L-carnitine reduces acute lung injury via mitochondria modulation and inflammation control in pulmonary macrophages.

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a critical respiratory syndrome with limited effective interventions. Lung macrophages play a critical role in the pathogenesis of abnormal inflammatory response in the syndrome. Recently, impaired fatty acid oxidation (FAO), one of the key lipid metabolic signalings, was found to participate in the onset and development of various lung diseases, including ALI/ARDS. Lipid/fatty acid contents within mouse lungs were quantified using the Oil Red O staining. The protective effect of FAO activator L-carnitine (Lca, 50, 500, or 5 mg/mL) was evaluated by cell counting kit 8 (CCK-8) assay, real-time quantitative PCR (qPCR), ELISA, immunoblotting, fluorescence imaging, and fluorescence plate reader detection in lipopolysaccharide (LPS) (100 ng/mL)-stimulated THP-1-derived macrophages. The in vivo efficacy of Lca (300 mg/kg) was determined in a 10 mg/kg LPS-induced ALI mouse model. We found for the first time that lipid accumulation in pulmonary macrophages was significantly increased in a classical ALI murine model, which indicated disrupted FAO induced by LPS. Lca showed potent anti-inflammatory and antioxidative effects on THP-1 derived macrophages upon LPS stimulation. Mechanistically, Lca was able to maintain FAO, mitochondrial activity, and ameliorate mitochondrial dynamics. In the LPS-induced ALI mouse model, we further discovered that Lca inhibited neutrophilic inflammation and decreased diffuse damage, which might be due to the preservation of mitochondrial homeostasis. These results broadened our understanding of ALI/ARDS pathogenesis and provided a promising drug candidate for this syndrome.

Interplay between alveolar epithelial and dendritic cells and Mycobacterium tuberculosis.

The innate response plays a crucial role in the protection against tuberculosis development. Moreover, the initial steps that drive the host-pathogen interaction following Mycobacterium tuberculosis infection are critical for the development of adaptive immune response. As alveolar Mϕs, airway epithelial cells, and dendritic cells can sense the presence of M. tuberculosis and are the first infected cells. These cells secrete mediators, which generate inflammatory signals that drive the differentiation and activation of the T lymphocytes necessary to clear the infection. Throughout this review article, we addressed the interaction between epithelial cells and M. tuberculosis, as well as the interaction between dendritic cells and M. tuberculosis. The understanding of the mechanisms that modulate those interactions is critical to have a complete view of the onset of an infection and may be useful for the development of dendritic cell-based vaccine or immunotherapies.

Anti-inflammatory effect of octyl gallate in alveolar macrophages cells and mice with acute lung injury.

Acute lung injury (ALI) is an inflammatory process, and has high incidence and mortality. ALI and the acute respiratory distress syndrome are two common complications worldwide that result in acute lung failure, sepsis, and death. Pro-inflammatory substances, such as cytokines and chemokines, are responsible for activating the body's defense mechanisms and usually mediate inflammatory processes. Therefore, the research of substances that decrease the uncontrolled response of organism is seen as potential for patients with ALI. Octyl gallate (OG) is a phenolic compound with therapeutic actions namely antimicrobial, antiviral, and antifungal. In this study, we evaluated its action on lipopolysaccharide (LPS)-activated alveolar macrophages RAW 264.7 cells and ALI in male mice. Our results demonstrated protective effects of OG in alveolar macrophages activated with LPS and mice with ALI. The OG treatment significantly decreased the inflammatory markers in both studies in vitro and in vivo. The data suggested that OG can act as an anti-inflammatory agent for ALI.

Focal ischemic stroke leads to lung injury and reduces alveolar macrophage phagocytic capability in rats.

