IL-1beta induces eotaxin gene transcription in A549 airway epithelial cells through NF-kappaB

Association between genetic polymorphisms of NOD1, Interleukin-1B, and cagA strain with low-grade duodenal eosinophilia in Helicobacter pylori-related dyspepsia

BACKGROUND

Functional dyspepsia (FD) is a multifactorial disorder. Helicobacter pylori (H. pylori)-related dyspepsia (HpD) may be considered a separate entity. Duodenal eosinophilia is a potential pathogenic mechanism in FD. However, the impact of duodenal eosinophilia and host genetic polymorphism of innate and pro-inflammatory cascade, nucleotide-binding oligomerization domain 1 (NOD-1), and interleukin-1 beta (IL-1β) in HpD was not explored.

AIM

To evaluate the association of NOD1-796G>A and IL-1B-511C>T gene variants and low-grade duodenal eosinophilia in HpD.

METHODS

A multicenter cross-sectional study was conducted. A total of 253 patients who met Rome-IV criteria were selected before upper endoscopy and 98 patients were included after unremarkable upper endoscopy and positive H. pylori in gastric biopsies were assessed. Clinical parameters, H. pylori cagA and duodenal histology, were evaluated.

RESULTS

Sixty-four (65%) patients had epigastric pain syndrome (EPS), 24 (25%) postprandial distress syndrome (PDS), and 10 (10%) EPS/PDS overlap. FD subtypes were not associated with NOD1-796G>A and IL-1B-511C>T gene variants. Low-grade duodenal eosinophilia was significantly increased in NOD1-796 GG versus single A-allele, but not in IL-1B-511 single T-allele or CC-allele. This association is dependent of cagA infection, since harboring cagA strain was significantly associated with low-grade duodenal eosinophilia with isolated variants NOD1-796 GG and IL-1B-511 single T-allele, but not without cagA. When we performed combined polymorphism analysis with NOD1-796 GG/IL-1B-511 single T-allele, a synergistic effect on low-grade duodenal eosinophilia was found between these two loci irrespective of cagA strain status in HpD.

CONCLUSION

Our findings suggest that low-grade duodenal eosinophilia is significantly associated with NOD1-796 GG allele specially in cagA strain and with allelic combination NOD1-796 GG/IL-1B-511 single T-allele independent of cagA strain infection in HpD patients.

IL-35 Suppresses Lipopolysaccharide-Induced Airway Eosinophilia in EBI3-Deficient Mice

EBI3 functions as the subunit of immune-regulatory cytokines, such as IL-27 and IL-35, by pairing with p28 and p35, respectively. We treated wild-type and EBI3-deficient mice with intratracheal administration of LPS and obtained bronchoalveolar lavage fluid (BALF) 24 h later. Although neutrophils were the predominant cells in BALF from both groups of mice, eosinophils were highly enriched and there was increased production of eosinophil-attracting chemokines CCL11 and CCL24 in BALF of EBI3-deficient mice. The bronchial epithelial cells and alveolar macrophages were the major producers of CCL11 and CCL24. Because no such increases in eosinophils were seen in BALF of p28/IL-27-deficient mice or WSX-1/IL-27Rα subunit-deficient mice upon intratracheal stimulation with LPS, we considered that the lack of IL-35 was responsible for the enhanced airway eosinophilia in EBI3-deficient mice. In vitro, IL-35 potently suppressed production of CCL11 and CCL24 by human lung epithelial cell lines treated with TNF-α and IL-1β. IL-35 also suppressed phosphorylation of STAT1 and STAT3 and induced suppressor of cytokine signaling 3. In vivo, rIL-35 dramatically reduced LPS-induced airway eosinophilia in EBI3-deficient mice, with concomitant reduction of CCL11 and CCL24, whereas neutralization of IL-35 significantly increased airway eosinophils in LPS-treated wild-type mice. Collectively, our results suggest that IL-35 negatively regulates airway eosinophilia, at least in part by reducing the production of CCL11 and CCL24.

CARMA3 Is Critical for the Initiation of Allergic Airway Inflammation

Innate immune responses to allergens by airway epithelial cells (AECs) help initiate and propagate the adaptive immune response associated with allergic airway inflammation in asthma. Activation of the transcription factor NF-κB in AECs by allergens or secondary mediators via G protein-coupled receptors (GPCRs) is an important component of this multifaceted inflammatory cascade. Members of the caspase recruitment domain family of proteins display tissue-specific expression and help mediate NF-κB activity in response to numerous stimuli. We have previously shown that caspase recruitment domain-containing membrane-associated guanylate kinase protein (CARMA)3 is specifically expressed in AECs and mediates NF-κB activation in these cells in response to stimulation with the GPCR agonist lysophosphatidic acid. In this study, we demonstrate that reduced levels of CARMA3 in normal human bronchial epithelial cells decreases the production of proasthmatic mediators in response to a panel of asthma-relevant GPCR ligands such as lysophosphatidic acid, adenosine triphosphate, and allergens that activate GPCRs such as Alternaria alternata and house dust mite. We then show that genetically modified mice with CARMA3-deficient AECs have reduced airway eosinophilia and proinflammatory cytokine production in a murine model of allergic airway inflammation. Additionally, we demonstrate that these mice have impaired dendritic cell maturation in the lung and that dendritic cells from mice with CARMA3-deficient AECs have impaired Ag processing. In conclusion, we show that AEC CARMA3 helps mediate allergic airway inflammation, and that CARMA3 is a critical signaling molecule bridging the innate and adaptive immune responses in the lung.

