Faculty Profiles - EGUCHI Takanori

マイクロRNA 18aによるCcn2/Ctgf遺伝子を介した軟骨細胞分化の制御機構の解明

大河原敏博, 久保田聡, 川木晴美, 近藤誠二, 江口傑徳, 佐々木朗, 滝川正春

日本骨代謝学会学術集会プログラム抄録集 26回 168 - 168 2008.10

軟骨細胞成熟における低密度リポ蛋白受容体関連タンパク-1(LRP1)の関与

河田かずみ, 河田かずみ, 久保田聡, 江口傑徳, 青山絵理子, 皆木省吾, 滝川正春

日本軟骨代謝学会プログラム・抄録集 21st 2008

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

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

The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society 55 ( 12 ) 1245 - 55 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 metalloproteinase (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

Different transcriptional strategies for ccn2/ctgf gene induction between human chondrocytic and breast cancer cell lines. Reviewed International journal

Takanori Eguchi, Satoshi Kubota, Kazumi Kawata, Yoshiki Mukudai, Toshihiro Ohgawara, Kohei Miyazono, Kyouji Nakao, Seiji Kondo, Masaharu Takigawa

Biochimie 89 ( 3 ) 278 - 88 2007.3

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Connective tissue growth factor (CTGF/CCN2) plays a critical role in endochondral bone formation; however, CCN2 also promotes angiogenesis and bone metastasis in breast cancer. Chondrocytic HCS-2/8 cells and breast cancer MDA231 cells produce over 6 times more CCN2 than any other cell type. In this study, we demonstrate that these cell lines employ different transcriptional strategies for ccn2 gene induction. Four tandem copies of the dominant transcriptional enhancer in chondrocytes (4 x TRENDIC) were chimerically connected to an SV40 promoter-luciferase construct and subsequently analyzed. The enhancement of the promoter activity by 4 x TRENDIC was greater in the HCS-2/8 cells (7-fold) than in the other 4 cell lines (3-4 fold). The TRENDIC-binding protein complex was detected at a higher signal in the HCS-2/8 cells than in the other cell lines. In addition, the HCS-2/8 nuclear factors strongly targeted not only TRENDIC, but also the previously reported basal control element and a novel enhancer element in the ccn2 promoter. In contrast, high-level ccn2 gene induction in MDA231 cells was largely dependent on Smad signaling through the Smad-binding element in the ccn2 promoter. Based on these results, we propose a model of differential transcription of the ccn2 gene between the chondrocytic cell line and the breast cancer cell line, and therefore imply that these cells utilize distinct transcriptional strategies to obtain the enhanced CCN2 production that is not observed in other types of cells.

DOI： 10.1016/j.biochi.2006.12.006

Pathogenic role of connective tissue growth factor (CTGF/CCN2) in osteolytic metastasis of breast cancer. Reviewed International journal

Tsuyoshi Shimo, Satoshi Kubota, Norie Yoshioka, Soichiro Ibaragi, Sachiko Isowa, Takanori Eguchi, Akira Sasaki, Masaharu Takigawa

Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 21 ( 7 ) 1045 - 59 2006.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BONE & MINERAL RES

