Abstract
The localization of osteopontin (OP) was examined in Meckel's cartilage cells that bipotentially expressed cartilage and bone phenotypes during cellular transformation in vitro. Cultured cells were analyzed by in situ hybridization, immunostaining followed by light and electron microscopy, electron microscopy, and electron probe microanalysis. The combination of ultrastructural analysis and immunoperoxidase staining indicated that OP- synthesizing cells were cells that were autonomously undergoing a change from chondrocytes to bone-forming cells at the top of nodules. Double immunofluorescence staining of 2-week-old cultures revealed that OP was first synthesized by chondrocytic cells at the top of nodules. After further time in culture, the distribution of OP expanded from the central toward the peripheral regions of the nodules. Electron probe microanalysis revealed that the localization of OP was associated with matrices of calcified cartilage and osteoid nodules that contained calcium and phosphorus. Immunoperoxidase electron microscopy revealed that, in addition to the intracellular immunoreactivity in chondrocytes and small round cells that were undergoing transformation, matrix foci of calcospherites and matrix vesicles, in particular, included growing crystals that were immunopositive for OP. An intense signal due to mRNA for OP in 3-week-old cultures was detected in nodule-forming round cells, while fibroblastic cells, spreading in a monolayer over the periphery of nodules, were only weakly labeled. These findings indicate that OP might be expressed sequentially by chondrocytes and by cells that are transdifferentiating further and exhibit an osteocytic phenotype, and moreover, that expression of OP is closely associated with calcifying foci in the extracellular matrix.
| Original language | English |
|---|---|
| Pages (from-to) | 457-466 |
| Number of pages | 10 |
| Journal | Histochemistry and Cell Biology |
| Volume | 110 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 1998 |
Fingerprint
ASJC Scopus subject areas
- Cell Biology
- Instrumentation
Cite this
Expression of osteopontin in Meckel's cartilage cells during phenotypic transdifferentiation in vitro, as detected by in situ hybridization and immunocytochemical analysis. / Ishizeki, Kiyoto; Nomura, Shintaro; Takigawa, Masaharu; Shioji, Hiroya; Nawa, Tokio.
In: Histochemistry and Cell Biology, Vol. 110, No. 5, 1998, p. 457-466.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Expression of osteopontin in Meckel's cartilage cells during phenotypic transdifferentiation in vitro, as detected by in situ hybridization and immunocytochemical analysis
AU - Ishizeki, Kiyoto
AU - Nomura, Shintaro
AU - Takigawa, Masaharu
AU - Shioji, Hiroya
AU - Nawa, Tokio
PY - 1998
Y1 - 1998
N2 - The localization of osteopontin (OP) was examined in Meckel's cartilage cells that bipotentially expressed cartilage and bone phenotypes during cellular transformation in vitro. Cultured cells were analyzed by in situ hybridization, immunostaining followed by light and electron microscopy, electron microscopy, and electron probe microanalysis. The combination of ultrastructural analysis and immunoperoxidase staining indicated that OP- synthesizing cells were cells that were autonomously undergoing a change from chondrocytes to bone-forming cells at the top of nodules. Double immunofluorescence staining of 2-week-old cultures revealed that OP was first synthesized by chondrocytic cells at the top of nodules. After further time in culture, the distribution of OP expanded from the central toward the peripheral regions of the nodules. Electron probe microanalysis revealed that the localization of OP was associated with matrices of calcified cartilage and osteoid nodules that contained calcium and phosphorus. Immunoperoxidase electron microscopy revealed that, in addition to the intracellular immunoreactivity in chondrocytes and small round cells that were undergoing transformation, matrix foci of calcospherites and matrix vesicles, in particular, included growing crystals that were immunopositive for OP. An intense signal due to mRNA for OP in 3-week-old cultures was detected in nodule-forming round cells, while fibroblastic cells, spreading in a monolayer over the periphery of nodules, were only weakly labeled. These findings indicate that OP might be expressed sequentially by chondrocytes and by cells that are transdifferentiating further and exhibit an osteocytic phenotype, and moreover, that expression of OP is closely associated with calcifying foci in the extracellular matrix.
AB - The localization of osteopontin (OP) was examined in Meckel's cartilage cells that bipotentially expressed cartilage and bone phenotypes during cellular transformation in vitro. Cultured cells were analyzed by in situ hybridization, immunostaining followed by light and electron microscopy, electron microscopy, and electron probe microanalysis. The combination of ultrastructural analysis and immunoperoxidase staining indicated that OP- synthesizing cells were cells that were autonomously undergoing a change from chondrocytes to bone-forming cells at the top of nodules. Double immunofluorescence staining of 2-week-old cultures revealed that OP was first synthesized by chondrocytic cells at the top of nodules. After further time in culture, the distribution of OP expanded from the central toward the peripheral regions of the nodules. Electron probe microanalysis revealed that the localization of OP was associated with matrices of calcified cartilage and osteoid nodules that contained calcium and phosphorus. Immunoperoxidase electron microscopy revealed that, in addition to the intracellular immunoreactivity in chondrocytes and small round cells that were undergoing transformation, matrix foci of calcospherites and matrix vesicles, in particular, included growing crystals that were immunopositive for OP. An intense signal due to mRNA for OP in 3-week-old cultures was detected in nodule-forming round cells, while fibroblastic cells, spreading in a monolayer over the periphery of nodules, were only weakly labeled. These findings indicate that OP might be expressed sequentially by chondrocytes and by cells that are transdifferentiating further and exhibit an osteocytic phenotype, and moreover, that expression of OP is closely associated with calcifying foci in the extracellular matrix.
UR - http://www.scopus.com/inward/record.url?scp=0031754606&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031754606&partnerID=8YFLogxK
U2 - 10.1007/s004180050307
DO - 10.1007/s004180050307
M3 - Article
C2 - 9826125
AN - SCOPUS:0031754606
VL - 110
SP - 457
EP - 466
JO - Histochemistry and Cell Biology
JF - Histochemistry and Cell Biology
SN - 0948-6143
IS - 5
ER -