Faculty Profiles - TAKIGAWA Masaharu

Papers - TAKIGAWA Masaharu

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CCN2遺伝子関連ノンコーディングRNAの軟骨細胞様HCS-2/8細胞における発現

大河原敏博, 久保田聡, 川木晴美, 近藤誠二, 佐々木朗, 滝川正春

岡山歯学会雑誌 27 ( 1 ) 63 - 63 2008.6

CCNファミリー2/結合組織成長因子(CCN2/CTGF)が骨芽細胞において骨形成因子(BMP)-2刺激による骨芽細胞分化を修飾する

前田あずさ, 西田崇, 川木晴美, 久保田聡, 窪木拓男, 滝川正春

岡山歯学会雑誌 27 ( 1 ) 63 - 64 2008.6

Transcriptional regulation of chondrogenesis by coactivator Tip60 via chromatin association with Sox9 and Sox5

Takako Hattori, Francoise Coustry, Shelley Stephens, Heidi Eberspaecher, Masaharu Takigawa, Hideyo Yasuda, Benoit de Crombrugghe

NUCLEIC ACIDS RESEARCH 36 ( 9 ) 3011 - 3024 2008.5

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Sox9 is a transcription factor of the SRY family required for several steps of chondrogenesis. It activates the expression of various chondrocyte-specific genes, but the mechanisms and role of cofactors involved in Sox9-regulated gene transcription are not fully understood. Here, we report on the characterization of a Tat interactive protein-60 (Tip60) as Sox9-associated protein identified in a yeast two-hybrid screen. Both in vitro and in vivo assays confirmed the specificity of interactions between Sox9 and Tip60 including the existence of an endogenous complex containing both polypeptides in chondrocytes. Gel shift assays showed the presence of a complex containing Sox9, Tip60 and the DNA of an enhancer region of the Col2a1 promoter. Reporter assays using a Col2a1 promoter with multimerized Col2a1 Sox9-binding sites indicated that Tip60 enhanced the transcriptional activity of Sox9. A larger Col2a1 promoter showed that Tip60 increased the activity of this promoter in the presence of both Sox9 and Sox5. Ectopic expression of Sox9 and transient-cotransfection with Tip60 in COS7 cells showed a more diffuse subnuclear colocalization, suggesting changes in the chromatin structure. Chromatin immunoprecipitation assays showed that Tip60, Sox9 and Sox5 associated with the same Col2a1 enhancer region. Consistent with a role of Tip60 in chondrogenesis, addition of Tip60 siRNA to limb-bud micromass cultures delayed chondrocyte differention. Tip60 enhances acetylation of Sox9 mainly through K61, 253, 398 residues; however, the K61/253/398A mutant of Sox9 still exhibited enhanced transcriptional activity by Tip60. Our results support the hypothesis that Tip60 is a coactivator of Sox9 in chondrocytes.

DOI： 10.1093/nar/gkn150

Interleukin-4 downregulates the cyclic tensile stress-induced matrix metalloproteinases-13 and cathepsin B expression by rat normal chondrocytes

Hideyuki Doi, Keiichiro Nishida, Masanori Yorimitsu, Takamitsu Komiyama, Yasutaka Kadota, Tomonori Tetsunaga, Aki Yoshida, Satoshi Kubota, Masaharu Takigawa, Toshifumi Ozaki

ACTA MEDICA OKAYAMA 62 ( 2 ) 119 - 126 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：OKAYAMA UNIV MED SCHOOL

Mechanical stress plays a key role in the pathogenesis of cartilage destruction seen in osteoarthritis (OA). We investigated the effect of cyclic tensile stress (CTS) on the anabolic and catabolic gene expression of rat cultured normal chondrocytes using the Flexercell strain unit. The effects of interleukin (IL)-4, a chondroprotective cytokine, on the changes in gene expression induced by CTS were also investigated. CTS (7% elongation at 0.5 Hz) for 24 h did not affect the expression of aggrecan and type 11 collagen, whereas CTS significantly upregulated matrix metalloproteinase (MMP)-13 and cathepsin B mRNA expression by chondrocytes. IL-1 beta expression was also significantly upregulated by CTS up to 12 h. The upregulation of MMP-13 was observed at 3 h, which was earlier than that of IL-1 beta. Furthermore, pre-treatment with IL-4 (10 ng/ml) suppressed both MMP-13 and cathepsin B induction by mechanical stress, as well as CTS-induced IL-1 beta expression. Our results suggest that IL-4 might have a therapeutic value in the treatment of OA by downregulation of mechanical stress-induced MMP-13 and cathepsin B expression by chondrocytes.