Decidualized human endometrial stromal cells are sensors of hormone withdrawal in the menstrual inflammatory cascade

Menstruation is a complex process dependent on premenstrual release of inflammatory mediators and proteolytic enzymes from endometrial cells. Endometrial leukocytes are traditionally considered to be the major source of the inflammatory factors. However, evidence is emerging to suggest a role for decidualized endometrial stromal cells in the premenstrual inflammatory cascade. We sought to determine if withdrawal of hormone support (estrogen and progesterone) from decidualized endometrial stromal cells, in a model mimicking the precise timing leading to menstruation, activated inflammatory signaling pathways and downstream release of inflammatory mediators. Human endometrial stromal cells decidualized gradually over 12 days of estradiol and progestin treatment as evidenced by an increase in prolactin secretion. Withdrawal of hormone support from decidualized stromal cells resulted in a decrease in cytoplasmic IkappaB and a progressive increase in nuclear accumulation of NF-kappaB, as demonstrated by Western immunoblot and immunocytochemical analyses. Concomitant with nuclear translocation of NF-kappaB, hormone withdrawal led to production of a host of inflammatory mediators by the decidualized stromal cells, including IFN-alpha, IL-6, CCL11, GM-CSF, CCL2, IL1-RA, CXCL10, CXCL8, IL-12, IL-15, VEGF, and CCL5. Elevation of inflammatory mediators was not observed, however, upon hormone withdrawal in cells treated with the NF-kappaB inhibitor BAY 11-7085. Decidualized stromal cells are likely highly sensitive sensors of changing hormone levels. This provides a mechanism by which decidualized stromal cells may recruit inflammatory leukocytes into the premenstrual endometrium and contribute to the intense inflammation underlying this unique physiological process.

IL-36α exerts pro-inflammatory effects in the lungs of mice

Interleukin (IL-) 36 cytokines (previously designated as novel IL-1 family member cytokines; IL-1F5- IL-1F10) constitute a novel cluster of cytokines structurally and functionally similar to members of the IL-1 cytokine cluster. The effects of IL-36 cytokines in inflammatory lung disorders remains poorly understood. The current study sought to investigate the effects of IL-36α (IL-1F6) and test the hypothesis that IL-36α acts as a pro-inflammatory cytokine in the lung in vivo. Intratracheal instillation of recombinant mouse IL-36α induced neutrophil influx in the lungs of wild-type C57BL/6 mice and IL-1αβ(-/-) mice in vivo. IL-36α induced neutrophil influx was also associated with increased mRNA expression of neutrophil-specific chemokines CXCL1 and CXCL2 in the lungs of C57BL/6 and IL-1αβ(-/-) mice in vivo. In addition, intratracheal instillation of IL-36α enhanced mRNA expression of its receptor IL-36R in the lungs of C57BL/6 as well as IL-1αβ(-/-) mice in vivo. Furthermore, in vitro incubation of CD11c(+) cells with IL-36α resulted in the generation of neutrophil-specific chemokines CXCL1, CXCL2 as well as TNFα. IL-36α increased the expression of the co-stimulatory molecule CD40 and enhanced the ability of CD11c(+) cells to induce CD4(+) T cell proliferation in vitro. Furthermore, stimulation with IL-36α activated NF-κB in a mouse macrophage cell line. These results demonstrate that IL-36α acts as a pro-inflammatory cytokine in the lung without the contribution of IL-1α and IL-1β. The current study describes the pro-inflammatory effects of IL-36α in the lung, demonstrates the functional redundancy of IL-36α with other agonist cytokines in the IL-1 and IL-36 cytokine cluster, and suggests that therapeutic targeting of IL-36 cytokines could be beneficial in inflammatory lung diseases.

Vitamin E forms inhibit IL-13/STAT6-induced eotaxin-3 secretion by up-regulation of PAR4, an endogenous inhibitor of atypical PKC in human lung epithelial cells

Eotaxin-3 (CCL-26), a potent chemokine for eosinophil recruitment and contributing significantly to the pathogenesis of asthma, is secreted by lung epithelial cells in response to T helper 2 cytokines including interleukin 13 (IL-13). Here we showed that vitamin E forms, but not their metabolites, differentially inhibited IL-13-stimulated generation of eotaxin-3 in human lung epithelial A549 cells. The relative inhibitory potency was γ-tocotrienol (γ-TE) (IC50 ~15 μM)>γ-tocopherol, δ-tocopherol (IC50 ~25-50 μM)>α-tocopherol. Consistent with suppression of eotaxin, γ-TE treatment impaired IL-13-induced phosphorylation of STAT6, the key transcription factor for activation of eotaxin expression, and consequently blocked IL-13-stimulated DNA-binding activity of STAT6. In search of the upstream target of γTE by using inhibitor and siRNA approaches, we discovered that the atypical protein kinase C (aPKC) signaling, instead of classical PKC, p38 MAPK, JNK or ERK, played a critical role in IL-13-stimulated eotaxin generation and STAT6 activation. While showing no obvious effect on aPKC expression or phosphorylation, γ-TE treatment resulted in increased expression of prostate-apoptosis-response 4 (PAR4), an endogenous negative regulator of aPKCs. Importantly, γ-TE treatment led to enhanced formation of aPKC/PAR4 complex that is known to reduce aPKC activity via protein-protein crosstalk. Our study demonstrated that γ-TE inhibited IL-13/STAT6-activated eotaxin secretion via up-regulation of PAR4 expression and enhancement of aPKC-PAR4 complex formation. These results support the notion that specific vitamin E forms may be useful anti-asthmatic agents.

Small molecule modulators of histone acetylation and methylation: a disease perspective

Chromatin modifications have gained immense significance in the past few decades as key regulators of gene expression. The enzymes responsible for these modifications along with the other non-histone proteins, remodeling factors and small RNAs modulate the chromatin dynamicity, which in turn directs the chromatin function. A concerted action of different modifying enzymes catalyzes these modifications, which are read by effector modules and converted to functional outcomes by various protein complexes. Several small molecules in the physiological system such as acetyl CoA, NAD(+), and ATP are actively involved in regulating these functional outcomes. Recent understanding in the field of epigenetics indicate the possibility of the existence of a network, 'the epigenetic language' involving cross talk among different modifications that could regulate cellular processes like transcription, replication and repair. Hence, these modifications are essential for the cellular homeostasis, and any alteration in this balance leads to a pathophysiological condition or disease manifestation. Therefore, it is becoming more evident that modulators of these modifying enzymes could be an attractive therapeutic strategy, popularly referred to as 'Epigenetic therapy.' Although this field is currently monopolized by DNA methylation and histone deacetylase inhibitors, this review highlights the modulators of the other modifications namely histone acetylation, lysine methylation and arginine methylation and argues in favor of their therapeutic potential.

