Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: The aryl hydrocarbon receptor (AhR) has gradually emerged as a regulator of inflammation in the lung and other tissues. AhR may interact with the p65-subunit of the nuclear factor (NF)-κB transcription factors, but reported outcomes of AhR/NF-κB-interactions are conflicting. Some studies suggest that AhR possess pro-inflammatory activities while others suggest that AhR may be anti-inflammatory. The present study explored the impact of AhR and its binding partner AhR nuclear translocator (Arnt) on p65-activation and two differentially regulated chemokines, CXCL8 (IL-8) and CCL5 (RANTES), in human bronchial epithelial cells (BEAS-2B). RESULTS: Cells were exposed to CXCL8- and CCL5-inducing chemicals, 1-nitropyrene (1-NP) and 1-aminopyrene (1-AP) respectively, or the synthetic double-stranded RNA analogue, polyinosinic-polycytidylic acid (Poly I:C) which induced both chemokines. Only CXCL8, and not CCL5, appeared to be p65-dependent. Yet, constitutively active unligated AhR suppressed both CXCL8 and CCL5, as shown by siRNA knock-down and the AhR antagonist α-naphthoflavone. Moreover, AhR suppressed activation of p65 by TNF-α and Poly I:C as assessed by luciferase-assay and p65-phosphorylation at serine 536, without affecting basal p65-activity. In contrast, Arnt suppressed only CXCL8, but did not prevent the p65-activation directly. However, Arnt suppressed expression of the NF-κB-subunit RelB which is under transcriptional regulation by p65. Furthermore, AhR-ligands alone at high concentrations induced a moderate CXCL8-response, without affecting CCL5, but suppressed both CXCL8 and CCL5-responses by Poly I:C. CONCLUSION: AhR and Arnt may differentially and independently regulate chemokine-responses induced by both inhaled pollutants and pulmonary infections. Constitutively active, unligated AhR suppressed the activation of p65, while Arnt may possibly interfere with the action of activated p65. Moreover, ligand-activated AhR suppressed CXCL8 and CCL5 responses by other agents, but AhR ligands alone induced CXCL8 responses when given at sufficiently high concentrations, thus underscoring the duality of AhR in regulation of inflammation. We propose that AhR-signaling may be a weak activator of p65-signaling that suppresses p65-activity induced by strong activators of NF-κB, but that its anti-inflammatory properties also are due to interference with additional pathways.
Cell communication and signaling: CCS

hal-01063555
https://hal.archives-ouvertes.fr/hal-01063555
DOI : 10.1186/s12964-014-0048-8

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The objective of this study is to assess the association of clinical manifestations of systemic sclerosis (SSc) with the absolute count of circulating blood monocyte subpopulations according to their membrane expression of CD16. Forty-eight consecutive patients fulfilling the 2013 ACR/EULAR classification criteria for SSc were included in this cross-sectional study. CD16+ monocyte absolute count was defined by flow cytometry and confronted to the clinical characteristics of SSc patients. Twenty-three healthy donors (HD) were randomly selected for comparison. SSc patients had an increased number of total circulating blood monocytes compared to HD (p < 0.001). The CD16- subpopulation absolute count was increased in SSc patients compared to HD (p < 0.001) but was similar in limited SSc (lSSc) and diffuse SSc (dSSc). On the contrary, the CD16+ population absolute count was increased in dSSc compared to both HD and lSSc patients (dSSc 0.071 Giga/L (+/- 0.034) vs HD 0.039 Giga/L (+/- 0.030), p < 0.01, and dSSc 0.071 Giga/L (+/- 0.034) vs lSSc 0.048 Giga/L (+/- 0.024), p < 0.05). The CD16+ monocyte subpopulation absolute count was significantly correlated with the severity of skin fibrosis evaluated by the modified Rodnan skin score (p < 0.001). The CD16+ monocyte subpopulation was also associated with pulmonary fibrosis (p < 0.05), with the severity of the restrictive ventilatory defect evaluated by total lung capacity (p < 0.05) and with the pulmonary function impairment reflected by diffusing capacity of the lungs for carbon monoxyde measures (p < 0.01). These results suggest that CD16+ monocytes are associated with the main fibrotic manifestations of SSc and their role in the pathogenesis of fibrosis in this autoimmune disorder should therefore be further considered.
ISSN: 0770-3198

hal-01560150
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560150
DOI : 10.1007/s10067-017-3597-6
PUBMED : 28293753

