Nociceptin reduces the inflammatory immune microenvironment in a conventional murine model of airway hyperresponsiveness.

BACKGROUND: Nociceptin/orphanin FQ (N/OFQ) and its receptor (NOP) are involved in airway hyperresponsiveness (AHR) and inflammation. However, the role of nociceptin at modulating the inflammatory immune microenvironment in asthma is still unclear. OBJECTIVE: To understand the role of N/OFQ in the regulation of a Th2-like environment, we used a conventional murine model of AHR. METHODS: Balb/c and CD1 mice were sensitized to ovalbumin (OVA) and treated with saline solution or N/OFQ, at days 0 and 7. A group of Balb/c mice were killed at 7 and 14 days from the first sensitization for the inflammatory profile evaluation while a group of Balb/c and CD1 mice were aerosol-challenged from day 21 to 23 with OVA and killed 24 h later for functional evaluations. RESULTS: In OVA-sensitized mice, N/OFQ significantly reduced IL-4+ CD4+ T cells in lymph nodes (LN) and IL-13 in the lungs, while it induced IFN-γ increase in the lung. The efflux of dendritic cells (DCs) to the mediastinic LN and into the lung of OVA-sensitized mice was reduced in N/OFQ-treated and sensitized mice. N/OFQ reduced the expression of CD80 on DCs, indicating its ability to modulate the activation of DCs. In a less prone Th2-like environment mice strain, such as CD1 mice, N/OFQ did not modify lung resistances as observed in BALB/c mice. Finally, spectroscopic data showed the N/OFQ was able to interact onto the membrane of DCs obtained from Balb/c rather than CD1 mice, indicating its ability to modulate AHR in a Th2-like environment with a direct activity on DCs. CONCLUSIONS AND CLINICAL RELEVANCE: Our data confirmed the capability of N/OFQ to modulate the immune microenvironment in the lung of Th2-biased, OVA-sensitized Balb/c mice, suggesting N/OFQ-NOP axis as a novel pharmacological tool to modulate the inflammatory immune microenvironment in asthma.

Airways allergic inflammation and L. reuterii treatment in asthmatic children.

Recently, it has been hypothesized that the oral administration of specific live probiotic strains may have therapeutic potential in the treatment of allergic inflammation. The aim of this study was to evaluate the effect of the oral L. reuteri DSM 17938 administration (1X108CFU), in airways allergic inflammation in mild persistent asthmatic children. In this DBPC randomized study we selected 50 children (6-14 years old), affected by mild persistent asthma (GINA step 2) and allergic to HDM. At the run-in period (T-2), the children were submitted to medical examination, prick tests for the main respiratory allergens, spirometry and children asthma control test (C-ACT). We selected only the children with well controlled asthma (C-ACT >19 and FEV1> 80%). After two weeks (T0) the children were allocated into two groups, the FeNO was measured and the breath condensate was collected. Group A children were treated with the placebo (5 drops per day) and Group B children with L. reuteri (108CFU =5 drops per day) for 60 days. After the treatment period (T1), all patients were evaluated by medical examination, C-ACT, spirometry, FeNO measurement and exaled breath condensate analysis. The FeNO values showed a significant reduction (p=0,045) in L. reuteri group but not in the placebo group at the end of the treatment (T1). Furthermore, the cytokines exam showed an increase in IL-10 levels (p less than 0.05) and a significant reduction in IL-2 levels (p less than 0.05) only in L. reuteri group at T1. No significant differences in FEV1 values and C-ACT score were found in both groups. In conclusion, these data showed that L. reuteri (108 CFU) was effective in reducing bronchial inflammation in asthmatic children. No significant effect was found on FEV1 values and C-ACT score, probably because we selected children with well controlled asthma.

Similar programmed death ligand 1 (PD-L1) expression profile in patients with mild COPD and lung cancer.

