Publications by authors named "Takako Hattori"

59 Publications

UCP1 expression in the mouse adrenal gland is not upregulated by thermogenic conditions.

Biochem Biophys Res Commun 2021 Aug 12;566:184-189. Epub 2021 Jun 12.

Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8558, Japan. Electronic address:

The uncoupling protein 1 (UCP1) gene is known to be highly expressed in brown adipose tissue (BAT) that functions in thermogenesis. It has been shown that UCP1 mRNA is localized to the mouse adrenal gland, but its significance remains elusive. To explore how UCP1 expression in the adrenal gland is regulated, we generated a reporter knock-in mouse in which the GFP gene was inserted into the UCP1 locus using CRISPR-Cas9 system. Firstly, we confirmed by Western blot analysis UCP1-driven GFP protein expression in interscapular BAT of the knock-in mice kept at 4 °C. Immunohistochemistry showed that GFP protein was detected in the adrenal gland of the knock-in mice. More intense GFP expression was observed in the adrenal medulla than in the cortex of the reporter mice irrespectively of cold exposure. Immunohistochemistry using anti-UCP1 antibody, as well as Western blot analysis verified UCP1 protein expression in the wild-type adrenal medulla. These results suggest that the mouse adrenal gland is a novel organ expressing UCP1 protein and its expression is not upregulated by cold exposure.
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http://dx.doi.org/10.1016/j.bbrc.2021.06.013DOI Listing
August 2021

Cellular communication network factor 3 in cartilage development and maintenance.

J Cell Commun Signal 2021 Jun 14. Epub 2021 Jun 14.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Cellular communication network factor (CCN) 3 is one of the classical members of the CCN family, which are characterized by common molecular structures and multiple functionalities. Although this protein was discovered as a gene product overexpressed in a truncated form in nephroblastoma, recent studies have revealed its physiological roles in the development and homeostasis of mammalian species, in addition to its pathological association with a number of diseases. Cartilage is a tissue that creates most of the bony parts and cartilaginous tissues that constitute the human skeleton, in which CCN3 is also differentially produced to exert its molecular missions therein. In this review article, after the summary of the molecular structure and function of CCN3, recent findings on the regulation of ccn3 expression and the roles of CCN3 in endochondral ossification, cartilage development, maintenance and disorders are introduced with an emphasis on the metabolic regulation and function of this matricellular multifunctional molecule.
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http://dx.doi.org/10.1007/s12079-021-00629-zDOI Listing
June 2021

Bipartite regulation of cellular communication network factor 2 and fibroblast growth factor 1 genes by fibroblast growth factor 1 through histone deacetylase 1 and fork head box protein A1.

J Cell Commun Signal 2021 Mar 4;15(1):81-91. Epub 2021 Jan 4.

Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Fibroblast growth factor 1 (FGF-1) is the first FGF family member, and it induces proliferation of fibroblasts and other types of the cells. However, recent studies are uncovering unexpected functions of this molecule. Our previous study redefined this growth factor as a catabolic molecule produced in cartilage upon metabolic insult. Indeed, FGF-1 was found to repress the gene expression of cellular communication network factor 2 (CCN2), which protects and regenerates cartilage, amplifying its own production through positive feedback regulation. In the present study, we investigated the molecular mechanism of this bipartite CCN2 repression and FGF1 activation by FGF-1 in chondrocytes. Repression of CCN2 and induction of FGF1 in human chondrocytic cells were both partly abolished by valproic acid, an inhibitor of histone deacetylase 1 (HDAC1), indicating the involvement of chromatin remodeling by histone acetylation in this system. In contrast, RNA degradation analysis suggested no contribution of post-transcriptional regulation of the mRNA stability to the effects conferred by FGF-1. Suspecting a regulation by a specific transcription factor, we next sought a candidate in silico from a large dataset. As a result, we found fork head box protein A1 (FOXA1) as the transcription factor that bound to both CCN2 and FGF1 loci. Functional analysis demonstrated that FOXA1 silencing significantly attenuated the CCN2 repression and FGF1 induction caused by FGF1. These findings collectively indicate that the bipartite regulation by FGF-1 is enabled by the combination of chromatin remodeling by HDACs and transcriptional modulation by FOXA1 with unknown transcriptional coactivators of opposite functionalities.
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http://dx.doi.org/10.1007/s12079-020-00600-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7905003PMC
March 2021

CCN3 (NOV) Drives Degradative Changes in Aging Articular Cartilage.

Int J Mol Sci 2020 Oct 13;21(20). Epub 2020 Oct 13.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan.

Aging is a major risk factor of osteoarthritis, which is characterized by the degeneration of articular cartilage. CCN3, a member of the CCN family, is expressed in cartilage and has various physiological functions during chondrocyte development, differentiation, and regeneration. Here, we examine the role of CCN3 in cartilage maintenance. During aging, the expression of mRNA in mouse primary chondrocytes from knee cartilage increased and showed a positive correlation with and mRNA. Increased accumulation of CCN3 protein was confirmed. To analyze the effects of CCN3 , either primary cultured human articular chondrocytes or rat chondrosarcoma cell line (RCS) were used. Artificial senescence induced by HO caused a dose-dependent increase in gene and CCN3 protein expression, along with enhanced expression of and mRNA and proteins, as well as SA-β gal activity. Overexpression of CCN3 also enhanced promoter activity via . Accordingly, the addition of recombinant CCN3 protein to the culture increased the expression of and mRNAs. We have produced cartilage-specific CCN3-overexpressing transgenic mice, and found degradative changes in knee joints within two months. Inflammatory gene expression was found even in the rib chondrocytes of three-month-old transgenic mice. Similar results were observed in human knee articular chondrocytes from patients at both mRNA and protein levels. These results indicate that CCN3 is a new senescence marker of chondrocytes, and the overexpression of CCN3 in cartilage may in part promote chondrocyte senescence, leading to the degeneration of articular cartilage through the induction of p53 and p21.
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http://dx.doi.org/10.3390/ijms21207556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7593953PMC
October 2020

CTGF/CCN2 facilitates LRP4-mediated formation of the embryonic neuromuscular junction.

EMBO Rep 2020 08 17;21(8):e48462. Epub 2020 Jun 17.

Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan.

