Transcription profiling of human vascular smooth muscle cells in response to cyclical mechanical strain over a time series of 2, 4 and 24 hours to examine temporal patterns of gene expression in response to strain
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ABSTRACT: Compared the gene expression profiles of human vascular smooth muscle cells in response to cyclical mechanical strain over a time course of 2, 4 and 24 hours to examine temporal pattern of gene expression in response to strain.
Project description:Background: Basal cells within the human airway epithelium constitute the stem/progenitor cells for other epithelial cell types. Basal cells respond to mucosal injury and damage to the airway mucosa in an ordered sequence of spreading, migration, proliferation and phenotype shifting (differentiation) to other needed cell types. However, dynamic gene transcription in the early events of injury and repair has not been examined in these cells. Methodology and findings: Airway epithelial cells were obtained from donated lungs and grown in submersion culture on pliable membranes to obtain a pure population of basal cells. Microarrays were used to assess the transcriptome of basal cells 8 and 24 hr after mechanical injury (MI), or to cyclic stretch (CS) in a Flexcell system (0.5 Hz, 20% distension), or both treatments. We identified 121 signature genes with > 2-fold higher differential expression (DE) 8 hr after MI; expression of nearly all of these genes returned to baseline at 24 hr after injury. In cells subjected to CS, little change in DE was noted at 8 hr, whereas at 24 hr a CS signature of 1430 DE genes were identified. The MI signature was characterized by genes encoding growth factor receptors related to the EGF pathway, IL-6, IL-8 and IL-33, extracellular matrix components, and NF-kB and p38-MAPK signaling pathways, whereas the CS signature was characterized by a broad range of genes that did not identify specific signaling pathways. Combined MI and CS at 8 hr elicited DE of down-regulated genes not seen with either stimulus alone, and at 24 hr elicited DE that was similar to that seen with CS alone. Conclusion and significance: The human airway basal epithelial cell transcription signature in the first hours after MI, after CS, and after both stimuli identifies unique differentially expressed genes and pathways that may be important in the early molecular response and biology to airway injury. Total RNA obtained from primary (AEC) and differentiated (dAEC) human airway epithelial cells subjected to 8 or 24 hours in vitro mechanical or cyclic stretch or both injuries compared to sham control as well as to type of injury. Cells were collected from four donated lungs and cultured separated in submission or air liquid interface condition prior to injury for various durations.
Project description:With gene expression profiling it was aimed to identify the differentially expressed genes associated with the regulation of the cytoskeleton to investigate the stretch-induced cell alignment mechanism. A whole genome microarray based analysis of the stretch-induced gene expression changes was done. Gene expression was measured at the beginning of the alignment process showing first reoriented cells after 5 h stretching and at the end after 24 h, where nearly all cells are aligned. Cyclic mechanical stretching of cells results in cellular alignment perpendicular to the stretch direction regulating cellular response. This stress response is assumed to be an adaptation mechanism to reduce extensive stretching but also acts as architectural restructuring changing performance and biomechanics of the tissue. Gene expression profiling of control vs. stretched primary human dermal fibroblasts after 5 h and 24 h demonstrated the regulation of differentially expressed genes associated with metabolism, differentiation and morphology. Primary human dermal fibroblasts from ten donors were cultured on Bioflex culture plates and stretched for 5h and 24 h or left untreated to avoid changes according to cell culturing. Each of the subject provided 4 samples (control/treated and 5hrs/24hrs) resulting in 40 samples total.