Programmed Death Ligand 1 (PD-L1) is crucial in regulating the immunological tolerance in non-small cell lung cancer (NSCLC). Alveolar macrophage (AM)-derived PD-L1 binds to its receptor, PD-1, on surveilling lymphocytes, leading to lymphocyte exhaustion. Increased PD-L1 expression is associated with cigarette smoke (CS)-exposure. However, the PD-L1 role in CS-associated lung diseases associated with NSCLC, such as chronic obstructive pulmonary disease (COPD), is still unclear. In two different cohorts of ever smokers with COPD or NSCLC, and ever and never smoker controls, we evaluated PD-L1 expression: (1) via cutting-edge digital spatial proteomic and transcriptomic profiling (Geomx) of formalin-fixed paraffin-embedded (FFPE) lung tissue sections (n = 19); and (2) via triple immunofluorescence staining of bronchoalveolar lavage (BAL) AMs (n = 83). PD-L1 mRNA expression was also quantified in BAL AMs exposed to CS extract. PD-L1 expression was increased in the bronchiolar wall, parenchyma, and vascular wall from mild-moderate (GOLD 1-2) COPD patients compared to severe-very severe (GOLD 3-4) COPD patients and controls. Within all the COPD patients, PD-L1 protein expression was associated with upregulation of genes involved in tumor progression and downregulation of oncosuppressive genes, and strongly directly correlated with the FEV1% predicted, indicating higher PD-L1 expression in the milder vs. more severe COPD stages. In bronchioles, PD-L1 levels were strongly directly correlated with the number of functionally active AMs. In BAL, we confirmed that AMs from patients with both GOLD 1-2 COPD and NSCLC had the highest and similar, PD-L1 expression levels versus all the other groups, independently from active cigarette smoking. Intriguingly, AMs from patients with more severe COPD had reduced AM PD-L1 expression compared to patients with mild COPD. Acute CS extract stimulation increased PD-L1 mRNA expression only in never-and not in ever-smoker AMs. Lungs from patients with mild COPD and NSCLC are characterized by a similar strong PD-L1 expression signature in bronchioles and functionally active AMs compared to patients with severe COPD and controls. Active smoking does not affect PD-L1 levels. These observations represent a new resource in understanding the innate immune mechanisms underlying the link between COPD and lung cancer onset and progression and pave the way to future studies focused on the mechanisms by which CS promotes tumorigenesis and COPD.

Gas exchange and breathing pattern in women with postmenopausal bone fragility.

BACKGROUND: Little is known about the relationship between bone fragility and respiratory function. We hypothesized that women with osteoporosis or osteopenia, without cardio-pulmonary disease, have perturbations in the pattern of breathing and gas exchange. METHODS: In 44 women with bone fragility (BF, T score: < -1), and 20 anthropomorphically-matched control women (T score > -1) we compared pulmonary function tests, central respiratory drive (mouth occlusion pressure or P 0.1), pattern of breathing using optoelectronic plethysmograph and arterial blood gases at rest. RESULTS: Static pulmonary function was similar in BF subjects and controls. However, the arterial blood gas measurements differed significantly. The arterial pH was significantly higher in BF subjects than in controls (P < 0.001). The partial pressure of carbon dioxide (PaCO2) and oxygen (PaO2) in arterial blood were significantly lower in BF subjects than controls (P < 0.001 and P = 0.009, respectively). The BF subjects had a shorter inspiratory fraction compared with controls (P = 0.036). Moreover, T-scores were significantly inversely correlated with the alveolar-arterial gradient of oxygen (r = -0.5; P = 0.0003) and the arterial pH (r = -0.4; P = 0.002), and positively correlated with arterial PaO2 (r = 0.3; P = 0.01) and PaCO2 (r = 0.4; P = 0.002) among all subjects. CONCLUSION: In the absence of known cardio-pulmonary disease, BF is associated with statistically significant perturbations in gas exchange and alterations in the pattern of breathing including shortening of the inspiratory time.

S1P-induced airway smooth muscle hyperresponsiveness and lung inflammation in vivo: molecular and cellular mechanisms.