Caffeic acid phenethyl ester suppresses the induction of eotaxin in human lung fibroblast cells

BACKGROUND

Eotaxin, a CC chemokine, plays an important role in inflammation of airway allergic diseases. The authors investigated the activities of caffeic acid phenethyl ester (CAPE), the active component of propolis, in regulating eotaxin production in human lung fibroblast.

MATERIAL AND METHODS

The authors used human lung fibroblasts, CCD-11Lu cells, stimulated with interleukin-13 (IL-13) and tumor necrosis factor-alpha (TNF-alpha), to induce eotaxin secretion. The cells were treated with CAPE of different concentrations and pretreatment duration to check its inhibition in eotaxin production. Enzyme-linked immunosorbent assay (ELISA) was used to measure eotaxin secretion; electrophoretic mobility shift assay (EMSA) to check nuclear factor kappa B (NF-kappaB)-promoter binding; and Western blot to quantitate the cyplasmic inhibitor of NF-kappaB (IkappaB) and nuclear NF-kappaB p65.

RESULTS

CAPE inhibited the production of eotaxin in CCD-11Lu cells stimulated by IL-13 and TNF-alpha combination in a dose- and time-dependent manner. The authors also demonstrated CAPE to be able to inhibit NF-kappaB activation in CCD-11Lu cells.

CONCLUSION

The authors suggest that CAPE is a promising agent in controlling eosinophils influx in human airway.

Interleukin-1 family member 9 stimulates chemokine production and neutrophil influx in mouse lungs

Interleukin-1 (IL-1) is a proinflammatory cytokine that signals through the Type I IL-1 receptor (IL-1RI). Novel IL-1-like cytokines were recently identified. Their functions in lung disease remain unclear. Interleukin-1 family member-9 (IL-1F9) is one such IL-1-like cytokine, expressed in the lungs of humans and mice. IL-1F9 signals through IL-1 receptor-related protein 2 (IL-1Rrp2/IL-1RL2), which is distinct from IL-1RI. We sought to determine if IL-1F9 acts as a proinflammatory cytokine in lung disease. IL-1F9 protein was increased in lung homogenates of house dust mite-challenged A/J mice compared with controls, and expression was seen in airway epithelial cells. The intratracheal administration of recombinant mouse IL-1F9 increased airway hyperresponsiveness and induced neutrophil influx and mucus production, but not eosinophilic infiltration in the lungs of mice. In addition, IL-1α protein levels in bronchoalveolar lavage fluid, chemokines, and chemokine-receptor mRNA expression in the lungs were increased after the instillation of intratracheal IL-1F9. Consistent with these changes, NF-κB transcription factor activity was increased in the lungs of mice challenged with IL-1F9 and in a macrophage cell line treated with IL-1F9. These data suggest that IL-1F9 is upregulated during inflammation, and acts as a proinflammatory cytokine in the lungs.

A new compound, 1H,8H-pyrano[3,4-c]pyran-1,8-dione, suppresses airway epithelial cell inflammatory responses in a murine model of asthma

Clinical and experimental studies have established eosinophilia as a sign of allergic disorders. Activation of eosinophils in the airways is believed to cause epithelial tissue injury, contraction of airway smooth muscle and increased bronchial responsiveness. As part of the search for new antiasthmatic agents produced by medicinal plants, the effects of 270 standardized medicinal plant extracts on cytokine-activated A549 human lung epithelial cells were evaluated. After several rounds of activity-guided screening, the new natural compound, 1H,8H-Pyrano[3,4-c]pyran-1,8-dione (PPY), was isolated from Vitex rotundifolia L. To elucidate the mechanism by which the anti-asthmatic responses of PPY occurred in vitro, lung epithelial cells (A549 cell) were stimulated with TNF-alpha, IL-4 and IL-1beta to induce the expression of chemokines and adhesion molecules involved in eosinophil chemotaxis. PPY treatments reduced the expression of eotaxin, IL-8, IL-16 and VCAM-1 mRNA significantly. Additionally, PPY reduced eotaxin secretion in a dose-dependent manner and significantly inhibited eosinophil migration toward A549 medium. In addition, PPY treatment suppressed the phosphorylation of p65 and ERK1/2, suggesting that it can inhibit the MAPK/NF-KB pathway. To clarify the anti-inflammatory and antiasthmatic effects of PPY in vivo, we examined the influence of PPY on the development of pulmonary eosinophilic inflammation in a murine model of asthma. To accomplish this, mice were sensitized and challenged with ovalbumin (OVA) and then examined for the following typical asthmatic reactions: an increase in the number of eosinophils in BALF; the presence of Th2 cytokines such as IL-4 and IL-5 in the BALF; the presence of allergen-specific IgE in the serum; and a marked influx of inflammatory cells into the lung. Taken together, our results revealed that PPY exerts profound inhibitory effects on the accumulation of eosinophils into the airways while reducing the levels of IL-4, IL-5, and IL-13 in the BALF. Therefore, these results suggest that PPY may be useful as a new therapeutic drug for the treatment of allergic asthma.

Pathway focused protein profiling indicates differential function for IL-1B, -18 and VEGF during initiation and resolution of lung inflammation evoked by carbon nanoparticle exposure in mice

Background

Carbonaceous nanoparticles possess an emerging source of human exposure due to the massive release of combustion products and the ongoing revolution in nanotechnology. Pulmonary inflammation caused by deposited nanoparticles is central for their adverse health effects. Epidemiological studies suggest that individuals with favourable lung physiology are at lower risk for particulate matter associated respiratory diseases probably due to efficient control of inflammation and repair process. Therefore we selected a mouse strain C3H/HeJ (C3) with robust lung physiology and exposed it to moderately toxic carbon nanoparticles (CNP) to study the elicited pulmonary inflammation and its resolution.

Methods

5 μg, 20 μg and 50 μg CNP were intratracheally (i.t.) instilled in C3 mice to identify the optimal dose for subsequent time course studies. Pulmonary inflammation was assessed using histology, bronchoalveolar lavage (BAL) analysis and by a panel of 62 protein markers.

