Project description:Pathological processes like osteoporosis or steroid-induced osteonecrosis of the hip are accompanied by increased bone marrow adipogenesis. Such disorder of adipogenic/osteogenic differentiation, which affects also bone marrow derived mesenchymal stem cells (BMSCs) contributes to bone loss during aging. Therefore, we investigated the effects of extracellular vesicles (EVs) isolated from human (h)BMSCs during different stages of osteogenic differentiation on osteogenic and adipogenic differentiation capacity of naïve hBMSCs.
Project description:Gene Expression analysis of a differentiation timeseries of human Mesenchymal Stem Cells (hMSCs) in the presence of adipogenic/osteogenic factors. hMSCs differentiate into fat cells when treated with dexamethasone (10^-6 M), insulin (10 ug/ml), rosiglitazone (10^-7 M) and IBMX (250 uM). TGFbeta (5 ng/ml) inhibits this process and redirects these cells to differentiate into bone cells. Introduction: Patients suffering from osteoporosis show an increased number of adipocytes in their bone marrow, concomitant with a reduction in the pool of human mesenchymal stem cells (hMSCs) that are able to differentiate into osteoblasts, thus leading to suppressed osteogenesis. Methods: In order be able to interfere with this process, we have investigated in vitro culture conditions whereby adipogenic differentiation of hMSCs is impaired and osteogenic differentiation is promoted. By means of gene expression microarray analysis, we have investigated genes which are potential targets for prevention of fat cell differentiation. Results: Our data show that BMP2 promotes both adipogenic and osteogenic differentiation of hMSCs, while TGFβ inhibits differentiation into both lineages. However, when cells are cultured under adipogenic differentiation conditions, which contains cAMP-enhancing agents such as IBMX of PGE2, TGFβ promotes osteogenic differentiation, while at the same time inhibiting adipogenic differentiation. Gene expression and immunoblot analysis indicated that cAMP-induced suppression of HDAC5 levels plays an important role in the inhibitory effect of TGFβ on osteogenic differentiation. By means of gene expression microarray analysis, we have investigated genes which are downregulated by TGFβ under adipogenic differentiation conditions and may therefore be potential targets for prevention of fat cell differentiation. We thus identified 9 genes for which FDA-approved drugs are available. Our results show that drugs directed against the nuclear hormone receptor PPARG, the metalloproteinase ADAMTS5 and the aldo-keto reductase AKR1B10 inhibit adipogenic differentiation in a dose-dependent manner, although in contrast to TGFβ they do not appear to promote osteogenic differentiation. Conclusions: The approach chosen in this study has resulted in the identification of new targets for inhibition of fat cell differentiation, which may not only be relevant for prevention of osteoporosis, but also of obesity. hMSCs were induced to differentiate in the presence dexamethasone, insulin and rosiglitazone, to which was added either 50 ng/ml BMP2; BMP2 + TGFbeta; BMP2 + IBMX; BMP2 + TGFbeta + IBMX.
Project description:Gene Expression analysis of a differentiation timeseries of human Mesenchymal Stem Cells (hMSCs) in the presence of adipogenic/osteogenic factors. hMSCs differentiate into fat cells when treated with dexamethasone (10^-6 M), insulin (10 ug/ml), rosiglitazone (10^-7 M) and IBMX (250 uM). TGFbeta (5 ng/ml) inhibits this process and redirects these cells to differentiate into bone cells. Introduction: Patients suffering from osteoporosis show an increased number of adipocytes in their bone marrow, concomitant with a reduction in the pool of human mesenchymal stem cells (hMSCs) that are able to differentiate into osteoblasts, thus leading to suppressed osteogenesis. Methods: In order be able to interfere with this process, we have investigated in vitro culture conditions whereby adipogenic differentiation of hMSCs is impaired and osteogenic differentiation is promoted. By means of gene expression microarray analysis, we have investigated genes which are potential targets for prevention of fat cell differentiation. Results: Our data show that BMP2 promotes both adipogenic and osteogenic differentiation of hMSCs, while TGFβ inhibits differentiation into both lineages. However, when cells are cultured under adipogenic differentiation conditions, which contains cAMP-enhancing agents such as IBMX of PGE2, TGFβ promotes osteogenic differentiation, while at the same time inhibiting adipogenic differentiation. Gene expression and immunoblot analysis indicated that cAMP-induced suppression of HDAC5 levels plays an important role in the inhibitory effect of TGFβ on osteogenic differentiation. By means of gene expression microarray analysis, we have investigated genes which are downregulated by TGFβ under adipogenic differentiation conditions and may therefore be potential targets for prevention of fat cell differentiation. We thus identified 9 genes for which FDA-approved drugs are available. Our results show that drugs directed against the nuclear hormone receptor PPARG, the metalloproteinase ADAMTS5 and the aldo-keto reductase AKR1B10 inhibit adipogenic differentiation in a dose-dependent manner, although in contrast to TGFβ they do not appear to promote osteogenic differentiation. Conclusions: The approach chosen in this study has resulted in the identification of new targets for inhibition of fat cell differentiation, which may not only be relevant for prevention of osteoporosis, but also of obesity.
