Transcription profiling of human dermal fibroblasts after 3 hours of cyclic mechanical loading compared with ni loading - collagen 1 hydrogel dynamic loading tests
Ontology highlight
ABSTRACT: Cell viability and global gene expression was anayzed from collagen 1 hydrogel scaffolds following 3 hours of cyclic mechanical loading and compared with non-loaded scaffolds. Experiment Overall Design: 6 samples are analyzed (2 sets in triplicate). The first set is the Loaded condition in which Collagen 1 hydrogels seeded with Human dermal fibroblasts underwent cyclic loading of 0.1Hz for 180 minutes at 37 degrees Celsius. The second set is the control Unloaded condition in which the Collagen 1 hydrogels seeded with Human dermal fibroblasts are incubated at 37 degrees Celsius with no loading.
Project description:Cell viability and global gene expression was anayzed from collagen 1 hydrogel scaffolds following 3 hours of cyclic mechanical loading and compared with non-loaded scaffolds. Keywords: human dermal fibroblasts; dynamic cell culture; mechanical stress
Project description:Background and Aims: Bowel smooth muscle experience mechanical stress constantly during normal function, and unusual mechanical stressors in various disease settings. Here, we test the hypothesis that pathologic mechanical stress could alter transcription to induce smooth muscle phenotypic class switching. Methods: Primary human intestinal smooth muscle cells (HISMCs), seeded on electrospun aligned poly-ε-caprolactone nano-fibrous scaffolds, were subjected to uniaxial 3% cyclic stretch at 1 Hz (loaded) or kept unloaded in culture for 6 hours. Bulk total RNA sequencing, RT-qPCR, and quantitative immunohistochemistry defined loading-induced changes in gene expression. NicheNet predicted how differentially expressed genes might impact HISMCs and other bowel cells. Results: Loading induced differential expression of 2500 genes in HISMCs. Loaded HISMCs had a less contractile phenotype, with increased expression of synthetic SMC genes, proinflammatory cytokines, and altered expression of axon guidance molecules, growth factors and morphogens. Many differentially expressed genes encode secreted ligands that could act cell-autonomously on smooth muscle, but also on other cells in the bowel wall. Discussion: HISMCs demonstrate remarkably rapid phenotypic plasticity in response to mechanical stress that may convert contractile HISMC into proliferative fibroblast-like cells or proinflammatory cells. These mechanical stress-induced changes in HISMC gene expression may be relevant for human bowel disease.
Project description:Long-term dynamic compression enhanced the mechanical properties of MSC-seeded constructs only when loading was initiated after 21 days of chondrogenic differentiation. This study examined the molecular differences of chondrogenic MSCs compared to undifferentiated MSCs (TGF-beta vs no TGF-beta) and the effects of dynamic loading on MSC chondrogenesis (loading vs free-swelling).
Project description:Long-term dynamic compression enhanced the mechanical properties of MSC-seeded constructs only when loading was initiated after 21 days of chondrogenic differentiation. This study examined the molecular differences of chondrogenic MSCs compared to undifferentiated MSCs (TGF-beta vs no TGF-beta) and the effects of dynamic loading on MSC chondrogenesis (loading vs free-swelling). Free-swelling MSC-seeded constructs were cultured for 21 days in chemically defined media. Chondrogenesis was induced with TGF-beta3. Undifferentiated controls were maintained in parallel. After 21 days of chondrogenic differentiation, a subset of constructs were subjected to 21 days of dynamic compressive loading. On days 21 and 42, construct mechanical properties and biochemical content were assessed. Microarray analysis was carried out on day 3, day 21 and day 42 constructs. 6 arrays.
Project description:To explore whether the application of FGF with different isoelectric points in wounds with different pH values, GelMA hydrogels with different pH values were prepared to maintain the wounds microenvironment with the same pH values, in which aFGF and bFGF were loaded as well.interferes with the healing process to different degrees,
Project description:The advent of high-throughput measurements of gene expression and bioinformatics analysis methods offers new ways to study gene expression patterns. The primary goal of this study was to determine the time sequence for gene expression in a bone subjected to mechanical loading, during key periods of the bone formation process, including expression of matrix-related genes, the appearance of active osteoblasts, and bone desensitization. A standard model for bone loading was employed in which the right forelimb was loaded axially for three minutes per day, while the left forearm served as a non-loaded, contralateral control. We evaluated loading-induced gene expression over a time course of 4 hours to 32 days after the first loading session. Six distinct, time-dependent patterns of gene expression were identified over the time course and categorized into three primary clusters: genes upregulated early in the time course, genes upregulated during matrix formation, and genes downregulated during matrix formation. Genes were then grouped based on function and/or signaling pathways. Many gene groups known to be important in loading-induced bone formation were identified within the clusters, including AP-1-related genes in the early response cluster, matrix-related genes in the upregulated gene clusters, and Wnt/?-catenin signaling pathway inhibitors in the downregulated gene clusters. Several novel gene groups were identified as well, including chemokine-related genes which were upregulated early but downregulated later in the time course, solute carrier genes which were both up- and downregulated, and muscle-related genes which were primarily downregulated. Time Course with 11 time points, each plus & minus mechanical stimulation with 5 replicates per experimental group (except 12d group which has 4 replicates). Daily mechanical loading was applied to the forearm (24 hours between loading sessions), and ulnae were sampled at indicated time points (4h, 12h, 1d, 2d, 4d, 6d, 8d, 12d, 16d, 24d, or 32d).