Connective tissue growth factor is overexpressed in muscles of human muscular dystrophy

Guilian Sun, Kazuhiro Haginoya, Yanling Wu, Yoko Chiba, Tohru Nakanishi, Akira Onuma, Yuko Sato, Masaharu Takigawa, Kazuie Iinuma, Shigeru Tsuchiya

JOURNAL OF THE NEUROLOGICAL SCIENCES 267 ( 1-2 ) 48 - 56 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The detailed process of how dystrophic muscles are replaced by fibrotic tissues is unknown. In the present study, the immunolocalization and mRNA expression of connective tissue growth factor (CTGF) in muscles from normal and dystrophic human muscles were examined with the goal of elucidating the pathophysiological function of CTGF in muscular dystrophy. Biopsies of frozen muscle from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy, congenital muscular dystrophy, spinal muscular atrophy, congenital myopathy were analyzed using anti-CTGF polyclonal antibody. Reverse transcription-polymerase chain reaction (RT-PCR) was also performed to evaluate the expression of CTGF mRNA in dystrophic muscles. In normal muscle, neuromuscular junctions and vessels were CTGF-immunopositive, which suggests a physiological role for CTGF in these sites. In dystrophic muscle, CTGF immunoreactivity was localized to muscle fiber basal lamina, regenerating fibers, and the interstitium. Triple immunolabeling revealed that activated fibroblasts were immunopositive for CTGF and transforming growth factor-betal (TGF-beta1). RT-PCR analysis revealed increased levels of CTGF mRNA in the muscles of DMD) patients. Co-localization of TGF-beta1 and CTGF in activated fibroblasts suggests that CTGF expression is regulated by TGF-beta1 through a paracrine/autocrine mechanism. In conclusion, TGF-beta1-CTGF pathway may play a role in the fibrosis that is commonly observed in muscular dystrophy. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jns.2007.09.043

Effects of alendronate and pamidronate on cultured rat metatarsal bones: Failure to prevent dexamethasone-induced growth retardation

Terhi J. Heino, Andrei S. Chagin, Masaharu Takigawa, Lars Savendahl

BONE 42 ( 4 ) 702 - 709 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Bisphosphonates are widely used anti-resorptive drugs in the adult population. In children, their use has mainly been limited to patients with osteogenesis imperfecta. However, the powerful effects of bisphosphonates on bone turnover have raised concern about their long-term effects on the growing skeleton.
We aimed to study the effects of two commonly used bisphosphonates, alendronate (Aln) and pamidronate (Pam) on normal bone growth as well as their potential to prevent glucocorticoid-induced growth retardation.
Effects on bone growth were studied in fetal rat metatarsal bones (day E20) that were cultured for 5-47 days and measured every 2-7 days. Cellular mechanisms were investigated in metatarsal bones and also in the human chondrocytic cell line HCS-2/8. Chondrocyte viability (WST-1), proliferation (BrdU incorporation), differentiation (collagen type X immunohistochemistry) and apoptosis (TUNEL and Cell Death ELISA) were determined.
At a clinically relevant concentration of bisphosphonates (1 mu M), metatarsal bone growth was stimulated by both Aln (p<0.001 for length and p < 0.05 for width) and Pam (p < 0.05 for both length and width) from day 19 of culture. The growth-stimulatory effect was associated with increased chondrocyte proliferation (+21% with Aln and +24% with Pam), while cell differentiation and apoptosis were not affected. Despite the finding that both Aln and Pam (1 mu M) rescued HCS-2/8 cells from undergoing dexamethasone-induced apoptosis, neither of them was able to prevent dexamethasone-induced growth retardation of fetal rat metatarsal bones.
Aln and Pam have the capacity to stimulate the growth of cultured fetal rat metatarsal bones; an effect associated with increased proliferation of growth plate chondrocytes. Our experimental data suggest that bisphosphonates are ineffective in preventing glucocorticoid-induced growth retardation. Nevertheless, based on our in vitro data, both Aln and Pam appear safe to use in growing children, at least with regard to their effects on linear bone growth. (c) 2008 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2008.01.001