BACKGROUND: Ischemic stroke causes brain inflammation, which we postulate may result in lung damage. Several studies have focused on stroke-induced immunosuppression and lung infection; however, the possibility that strokes may trigger lung inflammation has been overlooked. We hypothesized that even focal ischemic stroke might induce acute systemic and pulmonary inflammation, thus altering respiratory parameters, lung tissue integrity, and alveolar macrophage behavior. METHODS: Forty-eight Wistar rats were randomly assigned to ischemic stroke (Stroke) or sham surgery (Sham). Lung function, histology, and inflammation in the lung, brain, bronchoalveolar lavage fluid (BALF), and circulating plasma were evaluated at 24 h. In vitro, alveolar macrophages from naïve rats (unstimulated) were exposed to serum or BALF from Sham or Stroke animals to elucidate possible mechanisms underlying alterations in alveolar macrophage phagocytic capability. Alveolar macrophages and epithelial and endothelial cells of Sham and Stroke animals were also isolated for evaluation of mRNA expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. RESULTS: Twenty-four hours following ischemic stroke, the tidal volume, expiratory time, and mean inspiratory flow were increased. Compared to Sham animals, the respiratory rate and duty cycle during spontaneous breathing were reduced, but this did not affect lung mechanics during mechanical ventilation. Lungs from Stroke animals showed clear evidence of increased diffuse alveolar damage, pulmonary edema, and inflammation markers. This was associated with an increase in ultrastructural damage, as evidenced by injury to type 2 pneumocytes and endothelial cells, cellular infiltration, and enlarged basement membrane thickness. Protein levels of proinflammatory mediators were documented in the lung, brain, and plasma (TNF-α and IL-6) and in BALF (TNF-α). The phagocytic ability of macrophages was significantly reduced. Unstimulated macrophages isolated from naïve rats only upregulated expression of TNF-α and IL-6 following exposure to serum from Stroke rats. Exposure to BALF from Stroke or Sham animals did not change alveolar macrophage behavior, or gene expression of TNF-α and IL-6. IL-6 expression was increased in macrophages and endothelial cells from Stroke animals. CONCLUSIONS: In rats, focal ischemic stroke is associated with brain-lung crosstalk, leading to increased pulmonary damage and inflammation, as well as reduced alveolar macrophage phagocytic capability, which seems to be promoted by systemic inflammation.

Air pollution and its relationship to lung function among adolescents from Taubate, São Paulo, Brazil.

BACKGROUND: This paper sought to evaluate individual exposure to air pollution by quantifying the carbon in alveolar macrophages (AMs) and its relationship to lung function. We also examined the proximity of participants' residences to the Presidente Dutra highway (PDH) in adolescents with asthma from Taubaté, São Paulo, Brazil. METHODS: This descriptive study examined fifty 13- to 14-year-old adolescents with asthma identified by the International Study of Asthma and Allergies in Childhood (ISAAC) in Taubaté. These adolescents underwent spirometry and sputum induction via the inhalation of 3% hypertonic saline (HSS). Sputum was collected after each nebulisation, and forced expiratory flow in one second (FEV1) was measured. The collected sputum was stored and transported to the laboratory; it was then processed and analysed for ultrafine particles (≤100nm). This analysis was correlated with the residence location and FEV1 of each adolescent. RESULTS: A total of 39 adolescents completed the study. The comparison of the carbon fraction within macrophages (CA/MA) showed no differences according to residence in relation to the PDH (p=0.758). After adjustment, a mixed linear model with FEV1 as the dependent variable and CA/MA, location, and evaluation condition as the predictors found that the interactions among the variables were not significant. CONCLUSIONS: The amount of carbon present within the AMs of adolescents with asthma was not correlated with either lung function or residence location. Evaluations of the topography and local climatic conditions in Taubaté should be considered in future studies.

Acute Lung Injury in Response to Intratracheal Instillation of Lipopolysaccharide in an Animal Model of Emphysema Induced by Elastase.