BACKGROUND AND PURPOSE: Sphingosine-1-phosphate (S1P) has been shown to be involved in the asthmatic disease as well in preclinical mouse experimental models of this disease. The aim of this study was to understand the mechanism(s) underlying S1P effects on the lung. EXPERIMENTAL APPROACH: BALB/c, mast cell-deficient and Nude mice were injected with S1P (s.c.) on days 0 and 7. Functional, molecular and cellular studies were performed. KEY RESULTS: S1P administration to BALB/c mice increased airway smooth muscle reactivity, mucus production, PGD2 , IgE, IL-4 and IL-13 release. These features were associated to a higher recruitment of mast cells to the lung. Mast cell-deficient Kit (W) (-sh/) (W) (-sh) mice injected with S1P did not display airway smooth muscle hyper-reactivity. However, lung inflammation and IgE production were still present. Treatment in vivo with the anti-CD23 antibody B3B4, which blocks IgE production, inhibited both S1P-induced airway smooth muscle reactivity in vitro and lung inflammation. S1P administration to Nude mice did not elicit airway smooth muscle hyper-reactivity and lung inflammation. Naïve (untreated) mice subjected to the adoptive transfer of CD4+ T-cells harvested from S1P-treated mice presented all the features elicited by S1P in the lung. CONCLUSIONS AND IMPLICATIONS: S1P triggers a cascade of events that sequentially involves T-cells, IgE and mast cells reproducing several asthma-like features. This model may represent a useful tool for defining the role of S1P in the mechanism of action of currently-used drugs as well as in the development of new therapeutic approaches for asthma-like diseases.

Characterization of adenosine receptors involved in adenosine-induced bronchoconstriction in allergic rabbits.

1. Recent work has suggested that adenosine may be involved in asthma via the activation of A1 receptors. However, the role of the recently cloned A3 receptor in airways is largely unknown. In the present study, we have investigated the role of the A3 receptor in adenosine-induced bronchoconstriction in allergic rabbits. 2. Aerosol challenge of antigen (Ag) immunized rabbits with the adenosine precursor, adenosine 5'-monophosphate (AMP), resulted in a dose-dependent fall in dynamic compliance (Cdyn). The maximum fall in Cdyn in these rabbits was significantly greater than that in litter matched, sham immunized animals (P < 0.05). However, there was no significant difference in the maximum increase in airways resistance (Rt) between Ag and sham immunized rabbits (P > 0.05). 3. Aerosol challenge of Ag immunized rabbits with cyclopentyl-adenosine (CPA) (A1-receptor agonist) elicited a dose-dependent fall in Cdyn in Ag immunized rabbits and the maximum fall in Cdyn in these rabbits was significantly greater than that observed in sham immunized rabbits (P < 0.05). Similarly, CPA induced dose-dependent increases in R1 in Ag immunized rabbits whereas sham immunized rabbits failed to respond to CPA within the same dose range. The maximum increase in RL in Ag immunized rabbits was significantly greater than that of sham immunized rabbits (P < 0.05). 4. Aerosol challenge of either Ag or sham immunized rabbits with the A3 agonist aminophenylethyladenosine (APNEA) did not elicit dose-dependent changes in either RL or Cdyn. Moreover, there was no significant difference in the maximum response, measured by either parameter, between the two animal groups (P > 0.05). 5. These data provide further evidence for a role of the A1 receptor in the airways, but do not support a role for the A3 receptor in adenosine-induced bronchoconstriction in the allergic rabbit.

Endothelin-1 increases cholinergic nerve-mediated contraction of human bronchi via tachykinin synthesis induction.