Project description:Ventilator induced lung injury can lead to serious conditions like ARDS which are associated with a high mortality (around 30%, Stapleton et al., Chest, 2005). We hypothesized that changes of expression levels of different genes would lead us to the identification of critical target genes, which might influence the inflammation and outcome associated with this condition. We used human whole genome U133 Plus 2.0 microarrays to detail the changes of gene expression and identified distinct classes of up-regulated genes during this process. Confluent non strained and strained human Calu-3 cells were selected for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Acute respiratory distress syndrome (ARDS) is a catastrophic form of acute lung injury (ALI). The necessity for mechanical ventilation (MV) renders patients at risk for ventilator induced lung injury (VILI). Exposure to repetitive cyclic stretch (CS) and/or over-inflation exacerbates injury. Reducing tidal volume (VT) is the only therapeutic strategy shown to mitigate morbidity and mortality. Cyclic stretch has been shown to differentially regulate gene expression in part through the activation of mammalian mitogen-activated protein kinase (MAPK). Although these studies have shown both molecular and cellular alterations, no unifying hypothesis to explain MV-induced lung injury has emerged. In the current study, we hypothesized that coordinated expression of cyclic stretch (CS)-responsive genes relies on the presence of common CS-sensitive regulatory elements. To identify CS-responsive genes, we undertook a comparative examination of the gene expression profile of human bronchial epithelial airway (Beas-2B) cells in response to various injurious stimuli involved in the pathogenesis of acute lung injury (ALI)/Ventilator induced lung injury (VILI): cyclic stretch, tumor necrosis factor alpha (TNF-a), and lipopolysaccharide (LPS). Experiment Overall Design: Human Bronchial Epithelial Cells (Beas-B2) cells grown on silicon elastic plates coated with Type I collagen (Flexercell International, McKeesport, PA) were exposed to six regiments for 4 h: 1) control (static, [control]); 2) mechanical stretch (25 PKa, 30 cycles per min, [stretch]); 3) LPS (1 mcg/ml [LPS]); 4) TNF-α (20 ng/ml; [TNF]); 5) mechanical stretch plus LPS [LPS+S], and 6) mechanical stretch plus TNF-α [TNF+S]. Total RNA (duplicate experiments) was extracted using TRIZOL reagent (as per manufactures specifications) and purified using Qiagen mRNA purification Kit (as per manufacturers specifications). mRNA was hybridized to Affymetrix Human U133plus2.0 chips. Probe based analysis, background reduction, and quantile data normalization was performed in MeV 4.0 of TM4 using Robust Multi-array Average (RMA).
Project description:Several different mechanical signals have been proposed to control the extent and pattern of myocardial growth and remodeling, though this has largely been studied using in vitro model systems that are not representative of intact myocardium or in vivo models in which isolating the effects of individual candidate stimuli is exceedigly difficult. We used a unique tissue culture system that allows the simultaneous control of multiple mechanical inputs and other potentially confounding stimuli (e.g., hormonal). Following a 12 hour culture period under prescribed mechanics, we used microarrays to identify genes that are up- or down-regulated in response to different amounts of mean stretch and cyclic shortening. Muscles were dissected (one from each of 12 different male LBN-F1 rats) and cultured for 12 hours in a pseudo-sterile muscle culture system under one of four mechanical input schemes (i.e., three biological replicates per mechanical input group). We prescribed low or high values of both time averaged stretch and cyclic shortening. Specifically, we targeted 4% or 16% mean stretch (from slack length) and 4% of 16% cylic shortening (% of slack length) over the 12 hour culture period to give the following four groups: high mean stretch x high shortening (group A); high mean stretch x low shortening (group B); low mean stretch x low shortening (group C); low mean stretch x high shortening (group D). This 2 x 2 factorial design allowed us to identify individual genes and/or molecular pathways that might be regulated by one or both of these mechanical inputs indpendent from other candidate mechanical or hormonal stimuli.
Project description:AVICs were exposed to cyclic stretch to examine the role of mechanical stimuli on gene expression AVICs cultured on collagen 1 coated Bioflex were exposed to 14% stretch at 1 hz or static conditions using a Flexcell-5000 14% stretch was the experimental condition while the static condition was the control
Project description:To identify the consequences of mechanical stress of differentiated cardiac muscles from healthy- and PPCM individuals. RNA-sequencing data was obtained from 4 individuals from 2 families. Each family had one member with PPCM and one healthy. Individual 1 and 2 were sisters, one healthy, one with PPCM. Individual 3 and 4 were a healthy mother and PPCM daughter. From each patient 4, 6, 1 and 3 clones were derived, respectively. From each clone multiple pairs of cells were collected and either stretched or left static to a total of 40 pairs, with 2 unpaired static samples.
