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David J Erle

Publications and source records attributed to David J Erle.

15 recordsLinked to original sources
PubMed2025

High-affinity CD16A polymorphism associated with reduced risk ofsevere COVID-19.

CD16A is an activating Fc receptor on NK cells that mediates antibody-dependent cellular cytotoxicity (ADCC), a key mechanism in antiviral immunity. However, the role of NK cell-mediated ADCC in SARS-CoV-2 infection remains unclear, particularly whether it limits viral spread and disease severity or contributes to the immunopathogenesis of COVID-19. We hypothesized that the high-affinity CD16AV176 polymorphism influences these outcomes. Using an in vitro reporter system, we demonstrated that CD16AV176 is a more potent and sensitive activator than the common CD16AF176 allele. To assess its clinical relevance, we analyzed 1,027 patients hospitalized with COVID-19 from the Immunophenotyping Assessment in a COVID-19 cohort (IMPACC), a comprehensive longitudinal dataset with extensive transcriptomic, proteomic, and clinical data. The high-affinity CD16AV176 allele was associated with a significantly reduced risk of ICU admission, mechanical ventilation, and severe disease trajectories. Lower anti-SARS-CoV-2 IgG titers were correlated to CD16AV176; however, there was no difference in viral load across CD16A genotypes. Proteomic analysis revealed that participants homozygous for CD16AV176 had lower levels of inflammatory mediators. These findings suggest that CD16AV176 enhances early NK cell-mediated immune responses, limiting severe respiratory complications in COVID-19. This study identifies a protective genetic factor against severe COVID-19, informing future host-directed therapeutic strategies.

Humans↗
PubMed2006

IL-13 and epidermal growth factor receptor have critical but distinct roles in epithelial cell mucin production.

Overproduction of mucus is a central feature of asthma. The cytokine, IL-13, epidermal growth factor receptor (EGFR), and transcription factor, FOXA2, have each been implicated in mucus production, but the mechanistic relationships between these molecules are not yet well understood. To address this, we established a primary normal human bronchial epithelial cell culture system with IL-13-induced mucus production and gene transcript expression changes similar to those seen in vivo in mice. IL-13 did not stimulate release of the EGFR ligand, transforming growth factor (TGF)-alpha. However, there was constitutive release of TGF-alpha from normal human bronchial epithelial cells, and inhibition of TGF-alpha or EGFR reduced both constitutive and IL-13-induced mucin production. Microarray analysis revealed that IL-13 and the EGFR pathway appear to have almost completely independent effects on transcript expression. IL-13 induced a relatively small set of transcripts, including several novel transcripts that might play a role in pathogenesis of allergic airway disease. In contrast, EGFR activity had extensive effects, including altered expression of many transcripts associated with cell metabolism, survival, transcription, and differentiation. One of the few common effects of IL-13 and EGFR signaling was decreased expression of FOXA2, which is known to prevent mucus production. We conclude that the IL-13 and EGFR pathways make critical but quite distinct contributions to gene regulation in airway epithelial cells, and that both pathways affect expression of the key transcription factor, FOXA2, a known regulator of mucus production.

Administration, Intranasal↗
PubMed2005

A distinctive alveolar macrophage activation state induced by cigarette smoking.

RATIONALE: Macrophages are believed to play a central role in emphysema based largely on data from mouse models. However, the relevance of these models to smoking-related lung disease in humans is uncertain. OBJECTIVES: We sought to comprehensively characterize the effects of smoking on gene expression in human alveolar macrophages and to compare these with effects seen in transgenic mouse models of emphysema. METHODS: We used DNA microarrays with genomewide coverage to analyze alveolar macrophages from 15 smokers, 15 nonsmokers, and 15 subjects with asthma (disease control). Selected gene expression changes were validated by polymerase chain reaction and ELISA. Expression changes were compared with those identified by microarray analysis of interleukin-13-overexpressing and integrin-beta6-deficient mice, which both develop emphysema. MEASUREMENTS AND MAIN RESULTS: All 15 smokers shared a common pattern of macrophage gene expression that distinguished them from nonsmokers, a finding not observed in subjects with asthma. We identified 110 genes as differentially expressed in smokers despite using conservative statistical methods. Matrix metalloproteinase 12, a proteinase that plays a critical role in mouse models, was the third most highly induced gene in smokers (ninefold, p < 0.0001). However, most changes in smokers were not reflected in mouse models. One such finding was increased osteopontin expression in smokers (fourfold, p = 0.006), which was confirmed at the protein level and correlated with the degree of airway obstruction. CONCLUSIONS: Smoking induces a remarkably consistent and distinctive pattern of alveolar macrophage activation. These studies identify aspects of mouse models that are directly relevant to human smokers and also reveal novel potential mediators of smoking-related diseases.