The response of lungs with emphysema to an acute lung injury (ALI) remains unclear. This study compared the lung response to intratracheal instillation of lipopolysaccharide (LPS) in rats with and without emphysema. Twenty-four Wistar rats were randomized to four groups: control group (C-G), ALI group (ALI-G), emphysema group (E-G), emphysema and ALI group (E-ALI-G). Euthanasia and the following analysis were performed 24 h after ALI induction: lung histology, bronchoalveolar lavage (BAL), mRNA expression of inflammatory mediators, and blood gas measures. The histological analysis showed that animals of ALI-G (0.55 ± 0.15) and E-ALI-G (0.69 ± 0.08) had a higher ALI score compared to C-G (0.12 ± 0.04) and E-G (0.16 ± 0.04) (p < 0.05). The analysis of each component of the score demonstrated that ALI-G and E-ALI-G had greater alveolar and interstitial neutrophil infiltration, as well as greater amount of alveolar proteinaceous debris. Comparing the two groups that received LPS, there was a trend of higher ALI in the E-ALI-G, specially due to a higher neutrophil infiltration in the alveolar spaces and a higher septal thickening. Total cell count (E-G = 3.09 ± 0.83; ALI-G = 4.45 ± 1.9; E-ALI-G = 5.9 ± 2.1; C-G = 0.73 ± 0.37 × 105) and neutrophil count (E-G = 0.69 ± 0.35; ALI-G = 2.53 ± 1.09; E-ALI-G = 3.86 ± 1.4; C-G = 0.09 ± 0.07 × 105) in the BAL were higher in the groups E-G, ALI-G, and E-ALI-G when compared to C-G (p < 0.05). The IL-6, TNF-α, and CXCL2 mRNA expressions were higher in the animals that received LPS (ALI-G and E-ALI-G) compared to the C-G and E-G (p < 0.05). No statistically significant difference was observed in the BAL cellularity and in the expression of inflammatory mediators between the ALI-G and the E-ALI-G. The severity of ALI in response to intratracheal instillation of LPS did not show difference in rats with and without intratracheal-induced emphysema.

Relation between neonatal malnutrition and gene expression: inflammasome function in infections caused by Candida Albicans.

PURPOSE: To investigate the effects of neonatal malnutrition followed by nutritional replacement on the signaling mechanisms developed by the inflammasome complex by analyzing the expression of the targeted TLR2, TLR4, NLRP3, caspase-1 and release of IL-1ß and IL-18 by alveolar macrophages infected in vitro with Candida albicans. METHODS: Male Wistar rats (n = 24), 90-120 days, were suckled by mothers whose diet during lactation contained 17 % protein in the nourish group and 8 % protein in the malnourished group. After weaning, both groups were fed a normal protein diet. Macrophages were obtained after tracheostomy, through the collection of bronchoalveolar lavage fluid. The quantification of the expression levels of targets (TLR2, TLR4, NLRP3 and caspase-1) was performed by real-time RT-PCR. Production of cytokines was performed by ELISA. RESULTS: The malnourished animals during lactation showed reduced body weight from the fifth day of life, remaining until adulthood. Further, the model applied malnutrition induced a lower expression of TLR4 and caspase-1. The quantification of the TLR2 and NLRP3, as well as the release of IL-1ß and IL-18, was not different between groups of animals nourished and malnourished. The system challenged with Candida albicans showed high expression levels of all targets in the study. CONCLUSIONS: The tests demonstrate nutritional restriction during critical periods of development, although nutritional supplementation may compromise defense patterns in adulthood in a timely manner, preserving distinct signaling mechanism, so that the individual does not become widely vulnerable to infections by opportunistic pathogens.

Role of IL-10 and TNF-α during Mycobacterium tuberculosis infection in murine alveolar macrophages.

Mycobacterium tuberculosis (Mtb) is known to be responsible for tuberculosis (TB), but the pathogenesis of this disease and the host defense mechanisms involved are, for the most part, poorly understood. In this study, we divided 30 male C57BL/6 mice into control and infection groups, and following injection with physiological saline or Mtb, respectively, euthanized five mice from each group on days 1, 3, and 7. TNF-α and IL-10 levels were measured by enzyme-linked immunosorbent assay and flow cytometry, with the latter also being performed to assess apoptosis rates. Protein expression of STAT3 and its phosphorylated form (p-STAT3) was analyzed by western blotting. After Mtb infection, TNF-α and IL-10 levels, alveolar macrophage apoptosis, and STAT3 and p-STAT3 expression increased significantly on days 1, 3, and 7 (P < 0.05), with maximum values on day 3. Furthermore, the Pearson correlation test showed that production of the cytokines TNF-α and IL-10 correlated strongly with expression of STAT3 and p-STAT3 proteins (P < 0.05). Taken together, our results suggest that the STAT3 signaling pathway might play a key role in the regulation of cell proliferation and alveolar macrophage apoptosis in response to Mtb. This provides a theoretical mechanism behind TB pathogenesis and host defense against Mtb, and contributes towards development of an effective treatment.

Lung tumors masquerading as desquamative interstitial pneumonia (DIP): report of 7 cases and review of the literature.