Novel transcription factor-like function of human matrix metalloproteinase 3 regulating the CTGF/CCN2 gene

Takanori Eguchi, Satoshi Kubota, Kazumi Kawata, Yoshiki Mukudai, Junji Uehara, Toshihiro Ohgawara, Soichiro Ibaragi, Akira Sasaki, Takuo Kuboki, Masaharu Takigawa

MOLECULAR AND CELLULAR BIOLOGY 28 ( 7 ) 2391 - 2413 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC MICROBIOLOGY

Matrix metalloproteinase 3 (MMP3) is well known as a secretory endopeptidase that degrades extracellular matrices. Recent reports indicated the presence of MMPs in the nucleus (A. J. Kwon et al., FASEB J. 18:690-692, 2004); however, its function has not been well investigated. Here, we report a novel function of human nuclear MMP3 as a trans regulator of connective tissue growth factor (CCN2/CTGF). Initially, we cloned MMP3 cDNA as a DNA-binding factor for the CCN2/CTGF gene. An interaction between MMP3 and transcription enhancer dominant in chondrocytes (TRENDIC) in the CCN2/CTGF promoter was confirmed by a gel shift assay and chromatin immunoprecipitation. The CCN2/CTGF promoter was activated by overexpressed MMP3, whereas a TRENDIC mutant promoter lost the response. Also, the knocking down of MMP3 suppressed CCN2/CTGF expression. By cytochemical and histochemical analyses, MMP3 was detected in the nuclei of chondrocytic cells in culture and also in the nuclei of normal and osteoarthritic chondrocytes in vivo. The nuclear translocation of externally added recombinant MMP3 and six putative nuclear localization signals in MMP3 also were shown. Furthermore, we determined that heterochromatin protein gamma coordinately regulates CCN2/CTGF by interacting with MMP3. The involvement of this novel role of MMP3 in the development, tissue remodeling, and pathology of arthritic diseases through CCN2/CTGF regulation thus is suggested.

DOI： 10.1128/MCB.01288-07

Plasma connective tissue growth factor is a novel potential biomarker of cardiac dysfunction in patients with chronic heart failure

Norimichi Koitabashi, Masashi Arai, Kazuo Niwano, Atai Watanabe, Michiko Endoh, Masahiko Suguta, Tomoyuki Yokoyama, Hiroshi Tada, Takuji Toyama, Hitoshi Adachi, Shigeto Naito, Shigeru Oshima, Takashi Nishida, Satoshi Kubota, Masaharu Takigawa, Masahiko Kurabayashi

EUROPEAN JOURNAL OF HEART FAILURE 10 ( 4 ) 373 - 379 2008.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Background: Connective tissue growth factor (CTGF) has been recently reported as a mediator of myocardial fibrosis; however, the significance of plasma CTGF concentration has not been evaluated in patients with heart failure. The aim of this study was to investigate the clinical utility of plasma CTGF concentration for the diagnosis of heart failure.
Methods and results: We evaluated fifty-two patients with chronic heart failure. The plasma concentration of CTGF and other markers of fibrosis were assessed and compared with clinical and echocardiographic data. Plasma CTGF was significantly elevated in symptomatic patients in proportion to their NYHA classes and was significantly correlated with plasma brain natriuretic peptide (BNP) concentration (r=0.395, P<0.01). Plasma CTGF was also correlated with plasma transforming growth factor beta (TGF-beta) (r=0.512, P<0.01), matrix metalloproteinase (MMP)-2 (r=0.391, P<0.05) and tissue inhibitor of MMP (TIMP)-2 (r=0.354, P<0.05) concentrations. Interestingly, plasma CTGF was correlated with E/E' value evaluated by tissue Doppler echocardiography (r=0.593, P=0.012), but not with systolic function and left ventricular mass.
Conclusion: Our study suggests that plasma CTGF concentration is a novel diagnostic marker for cardiac dysfunction and may provide additional specific information about myocardial fibrosis in chronic heart failure patients. (C) 2008 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ejheart.2008.02.011