Results

1 day after instillation of CNP, C3 mice exhibited a typical dose response, with the lowest dose (5 μg) representing the 'no effect level' as reflected by polymorphonuclear leucocyte (PMN), and BAL/lung concentrations of pro-inflammatory proteins. Histological analysis and BAL-protein concentration did not reveal any evidence of tissue injury in 20 μg CNP instilled animals. Accordingly time course assessment of the inflammatory response was performed after 3 and 7 days with this dose (20 μg). Compared to day 1, BAL PMN counts were significantly decreased at day 3 and completely returned to normal by day 7. We have identified protein markers related to the acute response and also to the time dependent response in lung and BAL. After complete resolution of PMN influx on day 7, we detected elevated concentrations of 20 markers that included IL1B, IL18, FGF2, EDN1, and VEGF in lung and/or BAL. Biological pathway analysis revealed these factors to be involved in a closely regulated molecular cascade with IL1B/IL18 as upstream and FGF2/EDN1/VEGF as downstream molecules.

Conclusion

Considering the role of VEGF, FGF2 and EDN1 in lung development and morphogenesis together with the lack of any evident tissue damage we suggest a protective/homeostatic machinery to be associated in lungs of stable organisms to counter the CNP challenge as a precautionary measure.

IL-1 receptors mediate persistent, but not acute, airway hyperreactivity to ozone in guinea pigs

Ozone exposure in the lab and environment causes airway hyperreactivity lasting at least 3 days in humans and animals. In guinea pigs 1 day after ozone exposure, airway hyperreactivity is mediated by eosinophils that block neuronal M(2) muscarinic receptor function, thus increasing acetylcholine release from airway parasympathetic nerves. However, mechanisms of ozone-induced airway hyperreactivity change over time, so that depleting eosinophils 3 days after ozone makes airway hyperreactivity worse rather than better. Ozone exposure increases IL-1beta in bone marrow, which may contribute to acute and chronic airway hyperreactivity. To test whether IL-1beta mediates ozone-induced airway hyperreactivity 1 and 3 days after ozone exposure, guinea pigs were pretreated with an IL-1 receptor antagonist (anakinra, 30 mg/kg, intraperitoneally) 30 minutes before exposure to filtered air or to ozone (2 ppm, 4 h). One or three days after exposure, airway reactivity was measured in anesthetized guinea pigs. The IL-1 receptor antagonist prevented ozone-induced airway hyperreactivity 3 days, but not 1 day, after ozone exposure. Ozone-induced airway hyperreactivity was vagally mediated, since bronchoconstriction induced by intravenous acetylcholine was not changed by ozone. The IL-1 receptor antagonist selectively prevented ozone-induced reduction of eosinophils around nerves and prevented ozone-induced deposition of extracellular eosinophil major basic protein in airways. These data demonstrate that IL-1 mediates ozone-induced airway hyperreactivity at 3 days, but not 1 day, after ozone exposure. Furthermore, preventing hyperreactivity was accompanied by decreased eosinophil major basic protein deposition within the lung, suggesting that IL-1 affects eosinophil activation 3 days after ozone exposure.

Role of PKC-delta on substance P-induced chemokine synthesis in pancreatic acinar cells

Interaction of the neuropeptide substance P (SP) with its high-affinity neurokinin-1 receptor (NK1R) plays an important role in the pathophysiology of acute pancreatitis. SP is known to stimulate the production of chemokines monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1 alpha, and MIP-2 in pancreatic acinar cells via the activation of NF-kappaB. However, the signaling mechanisms by which the SP-NK1R interaction induces NF-kappaB activation and chemokine production remain unclear. To that end, in the present study, we investigated the participation of PKC in SP-induced chemokine production in pancreatic acinar cells. In this study, we showed that SP stimulated an early phosphorylation of PKC isoform PKC-delta followed by increased activation of MAPKKK MEKK1 and MAPK ERK and JNK as well as transcription factor NF-kappaB and activator protein-1 driven chemokine production. Depletion of PKC-delta with its inhibitor rottlerin or the specific PKC-delta translocation inhibitor peptide dose dependently decreased SP-induced PKC-delta, MEKK1, ERK, JNK, NF-kappaB, and AP-1 activation. Moreover, rottlerin as well as PKC-delta translocation inhibitor inhibited SP-induced chemokine production in a concentration-dependent manner. We also demonstrated that PKC-delta activation was attenuated by CP96345, a selective NK1R antagonist, thus showing that PKC-delta activation was indeed mediated by SP in pancreatic acinar cells. These results show that PKC-delta is an important proinflammatory signal transducer for SP-NK1R-induced chemokine production in pancreatic acinar cells.

Inhibition effects of Moutan Cortex Radicis on secretion of eotaxin in A549 human epithelial cells and eosinophil migration

Eosinophils have been implicated in a broad range of diseases, most notably allergic conditions (e.g. asthma, rhinitis and atopic dermatitis) and inflammatory diseases. These diseases are characterized by an accumulation of eosinophils in the tissue. Defining the mechanisms that control eosinophil recruitment is fundamental to understanding how these diseases progress and may identify a novel target for drug therapy. Eotaxin is a potent eosinophil-specific chemokine that is released in the respiratory epithelium after allergic stimulation.

AIM OF THE STUDY

In this study, we determined whether Moutan Cortex Radicis (MCR), a plant extract, effects eotaxin secretion from A549 epithelial cells and eosinophil chemotaxis, and then examined the mechanism involved.

MATERIALS AND METHODS

Prior to assaying MCR's effects, A549 cells were stimulated with tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4) and IL-1beta to induce expression of chemokines and adhesion molecules involved in eosinophil chemotaxis. In the presence of MCR, eotaxin, regulated on activation in normal T cells expressed and secreted (RANTES), IL-8, IL-16, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) transcripts were quantitated by real-time RT-PCR.

RESULTS

As a result, 0.01, 1, and 100 microg/ml of MCR treatments reduced eotaxin expression significantly and 0.01, 0.1, 1, 10, and 100 microg/ml of MCR reduced significantly eotaxin secretion. In addition, MCR treatment significantly inhibited eosinophil migration toward A549 medium. And 100 microg/ml of MCR suppressed the activated of nuclear factor (NF)-kappaB.

CONCLUSIONS

These findings indicate that suppressed eotaxin secretion by MCR treatment is due to the inhibition of NF-kappaB activation. Therefore, MCR might be of therapeutic value in treating asthma.

