Cross‐talk between EGFR and BMP Signals Regulates Chondrocyte Maturation during Endochondral Ossification

During skeletogenesis, cartilage develops to either permanent cartilage that persists through life or transient cartilage that is eventually replaced by bone. However, the mechanism by which cartilage phenotype is specified remains unclarified. Core binding factor α1 (Cbfa1) is an essential transcription factor for osteoblast differentiation and bone formation and has the ability to stimulate chondrocyte maturation in vitro. To understand the roles of Cbfa1 in chondrocytes during skeletal development, we generated transgenic mice that overexpress Cbfa1 or a dominant negative (DN)-Cbfa1 in chondrocytes under the control of a type II collagen promoter/enhancer. Both types of transgenic mice displayed dwarfism and skeletal malformations, which, however, resulted from opposite cellular phenotypes. Cbfa1 overexpression caused acceleration of endochondral ossification due to precocious chondrocyte maturation, whereas overexpression of DN-Cbfa1 suppressed maturation and delayed endochondral ossification. In addition, Cbfa1 transgenic mice failed to form most of their joints and permanent cartilage entered the endochondral pathway, whereas most chondrocytes in DN-Cbfa1 transgenic mice retained a marker for permanent cartilage. These data show that temporally and spatially regulated expression of Cbfa1 in chondrocytes is required for skeletogenesis, including formation of joints, permanent cartilages, and endochondral bones.

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Recapitulation of physiological spatiotemporal signals promotes in vitro formation of phenotypically stable human articular cartilage

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1611771114 ◽

2017 ◽

Vol 114 (10) ◽

pp. 2556-2561 ◽

Cited By ~ 19

Author(s):

Johnathan J. Ng ◽

Yiyong Wei ◽

Bin Zhou ◽

Jonathan Bernhard ◽

Samuel Robinson ◽

...

Keyword(s):

Articular Cartilage ◽

Endochondral Ossification ◽

Human Articular Cartilage ◽

Control Groups ◽

Human Cartilage ◽

Chondrocyte Maturation ◽

Self Assembling ◽

Spatiotemporal Regulation

Standard isotropic culture fails to recapitulate the spatiotemporal gradients present during native development. Cartilage grown from human mesenchymal stem cells (hMSCs) is poorly organized and unstable in vivo. We report that human cartilage with physiologic organization and in vivo stability can be grown in vitro from self-assembling hMSCs by implementing spatiotemporal regulation during induction. Self-assembling hMSCs formed cartilage discs in Transwell inserts following isotropic chondrogenic induction with transforming growth factor β to set up a dual-compartment culture. Following a switch in the basal compartment to a hypertrophic regimen with thyroxine, the cartilage discs underwent progressive deep-zone hypertrophy and mineralization. Concurrent chondrogenic induction in the apical compartment enabled the maintenance of functional and hyaline cartilage. Cartilage homeostasis, chondrocyte maturation, and terminal differentiation markers were all up-regulated versus isotropic control groups. We assessed the in vivo stability of the cartilage formed under different induction regimens. Cartilage formed under spatiotemporal regulation in vitro resisted endochondral ossification, retained the expression of cartilage markers, and remained organized following s.c. implantation in immunocompromised mice. In contrast, the isotropic control groups underwent endochondral ossification. Cartilage formed from hMSCs remained stable and organized in vivo. Spatiotemporal regulation during induction in vitro recapitulated some aspects of native cartilage development, and potentiated the maturation of self-assembling hMSCs into stable and organized cartilage resembling the native articular cartilage.

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Runx2 Regulates Endochondral Ossification in Condyle during Mandibular Advancement

Journal of Dental Research ◽

10.1177/154405910508400211 ◽

2005 ◽

Vol 84 (2) ◽

pp. 166-171 ◽

Cited By ~ 37

Author(s):

G.H. Tang ◽

A.B.M. Rabie

Keyword(s):

Endochondral Ossification ◽

Mandibular Condyle ◽

Mandibular Advancement ◽

New Bone Formation ◽

Sprague Dawley ◽

Condylar Cartilage ◽

Runx2 Expression ◽

Chondrocyte Maturation ◽

Sprague Dawley Rats ◽

Functional Appliances

Runx2 is a transcription factor prerequisite for chondrocyte maturation and osteoblast differentiation. We tested the hypothesis that Runx2 is responsible for signaling chondrocyte maturation and endochondral ossification in the condyle during mandibular advancement. Fifty 35-day-old Sprague-Dawley rats were fitted with functional appliances for 3, 7, 14, 21, and 30 days. Experimental animals with 50 matched controls were labeled with bromodeoxyuridine for evaluation of the invasion of chondroclasts and osteoblasts into condylar cartilage. Mandibular advancement elicited Runx2 expression in condylar cartilage, and subsequently led to an expansion of type X collagen domain in the hypertrophic layer. Stronger Runx2 mRNA signals in subchondral bone corresponded with the increase in the recruitment of osteoblasts and chondroclasts, which preceded the increase of new bone formation in the condyle. Thus, Runx2 mediates chondrocyte terminal maturation and endochondral ossification in the mandibular condyle in response to mandibular advancement.

