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Background and purpose: Obesity is associated with an elevated risk of severe respiratory infections and inflammatory lung diseases. The objectives were to investigate (i) the production of adiponectin by human lung explants, (ii) the expression of the adiponectin receptors AdipoR1 and AdipoR2 by human lung macrophages (LMs), and (iii) the impact of recombinant human adiponectin and a small-molecule APN receptor agonist (AdipoRon) on LMs activation. Experimental approach: Human parenchyma explants and LMs were isolated from patients operated for carcinoma. The LMs were cultured with recombinant adiponectin or AdipoRon and stimulated with LPS (10 ng.mL-1), poly(I:C) (10 µg.mL-1) or interleukin(IL)-4 (10 ng.mL-1) for 24 h. Cytokines or adiponectin, released by explants or LMs, were measured using ELISAs. The mRNA levels of AdipoR1 and AdipoR2 were determined using real-time quantitative PCR. AdipoRs expression was also assessed with confocal microscopy. Key results: Adiponectin was released by lung explants at a level negatively correlated with the donor’s body mass index. AdipoR1 and AdipoR2 were both expressed in LMs. Adiponectin (3-30 µg.mL-1) and AdipoRon (25-50 μM) markedly inhibited the LPS- and poly(I:C)-induced release of Tumor Necrosis Factor-alpha, IL-6 and chemokines (CCL3, CCL4, CCL5, CXCL1, CXCL8, CXCL10) and the IL-4-induced release of chemokines (CCL13, CCL17, CCL22) in a concentration-dependent manner. Recombinant adiponectin produced in mammalian cells (lacking low molecular weight isoforms) had no effects on LMs. Conclusions and implications: The low-molecular-weight isoforms of adiponectin and AdipoRon have an anti-inflammatory activity in the lung environment. Targeting adiponectin receptors may constitute a new means of controlling airways inflammation.

Background: The Toll-like receptor (TLR) family is involved in the recognition of and response to microbial infections. These receptors are expressed in leukocytes. TLR stimulation induces the production of proinflammatory cytokines and chemokines. Given that human lung macrophages (LMs) constitute the first line of defense against inhaled pathogens, the objective of this study was to investigate the expression and function of TLR subtypes in this cell population. Methods: Human primary LMs were obtained from patients undergoing surgical resection. The RNA and protein expression levels of TLRs, chemokines, and cytokines were assessed after incubation with subtype-selective agonists. Results: In human LMs, the TLR expression level varied from one subtype to another. Stimulation with subtype-selective agonists induced an intense, concentration- and time-dependent increase in the production of chemokines and cytokines. TLR4 stimulation induced the strongest effect, whereas TLR9 stimulation induced a much weaker response. Conclusions: The stimulation of TLRs in human LMs induces intense cytokine and chemokine production, a characteristic of the proinflammatory M1 macrophage phenotype.

Background and Purpose 15-Lipoxygenase (15-LOX) activity is associated with inflammation and immune regulation. The objectives of the present study were to investigate the expression of 15-LOX-1 and 15-LOX-2 and evaluate the enzymes' roles in the polarization of human lung macrophages (LMs) in response to LPS and Th2 cytokines (IL-4/-13). Experimental Approach LMs were isolated from patients undergoing surgery for carcinoma. The cells were cultured with a 15-LOX inhibitor (PD146176 or ML351), a COX inhibitor (indomethacin), a 5-LOX inhibitor (MK886) or vehicle and then stimulated with LPS (10 ng·mL−1), IL-4 (10 ng·mL−1) or IL-13 (50 ng·mL−1) for 24 h. Levels of ALOX15 (15-LOX-1) and ALOX15B (15-LOX-2) transcripts were determined by real-time quantitative PCR. Immunoassays were used to measure levels of LPS-induced cytokines (TNF-α, CCL2, CCL3, CCL4, CXCL1, CXCL8 and CXCL10) and Th2 cytokine-induced chemokines (CCL13, CCL18 and CCL22) in the culture supernatant. Key Results Stimulation of LMs with LPS was associated with increased expression of ALOX15B, whereas stimulation with IL-4/IL-13 induced the expression of ALOX15. PD146176 and ML351 (10 μM) reduced the release of the chemokines induced by LPS and Th2 cytokines. The effects of these 15-LOX inhibitors were maintained in the presence of indomethacin and MK886. Furthermore, indomethacin revealed the inhibitory effect of PD146176 on TNF-α release. Conclusions and Implications Inhibition of the 15-LOX pathways is involved in the down-regulation of the in vitro production of chemokines in LMs. Our results suggest that the 15-LOX pathways have a role in the pathogenesis of inflammatory lung disorders and may thus constitute a potential drug target.