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Monocytes/macrophages (MΦ), considered as plastic cells, can differentiate into either a pro-inflammatory (M1) subtype, also known as a classically activated subtype, or an anti-inflammatory alternatively activated subtype (M2) according to their microenvironment. Phenotypic markers of mouse polarized MΦ have been extensively studied, whereas their human counterparts remain less characterized. The main goal of this study was therefore to carefully characterize phenotypic and genomic markers of primary human MΦ generated from M-CSF-treated blood monocytes and polarized towards M1 or M2 subtype upon the action of lipopolysaccharide and interferon-γ (for M1) or interleukin (IL)-4 (for M2). Membrane expression of the markers CD80 and CD200R was found to be specific of human M1 and M2 polarized MΦ, respectively, whereas, by contrast, mannose receptor (CD206) expression did not discriminate between M1 and M2. mRNA expression analysis further identified six markers of M1 polarization (IL-12p35, CXCL10, CXCL11, CCL5, CCR7 and IDO1), five markers of M2 polarization (TGF-β, CCL14, CCL22, SR-B1 and PPARγ) and transcription factors involved in MΦ polarization. Ability of human M-CSF-generated MΦ to polarize toward M1 or M2 subtype was also associated with enhanced secretion of TNFα, IL-1β, IL-12p40, CXCL10 and IL-10 (for M1) or CCL22 (for M2). Moreover, the comparison of the expression of M1 markers in M-CSF- and GM-CSF-MΦ polarized towards M1 subtype has revealed similarities. In conclusion, we demonstrated that human M-CSF MΦ can polarize toward a M1 type after IFNγ/LPS stimulation. Moreover, the M1 and M2 markers of human polarized MΦ identified in the present study may be useful to better identify human MΦ subtypes, particularly at the tissue level, in order to better understand their respective roles in the development of pathologies.
ISSN: 0008-8749

inserm-00823273
http://www.hal.inserm.fr/inserm-00823273
DOI : 10.1016/j.cellimm.2013.01.010
PUBMED : 23454681

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: The aryl hydrocarbon receptor (AhR) has gradually emerged as a regulator of inflammation in the lung and other tissues. AhR may interact with the p65-subunit of the nuclear factor (NF)-κB transcription factors, but reported outcomes of AhR/NF-κB-interactions are conflicting. Some studies suggest that AhR possess pro-inflammatory activities while others suggest that AhR may be anti-inflammatory. The present study explored the impact of AhR and its binding partner AhR nuclear translocator (Arnt) on p65-activation and two differentially regulated chemokines, CXCL8 (IL-8) and CCL5 (RANTES), in human bronchial epithelial cells (BEAS-2B). RESULTS: Cells were exposed to CXCL8- and CCL5-inducing chemicals, 1-nitropyrene (1-NP) and 1-aminopyrene (1-AP) respectively, or the synthetic double-stranded RNA analogue, polyinosinic-polycytidylic acid (Poly I:C) which induced both chemokines. Only CXCL8, and not CCL5, appeared to be p65-dependent. Yet, constitutively active unligated AhR suppressed both CXCL8 and CCL5, as shown by siRNA knock-down and the AhR antagonist α-naphthoflavone. Moreover, AhR suppressed activation of p65 by TNF-α and Poly I:C as assessed by luciferase-assay and p65-phosphorylation at serine 536, without affecting basal p65-activity. In contrast, Arnt suppressed only CXCL8, but did not prevent the p65-activation directly. However, Arnt suppressed expression of the NF-κB-subunit RelB which is under transcriptional regulation by p65. Furthermore, AhR-ligands alone at high concentrations induced a moderate CXCL8-response, without affecting CCL5, but suppressed both CXCL8 and CCL5-responses by Poly I:C. CONCLUSION: AhR and Arnt may differentially and independently regulate chemokine-responses induced by both inhaled pollutants and pulmonary infections. Constitutively active, unligated AhR suppressed the activation of p65, while Arnt may possibly interfere with the action of activated p65. Moreover, ligand-activated AhR suppressed CXCL8 and CCL5 responses by other agents, but AhR ligands alone induced CXCL8 responses when given at sufficiently high concentrations, thus underscoring the duality of AhR in regulation of inflammation. We propose that AhR-signaling may be a weak activator of p65-signaling that suppresses p65-activity induced by strong activators of NF-κB, but that its anti-inflammatory properties also are due to interference with additional pathways.
ISSN: 1478-811X

