Project description:Asthma, a common disorder that affects >250 million people worldwide, is defined by exaggerated bronchoconstriction to inflammatory mediators including acetylcholine (ACh), bradykinin and histamine-also termed airway hyper-responsiveness. Nearly 10% of people with asthma have severe, treatment-resistant disease, which is frequently associated with immunoglobulin-E sensitization to ubiquitous fungi, typically Aspergillus fumigatus (Af). Here we show that a major Af allergen, Asp f13, which is a serine protease, alkaline protease 1 (Alp 1), promotes airway hyper-responsiveness by infiltrating the bronchial submucosa and disrupting airway smooth muscle (ASM) cell-extracellular matrix (ECM) interactions. Alp 1-mediated ECM degradation evokes pathophysiological RhoA-dependent Ca(2+) sensitivity and bronchoconstriction. These findings support a pathogenic mechanism in asthma and other lung diseases associated with epithelial barrier impairment, whereby ASM cells respond directly to inhaled environmental allergens to generate airway hyper-responsiveness.
Project description:IntroductionCeramide is the central substrate of sphingolipid metabolism and plays a key role in cellular signal transduction pathways, regulating apoptosis, differentiation, and chemotaxis. Alterations in airway ceramide levels are observed in multiple pulmonary diseases and recent human genetic association studies have linked dysregulation of sphingolipid regulatory genes with asthma pathogenesis.MethodsUtilizing myriocin, a potent inhibitor of sphingolipid synthesis, we evaluated the immune regulatory role of de novo ceramide generation in vitro and in vivo. Intratracheal myriocin was administered alone or during house dust mite sensitization (HDM) of BALB/C mice and airway hyper-responsiveness (AHR) was evaluated by invasive plethysmography followed by bronchial lavage (BAL) cytology and cytokine quantification.ResultsMyriocin inhibits and HDM exposure activates de novo ceramide synthesis in bone marrow-derived dendritic cells. Mice receiving intratracheal myriocin developed a mild airway neutrophilic infiltrate without inducing a significant increase in AHR. CXCL1 was elevated in the BAL fluid of myriocin-treated mice while the neutrophilic chemotactic factors anaphylatoxin C5a, leukotriene B4, and IL-17 were unaffected. HDM treatment combined with myriocin led to a dramatic enhancement of AHR (63% increase over HDM alone, p < 0.001) and increased granulocyte pulmonary infiltrates versus HDM or myriocin alone. Elevated Th2 T cell counts and Th2 cytokines/chemokines (IL5, IL13, CCL17) were observed in mice treated with combined HDM/myriocin compared to HDM alone. Myriocin-treated pulmonary CD11c+ cells stimulated with HDM secreted significantly more CXCL1 than cells stimulated with HDM alone while HDM stimulated airway epithelial cells showed no change in CXCL1 secretion following myriocin treatment.ConclusionsIntratracheal myriocin, likely acting via ceramide synthesis inhibition, enhances allergen-induced airway inflammation, granulocyte and Th2 lymphocyte recruitment, and allergen-induced AHR. Sphingolipid pathways may represent novel targets for possible future anti-inflammatory asthma medications.
Project description:Children who are exposed to environmental respiratory insults often develop asthma that persists into adulthood. In this study, we used a neonatal mouse model of ovalbumin (OVA)-induced allergic airway inflammation to understand the long-term effects of early childhood insults on airway structure and function. We showed that OVA sensitization and challenge in early life led to a 2-fold increase in airway smooth muscle (ASM) innervation (P<0.05) and persistent airway hyperreactivity (AHR). In contrast, OVA exposure in adult life elicited short-term AHR without affecting innervation levels. We found that postnatal ASM innervation required neurotrophin (NT)-4 signaling through the TrkB receptor and that early-life OVA exposure significantly elevated NT4 levels and TrkB signaling by 5- and 2-fold, respectively, to increase innervation. Notably, blockade of NT4/TrkB signaling in OVA-exposed pups prevented both acute and persistent AHR without affecting baseline airway function or inflammation. Furthermore, biophysical assays using lung slices and isolated cells demonstrated that NT4 was necessary for hyperreactivity of ASM induced by early-life OVA exposure. Together, our findings show that the NT4/TrkB-dependent increase in innervation plays a critical role in the alteration of the ASM phenotype during postnatal growth, thereby linking early-life allergen exposure to persistent airway dysfunction.
