Faculty Opinions recommendation of Hypertrophic chondrocytes can become osteoblasts and osteocytes in endochondral bone formation.

Abstract The hypoxic growth plate cartilage requires hypoxia-inducible factor (HIF)-mediated pathways to maintain chondrocyte survival and differentiation. HIF proteins are tightly regulated by prolyl hydroxylase domain-containing protein 2 (Phd2)-mediated proteosomal degradation. We conditionally disrupted the Phd2 gene in chondrocytes by crossing Phd2 floxed mice with type 2 collagen-α1-Cre transgenic mice and found massive increases (>50%) in the trabecular bone mass of long bones and lumbar vertebra of the Phd2 conditional knockout (cKO) mice caused by significant increases in trabecular number and thickness and reductions in trabecular separation. Cortical thickness and tissue mineral density at the femoral middiaphysis of the cKO mice were also significantly increased. Dynamic histomorphometric analyses revealed increased longitudinal length and osteoid surface per bone surface in the primary spongiosa of the cKO mice, suggesting elevated conversion rate from hypertrophic chondrocytes to mineralized bone matrix as well as increased bone formation in the primary spongiosa. In the secondary spongiosa, bone formation measured by mineralizing surface per bone surface and mineral apposition rate were not changed, but resorption was slightly reduced. Increases in the mRNA levels of SRY (sex determining region Y)-box 9, osterix (Osx), type 2 collagen, aggrecan, alkaline phosphatase, bone sialoprotein, vascular endothelial growth factor, erythropoietin, and glycolytic enzymes in the growth plate of cKO mice were detected by quantitative RT-PCR. Immunohistochemistry revealed an increased HIF-1α protein level in the hypertrophic chondrocytes of cKO mice. Infection of chondrocytes isolated from Phd2 floxed mice with adenoviral Cre resulted in similar gene expression patterns as observed in the cKO growth plate chondrocytes. Our findings indicate that Phd2 suppresses endochondral bone formation, in part, via HIF-dependent mechanisms in mice.

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Fetal Jaw Movement Affects Condylar Cartilage Development

Journal of Dental Research ◽

10.1177/154405910508400514 ◽

2005 ◽

Vol 84 (5) ◽

pp. 474-479 ◽

Cited By ~ 30

Author(s):

H. Habib ◽

T. Hatta ◽

J. Udagawa ◽

L. Zhang ◽

Y. Yoshimura ◽

...

Keyword(s):

Bone Formation ◽

Mandibular Condyle ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Condylar Cartilage ◽

Mechanical Factor ◽

Endochondral Bone ◽

Jaw Movement ◽

Cartilage Development ◽

Number Of Cells

Using a mouse exo utero system to examine the effects of fetal jaw movement on the development of condylar cartilage, we assessed the effects of restraint of the animals’ mouths from opening, by suture, at embryonic day (E)15.5. We hypothesized that pre-natal jaw movement is an important mechanical factor in endochondral bone formation of the mandibular condyle. Condylar cartilage was reduced in size, and the bone-cartilage margin was ill-defined in the sutured group at E18.5. Volume, total number of cells, and number of 5-bromo-2′-deoxyuridine-positive cells in the mesenchymal zone were lower in the sutured group than in the non-sutured group at E16.5 and E18.5. Hypertrophic chondrocytes were larger, whereas fewer apoptotic chondrocytes and osteoclasts were observed in the hypertrophic zone in the sutured group at E18.5. Analysis of our data revealed that restricted fetal TMJ movement influences the process of endochondral bone formation of condylar cartilage.

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FGFR1 signaling in hypertrophic chondrocytes is attenuated by the Ras-GAP neurofibromin during endochondral bone formation

Human Molecular Genetics ◽

10.1093/hmg/ddv019 ◽

2015 ◽

Vol 24 (9) ◽

pp. 2552-2564 ◽

Cited By ~ 16

Author(s):

Matthew R. Karolak ◽

Xiangli Yang ◽

Florent Elefteriou

Keyword(s):

Bone Formation ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Endochondral Bone

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Hypertrophic chondrocytes can become osteoblasts and osteocytes in endochondral bone formation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1302703111 ◽

2014 ◽

Vol 111 (33) ◽

pp. 12097-12102 ◽

Cited By ~ 341

Author(s):

L. Yang ◽

K. Y. Tsang ◽

H. C. Tang ◽

D. Chan ◽

K. S. E. Cheah

Keyword(s):

Bone Formation ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Endochondral Bone

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Galectin-3 Is a Downstream Regulator of Matrix Metalloproteinase-9 Function during Endochondral Bone Formation

