Differential effects of IL-10 on prostaglandin H synthase-2 expression and prostaglandin E2 biosynthesis between spleen and bone marrow macrophages

Different populations of mononuclear phagocytes (MO) show considerable diversity of cellular function including prostaglandin E2 (PGE2) biosynthesis. Certain bacterial components enhance PGE2 biosynthesis differentially in selected populations of MO. Interleukin (IL)-10 is proposed to inhibit modulation of PGE2 biosynthesis by down-regulating prostaglandin G/H synthase-2 (PGHS-2) expression. To assess whether IL-10 regulates PGE2 biosynthesis and PGHS-2 expression, splenic and bone marrow MO were isolated from IL-10-deficient (IL-10(-/-)), C57Bl/6 [wild-type (WT) control], and Balb/c (comparison control) mice and were treated with lipopolysaccharide (LPS) and/or interferon-gamma (IFN-gamma) as a model of bacterial inflammation. LPS-induced PGHS-2 expression was similar for splenic MO isolated from the three strains of mice. However, PGE2 released by LPS-treated splenic MO was significantly higher in IL-10(-/-) and Balb/c than in WT cells. In the presence of LPS and IFN-gamma, PGHS-2 expression and PGE2 release by IL-10(-/-) and Balb/c splenic MO were enhanced compared with stimulation with LPS alone or IFN-gamma alone. However, there was no significant increase in PGE2 release from WT splenic MO treated with LPS plus IFN-gamma despite increased PGHS-2 expression. In sharp contrast, PGHS-2 expression and PGE2 release by bone marrow MO were greatly enhanced in IL-10(-/-) cells compared with control cells. Our results indicate that IL-10 regulation of MO PGE2 biosynthesis and PGHS-2 expression is compartment-dependent and that PGE2 production is not linked directly to PGHS-2 levels. Furthermore, our findings emphasize strain-specific differences between C57Bl/6 and Balb/c mice, and Balb/c appears more similar to the IL-10(-/-) than to the C57Bl/6 with respect to prostanoid production.     

Topical glucocorticoids application induced an augmentation in the expression of IL-1α while inhibiting the expression of IL-10 in the epidermis in murine contact hypersensitivity

The repeated application of glucocorticoids (GC) on the skin augmented the inflammatory response of both allergic and irritant contact dermatitis in our studies. In order to further clarify the mechanism of such an augmentation of contact hypersensitivity (CHS), we investigated the modulatory effects of cytokines in the epidermis after the administration of GC at challenged sites in CHS. Diflucortolone valerate was applied to BALB/c mice on alternate days for a total of nine times. On day 12, they were contact sensitized with dinitrofluorobenzene (DNFB). Next, on day 17, one day after the last application of GC, they were challenged with DNFB on the ear. The whole challenged ear lobes were removed after a hapten challenge and then were analysed by the RT-PCR method or underwent an immunohistochemical analysis. To clarify the modulatory effects of cytokines in vivo, DNFB sensitized mice pre-treated with GC were injected with rIL-10, IL-1 receptor antagonist (ra) and anti-IL-1alpha monoclonal antibody (mAb) and thereafter were challenged with DNFB. A RT-PCR analysis has demonstrated IL-10 mRNA to be detected in the challenged skin of non-GC-pretreated mice but not in that of GC-pre-treated mice after challenge. On the other hand, the expression of IL-1alpha mRNA in the challenged skin of mice pretreated with GC was more strongly detected that that in mice without GC-pretreatment. Furthermore, an immuno-histochemical analysis in the challenge showed the expression of IL-10 in the skin showed the expression of IL-10 in the challenged epidermis of the non-GC-pretreated mice but not in the GC-pretreated mice and IL-1alpha was also strongly expressed in the epidermis of the GC-pretreated mice. A subcutaneous injection of anti-IL-1alpha mAb or IL-1 ra inhibited the augmented CHS reaction in the GC-pretreated mice. A subcutaneous injection of rIL-10 also inhibited the augmentation of the CHS reaction in the GC-pretreated mice; however, no such inhibition was observed in the non-GC-pretreated mice. These results indicated that both an up-regulation of IL-1alpha production and the inhibition of the IL-10 production in the epidermis at the challenged skin sites in the GC-pretreated mice appear to play a critical role in the GC-induced augmentation of murine CHS.     

