研究者詳細 - 久保田　聡

論文 - 久保田　聡

分割表示 229 件中 141 - 160 件目／全件表示 >>

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年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

Expression and physiological role of CCN4/Wnt-induced secreted protein 1 mRNA splicing variants in chondrocytes

Takeshi Yanagita, Satoshi Kubota, Harumi Kawaki, Kazumi Kawata, Seiji Kondo, Teruko Takano-Yamamoto, Shinji Tanaka, Masaharu Takigawa

FEBS JOURNAL 274 ( 7 ) 1655 - 1665 2007年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

CCN4/Wnt-induced secreted protein 1 (WISP1) is one of the CCN (CTGF/Cyr61/Nov) family proteins. CCN members have typical structures composed of four conserved cysteine-rich modules and their variants lacking certain modules, generated by alternative splicing or gene mutations, have been described in various pathological conditions. Several previous reports described a CCN4/WISP1 variant (WISP1v) lacking the second module in a few malignancies, but no information concerning the production of WISP1 variants in normal tissue is currently available. The expression of CCN4/WISP1 mRNA and its variants were analyzed in a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8, and primary rabbit growth cartilage (RGC) chondrocytes. First, we found WISP1v and a novel variant of WISP1 (WISP1vx) to be expressed in HCS-2/8, as well as full-length WISP1 mRNA. This new variant was lacking the coding regions for the second and third modules and a small part of the first module. To monitor the expression of CCN4/WISP1 mRNA along chondrocyte differentiation, RGC cells were cultured and sampled until they were mineralized. As a result, we identified a WISP1v ortholog in normal RGC cells. Interestingly, the WISP1v mRNA level increased dramatically along with terminal differentiation. Furthermore, overexpression of WISP1v provoked expression of an alkaline phosphatase gene that is a marker of terminal differentiation in HCS-2/8 cells. These findings indicate that WISP1v thus plays a critical role in chondrocyte differentiation toward endochondral ossification, whereas HCS-2/8-specific WISP1vx may be associated with the transformed phenotypes of chondrosarcomas.

DOI： 10.1111/j.1742-4658.2007.05709.x

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

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

BIOCHIMIE 89 ( 3 ) 278 - 288 2007年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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 pro-moter-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. (c) 2007 Elsevier Masson SAS. All rights reserved.

DOI： 10.1016/j.biochi.2006.12.006

CCN family proteins and angiogenesis: From embryo to adulthood

Satoshi Kubota, Masaharu Takigawa

Angiogenesis 10 ( 1 ) 1 - 11 2007年3月

記述言語：英語

The CCN family is a novel class of extracellular signal modulators that has been recently established. Typical members are composed of four conserved modules connected tandem, each of which is rich in cysteines and highly interactive with other molecules. The mammalian CCN family consists of six members, most of which have been described as multifunctional factors for the developmental process of mesenchymal tissue including blood vessel formation/induction. Particularly, the angiogenic properties of the three classical members, CCN1, 2 and 3 have so far been characterized, and their physiological and pathological significance has thus been indicated. Recent research has uncovered a unique mechanism regarding these proteins in promoting and/or modulating developmental, physiological and pathological angiogenic events. Namely, CCN proteins exert their ability to drive angiogenesis, not by stimulating a particular behavior of a particular type of cells, but by manipulating the cell communication networks that integrate most of the associated molecules/cells toward angiogenesis. In this article, the role of the CCN proteins in a variety of angiogenic events as an organizer of microenvironmental cell society is comprehensively described, together with a brief summary of the recent findings on each CCN family member relevant to angiogenesis including cardiovascular development and diseases. © 2006 Springer Science + Business Media B.V.