Type I interleukin-1 receptor is required for pulmonary responses to subacute ozone exposure in mice

Interleukin (IL)-1, a proinflammatory cytokine, is expressed in the lung after ozone (O(3)) exposure. IL-1 mediates its effects through the type I IL-1 receptor (IL-1RI), the only signaling receptor for both IL-1alpha and IL-1beta. The purpose of this study was to determine the role of IL-1RI in pulmonary responses to O(3.) To that end, wild-type, C57BL/6 (IL-1RI(+/+)) mice and IL-1RI-deficient (IL-1RI(-/-)) mice were exposed to O(3) either subacutely (0.3 ppm for 72 h) or acutely (2 ppm for 3 h). Subacute O(3) exposure increased bronchoalveolar lavage fluid (BALF) protein, interferon-gamma-inducible protein (IP)-10, soluble tumor necrosis factor receptor 1 (sTNFR1), and neutrophils in IL-1RI(+/+) and IL-1RI(-/-) mice. With the exception of IP-10, all outcome indicators were reduced in IL-1RI(-/-) mice. Furthermore, subacute O(3) exposure increased IL-6 mRNA expression in IL-1RI(+/+), but not IL-1RI(-/-) mice. Acute (2 ppm) O(3) exposure increased BALF protein, IL-6, eotaxin, KC, macrophage inflammatory protein (MIP)-2, IP-10, monocyte chemotactic protein-1, sTNFR1, neutrophils, and epithelial cells in IL-1RI(+/+) and IL-1RI(-/-) mice. For IL-6, eotaxin, MIP-2, and sTNFR1, there were small but significant reductions of these outcome indicators in IL-1RI(-/-) versus IL-1RI(+/+) mice at 6 hours after exposure, but not at other time points, whereas other outcome indicators were unaffected by IL-1RI deficiency. These results suggest that IL-1RI is required for O(3)-induced pulmonary inflammation during subacute O(3) exposure, but plays a more minor role during acute O(3) exposure. In addition, these results suggest that the induction of IL-6 via IL-1RI may be important in mediating the effects of O(3) during subacute exposure.

IL-1 beta stimulates divergent upper and lower airway epithelial cell CCL5 secretion

Direct infection of respiratory epithelium induces chemokine secretion and upregulates cytokine networks, which are central in regulating inflammation. IL-1beta may have a pivotal role in such networks. Differential control of chemokine secretion within specific airway regions, which have distinct roles in immunity, is not well characterized. We investigated IL-1beta-induced CXCL8 and CCL5 secretion from primary normal human bronchial and small airway epithelial cells, and the alveolar cell line A549. CXCL8 was secreted by all cells, but only lower airway cells secreted CCL5. IL-1beta induced nuclear translocation of NF-kappaB (p50, p65 and c-Rel subunits), NF-IL-6 and AP-1, each with distinct kinetics. This was associated with high level CCL5 promoter activation, via transcription factor binding to multiple regions, including NF-kappaB, AP-1 and NF-IL-6 sites. The IL-1-related cytokine IL-18 did not drive or modulate IL-1beta-induced CXCL8 or CCL5 secretion. In summary, IL-1beta, but not IL-18, induces transcription-dependent lower airway epithelial cell-specific CCL5 secretion. Differential chemokine secretion may have profound effects on local leukocyte influx within upper or lower airways exposed to airway infection or environmental stimuli, which might then require different anti-inflammatory strategies.

Adenoviral gene transfer of the NF-kappa B inhibitory protein ABIN-1 decreases allergic airway inflammation in a murine asthma model

Airway inflammation is a characteristic of many lung disorders, including asthma and chronic obstructive pulmonary disease. Using a murine model of allergen-induced asthma, we have demonstrated that adenovirus-mediated delivery of the nuclear factor-kappaB (NF-kappaB) inhibitory protein ABIN-1 to the lung epithelium results in a considerable reduction of allergen-induced eosinophil infiltration into the lungs. This is associated with an ABIN-1-induced decrease in allergen-specific immunoglobulin E levels in serum, as well as a significant reduction of eotaxin, interleukin-4, and interleukin-1beta in bronchoalveolar lavage fluid. These findings not only prove that NF-kappaB plays a critical role in the pathogenesis of allergic inflammation but also illustrate that inhibiting NF-kappaB could have therapeutic value in the treatment of asthma and potentially other chronic inflammatory lung diseases.

Role of prostanoid DP receptor variants in susceptibility to asthma

BACKGROUND

Previous genetic studies have associated the region of the human genome (14q22.1) containing the gene for the prostanoid DP receptor (PTGDR) with asthma. A study of a mouse model suggests that the receptor is required for the expression of the asthma phenotype. Our associations of asthma with functional genetic variants of PTGDR link these observations.

METHODS

We identified and evaluated combinations of genetic variants that influence PTGDR transcription for disease association in case-control studies of 518 white patients with asthma and 175 white controls and 80 black patients with asthma and 45 black controls.

RESULTS

We identified four novel and two previously reported single-nucleotide polymorphisms (SNPs) in PTGDR and its vicinity. These define four common three-SNP haplotypes, which vary in their ability to support transcription of PTGDR and have distinct DNA-binding-protein affinity profiles. Individual PTGDR SNPs were significantly associated with asthma in both populations. Specific PTGDR haplotypes were significantly associated with a diagnosis of asthma in a large case-control study of whites (P=0.002); we confirmed these findings in a second population of blacks (P=0.01). Multivariate analysis of the haplotype combinations (diplotypes) demonstrated that both whites (odds ratio, 0.55; 95 percent confidence interval, 0.38 to 0.80; P=0.002) and blacks (odds ratio, 0.32; 95 percent confidence interval, 0.12 to 0.89; P=0.03) who had at least one copy of the haplotype with a low transcriptional efficiency had a lower risk of asthma than subjects with no copies of the haplotype.

CONCLUSIONS

Our functional and genetic findings identify PTGDR as an asthma-susceptibility gene.