1. In some asthmatics, muscarinic receptor antagonists are effective in limiting bronchoconstrictor response, suggesting an abnormal cholinergic drive in these subjects. There is a growing body of evidences indicating that cholinergic neurotransmission is also enhanced by endothelin-1 (ET-1) in rabbit bronchi, mouse trachea and in human isolated airway preparations. 2. We investigated the role of secondary mediators in ET-1 induced potentiation of cholinergic nerve-mediated contraction in human bronchi, in particular the possible role of neuropeptides in this phenomenon. 3. Bronchial tissues after endothelin treatment were exposed to a standard electrical field stimulation (EFS) (30% of EFS 30 Hz)-induced contraction. In addition, in some experiments, preparations were treated with a tachykinin NK(2) receptor antagonist and subsequently exposed to the same protocol. HPLC and RIA were performed on organ bath fluid samples. Moreover, the human bronchi were used for the beta-PPT (preprotachykinin) mRNA extraction and semiquantitative reverse transcription polymerase chain reaction (RT - PCR), prior to and 30-40 min following ET-1 challenge. 4. The selective tachykinin NK(2) receptor antagonist, SR48968, was effective to reduce ET-1 potentiation of EFS mediated contraction. HPLC or RIA showed significant increased quantities of NKA in organ bath effluents after EFS stimulation in bronchi pretreated with ET-1. Finally, beta-PPT mRNA level after stimulation of bronchi with ET-1 was increased about 2 fold respect to control untreated bronchi. 5. In conclusion, this study demonstrated that, at least in part, the ET-1 potentiation of cholinergic nerve-mediated contraction is mediated by tachykinin release, suggesting that in addition to nerves, several type of cells, such as airway smooth muscle cell, may participate to neuropeptide production.

Endothelin-1 affects capsaicin-evoked release of neuropeptides from rat vas deferens.

Capsaicin-sensitive neurones release a number of neuropeptides, such as substance P, neurokinin A, somatostatin and calcitonin gene-related peptide (CGRP), which exert a number of effects on smooth muscle tissues. Endothelin-1 was thought to potentiate the capsaicin-evoked release of neuropeptides from sensory neurones of the rat. We have investigated the neuromodulatory effects of endothelin-1 on capsaicin-induced release of neurotransmitters from rat vas deferens. Capsaicin and human alpha calcitonin gene-related peptide (human alphaCGRP) reduced the rat vas deferens twitch responses induced by electrical field stimulation. Human beta calcitonin gene-related peptide-(8-37) [human betaCGRP-(8-37)] (1 microM), a selective alphaCGRP receptor antagonist, antagonized the inhibitory effects of both drugs. Endothelin-1 concentration dependently evoked an increase in basal tone of the musculature and potentiated the amplitude of the electrically stimulated responses, blocking inhibitory effects of capsaicin but not of human alphaCGRP. Moreover, endothelin-1 did not markedly change the inhibitory effects of papaverine (0.1-100 microM) or isoprenaline (1 nM-100 microM) on responses to electrical field stimulation. FR 139317 [(N,N-hexamethylene) carbamoyl-Leu-D-Trp(N-Me)-D-2-Pya], a selective endothelin ET(A) receptor antagonist, administered 30 min before endothelin-1 restored the capsaicin effects whereas BQ 788 [Dmpc-gamma-MeLeu-D-Trp-(1-methoxycarbonyl)-D-Nle], a selective endothelin ET(B) receptor antagonist, was completely ineffective. The endothelin-1-induced block of the capsaicin effect was resistant to tetrodotoxin (1 microM) and 30-min pre-treatment with MEN 10.627 (cyclo[(Met-Asp-Trp-Phe-Dap-Leu) cyclo (2beta-5beta)]), a selective tachykinin NK2 receptor antagonist, did not abolish the endothelin-1 effect on the inhibitory response to capsaicin. These results suggest that endothelin-1 selectively inhibits the capsaicin-induced release of neurotransmitters from rat vas deferens and these effects are mediated via endothelin ET(A) receptors but not by tachykinin release.

Endothelin-1 and bronchial hyperresponsiveness in the rabbit.