Molecular Biology of the Cell ◽

10.1091/mbc.e04-12-1119 ◽

2005 ◽

Vol 16 (6) ◽

pp. 3028-3039 ◽

Cited By ~ 63

Author(s):

Nathalie Ortega ◽

Danielle J. Behonick ◽

Céline Colnot ◽

Douglas N.W. Cooper ◽

Zena Werb

Keyword(s):

Bone Formation ◽

Matrix Metalloproteinase ◽

Growth Plate ◽

Matrix Metalloproteinase 9 ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Endochondral Bone ◽

Chondrocyte Death ◽

Galectin 3 ◽

Metalloproteinase 9

Endochondral bone formation is characterized by the progressive replacement of a cartilage anlagen by bone at the growth plate with a tight balance between the rates of chondrocyte proliferation, differentiation, and cell death. Deficiency of matrix metalloproteinase-9 (MMP-9) leads to an accumulation of late hypertrophic chondrocytes. We found that galectin-3, an in vitro substrate of MMP-9, accumulates in the late hypertrophic chondrocytes and their surrounding extracellular matrix in the expanded hypertrophic cartilage zone. Treatment of wild-type embryonic metatarsals in culture with full-length galectin-3, but not galectin-3 cleaved by MMP-9, mimicked the embryonic phenotype of Mmp-9 null mice, with an increased hypertrophic zone and decreased osteoclast recruitment. These results indicate that extracellular galectin-3 could be an endogenous substrate of MMP-9 that acts downstream to regulate hypertrophic chondrocyte death and osteoclast recruitment during endochondral bone formation. Thus, the disruption of growth plate homeostasis in Mmp-9 null mice links galectin-3 and MMP-9 in the regulation of the clearance of late chondrocytes through regulation of their terminal differentiation.

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Association of an extracellular protein (chondrocalcin) with the calcification of cartilage in endochondral bone formation.

The Journal of Cell Biology ◽

10.1083/jcb.98.1.54 ◽

1984 ◽

Vol 98 (1) ◽

pp. 54-65 ◽

Cited By ~ 100

Author(s):

A R Poole ◽

I Pidoux ◽

A Reiner ◽

H Choi ◽

L C Rosenberg

Keyword(s):

Extracellular Matrix ◽

Bone Formation ◽

Growth Plate ◽

Calcium Binding ◽

Calcium Binding Protein ◽

Cartilage Matrix ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Endochondral Bone ◽

Nucleation Sites

We examined bovine fetal epiphyseal and growth plate cartilages by immunofluorescence microscopy and immunoelectron microscopy using monospecific antibodies to a newly discovered cartilage-matrix calcium-binding protein that we now call chondrocalcin. Chondrocalcin was evenly distributed at relatively low concentration in resting fetal epiphyseal cartilage. In growth plate cartilage, it was absent from the extracellular matrix in the zone of proliferating chondrocytes but was present in intracellular vacuoles in proliferating, maturing and upper hypertrophic chondrocytes. The protein then disappeared from the lower hypertrophic chondrocytes and appeared in the adjoining extracellular matrix, where it was selectively concentrated in the longitudinal septa in precisely the same location where amorphous mineral was deposited in large amounts as demonstrated by von Kossa staining and electron microscopy. Mineral then spread out from these "nucleation sites" to occupy much of the surrounding matrix. Matrix vesicles were identified in this calcifying matrix but they bore no observable morphological relationship to these major sites of calcification where chondrocalcin was concentrated. Since chondrocalcin is a calcium-binding protein and has a strong affinity for hydroxyapatite, these observations suggest that chondrocalcin may play a fundamental role in the creation of nucleation sites for the calcification of cartilage matrix in endochondral bone formation.

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Ovotransferrin and ovotransferrin receptor expression during chondrogenesis and endochondral bone formation in developing chick embryo

The Journal of Cell Biology ◽

10.1083/jcb.124.4.579 ◽

1994 ◽

Vol 124 (4) ◽

pp. 579-588 ◽

Cited By ~ 41

Author(s):

C Gentili ◽

R Doliana ◽

P Bet ◽

G Campanile ◽

A Colombatti ◽

...