Malignant tumors in the lung (both primary and metastatic) rarely may be associated with markedly discohesive tumor cells, resulting in airspace filling reminiscent of "desquamative interstitial pneumonia" (DIP) on histopathology evaluation. A peculiar aspect of this growth pattern is the relatively bland appearance of the tumor cells, in many cases simulating benign alveolar macrophages at scanning magnification. We searched the Charles Carrington Memorial consultation files in the Department of Laboratory Medicine and Pathology at Mayo Clinic Arizona for instances of malignant tumors in lung simulating DIP, from 1992 to 2011. We identified 7 cases involving transbronchial biopsies, needle core samples, or resected lung specimens. Clinical, histopathologic, and immunohistochemical analyses of these 7 patients were performed, including detailed morphometric analysis of the individual tumor cells using calibrated measurement tools on digital images. We compared the results with those of a control group of 4 patients with benign DIP-macrophage reactions in smoking-related lung disease. The study group comprised 5 male and 2 female patients, 48 to 86 years in age (median: 67 y). The radiologic findings included lobar consolidation, localized ground-glass opacities, and 1 or more nodules. None of the patients had typical bilateral infiltrates of DIP. Microscopically, the lung parenchyma was dominated by the presence of prominent tumor cells filling alveolar spaces. Four patients had primary lung carcinoma (adenocarcinoma), whereas 3 had metastases from other sites, including a melanoma. Immunohistochemical staining studies were performed on 6 of 7 cases to establish the diagnosis. Nuclear diameter, cytoplasmic diameter, and nuclear/cytoplasmic (N/C) ratios in patient and control groups were compared using the Wilcoxon rank sum test. No significant difference in the diameters of nucleus and cytoplasm between cases and control groups (P=0.3447 and 0.7055, respectively) was seen, and only a marginally significant difference in N/C ratios (P=0.0890) was seen. A more complex analysis, generalized estimating equation analysis, showed a significant difference in N/C ratio between the 2 groups (P=0.0278). A "DIP-growth pattern" of malignant tumors in the lung is presented. Although the N/C ratio differences approached statistical significance when compared with controls, the key to diagnosis is the recognition of the malignant cytology of the tumor nuclei. Immunohistochemical studies (keratin or other markers) are helpful in establishing an accurate diagnosis in this setting.

Alterações da histoarquitetura pulmonar de camundongos neonatos expostos à hiperóxia / Alterations in the pulmonary histoarchitecture of neonatal mice exposed to hyperoxia

OBJETIVOS: Analisar os efeitos da exposição à hiperóxia (100% de oxigênio) sobre a histoarquitetura pulmonar de camundongos neonatos. MÉTODOS: Camundongos neonatos da linhagem Balb/c foram expostos à hiperóxia (GH) (100% de oxigênio) (n = 10) em uma câmara (15 x 20 x 30 cm) por 24 horas, com fluxo de 2 L/min. O grupo controle (GC) (n = 10) foi exposto a normóxia em um mesmo tipo de câmara e pelo mesmo tempo. Após a exposição, os animais foram sacrificados por decapitação, os pulmões foram removidos para análise histológica e processados de acordo com a rotina do laboratório. Cortes de 3 µm de espessura foram corados com hematoxilina e eosina (H&E). A análise morfométrica foi realizada com o objetivo de analisar macrófagos presentes na luz alveolar, densidade de superfície (Sv) de trocas gasosas, densidade de volume (Vv) de parênquima pulmonar e áreas de atelectasias. RESULTADOS: Foi verificada diminuição do número de macrófagos alveolares (MØ) no GH (GH = 0,08±0,01 MØ/mm²; GC = 0,18±0,03 MØ/mm²; p = 0,0475), Sv de troca gasosa no GH (GH = 8,08 ± 0,12 mm² /mm³; GC = 8,65 ± 0,20 mm² /mm³; p = 0,0233), Vv de parênquima pulmonar no GH (GH = 54,7/33,5/83,5 %/mm²; GC = 75/56,7/107,9 %/mm²; p < 0.0001) quando comparado com o GC. Entretanto, houve aumento de áreas de atelectasias no GH (GH = 17,5/11,3/38,4 atelectasia/mm²; GC = 14/6,1/24,4 atelectasia/mm²; p = 0,0166) quando comparado com o GC. CONCLUSÃO: Nossos resultados indicam que a hiperóxia promoveu alterações na histoarquitetura pulmonar, aumentando áreas de atelectasia e hemorragia alveolar difusa.

