Project description:The recruitment of mesenchymal stem cells in order to reconstruct damaged cartilage of osteoarthritis joints is a challenging tissue engineering task. Vision towards this goal is blurred by a lack of knowledge about the underlying differences between chondrocytes and MSC during the chondrogenic cultivation process. The aim of this study was to shed light on the differences between chondrocytes and MSC occurring during chondral differentiation through tissue engineering. As a model we used the pellet culture system under chondrogenic conditions for the comparison of chondrocyte and MSC differentiation. Immunohistology was followed by microarray analysis, which was filtered through already published datasets describing different developmental processes. Validation was performed with quantitative RT-PCR. Results describe inferior chondrogenic ECM-production by MSCs and underline their closer link to the osteogenic lineage. Chondrocytes have an upregulated fatty acid/cholesterol metabolism which might give hints for future modifications of culture conditions. To shed light on the differences between chondrocytes and MSC occurring during chondral differentiation through tissue engineering, a pellet culture system under chondrogenic conditions for the comparison of chondrocyte and MSC differentiation was used after 0, 3, 7 and 14 days
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:Objective: Assuming that mesenchymal stem cells adapt to the osteoarthritic joint environment to exert a chondroprotective effect, we aimed at investigating the molecular response set up by MSCs after priming by OA chondrocytes in cocultures. Design: We used primary human OA chondrocytes and adipose stem cells (ASCs) in mono- and cocultures and performed a high throughput secretome analysis. Among secreted proteins differentially induced in cocultures, we identified thrombospondin-1 (THBS1) as a potential candidate that could be involved in the chondroprotective effect of ASCs. Results: Secretome analysis revealed significant induction of THBS1in ASCs/chondrocytes cocultures at the mRNA and protein levels. Interestingly, we showed that THBS1 was up-regulated at late stages of MSC chondrogenic differentiation while recombinant THBS1 exerted a prochondrogenic effect on MSC. However, down-regulation of THBS1 in ASCs did not revert OA chondrocyte phenotype by decreasing hypertrophic and inflammatory markers. Nevertheless, down-regulation of THBS1 in ASCs reduced their immunosuppressive activity while recombinant THBS1 exerted an anti-inflammatory role on T lymphocytes. THBS1 function was evaluated in vivo in the collagenase-induced OA (CIOA) model by comparing ASCs expressing siTHBS1 and control ASCs. The OA protective effect of ASCs was reversed when THBS1 was down-regulated in ASCs indicating that THBS1 plays a role in the therapeutic effect of ASCs Conclusions: Our data gather some evidence that THBS1 exerts a pro-chondrogenic and anti-inflammatory function in vitro, which could partially explain a chondroprotective effect of ASCs in OA.
Project description:The recruitment of mesenchymal stem cells in order to reconstruct damaged cartilage of osteoarthritis joints is a challenging tissue engineering task. Vision towards this goal is blurred by a lack of knowledge about the underlying differences between chondrocytes and MSC during the chondrogenic cultivation process. The aim of this study was to shed light on the differences between chondrocytes and MSC occurring during chondral differentiation through tissue engineering. As a model we used the pellet culture system under chondrogenic conditions for the comparison of chondrocyte and MSC differentiation. Immunohistology was followed by microarray analysis, which was filtered through already published datasets describing different developmental processes. Validation was performed with quantitative RT-PCR. Results describe inferior chondrogenic ECM-production by MSCs and underline their closer link to the osteogenic lineage. Chondrocytes have an upregulated fatty acid/cholesterol metabolism which might give hints for future modifications of culture conditions.
