Project description:Obesity-associated asthma is recognized as a distinct entity with non-atopic T-helper 1 polarized systemic inflammation. DNA methylation is linked with T helper cell maturation and is associated with inflammatory patterns in asthma and obesity. However, it is unknown whether pathologic dysregulation of DNA methylation patterns occurs in obesity-associated asthma. Using HELP-tagging, we studied epigenome wide DNA methylation in peripheral blood mononuclear cells in 8 urban minority obese asthmatic pre-adolescent children and compared it to methylation in groups of 8 children with asthma alone, obesity alone and healthy controls. Ingenuity Pathway Analysis was used to identify biological pathways that were differentially targeted by methylation dysregulation. We found that obese asthmatics had distinct epigenome wide methylation patterns associated with decreased promoter methylation of a subset of genes, including RANTES, IL-12R and TBX21 and increased promoter methylation of CD23, a low affinity receptor for IgE and of TGFM-NM-2, inhibitor of Th cell activation. T cell signaling and macrophage activation were the two primary pathways that were selectively hypomethylated in obese asthmatics. These methylation patterns suggest that methylation is associated with non-atopic inflammation observed in obese asthmatic children compared to children with asthma alone and obesity alone. Our findings suggest a role of DNA methylation in the observed inflammatory patterns in pediatric obesity-associated asthma in minorities. 32 HpaII test
Project description:Obesity-associated asthma is recognized as a distinct entity with non-atopic T-helper 1 polarized systemic inflammation. DNA methylation is linked with T helper cell maturation and is associated with inflammatory patterns in asthma and obesity. However, it is unknown whether pathologic dysregulation of DNA methylation patterns occurs in obesity-associated asthma. Using HELP-tagging, we studied epigenome wide DNA methylation in peripheral blood mononuclear cells in 8 urban minority obese asthmatic pre-adolescent children and compared it to methylation in groups of 8 children with asthma alone, obesity alone and healthy controls. Ingenuity Pathway Analysis was used to identify biological pathways that were differentially targeted by methylation dysregulation. We found that obese asthmatics had distinct epigenome wide methylation patterns associated with decreased promoter methylation of a subset of genes, including RANTES, IL-12R and TBX21 and increased promoter methylation of CD23, a low affinity receptor for IgE and of TGFβ, inhibitor of Th cell activation. T cell signaling and macrophage activation were the two primary pathways that were selectively hypomethylated in obese asthmatics. These methylation patterns suggest that methylation is associated with non-atopic inflammation observed in obese asthmatic children compared to children with asthma alone and obesity alone. Our findings suggest a role of DNA methylation in the observed inflammatory patterns in pediatric obesity-associated asthma in minorities.
Project description:Different naïve or memory cell subpopulations (i.e., central memory/CM, effector memory/EM, or terminally differentiated effector memory/EMRA) are involved in asthma development, and they display variable levels of the CD26 (dipeptidyl peptidase 4/DPP4). The phenotype and/or severity of the disease could drive to a phenotypic shift in naïve/memory lymphocyte subsets. Therefore, the aim of our work was to evaluate the association of the phenotype and severity of asthma with the relative frequency of CD26-/lo, CD26int, and CD26hi subsets within CD4+ effector T cells (Teff), total CD4- lymphocytes, γδ-T cells, NK cells, and NKT cells. For that, flow cytometry analyses were performed in peripheral blood samples from healthy donors (N=30) and asthma patients (N=119) with different phenotypes/severities. To avoid a priori bias, we have performed a K-means clustering analysis including clinical and flow cytometry data, resulting in four groups, two of them with opposite inflammatory profiles (eosinophilic vs. neutrophilic). CD4-CD26hi cells were reduced in neutrophilic asthma, and negatively correlated with degree of systemic inflammation. Interestingly, the eosinophilic group displayed a general expansion of CD26-/lo lymphocyte subsets. The expansion of CD4+CD26-/lo Teff cells with a TEM/TEMRA phenotype was confirmed in asthma, especially in atopic patients. Further characterisation of this subset by LC MS/MS revealed upregulated levels of innate (e.g., MPO and RNASE2) and cytoskeleton/extracellular matrix (e.g., MMP9, ACTN1) proteins, which matches its terminally differentiated phenotype. Validation by immunofluorescence confirmed the presence of many of these proteins in CD4+ T cells, as well as an enrichment in “flower-like” nuclei and MMP9/RNASE2 levels in CD4+CD26-/lo Teff compared to CD4+ T lymphocytes. Therefore, there is an association between CD26 levels in different lymphocyte subsets and asthma phenotypes/severities. CD4+CD26-/loTEMRA cells expressing innate proteins specific to eosinophils/neutrophils could be relevant in sustaining long-term inflammation in adult allergic asthma.
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.
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.