International audience; Background: β2-adrenoceptor agonists have been shown to reduce the lipopolysaccharide (LPS)-induced cytokine release by human monocyte-derived macrophages (MDMs). We compare the expression of β2-adrenoceptors and the inhibitory effect of formoterol and salmeterol on the LPS-induced release of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and a range of chemokines (CCL2, 3, 4, and IL-8) by human lung macrophages (LMs) and MDMs. Methods: LMs were isolated from patients undergoing resection and MDMs were obtained from blood monocytes in the presence of GM-CSF. LMs and MDMs were incubated in the absence or presence of formoterol or salmeterol prior to stimulation with LPS. The effects of formoterol were also assessed in the presence of the phosphodiesterase inhibitor roflumilast. Results: LPS-induced cytokine production was higher in LMs than in MDMs. Salmeterol and formoterol exerted an inhibitory effect on the LPS-induced production of TNF-α, IL-6, CCL2, CCL3, and CCL4 in MDMs. In contrast, the β2-adrenoceptor agonists were devoid of any effect on LMs - even in the presence of roflumilast. The expression of β2-adrenergic receptors was detected on Western blots in MDMs but not in LMs. Conclusions: Concentrations of β2-adrenoceptor agonists that cause relaxation of the human bronchus can inhibit cytokine production by LPS-stimulated MDMs but not by LMs. © 2017 The Author(s).

Introduction The epithelial-derived cytokine, thymic stromal lymphopoietin (TSLP), has been identified as an important cytokine in allergic inflammation. Various studies demonstrated elevate levels and expression of TSLP in airways of asthmatic. Environmental factors such as toll-like receptor ligands, viruses, microbes, allergen sources, diesel exhaust and cigarette smoke trigger TSLP production by epithelial cells. It has been described that TSLP amplifies the differentiation of peritoneal macrophages and bone marrow derived macrophages in M2-type in mice. Our aims were to investigate the role of TSLP in the M1/M2 polarization of human lung macrophages (LM). Material and methods Lung macrophages were isolated from tissues obtained after surgical resection for cancer. Macrophages were treated with LPS (10 ng/mL) or IL-4 (10 ng/mL) in presence or not of TSLP (10–30 ng/mL) for 24 h or 48 h. Production of cytokines of the M1-type (TNF-α, CCL-2, CXCL-8 and CXCL-1) and the M2-type (CCL-13, CCL-17, CCL-18 and CCL-22) was determined by ELISA and cytokine expression by RT-qPCR. Results Exposure to TSLP did not alter the production of TNF-α, CXCL-8 and CXCL-1 either in unstimulated LM or in LPS-stimulated LM. However, CCL-2 production was increased by TSLP at 20 ng/mL in unstimulated LM. In addition, TSLP (10 ng/mL but not 30 ng/mL) increased M2-type cytokine production (CCL-13 and CCL-17, but did not CCL-18 and CCL-22). TSLP also increased IL4-induced CCL-17 and CCL-22. Expression of CCL-17 and CCL-13 was also increased by TSLP in unstimulated LM, and expression of CCL-17 and CCL-22 was increased in IL-4-stimulantes LM. Conclusion Our results show that TSLP can activate unstimulated LM and modulate the IL-4-induced polarization of LM in the M2 subtype.

Background Bitter-taste receptors (TAS2Rs) have recently been involved in the relaxation of mouse and guinea pig airways, and increased expression of TAS2Rs was shown in blood leucocytes from asthmatic children. We sought to identify and characterize the TAS2Rs expressed in isolated human bronchi and the subtypes involved in relaxation. Methods Human bronchi were isolated from resected lungs and TAS2R transcripts were assessed with RT-qPCR. Relaxation to TAS2R agonists was tested in organ bath in the presence or absence of pharmacological modulators of the signalling pathways involved in bronchial relaxation. Results We detected the expression of TAS2R transcripts in human bronchi. The non-selective agonists chloroquine, quinine, caffeine, strychnine and diphenidol produced a bronchial relaxation as effective and potent as theophylline but much less potent than formoterol and isoproterenol. Denatonium, saccharin and colchicine did not produce relaxation. Receptor expression analysis together with the use of selective agonists suggest a predominant role for TAS2R5, 10 and 14 in bitter taste agonist-induced relaxation. The mechanism of relaxation was independent of the signalling pathways modulated by conventional bronchodilators and may be partly explained by the inhibition of phosphatidylinositol-3-kinases. Conclusions The TAS2Rs may constitute a new therapeutic target in chronic obstructive lung diseases such as asthma.