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Articular Chondroprogenitor Cells Maintain Chondrogenic Potential but Fail to Form a Functional Matrix When Implanted Into Muscles of SCID Mice.

Marcus P, De Bari C, Dell'Accio F, Archer CW - Cartilage (2014)

Bottom Line: After injection with clonal and enriched populations of chondroprogenitors, no distinct pellet was detected, but diffuse cartilage nodules were found with regions of safranin O staining and Sox9.The bovine articular cartilage progenitor cells were able to survive in vivo postimplantation, but failed to create a robust cartilage pellet, despite expressing sox9 and type II collagen.This suggests the cells require further signals for chondrogenic differentiation.

View Article: PubMed Central - PubMed

Affiliation: Cardiff School of Bioscience, Cardiff University, Cardiff, UK.

ABSTRACT

Objective: Articular cartilage is a complex tissue comprising phenotypically distinct zones. Research has identified the presence of a progenitor cell population in the surface zone of immature articular cartilage. The aim of the present study was to determine the in vivo plasticity of articular cartilage progenitor.

Design: Chondropogenitor cells were isolated from bovine metacarpalphalangeal joints by differential adhesion to fibronectin. Cells were labeled with PKH26 and injected into the thigh muscle of severe-combined immunodeficient (SCID) mice. After 2 weeks, the muscles were dissected and cryosectioned. Sections were stained with safranin O and labeled for sox9 and collagen type II. Polymerase chain reaction analysis was carried out to determine plasticity for a number of tissue-specific markers. Full-depth chondrocytes acted as a control.

Results: Fluorescent PKH26 labeled cells were detected after 2 weeks in all samples analyzed. A cartilage pellet was present after injection of freshly isolated chondrocytes. After injection with clonal and enriched populations of chondroprogenitors, no distinct pellet was detected, but diffuse cartilage nodules were found with regions of safranin O staining and Sox9. Low levels of collagen type II were also detected. Polymerase chain reaction analysis identified the presence of the endothelial cell marker PECAM-1 in one clonal cell line, demonstrating phenotypic plasticity into the phenotype of the surrounding host tissues.

Conclusions: The bovine articular cartilage progenitor cells were able to survive in vivo postimplantation, but failed to create a robust cartilage pellet, despite expressing sox9 and type II collagen. This suggests the cells require further signals for chondrogenic differentiation.

No MeSH data available.


Related in: MedlinePlus

Immunolabeling of implanted chondrocytes with Sox9 antibody. Immunolabeled muscle samples from mice injected with bovine full depth (A, B), clonal (C, D), and enriched (E, F) after 2 weeks. Extensive Sox9 labeling was seen in the full-depth pellet as indicated by the arrows (A). In both the clonal and enriched chondroprogenitor populations isolated cells labeled positively for Sox9. These areas corresponded to regions with PKH26 positive cells (C and E). Corresponding bright field images are shown (B, D, and F). Human unlabeled full-depth cells were used as a negative control (G, H). Positive Sox9 labeling could be seen in these samples even in the absence of PKH26. Cells were labeled with PKH26 (red), Sox9 (green), and nuclear stain (blue). Phase contrast images were taken of corresponding regions. Scale = 65 µm.
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fig3-1947603514541274: Immunolabeling of implanted chondrocytes with Sox9 antibody. Immunolabeled muscle samples from mice injected with bovine full depth (A, B), clonal (C, D), and enriched (E, F) after 2 weeks. Extensive Sox9 labeling was seen in the full-depth pellet as indicated by the arrows (A). In both the clonal and enriched chondroprogenitor populations isolated cells labeled positively for Sox9. These areas corresponded to regions with PKH26 positive cells (C and E). Corresponding bright field images are shown (B, D, and F). Human unlabeled full-depth cells were used as a negative control (G, H). Positive Sox9 labeling could be seen in these samples even in the absence of PKH26. Cells were labeled with PKH26 (red), Sox9 (green), and nuclear stain (blue). Phase contrast images were taken of corresponding regions. Scale = 65 µm.

Mentions: Sections were then labeled for the transcription factor Sox9 and collagen type II. Full-depth chondrocytes were found to express high levels of Sox9, with intense labeling seen within the pellet (Fig. 3A). This pellet also labeled positively for type II collagen (Fig. 4A). The human full-depth chondrocytes were also positive for both Sox9 and type II collagen (Figs. 3G and 4D). After injection, with bovine clonal and enriched populations, no type II collagen could be detected by imunocytochemistry in any of the sections analyzed (Fig. 4B, C). Despite this absence, Sox9 was detected in some of the PKH26 positive cells, whereas other cells appeared negative (Fig. 3C, E).