Splenic PGE2-releasing macrophages regulate Th1 and Th2 immune responses in mice treated with heat-killed BCG

Hosts infected with low doses of mycobacteria develop T helper cell type 1 (Th1) immunity, but at relatively higher doses, a switch to Th2 immunity occurs. Prostaglandin E2 (PGE2) is a proposed mediator of the Th1-to-Th2 shift of immune responses, and mycobacterial products induce PGE2-releasing macrophages (PGE2-M?) in the mouse spleen in a dose-dependent manner. Splenic PGE2-M ? from Balb/c mice, given 0.01 or 1 mg heat-killed (HK) Mycobacterium bovis bacillus Calmette-Guerin (BCG) intraperitoneally (i.p.), were characterized by the ex vivo release of PGE2 (>10 ng/10(6) cells), cytokine production, and expression of PGG/H synthase (PGHS)-1, PGHS-2, cytosolic PGE synthase (PGES), and microsomal PGES-1. At Day 14 after the treatment, mice treated with 1 mg, but not 0.01 mg, BCG had increased levels of PGHS-2+ PGE2-M?, total serum immunoglobulin E (IgE), and serum IgG1 antibodies (Th2 responses) against heat shock protein 65 and purified protein derivative. Cultures of spleen cells isolated from these mice expressed interleukin (IL)-4 and IL-10 in recall responses. Treatment of mice receiving 1 mg BCG with NS-398 (a PGHS-2 inhibitor, 10 mg/kg i.p., daily) resulted in enhanced interferon-gamma (IFN-gamma) production with reduced IL-4 and IL-10 production in recall responses. This treatment also resulted in decreased total serum IgE levels. Treatment of C57Bl/6 mice with HK-BCG (0.5 mg dose) also induced a mixture of Th1 and Th2 responses, although IFN-gamma production was markedly increased, and IL-4 was decreased compared with Balb/c mice. Thus, our results indicate that by 14 days following treatment of mice with high doses of HK-BCG, splenic PGE2-M? formation is associated with a PGHS-2-dependent shift from Th1-to-Th2 immune responses.     

Myometrial prostaglandin E2 synthetic enzyme mRNA expression: spatial and temporal variations with pregnancy and labour

We have investigated the hypothesis that the expression of the enzymes involved in PGE(2) synthesis in the human uterus is co-ordinated. We have studied (i) the mRNA expression of the enzymes involved in PGE(2) synthesis [phospholipases (cPLA(2) and sPLA(2)), prostaglandin H synthase (PGHS)-2 and PG E synthases (PGES-1 and -2)] and their relationship to the expression of inflammatory cytokines in samples of myometrium obtained from pregnant women undergoing caesarean section (LSCS) either before or after the onset of labour at or before term; and (ii) the effect of IL-1beta, IL-6, TNF-alpha, PGE(2) and stretch on PGE(2) enzyme mRNA expression. We found that cPLA(2), sPLA(2) and PGHS-2 mRNA expression were greater in labour samples; cPLA(2), sPLA(2), PGHS-2, PGES-1 and -2 mRNA expression were greater in lower- than upper-segment samples; and there was no effect of gestational age. PGHS-2 mRNA levels correlated with those of PGES-1, cPLA(2), IL-1beta and IL-8; PGES-1 mRNA levels correlated with those of IL-1beta, IL-8 and cPLA(2). In primary cultures of uterine myocytes, cPLA(2) mRNA expression was increased by IL-1beta and IL-6; PGHS-2 mRNA expression was increased by IL-1beta, PGE(2) and stretch; and PGES-1 mRNA expression was increased by IL-1beta only. These data show that labour is associated with increased expression of the enzymes involved in PGE(2) synthesis and their expression is greater in the lower uterine segment. The presence of associations between the levels of PGE(2) enzyme mRNA expression and the effects of IL-1beta suggest that their expression is co-ordinated and that IL-1beta is the responsible factor.     