Signaling pathways regulating interleukin-13-stimulated chemokine release from airway smooth muscle

Interleukin (IL)-13 receptor activation on airway smooth muscle cells induces eotaxin release and activates multiple signaling pathways including mitogen-activated protein kinases, and signal transducer and activator of transcription 6 (STAT6). To examine a requirement for STAT6 in mediating IL-13-stimulated eotaxin release we used antisense oligodeoxynucleotides (ODNs) to downregulate endogenous STAT6 protein. STAT6 antisense ODNs were taken up by about 85% of cells. Selective downregulation of STAT6 protein occurred with antisense ODNs, but not with sense or scrambled ODNs. Eotaxin release induced by IL-13 or IL-4 (10 ng/ml) was reduced by 81 +/- 4 and 75 +/- 7%, respectively, in cells transfected with antisense ODNs (p < 0.001), but not with a sense ODN or a scrambled ODN. Eotaxin release induced by IL-1beta was unaffected by STAT6 antisense ODN (p > 0.05). Finally, IL-13- or IL-4-dependent eotaxin release was abolished when inhibitors of both p42/p44 ERK (U0126, 10 microM) and p38 (SB202190, 10 microM) mitogen-activated protein kinase pathways were combined in STAT6 antisense ODN-transfected cells. In contrast, about 25% of the response remained when each inhibitor was examined alone in STAT6 antisense ODN-treated cells. These data support roles for both STAT6- and mitogen-activated protein kinase-dependent pathways in mediating eotaxin release from airway smooth muscle by IL-13 or IL-4.

Paradoxical early glucocorticoid induction of stem cell factor (SCF) expression in inflammatory conditions

1. Stem cell factor (SCF) is a major growth factor for mast cells, promoting their differentiation and chemotaxis. Its expression is regulated by glucocorticoids in inflammatory conditions, showing an early increased protein expression, before the expected anti-inflammatory decrease (Da Silva et al., Br. J. Pharmacol. 2002:135,1634). 2. We here evaluated the early kinetic of SCF expression regulated by interleukin (IL)-1beta, budesonide and the combination of both in human lung fibroblasts in culture. 3. Budesonide potentiated the IL-1beta-enhanced expression of SCF mRNA (+103%) and protein (+98%) very shortly after treatment (at 30 min and 1 h, respectively). A gentle downregulation followed. This potentiating effect of budesonide was related to increased SCF mRNA stability and SCF gene transcription. 4. Deletion of a kappaB-like site that we identified in the first intron of the SCF gene, in a luciferase reporter system, abolished the potentiation by budesonide, as well as the effect of IL-1beta alone, as compared to the wild-type construction activity. 5. All budesonide-induced effects were glucocorticoid-receptor dependent, since they were reproduced by dexamethasone and blocked by RU486. 6. IL-1beta+budesonide did not affect the relative expression of the soluble and membrane-bound forms of SCF. 7. In conclusion, our results clearly show that glucocorticoids act very early to adversely increase the expression of SCF mRNA and protein in the inflammatory conditions created by IL-1beta, and that this effect involves increased mRNA stability and increased gene expression through activation of the NF-kappaB-like responsive element.

Monocyte chemoattractant protein-4 core promoter genetic variants: influence on YY-1 affinity and plasma levels

Monocyte chemoattractant protein-4 (MCP-4) is a CC chemokine implicated in the recruitment of eosinophils, monocytes, and T-lymphocytes in diseases of mucosal inflammation, including asthma. We tested the hypothesis that there is a genetic basis for differences in MCP-4 expression among individuals by evaluating the effects of core promoter variants on MCP-4 expression. We identified two single-nucleotide T-to-C polymorphisms in the MCP-4 core promoter that occur 896 and 887 base pairs preceding the transcription initiation site. The -887 variant alters a consensus binding motif for the transcription factor YY-1. Electrophoretic mobility shift assay demonstrated that YY-1 containing nuclear extracts from tumor necrosis factor-alpha-stimulated peripheral blood mononuclear cells had greater avidity for the wild-type (YY-1 motif intact) sequence than for the variant sequence. Increasing doses of a YY-1 expression vector induced significantly greater reporter activity from MCP-4 core promoter expression constructs of the wild-type compared with the variant sequence in transient transfection experiments. The external validity of these observations was demonstrated by measuring plasma levels of MCP-4 from individuals with the alternative forms of the gene. Individuals bearing haplotypic variants of the MCP-4 core promoter that avidly bind the transcription factor YY-1 had higher plasma levels of MCP-4 than did individuals with variants with lower binding avidity (490, 360, and 360 pg/ml; P < 0.01). Our findings suggest that the MCP-4 core promoter YY-1 binding motif is functional, modulates the transcriptional regulation of the MCP-4 gene, and that part of the variance in the systemic expression of MCP-4 is determined by core promoter genetic variants.

Glucocorticoid inhibition of SP-A gene expression in lung type II cells is mediated via the TTF-1-binding element

Induction of surfactant protein-A (SP-A) gene expression in fetal lung type II cells by cAMP and IL-1 is mediated by increased binding of thyroid transcription factor-1 (TTF-1) and NF-B proteins p50 and p65 to the TTF-1-binding element (TBE) at -183 bp. In type II cell transfections, dexamethasone (Dex) markedly inhibits cAMP-induced expression of rabbit SP-A:human growth hormone (hGH) fusion genes containing as little as 300 bp of the SP-A 5'-flanking sequence. Dex inhibition is blocked by RU-486, suggesting a role of the glucocorticoid receptor (GR). The present study was undertaken to define the mechanisms for GR inhibition of SP-A expression. Cotransfection of primary cultures of type II cells with a GR expression vector abrogated cAMP induction of SP-A promoter activity while, at the same time, causing a 60-fold induction of cotransfected mouse mammary tumor virus (MMTV) promoter. In lung cells transfected with a fusion gene containing three TBEs fused to the basal SP-A promoter, Dex prevented the stimulatory effect of IL-1 on TTF-1 induction of SP-A promoter activity, suggesting that the GR inhibits SP-A promoter activity through the TBE. In gel shift assays using nuclear extracts from human fetal type II cells cultured in the absence or presence of cAMP, Dex markedly reduced binding of nuclear proteins to the TBE and blocked the stimulatory effect of cAMP on TBE-binding activity. Our finding that Dex increased expression of the NF-kappaB inhibitory partner IkappaB-alpha suggests that the decrease in TBE-binding activity may be caused, in part, by GR inhibition of NF-kappaB interaction with this site.

