scholarly journals Smpd3Expression in both Chondrocytes and Osteoblasts Is Required for Normal Endochondral Bone Development

2016 ◽  
Vol 36 (17) ◽  
pp. 2282-2299 ◽  
Author(s):  
Jingjing Li ◽  
Garthiga Manickam ◽  
Seemun Ray ◽  
Chun-do Oh ◽  
Hideyo Yasuda ◽  
...  
Keyword(s):  
Bone Development ◽  
Skeletal Development ◽  
Loss Of Function ◽  
Endochondral Bone ◽  
Transgenic Expression ◽  
Phosphodiesterase 3 ◽  
Skeletal Phenotype ◽  
Metabolizing Enzyme ◽  
Bone Abnormalities ◽  
And Cartilage

Sphingomyelin phosphodiesterase 3 (SMPD3), a lipid-metabolizing enzyme present in bone and cartilage, has been identified to be a key regulator of skeletal development. A homozygous loss-of-function mutation called fragilitas ossium (fro) in theSmpd3gene causes poor bone and cartilage mineralization resulting in severe congenital skeletal deformities. Here we show thatSmpd3expression in ATDC5 chondrogenic cells is downregulated by parathyroid hormone-related peptide through transcription factor SOX9. Furthermore, we show that transgenic expression ofSmpd3in the chondrocytes offro/fromice corrects the cartilage but not the bone abnormalities. Additionally, we report the generation ofSmpd3flox/floxmice for the tissue-specific inactivation ofSmpd3using the Cre-loxPsystem. We found that the skeletal phenotype inSmpd3flox/flox; Osx-Cremice, in which theSmpd3gene is ablated in both late-stage chondrocytes and osteoblasts, closely mimics the skeletal phenotype infro/fromice. On the other hand,Smpd3flox/flox;Col2a1-Cremice, in which theSmpd3gene is knocked out in chondrocytes only, recapitulate thefro/fromouse cartilage phenotype. This work demonstrates thatSmpd3expression in both chondrocytes and osteoblasts is required for normal endochondral bone development.

scholarly journals Microarray Analyses of Gene Expression during Chondrocyte Differentiation Identifies Novel Regulators of Hypertrophy

2005 ◽  
Vol 16 (11) ◽  
pp. 5316-5333 ◽  
Author(s):  
Claudine G. James ◽  
C. Thomas G. Appleton ◽  
Veronica Ulici ◽  
T. Michael Underhill ◽  
Frank Beier
Keyword(s):  
Gene Expression ◽  
Bone Development ◽  
Skeletal Development ◽  
Expression Patterns ◽  
Chondrocyte Differentiation ◽  
Endochondral Bone ◽  
Temporal Gene Expression ◽  
Affymetrix Microarrays ◽  
Time Period ◽  
And Cluster Analysis

Ordered chondrocyte differentiation and maturation is required for normal skeletal development, but the intracellular pathways regulating this process remain largely unclear. We used Affymetrix microarrays to examine temporal gene expression patterns during chondrogenic differentiation in a mouse micromass culture system. Robust normalization of the data identified 3300 differentially expressed probe sets, which corresponds to 1772, 481, and 249 probe sets exhibiting minimum 2-, 5-, and 10-fold changes over the time period, respectively. GeneOntology annotations for molecular function show changes in the expression of molecules involved in transcriptional regulation and signal transduction among others. The expression of identified markers was confirmed by RT-PCR, and cluster analysis revealed groups of coexpressed transcripts. One gene that was up-regulated at later stages of chondrocyte differentiation was Rgs2. Overexpression of Rgs2 in the chondrogenic cell line ATDC5 resulted in accelerated hypertrophic differentiation, thus providing functional validation of microarray data. Collectively, these analyses provide novel information on the temporal expression of molecules regulating endochondral bone development.

scholarly journals Notch Signaling in Skeletal Development, Homeostasis and Pathogenesis

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 332 ◽  
Author(s):  
Jennifer T. Zieba ◽  
Yi-Ting Chen ◽  
Brendan H. Lee ◽  
Yangjin Bae
Keyword(s):  
Notch Signaling ◽  
Cell Fate ◽  
Human Genetics ◽  
Skeletal Development ◽  
Gene Activation ◽  
Fracture Repair ◽  
Loss Of Function ◽  
Age Related ◽  
Complex Process ◽  
And Cartilage