Interleukin-1 stimulates human uterine prostaglandin production through induction of cyclooxygenase-2 expression

PROBLEM: Uterine infection occurs in as much as 20% of preterm labor and results in increased decidual cytokines. The objective of this study was to examine the effect of interleukin-1 (IL-1) and the cyclooxygenase-2 (COX-2) inhibitor, NS-398, on myometrial prostaglandin (PG) production and COX-2 expression. METHOD OF STUDY: Human uterine myocytes were stimulated with IL-1 (0-50 ng/mL) over 24 hr. PGE2, PGF2alpha, and 6-keto F1alpha were measured by enzyme-linked immunosorbent assay. Both COX-1 and COX-2 proteins and mRNA were measured by western and northern blot, respectively. RESULTS: IL-1 increased PG production beginning at 6 hr, COX-2 protein increased beginning at 4 hr and continued to increase at 24 hr. COX-2 mRNA increased at 2 hr and peaked at 4 hr. NS-398 blocked PG production but had no effect on COX-2 protein or mRNA. CONCLUSIONS: IL-1 increases PG production by myometrium by increased COX-2 expression. NS-398 completely blocks IL-1-induced PG production. With intrauterine infection, IL-1 may induce labor through the autocrine production of uterotonic PGs.     

Heterozygous α-antichymotrypsin and PiZ (α1-antitrypsin deficiency

In a case-control study we compared the prevalence of heterozygous deficiency of two closely related anti-neutrophil protease inhibitors, alpha 1-antitrypsin and alpha 1-antichymotrypsin, in 172 consecutive children with asthma. In a cohort study the clinical spectrum and severity were compared. On the basis of family studies 5/172 (2.9%) were classified as heterozygotes for alpha 1-antichymotrypsin deficiency, a high prevalence compared with that of an unselected adult population (prevalence ratio 4.5 (1.7-11.9), P less than 0.005). This finding suggests that the carrier state of this rare allele (prevalence 0.64%) may predispose to asthma in children. Among these heterozygous patients the prevalence of positive RAST tests for foodstuffs was significantly increased (prevalence ratio 4.8 (1.7-13.2), P less than 0.005) and 2/5 manifested food allergy with Quincke oedema. Either the PiMZ or SZ phenotype of alpha 1-antitrypsin deficiency was found in 12 (7.0%) of the 172 patients, a prevalence similar to that of a normal population (prevalence ratio 1.3 (0.67-2.6), P = 0.44). However, the asthma was more severe among the Z allele carriers, judged by the number of hospital admissions, compared with the non-Z asthmatic children (mean 2.92 vs. 1.72, P less than 0.05). The results indicate that heterozygous deficiency of protease inhibitors directed against neutrophil proteases may affect the severity and clinical spectrum of childhood asthma, and to some degree be predisposing.     

Induction of Interleukin 1α (IL-1α) and IL-1β mRNA Expression and Cellular IL-1 Production by Anti-HLA-DR Antibodies in Human Monocytes

We studied the role of HLA class II antigens in the regulation of interleukin 1 (IL-1) production in human monocytes. Monocytes were cultured with monoclonal anti-HLA-DR antibodies for 24 h after which cellular (i.e. intracellular and membrane-associated) IL-1 production, IL-1 secretion, and the expression of IL-1 alpha and IL-1 beta mRNA were determined. One of the anti-HLA-DR antibodies tested (anti-HLA-DR, Becton Dickinson) clearly induced IL-1 alpha and IL-1 beta mRNA expression and cellular IL-1 production. The other anti-HLA-DR antibody tested (OKIa1, Ortho) had no effect on IL-1 production. The stimulatory effect of anti-HLA-DR was enhanced by IFN-gamma in both fresh and aged monocytes. A synergistic effect by anti-HLA-DR and suboptimal doses of LPS (1 ng/ml) on both cellular IL-1 production and secretion was also demonstrated. The possibility of contaminating LPS causing the IL-1-inducing effect of anti-HLA-DR was excluded by the inability of polymyxin B to abolish the anti-HLA-DR-induced IL-1 production.     

