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:Regulators of G protein signaling (RGS proteins) constrain G protein-coupled receptor (GPCR)-mediated and other responses throughout the body primarily, but not exclusively, through their GTPase activating (GAP) activity. Asthma is a highly prevalent condition characterized by airway hyper-responsiveness (AHR) to environmental stimuli resulting in part from amplified GPCR-mediated airway smooth muscle (ASM) contractility. Rgs2 or Rgs5 gene deletion in mice enhances AHR and ASM contraction whereas RGS4 knockout (KO) mice unexpectedly have decreased AHR due to increased production of the bronchodilator prostaglandin E2 (PGE2) by lung epithelial cells. Here we found that knockin mice harboring Rgs4 alleles encoding a point mutation (N128A) that sharply curtails RGS4 GAP activity had increased AHR, reduced airway PGE2 levels, and augmented GPCR-induced bronchial contraction compared to either RGS4 KO mice or WT controls. RGS4 interacted with the p85a subunit of PI3 kinase (PI3K) and inhibited PI3K-dependent PGE2 secretion elicited by TGFb in airway epithelial cells. Together these findings suggest that RGS4 affects asthma severity in part by regulating the airway inflammatory milieu in a G protein-independent manner.