Effects of L-BAIBA administration and sub-optimal mechanical loading on gene expression in osteocyte-enriched cortical bone
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE214582 | GEO | 2023/02/01
REPOSITORIES: GEO
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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.
2013-01-01 | E-GEOD-27065 | biostudies-arrayexpress
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)
2013-11-21 | E-GEOD-50707 | biostudies-arrayexpress
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.
2013-11-21 | GSE50707 | GEO
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).
2010-06-12 | E-GEOD-22286 | biostudies-arrayexpress
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.
2010-11-01 | E-GEOD-18879 | biostudies-arrayexpress
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).
2010-11-01 | GSE18879 | GEO
Project description:Osteoporosis affects over 200 million women worldwide, one third of whom are predicted to suffer from an osteoporotic fracture in their lifetime. The most promising anabolic drugs involve administration of expensive antibodies. Because mechanical loading stimulates bone formation, our current data, using a mouse model, replicates the anabolic effects of loading in humans and may identify novel pathways amenable to oral treatment. Murine tibial compression produces axially-varying deformations along the cortical bone, inducing highest strains at the mid-diaphysis and lowest at the metaphyseal shell. To test the hypothesis that load-induced transcriptomic responses at different axial locations of cortical bone would vary as a function of strain magnitude, we loaded the left tibiae of 10wk female C57Bl/6 mice in vivo in compression, with contralateral limbs as controls. Animals were euthanized at 1, 3 or 24 h post-loading or loaded for 1 wk (n=4-5/group). Bone marrow and cancellous bone were removed, cortical bone was segmented into the metaphyseal shell, proximal diaphysis and mid-diaphysis, and load-induced differential gene expression and enriched biological processes were examined for the three segments. At each time point, the mid-diaphysis (highest strain) had the greatest transcriptomic response. Similarly, biological processes regulating bone formation and turnover increased earlier and to the greatest extent at the mid-diaphysis. Higher strain induced greater levels of osteoblast and osteocyte genes, whereas expression was lower in osteoclasts. Among the top differentially-expressed genes at 24-hours post-loading, seventeen had known functions in bone biology, of which twelve were present only in osteoblasts, three exclusively in osteoclasts, and two were present in both cell types. Based on these results, we conclude that murine tibial loading induces spatially-unique transcriptomic responses correlating with strain magnitude in cortical bone.
2022-08-12 | GSE210827 | GEO
Project description:Studies from global loss-of-function mutants suggest that alternative NF-kB downstream of NF-kB inducing kinase (NIK) is a cell-intrinsic negative regulator of osteogenesis. However, the interpretation of the osteoblast and/or osteocyte contribution to the bone phenotype is complicated by simultaneous osteoclast defects in these models. Therefore, we turned to a transgenic mouse model to investigate the direct role of NIK in the osteolineage. Osx-Cre;NT3 animals (NT3-Cre+), which bear a constitutively active NIK allele (NT3) driven by Osx-Cre, were compared to their Cre-negative, Control (Ctrl) littermates. NT3-Cre+ mice had elevated serum P1NP and CTX levels. Despite this high turnover state, microCT showed that constitutive activation of NIK resulted in a net increase in basal bone mass in both cortical and cancellous compartments. Furthermore, NT3-Cre+ mice exhibited a greater anabolic response following mechanical loading compared to controls. We next performed RNA-Seq on non-loaded and loaded tibiae to elucidate possible mechanisms underlying the increased bone anabolism seen in NT3-Cre+ mice. Hierarchical clustering revealed two main transcriptional programs: one loading-responsive and the other NT3 transgene-driven. Gene ontology (GO) analysis indicated a distinct upregulation of receptor, kinase and growth factor activities including Wnts, as well as a calcium-response signature in NT3-Cre+ limbs. The promoters of these GO-term associated genes, including many known to be bone-anabolic, were highly enriched for multiple kB recognition elements (kB-RE) relative to the background frequency in the genome. The loading response in NT3-Cre+ mice substantially overlapped (>90%) with Ctrl. Surprisingly, control animals had 10-fold more differentially expressed genes (DEGs) in response to loading. However, most top DEGs shared between genotypes had a high incidence of multiple kB-RE in their promoters. Therefore, both transcriptional programs (loading-responsive and NT3 transgene-driven) are modulated by NF-kB. Our studies uncover a previously unrecognized role for NF-kB in the promotion of both basal and mechanically-stimulated bone formation.
2019-06-25 | GSE133212 | GEO
Project description:Osteocytes are long-lived, highly interconnected, terminally differentiated osteoblasts which reside within mineralized bone matrix. They constitute about 95% of adult bone cells and play important functions in the regulation of bone remodeling, phosphate homeostasis, and mechanical stimuli sensing and response. However, the role of osteocytes in the pathogenesis of congenital diseases of bone such as osteogenesis imperfecta (OI) is poorly understood. This study characterized in vivo transcriptional changes in osteocytes from the CrtapKO and oim/oim mouse models of OI, using RNA-sequencing on osteocyte-enriched cortical bone from femur and tibia. These models were chosen because they mimic two types of OI with different genetic mutations which result in distinct type I collagen defects. Hundreds of transcripts were dysregulated in either model of OI compared to WT, but 281 of these were similarly up- or down-regulated in both. Conversely, very few transcripts were differentially expressed between the CrtapKO and oim/oim mice, indicating that distinct alterations in type I collagen can lead to shared pathogenic processes and similar phenotypic outcomes. Bioinformatics analyses identified several critical hubs of dysregulation that were enriched in annotation terms such as development and differentiation, ECM and collagen fibril organization, cell adhesion, signaling, regulatory processes, pattern binding, chemotaxis, and cell projections. The data further indicated alterations in important signaling pathways such as WNT and TGF-β. Overall, our study suggested that the osteocyte transcriptome is broadly dysregulated in OI, that transcriptomic alterations in OI can be strikingly similar despite arising from different genetic mutations, and that the potential consequences of osteocyte dysregulation deserve further investigation.
2020-07-21 | GSE154748 | GEO
Project description:A unique experimental rat ICU model has been used allowing long-term (weeks) time-resolved analyses of the effects of standardized unilateral passive mechanical loading on skeletal muscle size and function and underlying mechanisms. Results show that passive mechanical loading alleviated the muscle wasting and the loss of force-generation associated with the ICU intervention, resulting in a doubling of the functional capacity of the loaded versus the unloaded muscles after a 2-week ICU intervention.
2015-05-14 | ST000165 | MetabolomicsWorkbench