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:Mechanical overload in the heart induces pathological remodeling that typcially leads to heart failure. We sought to build an in vitro model of heart failure by applying cyclic stretch to engineered isotropic (iso) and anisotropic (aniso) NRVM tissues. We used micoarrays to determine the effects of longitudinal and transvserse cyclic stretch on gene expression in engineered NRVM cardiac tissues. We found that cyclic stretch induced up-regulation of several known indicators of heart faliure, independent of the direction of stretch.
Project description:The effect of cyclic mechanical stretch (0.5 Hz, 10-21% elongation) on gene expression of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) was studied using RNA sequencing.
Project description:In order to investigate the effects of downregulated autophagy in TM cells response to mechanical stretch, we conducted gene expression analysis in human TM cells deficient in autophagy and subjected to cyclic mechanical stretch. For this, three independent strains of primary human TM cells were transfected with a cocktail of siRNAs to specifically silence the expression of the autophagy genes Atg5 and Atg7 (siAtg5/7), and subjected to cyclic mechanical stress (15% elongation, 1 cycle/sec, 24h).
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: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).
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
Project description:Cyclic stretch of alveoli is characteristic of mechanical ventilation, and is postulated to be partly responsible for the lung injury and inflammation in ventilator induced lung injury. We propose that miRNAs may regulate some of the stretch response and, therefore, hypothesized that miRNAs would be differentially expressed between stretched and unstretched rat alveolar epithelial cells (RAECs).
Project description:Mechanical overload in the heart induces pathological remodeling that typcially leads to heart failure. We sought to build an in vitro model of heart failure by applying cyclic stretch to engineered isotropic (iso) and anisotropic (aniso) NRVM tissues. We used micoarrays to determine the effects of longitudinal and transvserse cyclic stretch on gene expression in engineered NRVM cardiac tissues. We found that cyclic stretch induced up-regulation of several known indicators of heart faliure, independent of the direction of stretch. NRVMs were seeded on silicone membranes coated with isotropic (iso) fibronectin (FN) or micropatterned with FN (aniso), cultured statically for 1h (t=0h), and stretched for increasing amount of time (t=6h, 24h, 96h) before RNA extraction and hybridization on Affymetrix microarrays. For aniso tissues, stretch was applied in either the longitudinal (long) or transverse (trans) direction. RNA was collected over six primary NRVM harvests and thus RNA was also extracted and analyzed from samples seeded for 1h (at t=0h) on iso FN to be used to normalize across cell harvests.