Skeletal development is a complex process which requires the tight regulation of gene activation and suppression in response to local signaling pathways. Among these pathways, Notch signaling is implicated in governing cell fate determination, proliferation, differentiation and apoptosis of skeletal cells-osteoblasts, osteoclasts, osteocytes and chondrocytes. Moreover, human genetic mutations in Notch components emphasize the critical roles of Notch signaling in skeletal development and homeostasis. In this review, we focus on the physiological roles of Notch signaling in skeletogenesis, postnatal bone and cartilage homeostasis and fracture repair. We also discuss the pathological gain- and loss-of-function of Notch signaling in bone and cartilage, resulting in osteosarcoma and age-related degenerative diseases, such as osteoporosis and osteoarthritis. Understanding the physiological and pathological function of Notch signaling in skeletal tissues using animal models and human genetics will provide new insights into disease pathogenesis and offer novel approaches for the treatment of bone/cartilage diseases.

scholarly journals A cell-autonomous requirement for neutral sphingomyelinase 2 in bone mineralization

2011 ◽  
Vol 194 (2) ◽  
pp. 277-289 ◽  
Author(s):  
Zohreh Khavandgar ◽  
Christophe Poirier ◽  
Christopher J. Clarke ◽  
Jingjing Li ◽  
Nicholas Wang ◽  
...  
Keyword(s):  
Bone Mineralization ◽  
Skeletal Development ◽  
Specific Expression ◽  
Neutral Sphingomyelinase ◽  
Phosphodiesterase 3 ◽  
A Cell ◽  
Endocrine Factors ◽  
The Brain ◽  
Bone Abnormalities

A deletion mutation called fro (fragilitas ossium) in the murine Smpd3 (sphingomyelin phosphodiesterase 3) gene leads to a severe skeletal dysplasia. Smpd3 encodes a neutral sphingomyelinase (nSMase2), which cleaves sphingomyelin to generate bioactive lipid metabolites. We examined endochondral ossification in embryonic day 15.5 fro/fro mouse embryos and observed impaired apoptosis of hypertrophic chondrocytes and severely undermineralized cortical bones in the developing skeleton. In a recent study, it was suggested that nSMase2 activity in the brain regulates skeletal development through endocrine factors. However, we detected Smpd3 expression in both embryonic and postnatal skeletal tissues in wild-type mice. To investigate whether nSMase2 plays a cell-autonomous role in these tissues, we examined the in vitro mineralization properties of fro/fro osteoblast cultures. fro/fro cultures mineralized less than the control osteoblast cultures. We next generated fro/fro;Col1a1-Smpd3 mice, in which osteoblast-specific expression of Smpd3 corrected the bone abnormalities observed in fro/fro embryos without affecting the cartilage phenotype. Our data suggest tissue-specific roles for nSMase2 in skeletal tissues.

scholarly journals Raf Kinases Are Essential for Phosphate Induction of ERK1/2 Phosphorylation in Hypertrophic Chondrocytes and Normal Endochondral Bone Development

2017 ◽  
Vol 292 (8) ◽  
pp. 3164-3171 ◽  
Author(s):  
Garyfallia Papaioannou ◽  
Elizabeth T. Petit ◽  
Eva S. Liu ◽  
Manuela Baccarini ◽  
Catrin Pritchard ◽  
...  
Keyword(s):  
Growth Plate ◽  
Vascular Invasion ◽  
Bone Development ◽  
Skeletal Development ◽  
Hypertrophic Chondrocytes ◽  
Chondrocyte Apoptosis ◽  
Caspase 9 ◽  
Endochondral Bone ◽  
Hypertrophic Chondrocyte

Hypophosphatemia causes rickets by impairing hypertrophic chondrocyte apoptosis. Phosphate induction of MEK1/2-ERK1/2 phosphorylation in hypertrophic chondrocytes is required for phosphate-mediated apoptosis and growth plate maturation. MEK1/2 can be activated by numerous molecules including Raf isoforms. A- and B-Raf ablation in chondrocytes does not alter skeletal development, whereas ablation of C-Raf decreases hypertrophic chondrocyte apoptosis and impairs vascularization of the growth plate. However, ablation of C-Raf does not impair phosphate-induced ERK1/2 phosphorylation in vitro, but leads to rickets by decreasing VEGF protein stability. To determine whether Raf isoforms are required for phosphate-induced hypertrophic chondrocyte apoptosis, mice lacking all three Raf isoforms in chondrocytes were generated. Raf deletion caused neonatal death and a significant expansion of the hypertrophic chondrocyte layer of the growth plate, accompanied by decreased cleaved caspase-9. This was associated with decreased phospho-ERK1/2 immunoreactivity in the hypertrophic chondrocyte layer and impaired vascular invasion. These data further demonstrated that Raf kinases are required for phosphate-induced ERK1/2 phosphorylation in cultured hypertrophic chondrocytes and perform essential, but partially redundant roles in growth plate maturation.