inserm-01085082
http://www.hal.inserm.fr/inserm-01085082
http://www.hal.inserm.fr/inserm-01085082/document
http://www.hal.inserm.fr/inserm-01085082/file/s12964-014-0048-8.pdf
PUBMED : 25201625

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Lung diseases are aggravated by exposure to diesel exhaust particles (DEPs) found in air pollution. Macrophages are thought to play a crucial role in lung immune response to these pollutants, even if the mechanisms involved remain incompletely characterized. In the present study, we demonstrated that classically and alternative human macrophages (MΦ) exhibited increased secretion of PDGF-B in response to DEP extract (DEPe). This occurred via aryl hydrocarbon receptor (AhR)-activation because DEPe-induced PDGF-B overexpression was abrogated after AhR expression knock-down by RNA interference, in both M1 and M2 polarizing MΦ. In addition, TCDD and benzo(a)pyrene, two potent AhR ligands, also significantly increased mRNA expression of PDGF-B in M1 MΦ, whereas some weak ligands of AhR did not. We next evaluated the impact of conditioned media (CM) from MΦ culture exposed to DEPe or of recombinant PDGF-B onto lung fibroblast proliferation. The tyrosine kinase inhibitor, AG1295, prevents phosphorylations of PDGF-Rβ, AKT and ERK1/2 and the proliferation of MRC5 fibroblasts induced by recombinant PDGF-B and by CM from M1 polarizing MΦ, strongly suggesting that the PDGF-BB secreted by DEPe-exposed MΦ is sufficient to activate the PDGF-Rβ pathway of human lung fibroblasts. In conclusion, we demonstrated that human MΦ, whatever their polarization status, secrete PDGF-B in response to DEPe and that PDGF-B is a target gene of AhR. Therefore, induction of PDGF-B by DEP may participate in the deleterious effects towards human health triggered by such environmental urban contaminants.
ISSN: 0041-008X

hal-01146840
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146840
DOI : 10.1016/j.taap.2015.04.007
PUBMED : 25896968

Éditeur(s) : HAL CCSD
Résumé : International audience
Traffic air pollution is a major health problem and is recognized as an important risk factor for cardiovascular disease. Even so the role of particles-induced adverse health effects is well established, recent studies outlined the contribution of nitrogen dioxide (NO2) in these effects, in particular on the cardiovascular function. The main sources of this pollutant are oxidation catalysts used to reduce emissions of carbon monoxide and non-methane hydrocarbons from the exhaust of diesel engines and also to facilitate filter regeneration. However, the contribution of NO2 compared to other gaseous and particulate pollutants remains unknown. Consequently, the main objective of this study was to analyze the specific contributions of NO2 in the traffic-related air pollution-induced cardiovascular adverse effects. For this, Wistar rats were exposed for 3 weeks (3h/day, 5 days/week) to either a continuous flow of catalyzed diesel exhaust (DE), particle free or whole DE (particles concentration 2mg/m3), either to a continuous flow of NO2 used at a concentration identical to that measured in the exhaust line. The composition of the emission and the NO2 analyses were monitored on-line during the whole experiment. We evaluated cardiac function and biological effects after 16h recovery in clean air. DE or NO2 exposures induced a modest cardiac dysfunction characterized by an increase in left ventricular diameters and a decrease in fractional shortening. In the case of DE, the presence of particles did not worsen the impairment of cardiac function. In parallel to this effect, mitochondrial function was altered as illustrated by the reduction of the oxygen consumption and of the ATP production. Mitochondrial reactive oxygen species was increased only by the NO2 exposure. In conclusion, these results suggest that DE-induced cardiac dysfunction is due to, at least in part, to NO2 present in DE.
Archives of Cardiovascular Diseases Supplements
Toulouse, France

hal-01150495
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150495
DOI : 10.1016/S1878-6480(15)30036-7