Project description:Osteogenic differentiation of human mesenchymal stromal cells (hMSCs) may potentially be used in cell-based bone tissue-engineering applications to enhance the bone-forming potential of these cells. Osteogenic differentiation and adipogenic differentiation are thought to be mutually exclusive, and although several signaling pathways and cues that induce osteogenic or adipogenic differentiation, respectively, have been identified, there is no general consensus on how to optimally differentiate hMSCs into the osteogenic lineage. Some pathways have also been reported to be involved in both adipogenic and osteogenic differentiation, as for example, the protein kinase A (PKA) pathway, and the aim of this study was to investigate the role of cAMP/PKA signaling in differentiation of hMSCs in more detail. We show that activation of this pathway with dibutyryl-cAMP results in enhanced alkaline phosphatase expression, whereas another cAMP analog induces adipogenesis in long-term mineralization cultures. Adipogenic differentiation, induced by 8-bromo-cAMP, was accompanied by stronger PKA activity and higher expression of cAMP-responsive genes, suggesting that stronger activation correlates with adipogenic differentiation. In addition, a whole-genome expression analysis showed an increase in expression of adipogenic genes in 8-br-cAMP-treated cells. Furthermore, by means of quantitative polymerase chain reaction, we show differences in peroxisome proliferator-activated receptor-gamma activation, either alone or in combination with dexamethasone, thus demonstrating differential effects of the PKA pathway, most likely depending on its mode of activation.
Project description:Global gene expression data of human embryonic stem cell-, human induced pluripotent stem cell- and bone marrow-derived mesenchymal progenitor cells before and after culture onto osteoinductive scaffolds in perfusion bioreactors. The hypothesis tested in the present study was that perfusion culture in bioreactors influenced the expression levels of several genes involved in proliferation and osteogenic differentiation. Results provide important information of the response of human embryonic stem cell-, human induced pluripotent stem cell- and bone marrow-derived mesenchymal progenitor cell to osteogenic stimulation under perfusion cultures, such as genes involved in cell proliferation and division as well as osteogenic differentiation and bone development. Total RNA obtained from human embryonic stem cell-, human induced pluripotent stem cell- and bone marrow-derived mesenchymal progenitor cells before and after culture under osteogenic conditions in perfusion bioreactors for 5 weeks.
Project description:Schittler2010 - Cell fate of progenitor cells, osteoblasts or chondrocytes
Mathematical model describing the mechanism of differentiation of mesenchymal stem cells to bone (osteoblasts) or cartilage (chondrocytes) cells.
This model is described in the article:
Cell differentiation modeled via a coupled two-switch regulatory network.
Schittler D, Hasenauer J, Allgöwer F, Waldherr S.
Chaos 2010 Dec; 20(4): 045121
Abstract:
Mesenchymal stem cells can give rise to bone and other tissue cells, but their differentiation still escapes full control. In this paper we address this issue by mathematical modeling. We present a model for a genetic switch determining the cell fate of progenitor cells which can differentiate into osteoblasts (bone cells) or chondrocytes (cartilage cells). The model consists of two switch mechanisms and reproduces the experimentally observed three stable equilibrium states: a progenitor, an osteogenic, and a chondrogenic state. Conventionally, the loss of an intermediate (progenitor) state and the entailed attraction to one of two opposite (differentiated) states is modeled as a result of changing parameters. In our model in contrast, we achieve this by distributing the differentiation process to two functional switch parts acting in concert: one triggering differentiation and the other determining cell fate. Via stability and bifurcation analysis, we investigate the effects of biochemical stimuli associated with different system inputs. We employ our model to generate differentiation scenarios on the single cell as well as on the cell population level. The single cell scenarios allow to reconstruct the switching upon extrinsic signals, whereas the cell population scenarios provide a framework to identify the impact of intrinsic properties and the limiting factors for successful differentiation.
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Project description:In this study, we proved the exercise-induced promotion of osteogenic differentiation and inhibition of adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) through establishing exercise animal model by treadmill running experiment. miRNA sequencing analysis identified 16 upregulated and 2 downregulated miRNAs in exercise group.
Project description:In this study, we proved the exercise-induced promotion of osteogenic differentiation and inhibition of adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) through establishing exercise animal model by treadmill running experiment. lncRNA sequencing analysis identified 44 upregulated lncRNAs and 39 downregulated lncRNAs in exercise group.
Project description:Adipose-derived and bone-marrow-derived mesenchymal stem cells were collected from 3 pigs and cultivated in vitro up to 3 passages. At passage 3 cells were cultured to 80% confluence and induced to differentiate in adipose and bone. Cell were harvested at 0 day of differentiation (dd) or pre-differentiation, at 2, 7, and 21dd for RNA extraction. The RNA was used for a large microarray analysis using a specific pig oligo-array with >10,000 annotated genes. The main aim of the microarray analysis was to directly compare the two transcriptomics adaptation of the two mesenchymal stem cells during osteogenic and adipogenic differentiation The mesenchymal stem cells were harvested at 0, 2, 7, and 21 day of differentiation (dd). A dye-swap reference design (reference = mixture of RNA from several porcine tissues) was used.
Project description:Extracellular nucleotides are potent signaling molecules mediating cell-specific biological functions. We previously demonstrated that adenosine 5'-triphosphate (ATP) inhibits the proliferation while stimulating the migration, in vitro and in vivo, of human bone marrow-derived mesenchymal stem cells (BM-hMSC). Here, we investigated the effects of ATP on BM-hMSC differentiation capacity. Molecular analysis showed that ATP treatment modulated the expression of several genes (e.g. wnt-pathway-related genes) governing osteoblastic and adipogenic differentiation of MSCs. Functional studies demonstrated that ATP, under specific culture conditions, stimulated adipogenic and osteogenic differentiation by significantly increasing the lipid accumulation and the expression levels of the adipogenic master gene PPARγ (peroxisome proliferator activated receptor-gamma) and by promoting the mineralization and the expression of the osteoblast-related gene RUNX2 (Runt-related transcription factor 2), respectively. BM-hMSCs cells were transiently exposed to ATP 1mM for 24 hours (ATP pre-treatment) before starting differentiation induction. Then, BM-hMSCs were cultured under adipogenic/osteogenic conditions. Gene Expression Profile was performed on differentiate cells after 3 weeks of induction culture.