Phenotypic maintenance of articular chondrocytes in vitro requires BMP activity

2007 ◽  
Vol 20 (03) ◽  
pp. 185-191 ◽  
Author(s):  
A. O. Oshin ◽  
E. Caporali ◽  
C. R. Byron ◽  
A. A. Stewart ◽  
M. C. Stewart

SummaryArticular chondrocytes are phenotypically unique cells that are responsible for the maintenance of articular cartilage. The articular chondrocytic phenotype is influenced by a range of soluble factors. In particular, members of the bone morphogenetic protein (BMP) family support the articular chondrocytic phenotype and stimulate synthesis of cartilaginous matrix. This study was carried out to determine the importance of BMPs in supporting the differentiated phenotype of articular chondrocytes in vitro. Exogenous BMP-2 supported expression of collagen type II and aggrecan in monolayer chondrocyte cultures, slowing the dedifferentiation process that occurs under these conditions. In contrast, BMP-2 had little effect on expression of these genes in three-dimensional aggregate cultures. Endogenous BMP-2 expression was lost in monolayer cultures, coincident with the down-regulation of collagen type II and aggrecan mRNAs, whereas BMP-2 mRNA levels were stable in aggregate cultures. Antagonism of endogenous BMP activity in aggregate cultures by Noggin or a soluble form of the BMP receptor resulted in reduced expression of collagen type II and aggrecan mRNAs, reduced collagen type II protein and sulfated glycosaminoglycan (GAG) deposition into the aggregate matrices and reduced secretion of GAGs into the culture media. These results indicate that endogenous BMPs are required for maintenance of the differentiated articular chondrocytic phenotype in vitro. These findings are of importance to cell-based strategies designed to repair articular cartilage. Articular chondrocytes require conditions that will support endogenous expression of BMPs to maintain the specialized phenotype of these cells.

2019 ◽  
Vol 20 (4) ◽  
pp. 795 ◽  
Author(s):  
Ufuk Tan Timur ◽  
Marjolein Caron ◽  
Guus van den Akker ◽  
Anna van der Windt ◽  
Jenny Visser ◽  
...  

During standard expansion culture (i.e., plasma osmolarity, 280 mOsm) human articular chondrocytes dedifferentiate, making them inappropriate for autologous chondrocyte implantation to treat cartilage defects. Increasing the osmolarity of culture media to physiological osmolarity levels of cartilage (i.e., 380 mOsm), increases collagen type II (COL2A1) expression of human articular chondrocytes in vitro, but the underlying molecular mechanism is not fully understood. We hypothesized that TGF-β superfamily signaling may drive expression of COL2A1 under physiological osmolarity culture conditions. Human articular chondrocytes were cultured in cytokine-free medium of 280 or 380 mOsm with or without siRNA mediated TGF-β2 knockdown (RNAi). Expression of TGF-β isoforms, and collagen type II was evaluated by RT-qPCR and immunoblotting. TGF-β2 protein secretion was evaluated using ELISA and TGF-β bioactivity was determined using an established reporter assay. Involvement of BMP signaling was investigated by culturing human articular chondrocytes in the presence or absence of BMP inhibitor dorsomorphin and BMP bioactivity was determined using an established reporter assay. Physiological cartilage osmolarity (i.e., physosmolarity) most prominently increased TGF-β2 mRNA expression and protein secretion as well as TGF-β bioactivity. Upon TGF-β2 isoform-specific knockdown, gene expression of chondrocyte marker COL2A1 was induced. TGF-β2 RNAi under physosmolarity enhanced TGF-β bioactivity. BMP bioactivity increased upon physosmotic treatment, but was not related to TGF-β2 RNAi. In contrast, dorsomorphin inhibited COL2A1 mRNA expression in human articular chondrocytes independent of the osmotic condition. Our data suggest a role for TGF-β superfamily member signaling in physosmolarity-induced mRNA expression of collagen type II. As physosmotic conditions favor the expression of COL2A1 independent of our manipulations, contribution of other metabolic, post-transcriptional or epigenetic factors cannot be excluded in the underlying complex and interdependent regulation of marker gene expression. Dissecting these molecular mechanisms holds potential to further improve future cell-based chondral repair strategies.


2008 ◽  
Vol 14 (12) ◽  
pp. 1999-2007 ◽  
Author(s):  
Aboulghassem Shahdadfar ◽  
Sverre Løken ◽  
John Arne Dahl ◽  
Siv H. Tunheim ◽  
Philippe Collas ◽  
...  