Decidualization and maintenance of a functional prostaglandin system in human endometrial cell lines following transformation with SV40 large T antigen

Prostaglandins (PGs) are key regulators of reproductive function and associated pathologies. We have established stable endometrial stromal and epithelial cell lines with SV40 large T antigen (TAG) as a model to study PG action in the human endometrium. Two clones for each cell type were selected for rapid growth, PG production and response to interleukin-1beta (IL-1beta). The resulting stromal (HIESC) and epithelial (HIEEC) cells retain their characteristics for at least 40 population doublings (PDs). The selected clones express progesterone (PR) and estrogen receptor-alpha (ER-alpha) at both mRNA and protein levels. By contrast, with the existing known human endometrial cell lines Ishikawa and KLE, HIESC and HIEEC increase their production of PGF2alpha and PGE2 and cyclooxygenase (COX)-2 protein expression in response to IL-1beta. The latter cells also express the main biosynthetic enzymes involved in PG production, cytosolic phospholipase A2 (PLA2), COX-1 and COX-2, PGF synthase and PGE synthase and the corresponding EP2, EP3, EP4 and FP receptors. The selective COX-2 inhibitor NS-398 completely inhibits the increased production of PGs induced by IL-1beta in both cell types, whereas dexamethasone (DEX) exerts a stronger inhibition in HIESC than in HIEEC. The latter observation may be related to the higher expression of COX-1 measured in HIEEC. On the basis of the present characterization and previous determination of corresponding primary cell cultures, HIESC and HIEEC appear appropriate to study the contribution of PGs in the regulation of human endometrium function and associated pathologies.     

Induction of Microsomal Prostaglandin E Synthase-1 in Human Gingival Fibroblasts

It is well established that prostaglandin E2 (PGE2) plays an important role in inflammatory diseases including periodontitis. Previously we have reported that the inflammatory mediators interleukin-1beta, (IL-1beta) and tumor necrosis factor alpha (TNFalpha) stimulate PGE2 synthesis by inducing mRNA expression of cyclooxygenase-2 (COX-2) in human gingival fibroblasts. In present study the involvement of microsomal prostaglandin E synthase-1 (mPGES-1) in relation to PGE2 production was investigated. The results showed that IL-1beta as well as TNFalpha induced mPGES-1 mRNA and protein expression accompanied by enhanced PGE2 production in gingival fibroblasts. The anti-inflammatory steroid dexamethasone (DEX) inhibited mPGES-1 mRNA and protein expression as well as PGE2 production induced by IL-1beta or TNFalpha. The COX-2 specific inhibitor, celecoxib, in contrast to the nonspecific COX inhibitor, indomethacin, markedly reduced mPGES-1 expression induced by IL-1beta. The results demonstrate that mPGES-1 regulates PGE2 production in gingival fibroblasts stimulated by inflammatory mediators IL-1beta and TNFa. This novel pathway may be a potential target for treatment strategies of periodontal disease.     