Endothelins (ETs) are a family of peptide mediators that have a number of biological properties, including the ability to act as potent bronchoconstrictors of isolated human airways. Moreover, elevated concentrations of ET-1 in the bronchoalveolar lavage fluid from patients with symptomatic asthma have also been detected. We investigated the possible contribution of ET-1 in the development of bronchial hyperresponsiveness and the role of inflammatory cell accumulation in rabbit lungs. Our data show that ET-1 challenge to rabbits does not modify basal lung function but results in an increased airway responsiveness to inhaled histamine. Endothelin-treated rabbits were 3-fold (P<0.01) more responsive to inhaled histamine when compared with vehicle-treated rabbits. This hyperresponsiveness was not associated with an alteration in either total or differential inflammatory cell numbers as assessed by bronchoalveolar lavage (BAL). Pre-treatment with capsaicin (80 mg/kg s.c.) did not alter basal lung function or basal responsiveness to inhaled histamine. While capsaicin had no significant effect on the acute bronchoconstriction induced by endothelin-1, this dose was sufficient to significantly inhibit the increase in airway responsiveness to inhaled histamine, achieved 24 h following endothelin-1 challenge. These results indicate that ET-1 may play a role in the development of bronchial hyperresponsiveness to inhaled histamine and that the maintenance of this state is unrelated to a detectable alteration in cellular infiltration within the airway lumen, but probably via the involvement of capsaicin-sensitive nerves.

Endothelin-1 induced bronchial hyperresponsiveness in the rabbit: an ET(A) receptor-mediated phenomenon.

Endothelin-1 (ET-1) is a potent and efficacious spasmogen of airway smooth muscle. Recent observations suggest that an increased intrapulmonary production of ET-1 may occur in asthma. Our previous study showed that endothelin-1 induced bronchial hyperresponsiveness to inhaled histamine in the rabbit. The aim of this study was to investigate whether the ET(A) and ET(B) receptors mediate the bronchial hyperresponsiveness induced by endothelin-1 in the rabbit. Our data showed that bronchial hyperresponsiveness induced by ET-1 was significantly inhibited (P<0.01) by the ET(A) receptor-selective antagonist, FR 139317 (from 2.5 to 10 mg kg(-1)). Moreover, bosentan (from 2.5 mg kg(-1) to 10 mg kg(-1)), an ET(A)/ET(B) receptor antagonist, also inhibited the bronchial hyperresponsiveness achieved 24 h following endothelin-1 challenge (P<0.01), but with no difference from FR 139317. The ET(B) receptor agonist, sarafotoxin S6c (from 25 microg to 2.5 mg kg(-1)) did not modify airway responsiveness to inhaled histamine in the rabbit. These results indicate that bronchial hyperresponsiveness induced by ET-1 may be mediated by ET(A) receptor activation.

Nebivolol and airway responsiveness in the rabbit.

Beta-adrenergic receptor antagonists are currently used as first-line therapy in the treatment of hypertension and angina pectoris, but are contraindicated or used with caution in patients with bronchospastic syndromes. In this study we evaluated in vivo the effects of nebivolol on airway responsiveness compared to atenolol, pindolol, and propranolol. In New Zealand white rabbits total lung resistance (R(L)) and dynamic compliance (Cdyn) were calculated. In acute protocol, the animals were intravenously injected with the beta-blockers at different doses while in the chronic protocol, animals were daily injected for 30 days. Furthermore, the changes induced by beta-blockers (higher doses) in R(L) and Cdyn after a treatment with salbutamol were calculated. In acute treatment, airway responsiveness to histamine was not modified by nebivolol at any dosage, but increased significantly following the exposure to the higher doses of the other beta-blockers. In chronic treatment, the thirty-day exposure to nebivolol, did not modify the airway responsiveness to histamine, whereas the other beta-blockers significantly increased airway responsiveness. Moreover, nebivolol affected the salbutamol-induced relaxation less markedly than other beta-blockers do. These data demonstrate that nebivolol respect the other beta-blockers used in this study, does not significantly affect the airway responsiveness, therefore it could be used in patients with both cardiovascular and bronchial diseases more safely than other beta-blockers drugs.