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Sox9 Family Members Negatively Regulate Maturation and Calcification of Chondrocytes through Up-Regulation of Parathyroid Hormone–related Protein

Molecular Biology of the Cell ◽

10.1091/mbc.e09-03-0227 ◽

2009 ◽

Vol 20 (21) ◽

pp. 4541-4551 ◽

Cited By ~ 48

Author(s):

Katsuhiko Amano ◽

Kenji Hata ◽

Atsushi Sugita ◽

Yoko Takigawa ◽

Koichiro Ono ◽

...

Keyword(s):

Parathyroid Hormone ◽

Endochondral Ossification ◽

Family Members ◽

Chondrocyte Differentiation ◽

Related Protein ◽

Primary Chondrocytes ◽

Chondrocyte Maturation ◽

Parathyroid Hormone Related Protein ◽

Pthrp Expression ◽

Late Stages

Sox9 is a transcription factor that plays an essential role in chondrogenesis and has been proposed to inhibit the late stages of endochondral ossification. However, the molecular mechanisms underlying the regulation of chondrocyte maturation and calcification by Sox9 remain unknown. In this study, we attempted to clarify roles of Sox9 in the late stages of chondrocyte differentiation. We found that overexpression of Sox9 alone or Sox9 together with Sox5 and Sox6 (Sox5/6/9) inhibited the maturation and calcification of murine primary chondrocytes and up-regulated parathyroid hormone–related protein (PTHrP) expression in primary chondrocytes and the mesenchymal cell line C3H10T1/2. Sox5/6/9 stimulated the early stages of chondrocyte proliferation and development. In contrast, Sox5/6/9 inhibited maturation and calcification of chondrocytes in organ culture. The inhibitory effects of Sox5/6/9 were rescued by treating with anti-PTHrP antibody. Moreover, Sox5/6/9 bound to the promoter region of the PTHrP gene and up-regulated PTHrP gene promoter activity. Interestingly, we also found that the Sox9 family members functionally collaborated with Ihh/Gli2 signaling to regulate PTHrP expression and chondrocyte differentiation. Our results provide novel evidence that Sox9 family members mediate endochondral ossification by up-regulating PTHrP expression in association with Ihh/Gli2 signaling.

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Distinct requirements of wls , wnt9a , wnt5b and gpc4 in regulating chondrocyte maturation and timing of endochondral ossification

Developmental Biology ◽

10.1016/j.ydbio.2016.11.016 ◽

2017 ◽

Vol 421 (2) ◽

pp. 219-232 ◽

Cited By ~ 13

Author(s):

Irving TC Ling ◽

Lucie Rochard ◽

Eric C. Liao

Keyword(s):

Endochondral Ossification ◽

Chondrocyte Maturation

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Simultaneous differentiation of articular and transient cartilage: WNT-BMP interplay and its therapeutic implication

The International Journal of Developmental Biology ◽

10.1387/ijdb.190149ab ◽

2020 ◽

Vol 64 (1-2-3) ◽

pp. 203-211

Author(s):

Tathagata Biswas ◽

Akrit P. Jaswal ◽

Upendra S. Yadav ◽

Amitabha Bandyopadhyay

Keyword(s):

Tissue Engineering ◽

Developmental Biology ◽

Endochondral Ossification ◽

Recent Literature ◽

New Paradigm ◽

Treatment Of Osteoporosis ◽

Chondrocyte Maturation ◽

Different Types ◽

Insight Into ◽

And Cartilage

Limb skeleton forms through the process of endochondral ossification. This process of osteogenesis proceeds through an intermediate cartilage template and involves several stages of chondrocyte maturation and eventual bone formation. During the process of endochondral ossification, interplay between BMP and WNT signaling regulate simultaneous differentiation of articular and transient cartilage. In this review, we focus on the recent literature which explores the simultaneous differentiation of these two different types of cartilage. We discuss a new paradigm of developmental biology-inspired tissue engineering of bone and cartilage grafts and provide novel insight into treatment of osteoporosis.

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TBX1 Regulates Chondrocyte Maturation in the Spheno-occipital Synchondrosis

Journal of Dental Research ◽

10.1177/0022034520925080 ◽

2020 ◽

Vol 99 (10) ◽

pp. 1182-1191 ◽

Cited By ~ 1

Author(s):

N. Funato ◽

D. Srivastava ◽

S. Shibata ◽

H. Yanagisawa

Keyword(s):

