scholarly journals Dmrt2 promotes transition of endochondral bone formation by linking Sox9 and Runx2

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Koichiro Ono ◽  
Kenji Hata ◽  
Eriko Nakamura ◽  
Shota Ishihara ◽  
Sachi Kobayashi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Bone Formation ◽  
Skeletal Development ◽  
Endochondral Bone Formation ◽  
Chondrocyte Differentiation ◽  
Endochondral Bone ◽  
Chondrocyte Hypertrophy ◽  
Hypertrophic Chondrocyte ◽  
Delayed Initiation ◽  
Related Transcription Factor

AbstractEndochondral bone formation is fundamental for skeletal development. During this process, chondrocytes undergo multiple steps of differentiation and coordinated transition from a proliferating to a hypertrophic stage, which is critical to advance skeletal development. Here, we identified the transcription factor Dmrt2 (double-sex and mab-3 related transcription factor 2) as a Sox9-inducible gene that promotes chondrocyte hypertrophy in pre-hypertrophic chondrocytes. Epigenetic analysis further demonstrated that Sox9 regulates Dmrt2 expression through an active enhancer located 18 kb upstream of the Dmrt2 gene and that this enhancer’s chromatin status is progressively activated through chondrocyte differentiation. Dmrt2-knockout mice exhibited a dwarf phenotype with delayed initiation of chondrocyte hypertrophy. Dmrt2 augmented hypertrophic chondrocyte gene expression including Ihh through physical and functional interaction with Runx2. Furthermore, Dmrt2 deficiency reduced Runx2-dependent Ihh expression. Our findings suggest that Dmrt2 is critical for sequential chondrocyte differentiation during endochondral bone formation and coordinates the transcriptional network between Sox9 and Runx2.

XBP1S Induces GEP and Enhances Endochondral Bone Growth

2014 ◽  
Vol 926-930 ◽  
pp. 1136-1139
Author(s):  
Feng Jin Guo ◽  
Rong Jiang ◽  
Xiao Feng Han
Keyword(s):  
Growth Factor ◽  
Bone Formation ◽  
Bone Growth ◽  
Ex Vivo ◽  
Skeletal Development ◽  
Endochondral Bone Formation ◽  
Chondrocyte Differentiation ◽  
Endochondral Bone ◽  
Temporal And Spatial

We previously reported that transcription factor XBP1S is upregulated during chondrocyte differentiation and demonstrates the temporal and spatial expression pattern during skeletal development. Herein, we found that XBP1S stimulates chondrocyte differentiation from mesenchymal stem cells in vitro and endochondral ossification ex vivo. In addition, XBP1S activates granulin-epithelin precursor (GEP), a growth factor known to stimulate chondrogenesis, then enhances GEP-stimulated chondrogenesis and endochondral bone formation. Collectively, these findings demonstrate that XBP1S positively regulates endochondral bone formation by activating GEP chondrogenic growth factor.

scholarly journals Regulation of terminal hypertrophic chondrocyte differentiation in Prmt5 mutant mice modeling infantile idiopathic scoliosis

2019 ◽  
Author(s):  
Zhaoyang Liu ◽  
Janani Ramachandran ◽  
Steven A Vokes ◽  
Ryan S Gray
Keyword(s):  
Bone Formation ◽  
Idiopathic Scoliosis ◽  
Age Of Onset ◽  
Endochondral Bone Formation ◽  
Chondrocyte Differentiation ◽  
Respiratory Compromise ◽  
Endochondral Bone ◽  
Hypertrophic Chondrocyte ◽  
Infantile Idiopathic Scoliosis ◽  
Adult Spine

ABSTRACTIdiopathic scoliosis (IS) is the most common type of musculoskeletal defect effecting children and is classified by age of onset, location, and degree of spine curvature. Although rare, the onset of IS during infancy is the more severe and rapidly progressive form of the disease, leading to increased mortality due to significant respiratory compromise. The pathophysiology of IS, in particular for infantile IS, remain elusive. Here, we show that PRMT5 is critical for the regulation of terminal hypertrophic chondrocyte differentiation in the spine and models infantile IS in mouse. Conditional ablation of PRMT5 in osteochondral progenitors led to impaired terminal hypertrophic chondrocyte differentiation and asymmetric defects of endochondral bone formation in the perinatal spine. Analysis of several markers of endochondral ossification revealed increased COLX and Ihh expression and a dramatic reduction of Mmp13 and RUNX2 expression in the intervertebral disc and vertebral growth plate. Furthermore, we demonstrate that PRMT5 function in committed chondrogenic lineages is required for regulation of COLX expression in the adult spine. Together, our results establish PRMT5 as a critical regulator of hypertrophic chondrocyte differentiation and endochondral bone formation in spine development and maintenance.

scholarly journals Runx1 up-regulates chondrocyte to osteoblast lineage commitment and promotes bone formation by enhancing both chondrogenesis and osteogenesis

2020 ◽  
Vol 477 (13) ◽  
pp. 2421-2438 ◽  
Author(s):  
Chen-Yi Tang ◽  
Wei Chen ◽  
Yuan Luo ◽  
Jinjin Wu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Lineage Commitment ◽  
Marker Genes ◽  
Endochondral Bone Formation ◽  
Bone Biology ◽  
Endochondral Bone ◽  
Hypertrophic Chondrocyte ◽  
Related Transcription Factor ◽  
Osteoblast Lineage

