor (SCF), TNF-R55, TNF-R75, and IL-6R] was dramatically decreased in the presence of the metalloproteinase inhibitor. The diversity of sequences in the cleavage site of these proteins and differences found in the inhibitory concentration values suggest the existence of a metalloproteinase family displaying different substrate specificity. These results emphasize the important role of metalloproteinases as regulators of membrane expression and secretion of cytokines and cytokine receptors.     

Differential effects of interleukin 1-alpha (IL-1 alpha) or tumor necrosis factor-alpha (TNF-alpha) on motility of human melanoma cell lines on fibronectin

Interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) induce a motogenic response in a number of benign and malignant cells. We examined the chemokinetic effects of these cytokines on the cell migration of four melanoma cell lines on fibronectin using modified Boyden chambers and video-time lapse analysis. Flow cytometry analysis of IL-1 receptors, TNF receptors, and shifts in beta 1 integrin expression were correlated with the effects of these cytokines on cell migration on fibronectin. The four melanoma cell lines exhibited heterogeneous expression of types I and II IL-1 receptors as well as p60 TNF receptors. Scant p80 TNF receptor expression was detected on only one cell line. Three of four melanoma cell lines demonstrated type I IL-1 receptors by Western blotting. IL-1 alpha and TNF-alpha induced heterogeneous modulation of beta 1 integrin expression in the four melanoma cell lines tested; downward shift of the alpha 2, alpha 3, alpha 4, and beta 1 integrin subunits was detected among three of the melanoma cell lines as were upward shifts of the alpha 4, alpha 5, and alpha 6 integrin subunits among three of the melanoma cell lines. IL-1 alpha and TNF-alpha induced enhanced migration on fibronectin in one of the melanoma cell lines and were related to an upward shift in the alpha 4 and alpha 5 integrin subunit expression. Taken together, the findings indicate that expression of a particular receptor for IL-1 or TNF does not necessarily signal a motogenic response in melanoma cells, but induces heterogeneous shifts in beta 1 integrin expression. However, upregulation in alpha 4 and alpha 5 integrin subunits appears to relate to enhanced migration on fibronectin.     

Mutations of Arabidopsis in potential transduction and response components of the phototropic signaling pathway

IL-1 plays an important role in the pathophysiologic responses to infection and inflammation, in part by mediating its own production and that of other proinflammatory cytokines. However, the relative contribution of IL-1 alpha and IL-1 beta to the inflammatory response has not been well clarified. Using IL-1 beta-deficient (IL-1 beta -/-) mice, we investigated the specific role of IL-1 beta in the in vivo and in vitro response to LPS. No differences between IL-1 beta +/+ and IL-1 beta -/- mice were observed in circulating levels for IL-1 alpha, IL-6, or TNF-alpha after the systemic administration of either a low (5 micrograms/kg) or high (5 mg/kg) dose of LPS. IL-1 beta -/- mice also had a normal response to LPS in terms of activation of the hypothalamus-pituitary-adrenal axis, hypoglycemia, serum amyloid A production, and anorexia. IL-1 beta -/- mice were normally sensitive to the lethal effect of LPS and were protected against LPS toxicity when pretreated with low-dose LPS. However, in vitro, peritoneal macrophages from IL-1 beta -/- mice stimulated with LPS produced significantly less IL-1 alpha than macrophages from IL-1 beta +/+ mice (p < 0.05). No differences in IL-6 or TNF-alpha synthesis were observed between macrophages from IL-1 beta +/+ and IL-1 beta -/- mice. In summary, our results suggest that either IL-1 beta is not essential for the in vivo systemic response to LPS or that its role can be fulfilled by other cytokines with overlapping activities.     

Serum levels of cytokines in patients with colorectal cancer: possible involvement of interleukin-6 and interleukin-8 in hematogenous metastasis

Serum levels of interleukin-1 (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor (TNF-alpha), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured preoperatively in 24 patients with colorectal cancer. IL-1 beta was not elevated, IL-6 and IL-8 were markedly elevated, and GM-CSF was slightly elevated. TNF-alpha was not detected in most patients. Serum IL-6 levels correlated closely with serum IL-8 levels and with serum carbohydrate antigen (CA) 19-9 levels. Serum IL-6 levels were significantly higher in patients whose tumors exceeding 5.0 cm in diameter or spreading circumferentially. Serum IL-8 levels showed significant differences according to histological type, being lower in well differentiated adenocarcinoma compared to other types. Serum levels of IL-6 and IL-8 were significantly higher in patients with liver metastasis than in those without liver metastasis and serum levels of both these cytokines were also significantly higher in patients with lung metastasis than in those without lung metastasis. These results suggest that IL-6 and IL-8 may play an important role in the hematogenous metastasis of colorectal cancer.     