Regulation of beta-adrenergic responses in airway smooth muscle

Decreased responsiveness to beta-adrenergic receptor agonists is a characteristic feature of human asthma. This review summarizes data regarding the impact of chronic beta agonist stimulation, cytokines, prostanoids and other factors on beta-adrenergic responses in human airway smooth muscle, as well as the impact of polymorphisms of the beta(2)-adrenergic receptor on these responses. Effects of beta-agonists on both airway smooth muscle relaxation and gene expression are considered. Understanding the regulation of beta-adrenergic responses in airway smooth muscle cells may prove to be an important step in improving the efficacy of beta-agonists for the treatment of asthma.

Involvement of p38 MAPK, JNK, p42/p44 ERK and NF-kappaB in IL-1beta-induced chemokine release in human airway smooth muscle cells

Asthma is an inflammatory disease, in which eotaxin, MCP-1 and MCP-3 play a crucial role. These chemokines have been shown to be expressed and produced by IL-1beta-stimulated human airway smooth muscle cells (HASMC) in culture. In the present study we were interested to unravel the IL-1beta-induced signal transduction leading to chemokine production. Using Western blot, we observed an activation of p38 MAPK, JNK kinase and p42/p44 ERK when HASMC were stimulated with IL-1beta. We also observed a significant decrease in the expression and the release of eotaxin, MCP-1 and MCP-3 in the presence of SB203580, an inhibitor of p38 MAPK (71 +/- 6%, P < 0.05, n = 8 and 39 +/- 10% P < 0.01, n = 10 respectively), curcumin, an inhibitor of JNK kinase (83 +/- 4.9% and 88 +/- 3.4% respectively, P < 0.01, n = 4). U0126, an inhibitor of p42/p44 ERK, also produced a significant decrease in chemokine production (46.3 +/- 9%, P < 0.01 n = 10 and 67.8 +/- 12%, P < 0.01, n = 12). Pyrrolydine dithiocarbamate, an inhibitor of NF-kappaB was also able to reduce the eotaxin, MCP-1 and MCP-3 expression and production (50 +/- 13%, P < 0.05, n = 10 and 23 +/- 7%, P < 0.05, n = 12). We conclude that p38 MAPK, JNK kinase, ERK and NF-kappaB are involved in the IL-1beta-induced eotaxin, MCP-1, and MCP-3 expression and release in HASMC.

Interleukin-1beta stimulates macrophage inflammatory protein-1alpha and -1beta expression in human neuronal cells (NT2-N)

Chemokines are important mediators in immune responses and inflammatory processes of neuroimmunologic and infectious diseases. Although chemokines are expressed predominantly by cells of the immune system, neurons also express chemokines and chemokine receptors. We report herein that human neuronal cells (NT2-N) produce macrophage inflammatory protein-1alpha and -1beta (MIP-1alpha and MIP-1beta), which could be enhanced by interleukin (IL)-1beta at both mRNA and protein levels. The addition of supernatants from human peripheral blood monocyte-derived macrophage (MDM) cultures induced MIP-1beta mRNA expression in NT2-N cells. Anti-IL-1beta antibody removed most, but not all, of the MDM culture supernatant-induced MIP-1beta mRNA expression in NT2-N cells, suggesting that IL-1beta in the MDM culture supernatants is a major factor in the induction of MIP-1beta expression. Investigation of the mechanism(s) responsible for IL-1beta-induced MIP-1alpha and -1beta expression demonstrated that IL-1beta activated nuclear factor kappa B (NF-kappaB) promoter-directed luciferase activity in NT2-N cells. Caffeic acid phenethyl ester, a potent and specific inhibitor of activation of NF-kappaB, not only blocked IL-1beta-induced activation of the NF-kappaB promoter but also decreased IL-1beta-induced MIP-1alpha and -1beta expression in NT2-N cells. These data suggest that NF-kappaB is at least partially involved in the IL-1beta-mediated action on MIP-1alpha and -1beta in NT2-N cells. IL-1beta-mediated up-regulation of beta-chemokine expression may have important implications in the immunopathogenesis of inflammatory diseases in the CNS.

Oncostatin M regulates eotaxin expression in fibroblasts and eosinophilic inflammation in C57BL/6 mice

Oncostatin M (OSM) is a member of the IL-6/LIF (or gp130) cytokine family, and its potential role in inflammation is supported by a number of activities identified in vitro. In this study, we investigate the action of murine OSM on expression of the CC chemokine eotaxin by fibroblasts in vitro and on mouse lung tissue in vivo. Recombinant murine OSM stimulated eotaxin protein production and mRNA levels in the NIH 3T3 fibroblast cell line. IL-6 could regulate a small induction of eotaxin in NIH 3T3 cells, but other IL-6/LIF cytokines (LIF, cardiotrophin-1 (CT-1)) had no effect. Cell signaling studies showed that murine OSM, LIF, IL-6, and CT-1 stimulated the tyrosine phosphorylation of STAT-3, suggesting STAT-3 activation is not sufficient for eotaxin induction in NIH 3T3 cells. OSM induced ERK-1,2 and p38 mitogen-activated protein kinase phosphorylation in NIH 3T3 cells, and inhibitors of ERK (PD98059) or p38 (SB203580) could partially reduce OSM-induced eotaxin production, suggesting partial dependence on mitogen-activated protein kinase signaling. OSM (but not LIF, IL-6, or CT-1) also induced eotaxin release by mouse lung fibroblast cultures derived from C57BL/6 mice. Overexpression of murine OSM in lungs of C57BL/6 mice using an adenovirus vector encoding murine OSM resulted in a vigorous inflammatory response by day 7 after intranasal administration, including marked extracellular matrix accumulation and eosinophil infiltration. Elevated levels of eotaxin mRNA in whole lung were detected at days 4 and 5. These data strongly support a role of OSM in lung inflammatory responses that involve eosinophil infiltration.