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Formaldehyde (FA) is a volatile organic compound (VOC), considered as a major indoor air pollutant and suspected to favor the development of inflammatory lung diseases. The present study was aimed at identifying cytokines/chemokines targeted by FA in human lung cells. This VOC was demonstrated to up-regulate interleukin-11 (IL-11) mRNA and secretion levels in a dose-dependent manner in cultured lung epithelial BEAS-2B cells. It concomitantly induced mRNA expression of transforming growth factor (TGF)-β1, a fibrogenic marker regulated by IL-11. FA was also found to trigger an early phosphorylation of p38 and extracellular signal-regulated kinase (ERK)1/2 mitogen-activated protein kinases (MAPKs) in BEAS-2B cells, whose inhibition by ERK and p38 MAPK chemical inhibitors (U0126 and SB203580, respectively) counteracted FA-mediated induction of IL-11. In addition, FA increased phosphorylation of cAMP response element binding protein (CREB) and the use of small-interfering RNA targeting CREB demonstrated that this transcription factor was required for the up-regulation of IL-11 by FA. Implication of protein kinase C (PKC) in FA-induced IL-11 expression was moreover demonstrated by using RO-31-8220, a PKC inhibitor. We finally showed using SB203580 and RO-31-8220 that phosphorylation of CREB and CREB-promoter activity induced by FA are under the control of both p38 MAPK and PKC. Taken together, the results showed that FA uses different pathways to induce IL-11 expression in lung BEAS-2B cells. IL-11, well-known to contribute to lung inflammatory diseases, appears thus as a molecular target of FA, which could be involved in putative deleterious inflammatory and fibrogenic pulmonary effects of this VOC.
ISSN: 0300-483X

hal-00682486
https://hal.archives-ouvertes.fr/hal-00682486
DOI : 10.1016/j.tox.2011.11.011
PUBMED : 22138297