OBJECTIVES: To analyze the effects of exposure to hyperoxia (100% oxygen) on the lung histoarchitecture of neonatal mice. METHODS: Neonatal Balb/c mice were exposed to hyperoxia (HG) (100% oxygen) (n = 10) in a chamber (15 x 20 x 30 cm) for 24 horas ours with a flow of 2 L/min. The control group (CG) (n = 10) was exposed to normoxia in the same type of chamber and for the same time. After exposure, the animals were euthanized by decapitation; the lungs were removed and processed for histological examination according to the laboratory routine. Three-mm thick sections were stained with hematoxylin and eosin (H&E). The morphometric analysis was performed with in order to analyze the macrophages present in the alveolar lumen, surface density (Sv) of gas exchange, volume density (Vv) of lung parenchyma, and areas of atelectasis. RESULTS: A decrease in the number of alveolar macrophages (MØ) was observed in the HG (HG = 0.08±0.01 MØ/mm², CG = 0.18±0.03 MØ/mm², p = 0.0475), Sv of gas exchange in HG (HG = 8.08±0.12 mm² /mm³, CG = 8.65±0.20 mm² /mm³, p = 0.0233), Vv of lung parenchyma in HG (HG = 54.7/33.5/83.5%/ mm²; CG = 75/56.7/107.9%/mm², p < 0.0001) when compared with the CG. However, there was an increase in areas of atelectasis in HG (HG = 17.5/11.3/38.4 atelectasis/mm², CG = 14/6.1/24.4 atelectasis/mm², p = 0.0166) when compared with the CG. CONCLUSION: The present results indicate that hyperoxia caused alterations in lung histoarchitecture, increasing areas of atelectasis and diffuse alveolar hemorrhage.

Alterations in the pulmonary histoarchitecture of neonatal mice exposed to hyperoxia.

OBJECTIVES: To analyze the effects of exposure to hyperoxia (100% oxygen) on the lung histoarchitecture of neonatal mice. METHODS: Neonatal Balb/c mice were exposed to hyperoxia (HG) (100% oxygen) (n= 10) in a chamber (15 x 20 x 30 cm) for 24 hours with a flow of 2 L/min. The control group (CG) (n = 10) was exposed to normoxia in the same type of chamber and for the same time. After exposure, the animals were euthanized by decapitation; the lungs were removed and processed for histological examination according to the laboratory routine. Three-mm thick sections were stained with hematoxylin and eosin (H&E). The morphometric analysis was performed with in order to analyze the macrophages present in the alveolar lumen, surface density (Sv) of gas exchange, volume density (Vv) of lung parenchyma, and areas of atelectasis. RESULTS: A decrease in the number of alveolar macrophages (MØ) was observed in the HG (HG = 0.08 ±0.01 MØ/mm(2), CG = 0.18 ± 0.03 MØ/mm(2), p=0.0475), Sv of gas exchange in HG (HG = 8.08 ± 0.12 mm(2)/mm(3), CG=8.65 ± 0.20mm(2)/mm(3), p = 0.0233), Vv of lung parenchyma in HG (HG = 54.7/33.5/83.5%/mm(2); CG = 75/56.7/107.9%/mm(2), p<0.0001) when compared with the CG. However, there was an increase in areas of atelectasis in HG (HG = 17.5/11.3/38.4 atelectasis/mm(2), CG = 14/6.1/24.4 atelectasis/mm(2), p=0.0166) when compared with the CG. CONCLUSION: The present results indicate that hyperoxia caused alterations in lung histoarchitecture, increasing areas of atelectasis and diffuse alveolar hemorrhage.

Tumour necrosis factor receptors and apoptosis of alveolar macrophages during early infection with attenuated and virulent Mycobacterium bovis.