Rapid activation of nuclear factor-kappaB in airway epithelium in a murine model of allergic airway inflammation

Bronchiolar epithelium is postulated to play a critical role in the orchestration of responses to inhaled allergens, and may contribute to the pathogenesis of asthma. Using a murine model of allergic airway inflammation and hyperresponsiveness, we demonstrate in mice sensitized with ovalbumin (OVA) that following a single challenge with nebulized OVA, a rapid and protracted activation of inhibitor of kappa B kinase (IKK) occurred in lung tissue. IKK activation was followed by nuclear localization of nuclear factor (NF)-kappaB within the bronchiolar epithelium and increased luciferase activity in lungs of mice containing a NF-kappaB-dependent reporter gene. Challenge of sensitized mice with OVA also induced mRNA expression of the chemokines, macrophage inflammatory protein-2 (MIP-2) and eotaxin in lung tissue, which corresponded temporally with the observed influx of neutrophils and eosinophils, respectively, into the airspaces. Using laser capture microdissection and quantitative polymerase chain reaction, we demonstrated that MIP-2 and eotaxin were predominantly expressed in bronchiolar epithelium, in contrast to distal regions of the lungs, which expressed lower or undetectable levels of these mRNAs. These studies strengthen the potential importance of the bronchiolar epithelial cell as a source of production of NF-kappaB-dependent mediators that play a role in asthma.

IL-13 and IL-4 cause eotaxin release in human airway smooth muscle cells: a role for ERK

Human airway smooth muscle (HASM) cells express interleukin (IL)-13 and IL-4 receptors and respond to these cytokines with signal transducer and activator of transcription-6 and extracellular signal-regulated kinase (ERK) activation. The purpose of this study was to determine whether IL-13 and/or IL-4 influence eotaxin release in HASM cells and whether the ERK mitogen-activated protein (MAP) kinase pathway is involved in these events. Eotaxin release into HASM cell supernatants was assayed by ELISA, and eotaxin mRNA expression was determined by Northern blot analysis. Pretreatment with either IL-13 or IL-4 resulted in a concentration- and time-dependent release of eotaxin, although IL-4 was more effective. Eotaxin release was approximately twice baseline after treatment with 50 ng/ml IL-13 or IL-4 (P < 0.001). IL-13 and IL-4 also acted synergistically with tumor necrosis factor (TNF)-alpha to induce eotaxin release: TNF-alpha alone (10 ng/ml for 24 h) resulted in an approximately fourfold increase in eotaxin release, whereas TNF-alpha in combination with IL-13 or IL-4 resulted in 10- or 20-fold increases (P < 0.05). Similar results were obtained for eotaxin mRNA expression. Pretreatment with either U-0126 (10 microM) or PD-98059 (30 microM), both inhibitors of MAP/ERK kinase, the enzyme upstream of ERK, inhibited IL-13- or IL-4-induced eotaxin release (P < 0.05). U-0126 also inhibited IL-13, and TNF-alpha induced mRNA expression. Our results indicate that IL-13 and IL-4 cause eotaxin release in HASM cells through a mechanism that, in part, involves ERK activation and suggest that the smooth muscle may be an important source of chemokines leading to eosinophil recruitment in asthma.

Inhibition by glucocorticoids of the interleukin-1beta-enhanced expression of the mast cell growth factor SCF

1. Stem cell factor (SCF) is a major mast cell growth factor that promotes differentiation and chemotaxis of mast cells and inhibits their apoptosis. 2. We evaluated the effect of interleukin (IL)-1beta, a major pro-inflammatory cytokine, on the constitutive expression of SCF and studied the effects of two glucocorticoids, budesonide and dexamethasone, on the IL-1beta-enhanced SCF expression. 3. Human lung fibroblasts in culture were serum-starved for 48 h and treated with IL-1beta, budesonide and/or RU486. SCF cDNA was quantified after total RNA reverse transcription by on-line fluorescent polymerase chain reaction. SCF protein was quantified by ELISA. 4. IL-1beta induced an increase in SCF mRNA (+91% at 2.5 h) and protein production (+32%) by human lung fibroblasts in culture (P<0.001). 5. Budesonide inhibited IL-1beta-induced SCF mRNA expression (-68%) at 2.5 h and even more so at 10 h (-192%) (P<0.001). The expression of SCF protein also decreased by 3.5-fold at 10 h. Results were similar with dexamethasone. The glucocorticoid antagonist RU486 cancelled the effects induced by the glucocorticoids. 6. Increased SCF mRNA levels were associated with increased stability of this mRNA as measured after treatment with actinomycin D (1.9-fold at 2.5 h). Budesonide decreased this IL-1beta-enhanced stability by about 1.5-fold (P<0.001). 7. We conclude that in 'inflammatory' conditions, mimicked in vitro by IL-1beta, glucocorticoid treatment inhibits expression of the mast cell growth factor SCF. The reduced number and activation of mast cells observed in the bronchi of asthmatic patients treated by glucocorticoids may be due in part to this effect.

IL-4 differentially regulates eotaxin and MCP-4 in lung epithelium and circulating mononuclear cells

To investigate the mechanisms of eosinophil recruitment in allergic airway inflammation, we examined the effects of interleukin (IL)-4, a Th2-type cytokine, on eotaxin and monocyte chemoattractant protein-4 (MCP-4) expression in human peripheral blood mononuclear cells (PBMCs; n = 10), in human lower airway mononuclear cells (n = 5), in the human lung epithelial cell lines A549 and BEAS-2B, and in human cultured airway epithelial cells. IL-4 inhibited eotaxin and MCP-4 mRNA expression induced by IL-1 beta and tumor necrosis factor-alpha in PBMCs but did not significantly inhibit expression in epithelial cells. Eotaxin and MCP-4 mRNA expression was not significantly induced by proinflammatory cytokines in lower airway mononuclear cells. IL-1 beta-induced eotaxin and MCP-4 protein production was also inhibited by IL-4 in PBMCs, whereas IL-4 enhanced eotaxin protein production in A549 cells. In contrast, dexamethasone inhibited eotaxin and MCP-4 expression in both PBMCs and epithelial cells. The divergent effects of IL-4 on eotaxin and MCP-4 expression between PBMCs and epithelial cells may create chemokine concentration gradients between the subepithelial layer and the capillary spaces that may promote the recruitment of eosinophils to the airway in Th2-type responses.