At the neuromuscular junction (NMJ), lipoprotein-related receptor 4 (LRP4) mediates agrin-induced MuSK phosphorylation that leads to clustering of acetylcholine receptors (AChRs) in the postsynaptic region of the skeletal muscle. Additionally, the ectodomain of LRP4 is necessary for differentiation of the presynaptic nerve terminal. However, the molecules regulating LRP4 have not been fully elucidated yet. Here, we show that the CT domain of connective tissue growth factor (CTGF/CCN2) directly binds to the third beta-propeller domain of LRP4. CTGF/CCN2 enhances the binding of LRP4 to MuSK and facilitates the localization of LRP4 on the plasma membrane. CTGF/CCN2 enhances agrin-induced MuSK phosphorylation and AChR clustering in cultured myotubes. Ctgf-deficient mouse embryos (Ctgf ) have small AChR clusters and abnormal dispersion of synaptic vesicles along the motor axon. Ultrastructurally, the presynaptic nerve terminals have reduced numbers of active zones and mitochondria. Functionally, Ctgf embryos exhibit impaired NMJ signal transmission. These results indicate that CTGF/CCN2 interacts with LRP4 to facilitate clustering of AChRs at the motor endplate and the maturation of the nerve terminal.
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http://dx.doi.org/10.15252/embr.201948462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403661PMC
August 2020

Roles of Interaction between CCN2 and Rab14 in Aggrecan Production by Chondrocytes.

Int J Mol Sci 2020 Apr 16;21(8). Epub 2020 Apr 16.

Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan.

To identify proteins that cooperate with cellular communication network factor 2 (CCN2), we carried out GAL4-based yeast two-hybrid screening using a cDNA library derived from the chondrocytic cell line HCS-2/8. Rab14 GTPase (Rab14) polypeptide was selected as a CCN2-interactive protein. The interaction between CCN2 and Rab14 in HCS-2/8 cells was confirmed using the in situ proximity ligation assay. We also found that CCN2 interacted with Rab14 through its IGFBP-like domain among the four domains in CCN2 protein. To detect the colocalization between CCN2 and Rab14 in the cells in detail, CCN2, wild-type Rab14 (Rab14WT), a constitutive active form (Rab14CA), and a dominant negative form (Rab14DN) of Rab14 were overexpressed in monkey kidney-tissue derived COS7 cells. Ectopically overexpressed Rab14 showed a diffuse cytosolic distribution in COS7 cells; however, when Rab14WT was overexpressed with CCN2, the Rab14WT distribution changed to dots that were evenly distributed within the cytosol, and both Rab14 and CCN2 showed clear colocalization. When Rab14CA was overexpressed with CCN2, Rab14CA and CCN2 also showed good localization as dots, but their distribution was more widespread within cytosol. The coexpression of Rab14DN and CCN2 also showed a dotted codistribution but was more concentrated in the perinuclear area. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the reduction in or mRNA by their respective siRNA significantly enhanced the expression of ER stress markers, and mRNA in HCS-2/8 chondrocytic cells, suggesting that ER and Golgi stress were induced by the inhibition of membrane vesicle transfer via the suppression of CCN2 or Rab14. Moreover, to study the effect of the interaction between CCN2 and its interactive protein Rab14 on proteoglycan synthesis, we overexpressed Rab14WT or Rab14CA or Rab14DN in HCS-2/8 cells and found that the overexpression of Rab14DN decreased the extracellular proteoglycan accumulation more than the overexpression of Rab14WT/CA did in the chondrocytic cells. These results suggest that intracellular CCN2 is associated with Rab14 on proteoglycan-containing vesicles during their transport from the Golgi apparatus to endosomes in chondrocytes and that this association may play a role in proteoglycan secretion by chondrocytes.
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http://dx.doi.org/10.3390/ijms21082769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215643PMC
April 2020

Burden of asthma exacerbations and health care utilization in pediatric patients with asthma in the US and England.

Immun Inflamm Dis 2020 06 28;8(2):236-245. Epub 2020 Mar 28.

Epidemiology, GlaxoSmithKline, Upper Providence, Pennsylvania.

Background: Data on asthma burden in pediatric patients are limited; this real-world study investigated exacerbation frequency and health care resource utilization (HCRU) in pediatric asthma patients from the US and England.

Methods: Data from pediatric patients (aged 6-17 years) in the Optum claims database (US) or Clinical Practice Research Datalink with linkage to Hospital Episode Statistics (England) were analyzed. Patients were categorized into four hierarchical groups: treated asthma (patients with ≥1 baseline asthma medication), severe asthma (plus Global Initiative for Asthma Step 4/5), severe refractory asthma ([SRA] plus ≥2 baseline severe asthma exacerbations), and eosinophilic SRA (SRA plus blood eosinophil count ≥150 cells/µL). Exacerbation frequency and HCRU during the 12 months postindex were described.

Results: Of 151 549 treated asthma patients in the US, 18 086 had severe asthma, 2099 SRA, and 109 eosinophilic SRA. There were 32 893 treated asthma patients in England, of whom 2711 had severe asthma, 265 SRA, and 8 eosinophilic SRA. In the 12 months postindex, ≥1 exacerbation occurred in 12.4% and 10.8% of patients with severe asthma, and 32.6% and 42.6% with SRA in the US and England, respectively. The proportions of patients with ≥1 asthma hospitalization in the 30 days after the first asthma exacerbation were 2.7% and 4.4% (treated), 3.5% and 8.2% (severe asthma), and 6.0% and 16.8% (SRA) in the US and England, respectively.

Conclusion: This study provides insights into current asthma management practices in the US and England and indicates that some patients with severe disease have an unmet need for effective management.
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http://dx.doi.org/10.1002/iid3.299DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7212194PMC
June 2020

Retrotransposons Manipulating Mammalian Skeletal Development in Chondrocytes.

Int J Mol Sci 2020 Feb 25;21(5). Epub 2020 Feb 25.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan.

Retrotransposons are genetic elements that copy and paste themselves in the host genome through transcription, reverse-transcription, and integration processes. Along with their proliferation in the genome, retrotransposons inevitably modify host genes around the integration sites, and occasionally create novel genes. Even now, a number of retrotransposons are still actively editing our genomes. As such, their profound role in the evolution of mammalian genomes is obvious; thus, their contribution to mammalian skeletal evolution and development is also unquestionable. In mammals, most of the skeletal parts are formed and grown through a process entitled endochondral ossification, in which chondrocytes play central roles. In this review, current knowledge on the evolutional, physiological, and pathological roles of retrotransposons in mammalian chondrocyte differentiation and cartilage development is summarized. The possible biological impact of these mobile genetic elements in the future is also discussed.
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http://dx.doi.org/10.3390/ijms21051564DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7084347PMC
February 2020

Circadian production of melatonin in cartilage modifies rhythmic gene expression.