Nitric oxide regulatory role in sensitized guinea pig trachea.

Nitric oxide (NO) has been cited to play an important regulatory role in airway function. Moreover, the NO synthase expression in models of inflammation is documented. The aim of this study was to investigate, in vitro, the NO modulation of cholinergic responses in sham-sensitized and ovalbumin-sensitized guinea pig trachea by using L-arginine (L-ARG), a precursor of NO synthesis, and L-Ng-nitro-arginine-methyl-ester (L-NAME), an inhibitor of NO synthase. Our results showed that NO's ability to modulate cholinergic responses in ovalbumin-sensitized guinea pig trachea is lost. Indeed L-ARG and L-NAME modify acetylcholine sensitivity in sham-sensitized guinea pig but not in ovalbumin-sensitized guinea pig.

Effects of in vitro 5-HT1 receptor activation in guinea pig trachea.

5-hydroxytryptamine (5-HT) has been reported to show some effects in respiratory tissues by activation of different subtype receptors. It has been demonstrated that 5-HT2 receptor activation causes in vivo and in vitro airways contraction and enhances effects of cholinergic nerve-mediated responses, whereas 5-HT1 receptor activation seems to be related to a relaxant effect. Moreover, in isolated guinea pig ascendens colon preparations 5-HT1 activation causes relaxation by involvement of nitric oxide (NO). The aim of this study was to investigate the effects of 5-HT1 receptor activation in guinea pig trachea as well as NO probable role in this activation. In tissues pretreated with both ketanserin (10 microM), an antagonist of 5-HT2 receptors, and ondansetron (10 microM), an antagonist of 5-HT3 receptors, 5-HT (from 10 nM to 10 mM) relaxed guinea pig trachea precontracted with acetylcholine (ACh, 100 microM). Carboxamidotryptamine (5-CT, from 10 nM to 10 mM), an agonist of 5-HT1 receptors, as well relaxed guinea pig trachea precontracted with ACh (100 microM). A pretreatment with NAN-190 (from 10 nM to 100 microM), a 5-HT1A selective antagonist, reduced the 5-HT and 5-CT relaxant effects but only at very high concentrations. Finally, a pretreatment with L-nitro-arginine-methyl-ester (L-NAME, 1 mM), an inhibitor of NO-synthase, and L-arginine (L-ARG, 1 mM), a precursor of NO synthesis, did not modify 5-HT and 5-CT responses in guinea pig trachea. In conclusion, this study suggests a 5-HT relaxant activity in guinea pig trachea via a 5-HT1 receptor activation without any NO pathway involvement. However, further investigations are needed to clarify which 5-HT1 receptor subtype is involved in 5-HT relaxant effect.

Functional role of nitric oxide in guinea pig tracheal epithelium.

Nitric oxide (NO) may play an important regulatory role in airway function. We have, thus, investigated in vitro whether epithelium derived NO may modulate cholinergic neurotransmission, via release of NO in guinea pig trachea, by using L-arginine (L-ARG), a precursor of NO synthesis, and L-N(G)-nitro-arginine-methyl-ester (L-NAME), an inhibitor of NO synthase. Results show that L-ARG and L-NAME modify acetylcholine sensitivity in epithelium-intact smooth muscle preparations, suggesting a probable NO synthesis by tracheal guinea pig epithelium.

Role of tachykinins in the bronchoconstriction induced by HCl intraesophageal instillation in the rabbit.

