Project description:Selective stimulation of IL-4 receptor on smooth muscle induces airway hyper-responsiveness in mice. Abstract: Production of the cytokines IL-4 and IL-13 is increased in both human asthma and mouse asthma models and Stat6 activation by the common IL-4/IL-13R drives most mouse model pathophysiology, including airway hyperresponsiveness (AHR). However, the precise cellular mechanisms through which IL-4Rα induces AHR remain unclear. Overzealous bronchial smooth muscle constriction is thought to underlie AHR in human asthma, but the smooth muscle contribution to AHR has never been directly assessed. Furthermore, differences in mouse vs. human airway anatomy and observations that selective IL-13 stimulation of Stat6 in airway epithelium induces murine AHR raise questions about the importance of direct IL-4R effects on smooth muscle in murine asthma models and relevance of these models to human asthma. Using transgenic mice in which smooth muscle is the only cell type that expresses or fails to express IL-4Rα, we demonstrate that direct smooth muscle activation by IL-4, IL-13, or allergen is sufficient, but not necessary, to induce AHR and show that 5 genes known to promote smooth muscle migration, proliferation and contractility are activated by IL-13 in smooth muscle in vivo. These observations demonstrate that IL-4Rα promotes AHR through multiple mechanisms and provide a model for testing smooth muscle-directed asthma therapeutics.
Project description:Selective stimulation of IL-4 receptor on smooth muscle induces airway hyper-responsiveness in mice. Abstract: Production of the cytokines IL-4 and IL-13 is increased in both human asthma and mouse asthma models and Stat6 activation by the common IL-4/IL-13R drives most mouse model pathophysiology, including airway hyperresponsiveness (AHR). However, the precise cellular mechanisms through which IL-4Rα induces AHR remain unclear. Overzealous bronchial smooth muscle constriction is thought to underlie AHR in human asthma, but the smooth muscle contribution to AHR has never been directly assessed. Furthermore, differences in mouse vs. human airway anatomy and observations that selective IL-13 stimulation of Stat6 in airway epithelium induces murine AHR raise questions about the importance of direct IL-4R effects on smooth muscle in murine asthma models and relevance of these models to human asthma. Using transgenic mice in which smooth muscle is the only cell type that expresses or fails to express IL-4Rα, we demonstrate that direct smooth muscle activation by IL-4, IL-13, or allergen is sufficient, but not necessary, to induce AHR and show that 5 genes known to promote smooth muscle migration, proliferation and contractility are activated by IL-13 in smooth muscle in vivo. These observations demonstrate that IL-4Rα promotes AHR through multiple mechanisms and provide a model for testing smooth muscle-directed asthma therapeutics. For the microarray aspect of of the study, there were three groups of mice: 1. IL4R gene knockout (KO) mice 2. WT mice 3. IL4R KO mice that were also transgenic for a gene construct that expressed IL4R under the control of the smooth muscle-specific promoter from the SMP8 gene All mice were subjected to intratracheal IL13 exposure for 7 days, and whole lung RNA was prepared for microarray analysis 24 hours after the last instillation. Per treatment and genotype: Two RNA pools were made from four mice each. These were labeled and hybridized to make a total of 6 microarrays. RNA was labeled with the standard Affymetrix 3' labeling protocol to make cDNA that was hybridized to Mouse MOE 430 plus 2.0 GeneChips. Gene transcripts were identified that differed in their relative expression as a function of IL4R expression on the smooth muscle cells.
Project description:The IL-13 is a central mediator of allergic asthma. This project investigates the mechanisms by which IL-13 elicits the symptoms of asthma. Keywords: other
Project description:The IL-13 is a central mediator of allergic asthma. This project investigates the mechanisms by which IL-13 elicits the symptoms of asthma.
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.