J Endocrinol 2019 Mar 1. Epub 2019 Mar 1.

T Hattori, Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan.

Endochondral ossification, including bone growth and other metabolic events, is regulated by circadian rhythms. Herein, we provide evidence that melatonin has a direct effect on the circadian rhythm of chondrocytes. We detected mRNA expression of the genes which encode the melatonin-synthesizing enzymes AANAT (arylalkylamine N-acetyltransferase) and HIOMT (hydroxyindole O-methyltransferase), as well as the melatonin receptors MT1 and MT2 in mouse primary chondrocytes and cartilage. Production of melatonin was confirmed by mass spectrometric analysis of primary rat and chick chondrocytes. Addition of melatonin to primary mouse chondrocytes caused enhanced cell growth and increased expression of Col2a1, Aggrecan, and Sox9, but inhibited Col10a1 expression in primary BALB/c mouse chondrocytes. Addition of luzindole, an MT1 and MT2 antagonist, abolished these effects. These data indicate that chondrocytes produce melatonin, which regulates cartilage growth and maturation via the MT1 and MT2 receptors. Kinetic analysis showed that melatonin caused rapid upregulation of Aanat, Mt1, Mt2, and Pthrp expression, followed by Sox9 and Ihh. Furthermore, expression of the clock gene Bmal1 was induced, while that of Per1 was downregulated. Chronobiological analysis of synchronized C3H mouse chondrocytes revealed that melatonin induced the cyclic expression of Aanat and modified the cyclic rhythm of Bmal1, Mt1, and Mt2. In contrast, Mt1 and Mt2 showed different rhythms from Bmal1 and Aanat, indicating the existence of different regulatory genes. Our results indicate that exogenous and endogenous melatonin work in synergy in chondrocytes to adjust rhythmic expression to the central suprachiasmatic nucleus clock.
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http://dx.doi.org/10.1530/JOE-19-0022DOI Listing
March 2019

The efficacy and safety of fluticasone/salmeterol compared to fluticasone in children younger than four years of age.

Pediatr Allergy Immunol 2019 03 6;30(2):195-203. Epub 2019 Feb 6.

Clinical Operations Department, GlaxoSmithKline K.K., Tokyo, Japan.

Background: Fluticasone propionate 50 μg/salmeterol xinafoate 25 μg (FP/SAL) is widely used in adults and children with asthma, but there is sparse information on its use in very young children.

Methods: This was a randomized, double-blind, multicentre, controlled trial conducted in children aged 8 months to 4 years. During a 2-week run-in period, they all received FP twice daily. At randomization, they commenced FP/SAL or FP twice daily for 8 weeks. All were then given FP/SAL only, in a 16-week open-label study continuation. Medications were inhaled through an AeroChamber Plus with attached face mask. The primary end-point was mean change in total asthma symptom scores from baseline to the last 7 days of the double-blind period. Analyses were undertaken in all children randomized to treatment and who received at least one dose of study medication.

Results: Three hundred children were randomized 1:1 to receive FP/SAL or FP. Mean change from baseline in total asthma symptom scores was -3.97 for FP/SAL and -3.01 with FP. The between-group difference was not statistically significant (P = 0.21; 95% confidence interval: -2.47, 0.54). No new safety signals were seen with FP/SAL.

Conclusion: This is the first randomized, double-blind study of this size to evaluate FP/SAL in very young children with asthma. FP/SAL did not show superior efficacy to FP; no clear add-on effect of SAL was demonstrated. No clinically significant differences in safety were noted with FP/SAL usage.
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http://dx.doi.org/10.1111/pai.13010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850202PMC
March 2019

Commensal Microbiota Enhance Both Osteoclast and Osteoblast Activities.

Molecules 2018 06 23;23(7). Epub 2018 Jun 23.

Department of Preventive Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.

Recent studies suggest that the commensal microbiota affects not only host energy metabolism and development of immunity but also bone remodeling by positive regulation of osteoclast activity. However, the mechanism of regulation of bone cells by the commensal microbiota has not been elucidated. In this study, 8-week-old specific pathogen-free (SPF) and germ-free (GF) mice were compared in terms of alveolar bones and primary osteoblasts isolated from calvarias. Micro-CT analysis showed that SPF mice had larger body size associated with lower bone mineral density and bone volume fraction in alveolar bones compared with GF mice. Greater numbers of osteoclasts in alveolar bone and higher serum levels of tartrate-resistant acid phosphatase 5b were observed in SPF mice. Tissue extracts from SPF alveolar bone showed higher levels of cathepsin K, indicating higher osteoclast activity. SPF alveolar extracts also showed elevated levels of γ-carboxylated glutamic acid⁻osteocalcin as a marker of mature osteoblasts compared with GF mice. Polymerase chain reaction (PCR) array analysis of RNA directly isolated from alveolar bone showed that in SPF mice, expression of mRNA of , which also acts as an inhibitor of bone mineralization, was strongly enhanced compared with GF mice. Cultured calvarial osteoblasts from SPF mice showed reduced mineralization but significantly enhanced expression of mRNAs of , and decreased ratio of compared with GF mice. Furthermore, PCR array analyses of transcription factors in cultured calvarial osteoblasts showed strongly upregulated expression of . In contrast, was strongly downregulated in SPF osteoblasts. These results suggest that the commensal microbiota prevents excessive mineralization possibly by stimulating osteocalcin expression in osteoblasts, and enhances both osteoblast and osteoclast activity by regulating specific transcription factors.
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http://dx.doi.org/10.3390/molecules23071517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6100304PMC
June 2018

Bioinspired Mineralization Using Chondrocyte Membrane Nanofragments.

ACS Biomater Sci Eng 2018 Feb 16;4(2):617-625. Epub 2018 Jan 16.

Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

Biomineralization involves complex processes and interactions between organic and inorganic matters, which are controlled in part by the cells. The objectives of this study were, first, to perform a systematic and ultrastructural investigation of the initial mineral formation during secondary ossification center of mouse femur based on material science and biology viewpoint, and then develop novel biomaterials for mineralization based on the in vivo findings. First, we identified the very initial mineral deposition at postnatal day 5 (P5) at the medial side of femur epiphysis by nanocomputed tomography. Initial minerals were found in the surroundings of hypertrophic chondrocytes. Interestingly, histological and immunohistochemical analyses showed that initial mineralization until P6 was based on chondrocyte activity only, i.e., it occurred in the absence of osteoblasts. Moreover, electron microscopy-based ultrastructural analysis showed that cell-secreted matrix vesicles were absent in the early steps of osteoblast-independent endochondral ossification. Instead, chondrocyte membrane nanofragments were found in the fibrous matrix surrounding the hypertrophic chondrocytes. EDS analysis and electron diffraction study indicated that cell membrane nanofragments were not mineralized material, and could be the nucleation site for the newly formed calcospherites. The phospholipids in the cell membrane nanofragments could be a source of phosphate for subsequent calcium phosphate formation, which initially was amorphous, and later transformed into apatite crystals. Finally, artificial cell nanofragments were synthesized from ATDC5 chondrogenic cells, and in vitro assays showed that these nanofragments could promote mineral formation. Taken together, these results indicated that cell membrane nanofragments were the nucleation site for mineral formation, and could potentially be used as material for manipulation of biomineralization.
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http://dx.doi.org/10.1021/acsbiomaterials.7b00962DOI Listing
February 2018

Chondrocyte burst promotes space for mineral expansion.

Integr Biol (Camb) 2018 01;10(1):57-66

Department of Biomaterials, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama-shi, Okayama-ken, 700-8525, Okayama, Japan.

Analysis of tissue development from multidisciplinary approaches can result in more integrative biological findings, and can eventually allow the development of more effective bioengineering methods. In this study, we analyzed the initial steps of mineral formation during secondary ossification of mouse femur based on biological and bioengineering approaches. We first found that some chondrocytes burst near the mineralized area. External factors that could trigger chondrocyte burst were then investigated. Chondrocyte burst was shown to be modulated by mechanical and osmotic pressure. A hypotonic solution, as well as mechanical stress, significantly induced chondrocyte burst. We further hypothesized that chondrocyte burst could be associated with space-making for mineral expansion. In fact, ex vivo culture of femur epiphysis in hypotonic conditions, or under mechanical pressure, enhanced mineral formation, compared to normal culture conditions. Additionally, the effect of mechanical pressure on bone formation in vivo was investigated by immobilization of mouse lower limbs to decrease the body pressure onto the joints. The results showed that limb immobilization suppressed bone formation. Together, these results suggest chondrocyte burst as a novel fate of chondrocytes, and that manipulation of chondrocyte burst with external mechano-chemical stimuli could be an additional approach for cartilage and bone tissue engineering.
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http://dx.doi.org/10.1039/c7ib00130dDOI Listing
January 2018

Generation and Analysis of Cartilage-Specific CCN2 Overexpression in Transgenic Mice.

Methods Mol Biol 2017 ;1489:391-403

Advanced Research Center for Oraland Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Recent progress in gene-editing technology has provided a strong impact for improved our understanding of molecular functions in living organisms. Here we describe our method to generate transgene-overexpressing mouse models, which method involves the use of tissue-specific promoters for analyzing a certain molecule (s) in special tissues. The protocol described in this chapter uses the Col2a1 promoter-enhancer, which is known for driving specific and strong transgene expression in cartilage and is based on several of our studies showing a positive role of the connective tissue growth factor (CCN2) in cartilage-bone development and maintenance of articular cartilage. These mice show strongly accelerated endochondral ossification resulting in enhanced bone elongation, as well as resistance to age-related articular degeneration. This protocol also describes how to analyze the molecular mechanisms of these phenomena by use of chondrocytes isolated from CCN2-overexpressing cartilage.
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http://dx.doi.org/10.1007/978-1-4939-6430-7_32DOI Listing
January 2018

Protein Imaging of CCN2 and CCN3 in Living Cells.

Methods Mol Biol 2017 ;1489:211-215

Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Recent progress in molecular imaging technology has had a strong impact on improving our understanding of molecular translocation, receptor internalization, and interactions in living cells. The protocol in this chapter introduces an optimized technique for intracellular localization of CCN2 and CCN3 in live cells, one using GFP-tagged CCN2 and Halo-tagged CCN3.
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http://dx.doi.org/10.1007/978-1-4939-6430-7_20DOI Listing
January 2018

Protocols for Screening for Binding Partners of CCN Proteins: Yeast Two-Hybrid System.

Methods Mol Biol 2017 ;1489:145-154

Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Yeast two-hybrid screening is a powerful method to identify proteins that interact with a protein of interest. CCN2 consists of four domains, and identification of new proteins that bind to individual domains of CCN2 may reveal a variety of CCN2 functions. To identify CCN2-interactive proteins that regulate CCN2 activity, we carried out GAL4-based yeast two-hybrid screening with a cDNA library derived from a chondrocytic cell line, HCS-2/8, with CCN2 cDNA used as a bait. In this chapter, we describe our methods for screening for CCN2 binding partners by this system in detail. This protocol may be applied to other CCN proteins as well.
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http://dx.doi.org/10.1007/978-1-4939-6430-7_15DOI Listing
January 2018

Production of Recombinant CCN2 Protein in Escherichia coli.

Methods Mol Biol 2017 ;1489:77-84

Advanced Research Center for Oraland Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

Recombinant proteins are important tools for understanding molecular functions in vitro. Recent progress in the generation of recombinant proteins is amazing. However, when we plan to produce them, we should choose the best method according to the nature and the use of the target recombinant protein. Degradation and mis-folding are major problems in producing active recombinant CCN2. The method shown in this chapter describes the appropriate conditions under which we can produce CCN2 and its truncated fragments in Escherichia coli.
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http://dx.doi.org/10.1007/978-1-4939-6430-7_8DOI Listing
January 2018

Involvement of multiple CCN family members in platelets that support regeneration of joint tissues.

Mod Rheumatol 2016 Nov 21;26(6):940-949. Epub 2016 Apr 21.

a Department of Biochemistry and Molecular Dentistry , and.