Project description:Dermal fibroblasts deposit type I collagen, the dominant extracellular matrix molecule found in skin, during early postnatal development. Coincident with this biosynthetic program, fibroblasts proteolytically remodel pericellular collagen fibrils by mobilizing the membrane-anchored matrix metalloproteinase, Mmp14. Unexpectedly, dermal fibroblasts in Mmp14-/- mice commit to a large-scale apoptotic program that leaves skin tissues replete with dying cells. A requirement for Mmp14 in dermal fibroblast survival is recapitulated in vitro when cells are embedded within, but not cultured atop, 3-dimensional hydrogels of cross-linked type I collagen. In the absence of Mmp14-dependent pericellular proteolysis, dermal fibroblasts fail to trigger β1 integrin activation and instead actuate a TGF-β1/phospho-JNK stress response that leads to apoptotic cell death in vitro as well as in vivo. Taken together, these studies identify Mmp14 as a requisite cell survival factor that maintains dermal fibroblast viability in postnatal dermal tissues.
Project description:The objective of our study was to use a microarray to distinguish the molecular responses between woven and lamellar bone formation induced through mechanical loading. The micorarray identified numerous genes and pathways that were differentially regulated for woven, but not lamellar bone formation. Rat forelimb loading was completed in a single bout to induce the formation of woven bone (WBF loading) or lamellar bone (LBF loading). A set of normal (non-loaded) rats were used as controls. Microarrays were performed at three timepoints after loading: 1 hr, 1 day and 3 days.
Project description:The advent of high-throughput measurements of gene expression and bioinformatics analysis methods offers new ways to study gene expression patterns. The primary goal of this study was to determine the time sequence for gene expression in a bone subjected to mechanical loading, during key periods of the bone formation process, including expression of matrix-related genes, the appearance of active osteoblasts, and bone desensitization. A standard model for bone loading was employed in which the right forelimb was loaded axially for three minutes per day, while the left forearm served as a non-loaded, contralateral control. We evaluated loading-induced gene expression over a time course of 4 hours to 32 days after the first loading session. Six distinct, time-dependent patterns of gene expression were identified over the time course and categorized into three primary clusters: genes upregulated early in the time course, genes upregulated during matrix formation, and genes downregulated during matrix formation. Genes were then grouped based on function and/or signaling pathways. Many gene groups known to be important in loading-induced bone formation were identified within the clusters, including AP-1-related genes in the early response cluster, matrix-related genes in the upregulated gene clusters, and Wnt/β-catenin signaling pathway inhibitors in the downregulated gene clusters. Several novel gene groups were identified as well, including chemokine-related genes which were upregulated early but downregulated later in the time course, solute carrier genes which were both up- and downregulated, and muscle-related genes which were primarily downregulated.
Project description:Skeletal integrity in humans and animals is maintained by daily mechanical loading. It has been widely accepted that osteocytes function as mechanosensors. Many biochemical signaling molecules are involved in the response of osteocytes to mechanical stimulation. The aim of this study was to identify genes involved in the translation of mechanical stimuli into bone formation. The four-point bending model was used to induce a single period of mechanical loading (comprising 300 cycles (2 Hz) using a peak magnitude of 60 N) on the right tibia, while the contra lateral left tibia served as control. Six hours after loading, the effects of mechanical loading on gene-expression were determined with microarray analysis. Protein expression of differentially regulated genes was evaluated with immunohistochemistry. Nine genes were found to exhibit a significant differential gene expression in LOAD compared to control. MEPE, Garnl1, V2R2B, and QFG TN1 olfactory receptor were up-regulated, and creatine kinase (muscle form), fibrinogen-B beta-polypeptide, monoamine oxidase A, troponin-C and kinesin light chain-C were down-regulated. Validation with real-time RT-PCR analysis confirmed the up regulation of MEPE and the down-regulation of creatine kinase (muscle form) and troponin-C in the loaded tibia. Immunohistochemistry showed that the increase of MEPE protein expression was already detectable six hours after mechanical loading. In conclusion, these genes probably play a role during translation of mechanical stimuli six hours after mechanical loading. The modulation of MEPE expression may indicate a connection between bone mineralization and bone formation after mechanical stimulation. Two groups: LOAD vs contralateral control and SHAM vs contralateral control (n=5/group)