Keyword(s):

Chick Embryo ◽

Bone Formation ◽

Blot Analysis ◽

Receptor Expression ◽

Hypertrophic Chondrocytes ◽

Endochondral Bone Formation ◽

Metabolic Labeling ◽

Matrix Assembly ◽

Endochondral Bone ◽

Low Level

Ovotransferrin expression during chick embryo tibia development has been investigated in vivo by immunocytochemistry and in situ hybridization. Ovotransferrin was first observed in the 7 day cartilaginous rudiment. At later stages, the factor was localized in the articular zone of the bone epiphysis and in the bone diaphysis where it was concentrated in hypertrophic cartilage, in zones of cartilage erosion and in the osteoid at the chondro-bone junction. When the localization of the ovotransferrin receptors was investigated, it was observed that chondrocytes at all stages of differentiation express a low level of the oviduct (tissue) specific receptor. Interestingly, high levels of the receptor were detectable in the 13-d old tibia in the diaphysis collar of stacked-osteoprogenitor cells and in the layer of derived osteoblasts. High levels of oviduct receptor were also observed in the primordia of the menisci. Metabolic labeling of proteins secreted by cultured chondrocytes and osteoblasts and Northern blot analysis of RNA extracted from the same cells confirmed and completed the above information. Ovotransferrin was expressed by in vitro differentiating chondrocytes in the early phase of the culture and, at least when culture conditions allowed extracellular matrix assembly, also by hypertrophic chondrocytes and derived osteoblast-like cells. Osteoblasts directly obtained from bone chips produced ovotransferrin only at the time of culture mineralization. By Western blot analysis, oviduct receptor proteins were detected at a very low level in extract from differentiating and hypertrophic chondrocytes and at a higher level in extract from hypertrophic chondrocytes undergoing differentiation to osteoblast-like cells and from mineralizing osteoblasts. Based on these results, the existence of autocrine and paracrine loops involving ovotransferrin and its receptor during chondrogenesis and endochondral bone formation is discussed.

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Faculty Opinions recommendation of Intraflagellar transport is essential for endochondral bone formation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1059698.511609 ◽

2007 ◽

Author(s):

Peter Scambler

Keyword(s):

Bone Formation ◽

Intraflagellar Transport ◽

Endochondral Bone Formation ◽

Endochondral Bone

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The culture microenvironment of juvenile idiopathic arthritis synovial fibroblasts is favorable for endochondral bone formation through BMP4 and repressed by chondrocytes

Pediatric Rheumatology ◽

10.1186/s12969-021-00556-8 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Megan M. Simonds ◽

Amanda R. Schlefman ◽

Suzanne M. McCahan ◽

Kathleen E. Sullivan ◽

Carlos D. Rose ◽

...

Keyword(s):

Juvenile Idiopathic Arthritis ◽

Bone Formation ◽

Synovial Fibroblasts ◽

Conditioned Media ◽

Endochondral Bone Formation ◽

Endochondral Bone ◽

Member Gene ◽

Bmp Antagonist ◽

Fibroblast Like Synoviocytes ◽

Tgfβ Superfamily

Abstract Background We examined influences of conditioned media from chondrocytes (Ch) on juvenile idiopathic arthritis synovial fibroblasts (JFLS) and potential for JFLS to undergo endochondral bone formation (EBF). Methods Primary cells from three control fibroblast-like synoviocytes (CFLS) and three JFLS were cultured in Ch-conditioned media and compared with untreated fibroblast-like synoviocytes (FLS). RNA was analyzed by ClariomS microarray. FLS cells cultured in conditioned media were exposed to either TGFBR1 inhibitor LY3200882 or exogenous BMP4 and compared with FLS cultured in conditioned media from Ch (JFLS-Ch). Media supernatants were analyzed by ELISA. Results In culture, JFLS downregulate BMP2 and its receptor BMPR1a while upregulating BMP antagonists (NOG and CHRD) and express genes (MMP9, PCNA, MMP12) and proteins (COL2, COLX, COMP) associated with chondrocytes. Important TGFβ superfamily member gene expression (TGFBI, MMP9, COL1A1, SOX6, and MMP2) is downregulated when JFLS are cultured in Ch-conditioned media. COL2, COLX and COMP protein expression decreases in JFLS-Ch. BMP antagonist protein (NOG, CHRD, GREM, and FST) secretion is significantly increased in JFLS-Ch. Protein phosphorylation increases in JFLS-Ch exposed to exogenous BMP4, and chondrocyte-like phenotype is restored in BMP4 presence, evidenced by increased secretion of COL2 and COLX. Inhibition of TGFBR1 in JFLS-Ch results in overexpression of COL2. Conclusions JFLS are chondrocyte-like, and Ch-conditioned media can abrogate this phenotype. The addition of exogenous BMP4 causes JFLS-Ch to restore this chondrocyte-like phenotype, suggesting that JFLS create a microenvironment favorable for endochondral bone formation, thereby contributing to joint growth disturbances in juvenile idiopathic arthritis.

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