Human Peripheral Blood-Derived Dendritic Cells do not Produce Interleukin 1α, Interleukin 1β, or Interleukin 6

Little is known about the non-antigen-specific signals delivered to T cells by dendritic cells (DC). Because several monocyte-derived factors like interleukins 1 alpha, 1 beta, and 6 (IL-1 alpha, IL-1 beta, and IL-6) enhance the T-cell proliferative responses, we studied the production of the above-mentioned cytokines by DC separated from human peripheral blood. The intracellular expression of the proteins (IL-1 alpha and IL-6) was studied at a single-cell level using an immunolabelling technique. The supernatants and cell lysates were studied with ELISA (IL-1 alpha and IL-1 beta). Northern blotting analysis was used to quantitate the mRNA levels. Several approaches were taken to stimulate the production of IL-1 alpha, IL-1 beta, and IL-6 by DC. These included the incubation of the DC in the presence of either LPS, rIL-1, or monoclonal anti-HLA-DR antibody, or the stimulation of cells with resting allogeneic T cells. None of the stimuli was able to induce the production of IL-1 alpha, IL-1 beta, or IL-6 by DC, whereas LPS-stimulated monocytes were strong producers of these mentioned cytokines and expressed the respective mRNA. Thus we concluded that IL-1 alpha, IL-1 beta, and IL-6 are primarily monocyte-derived factors and that these factors are not needed or produced during the activation of resting T cells by DC.     

Expression of pro-inflammatory cytokines in mouse blastocysts during implantation: modulation by steroid hormones

PROBLEM: Expression and hormonal regulation of pro-inflammatory cytokines and their role in blastocyst activation and implantation is poorly known. The present study is aimed at analysing the expression and hormonal modulation of two pro-inflammatory cytokines [interleukin-1alpha (IL-1alpha) and IL-6] in mouse blastocysts during implantation. METHOD OF STUDY: Blastocyst-uterine interactions are inhibited by progesterone during implantation and subsequent treatment with oestrogen triggers events that allow implantation to begin. Using this delayed implantation mouse model, dormant and activated blastocysts were recovered from mice treated with progesterone alone and progesterone plus oestrogen therapy, respectively. Expression of IL-1alpha and IL-6 messenger RNA (mRNA) was analysed in normal, dormant and activated blastocysts by in situ hybridization using specific labelled sense and antisense RNA probes, and the protein expression of the same was analysed by immunocytochemistry. RESULTS: In situ hybridization revealed IL-1alpha and IL-6 mRNA localization in normal, dormant and activated blastocysts and a differential expression was observed in relation to the exposure to progesterone and oestrogen. There was less expression in the dormant blastocysts as compared with the normal and activated ones, and the pattern was similar for both cytokines. Immunocytochemistry also revealed a similar pattern of protein expression to that of the mRNA expression for both the cytokines. CONCLUSIONS: Using a delayed implantation model, we show that mouse blastocysts express both IL-1alpha and IL-6 mRNA as well as their respective proteins. Both mRNA and the protein levels of IL-1alpha and IL-6 seem to be hormonally modulated in mouse blastocysts during implantation.     

The prostaglandin E1 analogue, misoprostol, regulates inflammatory cytokines and immune functions in vitro like the natural prostaglandins E1, E2 and E3.

We examined whether some immune functions related to the action and production of cytokines could be regulated by the natural prostaglandins E (PGE) and the PGE1 (ester) analogue, Misoprostol. PGE1,2,3 and Misoprostol inhibited: (1) the mitogenic activity of interleukin-1 (IL-1) for mouse thymocytes; (2) spreading of mouse macrophages on glass; (3) tumour necrosis factor (TNF) (alpha and beta) production by human peripheral blood mononuclear cells and rat macrophages; (4) IL-1 production by rat and mouse peritoneal macrophages; and (5) interferon-gamma (IFN-gamma) production by human peripheral blood mononuclear cells. These PGE had little effect on IL-1 production by human monocytes. By contrast, they all enhanced IL-6 production by rat and mouse macrophages and human monocytes. These effects were noted at concentrations below 500 nM (even as low as 10 nM). The relative potency of the prostanoids tested for both inhibitory and stimulatory effects was PGE1 = PGE2 = or greater than PGE3 greater than Misoprostol greater than PGA2 much greater than PGF1-alpha = PGF2-alpha = PGD2 (no effect). There is strong evidence that PGE1,2,3 and Misoprostol bind to the same receptor(s) and trigger the second messenger, cAMP, since dibutyryl cAMP (a lipophilic analogue of cAMP) had the same effects as the PGE. These PGE also induced elevated intracellular cAMP levels in and competed with [3H]PGE2 for binding to human and rat cells with the same relative potencies as described above.     