Objectives: Platelet-rich plasma (PRP) has been widely used to enhance the regeneration of damaged joint tissues, such as osteoarthritic and rheumatoid arthritic cartilage. The aim of this study is to clarify the involvement of all of the CCN family proteins that are crucially associated with joint tissue regeneration.

Methods: Cyr61-CTGF-NOV (CCN) family proteins in human platelets and megakaryocytic cells were comprehensively analyzed by Western blotting analysis. Production of CCN family proteins in megakaryocytes in vivo was confirmed by immunofluorescence analysis of mouse bone marrow cells. Effects of CCN family proteins found in platelets on chondrocytes were evaluated by using human chondrocytic HCS-2/8 cells.

Results: Inclusion of CCN2, a mesenchymal tissue regenerator, was confirmed. Of note, CCN3, which counteracts CCN2, was newly found to be encapsulated in platelets. Interestingly, these two family members were not detectable in megakaryocytic cells, but their external origins were suggested. Furthermore, we found for the first time CCN5 and CCN1 that inhibits ADAMTS4 in both platelets and megakaryocytes. Finally, application of a CCN family cocktail mimicking platelets onto HCS-2/8 cells enhanced their chondrocytic phenotype.

Conclusions: Multiple inclusion of CCN1, 2 and 3 in platelets was clarified, which supports the harmonized regenerative potential of PRP in joint therapeutics.
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http://dx.doi.org/10.3109/14397595.2016.1155255DOI Listing
November 2016

Role of CCN2 in Amino Acid Metabolism of Chondrocytes.

J Cell Biochem 2016 Apr 22;117(4):927-37. Epub 2015 Sep 22.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.

CCN2/connective tissue growth factor (CTGF) is a multi-functional molecule that promotes harmonized development and regeneration of cartilage through its matricellular interaction with a variety of extracellular biomolecules. Thus, deficiency in CCN2 supply profoundly affects a variety of cellular activities including basic metabolism. A previous study showed that the expression of a number of ribosomal protein genes was markedly enhanced in Ccn2-null chondrocytes. Therefore, in this study, we analyzed the impact of CCN2 on amino acid and protein metabolism in chondrocytes. Comparative metabolome analysis of the amino acids in Ccn2-null and wild-type mouse chondrocytes revealed stable decreases in the cellular levels of all of the essential amino acids. Unexpectedly, uptake of such amino acids was rather enhanced in Ccn2-null chondrocytes, and the addition of exogenous CCN2 to human chondrocytic cells resulted in decreased amino acid uptake. However, as expected, amino acid consumption by protein synthesis was also accelerated in Ccn2-null chondrocytes. Furthermore, we newly found that expression of two genes encoding two glycolytic enzymes, as well as the previously reported Eno1 gene, was repressed in those cells. Considering the impaired glycolysis and retained mitochondrial membrane potential in Ccn2-null chondrocytes, these findings suggest that Ccn2 deficiency induces amino acid shortage in chondrocytes by accelerated amino acid consumption through protein synthesis and acquisition of aerobic energy. Interestingly, CCN2 was found to capture such free amino acids in vitro. Under physiological conditions, CCN2 may be regulating the levels of free amino acids in the extracellular matrix of cartilage.
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http://dx.doi.org/10.1002/jcb.25377DOI Listing
April 2016

Dual pathways to endochondral osteoblasts: a novel chondrocyte-derived osteoprogenitor cell identified in hypertrophic cartilage.

Biol Open 2015 Apr 16;4(5):608-21. Epub 2015 Apr 16.

Dept. Exp. Medicine I, Nikolaus-Fiebiger Center of Molecular Medicine, University of Erlangen-Nuremberg, 91054 Erlangen, Germany

According to the general understanding, the chondrocyte lineage terminates with the elimination of late hypertrophic cells by apoptosis in the growth plate. However, recent cell tracking studies have shown that murine hypertrophic chondrocytes can survive beyond "terminal" differentiation and give rise to a progeny of osteoblasts participating in endochondral bone formation. The question how chondrocytes convert into osteoblasts, however, remained open. Following the cell fate of hypertrophic chondrocytes by genetic lineage tracing using BACCol10;Cre induced YFP-reporter gene expression we show that a progeny of Col10Cre-reporter labelled osteoprogenitor cells and osteoblasts appears in the primary spongiosa and participates - depending on the developmental stage - substantially in trabecular, endosteal, and cortical bone formation. YFP(+) trabecular and endosteal cells isolated by FACS expressed Col1a1, osteocalcin and runx2, thus confirming their osteogenic phenotype. In searching for transitory cells between hypertrophic chondrocytes and trabecular osteoblasts we identified by confocal microscopy a novel, small YFP(+)Osx(+) cell type with mitotic activity in the lower hypertrophic zone at the chondro-osseous junction. When isolated from growth plates by fractional enzymatic digestion, these cells termed CDOP (chondrocyte-derived osteoprogenitor) cells expressed bone typical genes and differentiated into osteoblasts in vitro. We propose the Col10Cre-labeled CDOP cells mark the initiation point of a second pathway giving rise to endochondral osteoblasts, alternative to perichondrium derived osteoprogenitor cells. These findings add to current concepts of chondrocyte-osteocyte lineages and give new insight into the complex cartilage-bone transition process in the growth plate.
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http://dx.doi.org/10.1242/bio.201411031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434812PMC
April 2015

Exosomes mediate intercellular transfer of pro-fibrogenic connective tissue growth factor (CCN2) between hepatic stellate cells, the principal fibrotic cells in the liver.

Surgery 2014 Sep 2;156(3):548-55. Epub 2014 Jun 2.

Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH; Department of Pediatric Surgery, Nationwide Children's Hospital, Columbus, OH; Department of Surgery, The Ohio State University, Columbus, OH. Electronic address:

Background: Fibrogenic pathways in the liver are principally regulated by hepatic stellate cells (HSC), which produce and respond to fibrotic mediators such as connective tissue growth factor (CCN2). The aim of this study was to determine whether CCN2 is shuttled between HSC in membranous nanovesicles, or "exosomes."

Methods: Exosomes were incubated with HSC after isolation from conditioned medium of control or CCN2-green fluorescent protein (GFP)-transfected primary mouse HSC or human LX-2 HSC. Some exosomes were stained fluorescently with PKH26. HSC co-culture experiments were performed in the presence of GW4869 exosome inhibitor. CCN2 or CCN2-GFP were evaluated by quantitative real-time polymerase chain reaction or Western blot.