Functional requirement of CCN2 for intramembranous bone formation in embryonic mice

Harumi Kawaki, Satoshi Kubota, Akiko Suzuki, Tomohiro Yamada, Tatsushi Matsumura, Toshiko Mandal, Mayumi Yao, Takeyasu Maeda, Karen M. Lyons, Masaharu Takigawa

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 366 ( 2 ) 450 - 456 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

CCN2 is best known as a promoter of chondrocyte differentiation among the CCN family members, and Ccn2 null mutant mice display skeletal dysmorphisms. However, little is known concerning the roles of CCN2 during bone formation. We herein present a comparative analysis of wild-type and Ccn2 null mice to investigate the roles of CCN2 in bone development. Multiple histochemical methods were employed to analyze the effects of CCN2 deletion in vivo, and effects of CCN2 on the osteogenic response were evaluated with the isolated and cultured osteoblasts. As a result, we found a drastic reduction of the osteoblastic phenotype in Ccn2 null mutants. Importantly, addition of exogenous CCN2 promoted every step of osteoblast differentiation and rescued the attenuated activities of the Ccn2 null osteoblasts. These results suggest that CCN2 is required not only for the regulation of cartilage and subsequent events, but also for the normal intramembranous bone development. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2007.11.155

Inhibition of tumor-stromal interaction through HGF/Met signaling by valproic acid

Yohsuke Matsumoto, Takahiro Motoki, Satoshi Kubota, Masaharu Takigawa, Hirohito Tsubouchi, Eiichi Gohda

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 366 ( 1 ) 110 - 116 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Hepatocyte growth factor (HGF), which is produced by surrounding stromal cells, including fibroblasts and endothelial cells, has been shown to be a significant factor responsible for cancer cell invasion mediated by tumor-stromal interactions. We found in this study that the anti-tumor agent valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, strongly inhibited tumor-stromal interaction. VPA inhibited HGF production in fibroblasts induced by epidermal growth factor (EGF), platelet-derived growth factor, basic fibroblast growth factor, phorbol 12-myristate 13-acetate (PMA) and prostaglandin E-2 without any appreciable cytotoxic effect. Other HDAC inhibitors, including butyric acid and trichostatin A (TSA), showed similar inhibitory effects on HGF production stimulated by various inducers. Up-regulations of HGF gene expression induced by PMA and EGF were also suppressed by VPA and TSA. Furthermore, VPA significantly inhibited HGF-induced invasion of HepG2 hepatocellular carcinoma cells. VPA, however, did not affect the increases in phosphorylation of MAPK and Akt in HGF-treated HepG2 cells. These results demonstrated that VPA inhibited two critical processes of tumor-stromal interaction, induction of fibroblastic HGF production and HGF-induced invasion of HepG2 cells, and suggest that those activities serve for other anti-tumor mechanisms of VPA besides causing proliferation arrest, differentiation, and/or apoptosis of tumor cells. (C) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2007.11.089

Effects of tensile and compressive strains on response of a chondrocytic cell line embedded in type I collagen gel

