| 1. |
- Karlsson, Camilla, 1977, et al.
(författare)
-
Differentiation of human mesenchymal stem cells and articular chondrocytes: analysis of chondrogenic potential and expression pattern of differentiation-related transcription factors.
- 2007
-
Ingår i: Journal of orthopaedic research : official publication of the Orthopaedic Research Society. - : Wiley. - 0736-0266. ; 25:2, s. 152-63
-
Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stem cells (MSCs) are a candidate for replacing chondrocytes in cell-based repair of cartilage lesions. However, it has not been clarified if these cells can acquire the hyaline phenotype, and whether chondrocytes and MSCs show the same expression patterns of critical control genes in development. In order to study this, articular chondrocytes and iliac crest derived MSCs were allowed to differentiate in pellet mass cultures. Gene expression of markers for the cartilage phenotype, helix-loop-helix (HLH) transcription factors, and chondrogenic transcription factors were analyzed by real-time PCR. Matrix production was assayed using biochemical analysis for hydroxyproline, glycosaminoglycans, and immunohistochemistry for collagen types I and II. Significantly decreased expression of collagen type I was accompanied by increased expression of collagen types IIA and IIB during differentiation of chondrocytes, indicating differentiation towards a hyaline phenotype. Chondrogenesis in MSCs on the other hand resulted in up-regulation of collagen types I, IIA, IIB, and X, demonstrating differentiation towards cartilage of a mixed phenotype. Expression of HES1 increased significantly during chondrogenesis in chondrocytes while expression in MSCs was maintained at a low level. The HLH gene HES5 on the other hand was only detected in chondrocytes. Expression of ID1 decreased significantly in chondrocytes while the opposite was seen in MSCs. These findings suggest that chondrocytes and MSCs differentiated and formed different subtypes of cartilage, the hyaline and a mixed cartilage phenotype, respectively. Differentially regulated HLH genes indicated the possibility for HLH proteins in regulating chondrogenic differentiation. This information is important to understand the potential use of MSCs in cartilage repair.
|
|
| 2. |
- Karlsson, Camilla, 1977, et al.
(författare)
-
Notch and HES5 are regulated during human cartilage differentiation.
- 2007
-
Ingår i: Cell and tissue research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 327:3, s. 539-51
-
Tidskriftsartikel (refereegranskat)abstract
- The molecular mechanisms of cartilage differentiation are poorly understood. In a variety of tissues other than cartilage, members of the basic helix-loop-helix (bHLH) family of transcription factors have been demonstrated to play critical roles in differentiation. We have characterized the human bHLH gene HES5 and investigated its role during chondrogenesis. Blockage of the Notch signaling pathway with a gamma-secretase inhibitor has demonstrated that the human HES5 gene is a downstream marker of Notch signaling in articular chondrocytes. Markers for the Notch signaling pathway significantly decrease during cartilage differentiation in vitro. Cell proliferation assayed by using BrdU has revealed that blockage of Notch signaling is associated with significantly decreased proliferation. Northern blot and reverse transcription/polymerase chain reaction of a panel of various tissues have shown that HES5 is transcribed as a 5.4-kb mRNA that is ubiquitously expressed in diverse fetal and adult tissues. Articular cartilage from HES5(-/-) and wild-type mice has been analyzed by using various histological stains. No differences have been detected between the wild-type and HES5(-/-) mice. Our data thus indicate that the human HES5 gene is coupled to the Notch receptor family, that expression of Notch markers (including HES5) decreases during cartilage differentiation, and that the blockage of Notch signaling is associated with significantly decreased cell proliferation.
|
|
| 3. |
- Asp, Julia, 1973, et al.
(författare)
-
Changes in p14(ARF) do not play a primary role in human chondrosarcoma tissues.
- 2001
-
Ingår i: International journal of cancer. Journal international du cancer. - 0020-7136. ; 93:5, s. 703-5
-
Tidskriftsartikel (refereegranskat)abstract
- The locus encoding the tumor suppressor p16 has been found to code for a second, different protein. This protein, p14(ARF), has been shown to protect p53 from degradation. Like p16, its gene is often altered in different cancers. In this study, the first unique exon, exon 1 beta, of p14(ARF), has been studied in 22 chondrosarcoma tissues using polymerase chain reaction, DNA sequencing and methylation-specific polymerase chain reaction. One chondrosarcoma was found to have exon 1 beta homozygously deleted, but neither mutations nor methylations were found in any of the chondrosarcomas. This indicates that genetic changes of p14(ARF) are a rare event in chondrosarcoma.
|
|
| 4. |
- Asp, Julia, 1973, et al.
(författare)
-
Evaluation of p16 and Id1 status and endogenous reference genes in human chondrosarcoma by real-time PCR.
- 2005
-
Ingår i: International journal of oncology. - 1019-6439. ; 27:6, s. 1577-82
-
Tidskriftsartikel (refereegranskat)abstract
- Both the tumour suppressor, p16, and the helix-loop-helix transcription factor, Id1, have been assigned roles in tumour growth in general and appear to be involved in chondrosarcoma. Id1 has further been found to repress the expression of p16. Therefore, the mRNA expression of these two genes was studied by real-time PCR in a search for prognostic markers in human chondrosarcoma. To get reliable quantitative data, however, the choice of endogenous reference gene for use in the assay is important. Therefore, eleven different endogenous reference genes were evaluated in chondrosarcoma cells and articular chondrocytes. 18S rRNA appeared to be the best choice to use as endogenous reference gene, since it was suitable for both kinds of cells. Several of the other reference genes tested showed variation between individuals or between normal chondrocytes and chondrosarcoma cells. This demonstrates the importance of using a correct endogenous reference gene to get reliable results from quantitative measurements. Both p16 and Id1 showed varied gene expression patterns among the samples and none of these genes could be significantly correlated to prognosis.
|
|
| 5. |
|
|
| 6. |
- Vukusic, Kristina, 1979, et al.
(författare)
-
High Density Sphere Culture of Adult Cardiac Cells Increases the Levels of Cardiac and Progenitor Markers and Shows Signs of Vasculogenesis
- 2013
-
Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
-
Tidskriftsartikel (refereegranskat)abstract
- 3D environment and high cell density play an important role in restoring and supporting the phenotypes of cells represented in cardiac tissues.. e aim of this study was therefore to investigate the suitability of high density sphere (HDS) cultures for studies of cardiomyocyte-, endothelial-, and stem-cell biology. Primary adult cardiac cells from nine human biopsies were cultured using different media for up to 9 weeks.. e possibilities to favor a certain cell phenotype and induce production of extra cellular matrix (ECM) were studied by histology, immunohistochemistry, and uantitative real-time PCR. Defined media gave significant increase in both cardiac-and progenitor-specific markers and also an intraluminal position of endothelial cells over time. Cardiac media showed indication of differentiation and maturity of HDS considering the ECM production and activities within NOTCH regulation but no additional cardiac differentiation. Endothelial media gave no positive effects on endothelial phenotype but increased proliferation without fibroblast overgrowth. In addition, indications for early vasculogenesis were found. It was also possible to affect the Wnt signaling in HDS by addition of a glycogen synthase kinase 3 (GSK3) inhibitor. In conclusion, these findings show the suitability of HDS as in vitro model for studies of cardiomyocyte-, endothelial-, and stem-cell biology.
|
|
