TY - JOUR
T1 - Treatment of resting zone chondrocytes with bone morphogenetic protein- 2 induces maturation into a phenotype characteristic of growth zone chondrocytes by downregulating responsiveness to 24,25(OH)2D3 and upregulating responsiveness to 1,25-(OH)2D3
AU - Schwartz, Zvi
AU - Sylvia, Victor L.
AU - Liu, Yuhong
AU - Dean, David D.
AU - Boyan, Barbara D.
N1 - Funding Information:
The authors acknowledge the contributions of Yuhong Liu, Zhi Chang, Roland Campos, and Jayme Solis to the technical aspects of this work, and to Sandra Messier for assistance with manuscript preparation. The studies were supported through grants from the National Institute of Dental Research (DE-08603 and DE-05937), the Center for the Enhancement of the Biology/Biomaterials Interface, and OsteoBiologics, Inc., San Antonio, TX.
PY - 1998
Y1 - 1998
N2 - To determine if bone morphogenetic protein-2 (BMP-2) can induce the endochondral maturation of resting zone (RC) chondrocytes, confluent fourth- passage cultures of these cells were pretreated for 24, 36, 48, 72, or 120 h with recombinant human BMP-2. At the end of pretreatment, the media were replaced with new media containing 10-10-10-8 M 1,25-(OH)2D3 or 10- 9-10-7 M 24,25-(OH2)D3 and the cells incubated for an additional 24 h. This second treatment was chosen, because prior studies had shown that the more mature growth zone (GC) chondrocytes and RC cells respond to 1,25- (OH)2D3 and 24,25-(OH)2D3 in distinctly different ways with respect to the parameters examined. The effect of BMP-2 pretreatment on cell maturation was assessed by measuring alkaline phosphatase specific activity (ALPase). In addition, changes in matrix protein production were assessed by measuring collagen synthesis, as well as [35S]-sulfate incorporation into proteoglycans. When RC cells were pretreated for 72 or 120 h with BMP-2, treatment with 1,25-(OH)2D3 caused a dose-dependent increase in ALPase specific activity and collagen synthesis, with no effect on proteoglycan sulfation. RC cells pretreated with 1,25(OH)2D3 responded like RC cells that had not received any pretreatment. RC cells normally respond to 24,25- (OH)2D3; however, RC cultures pretreated for 72 or 120 h with BMP-2 lost their responsiveness to 24,25-(OH)2D3. These results indicate that BMP-2 directly regulates the differentiation and maturation of RC chondrocytes into GC chondrocytes. These observations support the hypothesis that BMP-2 plays a significant role in regulating chondrocyte maturation during endochondral ossification.
AB - To determine if bone morphogenetic protein-2 (BMP-2) can induce the endochondral maturation of resting zone (RC) chondrocytes, confluent fourth- passage cultures of these cells were pretreated for 24, 36, 48, 72, or 120 h with recombinant human BMP-2. At the end of pretreatment, the media were replaced with new media containing 10-10-10-8 M 1,25-(OH)2D3 or 10- 9-10-7 M 24,25-(OH2)D3 and the cells incubated for an additional 24 h. This second treatment was chosen, because prior studies had shown that the more mature growth zone (GC) chondrocytes and RC cells respond to 1,25- (OH)2D3 and 24,25-(OH)2D3 in distinctly different ways with respect to the parameters examined. The effect of BMP-2 pretreatment on cell maturation was assessed by measuring alkaline phosphatase specific activity (ALPase). In addition, changes in matrix protein production were assessed by measuring collagen synthesis, as well as [35S]-sulfate incorporation into proteoglycans. When RC cells were pretreated for 72 or 120 h with BMP-2, treatment with 1,25-(OH)2D3 caused a dose-dependent increase in ALPase specific activity and collagen synthesis, with no effect on proteoglycan sulfation. RC cells pretreated with 1,25(OH)2D3 responded like RC cells that had not received any pretreatment. RC cells normally respond to 24,25- (OH)2D3; however, RC cultures pretreated for 72 or 120 h with BMP-2 lost their responsiveness to 24,25-(OH)2D3. These results indicate that BMP-2 directly regulates the differentiation and maturation of RC chondrocytes into GC chondrocytes. These observations support the hypothesis that BMP-2 plays a significant role in regulating chondrocyte maturation during endochondral ossification.
KW - BMP- 2
KW - Chondrocytes
KW - Differentiation
KW - Growth plate cartilage
KW - Maturation
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U2 - 10.1385/ENDO:9:3:273
DO - 10.1385/ENDO:9:3:273
M3 - Article
C2 - 10221593
AN - SCOPUS:0032464680
SN - 1355-008X
VL - 9
SP - 273
EP - 280
JO - Endocrine
JF - Endocrine
IS - 3
ER -