Articular Chondroprogenitor Cells Maintain Chondrogenic Potential but Fail to Form a Functional Matrix When Implanted Into Muscles of SCID Mice.

Marcus P, De Bari C, Dell'Accio F, Archer CW - Cartilage (2014)

Immunolabeling of implanted chondrocytes with Sox9 antibody. Immunolabeled muscle samples from mice injected with bovine full depth (A, B), clonal (C, D), and enriched (E, F) after 2 weeks. Extensive Sox9 labeling was seen in the full-depth pellet as indicated by the arrows (A). In both the clonal and enriched chondroprogenitor populations isolated cells labeled positively for Sox9. These areas corresponded to regions with PKH26 positive cells (C and E). Corresponding bright field images are shown (B, D, and F). Human unlabeled full-depth cells were used as a negative control (G, H). Positive Sox9 labeling could be seen in these samples even in the absence of PKH26. Cells were labeled with PKH26 (red), Sox9 (green), and nuclear stain (blue). Phase contrast images were taken of corresponding regions. Scale = 65 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4335766&req=5

fig3-1947603514541274: Immunolabeling of implanted chondrocytes with Sox9 antibody. Immunolabeled muscle samples from mice injected with bovine full depth (A, B), clonal (C, D), and enriched (E, F) after 2 weeks. Extensive Sox9 labeling was seen in the full-depth pellet as indicated by the arrows (A). In both the clonal and enriched chondroprogenitor populations isolated cells labeled positively for Sox9. These areas corresponded to regions with PKH26 positive cells (C and E). Corresponding bright field images are shown (B, D, and F). Human unlabeled full-depth cells were used as a negative control (G, H). Positive Sox9 labeling could be seen in these samples even in the absence of PKH26. Cells were labeled with PKH26 (red), Sox9 (green), and nuclear stain (blue). Phase contrast images were taken of corresponding regions. Scale = 65 µm.
Mentions: Sections were then labeled for the transcription factor Sox9 and collagen type II. Full-depth chondrocytes were found to express high levels of Sox9, with intense labeling seen within the pellet (Fig. 3A). This pellet also labeled positively for type II collagen (Fig. 4A). The human full-depth chondrocytes were also positive for both Sox9 and type II collagen (Figs. 3G and 4D). After injection, with bovine clonal and enriched populations, no type II collagen could be detected by imunocytochemistry in any of the sections analyzed (Fig. 4B, C). Despite this absence, Sox9 was detected in some of the PKH26 positive cells, whereas other cells appeared negative (Fig. 3C, E).

Bottom Line: After injection with clonal and enriched populations of chondroprogenitors, no distinct pellet was detected, but diffuse cartilage nodules were found with regions of safranin O staining and Sox9.The bovine articular cartilage progenitor cells were able to survive in vivo postimplantation, but failed to create a robust cartilage pellet, despite expressing sox9 and type II collagen.This suggests the cells require further signals for chondrogenic differentiation.

View Article: PubMed Central - PubMed

Affiliation: Cardiff School of Bioscience, Cardiff University, Cardiff, UK.

ABSTRACT

Objective: Articular cartilage is a complex tissue comprising phenotypically distinct zones. Research has identified the presence of a progenitor cell population in the surface zone of immature articular cartilage. The aim of the present study was to determine the in vivo plasticity of articular cartilage progenitor.

Design: Chondropogenitor cells were isolated from bovine metacarpalphalangeal joints by differential adhesion to fibronectin. Cells were labeled with PKH26 and injected into the thigh muscle of severe-combined immunodeficient (SCID) mice. After 2 weeks, the muscles were dissected and cryosectioned. Sections were stained with safranin O and labeled for sox9 and collagen type II. Polymerase chain reaction analysis was carried out to determine plasticity for a number of tissue-specific markers. Full-depth chondrocytes acted as a control.

Results: Fluorescent PKH26 labeled cells were detected after 2 weeks in all samples analyzed. A cartilage pellet was present after injection of freshly isolated chondrocytes. After injection with clonal and enriched populations of chondroprogenitors, no distinct pellet was detected, but diffuse cartilage nodules were found with regions of safranin O staining and Sox9. Low levels of collagen type II were also detected. Polymerase chain reaction analysis identified the presence of the endothelial cell marker PECAM-1 in one clonal cell line, demonstrating phenotypic plasticity into the phenotype of the surrounding host tissues.

Conclusions: The bovine articular cartilage progenitor cells were able to survive in vivo postimplantation, but failed to create a robust cartilage pellet, despite expressing sox9 and type II collagen. This suggests the cells require further signals for chondrogenic differentiation.

No MeSH data available.


Related in: MedlinePlus