Éditeur(s) : HAL CCSD
Résumé : Macrophages (MΦ), well-known to play a key role in immune response, also respond to environmental toxic chemicals such as diesel exhaust particles (DEP), an air pollutant recently classified as carcinogenic to humans. MΦ are heterogeneous and plastic cells which activate according to their microenvironment into either an M1 subtype (so called classically activated or pro-inflammatory) under IFNγ and LPS stimulation or an M2 subtype (so called alternatively activated or anti-inflammatory) under IL-4 and/or IL-13 stimulation. However, potential effects of DEPs on M1/M2 MΦ polarization remain poorly documented. First, we characterized the expression marker of in vitro M-CSF-differentiated MΦ from human monocytes and activated into the M1 or M2 subtypes. Our main results show that M-CSF-generated MΦ considered as anti-inflammatory are actually able to switch to an M1 phenotype after IFNγ/LPS stimulation. Furthermore, the markers identified in this study were used to assess the impact of organic extracts of DEP (DEPe) on MΦ polarization and more generally on their physiology. DEPe alter some M1 and M2 markers expressed by polarized MΦ, without causing the overall inhibition of the M1 and M2 polarization process or the switch to a different phenotype. This phenotype alteration is associated with a decrease in the LPS-dependent inflammatory response in M1 MΦ and the chemotactic capacities in M2 MΦ. DEPe decrease the secretion of some cytokines and chemokines such as IL-6, IL-12p40 and CCL18 via AhR and/or Nrf2 activation. At the same time, we show that M1 and M2 MΦ in response to DEPe are able to secrete a sufficient level of a pro-fibrotic growth factor, the platelet derived growth factor B (PDGF-B) via AhR activation, leading to stimulation of lung fibroblast proliferation. Finally, these works show that DEPe have immunotoxic properties with regards to the physiology of human in vitro polarized MΦ. This immunotoxicity may then contribute to the deleterious effects of these urban environmental contaminants on human health.
Les macrophages (MΦ), des cellules clefs de la réponse immunitaire peuvent répondre à des contaminants environnementaux comme les particules diesel (DEP), des polluants atmosphériques récemment classés cancérigènes pour l'Homme. Les MΦ sont des cellules hétérogènes et plastiques qui s'activent en fonction de leur microenvironnement soit en MΦ M1 (dits classiquement activés ou pro-inflammatoires) sous l'effet de l'INFγ et du LPS soit en MΦ M2 (dits alternativement activés ou réparateurs) sous l'effet de l'IL-4 et/ou de l'IL-13. Les effets des DEP sur la polarisation M1/M2 des MΦ restent peu documentés. Nous avons dans un premier temps caractérisé l'expression des marqueurs des MΦ différenciés in vitro en présence de M-CSF à partir de monocytes humains et polarisés en sous-type M1 ou M2. Nos principaux résultats montrent que les MΦ différenciés au M-CSF considérés comme des MΦ anti-inflammatoires, sont en réalité capables de s'activer vers un phénotype M1 après une stimulation au LPS/IFNγ. De plus, les marqueurs mis en évidence au cours de ce travail ont permis d'évaluer l'impact d'extraits organiques de DEP (DEPe) sur la polarisation des MΦ et plus généralement sur leur physiologie. Les DEPe altèrent l'expression de certains marqueurs M1 et M2 des MΦ, sans toutefois provoquer d'inhibition globale des processus de polarisation M1 et M2 ou de transition d'un phénotype vers un autre. Cette altération du phénotype est associée à une diminution de la réponse inflammatoire LPS-dépendante dans les MΦ M1 et des capacités chimiotactiques des MΦ M2. Les DEPe diminuent la sécrétion de certaines cytokines et chimiokines comme l'IL-6, l'IL-12p40 et le CCL18 via l'activation d'AhR et/ou de Nrf2. Parallèlement, nous montrons que les MΦ M1 et M2 exposés aux DEPe sécrètent le platelet deried growth factor B (PDGF-B), un facteur de croissance profibrosant, via l'activation d'AhR en quantité suffisante pour stimuler la prolifération de fibroblastes pulmonaires. Au total, ces travaux démontrent que les DEP possèdent des propriétés immunotoxiques vis-à-vis de la physiologie des macrophages humains polarisés in vitro. Cette immunotoxicité pourrait participer aux effets délétères de ces contaminants environnementaux urbains sur la santé humaine.
https://tel.archives-ouvertes.fr/tel-01188679

NNT : 2015REN1S011
tel-01188679
https://tel.archives-ouvertes.fr/tel-01188679
https://tel.archives-ouvertes.fr/tel-01188679/document
https://tel.archives-ouvertes.fr/tel-01188679/file/JAGUIN_Marie.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: Early in life, cystic fibrosis (CF) patients are infected with microorganisms. The role of macrophages has largely been underestimated in literature, whereas the focus being mostly on neutrophils and epithelial cells. Macrophages may however play a significant role in the initiating stages of this disease, via an inability to act as a suppressor cell. Yet macrophage dysfunction may be the first step in cascade of events leading to chronic inflammation/infection in CF. Moreover, reports have suggested that CFTR contribute to altered inflammatory response in CF by modification of normal macrophage functions. OBJECTIVES: In order to highlight possible intrinsic macrophage defects due to impaired CFTR, we have studied inflammatory cytokines secretions, recognition of pathogens and phagocytosis in peripheral blood monocyte-derived macrophages from stable adult CF patients and healthy subjects (non-CF). RESULTS: In CF macrophage supernatants, concentrations of sCD14, IL-1β, IL-6, TNF-α and IL-10 were strongly raised. Furthermore expression of CD11b and TLR-5 were sorely decreased on CF macrophages. Beside, no difference was observed for mCD14, CD16, CD64, TLR-4 and TLR1/TLR-2 expressions. Moreover, a strong inhibition of phagocytosis was observed for CF macrophages. Elsewhere CFTR inhibition in non-CF macrophages also led to alterations of phagocytosis function as well as CD11b expression. CONCLUSIONS: Altogether, these findings demonstrate excessive inflammation in CF macrophages, characterized by overproduction of sCD14 and inflammatory cytokines, with decreased expression of CD11b and TLR-5, and impaired phagocytosis. This leads to altered clearance of pathogens and non-resolution of infection by CF macrophages, thereby inducing an exaggerated pro-inflammatory response.
ISSN: 1932-6203

inserm-00872278
http://www.hal.inserm.fr/inserm-00872278
http://www.hal.inserm.fr/inserm-00872278/document
http://www.hal.inserm.fr/inserm-00872278/file/Impaired_Functions.accepted.pdf
DOI : 10.1371/journal.pone.0075667