Project description:Regeneration of human cartilage is inherently inefficient; an abundant autologous source like human induced pluripotent stem cells (hiPSC) is therefore attractive for engineering cartilage. Here, we report a defined growth factor based protocol for differentiating hiPSC into articular-like chondrocytes within two weeks with a high efficiency. The hiPSC-derived chondrocytes (hiChondrocytes) are stable and comparable to adult articular chondrocytes in global gene expression, extracellular matrix production and in their ability to generate cartilage tissue in vitro and in immune-deficient mice. Molecular characterization identified an early Sox9lowCD44lowCD140low pre-chondrogenic mesodermal population during hiPSC differentiation that eventually generates a homogenous population of Sox9highCD44highCD140high hiChondrocytes. Additionally, global gene expression analyses revealed two distinct Sox9-regulated gene networks in the Sox9low and Sox9high populations providing novel molecular insights into chondrogenic fate commitment and differentiation. Our findings present a favorable method for generation of hiPSC-derived articular chondrocytes in terms of safety and efficiency. 10 samples were analysed (duplicate sets of 5 time points) to assess changing gene expression over the course of differentiation from iPSC to hiChondrocyte. All samples were compared relative to the undifferentiated iPSC. Adult chondrocytes (2 samples) were also included for comparison. We analyzed the changes in gene expression with differentiation; genes with a fold-change â?¥ or â?¤1.5, with a difference in intensity of >100 and within the lower 90% confidence bound were selected.
Project description:Bovine chondrocyte-seeded and mesenchymal stem cell (MSC)-seeded agarose were cultured for 28 days in chemically defined media containing 10 ng/mL TGF-beta3. Chondrogenic differentiated MSCs were compared to chondrocytes at this timepoint and to undifferentiated MSCs harvested at day 0. Donor-matched sets of chondrocytes and MSCs were used, with three donors total.
Project description:Fibroblast growth factor-2 delays the loss of chondrogenic potential in adult bone marrow-derived mesenchymal stem cells; We compared human mesenchymal stem cells (hMSCs), expanded long-term with and without fibroblast growth factor (FGF) supplementation, with respect to their proliferation rate, and ability to differentiate along the chondrogenic pathway in vitro. hMSCs expanded in FGF-supplemented medium proliferated more rapidly than those expanded under control conditions. Aggregates of FGF-treated cells exhibited chondrogenic differentiation at passages 1 through 7, although, in some of the preparations, chondrogenic differentiation was somewhat diminished after seventh passage. Aggregates made with control cells differentiated along the chondrogenic lineage at first passage but exhibited only marginal chondrogenic differentiation after four passages and failed to form cartilage after seven passages. Microarray analysis of gene expression identified 334 transcripts that were differentially expressed in fourth passage control cells which had reduced chondrogenic potential compared to fourth passage FGF-treated cells which retained this differentiation capacity and 243 transcripts that were differentially expressed when comparing them to first passage control cells which were also capable of differentiating into chondrocytes. The intersection of these analyses yielded 49 transcripts that were differentially expressed in cells that exhibited chondrogenic differentiation in vitro compared to cells that did not. These preliminary data must now be validated to verify whether the different gene expression profiles translate into functional differences. These findings suggest that care should be exercised when extensively expanding these cells for cartilage tissue engineering applications. Experiment Overall Design: hMSCs from three different donors were expanded for up to seven passages with or without FGF supplementation. At the end of first, fourth and seventh passages the chondrogenic potential and gene expression progfiles were analyzed.
Project description:We used human fetal bone marrow-derived mesenchymal stromal cells (hfMSCs) differentiating towards chondrocytes as an alternative model for the human growth plate (GP). Our aims were to study gene expression patterns associated with chondrogenic differentiation to assess whether chondrocytes derived from hfMSCs are a suitable model for studying the development and maturation of the GP. hfMSCs efficiently formed hyaline cartilage in a pellet culture in the presence of TGFB3 and BMP6. Microarray and principal component analysis were applied to study gene expression profiles during chondrogenic differentiation. A set of 232 genes was found to correlate with in vitro cartilage formation. Several identified genes are known to be involved in cartilage formation and validate the robustness of the differentiating hfMSC model. KEGG pathway analysis using the 232 genes revealed 9 significant signaling pathways correlated with cartilage formation. To determine the progression of growth plate cartilage formation, we compared the gene expression profile of differentiating hfMSCs with previously established expression profiles of epiphyseal GP cartilage. As differentiation towards chondrocytes proceeds, hfMSCs gradually obtain a gene expression profile resembling epiphyseal GP cartilage. We visualized the differences in gene expression profiles as protein interaction clusters and identified many protein clusters that are activated during the early chondrogenic differentiation of hfMSCs showing the potential of this system to study GP development. To determine the progression of growth plate cartilage formation, we compared the gene expression profile of differentiating hfMSCs with previously established expression profiles of epiphyseal GP cartilage. As differentiation towards chondrocytes proceeds, hfMSCs gradually obtain a gene expression profile resembling epiphyseal GP cartilage. We visualized the differences in gene expression profiles as protein interaction clusters and identified many protein clusters that are activated during the early chondrogenic differentiation of hfMSCs showing the potential of this system to study GP development. RNA fhMSCs of chondrogenically differentiating fhMSCs was isolated at week, 0, 1, 2, 3, 4 and 5. Moreover, RNA of 4 human growth plates from was isolated.
