Epithelial basal cells (BCs) are an important stem cell population of the airways. We purified BCs from a KRT5-GFP transgenic mouse line and used Affymetrix arrays to compare there gene expression to that of non-BC epithelium.
Basal cells as stem cells of the mouse trachea and human airway epithelium.
Specimen part, Cell line
View SamplesAcute lung inflammation can alter the pulmonary function of susceptible individuals and exacerbate the pathogenesis of chronic inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma. Exposure to lipopolysaccharide (LPS) or endotoxin, a constituent of outer cell membrane of gram negative bacteria, induces airway inflammation that is primarily characterized by increased polymorphonuclear neutrophils (PMNs) at early time points. Because LPS is present in variety of occupational and home environments and is an active constituent of cigarette smoke it is a risk factor for increasing prevalence and severity of non-occupational COPD, for adult onset of asthma and for wheezing in children. In airway epithelial cells, LPS stimulation increases mucin gene expression and mucous production. Hypersecretion of mucus overwhelms the ciliary clearance and obstructs airways, causing morbidity and mortality in chronic inflammatory respiratory lung diseases. In addition, acute bacterial infection contributes to the exacerbation of chronic airway diseases, specifically in advanced COPD and CF subjects, leading to increased healthcare burden and higher mortality. Bcl-2, a prosurvival protein that inhibits cell death plays a key role in normal cellular homeostasis and regulates the integrity of the mitochondrial and endoplasmic reticulum membranes. Gain- and loss-of-function studies showed that Bcl-2 expression sustains hyperplastic epithelial cells, and Bcl-2 expression is elevated in airway epithelial cells of subjects with cystic fibrosis and asthma. The present study investigated which inflammatory mediators induce mucous cell metaplasia and Bcl-2 expression following LPS exposure. Microarray analyses of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and 2 post LPS exposure were analyzed.
Intracellular insulin-like growth factor-1 induces Bcl-2 expression in airway epithelial cells.
Sex
View SamplesInflammatory breast cancer (IBC) is the most aggressive form of breast cancer. Treatment options are limited and the mechanisms underlying its aggressiveness are poorly understood. Intermittent hypoxia (IH) causes oxidative stress and is emerging as important regulator of tumor metastasis. Vessels in IBC tumors were shown to be immature, which is a primary cause of IH. We therefore investigated the relevance of IH for the modulation of gene expression in IBC cells in order to assess IH as potential regulator of IBC aggressiveness. Gene array analysis of IBC cells following chronic IH (45-60 days) demonstrated increased expression of pro-metastatic genes of the extracellular matrix, such as tenascin-C (TNC; an essential factor of the metastatic niche) and matrix metalloproteinase 9 (MMP9), and of pro-inflammatory processes, such as cyclooxygenase-2 (COX-2). Investigating the oxidative stress-dependent regulation of TNC, we found a gradual sensitivity on mRNA and protein levels. Oxidative stress activated NF-E2-related factor 2 (Nrf2), c-Jun N-terminal kinase (JNK), c-Jun and nuclear factor B (NF-B), but TNC upregulation was only dependent on NF-B activation. Pharmacological inhibition of inhibitor of NF-B (IB) phosphorylation as well as overexpression of IB prevented TNC, MMP9 and COX-2 induction, whereas the pro-inflammatory cytokine interleukin-1 (IL-1) increased their expression levels. Analysis of the gene array data showed NF-B binding sites for 64% of all upregulated genes, linking NF-B and IH-dependent regulation of pro-metastatic gene expression in IBC cells. Our results provide a first link between intermittent hypoxia and pro-metastatic gene expression in IBC cells, revealing a putative novel mechanism for the high metastatic potential of IBC.
Intermittent hypoxia confers pro-metastatic gene expression selectively through NF-κB in inflammatory breast cancer cells.
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Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium.[corrected].
Specimen part, Treatment
View SamplesThe airways of the human lung are lined by an epithelium made up of ciliated and secretory luminal cells and undifferentiated p63+ Krt5+ basal cells. The integrity of this epithelium and its ability to act as a selective barrier are critical for normal lung function. In other epithelia there is evidence that transcription factors of the evolutionarily conserved grainyheadlike (GRHL) family play key roles in co-ordinating the expression of numerous proteins required for epithelial morphogenesis, differentiation, remodeling and repair. However, little is known about their function in the adult lung. Here, we focus on the role of GRHL2 in primary human bronchial epithelial (HBE) cells, using either shRNA or a dominant negative protein (DN-GRHL2) to inhibit its function. We follow changes in epithelial phenotype, and in gene transcription using RNA-seq or microarray analysis, both in undifferentiated basal cells and in cells differentiating in air-liquid interface culture into a mucociliary epithelium with transepithelial electrical resistance. We identify several hundreds of genes that are directly or indirectly regulated by GRHL2. Using ChIP-seq to map sites of GRHL2 binding in the basal cells we identify 7,687 potential primary targets, and confirm that GRHL2 binding is strongly enriched near GRHL-regulated genes. Different subsets of the large cohort of potential GRHL2 targets appear to be active in basal and differentiated cells. Taken together, the results strongly support the hypothesis that GRHL2 plays a key role in regulating many physiological functions of human airway epithelium, including those involving cell adhesion, polarity and morphogenesis. Overall design: Frozen primary human bronchial epithelial (HBE) cells were obtained from three donors. Passage 2 cells at 40% confluence were infected with H2B-GFP or DN-GRHL2 lentivirus and 1 mg/ml puromycin added 48 h later. At confluence, Doxycycline 0.5 mg/ml was added for 24 h. RNA-seq was performed on all six samples, as well as samples from two donors that were not infected.
Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium.[corrected].
Subject
View SamplesThe airways of the human lung are lined by an epithelium made up of ciliated and secretory luminal cells and undifferentiated p63+ Krt5+ progenitors. The integrity of this epithelium and its ability to act as a selective barrier are critical for normal lung function. In other epithelia there is evidence that transcription factors of the evolutionarily conserved grainyheadlike (GRHL) family play key roles in co-ordinating the expression of numerous proteins required for epithelial morphogenesis, differentiation, remodeling and repair. However, little is known about their function in the adult lung.
Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium.[corrected].
Specimen part, Treatment
View SamplesThe airways of the human lung are lined by an epithelium made up of ciliated and secretory luminal cells and undifferentiated p63+ Krt5+ basal cells. The integrity of this epithelium and its ability to act as a selective barrier are critical for normal lung function. In other epithelia there is evidence that transcription factors of the evolutionarily conserved grainyheadlike (GRHL) family play key roles in co-ordinating the expression of numerous proteins required for epithelial morphogenesis, differentiation, remodeling and repair. However, little is known about their function in the adult lung.
Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium.[corrected].
Specimen part, Treatment
View SamplesChromodomains are found in many regulators of chromatin structure. Most of them recognize methylated histones. Here, we investigate the role of the Corto chromodomain. This Drosophila melanogaster Enhancer of Polycomb and Trithorax is involved in both silencing and activation of gene expression. Overexpression of Corto chromodomain (CortoCD) in transgenic flies show that this domain is critical for Corto function and behaves as a chromatin-targeting module. Mass spectrometry analysis of peptides pulled down by CortoCD from nuclear extracts reveals that they correspond to nuclear ribosomal proteins (RPs). Notably, CortoCD binds with high affinity RPL12 tri-methylated on lysine 3 (RPL12K3me3) as demonstrated by real-time interaction analyses. Co-localization of Corto and RPL12 with active epigenetic marks on polytene chromosomes suggests that they are involved in fine-tuning transcription of genes located in open chromatin. Hence, pseudo-ribosomal complexes composed of various RPs might participate in regulation of gene expression in connection with chromatin regulators. RNA-seq analysis of wing imaginal discs overexpressing either Corto or RPL12 show that most deregulated genes are shared by both factors. Interestingly, these common targets are enriched in RP genes suggesting that Corto and RPL12 are involved in dynamic coordination of ribosome biogenesis. Overall design: To address the role of Corto and RPL12 in regulation of transcription, we deep-sequenced transcripts of wing imaginal discs from third instar larvae over-expressing either FH-cortoCD or RpL12-Myc under control of the wing-specific scalloped::Gal4 driver (sd::Gal4>UAS::FH-cortoCD or sd::Gal4>UAS::RpL12-Myc). Total RNA from FH-cortoCD or RpL12-Myc, the sd::Gal4/+ control or a w1118 reference line were isolated from pools of wing imaginal discs and subjected to RNA-seq on an Illumina high throughput sequencer.
New partners in regulation of gene expression: the enhancer of Trithorax and Polycomb Corto interacts with methylated ribosomal protein l12 via its chromodomain.
Specimen part, Subject
View SamplesThe endothelial transcription factor Erg (Ets Related Gene) plays an important role in homeostasis and angiogenesis by regulating many endothelial functions including survival and junction stability. Here we show that Erg regulates endothelial cell migration. Transcriptome profiling of Erg-deficient endothelial cells (EC) identified 80 genes involved in cell migration as candidate Erg targets, including regulators of the Rho GTPases. Inhibition of Erg expression in human umbilical vein endothelial cells (HUVEC) resulted in decreased migration in vitro, whilst Erg over-expression using adenovirus caused increased migration. Live-cell imaging of Erg-deficient HUVEC showed a reduction in lamellipodia, in line with decreased motility. Both actin and tubulin cytoskeletons were disrupted in Erg-deficient EC, with a dramatic increase in tubulin acetylation. Amongst the most significant microarray hit was the cytosolic histone deacetylase (HDAC)-6, a regulator of cell migration. Rescue experiments confirmed that HDAC6 mediates the Erg-dependent regulation of tubulin acetylation and actin localization.
The transcription factor Erg regulates expression of histone deacetylase 6 and multiple pathways involved in endothelial cell migration and angiogenesis.
Specimen part
View SamplesBleaching gravid C. elegans followed by a short period of starvation of the L1 larvae is a routine method performed by worm researchers for generating synchronous populations for experiments. During the process of investigating dietary effects on gene regulation in L1 stage worms by single-worm RNA-Seq, we found that the density of resuspended L1 larvae affects expression of many mRNAs. Specifically, a number of genes related to metabolism and signalling are highly expressed in worms arrested at low density, but are repressed at higher arrest densities. We generated a GFP reporter strain based on one of the most density-dependent genes in our dataset – lips-15 – and confirmed that this reporter was expressed specifically in worms arrested at relatively low density. Finally, we show that conditioned media from high density L1 cultures was able to downregulate lips-15 even in L1 animals arrested at low density, and experiments using daf-22 mutant animals demonstrated that this effect is not mediated by the ascaroside family of signalling pheromones. Together, our data implicate a soluble signalling molecule in density sensing by L1 stage C. elegans, and provide guidance for design of experiments focused on early developmental gene regulation. Overall design: L1 Larvae arrested in M9 media at different densities were isolated for single L1 RNA-sequencing
Effects of Larval Density on Gene Regulation in <i>Caenorhabditis elegans</i> During Routine L1 Synchronization.
Cell line, Subject
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