Gastroesophageal acid reflux (GER) is a common disorder associated with the exacerbation of asthma. In this study we investigated the effects on the airways of intraoesophageal HCl instillation in the rabbit and the role of tachykinins in these effects. In anaesthetized New Zealand rabbits bronchopulmonary functions [total lung resistance (R(L)) and dynamic compliance (C(dyn))] were calculated before and after HCl intraoesophageal instillation. Infusion of HCl induced a significant bronchoconstriction (P < 0.05) in the terms of R(L) and C(dyn) changes, that were increased by phosphoramidon pre-treatment and reduced by capsaicin pre-treatment. Moreover, a pre-treatment with SR 48968, a tachykinin NK2 receptor antagonist, or SR 140333, a NK1 receptor antagonist, significantly inhibited the bronchoconstriction induced by intraoesophageal HCl infusion in terms of R(L) and C(dyn)changes. Finally, the HCl induced bronchoconstriction was unaffected by SR 142801, a tachykinin NK3 receptor antagonist. In conclusion these results suggest that bronchoconstriction induced by intraoesophageal HCl infusion is mainly dependent on the release of tachykinins and that both NK1 and NK2 tachykinin receptors are involved.

Possible functional modulation by acetylcholine of nitric oxide on guinea pig isolated trachea.

The aim of this study was to evaluate whether acetylcholine induces NO release. We determined the responses on the cholinergic component of the response to electrical field stimulation (EFS) the effects of L-nitro-arginine-methyl-ester (L-NAME; 1 mM), an inhibitor of NO synthase, of L-Arginine (L-ARG; 1 mM), a precursor of NO synthesis, and methoctramine (0.01-0.1-1 microM), an antagonist of M2 receptors, alone or associated with L-NAME. The experiments were performed on guinea pig isolated intact- or denuded-epithelium tracheal rings contracted in a frequency-dependent manner to EFS. At the maximum frequency tested (30 Hz), the contractile response elicited was 60.36 +/- 0.61% of acetylcholine (100 microM) contraction, while the maximal relaxant effect induced by EFS was -28.40 +/- 0.61% in epithelium intact preparations. A pretreatment with L-NAME significantly (P<0.05) increased the contraction (76.08 +/- 1.39%) and reduced the relaxation elicited by EFS. L-NAME effect on both EFS induced responses were statistically (P<0.05) reversed by the association L-NAME + L-ARG. Methoctramine (1 microM) enhanced contractile (P<0.05) (79.20 +/- 2.21%), as well as relaxant responses (-38.73 +/- 0.99%) elicited by EFS in guinea pig epithelium-intact tracheal rings; in a separate series of experiments, performed on guinea pig epithelium-intact rings, L-NAME increased the contractile responses to methoctramine (82.6 +/- 2.31), but reduced the relaxant ones (26.38 +/- 1.29). In contrast, at the maximum frequency tested, it increased only the contractile response, but not modify the relaxant one, in epithelium denuded rings. In conclusion, the present data showed that the release of acetylcholine from postganglionic cholinergic nerves plays an important role on NO formation and this effect may be modulate by epithelium.

Elucidation of the molecular mechanism and the efficacy in vivo of a novel 1,4-benzoquinone that inhibits 5-lipoxygenase.

BACKGROUND AND PURPOSE: 1,4-Benzoquinones are well-known inhibitors of 5-lipoxygenase (5-LOX, the key enzyme in leukotriene biosynthesis), but the molecular mechanisms of 5-LOX inhibition are not completely understood. Here we investigated the molecular mode of action and the pharmacological profile of the novel 1,4-benzoquinone derivative 3-((decahydronaphthalen-6-yl)methyl)-2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (RF-Id) in vitro and its effectiveness in vivo. EXPERIMENTAL APPROACH: Mechanistic investigations in cell-free assays using 5-LOX and other enzymes associated with eicosanoid biosynthesis were conducted, along with cell-based studies in human leukocytes and whole blood. Molecular docking of RF-Id into the 5-LOX structure was performed to illustrate molecular interference with 5-LOX. The effectiveness of RF-Id in vivo was also evaluated in two murine models of inflammation. KEY RESULTS: RF-Id consistently suppressed 5-LOX product synthesis in human leukocytes and human whole blood. RF-Id also blocked COX-2 activity but did not significantly inhibit COX-1, microsomal PGE2 synthase-1, cytosolic PLA2 or 12- and 15-LOX. Although RF-Id lacked radical scavenging activity, reducing conditions facilitated its inhibitory effect on 5-LOX whereas cell stress impaired its efficacy. The reduced hydroquinone form of RF-Id (RED-RF-Id) was a more potent inhibitor of 5-LOX as it had more bidirectional hydrogen bonds within the 5-LOX substrate binding site. Finally, RF-Id had marked anti-inflammatory effects in mice in vivo. CONCLUSIONS AND IMPLICATIONS: RF-Id represents a novel anti-inflammatory 1,4-benzoquinone that potently suppresses LT biosynthesis by direct inhibition of 5-LOX with effectiveness in vivo. Mechanistically, RF-Id inhibits 5-LOX in a non-redox manner by forming discrete molecular interactions within the active site of 5-LOX.