One of the fundamental questions in bone biology is where osteoblasts originate and how osteoblast differentiation is regulated. The mechanism underlying which factors regulate chondrocyte to osteoblast lineage commitment remains unknown. Our data showed that Runt-related transcription factor 1 (Runx1) is expressed at different stages of both chondrocyte and osteoblast differentiation. Runx1 chondrocyte-specific knockout (Runx1f/fCol2α1-cre) mice exhibited impaired cartilage formation, decreased bone density, and an osteoporotic phenotype. The expressions of chondrocyte differentiation regulation genes, including Sox9, Ihh, CyclinD1, PTH1R, and hypertrophic chondrocyte marker genes including Col2α1, Runx2, MMP13, Col10α1 in the growth plate were significantly decreased in Runx1f/fCol2α1-cre mice chondrocytes. Importantly, the expression of osteoblast differentiation regulation genes including Osx, Runx2, ATF4, and osteoblast marker genes including osteocalcin (OCN) and osteopontin (OPN) were significantly decreased in the osteoblasts of Runx1f/fCol2α1-cre mice. Notably, our data showed that osteoblast differentiation regulation genes and marker genes are also expressed in chondrocytes and the expressions of these marker genes were significantly decreased in the chondrocytes of Runx1f/fCol2α1-cre mice. Our data showed that chromatin immunoprecipitation (ChIP) and promoter mapping analysis revealed that Runx1 directly binds to the Indian hedgehog homolog (Ihh) promoter to regulate its expression, indicating that Runx1 directly regulates the transcriptional expression of chondrocyte genes. Collectively, we revealed that Runx1 signals chondrocyte to osteoblast lineage commitment and promotes endochondral bone formation through enhancing both chondrogenesis and osteogenesis genes expressions, indicating Runx1 may be a therapeutic target to enhance endochondral bone formation and prevent osteoporosis fractures.

scholarly journals Prolyl Hydroxylase Domain-Containing Protein 3 Gene Expression in Chondrocytes Is Not Essential for Bone Development in Mice

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2200
Author(s):  
Weirong Xing ◽  
Sheila Pourteymoor ◽  
Gustavo A. Gomez ◽  
Yian Chen ◽  
Subburaman Mohan
Keyword(s):  
Gene Expression ◽  
Bone Formation ◽  
Bone Mass ◽  
Trabecular Bone ◽  
Bone Volume ◽  
Endochondral Bone Formation ◽  
Chondrocyte Differentiation ◽  
Trabecular Bone Volume ◽  
Endochondral Bone ◽  
Trabecular Bone Mass

We previously showed that conditional disruption of the Phd2 gene in chondrocytes led to a massive increase in long bone trabecular bone mass. Loss of Phd2 gene expression or inhibition of PHD2 activity by a specific inhibitor resulted in a several-fold compensatory increase in Phd3 expression in chondrocytes. To determine if expression of PHD3 plays a role in endochondral bone formation, we conditionally disrupted the Phd3 gene in chondrocytes by crossing Phd3 floxed (Phd3flox/flox) mice with Col2α1-Cre mice. Loss of Phd3 expression in the chondrocytes of Cre+; Phd3flox/flox conditional knockout (cKO) mice was confirmed by real time PCR. At 16 weeks of age, neither body weight nor body length was significantly different in the Phd3 cKO mice compared to Cre−; Phd3flox/flox wild-type (WT) mice. Areal BMD measurements of total body as well as femur, tibia, and lumbar skeletal sites were not significantly different between the cKO and WT mice at 16 weeks of age. Micro-CT measurements revealed significant gender differences in the trabecular bone volume adjusted for tissue volume at the secondary spongiosa of the femur and the tibia for both genotypes, but no genotype difference was found for any of the trabecular bone measurements of either the femur or the tibia. Trabecular bone volume of distal femur epiphysis was not different between cKO and WT mice. Histology analyses revealed Phd3 cKO mice exhibited a comparable chondrocyte differentiation and proliferation, as evidenced by no changes in cartilage thickness and area in the cKO mice as compared to WT littermates. Consistent with the in vivo data, lentiviral shRNA-mediated knockdown of Phd3 expression in chondrocytes did not affect the expression of markers of chondrocyte differentiation (Col2, Col10, Acan, Sox9). Our study found that Phd2 but not Phd3 expressed in chondrocytes regulates endochondral bone formation, and the compensatory increase in Phd3 expression in the chondrocytes of Phd2 cKO mice is not the cause for increased trabecular bone mass in Phd2 cKO mice.

scholarly journals Smoc1 and Smoc2 regulate bone formation as downstream molecules of Runx2

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yoshifumi Takahata ◽  
Hiromasa Hagino ◽  
Ayaka Kimura ◽  
Mitsuki Urushizaki ◽  
Sachi Kobayashi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Bone Formation ◽  
Rna Sequencing ◽  
Late Stage ◽  
Bone Sialoprotein ◽  
Endochondral Bone Formation ◽  
Endochondral Bone ◽  
Novel Targets ◽  
Essential Transcription Factor

AbstractRunx2 is an essential transcription factor for bone formation. Although osteocalcin, osteopontin, and bone sialoprotein are well-known Runx2-regulated bone-specific genes, the skeletal phenotypes of knockout (KO) mice for these genes are marginal compared with those of Runx2 KO mice. These inconsistencies suggest that unknown Runx2-regulated genes play important roles in bone formation. To address this, we attempted to identify the Runx2 targets by performing RNA-sequencing and found Smoc1 and Smoc2 upregulation by Runx2. Smoc1 or Smoc2 knockdown inhibited osteoblastogenesis. Smoc1 KO mice displayed no fibula formation, while Smoc2 KO mice had mild craniofacial phenotypes. Surprisingly, Smoc1 and Smoc2 double KO (DKO) mice manifested no skull, shortened tibiae, and no fibulae. Endochondral bone formation was also impaired at the late stage in the DKO mice. Collectively, these results suggest that Smoc1 and Smoc2 function as novel targets for Runx2, and play important roles in intramembranous and endochondral bone formation.

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