Yuji Hirano, Naoki Ishiguro, Masahiro Sokabe, Masaharu Takigawa, Keiji Naruse

JOURNAL OF BIOTECHNOLOGY 133 ( 2 ) 245 - 252 2008.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Tensile and compressive strains are commonly used in mechanobiological models. Here we report on the development of a novel three-dimensional cell-culture method, which allows both tensile and compressive loads to be applied. Preliminary results were obtained using HCS2/8 chondrocytic cells embedded in type I collagen gel. This construct was subjected to either 16% tension or 14% compression. Confocal laser scanning microscopy showed that both tension and compression caused significant cell deformation. The collagen gel-embedded HCS2/8 cells were subjected to static tension, dynamic tension, static compression or dynamic compression for 24 h. Dynamic compression led to significantly decreased 5-bromo-2'-deoxyuridine incorporation compared with the control group. PCR analysis revealed upregulation of type II collagen caused by dynamic tension, upregulation of aggrecan caused by static compression, and downregulation of type II collagen and aggrecan caused by dynamic compression. Nitric oxide production was significantly increased by static tension and static compression compared with the control group. Our experimental system effectively applied several types of strain to HCS2/8 cells embedded in collagen gel. Our results suggest that the mode of mechanical strain affects the response of HCS2/8 cells. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jbiotee.2007.07.955

Role of mechanical-stress inducible protein Hcs24/CTGF/CCN2 in cartilage growth and regeneration: Mechanical stress induces expression of Hcs24/CTGF/CCN2 in a human chondrocytic cell line HCS-2/8, rabbit costal chondrocytes and meniscus tissue cells

Takashi Nishida, Azusa Maeda, Satoshi Kubota, Masaharu Takigawa

BIORHEOLOGY 45 ( 3-4 ) 289 - 299 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：IOS PRESS

Mechanical stress plays an important role in the cartilage metabolism. The aim of this study is to determine the influence of mechanical load magnitude and frequency on cartilage metabolism in terms of the expression of hypertrophic chondrocyte-specific gene product 24/connective tissue growth factor/CCN family 2 (Hcs24/CTGF/CCN2), as an essential mediator of extracellular matrix (ECM) production. When a human chondrocytic cell line, HCS-2/8 was exposed to uni-axial cyclic mechanical force (6% elongation, 10 times/min) only for 30 min, the expression level of Hcs24/CTGF/CCN2 (CCN2) increased, and c-Jun N-terminal protein kinase (JNK) was activated. These findings suggest that stretch-induced CCN2 may be mediated by the JNK pathway. When HCS-2/8 cells were subjected to cyclic tension force at 15 kPa, 30 cycles/min, which has been reported to be a degradation force for HCS-2/8 cells, the expressions of CCN2 and aggrecan were inhibited, and such expressions remained unchanged in rabbit hyaline costal cartilage cells. However, these expressions increased in rabbit meniscus tissue cells. These findings suggest that the sensitivity of mechanical stretch may be different depending on the type of cells. Furthermore, CCN2 was co-localized with aggrecan in this meniscus tissue region exposed to mechanical stress in vivo. These findings suggest that CCN2 induced by mechanical stress may therefore play some role in meniscus growth and regeneration.

DOI： 10.3233/BIR-2008-0478

Promotion of hydroxyapatite-associated, stem cell-based bone regeneration by CCN2

Mitsuaki Ono, Satoshi Kubota, Takuo Fujisawa, Wataru Sonoyama, Harumi Kawakij, Kentaro Akiyama, Kengo Shimono, Masarnitsu Oshima, Takashi Nishida, Yasuhiro Yoshida, Kazuomi Suzuki, Masaharu Takigawa, Takuo Kuboki

CELL TRANSPLANTATION 17 ( 1-2 ) 231 - 240 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：COGNIZANT COMMUNICATION CORP