Results: HSC-derived exosomes contained CCN2 or CCN2 mRNA, each of which increased in concentration during HSC activation or after transfection of HSC with CCN2-GFP. Exosomes, stained with either PKH26 or purified from CCN2-GFP-transfected cells, were taken up by activated or quiescent HSC resulting in CCN2-GFP delivery, as shown by their direct addition to recipient cells or by the GW4869-dependency of donor HSC.

Conclusion: CCN2 is packaged into secreted, nano-sized exosomes that mediate its intercellular transfer between HSC. Exosomal CCN2 may amplify or fine tune fibrogenic signaling and, in conjunction with other exosome constituents, may have utility as a noninvasive biomarker to assess hepatic fibrosis.
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http://dx.doi.org/10.1016/j.surg.2014.04.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4150742PMC
September 2014

Connective tissue growth factor (CCN2) and microRNA-21 are components of a positive feedback loop in pancreatic stellate cells (PSC) during chronic pancreatitis and are exported in PSC-derived exosomes.

J Cell Commun Signal 2014 Jun 26;8(2):147-56. Epub 2014 Jan 26.

Center for Clinical and Translational Research, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.

Pancreatitis is an inflammatory condition of the pancreas which, in its chronic form, involves tissue destruction, exocrine and endocrine insufficiency, increased risk of pancreatic cancer, and an extensive fibrotic pathology which is due to unrelenting collagen deposition by pancreatic stellate cells (PSC). In response to noxious agents such as alcohol-excessive consumption of which is a major cause of pancreatitis in the West-normally quiescent PSC undergo a phenotypic and functional transition to activated myofibroblasts which produce and deposit collagen at high levels. This process is regulated by connective tissue growth factor (CCN2), expression of which is highly up-regulated in activated PSC. We show that CCN2 production by activated PSC is associated with enhanced expression of microRNA-21 (miR-21) which was detected at high levels in activated PSC in a murine model of alcoholic chronic pancreatitis. A positive feedback loop between CCN2 and miR-21 was identified that resulted in enhancement of their respective expression as well as that of collagen α1(I). Both miR-21 and CCN2 mRNA were present in PSC-derived exosomes, which were characterized as 50-150 nm CD9-positive nano-vesicles. Exosomes from CCN2-GFP- or miR-21-GFP-transfected PSC were taken up by other PSC cultures, as shown by direct fluorescence or qRT-PCR for GFP. Collectively these studies establish miR-21 and CCN2 as participants in a positive feedback loop during PSC activation and as components of the molecular payload in PSC-derived exosomes that can be delivered to other PSC. Thus interactions between cellular or exosomal miR-21 and CCN2 represent novel aspects of fibrogenic regulation in PSC. Summary Chronic injury in the pancreas is associated with fibrotic pathology which is driven in large part by CCN2-dependent collagen production in pancreatic stellate cells. This study shows that CCN2 up-regulation in PSC is associated with increased expression of miR-21 which, in turn, is able to stimulate CCN2 expression further via a positive feedback loop. Additionally miR-21 and CCN2 were identified in PSC-derived exosomes which effected their delivery to other PSC. The cellular and exosomal miR-21-CCN2 axis is a novel component in PSC fibrogenic signaling.
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http://dx.doi.org/10.1007/s12079-014-0220-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4063995PMC
June 2014

CCN2 as a novel molecule supporting energy metabolism of chondrocytes.

J Cell Biochem 2014 May;115(5):854-65

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Department of Oral and Maxillofacial Reconstructive Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.

CCN2/connective tissue growth factor (CTGF) is a unique molecule that promotes both chondrocytic differentiation and proliferation through its matricellular interaction with a number of extracellular biomolecules. This apparently contradictory functional property of CCN2 suggests its certain role in basic cellular activities such as energy metabolism, which is required for both proliferation and differentiation. Comparative metabolomic analysis of costal chondrocytes isolated from wild-type and Ccn2-null mice revealed overall impaired metabolism in the latter. Among the numerous metabolites analyzed, stable reduction in the intracellular level of ATP, GTP, CTP, or UTP was observed, indicating a profound role of CCN2 in energy metabolism. Particularly, the cellular level of ATP was decreased by more than 50% in the Ccn2-null chondrocytes. The addition of recombinant CCN2 (rCCN2) to cultured Ccn2-null chondrocytes partly redeemed the cellular ATP level attenuated by Ccn2 deletion. Next, in order to investigate the mechanistic background that mediates the reduction in ATP level in these Ccn2-null chondrocytes, we performed transcriptome analysis. As a result, several metabolism-associated genes were found to have been up-regulated or down-regulated in the mutant mice. Up-regulation of a number of ribosomal protein genes was observed upon Ccn2 deletion, whereas a few genes required for aerobic and anaerobic ATP production were down-regulated in the Ccn2-null chondrocytes. Among such genes, reduction in the expression of the enolase 1 gene was of particular note. These findings uncover a novel functional role of CCN2 as a metabolic supporter in the growth-plate chondrocytes, which is required for skeletogenesis in mammals.
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http://dx.doi.org/10.1002/jcb.24728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4267909PMC
May 2014

The regenerative effects of CCN2 independent modules on chondrocytes in vitro and osteoarthritis models in vivo.

Bone 2014 Feb 20;59:180-8. Epub 2013 Nov 20.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan. Electronic address:

The role of CCN family proteins has been proven to be of extreme importance in the process of cartilage development and endochondral ossification. The second member, CCN2, consists of 4 conserved modules that interact with a number of cofactors to display multiple functions. Although the potentially therapeutic effect of intact CCN2 on cartilage regeneration has been indicated by a number of studies, the regenerative effect of independent modules comprising CCN2 has never been evaluated before. This study aims to discover a more robust and effective CCN2 derivative to induce regeneration through assessing the effect of CCN2 independent modules on regeneration in vitro and in vivo, in comparison to the full length CCN2. In vitro evaluation using human chondrocytic cells showed a remarkable enhancing effect of several single modules on the gene expression of cartilaginous extracellular matrix components; whereas combinations of 2 or 3 modules rather diminished such effects. Interestingly, combination of all 4 modules redeemed the effect of intact CCN2 in vitro. Suspecting the re-assembly of the 4 modules, interaction among the modules was examined by surface plasmon resonance analysis. However, the results did not support the possible formation of a tetramodular complex. Next, the thrombospondin 1 type 1 repeat module (TSP1), which was found most promising in the experiments in vitro, and the combination of 4 modules were forwarded further to in vivo confirmation using 2 rat osteoarthritis (OA) models. As a result, TSP1 displayed more prominent regenerative effects than intact CCN2 on damaged cartilage. Unexpectedly, the combination of 4 modules showed limited effects in vivo. These results indicate the utility of TSP1 in the regenerative therapeutics of OA. Possible molecular mechanism that enables conditional reconstruction of CCN2 by 4 modules is discussed as well.
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http://dx.doi.org/10.1016/j.bone.2013.11.010DOI Listing
February 2014

E6-AP/UBE3A protein acts as a ubiquitin ligase toward SOX9 protein.