Apoptosis of macrophages has been reported as an effective host strategy to control the growth of intracellular pathogens, including pathogenic mycobacteria. Tumour necrosis factor-α (TNF-α) plays an important role in the modulation of apoptosis of infected macrophages. It exerts its biological activities via two distinct cell surface receptors, TNFR1 and TNFR2, whose extracellular domain can be released by proteolysis forming soluble TNF receptors (sTNFR1 and sTNFR2). The signalling through TNFR1 initiates the majority of the biological functions of TNF-α, leading to either cell death or survival whereas TNFR2 mediates primarily survival signals. Here, the expression of TNF-α receptors and the apoptosis of alveolar macrophages were investigated during the early phase of infection with attenuated and virulent mycobacteria in mice. A significant increase of apoptosis and high expression of TNFR1 were observed in alveolar macrophages at 3 and 7 days after infection with attenuated Mycobacterium bovis but only on day 7 in infection with the virulent M. bovis. Low surface expression of TNFR1 and increased levels of sTNFR1 on day 3 after infection by the virulent strain were associated with reduced rates of apoptotic macrophages. In addition, a significant reduction in apoptosis of alveolar macrophages was observed in TNFR1(-/-) mice at day 3 after bacillus Calmette-Guérin infection. These results suggest a potential role for TNFR1 in mycobacteria-induced alveolar macrophage apoptosis in vivo. In this scenario, shedding of TNFR1 seems to contribute to the modulation of macrophage apoptosis in a strain-dependent manner.

Chemical compositions and properties of Schinus areira L. essential oil on airway inflammation and cardiovascular system of mice and rabbits.

The main purpose was to investigate the effects of essential plant-oil of Schinus areira L. on hemodynamic functions in rabbits, as well as myocardial contractile strength and airways inflammation associated to bacterial endotoxin lipopolysaccharide (LPS) in mice. This study shows the important properties of the essential oil (EO) of S. areira studied and these actions on lung with significant inhibition associated to LPS, all of which was assessed in mice bronchoalveolar lavage fluid and evidenced by stability of the percentage of alveolar macrophages, infiltration of polymorphonuclear leukocytes and tumor necrosis factor-α concentration, and without pathway modifications in conjugated dienes activity. Clinical status (morbidity or mortality), macroscopic morphology and lung/body weight index were unaffected by the administration of the EO S. areira. Furthermore, the ex vivo analysis of isolated hearts demonstrated the negative inotropic action of the EO of S. areira in a mice model, and in rabbits changes in the hemodynamic parameters, such as a reduction of systolic blood pressure. We conclude that EO S. areira could be responsible for modifications on the cardiovascular and/or airway parameters.

11-Oxoaerothionin isolated from the marine sponge Aplysina fistularis shows anti-inflammatory activity in LPS-stimulated macrophages.

Marine sponges of the order Verongida are a rich source of biologically active bromotyrosine-derived secondary metabolites. However, none of these compounds are known to display anti-inflammatory activity. In the present investigation, we report the anti-inflammatory effects of 11-oxoaerothionin isolated from the Verongida sponge Aplysina fistularis. When RAW264.7 cells and primary macrophages were preincubated with 11-oxoaerothionin and stimulated with LPS (lipopolysaccharide), a concentration-dependent inhibition of iNOS(inducible nitric oxide synthase) protein and NO(2)(-) (Nitrite) production were observed. The same effect was observed when proinflammatory cytokines and PGE(2) (Prostaglandin E2) production was evaluated. In summary, we demonstrated that in the presence of LPS, 11-oxoaerothionin suppresses NO(2) and iNOS expression as well as inflammatory cytokines and PGE(2).

Alveolar macrophages in diabetes: friends or foes?

AMs constitute an important bridge between innate and adaptive immunity. AMs patrol the lungs against pathogens, remove senescent cells, and help repair tissue. AM function is altered in many diseases, including DM, where AM abnormal immune responses may worsen infections or lead to exacerbation of inflammatory reactions. In vivo experimental models have greatly contributed to our knowledge of AM function. Studies have shown that during hyperglycemic states, the phagocytic function of AMs and the expression of adhesion molecules may be altered, interfering with the recruitment of immune cells to the inflammatory site. Insulin treatment seems to recover the normal function of impaired AMs. However, much research is still needed to characterize AMs and to better understand their role in inflammation and infection, particularly in diabetic patients. In this review, we attempt to explore recently accumulated knowledge about AM function and how this function is deficient in DM. Additionally, AM polarization is compared briefly with that of T cells, and this may interfere with how immune response is driven. This review discusses how impaired AMs lead to an aberrant immune response that contributes to worsening infection and autoimmunity, opening up discussion for future work in the field.