Multiple roles have been already recognized for CCN2 in cartilage development and regeneration. However, the effects of CCN2 on bone regeneration remain to be elucidated. In this study, the utility of CCN2 on bone regeneration was examined in vitro and in vivo in combination with hydroxyapatite (HAp) as a scaffold. Human bone marrow stromal cells (hBMSCs) were isolated from human iliac bone marrow aspirates of healthy donors and expanded, and the effects of CCN2 on their proliferation and migration were examined in vitro. The proliferation of hBMSCs on a plastic or HAp plate was significantly enhanced by CCN2. Moreover, the migration of hBMSCs also dramatically increased by CCN2. Interestingly, a C-terminal signal modular fragment of CCN2 (CT-module) also enhanced the cell proliferation and migration as efficiently as the full-length CCN2. Next, in order to estimate the effect of CCN2 on the migration and survival of hBMSCs and bone formation inside the HAp scaffold in vivo, two experiments were performed. First, the porous HAp carrier was cultured with hBMSCs for a week, and the cell-scaffold hybrid was transplanted with or without CCN2 subcutaneously into immunocompromised mice. CCN2 accelerated the hBMSC-like cell migration and survival inside the porous HAp within 4 weeks after transplantation. Second, the porous HAp carrier with or without CCN2 was directly implanted into bone defects within a rabbit mandible, and bone regeneration inside was evaluated. As a result, CCN2 efficiently induced the cell invasion and bone formation inside the porous HAp scaffold. These findings suggest that CCN2 and its CT-module fragment could be useful for regeneration and reconstruction of large-scale bone defects.

DOI： 10.3727/000000008783907143

Gene expression and distribution of connective tissue growth factor (CCN2/CTGF) during secondary ossification center formation

Morihiko Oka, Satoshi Kubota, Seiji Kondo, Takanori Eguchi, Chisa Kuroda, Kazumi Kawata, Shogo Minagi, Masaharu Takigawa

JOURNAL OF HISTOCHEMISTRY & CYTOCHEMISTRY 55 ( 12 ) 1245 - 1255 2007.12

Language：English Publishing type：Research paper (scientific journal) Publisher：HISTOCHEMICAL SOC INC

CCN2/connective tissue growth factor (CCN2/CTGF) is a critical signaling modulator of mesenchymal tissue development. This study investigated the localization and expression of CCN2/CTGF as a factor supporting angiogenesis and chondrogenesis during development of secondary ossification centers in the mouse tibial epiphysis. Formation of the secondary ossification center was initiated by cartilage canal formation and blood vessel invasion at 7 days of age, and onset of ossification was observed at 14 days. In situ hybridization showed that CCN2/CTGF mRNA was distinctively expressed in the region of the cartilage canal and capsule-attached marginal tissues at 7 days of age, and distinct expression was also observed in proliferating chondrocytes around the marrow space at 14 days of age. Immunostaining showed that CCN2/CTGF was distributed broadly around the expressed cells located in the central region of the epiphysis, where the chondrocytes become hypertrophic and the cartilage canal enters into the hypertrophic mass. Furthermore, an overlapping distribution of metal loproteinase (MMP)9 and CCN2/CTGF was found in the secondary ossification center. These findings suggest that the CCN2/CTGF is involved in establishing epiphyseal vascularization and remodeling, which eventually determines the secondary ossification center in the developing epiphysial cartilage.

DOI： 10.1369/jhc.7A7263.2007

Proteasome inhibition up-regulates p53 and apoptosis-inducing factor in chondrocytes causing severe growth retardation in mice

Farasat Zaman, Victoria Menendez-Benito, Emma Eriksson, Andrei S. Chagin, Masaharu Takigawa, Bengt Fadeel, Nico P. Dantuma, Dionisios Chrysis, Lars Saevendahl

CANCER RESEARCH 67 ( 20 ) 10078 - 10086 2007.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

Proteasome inhibitors (PI), a novel class of anticancer drugs, are relatively well tolerated and have recently been introduced into the clinic for the treatment of multiple myeloma. The tumor selectivity and low toxicity of PIs are surprising, given the crucial role of the ubiquitin/proteasome system in a multitude of cellular processes. Here, we show that systemic administration of PIs specifically impairs the ubiquitin/ proteasome system in growth plate chondrocytes. Importantly, young mice displayed severe growth retardation during treatment as well as 45 days after the cessation of treatment with clinically relevant amounts of MG262 (0.2 [mu mol/kg body weight/injection) or bortezomib (1.0 mg/kg body weight/ injection). Dysfunction of the ubiquitin/proteasome system was accompanied by the induction of apoptosis of stem-like and proliferative chondrocytes in the growth plate. These results were recapitulated in cultured fetal rat metatarsal bones and chondrocytic cell lines (rat, human). Apoptosis was associated with up-regulation of the proapoptotic molecules, p53 and apoptosis-inducing factor (AIF), both in vitro and in vivo. In addition to the observation that AIF is expressed in the growth plate, we also provide evidence that AIF serves as a direct target protein for ubiquitin, thus explaining its prominent up-regulation upon proteasome inhibition. Suppression of p53 or AIF expression with small interfering RNAs partly rescued chondrocytes from proteasome inhibition-induced apoptosis (35% and 41%, respectively). Our observations show that proteasome inhibition may selectively target essential cell populations in the growth plate causing significant growth failure. These findings could have important implications for the use of proteasome inhibitors in the treatment of childhood cancer. [Cancer Res 2007;67(20):10078-86]

