PTHrP and Indian hedgehog control differentiation of growth plate chondrocytes at multiple steps

Development ◽  
2002 ◽  
Vol 129 (12) ◽  
pp. 2977-2986 ◽  
Author(s):  
Tatsuya Kobayashi ◽  
Ung-il Chung ◽  
Ernestina Schipani ◽  
Michael Starbuck ◽  
Gerard Karsenty ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Mouse Models ◽  
Articular Surface ◽  
Indian Hedgehog ◽  
Chondrocyte Differentiation ◽  
Proliferating Cells ◽  
Growth Plate Chondrocytes ◽  
The Third ◽  
Mutual Regulation ◽  
Pthrp Receptor

In developing murine growth plates, chondrocytes near the articular surface (periarticular chondrocytes) proliferate, differentiate into flat column-forming proliferating cells (columnar chondrocytes), stop dividing and finally differentiate into hypertrophic cells. Indian hedgehog (Ihh), which is predominantly expressed in prehypertrophic cells, stimulates expression of parathyroid hormone (PTH)-related peptide (PTHrP) which negatively regulates terminal chondrocyte differentiation through the PTH/PTHrP receptor (PPR). However, the roles of PTHrP and Ihh in regulating earlier steps in chondrocyte differentiation are unclear. We present novel mouse models with PPR abnormalities that help clarify these roles. In mice with chondrocyte-specific PPR ablation and mice with reduced PPR expression, chondrocyte differentiation was accelerated not only at the terminal step but also at an earlier step: periarticular to columnar differentiation. In these models, upregulation of Ihh action in the periarticular region was also observed. In the third model in which the PPR was disrupted in about 30% of columnar chondrocytes, Ihh action in the periarticular chondrocytes was upregulated because of ectopically differentiated hypertrophic chondrocytes that had lost PPR. Acceleration of periarticular to columnar differentiation was also noted in this mouse, while most of periarticular chondrocytes retained PPR signaling. These data suggest that Ihh positively controls differentiation of periarticular chondrocytes independently of PTHrP. Thus, chondrocyte differentiation is controlled at multiple steps by PTHrP and Ihh through the mutual regulation of their activities.

scholarly journals Basic Helix-loop-helix Protein DEC1 Promotes Chondrocyte Differentiation at the Early and Terminal Stages

2002 ◽  
Vol 277 (51) ◽  
pp. 50112-50120 ◽  
Author(s):  
Ming Shen ◽  
Eri Yoshida ◽  
Weiqun Yan ◽  
Takeshi Kawamoto ◽  
Ketut Suardita ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Growth Plate ◽  
Chondrogenic Differentiation ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Indian Hedgehog ◽  
Chondrocyte Differentiation ◽  
Growth Plate Chondrocytes ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix

The mRNA level of basic helix-loop-helix transcription factor DEC1 (BHLHB2)/Stra13/Sharp2 was up-regulated during chondrocyte differentiation in cultures of ATDC5 cells and growth plate chondrocytes, and in growth plate cartilagein vivo. Forced expression of DEC1 in ATDC5 cells induced chondrogenic differentiation, and insulin increased this effect of DEC1 overexpression. Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) suppressed DEC1 expression and the differentiation of ATDC5 cells, but DEC1 overexpression antagonized this inhibitory action of PTH/PTHrP. Transforming growth factor-β or bone morphogenetic protein-2, as well as insulin, induced DEC1 expression in ATDC5 cultures where it induced chondrogenic differentiation. In pellet cultures of bone marrow mesenchymal stem cells exposed to transforming growth factor-β and insulin, DEC1 was induced at the earliest stage of chondrocyte differentiation and also at the hypertrophic stage. Overexpression of DEC1 in the mesenchymal cells induced the mRNA expressions of type II collagen, Indian hedgehog, and Runx2, as well as cartilage matrix accumulation; overexpression of DEC1 in growth plate chondrocytes at the prehypertrophic stage increased the mRNA levels of Indian hedgehog, Runx2, and type X collagen, and also increased alkaline phosphatase activity and mineralization. To our knowledge, DEC1 is the first transcription factor that can promote both chondrogenic differentiation and terminal differentiation.

