Genetic Variants of Surfactant Proteins A, B, C, and D in Bronchopulmonary Dysplasia

BPD_28D (O2 dependency at 28 days of life) and BPD_36W (O2 dependency at 36 wks post-menstrual age) are diseases of prematurely born infants exposed to mechanical ventilation and/or oxygen supplementation. In order to determine whether genetic variants of surfactant proteins (SPs-A, B, C, and D) and SP-B-linked microsatellite markers are risk factors in BPD, we performed a family based association study using a Greek study group of 71 neonates (<30 wks gestational age) from 60 families with, 52 BPD_28D and 19 BPD_36W, affected infants. Genotyping was performed using newly designed pyrosequencing assays and previously published methods. Associations between genetic variants of SPs and BPD subgroups were determined using Transmission Disequilibrium Test (TDT) and Family Based Association Test (FBAT). Significant associations (p ≤ 0.01) were observed for alleles of SP-B and SP-B-linked microsatellite markers, and haplotypes of SP-A, SP-D, and SP-B. Specifically, allele B-18_C associated with susceptibility in BPD_36W. Microsatellite marker AAGG_6 associated with susceptibility in BPD_28D/36W group. Haplotype analysis revealed ten susceptibility and one protective haplotypes for SP-B and SP-B-linked microsatellite markers and two SP-A-SP-D protective haplotypes. The data indicate that SP loci are linked to BPD. Studies in different study groups and/or of larger sample size are warranted to confirm these observations and delineate genetic background of BPD subgroups

Quantitative expression of osteopontin in nasal mucosa of patients with allergic rhinitis: effects of pollen exposure and nasal glucocorticoid treatment

<p>Abstract</p> <p>Background</p> <p>Osteopontin (OPN) is a multifunctional cytokine that has been primarily investigated in Th1 diseases. Recently, it has also been implicated in Th2-mediated allergic diseases, such as asthma. The expression of OPN in allergic rhinitis (AR) is currently unknown, as is the effect of intranasal glucocorticosteroids (GCs) on that expression.</p> <p>Methods</p> <p>Subjects with AR were randomised to receive treatment with fluticasone propionate (FP) (n = 12) or a placebo (n = 16) over the grass pollen season and nasal biopsies were taken prior to, and during the season. OPN expression in the nasal mucosa was examined with immunohistochemistry. Healthy non-AR controls (n = 5) were used as a comparator.</p> <p>Results</p> <p>OPN expression was detected in epithelial cells, subepithelial infiltrating/inflammatory cells and cells lining the vessels and glands of all subjects. Comparison of the pre- and peak-pollen season biopsy sections in placebo treated patients revealed no increase in OPN expression during the grass pollen season (5.7% vs 6.4%). Treatment with a local glucocorticosteroid did not alter the expression of OPN during pollen exposure (6.2% vs 6.7%).</p> <p>Conclusion</p> <p>OPN has been increasingly associated with the pathogenesis of various Th2-mediated diseases. However, our finding that the OPN expression in the nasal mucosa of AR patients is not significantly affected by allergen exposure and is comparable to that of the healthy controls, suggests that intracellular OPN is not directly involved in the pathogenesis of allergic rhinitis.</p

Activin-A induces regulatory T cells that suppress T helper cell immune responses and protect from allergic airway disease

Activin-A is a pleiotropic cytokine that participates in developmental, inflammatory, and tissue repair processes. Still, its effects on T helper (Th) cell–mediated immunity, critical for allergic and autoimmune diseases, are elusive. We provide evidence that endogenously produced activin-A suppresses antigen-specific Th2 responses and protects against airway hyperresponsiveness and allergic airway disease in mice. Importantly, we reveal that activin-A exerts suppressive function through induction of antigen-specific regulatory T cells that suppress Th2 responses in vitro and upon transfer in vivo. In fact, activin-A also suppresses Th1-driven responses, pointing to a broader immunoregulatory function. Blockade of interleukin 10 and transforming growth factor β1 reverses activin-A–induced suppression. Remarkably, transfer of activin-A–induced antigen-specific regulatory T cells confers protection against allergic airway disease. This beneficial effect is associated with dramatically decreased maturation of draining lymph node dendritic cells. Therapeutic administration of recombinant activin-A during pulmonary allergen challenge suppresses Th2 responses and protects from allergic disease. Finally, we demonstrate that immune cells infiltrating the lungs from individuals with active allergic asthma, and thus nonregulated inflammatory response, exhibit significantly decreased expression of activin-A's responsive elements. Our results uncover activin-A as a novel suppressive factor for Th immunity and a critical controller of allergic airway disease

Activin-A co-opts IRF4 and AhR signaling to induce human regulatory T cells that restrain asthmatic responses

