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: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: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
Project description:Observational studies in human suggest involvement of vitamin A/retinoic acid (RA) signaling in the regulation of airway smooth muscle (ASM) function, but the precise mechanisms by which RA impacts ASM phenotype is not clear. Here, we generated trascriptional profiles from primary human ASM from 3 unrelated donoros cultured in control medium or medium containing BMS493 (an retinoic acid receptor antagonist)
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:CCAAT/Enhancer Binding Protein D (CEBPD) is a transcription factor that regulates genes involved in immune and inflammatory responses. Based on our previous observation that CEBPD expression increases in airway smooth muscle (ASM) with glucocorticoid exposure, we sought to better understand its role in the ASM transcriptomic response to glucocorticoids via knockdown experiments. Primary human airway smooth muscle (ASM) cells from four non-asthma donors were transfected with 25pmol of siRNA non-targeting control or siCEBPD SMARTpool using RNAiMax. Three days after transfection, cells were treated with 100nM Budesonide, 10ng/ml TNF-alpha, or both for 18 hours. RNA-Seq libraries were prepared with the Kapa mRNA HyperPrep Illumina Library kit. An Illumina HiSeq 2500 instrument was used to generate 125 base pair paired-end reads. STAR was used to align sequencing reads to the hg38 reference genome, and HTSeq was used to quantify transcript levels. DESeq2 was used to perform differential expression analysis.
Project description:Signalling pathways regulate all major cellular events in health and disease, including asthma development and progression. Complexity of human intracellular signalization can be explored using novel systemic approaches that exploit whole-transcriptome analysis. Cap-analysis-of-gene-expression (CAGE) is a method of choice for generating transcriptome libraries, as it interrogates only terminally capped mRNAs that have the highest probability to be translated into protein. In this study we for the first time systematically profiled differentially activated Intracellular Signalling Pathways (ISPs) in cultured primary human airway smooth muscle (ASM) cells from asthmatic (n=8) and non-asthmatic (n=6) subjects in a high-throughput assay, highlighting asthma-specific co-regulatory patterns. CAGE-libraries from primary human ASM cells were subject to massive parallel next generation sequencing, and a comprehensive analysis of ISP activation was performed using a recently developed technique OncoFinder. Analysis of 270 ISPs led to discovery of multiple pathways clearly distinguishing asthmatic from normal cells. In particular, we found 146 (p<0.05) and 103 (p<0.01) signalling pathways differentially active in asthmatic vs non-asthmatic samples. We identified seven clusters of coherently acting pathways functionally related to the disease. Pathways down-regulated in asthma mostly represented cell death-promoting pathways, whereas the up-regulated ones were mainly involved in cell growth and proliferation, inflammatory response and some specific reactions, including smooth muscle contraction and hypoxia - related signalization. Most of interactions uncovered in this study were not previously associated with asthma, suggesting that these results may be pivotal to development of novel therapeutic strategies that specifically address the ISP signature linked with asthma pathophysiology. Capped mRNA profiles of primary bronchial smooth muscle cells from 8 asthmatic and 6 healthy donors were generated by deep sequencing using Illumina HiSeq1500.
Project description:Rationale: Asthma and atopy shares common features including Th2-inflammation. However, impairment of airway function seems to be absent in atopy. Increased understanding of the complex cellular and molecular pathways defining the similarities and differences between asthma and atopy may be achieved by transcriptomic analysis (RNA-Seq). Hypothesis and Aims: As the airway smooth muscle (ASM) layer plays an important role in airway function, we hypothesized that the transcriptomic profile of the ASM layer in endobronchial biopsies is different between atopic asthma patients and atopic healthy controls. First, we examined the differences in transcriptomic profiles of the ASM layer in endobronchial biopsies between atopic mild, steroid-free asthma patients, and atopic and non-atopic healthy controls. Second, we investigated the association between the transcriptomic profiles of the ASM layer and airway function. Methods: This cross-sectional study included 12 steroid-free atopic asthma patients, 6 atopic, and 6 non-atopic healthy controls. RNA of ASM from 4 endobronchial biopsies per subject was isolated and sequenced (GS FLX+, 454/Roche). Ingenuity Pathway Analysis was used to identify gene networks. Comparison of the numbers of reads per gene in asthma and controls was based on the negative binomial distribution. At the current sample size the estimated false discovery rate was approximately 1%. Results: Yield of isolated RNA was 30-821ng. We identified 174 differentially expressed genes between asthma and atopic controls, 108 between asthma and non-atopic controls, and 135 between atopic and non-atopic controls. A set of 8 genes was identified, which seems to define asthma patients from non-asthmatic controls regardless of atopy. Four of these genes were significantly associated with airway hyperresponsiveness. Conclusion: A difference in transcriptomic profile of the airway smooth muscle layer in asthma patients compared to atopic and non-atopic healthy controls may lead to a different regulation of inflammatory pathways and of airway smooth muscle function and development resulting in impaired airway function. This cross-sectional transcriptomics study consisted of 2 visits. At visit 1, asthma patients (n=12), and healthy atopic (n=6) and non-atopic (n=6) controls were screened for eligibility to participate according to the in- and exclusion criteria. Spirometry and a methacholine bronchoprovocation test were performed. At visit 2, FEV1 reversibility was measured and 4 endobronchial biopsies per subject were collected during a bronchoscopy. Airway smooth muscle was collected from the biopsies by laser capture microdissection and total RNA isolated. cDNA was prepared using the Ovation RNA-Seq System (NuGEN). RNA-Seq was performed using the GS FLX+ instrument (454/Roche). Sequence reads were mapped against the human genome (hg19; UCSC). Comparison of the numbers of reads per gene between asthma and healthy controls was based on the negative binomial distribution and carried out with the R package DESeq including correction for multiple testing.