Project description:Background: Increased proliferation of airway smooth muscle (ASM) cells leading to hyperplasia and increased ASM mass is one of the most characteristic features of airway remodelling in asthma. A bioactive lipid, sphingosine-1-phosphate (S1P), has been suggested to affect airway remodelling by stimulation of human ASM cell proliferation. Objective: To investigate the effect of S1P on signalling and regulation of gene expression in ASM cells from healthy and asthmatic individuals. Methods: ASM cells grown from bronchial biopsies of healthy and asthmatic individuals were exposed to S1P. Gene expression was analysed using microarray, real-time PCR and western blotting. Receptor signalling and function was determined by mRNA knockdown and intracellular calcium mobilisation experiments. Results: S1P potently regulated the expression of more than 80 genes in human ASM cells, including several genes known to be involved in the regulation of cell proliferation and airway remodelling (HBEGF, TGFB3, TXNIP, PLAUR, SERPINE1, RGS4). S1P acting through S1P2 and S1P3 receptors activated intracellular calcium mobilisation and extracellular signal-regulated and Rho-associated kinases to regulate gene expression. S1P-induced responses were not inhibited by corticosteroids and did not differ significantly between ASM cells from healthy and asthmatic individuals. Conclusion: S1P induces a steroid-resistant, pro-remodelling pathway in ASM cells. Targeting S1P or its receptors could be a novel treatment strategy for inhibiting airway remodelling in asthma. Airway smooth muscle cells from 3 healthy donors were cultured and stimulated for 4 h with sphingosine-1-phosphate (100 nM) or medium control. Total RNA was extracted and analysed using Affymetrix Human Exon 1.0 ST arrays.
Project description:Background: Increased proliferation of airway smooth muscle (ASM) cells leading to hyperplasia and increased ASM mass is one of the most characteristic features of airway remodelling in asthma. A bioactive lipid, sphingosine-1-phosphate (S1P), has been suggested to affect airway remodelling by stimulation of human ASM cell proliferation. Objective: To investigate the effect of S1P on signalling and regulation of gene expression in ASM cells from healthy and asthmatic individuals. Methods: ASM cells grown from bronchial biopsies of healthy and asthmatic individuals were exposed to S1P. Gene expression was analysed using microarray, real-time PCR and western blotting. Receptor signalling and function was determined by mRNA knockdown and intracellular calcium mobilisation experiments. Results: S1P potently regulated the expression of more than 80 genes in human ASM cells, including several genes known to be involved in the regulation of cell proliferation and airway remodelling (HBEGF, TGFB3, TXNIP, PLAUR, SERPINE1, RGS4). S1P acting through S1P2 and S1P3 receptors activated intracellular calcium mobilisation and extracellular signal-regulated and Rho-associated kinases to regulate gene expression. S1P-induced responses were not inhibited by corticosteroids and did not differ significantly between ASM cells from healthy and asthmatic individuals. Conclusion: S1P induces a steroid-resistant, pro-remodelling pathway in ASM cells. Targeting S1P or its receptors could be a novel treatment strategy for inhibiting airway remodelling in asthma.
Project description:Persistent severe asthma is associated with hyper-contractile airways and structural changes in the airway wall, including an increased airway smooth muscle (ASM) mass. This study used gene expression profiles from asthmatic and healthy airway smooth muscle cells grown in culture to identify novel receptors and pathways that potentially contributed to asthma pathogenesis. We used microarrays to compare the gene expression between asthmatic and healthy airway smooth muscle cells to understand the underlying pathway contributing the differences in cellular phenotypes Asthmatic airway smooth muscle cells (ASMC) are intrinsically different and have a differential transcriptional response to pro-fibrotic, pro-proliferation and pro-inflammatory stimuli than ASMC from healthy patients. We sought to identify genes that are differentially expressed between asthmatic and healthy ASMC under various stimulations which mimic the asthmatic airways. To this end, we obtained human ASMC from bronchial biopsies and explanted lungs from doctor diagnosed asthmatic patients (n=3) and healthy controls (n=3). The ASMC were then grown in culture and treated with pro-fibrotic (Transforming growth factor beta (TGFβ)), pro-proliferation (Fetal Bovine Serum (FBS)) and pro-inflammatory stimuli (Interleukin-1 beta (IL-1β)) for 8 hours. Gene expression was then evaluated using Affymetrix Human Gene 1.0ST arrays.
Project description:Aberrant proliferation of pulmonary arterial smooth muscle (PASMCs) cells are a defining characteristic of pulmonary arterial hypertension (PAH) and leads to increased vascular resistance, elevated pulmonary pressure, and right heart failure. The Sphingosine kinase 1 (SPHK1)/Sphingosine-1 phosphate/ Sphingosine-1 phosphate receptor 2 pathway promotes vascular remodeling and induces PAH. The aim of this study was to identify genes and cellular processes that are modulated by over-expression of SPHK1 in human PASMCs (hPASMCs). RNA was purified and submitted for RNA sequencing to identify differentially expressed genes. Using a corrected p-value threshold of <0.05, there were 294 genes significantly up-regulated while 179 were significantly down-regulated. Predicted effects of these differentially expressed genes was evaluated using the freeware tool Enrichr to assess general gene set over-representation (enrichment) and Ingenuity Pathway Analysis (IPA™) for upstream regulator predictions. We found a strong change in genes that regulated the cellular immune response. IL6, STAT1, and PARP9, were elevated in response to SPHK1 over-expression in hPASMCs. The gene set enrichment mapped to a few immune modulatory signaling networks, including IFNG. Furthermore, STAT1 protein was elevated in primary hPASMCs isolated from PAH patients. In conclusion, these data suggest a role of Sphk1 regulates pulmonary vascular immune response in PAH.
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: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:Smooth muscle differentiation has been proposed to sculpt airway epithelial branches in mammalian lungs. Serum response factor (SRF) acts with its cofactor myocardin to promote the expression of contractile smooth muscle markers. However, smooth muscle cells exhibit a variety of phenotypes beyond contractile that are independent of SRF-myocardin-induced transcription. To determine whether airway smooth muscle exhibits phenotypic plasticity during embryonic development, we deleted Srf from the pulmonary mesenchyme. Srf-mutant lungs branch normally, and the mesenchyme exhibits normal cytoskeletal features and patterning. scRNA-seq revealed an Srf-null smooth muscle cluster wrapping the airways of mutant lungs that lacks contractile smooth muscle markers but retains many features of control smooth muscle. Srf-null airway smooth muscle exhibits a synthetic phenotype, compared to the contractile phenotype of wildtype airway smooth muscle. Our findings reveal plasticity in mesenchymal differentiation during lung development and demonstrate that a synthetic smooth muscle layer is sufficient for airway branching morphogenesis.
Project description:Human airway smooth muscle cells were co-cultured with BEAS-2B epithelial cells (or Control). Airway smooth muscle RNA was extracted and sent for Illumina HT-12 micro-array to examine gene expression.
Project description:Persistent severe asthma is associated with hyper-contractile airways and structural changes in the airway wall, including an increased airway smooth muscle (ASM) mass. This study used gene expression profiles from asthmatic and healthy airway smooth muscle cells grown in culture to identify novel receptors and pathways that potentially contributed to asthma pathogenesis. We used microarrays to compare the gene expression between asthmatic and healthy airway smooth muscle cells to understand the underlying pathway contributing the differences in cellular phenotypes