Interleukin-6 receptor superantagonist Sant7 inhibits TGF-beta-induced proliferation of human lung fibroblasts.

OBJECTIVES: Both interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta) are crucially involved in fibrotic events that characterize interstitial lung diseases (ILD). Therefore, the aim of this study was to investigate in primary cultures of normal and fibrotic human lung fibroblasts (HLF), exposed to either IL-6 or TGF-beta1, the effects on phosphorylation of mitogen-activated protein kinases (MAPK) and cell growth of IL-6 signalling inhibition, performed by the IL-6 receptor superantagonist Sant7. MATERIALS AND METHODS: MAPK phosphorylation was detected by Western blotting, HLF viability and proliferation were evaluated using the trypan blue staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, respectively. RESULTS: Sant7, at a concentration of 1 microg/mL, was capable of significantly inhibiting HLF proliferation and MAPK phosphorylation induced by cell exposure to IL-6 (100 ng/mL) or TGF-beta1 (10 ng/mL), whose actions were more evident in fibrotic cells. CONCLUSIONS: These findings suggest that, in HLFs derived from patients with ILDs, the proliferative mechanisms activated by TGF-beta1 are at least in part mediated by an increased release of IL-6, leading to phosphorylation-dependent MAPK activation. Such preliminary findings may thus open new therapeutic perspectives for fibrogenic ILDs, based on inhibition of signal transduction pathways stimulated by the IL-6 receptor.

Activation of protease-activated receptor-2 reduces airways inflammation in experimental allergic asthma.

BACKGROUND: Proteinase-activated receptors (PAR)-2 are members of the family of G-protein-coupled receptors activated by proteases. These receptors are widely expressed in several tissues and in virtually all cells involved in rhinitis and asthma. In particular, proteinases activating PAR-2 may affect airway functions and play a role in human diseases. OBJECTIVE: Assessment of the role of PAR-2 in bronchoconstriction, airway responsiveness and immune response after allergic challenge, in rabbits sensitized to Par j 1, the major allergen of Parietaria judaica pollen. METHODS: Evaluation of antigen challenge in rabbits treated with PAR-2-activating peptide (PAR-2AP) (SLIGRL) or the scrambled peptide LSIGRL or vehicle immediately before allergen exposure measuring airway responsiveness. Characterization of bronchoalveolar lavage (BAL) following histamine challenge and phenotype analysis of cells by flow cytometry and analysis of cytokine production by quantitative PCR. RESULTS: PAR-2AP pre-treatment, but not the scrambled peptide, was able to significantly inhibit bronchoconstriction, airway hyper-responsiveness and to modulate the immune response induced by allergic challenge in sensitized rabbits. The phenotype analysis of the cells recovered from BAL showed an increase in RLA-DR-positive cells while RTLA-positive cells were unchanged. IFN-gamma and IL-2 production were inhibited, with a concomitant increase in IL-10 of about 10-fold over the control values. CONCLUSIONS: In this experimental model, PAR-2 modulates bronchoconstriction interfering with antigen challenge-induced immune response in rabbits sensitized and challenged to Par j 1.