Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis
Abstract Background Although mesenchymal stem/stromal cell (MSC) chondrogenic differentiation has been thoroughly investigated, the rudiments for enhancing chondrogenesis have remained largely dependent on external cues. Focus to date has been on extrinsic variables such as soluble signals, culture...
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| Format: | Article |
| Language: | English |
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BMC
2019-01-01
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| Series: | Stem Cell Research & Therapy |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13287-018-1103-y |
| _version_ | 1818443795456327680 |
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| author | Melika Sarem Oliver Otto Simon Tanaka V. Prasad Shastri |
| author_facet | Melika Sarem Oliver Otto Simon Tanaka V. Prasad Shastri |
| author_sort | Melika Sarem |
| collection | DOAJ |
| description | Abstract Background Although mesenchymal stem/stromal cell (MSC) chondrogenic differentiation has been thoroughly investigated, the rudiments for enhancing chondrogenesis have remained largely dependent on external cues. Focus to date has been on extrinsic variables such as soluble signals, culture conditions (bioreactors), and mechanical stimulation. However, the role of intrinsic mechanisms of MSC programming-based mechanobiology remains to be explored. Since aggregation of MSCs, a prerequisite for chondrogenesis, generates tension within the cell agglomerate, we inquired if the initial number of cells forming the aggregate (aggregate cell number (ACN)) can impact chondrogenesis. Methods Aggregates of varying ACN were formed using well-established centrifugation approach. Progression of chondrogenic differentiation in the aggregates was assessed over 3 weeks in presence and absence of transforming growth factor-beta 1 (TGF-β1). Mechanical properties of the cells were characterized using high-throughput real-time deformability cytometry (RT-DC), and gene expression was analyzed using Affymetrix gene array. Expression of molecular markers linked to chondrogenesis was assessed using western blot and immunofluorescence. Results Reducing ACN from 500 k to 70 k lead to activation and acceleration of the chondrogenic differentiation, independent of soluble chondro-inductive factors, which involves changes to β-catenin-dependent TCF/LEF transcriptional activity and expression of anti-apoptotic protein survivin. RT-DC analysis revealed that stiffness and size of cells within aggregates are modulated by ACN. A direct correlation between progression of chondrogenesis and emergence of stiffer cell phenotype was found. Affymetrix gene array analysis revealed a downregulation of genes associated with lipid synthesis and regulation, which could account for observed changes in cell stiffness. Immunofluorescence and western blot analysis revealed that increasing ACN upregulates the expression of lipid raft protein caveolin-1, a β-catenin binding partner, and downregulates the expression of N-cadherin. As a demonstration of the relevance of these findings in MSC-based strategies for skeletal repair, it is shown that implanting aggregates within collagenous matrix not only decreases the necessity for high cell numbers but also leads to marked improvement in the quality of the deposited tissue. Conclusions This study presents a simple and donor-independent strategy to enhance the efficiency of MSC chondrogenic differentiation and identifies changes in cell mechanics coincident with MSC chondrogenesis with potential translational applications. |
| first_indexed | 2024-12-14T19:05:43Z |
| format | Article |
| id | doaj.art-c6d7205736b6436ea4ce2e2106ee2955 |
| institution | Directory Open Access Journal |
| issn | 1757-6512 |
| language | English |
| last_indexed | 2024-12-14T19:05:43Z |
| publishDate | 2019-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Stem Cell Research & Therapy |
| spelling | doaj.art-c6d7205736b6436ea4ce2e2106ee29552022-12-21T22:50:52ZengBMCStem Cell Research & Therapy1757-65122019-01-0110111810.1186/s13287-018-1103-yCell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesisMelika Sarem0Oliver Otto1Simon Tanaka2V. Prasad Shastri3Institute for Macromolecular Chemistry, University of FreiburgCentre for Innovation Competence - Humoral Immune Response in Cardiovascular Diseases, University of GreifswaldComputational Biology Group, D-BSSE, ETH ZürichInstitute for Macromolecular Chemistry, University of FreiburgAbstract Background Although mesenchymal stem/stromal cell (MSC) chondrogenic differentiation has been thoroughly investigated, the rudiments for enhancing chondrogenesis have remained largely dependent on external cues. Focus to date has been on extrinsic variables such as soluble signals, culture conditions (bioreactors), and mechanical stimulation. However, the role of intrinsic mechanisms of MSC programming-based mechanobiology remains to be explored. Since aggregation of MSCs, a prerequisite for chondrogenesis, generates tension within the cell agglomerate, we inquired if the initial number of cells forming the aggregate (aggregate cell number (ACN)) can impact chondrogenesis. Methods Aggregates of varying ACN were formed using well-established centrifugation approach. Progression of chondrogenic differentiation in the aggregates was assessed over 3 weeks in presence and absence of transforming growth factor-beta 1 (TGF-β1). Mechanical properties of the cells were characterized using high-throughput real-time deformability cytometry (RT-DC), and gene expression was analyzed using Affymetrix gene array. Expression of molecular markers linked to chondrogenesis was assessed using western blot and immunofluorescence. Results Reducing ACN from 500 k to 70 k lead to activation and acceleration of the chondrogenic differentiation, independent of soluble chondro-inductive factors, which involves changes to β-catenin-dependent TCF/LEF transcriptional activity and expression of anti-apoptotic protein survivin. RT-DC analysis revealed that stiffness and size of cells within aggregates are modulated by ACN. A direct correlation between progression of chondrogenesis and emergence of stiffer cell phenotype was found. Affymetrix gene array analysis revealed a downregulation of genes associated with lipid synthesis and regulation, which could account for observed changes in cell stiffness. Immunofluorescence and western blot analysis revealed that increasing ACN upregulates the expression of lipid raft protein caveolin-1, a β-catenin binding partner, and downregulates the expression of N-cadherin. As a demonstration of the relevance of these findings in MSC-based strategies for skeletal repair, it is shown that implanting aggregates within collagenous matrix not only decreases the necessity for high cell numbers but also leads to marked improvement in the quality of the deposited tissue. Conclusions This study presents a simple and donor-independent strategy to enhance the efficiency of MSC chondrogenic differentiation and identifies changes in cell mechanics coincident with MSC chondrogenesis with potential translational applications.http://link.springer.com/article/10.1186/s13287-018-1103-yMechanobiologyCaveolin-1N-cadherinSurvivinMatrix metalloproteinase-2Developmental engineering |
| spellingShingle | Melika Sarem Oliver Otto Simon Tanaka V. Prasad Shastri Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis Stem Cell Research & Therapy Mechanobiology Caveolin-1 N-cadherin Survivin Matrix metalloproteinase-2 Developmental engineering |
| title | Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| title_full | Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| title_fullStr | Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| title_full_unstemmed | Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| title_short | Cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| title_sort | cell number in mesenchymal stem cell aggregates dictates cell stiffness and chondrogenesis |
| topic | Mechanobiology Caveolin-1 N-cadherin Survivin Matrix metalloproteinase-2 Developmental engineering |
| url | http://link.springer.com/article/10.1186/s13287-018-1103-y |
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