UNLABELLED: The role of CTGF/CCN2 in osteolytic metastasis by breast cancer cells and its mechanism of action were studied. Osteolytic metastasis accompanied by CCN2 and PTHrP overproduction was efficiently inhibited by an anti-CCN2 antibody. Furthermore, we found that CCN2 was induced by PTHrP through PKA-, PKC-, and ERK-mediated pathways therein. INTRODUCTION: Connective tissue growth factor (CTGF/CCN2) is a mediator of local angiogenesis induced by breast cancer, but its role in osteolytic metastasis has not been evaluated. PTH-related peptide (PTHrP) is another critical factor in the development of the osteolytic metastasis. Using both in vivo and in vitro approaches, we studied whether/how neutralization of CCN2 prevented bone metastasis and how PTHrP signaling is related. MATERIALS AND METHODS: A mouse model of bone metastasis by human breast cancer cell line MDA231 was treated with a CCN2-neutralizing antibody, and osteolytic bone metastases were assessed on radiographs and immunohistochemistry. Ccn2 gene expression and transcription were examined by Northern blot and luciferase analysis. Immunoblot analysis and kinase inhibitors were used to identify the signaling pathways implicated. Anti-angiogenic/osteoclastogenic effects of ccn2 downregulation were also evaluated. RESULTS: Treatment of mice with a CCN2-neutralizing antibody greatly decreased osteolytic bone metastasis, microvasculature, and osteoclasts involved. The antibody also suppressed the growth of subcutaneous tumor in vivo and proliferation and migration of human umbilical vein endothelial cells (HUVECs) in vitro. Downregulation of ccn2 also repressed osteoclastogenesis. CCN2 expression was specifically observed in cancer cells producing PTHrP and type I PTH/PTHrP receptor (PTH1R) invaded the bone marrow, and PTHrP strongly upregulated ccn2 in MDA231 cells in vitro. Activation of protein kinase C (PKC) and protein kinase A (PKA) was necessary and sufficient for the stimulation of ccn2 by PTHrP. Indeed, inhibition of the extracellular signal-regulated kinase (ERK1/2), PKC, or PKA by specific inhibitors counteracted the stimulation of ccn2 expression. Incubation of MDA231 cells with PTHrP induced the activation of ERK1/2. Consistent with these findings, inhibition of PKC prevented PTHrP-induced ERK1/2 activation, whereas 12-O-tetradecanoylphorbol13-acetate (TPA), a stimulator of PKC, upregulated it. CONCLUSIONS: CCN2 was critically involved in osteolytic metastasis and was induced by PKA- and PKC-dependent activation of ERK1/2 signaling by PTHrP. Thus, CCN2 may be a new molecular target for anti-osteolytic therapy to shut off the PTHrP-CCN2 signaling pathway.

DOI： 10.1359/JBMR.060416

Possible role of LRP1, a CCN2 receptor, in chondrocytes. Reviewed International journal

Kazumi Kawata, Takanori Eguchi, Satoshi Kubota, Harumi Kawaki, Morihiko Oka, Shogo Minagi, Masaharu Takigawa

Biochemical and biophysical research communications 345 ( 2 ) 552 - 9 2006.6

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

Low density lipoprotein receptor (LDLR)-related protein 1 (LRP1/CD91) is one of the receptors of CCN2 that conducts endochondral ossification and cartilage repair. LRP1 is a well-known endocytic receptor, but its distribution among chondrocytes remains to be elucidated. We herein demonstrate for the first time that the distribution of LRP1 in chondrocytes except for hypertrophic chondrocytes in vivo and in vitro. Interestingly, the LRP1 levels were higher in mature chondrocytic HCS-2/8 and osteoblastic SaOS-2 than in other cells, whereas the other LDLR family members involved in ossification were detected at lower levels in HCS-2/8. It was interesting to note that in HCS-2/8, LRP1 was observed not only on the cell surface and in the cytoplasm, but also in the nucleus. Exogenously added CCN2 was incorporated into HCS-2/8, which was partially co-localized with LRP1, and targeted to the recycling endosomes and nucleus as well as the lysosomes. These findings suggest specific roles of LRP1 in cartilage biology.

DOI： 10.1016/j.bbrc.2006.04.109

二次骨化中心形成過程に発現する結合組織成長因子CTGF/CCN2のパールカン陽性軟骨細胞への特異的集積

岡森彦, 久保田聡, 近藤誠二, 江口傑徳, 河田かずみ, 黒田知沙, 皆木省吾, 滝川正春

日本骨代謝学会学術集会プログラム抄録集 23回 229 - 229 2005.6

Collaborative action of M-CSF and CTGF/CCN2 in articular chondrocytes: possible regenerative roles in articular cartilage metabolism. Reviewed International journal

Kyouji Nakao, Satoshi Kubota, Hideyuki Doi, Takanori Eguchi, Morihiko Oka, Takuo Fujisawa, Takashi Nishida, Masaharu Takigawa