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Diesel exhaust particles (DEPs) are common environmental air pollutants primarily affecting the lung. DEPs or chemicals adsorbed on DEPs also exert extra-pulmonary effects, including alteration of hepatic drug detoxifying enzyme expression. The present study was designed to determine whether organic DEP extract (DEPe) may target hepatic drug transporters that contribute in a major way to drug detoxification. Using primary human hepatocytes and transporter-overexpressing cells, DEPe was first shown to strongly inhibit activities of the sinusoidal solute carrier (SLC) uptake transporters organic anion-transporting polypeptides (OATP) 1B1, 1B3 and 2B1 and of the canalicular ATP-binding cassette (ABC) efflux pump multidrug resistance-associated protein 2, with IC50 values ranging from approximately 1 to 20 μg/mL and relevant to environmental exposure situations. By contrast, 25 μg/mL DEPe failed to alter activities of the SLC transporter organic cation transporter (OCT) 1 and of the ABC efflux pumps P-glycoprotein and bile salt export pump (BSEP), whereas it only moderately inhibited those of sodium taurocholate co-transporting polypeptide and of breast cancer resistance protein (BCRP). Treatment by 25 μg/mL DEPe was next demonstrated to induce expression of BCRP at both mRNA and protein level in cultured human hepatic cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B3, OATP2B1, OCT1 and BSEP. Such changes in transporter expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a reference activator of the aryl hydrocarbon receptor (AhR) pathway. This suggests that DEPe, which is enriched in known ligands of AhR like polycyclic aromatic hydrocarbons, alters drug transporter expression via activation of the AhR cascade. Taken together, these data established human hepatic transporters as targets of organic chemicals containing in DEPs, which may contribute to their systemic effects through impairing hepatic transport of endogenous compound or drug substrates of these transporters.
ISSN: 1932-6203

Droits : http://creativecommons.org/licenses/by/
hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01138535/file/Regulation%20of%20human%20hepatic%20drug.pdf
DOI : 10.1371/journal.pone.0121232

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Macrophages (MΦ), well-known to play an important role in immune response, also respond to environmental toxic chemicals such as diesel exhaust particles (DEP). Potential effects of DEPs towards MΦ polarization, a key hall-mark of MΦ physiology, remain however poorly documented. This study was therefore designed to evaluate the effects of a reference DEP extract (DEPe) on human MΦ polarization. Human blood monocytes-derived MΦ were incubated with IFNγ+LPS or IL-4 to obtain M1 and M2 subtypes, respectively; a 24 h exposure of polarizing MΦ to 10 μg/ml DEPe was found to impair expression of some macrophagic M1 and M2 markers, without however overall inhibition of M1 and M2 polarization processes. Notably, DEPe treatment increased the secretion of the M1 marker IL-8 and the M2 marker IL-10 in both MΦ subtypes, whereas it reduced lipopolysaccharide-induced IL-6 and IL-12p40 secretion in M1 MΦ. In M2 MΦ, DEPe exposure led to a reduction of CD200R expression and of CCL17, CCL18 and CCL22 secretion, associated with a lower chemotaxis of CCR4-positive cells. DEPe activated the Nrf2 and AhR pathways and induced expression of their reference target genes such as Hmox-1 and cytochrome P-4501B1 in M1 and M2 MΦ. Nrf2 or AhR silencing through RNA interference prevented DEPe-related down-regulation of IL-6. AhR silencing also inhibited the down-secretion of IL-12p40 and CCL18 in M1- and M2-DEPe-exposed MΦ, respectively. DEPs are therefore likely to alter expression of some M1 and M2 markers in an AhR- and Nrf2-dependent manner; such regulations may contribute to deleterious immune effects of atmospheric DEP.
ISSN: 1932-6203

hal-01122723
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122723
PUBMED : 25710172
DOI : 10.1371/journal.pone.0116560