scholarly journals Comprehensive series of Irx cluster mutants reveals diverse roles in facial cartilage development

Development ◽  
2021 ◽  
Author(s):  
D'Juan T. Farmer ◽  
Punam Patel ◽  
Rachelle Choi ◽  
Chih-Yu Liu ◽  
J. Gage Crump
Keyword(s):  
Function Analysis ◽  
Skeletal Development ◽  
Proper Function ◽  
Loss Of Function ◽  
Facial Skeleton ◽  
Cartilage Development ◽  
The Face ◽  
Vertebrate Skeleton ◽  
And Cartilage

Proper function of the vertebrate skeleton requires the development of distinct articulating embryonic cartilages. Irx transcription factors are arranged in co-regulated clusters that are expressed in the developing skeletons of the face and appendages. IrxB cluster genes are required for the separation of toes in mice and formation of the hyoid joint in zebrafish, yet whether Irx genes had broader roles in skeletal development remained unclear. Here we perform a comprehensive loss-of-function analysis of all 11 Irx genes in zebrafish. We uncover conserved requirements for IrxB genes in formation of the fish and mouse scapula. In the face, we find a requirement for IrxAb genes and irx7 in formation of anterior neural crest precursors of the jaw, and for IrxBa genes in formation of endodermal pouches and gill cartilages. We also observe extensive joint loss and cartilage fusions in animals with combinatorial losses of Irx clusters, with in vivo imaging revealing that at least some of these fusions arise through inappropriate chondrogenesis. Our analysis reveals diverse roles for Irx genes in the formation and later segmentation of the facial skeleton.

scholarly journals Histone Deacetylases in Bone Development and Skeletal Disorders

2015 ◽  
Vol 95 (4) ◽  
pp. 1359-1381 ◽  
Author(s):  
Elizabeth W. Bradley ◽  
Lomeli R. Carpio ◽  
Andre J. van Wijnen ◽  
Meghan E. McGee-Lawrence ◽  
Jennifer J. Westendorf
Keyword(s):  
Histone Deacetylases ◽  
Bone Development ◽  
Skeletal Development ◽  
Cancer Therapeutics ◽  
Bone Fragility ◽  
Future Research ◽  
Loss Of Function ◽  
Mineral Density ◽  
United States Food ◽  
Development And Aging

Histone deacetylases (Hdacs) are conserved enzymes that remove acetyl groups from lysine side chains in histones and other proteins. Eleven of the 18 Hdacs encoded by the human and mouse genomes depend on Zn2+ for enzymatic activity, while the other 7, the sirtuins (Sirts), require NAD2+. Collectively, Hdacs and Sirts regulate numerous cellular and mitochondrial processes including gene transcription, DNA repair, protein stability, cytoskeletal dynamics, and signaling pathways to affect both development and aging. Of clinical relevance, Hdacs inhibitors are United States Food and Drug Administration-approved cancer therapeutics and are candidate therapies for other common diseases including arthritis, diabetes, epilepsy, heart disease, HIV infection, neurodegeneration, and numerous aging-related disorders. Hdacs and Sirts influence skeletal development, maintenance of mineral density and bone strength by affecting intramembranous and endochondral ossification, as well as bone resorption. With few exceptions, inhibition of Hdac or Sirt activity though either loss-of-function mutations or prolonged chemical inhibition has negative and/or toxic effects on skeletal development and bone mineral density. Specifically, Hdac/Sirt suppression causes abnormalities in physiological development such as craniofacial dimorphisms, short stature, and bone fragility that are associated with several human syndromes or diseases. In contrast, activation of Sirts may protect the skeleton from aging and immobilization-related bone loss. This knowledge may prolong healthspan and prevent adverse events caused by epigenetic therapies that are entering the clinical realm at an unprecedented rate. In this review, we summarize the general properties of Hdacs/Sirts and the research that has revealed their essential functions in bone forming cells (e.g., osteoblasts and chondrocytes) and bone resorbing osteoclasts. Finally, we offer predictions on future research in this area and the utility of this knowledge for orthopedic applications and bone tissue engineering.

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