Project description:Long non-coding RNAs profiling of human mesenchymal stem cells comparing undifferentiated HMSCs with differentiated HMSCs during chondrogenesis. The chondrogenic differentiation of HMSCs was induced by chondrogenic medium. The chondrogenic marker genes (Col2a1, Sox9 and ACAN) has been detected upregulating during this process by Q-PCR. The aim of this study is to determine key lncRNAs regulating the chondrogenic differentiation process.
Project description:Autologous chondrocyte transplantation (ACT) is a routine technique to regenerate focal cartilage lesions. However, patients with osteoarthritis (OA) are lacking an appropriate long-lasting treatment alternative, partly since it is not known if chondrocytes from OA patients have the same chondrogenic differentiation potential as chondrocytes from donors not affected by OA. Articular chondrocytes from patients with OA undergoing total knee replacement (Mankin Score >3, Ahlbäck Score >2) and from patients undergoing ACT, here referred to as normal donors (ND), were isolated applying protocols used for ACT. Their chondrogenic differentiation potential was evaluated both in high-density pellet and scaffold (Hyaff-11) cultures by histological proteoglycan assessment (Bern Score) and immunohistochemistry for collagen types I and II. Chondrocytes cultured in monolayer and scaffolds were subjected to gene expression profiling using genome-wide oligonucleotide microarrays. Expression data were verified by using quantitative RT-PCR. Chondrocytes from ND and OA donors demonstrated accumulation of comparable amounts of cartilage matrix components, including sulphated proteoglycans and collagen types I and II. The mRNA expression of cartilage markers (COL2A1, COMP, aggrecan, CRTL1, SOX9) and genes involved in matrix synthesis (biglycan, COL9A2, COL11A1, TIMP4, CILP2) was highly induced in 3D cultures of chondrocytes from both donor groups. Genes associated with hypertrophic or OA cartilage (COL10A1, RUNX2, periostin, ALP, PTHR1, MMP13, COL1A1, COL3A1) were not significantly regulated between the two groups of donors. The expression of 661 genes, including COMP, FN1, and SOX9, were differentially regulated between OA and ND chondrocytes cultured in monolayer. During scaffold culture, the differences diminished between the OA and ND chondrocytes, and only 184 genes were differentially regulated. Only few genes were differentially expressed between OA and ND chondrocytes in Hyaff-11 culture. The risk of differentiation into hypertrophic cartilage does not seem to be increased for OA chondrocytes. Our findings suggest that the chondrogenic capacity is not significantly affected by OA and OA chondrocytes fulfill the requirements for matrix-associated ACT. Experiment Overall Design: Gene expression profiles of monolayer cultures (ML; passage 2) and Hyaff-11 scaffold cultures (3D; 14 days in vitro) of chondrocytes from 3 normal donors (ND; underwent ACT treatment) and 3 donors suffering from Osteoarthritis (OA; underwent knee replacement surgery) were determined. Comparative analyses between 3D and ML cultures (3D vs. ML) were performed to assess differentiation capacity of ND and OA chondrocytes. Furthermore, OA-related differences were determined comparing OA and ND monolayers as well as scaffold cultures (each OA vs. ND).