Cytokine profiles differ in newly recruited and resident subsets of mucosal macrophages from inflammatory bowel disease

BACKGROUND & AIMS: Most macrophages in the normal intestinal mucosa have a mature phenotype. In inflammatory bowel disease (IBD), a monocyte-like subset (CD14+ L1+) accumulates. The aim of this study was to characterize its potential with regard to cytokines. METHODS: Lamina propria mononuclear cells were adherence-separated, with or without depletion of CD14+ cells, and production of cytokines was investigated by bioassay, enzyme-linked immunosorbent assay, or immunocytochemistry. RESULTS: Tumor necrosis factor alpha (TNF-alpha), interleukin 1beta (IL-1beta), and IL-1 receptor antagonist were found mainly in cells positive for myelomonocytic L1. In undepleted IBD cultures, TNF-alpha, IL-1alpha and beta, and IL-10 were markedly up-regulated by pokeweed mitogen stimulation; IL-1alpha and beta and IL-10 were also up-regulated by stimulation of interferon gamma and lipopolysaccharide in combination. The latter stimulation had no effect on normal control or CD14-depleted IBD cultures. Indomethacin caused a marked increase of TNF-alpha, particularly in undepleted IBD cultures, whereas IL-10 and IL-4 decreased TNF-alpha and IL-1beta in both CD14+ and CD14 macrophages. CONCLUSIONS: In IBD mucosa, macrophages with a monocyte-like phenotype are primed for production of TNF-alpha and IL-1alpha/beta and may therefore be of significant pathogenic importance [corrected]. However, this CD14+ subset, as well as the mucosal resident macrophages, have preserved responsiveness to several down-regulatory factors such as the macrophage deactivators IL-10 and IL-4.     

Association of proteoglycan degradation with catabolic cytokine and stromelysin release from cartilage cultured with fibronectin fragments

Addition of fibronectin fragments to bovine articular cartilage explant cultures results in enhanced release of metalloproteinases and rapid cartilage proteoglycan (PG) degradation and loss. The chondrolysis begins with rapid PG degradation which markedly slows after 1 week. Preliminary observations suggest that catabolic cytokines mediate chondrolytic activities of the fibronectin fragments. The objectives of this work were to investigate the correlations between: (a) release of specific cytokines; (b) release of the metalloproteinase (MMP), stromelysin-1 (MMP-3); (c) release of the tissue inhibitor of MMPs, TIMP-1, and; (d) degradation and release of PG from cultured cartilage. We report that human articular cartilage cultured with an amino-terminal 29-kDa fragment (Fn-f) at 0.1 microM, released enhanced levels of TNF-alpha, IL-1beta, and IL-1alpha with peaks at Days 2, 3, and 9, respectively. MMP-3 release was elevated with a peak at Day 6 and a profile similar to that for the Fn-f-induced cartilage PG depletion. IL-6 release was enhanced within 2 days and continued at the same level throughout the culture period but this did not lead to enhanced release of TIMP-1, a known activity of IL-6. These data suggest that in the early chondrolytic events induced in cultured cartilage by Fn-f, enhanced MMP-3 release and maximal degradation and release of PG from cultured cartilage are kinetically associated with elevated release of the catabolic cytokines, TNF-alpha, IL-1beta, and IL-1alpha. Further, a later period of slowing PG loss and slowing MMP-3 release is associated with greatly slowed release of these cytokines, but prolonged release of IL-6. This model of cartilage damage may be useful for studies of the interplay between cytokines and the effects of combinations of cytokines on cartilage homeostasis.     

Low sensitivity of adrenal chromaffin cells to acetylcholine, neostigmine and oxotremorine in 21-day-old rats

To evaluate the immunological function of peripheral blood monocytes (PBMC) in psoriasis, we measured spontaneous production of the inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 from the PBMC of psoriasis patients, by enzyme linked immunosorbent assay (ELISA). The production of all three inflammatory cytokines by psoriatic PBMC was significantly higher than that by normal control PBMC. PBMC sampled from active psoriasis produced three cytokines significantly higher than samples from inactive psoriasis. In addition, IL-1beta and TNF-alpha production showed a positive relation to clinical severity, but IL-6 did not. TNF-alpha production increased much more than did the others. Therefore, the TNF-alpha to IL-1beta ratio was significantly higher, even in inactive psoriasis, than that of the normal control. In relation to focal infection, psoriatic PBMC sampled 3 h after a tonsillar provocation test increased cytokine production, compared with the level before provocation. The cases which responded to tonsillectomy or systemic methotrexate therapy, but not the non-responding cases, showed a significant decrease in PBMC cytokine productivity. These results strongly suggest that inflammatory cytokines, especially TNF-alpha, from monocytes are involved in the pathogenesis of psoriasis, and activated monocytes may work as an effective mediator of focal infection in skin lesions.