Adult↗
PubMed2005

IL-4 receptor signaling in Clara cells is required for allergen-induced mucus production.

Excessive mucus production is an important pathological feature of asthma. The Th2 cytokines IL-4 and IL-13 have both been implicated in allergen-induced mucus production, inflammation, and airway hyperreactivity. Both of these cytokines use receptors that contain the IL-4Ralpha subunit, and these receptors are expressed on many cell types in the lung. It has been difficult to determine whether allergen-induced mucus production is strictly dependent on direct effects of IL-4 and IL-13 on epithelial cells or whether other independent mechanisms exist. To address this question, we used a cell type-specific inducible gene-targeting strategy to selectively disrupt the IL-4Ralpha gene in Clara cells, an airway epithelial cell population that gives rise to mucus-producing goblet cells. Clara cell-specific IL-4Ralpha-deficient mice and control mice developed similar elevations in serum IgE levels, airway inflammatory cell numbers, Th2 cytokine production, and airway reactivity following OVA sensitization and challenge. However, compared with control mice, Clara cell-specific IL-4Ralpha-deficient mice were nearly completely protected from allergen-induced mucus production. Because only IL-13 and IL-4 are thought to signal via IL-4Ralpha, we conclude that direct effects of IL-4 and/or IL-13 on Clara cells are required for allergen-induced mucus production in the airway epithelium.

Allergens↗
PubMed2005

Increased DNA microarray hybridization specificity using sscDNA targets.

BACKGROUND: The most widely used amplification method for microarray analysis of gene expression uses T7 RNA polymerase-driven in vitro transcription (IVT) to produce complementary RNA (cRNA) that can be hybridized to arrays. However, multiple rounds of amplification are required when assaying very small amounts of starting RNA. Moreover, certain cRNA-DNA mismatches are more stable than the analogous cDNA-DNA mismatches and this might increase non-specific hybridization. We sought to determine whether a recently developed linear isothermal amplification method (ribo-SPIA) that produces single stranded cDNA would offer advantages over traditional IVT-based methods for microarray-based analyses of transcript expression. RESULTS: A single round of ribo-SPIA amplification produced sufficient sscDNA for hybridizations when as little as 5 ng of starting total RNA was used. Comparisons of probe set signal intensities obtained from replicate amplifications showed consistently high correlations (r = 0.99). We compared gene expression in two different human RNA samples using ribo-SPIA. Compared with one round IVT, ribo-SPIA had a larger dynamic range and correlated better with quantitative PCR results even though we used 1000-fold less starting RNA. The improved dynamic range was associated with decreases in hybridization to mismatch control probes. CONCLUSION: The use of amplified sscDNA may offer substantial advantages over IVT-based amplification methods, especially when very limited amounts of starting RNA are available. The use of sscDNA targets instead of cRNA targets appears to improve hybridization specificity.

Animals↗
PubMed2005

Dissecting asthma using focused transgenic modeling and functional genomics.

BACKGROUND: Asthma functional genomics studies are challenging because it is difficult to relate gene expression changes to specific disease mechanisms or pathophysiologic features. Use of simplified model systems might help to address this problem. One such model is the IL-13/Epi (IL-13-overexpressing transgenic mice with STAT6 expression limited to epithelial cells) focused transgenic mouse, which isolates the effects of a single mediator, IL-13, on a single cell type, the airway epithelial cell. These mice develop airway hyperreactivity and mucus overproduction but not airway inflammation. OBJECTIVE: To identify how effects of IL-13 on airway epithelial cells contribute to gene expression changes in murine asthma models and determine whether similar changes are seen in people with asthma. METHODS: We analyzed gene expression in ovalbumin allergic mice, IL-13-overexpressing mice, and IL-13/Epi mice with microarrays. We analyzed the expression of human orthologues of genes identified in the mouse studies in airway epithelial cells from subjects with asthma and control subjects. RESULTS: In comparison with the other 2 models, IL-13/Epi mice had a remarkably small subset of gene expression changes. Human orthologues of some genes identified as increased in the mouse models were more highly expressed in airway epithelial cells from subjects with asthma than in controls. These included calcium-activated chloride channel 1, 15-lipoxygenase, trefoil factor 2, and intelectin. CONCLUSION: The combination of focused transgenic models, DNA microarray analyses, and translational studies provides a powerful approach for analyzing the contributions of specific mediators and cell types and for focusing attention on a limited number of genes associated with specific pathophysiologic aspects of asthma.