DOI： 10.1158/0008-5472.CAN-06-3982

CCN2 (Connective Tissue Growth Factor) is essential for extracellular matrix production and integrin signaling in chondrocytes

Takashi Nishida, Harumi Kawaki, Ruth M. Baxter, R. Andrea DeYoung, Masaharu Takigawa, Karen M. Lyons

JOURNAL OF CELL COMMUNICATION AND SIGNALING 1 ( 1 ) 45 - 58 2007.6

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The matricellular protein CCN2 (Connective Tissue Growth Factor; CTGF) is an essential mediator of ECM composition, as revealed through analysis of Ccn2 deficient mice. These die at birth due to complications arising from impaired endochondral ossification. However, the mechanism(s) by which CCN2 mediates its effects in cartilage are unclear. We investigated these mechanisms using Ccn2(-/-) chondrocytes. Expression of type II collagen and aggrecan were decreased in Ccn2(-/-) chondrocytes, confirming a defect in ECM production. Ccn2(-/-) chondrocytes also exhibited impaired DNA synthesis and reduced adhesion to fibronectin. This latter defect is associated with decreased expression of alpha 5 integrin. Moreover, CCN2 can bind to integrin alpha 5 beta 1 in chondrocytes and can stimulate increased expression of integrin alpha 5. Consistent with an essential role for CCN2 as a ligand for integrins, immuno-fluorescence and Western blot analysis revealed that levels of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK)1/2 phosphorylation were reduced in Ccn2(-/-) chondrocytes. These findings argue that CCN2 exerts major effects in chondrocytes through its ability to (1) regulate ECM production and integrin alpha 5 expression, (2) engage integrins and (3) activate integrin-mediated signaling pathways.

DOI： 10.1007/s12079-007-0005-z

Report on the fourth international workshop on the CCN family of genes

S. Kubota, H. Yeger, B. Perbal, M. Takigawa

JOURNAL OF CELL COMMUNICATION AND SIGNALING 1 ( 1 ) 59 - 65 2007.6

Tamoxifen induces permanent growth arrest through selective induction of apoptosis in growth plate chondrocytes in cultured rat metatarsal bones

Andrei S. Chagin, Elham Karimian, Farasat Zaman, Masaharu Takigawa, Dionisios Chrysis, Lars Savendahl

BONE 40 ( 5 ) 1415 - 1424 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Estrogen affects skeletal growth and promotes growth plate fusion in humans. High doses of estrogen have been used to limit growth in girls with predicted extreme tall stature; a treatment which has been associated with severe side effects. Selective estrogen receptor modulators (SERMs) could potentially be used as an alternative treatment. We chose to study the effects of Tamoxifen (Tam), a first generation SERM that has been used in the treatment of pubertal gynecomastia or McCune-Albright syndrome.
Cultured fetal rat metatarsal bones were used to study the effects of Tam on longitudinal bone growth. In sectioned bones, chondrocyte apoptosis and proliferation were analyzed by TUNEL assay and BrdU incorporation, respectively. We also used a human chondrocytic cell line, HSC-2/8, to study the effects of Tam on apoptosis (FACS analysis and Cell Death detection ELISA) and caspase activation (caspase substrate cleavage and Western immunoblotting).
Tam caused a dose-dependent growth retardation of cultured metatarsal bones. No catch-up growth was observed after Tam was removed from the culture medium. Detailed analysis of sectioned growth plate cartilage revealed increased apoptosis of chondrocytes within the resting and hypertrophic zones. HCS-2/8 cells also underwent apoptosis upon Tam treatment. Tam-induced apoptosis was caspase-dependent and completely abrogated by either caspase-8 or -9 inhibitors. A substrate assay revealed that caspase-8 is first activated followed by caspase-9 and -3. Finally, FasL secretion was stimulated by Tam and blocking of either FasL or Fas decreased Tam-induced apoptosis in chondrocytes.
We here describe a novel mechanism of tamoxifen-induced apoptosis in chondrocytes, involving the activation of caspases and the FasL/Fas pathway, which diminishes the potential for bone growth. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2006.12.066