Membrane microdomain components of Histoplasma capsulatum yeast forms, and their role in alveolar macrophage infectivity.

Analysis of membrane lipids of Histoplasma capsulatum showed that ~40% of fungal ergosterol is present in membrane microdomain fractions resistant to treatment with non-ionic detergent at 4°C. Specific proteins were also enriched in these fractions, particularly Pma1p a yeast microdomain protein marker (a plasma membrane proton ATPase), a 30kDa laminin-binding protein, and a 50kDa protein recognized by anti-α5-integrin antibody. To better understand the role of ergosterol-dependent microdomains in fungal biology and pathogenicity, H. capsulatum yeast forms were treated with a sterol chelator, methyl-beta-cyclodextrin (mßCD). Removal of ergosterol by mßCD incubation led to disorganization of ergosterol-enriched microdomains containing Pma1p and the 30kDa protein, resulting in displacement of these proteins from detergent-insoluble to -soluble fractions in sucrose density gradient ultracentrifugation. mßCD treatment did not displace/remove the 50kDa α5-integrin-like protein nor had effect on the organization of glycosphingolipids present in the detergent-resistant fractions. Ergosterol-enriched membrane microdomains were also shown to be important for infectivity of alveolar macrophages; after treatment of yeasts with mßCD, macrophage infectivity was reduced by 45%. These findings suggest the existence of two populations of detergent-resistant membrane microdomains in H. capsulatum yeast forms: (i) ergosterol-independent microdomains rich in integrin-like proteins and glycosphingolipids, possibly involved in signal transduction; (ii) ergosterol-enriched microdomains containing Pma1p and the 30kDa laminin-binding protein; ergosterol and/or the 30kDa protein may be involved in macrophage infectivity.

Endogenous annexin A1 counter-regulates bleomycin-induced lung fibrosis.

BACKGROUND: The balancing functions of pro/anti-inflammatory mediators of the complex innate responses have been investigated in a variety of experimental inflammatory settings. Annexin-A1 (AnxA1) is one mediator of endogenous anti-inflammation, affording regulation of leukocyte trafficking and activation in many contexts, yet its role in lung pathologies has been scarcely investigated, despite being highly expressed in lung cells. Here we have applied the bleomycin lung fibrosis model to AnxA1 null mice over a 21-day time-course, to monitor potential impact of this mediator on the control of the inflammatory and fibrotic phases. RESULTS: Analyses in wild-type mice revealed strict spatial and temporal regulation of the Anxa1 gene, e.g. up-regulation in epithelial cells and infiltrated granulocytes at day 7, followed by augmented protein levels in alveolar macrophages by day 21. Absence of AnxA1 caused increases in: i) the degree of inflammation at day 7; and ii) indexes of fibrosis (assessed by deposition of hydroxyproline in the lung) at day 7 and 21. These alterations in AnxA1 null mice were paralleled by augmented TGF-ß1, IFN-γ and TNF-α generation compared to wild-type mice. Finally, treatment of wild type animals with an AnxA1 peptido-mimetic, given prophylactically (from day 0 to 21) or therapeutically (from day 14 onward), ameliorated both signs of inflammation and fibrosis. CONCLUSION: Collectively these data reveal a pathophysiological relevance for endogenous AnxA1 in lung inflammation and, more importantly, fibrosis, and may open new insights for the pharmacological treatment of lung fibrosis.

Phenotypic and functional characterization of pulmonary macrophages subpopulations after intratracheal injection of Paracoccidioides brasiliensis cell wall components.

A shift in the activation of pulmonary macrophages characterized by an increase of IL-1, TNF-α and IL-6 production has been induced in mice infected with Paracoccidioides brasiliensis. It is still unclear whether a functional shift in the resident alveolar macrophage population would be responsible for these observations due to the expression of cell surface molecules. We investigated pulmonary macrophages by flow cytometry from mice treated with P. brasiliensis derivatives by intratracheal route. In vivo labeling with the dye PKH26GL was applied to characterize newly recruited pulmonary macrophages from the bloodstream. Pulmonary macrophages from mice inflamed with P. brasiliensis derivatives showed a high expression of the surface antigens CD11b/CD18 and CD23 among several cellular markers. The expression of these markers indicated a pattern of activation of a subpopulation characterized as CD11b+ or CD23+, which was modulated in vitro by IFN-γ and IL-4. Analysis of monocytes labelled with PKH26GL demonstrated that CD11b+ cells did infiltrate the lung exhibiting a proinflammatory pattern of activation, whereas CD23+ cells were considered to be resident in the lung. These findings may contribute to better understand the pathology of lung inflammation caused by P. brasiliensis infection.