DOI： 10.1007/s10456-006-9058-5

結合組織増殖因子CTGF/CCN2

服部高子, 久保田聡, 滝川正春

The Lung 15 331 - 335 2007年

Role of CCN2/CTGF/Hcs24 in bone growth 査読

Satoshi Kubota, Masaharu Takigawa

INTERNATIONAL REVIEW OF CYTOLOGY - A SURVEY OF CELL BIOLOGY, VOL 257 257 1 - 41 2007年

記述言語：英語掲載種別：論文集(書籍)内論文出版者・発行元：ELSEVIER ACADEMIC PRESS INC

Our bones mostly develop through a process called endochondral ossification. This process is initiated in the cartilage prototype of each bone and continues through embryonic and postnatal development until the end of skeletal growth. Therefore, the central regulator of endochondral ossification is the director of body construction, which is, in other words, the determinant of skeletal size and shape. We suggest that CCN2/CTGF/Hcs24 (CCN2) is a molecule that conducts all of the procedures of endochondral ossification. CCN2, a member of the CCN family of novel modulator proteins, displays multiple functions by manipulating the local information network, using its conserved modules as an interface with a variety of other biomolecules. Under a precisely designed four-dimensional genetic program, 002 is produced from a limited population of chondrocytes and acts on all of the mesenchymal cells inside the bone callus to promote the integrated growth of the bone. Furthermore, the utility of CCN2 as regenerative therapeutics against connective tissue disorders, such as bone and cartilage defects and osteoarthritis, has been suggested. Over the years, the pathological action of CCN2 has been suggested. Nevertheless, it can also be regarded as another aspect of the physiological and regenerative function of CCN2, which is discussed as well.

DOI： 10.1016/S0074-7696(07)57001-4

Multiple activation of mitogen-activated protein kinases by purified independent CCN2 modules in vascular endothelial cells and chondrocytes in culture

S. Kubota, H. Kawaki, S. Kondo, G. Yosimichi, M. Minato, T. Nishida, H. Hanagata, A. Miyauchi, M. Takigawa

BIOCHIMIE 88 ( 12 ) 1973 - 1981 2006年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

CCN2 consists of 4 distinct modules that are conserved among various CCN family protein members. From the N-terminus, insulin-like growth factor binding protein (IGFBP), von Willebrand factor type C repeat (VWC), thrombospondin type 1 repeat (TSP1) and C-terminal cysteine-knot (CT) modules are all aligned tandem therein. The multiple functionality of CCN2 is thought to be enabled by the differential use of these modules when interacting with other molecules. In this study, we independently prepared all 4 purified module proteins of human CCN2, utilizing a secretory production system with Brevibacillus choshinensis and thus evaluated the cell biological effects of such single modules. In human umbilical vascular endothelial cells (HUVECs), VWC, TSP and CT modules, as well as a full-length CCN2, were capable of efficiently activating the ERK signal transduction cascade, whereas IGFBP was not. In contrast, the IGFBP module was found to prominently activate JNK in human chondrocytic HCS-2/8 cells, while the others showed similar effects at lower levels. In addition, ERK1/2 was modestly, but significantly activated by IGFBP and VWC in those cells. No single module, but a mixture of the 4 modules provoked a significant activation of p38 MAPK in HCS-2/8 cells, which was activated by the full-length CCN2. Therefore, the signals emitted by CCN2 can be highly differential, depending upon the cell types, which are thus enabled by the tetramodular structure. Furthermore, the cell biological effects of each module on these cells were also evaluated to clarify the relationship among the modules, the signaling pathways and biological outcomes. Our present results not only demonstrate that single CCN2 modules were potent activators of the intracellular signaling cascade to yield a biological response per se, while also providing new insight into the module-wise structural and functional relationship of a prototypic CCN family member, CCN2. (c) 2006 Elsevier Masson SAS. All rights reserved.