J Biol Chem 2013 Dec 23;288(49):35138-48. Epub 2013 Oct 23.

From the Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku Okayama 700-8525, Japan.

SOX9 is a transcription factor that acts as a key regulator at various stages of cartilage differentiation. There is ample evidence that intracellular SOX9 protein levels are tightly regulated both by sumoylation and by degradation through the ubiquitin-proteasome pathway. Using a proteomics approach, here we report the identification of a SOX9-binding protein, E6-AP/UBE3A, that may act as a ubiquitin ligase toward Sox9. E6-AP bound SOX9 through the region consisting mostly of its high mobility group domain in vitro. In nuclear lysates, FLAG-tagged E6-AP coprecipitated with Sox9 and its high mobility group domain. This finding was estimated using nuclear lysates from a chondrocytic cell line that endogenously expresses E6-AP and SOX9. Accordingly, ectopically expressed E6-AP and SOX9 colocalized in the nucleus. We show that E6-AP ubiquitinates SOX9 in vitro and in vivo and that SOX9 levels are enhanced after addition of the proteasome inhibitor bortezomib. Similar, siRNA knockdown of E6-AP and the E2 ligase Ubc9 increased cellular SOX9 amounts, supporting the notion that SOX9 may be ubiquitinated in hypertrophic chondrocytes by E6-AP and degraded by proteasomes. This is in accordance with the distribution of SOX9 levels, which are high in proliferating and prehypertrophic chondrocytes but low in hypertrophic chondrocytes, whereas E6-AP levels are high in hypertrophic chondrocytes and low in prehypertrophic chondrocytes. Furthermore, E6-AP-deficient mice showed SOX9 accumulation in chondrocytes and the brain. These findings support the concept that E6-AP regulates SOX9 levels in developing cartilage by acting as a ubiquitin ligase.
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http://dx.doi.org/10.1074/jbc.M113.486795DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853265PMC
December 2013

CCN family member 2/connective tissue growth factor (CCN2/CTGF) has anti-aging effects that protect articular cartilage from age-related degenerative changes.

PLoS One 2013 12;8(8):e71156. Epub 2013 Aug 12.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.

To examine the role of connective tissue growth factor CCN2/CTGF (CCN2) in the maintenance of the articular cartilaginous phenotype, we analyzed knee joints from aging transgenic mice (TG) overexpressing CCN2 driven by the Col2a1 promoter. Knee joints from 3-, 14-, 40-, and 60-day-old and 5-, 12-, 18-, 21-, and 24-month-old littermates were analyzed. Ccn2-LacZ transgene expression in articular cartilage was followed by X-gal staining until 5 months of age. Overexpression of CCN2 protein was confirmed through all ages in TG articular cartilage and in growth plates. Radiographic analysis of knee joints showed a narrowing joint space and other features of osteoarthritis in 50% of WT, but not in any of the TG mice. Transgenic articular cartilage showed enhanced toluidine blue and safranin-O staining as well as chondrocyte proliferation but reduced staining for type X and I collagen and MMP-13 as compared with those parameters for WT cartilage. Staining for aggrecan neoepitope, a marker of aggrecan degradation in WT articular cartilage, increased at 5 and 12 months, but disappeared at 24 months due to loss of cartilage; whereas it was reduced in TG articular cartilage after 12 months. Expression of cartilage genes and MMPs under cyclic tension stress (CTS) was measured by using primary cultures of chondrocytes obtained from wild-type (WT) rib cartilage and TG or WT epiphyseal cartilage. CTS applied to primary cultures of mock-transfected rib chondrocytes from WT cartilage and WT epiphyseal cartilage induced expression of Col1a1, ColXa1, Mmp-13, and Mmp-9 mRNAs; however, their levels were not affected in CCN2-overexpressing chondrocytes and TG epiphyseal cartilage. In conclusion, cartilage-specific overexpression of CCN2 during the developmental and growth periods reduced age-related changes in articular cartilage. Thus CCN2 may play a role as an anti-aging factor by stabilizing articular cartilage.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0071156PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3741357PMC
March 2014

Deletion of beta catenin in hypertrophic growth plate chondrocytes impairs trabecular bone formation.

Bone 2013 Jul 6;55(1):102-12. Epub 2013 Apr 6.

Dept. of Experimental Medicine I, University of Erlangen-Nuremberg, Germany.

In order to elucidate the role of β-catenin in hypertrophic cartilage zone of the growth plate, we deleted the β-catenin gene ctnnb1specifically from hypertrophic chondrocytes by mating ctnnb1(fl/fl) mice with BAC-Col10a1-Cre-deleter mice. Surprisingly, this resulted in a significant reduction of subchondral trabecular bone formation in BACCol10Cre; ctnnb1(Δ/Δ) (referred to as Cat-ko) mice, although Cre expression was restricted to hypertrophic chondrocytes. The size of the Col10a1 positive hypertrophic zone was normal, but qRT-PCR revealed reduced expression of Mmp13, and Vegfa in Cat-ko hypertrophic chondrocytes, indicating impaired terminal differentiation. Immunohistological and in situ hybridization analysis revealed the substantial deficiency of collagen I positive mature osteoblasts, but equal levels of osterix-positive cells in the subchondral bone marrow space of Cat-ko mice, indicating that the supply of osteoblast precursor cells was not reduced. The fact that in Cat-ko mice subchondral trabeculae were lacking including their calcified cartilage core indicated a strongly enhanced osteoclast activity. In fact, TRAP staining as well as in situ hybridization analysis of Mmp9 expression revealed denser occupation of the cartilage erosion zone with enlarged osteoclasts as compared to the control growth plate, suggesting increased RANKL or reduced osteoprotegerin (Opg) activity in this zone. This notion was confirmed by qRT-PCR analysis of mRNA extracted from cultured hypertrophic chondrocytes or from whole epiphyses, showing increased Rankl mRNA levels in Cat-ko as compared to control chondrocytes, whereas changes in OPG levels were not significant. These results indicate that β-catenin levels in hypertrophic chondrocytes play a key role in regulating osteoclast activity and trabecular bone formation at the cartilage-bone interface by controlling RANKL expression in hypertrophic chondrocytes.
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http://dx.doi.org/10.1016/j.bone.2013.03.019DOI Listing
July 2013