Parathyroid Hormone and Transforming Growth Factor-β1 Coregulate Chondrocyte Differentiation In Vitro

Endocrine ◽  
2000 ◽  
Vol 13 (3) ◽  
pp. 305-313 ◽  
Author(s):  
E. Nasatzky ◽  
E. Azran ◽  
D. D. Dean ◽  
Barbara D. Boyan ◽  
Z. Schwartz
Keyword(s):  
Parathyroid Hormone ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Chondrocyte Differentiation

scholarly journals The transcription factors SP1 and MAZ regulate expression of the parathyroid hormone/parathyroid hormone-related peptide receptor gene

2000 ◽  
Vol 25 (3) ◽  
pp. 309-319 ◽  
Author(s):  
LJ Williams ◽  
AB Abou-Samra
Keyword(s):  
Transcription Factors ◽  
Parathyroid Hormone ◽  
Mutational Analysis ◽  
Receptor Gene ◽  
Dna Interaction ◽  
Osteosarcoma Cell ◽  
Specific Expression ◽  
Related Peptide ◽  
Its Gene ◽  
Pthrp Receptor

The parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor regulates extracellular calcium concentrations and is therefore important for mineral homeostasis. ROS 17/2.8 cells, a rat osteoblast-like osteosarcoma cell line, express the PTH/PTHrP receptor and provide a good model for examining the transcriptional regulation of its gene. The rat PTH/PTHrP receptor gene has two promoters, U1 and U3, which were shown to be important for its expression. Using extracts from ROS 17/2.8 cells, we have demonstrated two regions (termed FP1 and FP2) of nuclear protein/DNA interaction within promoter sequences previously shown to be important for the activity of the U3 promoter. Nuclear extracts from rat 2 fibroblasts, which do not express the PTH/PTHrP receptor, produced one site of protein/DNA interaction which was found at a position on the promoter identical to the position of FP1 produced by a ROS 17/2.8 nuclear extract. Mutation of these two sites of protein/DNA interaction resulted in reduced U3 promoter activity. Furthermore, we have demonstrated that the transcription factors SP1 and MAZ regulate U3 promoter expression and have shown their functional significance using mutational analysis. These data demonstrate that SP1 and MAZ bind to the PTH/PTHrP receptor promoter and that they are involved in cell-specific expression of its gene product.

16. Physiological effects of IDH1 loss-of-function on Chondrocyte Differentiation through Hedgehog Pathway upregulation

2018 ◽  
Author(s):  
Cassie Tyson
Keyword(s):  
Developmental Stages ◽  
Hedgehog Pathway ◽  
Chondrocyte Differentiation ◽  
Loss Of Function ◽  
Wild Type ◽  
Phenotypic Analysis ◽  
Growth Plate Chondrocytes ◽  
Idh Mutations ◽  
Cartilage Tumors ◽  
Deficient Mice