Bone 36 ( 5 ) 884 - 92 2005.5

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

It is known that expression of the macrophage colony-stimulating factor (M-CSF) gene is induced in articular chondrocytes upon inflammation. However, the functional role of M-CSF in cartilage has been unclear. In this study, we describe possible roles of M-CSF in the protection and maintenance of the articular cartilage based on the results of experiments using human chondrocytic cells and rat primary chondrocytes. Connective tissue growth factor (CTGF/CCN2) is known to be a potent molecule to regenerate damaged cartilage by promoting the growth and differentiation of articular chondrocytes. Here, we uncovered the fact that M-CSF induced the mRNA expression of the ctgf/ccn2 gene in those cells. Enhanced production of CTGF/CCN2 protein by M-CSF was also confirmed. Furthermore, M-CSF could autoactivate the m-csf gene, forming a positive feed-back network to amplify and prolong the observed effects. Finally, promotion of proteoglycan synthesis was observed by the addition of M-CSF. These findings taken together indicate novel roles of M-CSF in articular cartilage metabolism in collaboration with CTGF/CCN2, particularly during an inflammatory response. Such roles of M-CSF were further supported by the distribution of M-CSF producing chondrocytes in experimentally induced rat osteoarthritis cartilage in vivo.

DOI： 10.1016/j.bone.2004.10.015

Regulation of chicken ccn2 gene by interaction between RNA cis-element and putative trans-factor during differentiation of chondrocytes. Reviewed International journal

Yoshiki Mukudai, Satoshi Kubota, Takanori Eguchi, Seiji Kondo, Kyouji Nakao, Masaharu Takigawa

The Journal of biological chemistry 280 ( 5 ) 3166 - 77 2005.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

CCN2/CTGF is a multifunctional growth factor. Our previous studies have revealed that CCN2 plays important roles in both growth and differentiation of chondrocytes and that the 3'-untranslated region (3'-UTR) of ccn2 mRNA contains a cis-repressive element of gene expression. In the present study, we found that the stability of chicken ccn2 mRNA is regulated in a differentiation stage-dependent manner in chondrocytes. We also found that stimulation by bone morphogenetic protein 2, platelet-derived growth factor, and CCN2 stabilized ccn2 mRNA in proliferating chondrocytes but that it destabilized the mRNA in prehypertrophic-hypertrophic chondrocytes. The results of a reporter gene assay revealed that the minimal repressive cis-element of the 3'-UTR of chicken ccn2 mRNA was located within the area between 100 and 150 bases from the polyadenylation tail. Moreover, the stability of ccn2 mRNA was correlated with the interaction between this cis-element and a putative 40-kDa trans-factor in nuclei and cytoplasm. In fact, the binding between them was prominent in proliferating chondrocytes and attenuated in (pre)hypertrophic chondrocytes. Stimulation by the growth factors repressed the binding in proliferating chondrocytes; however, it enhanced it in (pre)hypertrophic chondrocytes. Therefore, gene expression of ccn2 mRNA during endochondral ossification is properly regulated, at least in part, by changing the stability of the mRNA, which arises from the interaction between the RNA cis-element and putative trans-factor.

DOI： 10.1074/jbc.M411632200

Interaction of AP-1 and the ctgf gene: a possible driver of chondrocyte hypertrophy in growth cartilage. Reviewed

Norifumi H Moritani, Satoshi Kubota, Takanori Eguchi, Tomohiro Fukunaga, Takashi Yamashiro, Teruko Takano-Yamamoto, Hideki Tahara, Kazumi Ohyama, Toshio Sugahara, Masaharu Takigawa

Journal of bone and mineral metabolism 21 ( 4 ) 205 - 10 2003

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

The expression of the connective tissue growth factor ( ctgf) gene increases along with the differentiation of growth cartilage cells, and the highest expression is observed in the hypertrophic stage. Similarly, recent reports demonstrated c- fos expression in chondrocytes in the early hypertrophic zone of growth cartilage, and suggested that the c- fos gene may play a crucial role in the regulation of hypertrophic differentiation. A chondrocytic human cell line, HCS-2/8, is known to retain a variety of chondrocytic phenotypes. When such cells were kept overconfluent, they expressed increasing levels of c- fos transcripts along a time course phenotypically similar to that of hypertrophic differentiation. Moreover, by using a competitive electromobility-shift assay, we found that AP-1, a Fos/Jun heterodimer, in HCS-2/8 was capable of binding not only to a typical AP-1-binding DNA fragment but also to the enhancer fragment of the ctgf gene. Based on the findings above, we hypothesize that, prior to hypertrophic differentiation, AP-1-related oncogenes are activated and that their gene products subsequently activate ctgf gene expression, which might eventually induce hypertrophy.