Project description:Engineered cardiac tissues (ECTs) are platforms to investigate cardiomyocyte maturation and functional integration, to evaluate the feasibility of generating implantable tissues for cardiac repair and regeneration, and may be useful models for pharmacology and toxicology bioassays. These ECTs rapidly mature in vitro to acquire the features of functional cardiac muscle and respond to mechanical load with increased proliferation and maturation. ECTs can be generated from various immature cardiac cell sources and little is known regarding the broad changes in regulatory transcript expression that occur in these in vitro tissues during normal maturation and in response to mechanical or pharmacologic interventions. We tested the hypothesis that global ECT gene expression patterns are sensitive to mechanical loading conditions and tyrosine kinase inhibitors, similar to the maturing myocardium. We generated 3D ECTs from day 14.5 rat embryo ventricular cells, as previously published, and then treated constructs after 5 days in culture for 48 hours with mechanical stretch (5%, 0.5 Hz) and/or the p38MAPK (p38 mitogen-activated protein kinase) selective inhibitor BIRB796. RNA was isolated from 3 sets of experiments and assayed using a standard Agilent rat 4x44k V3 microarray and Pathway Analysis software for transcript expression fold changes and changes in regulatory molecules and networks. At the threshold of a 1.5 fold change in expression, mechanical stretch altered 1,559 transcripts, versus 1,411 for BIRB796, and 1,846 for stretch plus BIRB796. As anticipated, top pathways altered in response to these stimuli include Cellular Development, Cellular Growth and Proliferation; Tissue Development; Cell Death, Cell Signaling, and Small Molecule Biochemistry as well as numerous other pathways. Changes in transcript expression were confirmed by quantitative-PCR for selected regulatory molecules. Thus, ECTs display a broad spectrum of altered gene expression in response to mechanical load and/or tyrosine kinase inhibition, reflecting the complex regulation of proliferation, differentiation, and architectural alignment that occurs during ECT maturation and adaptation. This approach can now be used to test the role of individual molecules and pathways on the regulation of ECT maturation and remodeling. 7 and 4 biological replicates with four groups (control, mechanical stretch, BIRB and mechanical stretch with BIRB)
Project description:Mechanical stress is a potent regulator of cell growth, contractility and gene regulation. Abnormal uterine distension during pregnancy increases the risk of preterm birth and likely activates crosstalk between multiple signaling networks with protein phosphorylation playing a critical role. Telomerized human uterine smooth muscle cells were exposed to 18% biaxial stretch for 5 min and the phosphoproteome was probed by mass spectrometry. We observed specific phospho-activation of mitogen activated protein kinase at threonine 183 and tyrosine 185, myosin regulatory light chain 9 at threonine 19, and heat shock protein 27 at serine 82. Our analysis revealed protein phosphorylation changes in signaling pathways related to actin cytoskeleton remodeling, activation of the focal adhesion kinase pathway, smooth muscle contraction and mechanistic target of rapamycin activation. These data point to potential mechanistic links between stretch-induced phosphorylation and development of the contractile phenotype in myometrial cells.
Project description:Prescribed exercise has the potential to ameliorate tissue repair or regeneration and therefore is gaining increasing importance in regenerative rehabilitation. Osteocytes are an appealing type of bone cell to target by regenerative rehabilitation protocols due to their mechanosensitive and secretory nature. Making use of tandem liquid chromatography-mass spectrometry (LC-MSMS) as well as curated bioinformatics, we examined the secretome of mouse and human osteocytic bone cells cultured under cyclic tension delivered by a computer-controlled bioreactor. Quantitative SWATH MS analysis of the secretome secreted by mechanically stimulated cells revealed differential expression of 13 out of 759 secreted factors in mouse and 16 out of 276 in human osteocytic cells. GO enrichment analysis suggested that response to oxidative stress was the most predominant biological process in mouse and cholesterol or lipoprotein-related in human cells. Ossification and bone remodelling and manganese transport were 2 overrepresented process networks common to both mouse and human osteocytic cells