Noxious stimulus-induced increase in spinal prostaglandin E2 is noradrenergic terminal-dependent

Prostaglandins (PGs) were measured in perfusate from the lumbar intrathecal (IT) space of pentobarbital anaesthetized rats. The level of PGE2, but not of PGF2 alpha or 6-keto PGF1 alpha, was increased by immersion of a hindpaw in water at a noxious temperature (50 degrees C). No increase in PGE2 was produced by non-noxious thermal stimulation (35 degrees C water). The noxious stimulus-evoked increase in PGE2, and increases in PGE2 during norepinephrine infusion (10 micrograms/ml), were significantly decreased in rats pretreated with intrathecal 6-hydroxydopamine. These data suggest that noxious stimuli induce an increase in the production of spinal PGE2 and that this production derives from, or requires the presence of noradrenergic terminals in the spinal cord.     

Urinary leukotriene E4 and 9α, 11β-prostaglandin F2 concentrations in mild, moderate and severe asthma, and in healthy subjects

BACKGROUND: Airway inflammation in asthma is associated with cysteinyl leukotriene and prostaglandin D(2) production. Measurement of urinary metabolites of these eicosanoids may be useful for monitoring asthma patients. However, the influence of asthma phenotype and severity on basal urinary excretion of these metabolites is unknown. OBJECTIVE: To compare urinary leukotriene (LT)E(4) and 9 alpha, 11 beta-prostaglandin (PG)F(2) concentrations in large groups of mild, moderate and severe asthmatic patients and healthy control subjects. METHODS: Asthma severity, treatment and aspirin sensitivity were assessed by questionnaire in 168 asthmatic patients. Basal LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations were measured in urine samples from these patients and from 175 control subjects using enzyme immunoassays. RESULTS: Urinary LTE(4) was correlated with 9 alpha, 11 beta-PGF(2) in both control subjects and asthmatic patients (P<0.002). Median LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations in patients with severe asthma were significantly reduced compared with mild asthmatic patients (P<0.05 and <0.001, respectively). Urinary 9 alpha, 11 beta-PGF(2), but not LTE(4) was lower in asthmatic patients using inhaled corticosteroids (P<0.02). Multiple regression analysis indicated that urinary 9 alpha, 11 beta-PGF(2) concentration was negatively correlated with asthma severity (P=0.003) and also with % predicted FEV(1) (forced expiratory volume in 1 s) (P=0.005). CONCLUSIONS: Baseline urinary LTE(4) and 9 alpha, 11 beta-PGF(2) concentrations are of limited value in discriminating between patients with different severities of asthma. Reduced urinary LTE(4) and 9 alpha, 11 beta-PGF(2) in patients with severe asthma suggest that direct or indirect effects of high-dose corticosteroid therapy combined with other factors associated with severe asthma may influence eicosanoid production. However, the negative association of urinary 9 alpha, 11 beta-PGF(2) with lung function suggests an adverse effect of chronic PGD(2) production on lung function in asthma, irrespective of severity.     