Animals↗
PubMed2004

Aspergillus antigen induces robust Th2 cytokine production, inflammation, airway hyperreactivity and fibrosis in the absence of MCP-1 or CCR2.

BACKGROUND: Asthma is characterized by type 2 T-helper cell (Th2) inflammation, goblet cell hyperplasia, airway hyperreactivity, and airway fibrosis. Monocyte chemoattractant protein-1 (MCP-1 or CCL2) and its receptor, CCR2, have been shown to play important roles in the development of Th2 inflammation. CCR2-deficient mice have been found to have altered inflammatory and physiologic responses in some models of experimental allergic asthma, but the role of CCR2 in contributing to inflammation and airway hyperreactivity appears to vary considerably between models. Furthermore, MCP-1-deficient mice have not previously been studied in models of experimental allergic asthma. METHODS: To test whether MCP-1 and CCR2 are each required for the development of experimental allergic asthma, we applied an Aspergillus antigen-induced model of Th2 cytokine-driven allergic asthma associated with airway fibrosis to mice deficient in either MCP-1 or CCR2. Previous studies with live Aspergillus conidia instilled into the lung revealed that MCP-1 and CCR2 play a role in anti-fungal responses; in contrast, we used a non-viable Aspergillus antigen preparation known to induce a robust eosinophilic inflammatory response. RESULTS: We found that wild-type C57BL/6 mice developed eosinophilic airway inflammation, goblet cell hyperplasia, airway hyperreactivity, elevations in serum IgE, and airway fibrosis in response to airway challenge with Aspergillus antigen. Surprisingly, mice deficient in either MCP-1 or CCR2 had responses to Aspergillus antigen similar to those seen in wild-type mice, including production of Th2 cytokines. CONCLUSION: We conclude that robust Th2-mediated lung pathology can occur even in the complete absence of MCP-1 or CCR2.

Animals↗
PubMed2004

Differential gene expression by integrin beta 7+ and beta 7- memory T helper cells.

BACKGROUND: The cell adhesion molecule integrin alpha 4 beta 7 helps direct the migration of blood lymphocytes to the intestine and associated lymphoid tissues. We hypothesized that beta 7+ and beta 7- blood memory T helper cells differ in their expression of genes that play a role in the adhesion or migration of T cells. RESULTS: RNA was prepared from beta 7+ and beta 7- CD4+ CD45RA- blood T cells from nine normal human subjects and analyzed using oligonucleotide microarrays. Of 21357 genes represented on the arrays, 16 were more highly expressed in beta 7+ cells and 18 were more highly expressed in beta 7- cells (>/=1.5 fold difference and adjusted P < 0.05). Several of the differentially expressed transcripts encode proteins with established or putative roles in lymphocyte adhesion and chemotaxis, including the chemokine receptors CCR9 and CCR10, the integrin alpha 4 subunit, L-selectin, KLRB1 (CD161), NT5E (CD73), LGALS1 and LGALS2 (galectin-1 and -2), and RGS1. Flow cytometry was used to determine whether differences in levels of transcripts encoding cell surface proteins were associated with differential expression of those proteins. Using this approach, we found that surface expression of KLRB1, LAIR1, and NT5E proteins was higher on beta 7+ memory/effector T cells than on beta 7- cells. CONCLUSIONS: Memory/effector T cells that express integrin beta 7 have a distinct pattern of expression of a set of gene transcripts. Several of these molecules can affect cell adhesion or chemotaxis and are therefore likely to modulate the complex multistep process that regulates trafficking of CD4+ memory T cell subsets with different homing behaviors.

Adult↗
PubMed2003

Abnormal alveolar development associated with elevated adenine nucleosides.

Adenosine signaling has been characterized in various physiologic systems, but little is known about the role of adenosine signaling in lung development. Alveogenesis and microvascular maturation are the final stages in lung development in mammals. Alveogenesis in the mouse begins on Postnatal Day 5, when the process of secondary septation plays a pivotal role in the expansion of the alveolar sacs and microvascular maturation. Adenosine deaminase null mice (ADA-/-) exhibit abnormalities in alveogenesis in association with elevated lung adenosine levels. Large-scale gene expression analysis of ADA-/- lungs using oligonucleotide-based microarrays revealed novel relationships between gene expression patterns and elevated lung adenosine during the stages of alveolar maturation. Genes regulating apoptosis, proliferation, and vascular development were shown to be altered, and decreased cell proliferation in association with increased alveolar type II cell apoptosis was shown to contribute to abnormal secondary septation in these mice. ADA enzyme therapy allowed for normal patterns of apoptosis, proliferation, and alveolar development in association with prevention of adenosine elevations. These findings were correlated with the presence of adenosine receptors in the developing lung, suggesting the involvement of receptor signaling. These studies provide evidence that elevated lung adenosine can lead to abnormal alveogenesis by disrupting patterns of cell proliferation and apoptosis.