DOI： 10.1016/j.biochi.2006.07.007

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

T Shimo, S Kubota, N Yoshioka, S Ibaragi, S Isowa, T Eguchi, A Sasaki, M Takigawa

JOURNAL OF BONE AND MINERAL RESEARCH 21 ( 7 ) 1045 - 1059 2006年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER SOC BONE & MINERAL RES

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-tetradecanoylphorbol-13-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

Roles of PKC, PI3K and JNK in multiple transduction of CCN2/CTGF signals in chondrocytes

G Yosimichi, S Kubota, T Nishida, S Kondo, T Yanagita, K Nakao, T Takano-Yamamoto, M Takigawa

BONE 38 ( 6 ) 853 - 863 2006年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE INC

CCN2/connective tissue growth factor (CCN2/CTGF) is known to promote both the proliferation and differentiation of chondrocytes, which actions are mediated by ERK and p38 MAPK, respectively. In this study, we first re-evaluated the involvement of multiple MAPKs therein and found that JNK also mediated such CCN2 signals. Thereafter, we further analyzed the roles of upstream kinases. The involvement of PKC, PI3K and PKA in the CCN2 signaling to promote the maturation, proliferation and terminal differentiation of a human chondrocytic cell line, HCS-2/8 and rabbit primary growth cartilage cells was investigated. As a result, the PKC inhibitor calphostin C repressed all of the effects of CCN2, which were represented by increased synthesis of DNA and proteoglycans and the display of alkaline phosphatase activity. In addition, evaluation of the effect of the PI3K inhibitor wortmannin disclosed the contribution of PI3K in transducing CCN2 signals to promote chondrocyte hypertrophy. This signal was known to be mediated by PKB, which was translocated into the nucleus upon CCN2 stimulation. Of note, calphostin C showed inhibitory effects on the activation of p38 MAPK, ERK and also PKB, whereas it exerted no effect on JNK activation. These results suggest that PKC is a driver of multiple signal transducing kinases that promote the proliferation and differentiation of chondrocytes. The requirement of PI3K in transmitting the signal for terminal differentiation and PKC-independent signaling pathways for the promotion of chondrocytic growth and differentiation, which was mediated by JNK, were also uncovered. (c) 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2005.11.016

Possible role of LRP1, a CCN2 receptor, in chondrocytes

K Kawata, T Eguchi, S Kubota, H Kawaki, M Oka, S Minagi, M Takigawa

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 345 ( 2 ) 552 - 559 2006年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2006.04.109

岡山大学歯学部1年次生におけるテュートリアル教育-これまでの問題点と平成17年度に改善した内容

完山学, 久保田聡, 十川紀夫, 吉田登志子, 池亀美華, 市川博之, 岡本信, 小柳津功介, 川邊紀章, 坂本友紀, 塚本剛一, 土居潤一, 山近英樹, 西村英紀, 松村誠士, 窪木拓男

岡山歯学会雑誌 25 ( 1 ) 8 - 8 2006年6月

Hypoxic regulation of stability of connective tissue growth factor/CCN2 mRNA by 3’-untranslated region interacting with a cellular protein in human chondrosarcoma cells.

Kondo S, Kubota S, Mukudai Y, Moritani N, Nishida T, Matsushita H, Matsumoto S, Sugahara T, Takigawa M

Oncogene 25 ( 7 ) 1099 - 1110 2006年2月

Novel angiogenic inhibitor DN-9693 that inhibits post-transcriptional induction of connective tissue growth factor (CTGF/CCN2) by vascular endothelial growth factor in human endothelial cells

S Kondo, N Tanaka, S Kubota, Y Mukudai, G Yosimichi, T Sugahara, M Takigawa

MOLECULAR CANCER THERAPEUTICS 5 ( 1 ) 129 - 137 2006年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER ASSOC CANCER RESEARCH