Cartilage-specific over-expression of CCN family member 2/connective tissue growth factor (CCN2/CTGF) stimulates insulin-like growth factor expression and bone growth.

PLoS One 2013 28;8(3):e59226. Epub 2013 Mar 28.

Department of Biochemistry and Molecular Dentistry, Okayama University Dental School, Okayama, Japan.

Previously we showed that CCN family member 2/connective tissue growth factor (CCN2) promotes the proliferation, differentiation, and maturation of growth cartilage cells in vitro. To elucidate the specific role and molecular mechanism of CCN2 in cartilage development in vivo, in the present study we generated transgenic mice overexpressing CCN2 and analyzed them with respect to cartilage and bone development. Transgenic mice were generated expressing a ccn2/lacZ fusion gene in cartilage under the control of the 6 kb-Col2a1-enhancer/promoter. Changes in cartilage and bone development were analyzed histologically and immunohistologically and also by micro CT. Primary chondrocytes as well as limb bud mesenchymal cells were cultured and analyzed for changes in expression of cartilage-related genes, and non-transgenic chondrocytes were treated in culture with recombinant CCN2. Newborn transgenic mice showed extended length of their long bones, increased content of proteoglycans and collagen II accumulation. Micro-CT analysis of transgenic bones indicated increases in bone thickness and mineral density. Chondrocyte proliferation was enhanced in the transgenic cartilage. In in vitro short-term cultures of transgenic chondrocytes, the expression of col2a1, aggrecan and ccn2 genes was substantially enhanced; and in long-term cultures the expression levels of these genes were further enhanced. Also, in vitro chondrogenesis was strongly enhanced. IGF-I and IGF-II mRNA levels were elevated in transgenic chondrocytes, and treatment of non-transgenic chondrocytes with recombinant CCN2 stimulated the expression of these mRNA. The addition of CCN2 to non-transgenic chondrocytes induced the phosphorylation of IGFR, and ccn2-overexpressing chondrocytes showed enhanced phosphorylation of IGFR. Our data indicates that the observed effects of CCN2 may be mediated in part by CCN2-induced overexpression of IGF-I and IGF-II. These findings indicate that CCN2-overexpression in transgenic mice accelerated the endochondral ossification processes, resulting in increased length of their long bones. Our results also indicate the possible involvement of locally enhanced IGF-I or IGF-II in this extended bone growth.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0059226PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3610707PMC
September 2013

Novel chondrogenic and chondroprotective effects of the natural compound harmine.

Biochimie 2013 Feb 29;95(2):374-81. Epub 2012 Oct 29.

Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.

A significant number of natural compounds have been shown to regulate the behavior of the cells, in collaboration with cellular proteins. CCN2/connective tissue growth factor (CTGF) has been reported to have essential roles in cartilage development, chondrocyte proliferation and differentiation as well as regulation of the extracellular matrix metabolism. Previous studies demonstrated the capability of CCN2 to regenerate surgical defects in articular cartilage of rat knee. Also, transgenic mice over-expressing cartilage-specific CCN2 were shown to be more resistant to aging-related cartilage degradation. We hypothesized that small molecules that induce CCN2 in chondrocytes could be novel candidates to increase the resistance to aging-related cartilage degradation, or even to correct cartilage degenerative changes incurred in OA. Therefore, this study screened a compound library and identified the β-carboline alkaloid harmine as a novel inducer of CCN2 in human chondrocytic HCS-2/8 cells and osteoarthritic articular chondrocytes. Harmine increased the expression of the cartilage markers aggrecan and COL2α1, as well as that of the master regulator of chondrogenesis, SOX-9. Moreover, harmine notably induced chondrogenesis of prechondrocytic ATDC5 cells in micromass cultures. The chondroprotective effect of harmine was investigated under inflammatory condition by stimulation with TNFα, and harmine was shown to ameliorate TNFα-induced decrease in expression of CCN2 and cartilage markers. These findings uncover novel chondrogenic effects of harmine and indicate harmine as a potential drug for prevention and/or repair of cartilage degradation.
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http://dx.doi.org/10.1016/j.biochi.2012.10.016DOI Listing
February 2013

Anti-fibrotic effect of CCN3 accompanied by altered gene expression profile of the CCN family.

J Cell Commun Signal 2013 Mar 14;7(1):11-8. Epub 2012 Oct 14.

Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8525, Japan.

CCN family proteins 2 and 3 (CCN2 and CCN3) belong to the CCN family of proteins, all having a high level of structural similarity. It is widely known that CCN2 is a profibrotic molecule that mediates the development of fibrotic disorders in many different tissues and organs. In contrast, CCN3 has been recently suggested to act as an anti-fibrotic factor in several tissues. This CCN3 action was shown earlier to be exerted by the repression of the CCN2 gene expression in kidney tissue, whereas different findings were obtained for liver cells. Thus, the molecular action of CCN3 yielding its anti-fibrotic effect is still controversial. Here, using a general model of fibrosis, we evaluated the effect of CCN3 overexpression on the gene expression of all of the CCN family members, as well as on that of fibrotic marker genes. As a result, repression of CCN2 gene expression was modest, while type I collagen and α-smooth muscle actin gene expression was prominently repressed. Interestingly, not only CCN2, but also CCN4 gene expression showed a decrease upon CCN3 overexpression. These findings indicate that fibrotic gene induction is under the control of a complex molecular network conducted by CCN family members functioning together.
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http://dx.doi.org/10.1007/s12079-012-0180-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3590363PMC
March 2013
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