Adenine Nucleotides↗
PubMed2003

Spotted long oligonucleotide arrays for human gene expression analysis.

DNA microarrays produced by deposition (or 'spotting')of a single long oligonucleotide probe for each gene may be an attractive alternative to other types of arrays. We produced spotted oligonucleotide arrays using two large collections of approximately 70-mer probes, and used these arrays to analyze gene expression in two dissimilar human RNA samples. These samples were also analyzed using arrays produced by in situ synthesis of sets of multiple short (25-mer) oligonucleotides for each gene (Affymetrix GeneChips). We compared expression measurements for 7344 genes that were represented in both long oligonucleotide probe collections and the in situ-synthesized 25-mer arrays. We found strong correlations (r = 0.8-0.9) between relative gene expression measurements made with spotted long oligonucleotide probes and in situ-synthesized 25-mer probe sets. Spotted long oligonucleotide arrays were suitable for use with both unamplified cDNA and amplified RNA targets, and are a cost-effective alternative for many functional genomics applications. Most previously reported evaluations of microarray technologies have focused on expression measurements made on a relatively small number of genes. The approach described here involves far more gene expression measurements and provides a useful method for comparing existing and emerging techniques for genome-scale expression analysis.

Cell Line↗
PubMed2002

Direct effects of interleukin-13 on epithelial cells cause airway hyperreactivity and mucus overproduction in asthma.

Asthma is an increasingly common disease that remains poorly understood and difficult to manage. This disease is characterized by airway hyperreactivity (AHR, defined by exaggerated airflow obstruction in response to bronchoconstrictors), mucus overproduction and chronic eosinophilic inflammation. AHR and mucus overproduction are consistently linked to asthma symptoms and morbidity. Asthma is mediated by Th2 lymphocytes, which produce a limited repertoire of cytokines, including interleukin-4 (IL-4), IL-5, IL-9 and IL-13. Although each of these cytokines has been implicated in asthma, IL-13 is now thought to be especially critical. In animal models of allergic asthma, blockade of IL-13 markedly inhibits allergen-induced AHR, mucus production and eosinophilia. Furthermore, IL-13 delivery to the airway causes all of these effects. IL-13 is thus both necessary and sufficient for experimental models of asthma. However, the IL-13-responsive cells causing these effects have not been identified. Here we show that mice lacking signal transducer and activator of transcription 6 (STAT6) were protected from all pulmonary effects of IL-13. Reconstitution of STAT6 only in epithelial cells was sufficient for IL-13-induced AHR and mucus production in the absence of inflammation, fibrosis or other lung pathology. These results demonstrate the importance of direct effects of IL-13 on epithelial cells in causing two central features of asthma.

Animals↗
PubMed2002

The Th2 lymphocyte products IL-4 and IL-13 rapidly induce airway hyperresponsiveness through direct effects on resident airway cells.

Airway inflammation and airway hyperresponsiveness (AHR) are hallmarks of asthma. Cytokines produced by T helper type 2 (Th2) lymphocytes have been implicated in both processes. There is strong support for the idea that Th2 cytokines can produce AHR indirectly by promoting the recruitment of inflammatory cells. Less attention has been given to the possibility that Th2 cytokines might induce AHR by acting directly on resident airway cells. To investigate this, we polarized and activated CD4(+) T cells in vitro and analyzed airway function after administration of lymphocyte-conditioned media to the airways of naive mice. Th2-lymphocyte-conditioned medium induced AHR within 6 h. This finding was reproduced in mast-cell-deficient and in T- and B-lymphocyte-deficient mice. AHR did not occur when Th2-lymphocyte-conditioned medium was administered to mice lacking the IL-4 receptor alpha subunit or Stat6, suggesting a critical role for interleukin (IL)-4 and/or IL-13. This was confirmed by the finding that recombinant IL-4 and IL-13 both induced AHR within 6 h. The induction of AHR occurred in the absence of inflammatory cell recruitment or mucus production. These results strongly suggest that products of activated Th2 lymphocytes can rapidly perturb airway function through direct effects on resident airway cells.

Animals↗