Connective tissue growth factor (CTGF/CCN2) is a potent angiogenic factor. In this report, we describe for the first time that vascular endothelial growth factor (VEGF)mediated induction of the ctgf/ccn2 gene was a posttranscriptional event that was inhibited by a novel angiogenic inhibitor, DN-9693, in human umbilical vein endothelial cells. Steady-state mRNA levels of ctgf/ccn2 were remarkably increased by VEGF in a concentration-dependent manner, whereas the activity of the ctgf/ccn2 promoter was not responsive to VEGF as confirmed by a reporter gene assay and quantitative real-time PCR analysis. By employing a RNA degradation assay, we eventually found that the observed increase in the ctgf/ccn2 mRNA level was due to an increased stability of the mRNA induced by VEGF. DN-9693 at a dose of 0.1 to 2 ng/mL did not affect basal levels of ctgf/ccn2 mRNA; however, enhancement of ctgf/ccn2 mRNA expression by VEGF was specifically inhibited by DN-9693. Of importance, the inhibitory effects could be also ascribed to post-transcriptional regulation, because the VEGF-mediated increase in stability of ctgf/ccn2 mRNA was suppressed by DN-9693. Furthermore, we investigated the effects of DN-9693 on VEGF-induced activation of three subgroups of mitogen-activated protein kinase pathways and found that DN-9693 blocked the activation of these pathways by VEGF. These results suggest that VEGF increases ctgf/ccn2 mRNA stability through mitogen-activated protein kinase-mediated intracellular signaling cascade(s), which can be inhibited posttranscriptionally by a novel angiogenic inhibitor, DN-9693, in human umbilical vein endothelial cells.

DOI： 10.1158/1535-7163.MCT-05-0097

Expression and regulation of an antisense RNA transcript of the human connective tissue growth factor gene in human tumour cells

Seiji Kondo, Satoshi Kubota, Harumi Kawaki, Norifumi Moritani, Toshimasa Kagawa, Takaaki Ueno, Toshio Sugahara, Masaharu Takigawa

Asian Journal of Oral and Maxillofacial Surgery 18 ( 3 ) 172 - 179 2006年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Communications International Ltd

Objective: To characterise a natural antisense transcript of connective tissue growth factor. Materials and Methods: RNA from several cell lines was analysed by RNase protection assay to detect antisense transcripts. To characterise the regulatory aspect of the transcribed area, chimeras were constructed in which the firefly luciferase gene was fused with the corresponding segment of ctgf/ccn2, and the gene expression was monitored. Results: A natural antisense transcript complementary to the 3′-untranslated region of ctgf/ccn2 mRNA in cultured human tumour cells was detected. The luciferase gene fused with the full-length antisense 3′-untranslated region showed strikingly low levels of luciferase expression compared with the control. Based on a series of deletion analyses, the major repressive element was located in the middle portion within the 3′-untranslated region, which corresponded to the antisense transcribed area. Conclusion: These results suggest that controlled expression of antisense RNAs against the 3′-untranslated region of ctgf/ccn2 mRNA may be involved in the determination of phenotypes in certain oral malignancies. © 2006 Asian Association of Oral and Maxillofacial Surgeons.

DOI： 10.1016/S0915-6992(06)80014-2

軟骨組織の発生分化とCCNファミリー遺伝子

久保田聡, 滝川正春

Clinical Calcium 16,486-492 2006年

Effect of connective tissue growth factor (CCN2/CTGF) on proliferation and differentiation of mouse periodontal ligament-derived cells

Masahiro Asano, Satoshi Kubota, Tohru Nakanishi, Takashi Nishida, Tomoichiro Yamaai, Gen Yosimichi, Kazumi Ohyama, Tomosada Sugimoto, Yoji Murayama, Masaharu Takigawa