Promotion of attachment of human bone marrow stromal cells by CCN2

Mitsuaki Ono, Satoshi Kubota, Takuo Fujisawa, Wataru Sonoyama, Harumi Kawaki, Kentaro Akiyama, Masamitsu Oshima, Takashi Nishida, Yasuhlro Yoshida, Kazuomi Suzuki, Masaharu Takigawa, Takuo Kuboki

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 357 ( 1 ) 20 - 25 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Cell attachment is a crucial step in tissue regeneration. In this study, human bone marrow stromal cells (hBMSCs) were isolated, and the effects of CCN2 on their attachment were examined. CCN2 significantly enhanced the hBMSC attachment, and this enhanced cell attachment was mainly regulated by the C-terminal module of CCN2. This enhancement was negated by the anti-integrin alpha(v)beta(3) antibody and p38 MAPK inhibitor, and phosphorylation of p38 MAPK was detected upon the enhanced cell attachment mediated by CCN2. We thus conclude that CCN2 enhances hBMSC attachment via integrin-p38 MAPK signal pathway. Enhanced hBMSC attachment on hydroxyapatite plates by CCN2 further indicated the utility of CCN2 in bone regeneration. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2007.03.052

Increased connective tissue growth factor relative to brain natriuretic peptide as a determinant of myocardial fibrosis

Norimichi Koitabashi, Masashi Arai, Shinya Kogure, Kazuo Niwano, Atai Watanabe, Yasuhiro Aoki, Toshitaka Maeno, Takashi Nishida, Satoshi Kubota, Masaharu Takigawa, Masahiko Kurabayashi

HYPERTENSION 49 ( 5 ) 1120 - 1127 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Excessive fibrosis contributes to an increase in left ventricular stiffness. The goal of the present study was to investigate the role of connective tissue growth factor (CCN2/CTGF), a profibrotic cytokine of the CCN (Cyr61, CTGF, and Nov) family, and its functional interactions with brain natriuretic peptide (BNP), an antifibrotic peptide, in the development of myocardial fibrosis and diastolic heart failure. Histological examination on endomyocardial biopsy samples from patients without systolic dysfunction revealed that the abundance of CTGF-immunopositive cardiac myocytes was correlated with the excessive interstitial fibrosis and a clinical history of acute pulmonary congestion. In a rat pressure overload cardiac hypertrophy model, CTGF mRNA levels and BNP mRNA were increased in proportion to one another in the myocardium. Interestingly, relative abundance of mRNA for CTGF compared with BNP was positively correlated with diastolic dysfunction, myocardial fibrosis area, and procollagen type 1 mRNA expression. Investigation with conditioned medium and subsequent neutralization experiments using primary cultured cells demonstrated that CTGF secreted by cardiac myocytes induced collagen production in cardiac fibroblasts. Further, G protein - coupled receptor ligands induced expression of the CTGF and BNP genes in cardiac myocytes, whereas aldosterone and transforming growth factor-beta preferentially induced expression of the CTGF gene. Finally, exogenous BNP prevented the production of CTGF in cardiac myocytes. These data suggest that a disproportionate increase in CTGF relative to BNP in cardiac myocytes plays a central role in the induction of excessive myocardial fibrosis and diastolic heart failure.

DOI： 10.1161/HYPERTENSIONAHA.106.077537

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