Cartilage tumors are the most common and terminal primary neoplasms in bone. Physiologically, bones formed through endochondral ossification are regulated by the Hedgehog pathway and Parathyroid hormone-like hormone feedback loop. The upregulation of the infamous Hedgehog pathway has been demonstrated in several non-cartilaginous neoplasms. Recently, frequent mutational events of isocitrate dehydrogenase1 (IDH1) were identified in cartilage tumors. In other neoplasms, IDH mutations produces an oncometabolite that can promote HIF1a activation, contributing to tumorigenesis. Currently, the role of IDH1 mutations in cartilage tumors remain unknown. Investigating the physiological aspect of IDH1proves useful in identifying novel therapeutic targets for cartilage tumors. IDH1 deficient and wild-type littermates, were harvested for forelimbs and hindlimbs at various developmental stages for phenotypic analysis via hematoxylin and eosin staining. Histological analysis demonstrated IDH1 homozygous deficient mice at embryonic stages exhibited dwarfism and an elongated layer of hypertrophic chondrocytes. This was verified via immunohistochemistry Type 10 Collagen staining and Quantitative PCR (qPCR) using the chondrocyte terminal differentiation marker Col10a1. Whole skeletons of IDH1 deficient mice were subjected to skeletal double staining which demonstrated delayed mineralization of underdeveloped IDH1 deficient mice contrasted with wild-type littermates. qPCR was performed to examine the status of chondrocyte differentiation through the Hedgehog pathway in cultured primarymouse growth plate chondrocytes. Interestingly, IDH1 deficient non-neoplastic cells revealed significant upregulation of Hedgehog target molecules in IDH1 deficient chondrocytes. As a result, the loss-offunction of IDH1 was identified as a potential impairment of chondrocyte differentiation and a factor towards chondrocyte tumorgenisis.

Expression of parathyroid hormone-related peptide (PTHrP) and PTH/PTHrP receptor in newborn human calvaria osteoblastic cells

1997 ◽  
Vol 136 (6) ◽  
pp. 640-648 ◽  
Author(s):  
Abderrahim Lomri ◽  
Cindy de Pollak ◽  
Michael Sebag ◽  
David Goltzman ◽  
Richard Kremer ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Parathyroid Hormone ◽  
Culture Media ◽  
Receptor Expression ◽  
Osteoblastic Cells ◽  
Pcr Analysis ◽  
Intracellular Camp ◽  
Related Peptide ◽  
Parathyroid Hormone Related Peptide ◽  
Pthrp Receptor

Abstract We examined the expression of parathyroid hormone-related peptide (PTHrP) and its receptor in normal newborn human calvaria osteoblastic (NHCO) cells. Northern blot analysis showed that NHCO cells express a single 1·6 kb transcript of PTHrP, which was increased within 1 h (2x) and peaked at 6 h (7x) after serum treatment. In the culture media, the release of PTHrP peptide was maximally increased (4x) 24 h after the addition of serum, as determined by immunoradiometric assay. NHCO cells exhibited a cytoplasmic immunostaining for PTHrP in the presence of serum, and most PTHrP-positive cells were alkaline phosphatase-negative, suggesting that PTHrP was expressed in undifferentiated cells. Furthermore, RT-PCR analysis showed that both PTHrP and PTH/PTHrP receptor were expressed in NHCO cells in basal conditions or after stimulation with serum. The maximal PTHrP expression induced by serum suppressed PTH/PTHrP receptor expression, suggesting that PTHrP down-regulated its receptor in NHCO cells. Treatment with 10 nm human PTH(1–34—which binds to PTH/PTHrP receptors, increased intracellular cAMP levels and alkaline phosphatase activity, and decreased cell growth, indicating that ligand binding to PTH/PTHrP receptors regulates NHCO cell proliferation and differentiation. The expression and synthesis of PTHrP and the presence of functional PTH/PTHrP receptors suggest a possible paracrine mechanism of action of PTHrP in normal human calvaria osteoblastic cells. European Journal of Endocrinology 136 640–648

scholarly journals A Novel Van91 I Polymorphism in the 1st Intron of the Parathyroid Hormone(PTH)/PTH-Related Peptide(PTHrP) Receptor Gene and Its Effect on the Urinary cAMP Response to PTH.

2000 ◽  
Vol 23 (4) ◽  
pp. 386-389 ◽  
Author(s):  
Masayuki HEISHI ◽  
Hiromitsu TAZAWA ◽  
Takatoshi MATSUO ◽  
Takayuki SARUTA ◽  
Masato HANAOKA ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Receptor Gene ◽  
Related Peptide ◽  
Pthrp Receptor
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