[Cyclooxygenase-2 polymorphisms and bronchoalveolar lavage cellularity of sarcoidosis]. / El polimorfismo COX2.8473t>C del gen de la ciclooxigenasa-2 está asociado al cociente CD4/CD8 del lavado broncoalveolar en la sarcoidosis.

OBJECTIVES: Recent studies have found cyclooxygenase-2 (COX-2) and its polymorphisms to be associated with sarcoidosis, being it significantly decreased in alveolar macrophages, with no information on the relationship between these polymorphisms and the rest of cells in bronchoalveolar layage (BAL). The present study aimed to investigate the potential association between COX-2 gene polymorphisms and the BAL cell profile including the CD4/CD8 ratio. MATERIAL AND METHODS: This observational cross-sectional study involved six hospitals in Spain. Patients diagnosed with sarcoidosis with a BAL performed were included. The following variables were recorded: age, gender, initial diagnostic methods, serum angiotensin-converting enzyme levels, pulmonary function tests, radiological stage, and the cellularity and CD4/CD8 ratio from BAL. Genotyping of four COX-2 polymorphisms (COX2.5909T>G, COX2.8473T>C, COX2.926G>C, and COX2.3050G>C) was undertaken on DNA extracted from peripheral blood lymphocytes using fluorescent hybridization probes. The relationship between the polymorphisms and the cellularity was done by means of a multiple linear regression, adjusting for gender. RESULTS: A total of 51 sarcoid patients (23 males, mean age: 45 +/- 15 years) were studied. CD4/CD8 ratio was significantly higher among homozygote allele C carriers of the polymorphism COX2.8473T>C (CC 11.2 +/- 5.5 vs. CT+TT 4.4 +/- 3.5; p = 0.022; beta = 7.43; 95% CI 1.38 - 13.48). Although several differences were observed in other cell groups, they did not reach the statistical significance level. CONCLUSIONS: In patients diagnosed with sarcoidosis, there seems to be a relationship between COX2.8473 polymorphism and CD4/CD8 ratio from BAL.

Pre-exposure to Staphylococcal enterotoxin A exacerbates the pulmonary allergic eosinophil recruitment in rats.

Gram-positive Staphylococcus aureus releases classical enterotoxins which aggravates allergic airway diseases. However, little is known about the mechanisms underlying the cell influx exacerbation in asthmatic individuals under exposure to Staphylococcal enterotoxins. We therefore aimed to investigate the effects of airways exposure to Staphylococcal enterotoxin A (SEA) to pulmonary leukocyte recruitment in rats sensitized and challenged with ovalbumin (OVA). Rats were exposed to SEA at 4h prior to OVA challenge or at 4h post-OVA challenge. Bronchoalveolar lavage (BAL) fluid, bone marrow and lung tissue were obtained at 24h after OVA challenge. Pre-exposure to SEA markedly enhanced the eosinophil counts in both BAL fluid and pulmonary tissue in OVA-challenged rats, whereas neutrophil and mononuclear cell counts remained unchanged. In bone marrow, pre-exposure to SEA alone significantly increased the number of eosinophils, and that was further increased in OVA-challenged rats. Exposure to SEA post-OVA challenge did not affect the number of eosinophils, neutrophils and mononuclear cells in BAL fluid. Pre-exposure to the endotoxin lipopolyssacharide (LPS) in OVA-challenged animals rather enhanced the neutrophil number in BAL fluid. In rats pre-exposed to SEA and OVA-challenged, a marked elevation in the levels of TNF-alpha and eotaxin (but not of IL-10) in BAL fluid was observed. The eotaxin levels increased by about of 3-fold in alveolar macrophages treated with SEA in vitro. In conclusion, airways pre-exposure to SEA causes a selective increase in eosinophil number in BAL fluid and bone marrow of OVA-challenged rats by mechanisms involving enhancement of TNF-alpha and eotaxin synthesis.