Digeorge Syndrome ◽

Endochondral Ossification ◽

Transcriptional Activity ◽

Ectopic Expression ◽

Chondrocyte Differentiation ◽

Craniofacial Skeleton ◽

Chondrocyte Maturation ◽

Expression Of Genes ◽

Growth Center ◽

Deficient Mice

The synchondrosis in the cranial base is an important growth center for the craniofacial region. Abnormalities in the synchondroses affect the development of adjacent regions, including the craniofacial skeleton. Here, we report that the transcription factor TBX1, the candidate gene for DiGeorge syndrome, is expressed in mesoderm-derived chondrocytes and plays an essential and specific role in spheno-occipital synchondrosis development by inhibiting the expression of genes involved in chondrocyte hypertrophy and osteogenesis. In Tbx1-deficient mice, the spheno-occipital synchondrosis was completely mineralized at birth. TBX1 interacts with RUNX2, a master molecule of osteoblastogenesis and a regulator of chondrocyte maturation, and suppresses its transcriptional activity. Indeed, deleting Tbx1 triggers accelerated mineralization due to accelerated chondrocyte differentiation, which is associated with ectopic expression of downstream targets of RUNX2 in the spheno-occipital synchondrosis. These findings reveal that TBX1 acts as a regulator of chondrocyte maturation and osteogenesis during the spheno-occipital synchondrosis development. Thus, the tight regulation of endochondral ossification by TBX1 is crucial for the normal progression of chondrocyte differentiation in the spheno-occipital synchondrosis.

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Constitutive E2F1 Overexpression Delays Endochondral Bone Formation by Inhibiting Chondrocyte Differentiation

Molecular and Cellular Biology ◽

10.1128/mcb.23.10.3656-3668.2003 ◽

2003 ◽

Vol 23 (10) ◽

pp. 3656-3668 ◽

Cited By ~ 28

Author(s):

Blanca Scheijen ◽

Marieke Bronk ◽

Tiffany van der Meer ◽

René Bernards

Keyword(s):

Bone Formation ◽

Endochondral Ossification ◽

Bone Growth ◽

Late Phase ◽

Type Ii Collagen ◽

Endochondral Bone Formation ◽

Nodule Formation ◽

Chondrocyte Differentiation ◽

Endochondral Bone ◽

Chondrocyte Maturation

ABSTRACT Longitudinal bone growth results from endochondral ossification, a process that requires proliferation and differentiation of chondrocytes. It has been shown that proper endochondral bone formation is critically dependent on the retinoblastoma family members p107 and p130. However, the precise functional roles played by individual E2F proteins remain poorly understood. Using both constitutive and conditional E2F1 transgenic mice, we show that ubiquitous transgene-driven expression of E2F1 during embryonic development results in a dwarf phenotype and significantly reduced postnatal viability. Overexpression of E2F1 disturbs chondrocyte maturation, resulting in delayed endochondral ossification, which is characterized by reduced hypertrophic zones and disorganized growth plates. Employing the chondrogenic cell line ATDC5, we investigated the effects of enforced E2F expression on the different phases of chondrocyte maturation that are normally required for endochondral ossification. Ectopic E2F1 expression strongly inhibits early- and late-phase differentiation of ATDC5 cells, accompanied by diminished cartilage nodule formation as well as decreased type II collagen, type X collagen, and aggrecan gene expression. In contrast, overexpression of E2F2 or E2F3a results in only a marginal delay of chondrocyte maturation, and increased E2F4 levels have no effect. These data are consistent with the notion that E2F1 is a regulator of chondrocyte differentiation.

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Antxr1, Which is a Target of Runx2, Regulates Chondrocyte Proliferation and Apoptosis

International Journal of Molecular Sciences ◽

10.3390/ijms21072425 ◽

2020 ◽

Vol 21 (7) ◽

pp. 2425 ◽

Cited By ~ 2

Author(s):

Qing Jiang ◽

Xin Qin ◽

Carolina Andrea Yoshida ◽

Hisato Komori ◽

Kei Yamana ◽

...

Keyword(s):

Growth Retardation ◽

Endochondral Ossification ◽

Target Genes ◽

Skeletal Development ◽

Chondrocyte Apoptosis ◽

Wild Type ◽

Chondrocyte Proliferation ◽

Matrix Mineralization ◽

Chondrocyte Maturation ◽

Proliferation And Apoptosis

Antxr1/Tem8 is highly expressed in tumor endothelial cells and is a receptor for anthrax toxin. Mutation of Antxr1 causes GAPO syndrome, which is characterized by growth retardation, alopecia, pseudo-anodontia, and optic atrophy. However, the mechanism underlying the growth retardation remains to be clarified. Runx2 is essential for osteoblast differentiation and chondrocyte maturation and regulates chondrocyte proliferation through Ihh induction. In the search of Runx2 target genes in chondrocytes, we found that Antxr1 expression is upregulated by Runx2. Antxr1 was highly expressed in cartilaginous tissues and was directly regulated by Runx2. In skeletal development, the process of endochondral ossification proceeded similarly in wild-type and Antxr1–/– mice. However, the limbs of Antxr1–/– mice were shorter than those of wild-type mice from embryonic day 16.5 due to the reduced chondrocyte proliferation. Chondrocyte-specific Antxr1 transgenic mice exhibited shortened limbs, although the process of endochondral ossification proceeded as in wild-type mice. BrdU-uptake and apoptosis were both increased in chondrocytes, and the apoptosis-high regions were mineralized. These findings indicated that Antxr1, of which the expression is regulated by Runx2, plays an important role in chondrocyte proliferation and that overexpression of Antxr1 causes chondrocyte apoptosis accompanied by matrix mineralization.

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