Type 1 regulatory T (Tr1) cells play a pivotal role in restraining human T-cell responses toward environmental allergens and protecting against allergic diseases. Still, the precise molecular cues that underlie their transcriptional and functional specification remain elusive. Here, we show that the cytokine activin-A instructs the generation of CD4+ T cells that express the Tr1-cell–associated molecules IL-10, inducible T-Cell costimulator (ICOS), lymphocyte activation gene 3 protein (LAG-3), and CD49b, and exert strongly suppressive functions toward allergic responses induced by naive and in vivo-primed human T helper 2 cells. Moreover, mechanistic studies reveal that activin-A signaling induces the activation of the transcription factor interferon regulatory factor (IRF4), which, along with the environmental sensor aryl hydrocarbon receptor, forms a multipartite transcriptional complex that binds in IL-10 and ICOS promoter elements and controls gene expression in human CD4+ T cells. In fact, IRF4 silencing abrogates activin-A– driven IL10 and ICOS up-regulation and impairs the suppressive functions of human activin-A–induced Tr1-like (act-A–iTr1) cells. Importantly, using a humanized mouse model of allergic asthma, we demonstrate that adoptive transfer of human act-A–iTr1 cells, both in preventive and therapeutic protocols, confers significant protection against cardinal asthma manifestations, including pulmonary inflammation. Overall, our findings uncover an activin-A–induced IRF4-aryl hydrocarbon receptor (AhR)–dependent transcriptional network, which generates suppressive human Tr1 cells that may be harnessed for the control of allergic diseases

Allergic inflammation does not impact chemical-induced carcinogenesis in the lungs of mice

<p>Abstract</p> <p>Background</p> <p>Although the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice.</p> <p>Methods</p> <p>Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment.</p> <p>Results</p> <p>Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis.</p> <p>Conclusions</p> <p>Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.</p

Cigarette smoke promotes dendritic cell accumulation in COPD; a Lung Tissue Research Consortium study

<p>Abstract</p> <p>Background</p> <p>Abnormal immune responses are believed to be highly relevant in the pathogenesis of chronic obstructive pulmonary disease (COPD). Dendritic cells provide a critical checkpoint for immunity by their capacity to both induce and suppress immunity. Although evident that cigarette smoke, the primary cause of COPD, significantly influences dendritic cell functions, little is known about the roles of dendritic cells in the pathogenesis of COPD.</p> <p>Methods</p> <p>The extent of dendritic cell infiltration in COPD tissue specimens was determined using immunohistochemical localization of CD83+ cells (marker of matured myeloid dendritic cells), and CD1a+ cells (Langerhans cells). The extent of tissue infiltration with Langerhans cells was also determined by the relative expression of the CD207 gene in COPD <it>versus </it>control tissues. To determine mechanisms by which dendritic cells accumulate in COPD, complimentary studies were conducted using monocyte-derived human dendritic cells exposed to cigarette smoke extract (CSE), and dendritic cells extracted from mice chronically exposed to cigarette smoke.</p> <p>Results</p> <p>In human COPD lung tissue, we detected a significant increase in the total number of CD83+ cells, and significantly higher amounts of CD207 mRNA when compared with control tissue. Human monocyte-derived dendritic cells exposed to CSE (0.1-2%) exhibited enhanced survival <it>in vitro </it>when compared with control dendritic cells. Murine dendritic cells extracted from mice exposed to cigarette smoke for 4 weeks, also demonstrated enhanced survival compared to dendritic cells extracted from control mice. Acute exposure of human dendritic cells to CSE induced the cellular pro-survival proteins heme-oxygenase-1 (HO-1), and B cell lymphoma leukemia-x(L) (Bcl-xL), predominantly through oxidative stress. Although activated human dendritic cells conditioned with CSE expressed diminished migratory CCR7 expression, their migration towards the CCR7 ligand CCL21 was not impaired.</p> <p>Conclusions</p> <p>These data indicate that COPD is associated with increased numbers of cells bearing markers associated with Langerhans cells and mature dendritic cells, and that cigarette smoke promotes survival signals and augments survival of dendritic cells. Although CSE suppressed dendritic cell CCR7 expression, migration towards a CCR7 ligand was not diminished, suggesting that reduced CCR7-dependent migration is unlikely to be an important mechanism for dendritic cell retention in the lungs of smokers with COPD.</p

SpeB of Streptococcus pyogenes Differentially Modulates Antibacterial and Receptor Activating Properties of Human Chemokines

BACKGROUND: CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11, are antibacterial for Streptococcus pyogenes. METHODOLOGY/PRINCIPAL FINDINGS: SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/CXCL10, I-TAC/CXCL11, PF4/CXCL4, GROalpha/CXCL1, GRObeta/CXCL2, GROgamma/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/CXCL12, BCA-1/CXCL13, BRAK/CXCL14, SRPSOX/CXCL16, MIP-3alpha/CCL20, Lymphotactin/XCL1, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/CXCL16 and MIP-3alpha/CCL20, and releases a 6 kDa CXCL9 fragment. CXCL10 and CXCL11 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity. CONCLUSIONS/SIGNIFICANCE: SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium

Glucocorticoid and Estrogen Receptors Are Reduced in Mitochondria of Lung Epithelial Cells in Asthma

Mitochondrial glucocorticoid (mtGR) and estrogen (mtER) receptors participate in the coordination of the cell’s energy requirement and in the mitochondrial oxidative phosphorylation enzyme (OXPHOS) biosynthesis, affecting reactive oxygen species (ROS) generation and induction of apoptosis. Although activation of mtGR and mtER is known to trigger anti-inflammatory signals, little information exists on the presence of these receptors in lung tissue and their role in respiratory physiology and disease. Using a mouse model of allergic airway inflammation disease and applying confocal microscopy, subcellular fractionation, and Western blot analysis we showed mitochondrial localization of GRα and ERβ in lung tissue. Allergic airway inflammation caused reduction in mtGRα, mtERβ, and OXPHOS enzyme biosynthesis in lung cells mitochondria and particularly in bronchial epithelial cells mitochondria, which was accompanied by decrease in lung mitochondrial mass and induction of apoptosis. Confirmation and validation of the reduction of the mitochondrial receptors in lung epithelial cells in human asthma was achieved by analyzing autopsies from fatal asthma cases. The presence of the mitochondrial GRα and ERβ in lung tissue cells and especially their reduction in bronchial epithelial cells during allergic airway inflammation suggests a crucial role of these receptors in the regulation of mitochondrial function in asthma, implicating their involvement in the pathophysiology of the disease

Lack of Chemokine Signaling through CXCR5 Causes Increased Mortality, Ventricular Dilatation and Deranged Matrix during Cardiac Pressure Overload

RATIONALE: Inflammatory mechanisms have been suggested to play a role in the development of heart failure (HF), but a role for chemokines is largely unknown. Based on their role in inflammation and matrix remodeling in other tissues, we hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling during HF. OBJECTIVE: We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5 in cardiac pathophysiology leading to HF. METHODS AND RESULTS: Mice harboring a systemic knockout of the CXCR5 (CXCR5(-/-)) displayed increased mortality during a follow-up of 80 days after aortic banding (AB). Following three weeks of AB, CXCR5(-/-) developed significant left ventricular (LV) dilatation compared to wild type (WT) mice. Microarray analysis revealed altered expression of several small leucine-rich proteoglycans (SLRPs) that bind to collagen and modulate fibril assembly. Protein levels of fibromodulin, decorin and lumican (all SLRPs) were significantly reduced in AB CXCR5(-/-) compared to AB WT mice. Electron microscopy revealed loosely packed extracellular matrix with individual collagen fibers and small networks of proteoglycans in AB CXCR5(-/-) mice. Addition of CXCL13 to cultured cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF, we observed increased myocardial levels of CXCR5 and SLRPs, which was reversed following LV assist device treatment. CONCLUSIONS: Lack of CXCR5 leads to LV dilatation and increased mortality during pressure overload, possibly via lack of an increase in SLRPs. This study demonstrates a critical role of the chemokine CXCL13 and CXCR5 in survival and maintaining of cardiac structure upon pressure overload, by regulating proteoglycans essential for correct collagen assembly

Epithelial-immune cell interplay in primary Sjogren syndrome salivary gland pathogenesis

In primary Sjogren syndrome (pSS), the function of the salivary glands is often considerably reduced. Multiple innate immune pathways are likely dysregulated in the salivary gland epithelium in pSS, including the nuclear factor-kappa B pathway, the inflammasome and interferon signalling. The ductal cells of the salivary gland in pSS are characteristically surrounded by a CD4(+) T cell-rich and B cell-rich infiltrate, implying a degree of communication between epithelial cells and immune cells. B cell infiltrates within the ducts can initiate the development of lymphoepithelial lesions, including basal ductal cell hyperplasia. Vice versa, the epithelium provides chronic activation signals to the glandular B cell fraction. This continuous stimulation might ultimately drive the development of mucosa-associated lymphoid tissue lymphoma. This Review discusses changes in the cells of the salivary gland epithelium in pSS (including acinar, ductal and progenitor cells), and the proposed interplay of these cells with environmental stimuli and the immune system. Current therapeutic options are insufficient to address both lymphocytic infiltration and salivary gland dysfunction. Successful rescue of salivary gland function in pSS will probably demand a multimodal therapeutic approach and an appreciation of the complicity of the salivary gland epithelium in the development of pSS. Salivary gland dysfunction is an important characteristic of primary Sjogren syndrome (pSS). In this Review, the authors discuss various epithelial abnormalities in pSS and the mechanisms by which epithelial cell-immune cell interactions contribute to disease development and progression