Project description:Interleukin (IL)-17 plays an important and protective role in host defence and has been demonstrated to orchestrate airway inflammation by cooperating with and inducing proinflammatory cytokines. Mircoarrays were used to identify immediate-early/ primary response IL-17A-dependent gene transcripts in primary human bronchial ASM cells from mild asthmatic and healthy individuals. To evaluate IL-17A-inducible gene transcripts, primary human bronchial ASM cells from 3 mild asthmatic and 3 healthy donors were treated for 2h with IL-17 [10ng/ml] and were probed with the Affymetrix GeneChip array. The 2h time point was carefully chosen in order to identify primary response gene targets and to avoid confounding autocrine mechanisms mediating indirect, or late-phase gene expression responses. Non-stimulated ASM cells from the same patients were used as controls.
Project description:We previously demonstrated that the transcription factor, KLF15, is a glucocorticoid-regulated gene that represses primary human airway smooth muscle (ASM) proliferation. Here, we show that KLF15 also represses ASM hypertrophy. To uncover the mechanistic basis for these effects, we integrated transcriptome data from KLF15 over-expression with genome-wide analysis of RNA Polymerase II (RNAPII) and glucocorticoid receptor (GR) occupancy (i.e. ChIP-seq). This led us to identify PLCD1 as both a KLF15-regulated gene and a repressor of ASM hypertrophy.
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:Glucocorticoids (GCs) and protein kinase A (PKA)-activating agents (beta-adrenergic receptor agonists) are mainstream asthma therapies based on their ability to prevent or reverse excessive airway smooth muscle (ASM) constriction. Their abilities to regulate another important feature of asthma - excessive ASM growth are poorly understood. Recent studies have suggested that GCs render agents of inflammation such as interleukin 1beta and tumor necrosis factor alpha mitogenic to ASM, via suppression of (antimitogenic) induced cyclooxygenase-2-dependent PKA activity. To further explore the mechanistic basis of these observations, we assessed the effects of epidermal growth factor and interleukin 1beta stimulation, and the modulatory effects of GC treatment and PKA inhibition, on the ASM transcriptome by microarray analysis. Experiment Overall Design: Human ASM cultures were generated from trachea of 4 unidentified donors and used in passage 5-8. These cells were used to generate cells stabely expressing a PKA inhibitor (PKI) or GFP (control), which were then grown to confluence, serum starved for 24h, and stimulated with IL-1b, EGF,or both (E+I) in presence or absence of Fluticasone (Flu, 30 min pretreatment). After 8h stimulation cells were washed and total RNA isolated using TRIzol as per manufacturer's protocol. Gene expression was analyzed in 4 different cultures derived from 4 different donors (for a total of 3-4 microarrays per condition).
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:Haplotype-dependent allele-specific methylation (hap-ASM) can impact disease susceptibility, but maps of this phenomenon using stringent criteria in disease-relevant tissues remain sparse. Here we apply array-based and Methyl-seq approaches to multiple human tissues and cell types, including brain, purified neurons and glia, T lymphocytes, and placenta, and identify 795 hap-ASM differentially methylated regions (DMRs) and 3,082 strong methylation quantitative trait loci (mQTLs), most not previously reported. More than half of these DMRs have cell type-restricted ASM, and among them are 188 hap-ASM DMRs and 933 mQTLs located near GWAS signals for immune and neurological disorders. Targeted bis-seq confirmed hap-ASM in 12/13 loci tested, including CCDC155, CD69, FRMD1, IRF1, KBTBD11, and S100A*-ILF2, associated with immune phenotypes, MYT1L, PTPRN2,CMTM8 and CELF2, associated with neurological disorders, NGFR and HLA-DRB6, associated with both immunological and brain disorders, and ZFP57, a trans-acting regulator of genomic imprinting. Polymorphic CTCF and transcription factor (TF) binding sites are over-represented among hap-ASM DMRs and mQTLs, and analysis of the human data, supplemented by cross-species comparisons to Macaca mulattamacaques, indicates that CTCF and TF binding likelihood predicts the strength and direction of the allelic methylation asymmetry. These results show that hap-ASM is highly tissue-specific; an important trans-acting regulator of genomic imprinting is regulated by this phenomenon; variation in CTCF and TF binding sites is an underlying mechanism in primary tissues, and maps of hap-ASM and mQTLs reveal regulatory sequences underlying supera- and sub-threshold GWAS peaks in immunological and neurological disorders.