Cell Communication and Signaling 3 2005年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Background: CCN2/CTGF is known to be involved in tooth germ development and periodontal tissue remodeling, as well as in mesenchymal tissue development and regeneration. In this present study, we investigated the roles of CCN2/CTGF in the proliferation and differentiation of periodontal ligament cells (murine periodontal ligament-derived cell line: MPL) in vitro. Results: In cell cultures of MPL, the mRNA expression of the CCN2/CTGF gene was stronger in sparse cultures than in confluent ones and was significantly enhanced by TGF-β. The addition of recombinant CCN2/CTGF (rCCN2) to MPL cultures stimulated DNA synthesis and cell growth in a dose-dependent manner. Moreover, rCCN2 addition also enhanced the mRNA expression of alkaline phosphatase (ALPase), type I collagen, and periostin, the latter of which is considered to be a specific marker of the periosteum and periodontium
whereas it showed little effect on the mRNA expression of typical osteoblastic markers, e.g., osteopontin and osteocalcin. Finally, rCCN2/CTGF also stimulated ALPase activity and collagen synthesis. Conclusion: These results taken together suggest important roles of CCN2/ CTGF in the development and regeneration of periodontal tissue including the periodontal ligament. © 2005 Asano et al
licensee BioMed Central Ltd.

DOI： 10.1186/1478-811X-3-11

Translational repression by the cis-acting element of structure-anchored repression (CAESAR) of human ctgf/ccn2 mRNA

S Kubota, Y Mukudai, NH Moritani, K Nakao, K Kawata, M Takigawa

FEBS LETTERS 579 ( 17 ) 3751 - 3758 2005年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

The cis-acting element of structure-anchored repression (CAESAR) is a post-transcriptional regulatory element of gene expression, which is located in the 3'-untranslated region (UTR) of the human ccn2 gene (ctgflccn2). In this report, the repression mechanism of CAESAR, as well as the structural requirement, was investigated. Removal of minor stem-loops from CAESAR resulted in proportional attenuation of the repressive function, whereas removal of the single bulge or modification of primary nucleotide sequence did not affect its functionality. In light of functional mechanism, CAESAR exerted no significant effects on stability or nuclear export of the cis-linked mRNA. However, this element significantly interfered with the association of such mRNA on ribosome and slowed down the translation process thereafter in vitro. A translation repression mechanism by RNA secondary structure to determine the basal ctgflccn2 expression level was uncovered herein. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.febslet.2005.05.068

Collaborative action of M-CSF and CTGF/CCN2 in articular chondrocytes: Possible regenerative roles in articular cartilage metabolism

K Nakao, S Kubota, H Doi, T Eguchi, M Oka, T Fujisawa, T Nishida, M Takigawa

BONE 36 ( 5 ) 884 - 892 2005年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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. &COPY; 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2004.10.015

Comparable response of ccn1 with ccn2 genes upon arthritis: An in vitro evaluation with a human chondrocytic cell line stimulated by a set of cytokines

Norifumi H. Moritani, Satoshi Kubota, Toshio Sugahara, Masaharu Takigawa

Cell Communication and Signaling 3 2005年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

Background: The chondrosarcoma-derived HCS-2/8 has been known to be an excellent model of human articular chondrocytes. By mimicking the arthritic conditions through the treatment of HCS-2/8 cells with cytokines, we estimated the gene expression response of ccn1 and ccn2 during the course of joint inflammation in vitro. Results: In order to mimic the initiation of inflammation, HCS-2/8 cells were treated with tumor necrosis factor (TNF)-α. To induce pro-inflammatory or reparative responses, TGF-β was employed. Effects of an anti-inflammatory glucocorticoid were also evaluated. After stimulation, expression levels of ccn1 and ccn2 were quantitatively analyzed. Surprisingly, not only ccn2, but also ccn1 expression was repressed upon TNF-α stimulation, whereas both mRNAs were uniformly induced by transforming growth factor (TGF)-β and a glucocorticoid. Conclusion: These results describing the same response during the course of inflammation suggest similar and co-operative roles of these 2 ccn family members in the course of arthritis. © 2005 Moritani et al
licensee BioMed Central Ltd.

DOI： 10.1186/1478-811X-3-6

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

Y Mukudai, S Kubota, T Eguchi, S Kondo, K Nakao, M Takigawa

JOURNAL OF BIOLOGICAL CHEMISTRY 280 ( 5 ) 3166 - 3177 2005年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：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

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9
10
11
12