Project description:BackgroundAllergen-specific immunotherapy has been demonstrated to have potential for the treatment of allergic diseases. Transgenic animals are currently the best available bioreactors to produce recombinant proteins, which can be secreted in milk. It has not been clearly demonstrated whether milk from transgenic animals expressing recombinant allergens has immunomodulatory effects on allergic asthma.MethodsWe aimed to determine whether the oral administration of milk containing a mite allergen can down-regulate allergen-specific airway inflammation. Transgenic CD-1 mice that express a recombinant group 2 allergen from Dermatophagoides pteronyssinus (Dp2) in their milk were generated using an embryonic gene-microinjection technique. Mouse pups were fed transgenic Dp2-containing milk or wild-type milk. Subsequently, these mice were sensitized and challenged with Dp2 to induce allergic airway inflammation.ResultsUpon sensitization and challenge, mice fed transgenic Dp2 milk had decreased T-helper 2 (Th2) and increased T-helper 1 (Th1) responses in the airway compared with mice fed wild-type milk. Moreover, pre-treatment with transgenic Dp2 milk attenuated airway inflammation and decreased airway hyper-responsiveness.ConclusionsThis study provides new evidence that oral administration of transgenic milk containing the Dp2 allergen down-regulated and moderately protected against allergic airway inflammation. Milk from transgenic animals expressing allergens may have potential use in the prevention of allergic asthma.
Project description:Radio frequency (RF) technique, for its better penetrability over traditional techniques such as infrared or ultrasound, is widely used for indoor localization and tracking. In this paper, three novel measurements, point decision accuracy, path matching error and wrong jumping ratio, are firstly defined to express the localization efficiency. Then, a novel RSSI-based smooth localization (RSL) algorithm is designed, implemented, and evaluated on the WiFi networks. The tree-based mechanism determines the current position and track of the entity by assigning the weights and accumulative weights for all collected RSSI information of reference points so as to make the localization smooth. The evaluation results indicate that the proposed algorithm brings better localization smoothness of reducing 10% path matching error and 30% wrong jumping ratio over the RADAR system.
Project description:In animals and humans, offspring of allergic mothers have increased responsiveness to allergen and the allergen-specificity of the offspring can be different than that of the mother. In our preclinical models, the mother's allergic responses influence development of the fetus and offspring by elevating numbers of cells in dendritic cell subsets. A major question is the identity of maternal factors of allergic mothers that alter offspring development of responsiveness to allergen. Lipids are altered during allergic responses and lipids are transported to the fetus for growth and formation of fetal membranes. We hypothesized that pro-inflammatory lipids, that are elevated in allergic mothers, are transported to the fetus and regulate fetal immune development. We demonstrate in this report that there was a significant 2-fold increase in β-glucosylceramides (βGlcCer) in allergic mothers, the fetal liver and her offspring. The βGlcCer were transported from mother's plasma, across the placenta, to the fetus and in breastmilk to the offspring. Administration of βGlcCer to non-allergic mothers was sufficient for offspring responses to allergen. Importantly, maternal administration of a clinically relevant pharmacological inhibitor of βGlcCer synthase returned βGlcCer to normal levels in the allergic mothers and her offspring and blocked the offspring increase in dendritic cell subsets and offspring allergen responsiveness. In summary, allergic mothers had increased βGlcCer that was transported to offspring and mediated increases in offspring DCs and responsiveness to allergen. These data have a significant impact on our understanding of mechanisms for development of allergies in offspring of allergic mothers and have the potential to lead to novel interventions that significantly impact risk for allergic disease early in life.
Project description:Hyaluronan (HA), a major component of the extracellular matrix, is secreted by airway structural cells. Airway fibroblasts in allergic asthma secrete elevated levels of HA in association with increased HA synthase 2 (HAS2) expression. Thus, we hypothesized that HA accumulation in the airway wall may contribute to airway remodeling and hyperresponsiveness in allergic airways disease. To examine this hypothesis, transgenic mice in which the ?-smooth muscle actin (?-SMA) promoter drives HAS2 expression were generated. Mixed male and female ?-SMA-HAS2 mice (HAS2+ mice, n?=?16; HAS2- mice, n?=?13) were sensitized via intraperitoneal injection and then chronically challenged with aerosolized ovalbumin (OVA) for 6 weeks. To test airway responsiveness, increasing doses of methacholine were delivered intravenously and airway resistance was measured using the forced oscillation technique. HA, cytokines, and cell types were analyzed in bronchoalveolar lavage fluid, serum, and whole lung homogenates. Lung sections were stained using antibodies specific for HA-binding protein (HABP) and ?-SMA, as well as Masson's trichrome stain. Staining of lung tissue demonstrated significantly increased peribronchial HA, ?-SMA, and collagen deposition in OVA-challenged ?-SMA-HAS2+ mice compared with ?-SMA-HAS2- mice. Unexpectedly, OVA-challenged ?-SMA-HAS2+ mice displayed significantly reduced airway responsiveness to methacholine compared with similarly treated ?-SMA-HAS2- mice. The total numbers of inflammatory cell types in the bronchoalveolar lavage fluid did not differ significantly between OVA-challenged ?-SMA-HAS2+ mice and ?-SMA-HAS2- mice. We conclude that allergen-challenged mice that overexpress HAS2 in myofibroblasts and smooth muscle cells develop increased airway fibrosis, which lessens airway hyperresponsiveness to bronchoconstrictors.