Project description:Background: A subset of asthmatics does not respond to steroid therapy and therefore is at risk for escalation of disease severity. The cause of corticosteroid resistant (CR) asthma is unknown. Gene microarray technologies have the potential to substantiate new hypotheses regarding the etiology of corticosteroid resistance. Methods: Gene microarray analysis was performed with bronchoalveolar lavage (BAL) cells of CR and corticosteroid sensitive (CS) asthmatics. Increased gene expression was verified with real time PCR and at the protein level by ELISA. Findings: Microarray analyses demonstrated significantly higher levels (over two-fold increase, p<0.05) of TNF-alpha, IL-1alpha, IL-1beta, IL-6, CXCL1, CXCL2, CXCL3, CXCL8 (IL-8), CCL3, CCL4, CCL20 gene expression in BAL cells of CR than CS asthmatics. These findings, confirmed by RT-PCR in additional BAL samples, were consistent with classical macrophage activation by bacterial products. In contrast, markers of alternatively-activated macrophages, Arginase I and CCL24, were decreased in CR asthmatics. Genes associated with activation of the LPS signaling pathway (EGR1, DUSP2, MAIL, TNFAIP3) were significantly elevated in CR BAL samples (p<0.05). CR asthmatics had significantly higher amounts (1444.0Â±457.3 pg per mg of total protein) of LPS in BAL fluid than CS asthmatics (270.5Â±216.0 pg; p<0.05). Prolonged exposure to LPS induced functional steroid resistance to dexamethasone (DEX) in normal monocytes, demonstrated by persistently elevated IL-6 levels in the presence of DEX. Interpretation: Classical macrophage activation and induction of LPS signaling pathways along with high endotoxin levels detected in BAL fluid from CR asthmatics suggest that LPS exposure may contribute to CR asthma. Experiment Overall Design: Patients with a diagnosis of asthma according to American Thoracic Society criteria were selected for evaluation. Asthmatics had a baseline FEV1% predicted of 55% to 85% of predicted, a beta2-adrenergic response of â¥12% of baseline FEV1% predicted and/or a methacholine PC20 value of â¤8 mg/ml. Asthma patients were further subdivided in CR and CS groups, based on their response to steroids. The definition was based on change in FEV1 % predicted over a one-week course of 40 mg/day of oral prednisone. Asthmatic patients were defined as CS if they had an increase in FEV1% predicted of greater than 15% after a one-week course of prednisone, and as CR if less than 12% change in FEV1% predicted was observed. None of the asthmatic subjects recruited for this study had evidence for other types of lung diseases. None of the subjects had received systemic corticosteroid therapy for at least one month prior to bronchoscopy. All subjects provided written informed consent to participate in the study. The study was approved by the Institutional Review Board at National Jewish Medical and Research Center, Denver, CO. Gene array studies of BAL macrophages were performed in 3 CR and 3 CS asthmatics.

Project description:Clubroot of Brassicaceae, an economically important soil borne disease, is caused by Plasmodiophora brassicae Woronin, an obligate, biotrophic protist. This disease poses a serious threat to canola and related crops in Canada and around the globe causing significant loss to seed yield. The pathogen is continuously evolving and new pathotypes are emerging, this necessitates the development of novel resistant canola cultivars to manage the disease effectively. Given that proteins play a crucial role in majority of biological processes and molecular functions, the identification of differentially abundant proteins (DAP) using proteomics information is an attractive approach to understand the plant-pathogen interactions as well as in the future development of gene specific markers for developing clubroot resistant (CR) cultivars. In this study, P. brassicae pathotype 3 (P3H) was used to challenge CR and clubroot susceptible (CS) canola lines. Root samples were collected at three distinct stages of pathogenesis, 7-, 14-, and 21-days post inoculation (DPI), protein samples were isolated, digested with trypsin and subjected to LC-MS/MS analysis. A total of 937 proteins demonstrated a significant (q < 0.05) change in abundance in at least in one of the time points when compared between control and inoculated CR-parent, CR-progeny, CS-parent, CS-progeny and 784 proteins were significantly (q < 0.05) changed in abundance in at least in one of the time points when compared between the inoculated- CR and CS root proteomes of parent and progeny across the three time points tested. Functional annotation of the differentially abundant proteins (DAPs) revealed several proteins related to calcium dependent signaling pathways in response to the pathogen. In addition, proteins related to reactive oxygen species (ROS) biochemistry, dehydrins, lignin, thaumatin, and phytohormones were identified. Among the DAPs, 74 putative proteins orthologous to CR proteins and quantitative trait loci (QTL) associated with eight CR loci in four chromosomes including chromosomes A3 and A8 were identified. In conclusion, these results have contributed to an improved understanding of the mechanisms that are involved in mediating response to P. brassicae in canola at the protein level.

Project description:Patients with severe uncontrolled asthma represent a distinct endotype with persistent airway inflammation and remodeling refractory to corticosteroid treatment. CD4+ T cells and their canonical effector molecules, like type 2 cytokines, play a central role in orchestrating asthma pathogenesis, and biologic therapies targeting these cytokine pathways have had promising outcomes. However, not all patients respond well to such treatment, and their effects are not always durable nor reverse airway remodeling. This observation raises the possibility that other CD4+ T cell subsets and their effector molecules may drive airway inflammation and remodeling. To address this issue in a hypothesis-free manner, we performed single-cell transcriptome analysis of >50,000 airway CD4+ T cells isolated from bronchoalveolar lavage (BAL) samples from 30 patients with mild and severe asthma. We observed striking heterogeneity in the nature of CD4+ T cells present in asthmatics' airways with tissue-resident memory (TRM) cells making a dominant contribution. Notably, a subset of CD4+ TRM cells (CD103-expressing) was significantly increased, comprising nearly 65% of all CD4+ T cells in the airways of male patients with severe asthma when compared to mild asthma. This subset was enriched for transcripts linked to T cell receptor (TCR) activation (HLA-DRB1, HLA-DPA1, CD40LG) and cytotoxicity (GZMB, GZMH), and following stimulation expressed high levels of transcripts encoding for pro-inflammatory non-TH2 cytokines (CCL3, CCL4, CCL5, TNF, IL-17A, CSF2, LIGHT) that could fuel persistent airway inflammation and remodeling. Furthermore, we found that CD4+ T cells isolated ex vivo from airways of severe asthmatics displayed signatures linked to corticosteroid resistance (FKBP5, DDIT4), as well as reduced expression of transcripts encoding for molecules that dampen TCR signaling and T cell effector functions (CREM, DUSP1, TNFAIP3). Overall, our single-cell transcriptomic analysis highlights the pathogenic properties and clinical associations of airway CD4+ T cell subsets in severe asthmatics, features that can potentially trigger their unrestrained activation, and that these findings were more pronounced in males. These pathways may therefore be crucial for driving disease severity in adult male severe asthmatics.

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Corticosteroid Resistant Asthma Is Associated with Classical Activation Of Airway Macrophages and Exposure To LPS

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