DOI： 10.1007/s00774-003-0410-1

軟骨由来成長因子CTGF/Hcs24の細胞種特異的遺伝子発現抑制機構の解析

森谷徳文, 久保田聡, 江口傑徳, 近藤誠二, 菅原利夫, 滝川正春

生化学 74 ( 8 ) 913 - 913 2002.8

A novel cis-element that enhances connective tissue growth factor gene expression in chondrocytic cells. Reviewed International journal

Takanori Eguchi, Satoshi Kubota, Seiji Kondo, Takuo Kuboki, Hirofumi Yatani, Masaharu Takigawa

Biochemical and biophysical research communications 295 ( 2 ) 445 - 51 2002.7

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

To clarify the chondrocyte-specific regulatory mechanism of connective tissue growth factor (ctgf) gene expression, we analyzed the functionality and DNA-protein interaction of the CTGF promoter. Comparative luciferase assay of the CTGF promoter deletion mutants among HCS-2/8 chondrocytic cells and fibroblastic cells revealed that a 110-bp region in the promoter was crucial for the HCS-2/8-specific transcriptional enhancement. Subsequent competitive gel shift assay revealed that transcription factors in HCS-2/8 nuclei bound to a 60-bp portion in the corresponding region. Relative luciferase activity from a CTGF promoter with mutant TGF-beta response element (TbRE) was 16.9% lower than that from an intact promoter. On the other hand, relative luciferase activity from a CTGF promoter with 4bp point mutations at 30bp upstream of the TbRE was 47.7% lower than that from the intact one. The binding activity of HCS-2/8 nuclear factor(s) to the sequence over the 4-bp was remarkably higher than that of any nuclear extract from other types of cells. Therefore, we entitled the sequence 'TRENDIC', a transcription enhancer dominant in chondrocytes, which stands for a novel enhancer for chondrocyte-specific CTGF gene expression.

DOI： 10.1016/S0006-291X(02)00700-3

Connective tissue growth factor increased by hypoxia may initiate angiogenesis in collaboration with matrix metalloproteinases. Reviewed International journal

Seiji Kondo, Satoshi Kubota, Tsuyoshi Shimo, Takashi Nishida, Gen Yosimichi, Takanori Eguchi, Toshio Sugahara, Masaharu Takigawa

Carcinogenesis 23 ( 5 ) 769 - 76 2002.5

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

Connective tissue growth factor (CTGF) is known to be a potent angiogenic factor. Here we investigated how CTGF and matrix metalloproteinases (MMPs) are involved in the early stage of hypoxia-induced angiogenesis using human breast cancer cell line, MDA231, and vascular endothelial cells. Hypoxic stimulation (5% O(2)) of MDA231 cells increased their steady-state level of ctgf mRNA by approximately 2-fold within 1.5 h, and the levels remained at a plateau up to 6 h, and then decreased by 12 h as compared with the cells cultured under the normoxic condition. Membrane-type 1 MMP (MT1-MMP) mRNA levels was also increased within a few hours of the exposure to hypoxia. Indeed, ELISA revealed that the CTGF protein/cell in medium conditioned by MDA231 cells exposed to hypoxia was maximally greater at 24 h than in the medium from normoxic cultures and that the secretion rate (supernatant CTGF/cell layer CTGF) increased in a time-dependent manner from 24 to 72 h of hypoxic exposure. Hypoxic induction of CTGF was also confirmed by immunohistochemical analyses. Furthermore, zymogram analysis revealed that the production of active MMP-9 was also induced in MDA231 cells incubated under hypoxic conditions. Finally, we found that recombinant CTGF also increased the expression of a number of metalloproteinases that play a role in the vascular invasive processes and decreased the expression of tissue inhibitors of metalloproteinases by vascular endothelial cells. These findings suggest that hypoxia stimulates MDA231 cells to release CTGF as an angiogenic modulator, which initiates the invasive angiogenesis cascade by modulating the balance of extracellular matrix synthesis and degradation via MMPs secreted by endothelial cells in response to CTGF. This cascade may play critical roles in the hypoxia-induced neovascularization that accompanies tumor invasion in vivo.