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Dairy working increases the prevalence of lower airway respiratory diseases, especially COPD and asthma. Epidemiological studies have reported that chronic inhalation of organic dusts released during specific daily tasks could represent a major risk factor for development of these pathologies in dairy workers. Knowledge on size, nature and biological activity of such organic dusts remain however limited. OBJECTIVE: To compare size distribution, microbial composition and cellular effects of dusts liberated by the spreading of straw bedding in five French dairy farms located in Brittany. RESULTS: Mechanized distribution of straw bedding generated a cloud of inhalable dusts in the five dairy farms' barns. Thoracic particles having a 3-7.5µm size constituted 58.9-68.3% of these dusts. Analyses of thoracic dusts by next generation sequencing showed that the microbial dust composition differed between the five French farms, although Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria represent more than 97.5% of the bacterial phyla detected in each sample. Several bacteria genera comprising of human pathogenic species, such as Pseudomonas, Staphylococcus, Thermoactinomyces or Saccharopolyspora were identified. Cladosporium and Alternaria fungal genera, which are potent environmental determinants of respiratory symptoms, were detected in dusts collected in the five farms and their levels reached 15.5-51.1% and 9-24.7% of assignable fungal sequences in each sample, respectively. Finally, all dust samples significantly and strongly increased the expression of the pro-inflammatory TNF-α, IL-1β, IL-6 and IL-8 cytokines at both mRNA and protein levels in human monocyte-derived macrophages. Their effects were dose-dependent and detectable from 1µg/ml. The intensity of the macrophage responses however differed according to the samples. CONCLUSIONS: Our results strengthen the hypothesis that organic dusts released during the distribution of straw bedding are mainly constituted of thoracic particles which are small enough to deposit on lower bronchial epithelium of dairy farmers and induce inflammation.
Environmental Research

hal-01579610
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01579610
DOI : 10.1016/j.envres.2017.07.025
PUBMED : 28735230

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The heterodimeric L-type amino acid transporter (LAT) 1/ CD98hc is overexpressed in lung cancers with a poor prognosis factor. Factors that contribute to LAT1/CD98hc overexpression in lung cells remain however to be determined, but the implication of atmospheric pollution can be suspected. The present study was therefore designed to analyze the effects of diesel exhaust particle (DEP) extract (DEPe) on LAT1/CD98hc expression in bronchial epithelial BEAS-2B cells. Exposure to DEPe up-regulated LAT1 and CD98hc mRNA levels in a concentration-dependent manner, with DEPe EC50 values (around 0.2 μg/mL) relevant to environmental situations. DEPe concomitantly induced LAT1/CD98hc protein expression and LAT1-mediated leucine accumulation in BEAS-2B cells. Inhibition of the aryl hydrocarbon receptor (AhR) pathway through the use of a chemical AhR antagonist or the siRNA-mediated silencing of AhR expression was next found to prevent DEPe-mediated induction of LAT1/CD98hc, indicating that this regulation depends on AhR, known to be activated by major chemical DEP components like polycyclic aromatic hydrocarbons. DEPe exposure was finally shown to induce mRNA expression and activity of matrix metalloproteinase (MMP)-2 in BEAS-2B cells, in a CD98hc/focal adhesion kinase (FAK)/extracellular regulated kinase (ERK) manner, thus suggesting that DEPe-mediated induction of CD98hc triggers activation of the integrin/FAK/ERK signaling pathway known to be involved in MMP-2 regulation. Taken together, these data demonstrate that exposure to DEPe induces functional overexpression of the amino acid transporter LAT1/CD98h in lung cells. Such a regulation may participate to pulmonary carcinogenic effects of DEPs, owing to the well-documented contribution of LAT1 and CD98hc to cancer development.
ISSN: 0041-008X

hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01237095/file/Aryl%20hydrocarbon%20receptor-dependent%20up-regulation_accepted.pdf
DOI : 10.1016/j.taap.2015.11.014