Allergen-induced airway inflammation and bronchial responsiveness in interleukin-5 receptor α chain-deficient mice

OBJECTIVE: The role of IL-5 receptor alpha chain (IL-5Ralpha) in the onset of bronchial hyperresponsiveness (BHR) to acetylcholine was investigated by testing IL-5Ralpha knockout (IL-5Ralpha KO) mice. METHODS: Mice were immunized with antigen at intervals of 12 days. Starting 10 days after the secondary immunization, mice were exposed to antigen three times every fourth day. Twenty-four hours after the last antigen challenge, bronchial responsiveness to acetylcholine was measured and bronchoalveolar lavage was carried out. RESULTS: Twenty-four hours after the last antigen inhalation, total and differential cells counts of bronchoalveolar lavage revealed a significant increase in eosinophils and lymphocytes in ovalbumin-exposed wild-type mice. In IL-5Ralpha KO mice, there was little increase of eosinophils in bronchoalveolar lavage fluid (BALF). The production of IL-5 in BALF increased in both mice after repeated antigen challenge, and there was no significant difference between wild-type and IL-5Ralpha KO mice. Similar to the BAL study, histological sections of lung tissue from ovalbumin-exposed wild-type mice exhibited airway eosinophilic inflammation, which was attenuated by the deficiency of IL-5Ralpha chain. There was no significant difference in serum antigen-specific IgE levels between wild-type and IL-5Ralpha KO mice after immunization nor antigen inhalation. Repeated antigen provocation caused BHR to acetylcholine in wild-type mice. In contrast, no BHR was observed in IL-5Ralpha KO mice after repeated inhalation of antigen. CONCLUSION: These findings indicate that IL-5Ralpha plays an important role in the development of antigen-induced airway eosinophilia and BHR in mice.     

Interleukin-1 up-regulates transcription of its own receptor in a human fibroblast cell line TIG-1: role of endogenous PGE2 and cAMP.

The regulation of interleukin-1 receptor (IL-1R) mRNA expression by IL-1 in a human lung fibroblast cell line (TIG-1) was investigated. After 2 h of stimulation with human recombinant IL-1 alpha or IL-1 beta, the levels of T cell/fibroblast-type IL-1R mRNA increased, and the elevation was sustained for at least 72 h. IL-1 also stimulated synthesis of prostaglandin E2 (PGE2) and secondary cAMP accumulation. Exogenously added PGE2 increased the levels of both IL-1R mRNA and intracellular cAMP. Forskolin, cholera toxin and 8-Bromo adenosine (8-Br-cAMP) all increased IL-1R mRNA levels. Indomethacin blocked IL-1 stimulation of IL-1R mRNA expression, PGE2 production and cAMP. 125I-labeled IL-1 alpha-binding studies showed that this cell line expresses 2.6 x 10(4) IL-1R per cell with a Kd of 5.1 x 10(-10) M. After treatment of the cells with IL-1, the level of IL-1R increased over that of control cells. PGE2 also increased IL-1R without alteration in its affinity. Cross-linking experiments indicate that this cell line expresses the 80-kDa receptor molecule before and after treatment with PGE2; the molecular mass corresponds to the T cell/fibroblast type I IL-1R. These results indicate that IL-1 does not directly stimulate expression of IL-1R mRNA or cell surface IL-1R, but only indirectly by stimulation of endogenous PGE2.     

脂多糖对白细胞介素27的调节作用及其与环氧化酶2及前列腺素E2之间的相关性研究

目的 探讨脂多糖(LPS)在THP-1细胞对白细胞介素27(IL-27)的调节作用,阐明IL-27与环氧化酶2(COX-2)及前列腺素E2(PGE2)之间的关系.方法 采用不同浓度的LPS和IL-27刺激THP-1细胞,并在不同时间采用酶联免疫吸附试验(ELISA)检测细胞上清中IL-27和PGE2的含量,同时采用反转录PCR和Western blot检测COX-2的mRNA和蛋白表达的变化.结果 LPS在THP-1细胞能够诱导IL-27的产生,并呈时间和剂量依赖关系;IL-27能够在mRNA和蛋白水平诱导COX-2的表达,同时诱导PGE2的产生,其诱导作用呈时间和剂量依赖效应.结论 LPS能够在细胞水平刺激IL-27的分泌,同时IL-27能够诱导COX-2的表达和PGE2的产生.