Author(s):  
Cornelius Cano Ssemakalu ◽  
Mapula Razwinani ◽  
Makwese Johannes Maepa ◽  
Keolebogile Shirley Motaung

2007 ◽  
Vol 15 ◽  
pp. B67
Author(s):  
A. Shahdadfar ◽  
S. Løken ◽  
S.H. Tunheim ◽  
J.B. Eriksen ◽  
J.A. Dahl ◽  
...  

2000 ◽  
Vol 18 (4) ◽  
pp. 524-531 ◽  
Author(s):  
Tokifumi Majima ◽  
Linda L. Marchuk ◽  
Paul Sciore ◽  
Nigel G. Shrive ◽  
Cyril B. Frank ◽  
...  

2018 ◽  
Vol 9 ◽  
pp. 204173141878982 ◽  
Author(s):  
Elisa Costa ◽  
Cristina González-García ◽  
José Luis Gómez Ribelles ◽  
Manuel Salmerón-Sánchez

Articular chondrocytes are difficult to grow, as they lose their characteristic phenotype following expansion on standard tissue culture plates. Here, we show that culturing them on surfaces of poly(L-lactic acid) of well-defined microtopography allows expansion and maintenance of characteristic chondrogenic markers. We investigated the dynamics of human chondrocyte dedifferentiation on the different poly(L-lactic acid) microtopographies by the expression of collagen type I, collagen type II and aggrecan at different culture times. When seeded on poly(L-lactic acid), chondrocytes maintained their characteristic hyaline phenotype up to 7 days, which allowed to expand the initial cell population approximately six times without cell dedifferentiation. Maintenance of cell phenotype was afterwards correlated to cell adhesion on the different substrates. Chondrocytes adhesion occurs via the α5 β1 integrin on poly(L-lactic acid), suggesting cell–fibronectin interactions. However, α2 β1 integrin is mainly expressed on the control substrate after 1 day of culture, and the characteristic chondrocytic markers are lost (collagen type II expression is overcome by the synthesis of collagen type I). Expanding chondrocytes on poly(L-lactic acid) might be an effective solution to prevent dedifferentiation and improving the number of cells needed for autologous chondrocyte transplantation.


2009 ◽  
Vol 18 (8) ◽  
pp. 923-932 ◽  
Author(s):  
Martin Jung ◽  
Balazs Kaszap ◽  
Anna Redöhl ◽  
Eric Steck ◽  
Steffen Breusch ◽  
...  

Adult mesenchymal stem cells (MSCs) are an attractive cell source for new treatment strategies in regenerative medicine. This study investigated the potential effect of matrix assisted MSC transplantation for articular cartilage regeneration in a large-animal model 8 weeks postoperatively. MSCs from bone marrow aspirates of eight Goettingen minipigs were isolated and expanded prior to surgery. Articular cartilage defects of 5.4 mm were created bilaterally in the medial patellar groove without penetrating the subchondral bone plate. Defects were either left empty ( n = 4), covered with a collagen type I/III membrane ( n = 6) or additionally treated with autologous MSC transplantation (2 × 106; n = 6). After 8 weeks animals were euthanized and the defect area was assessed for its gross appearance. Histomorphological analysis of the repair tissue included semiquantitative scoring (O'Driscoll score) and quantitative histomorphometric analysis for its glycosaminoglycan (GAG) and collagen type II content. All membranes were found to cover the defect area 8 weeks postoperatively. Median defect filling was 115.8% (membrane), 117.8% (empty), and 100.4% (MSC), respectively (not significant). Histomorphological scoring revealed significantly higher values in MSC-treated defects (median 16.5) when compared to membrane treatment (median 9.5) or empty defects (median 11.5; p = 0.015 and p = 0.038). Histomorphometric analysis showed larger GAG/collagen type II-positive areas in the MSC-treated group (median 24.6%/29.5% of regeneration tissue) compared to 13.6%/33.1% (empty defects) and 1.7%/6.2% (membrane group; p = 0.066). Cell distribution was more homogeneous in MSC compared to membrane-only group, where cells were found mainly near the subchondral zone. In conclusion, autologous matrix-assisted MSC transplantation significantly increased the histomorphological repair tissue quality during early articular cartilage defect repair and resulted in higher GAG/collagen type II-positive cross-sectional areas of the regenerated tissue.


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