Faculty Profiles - TAKIGAWA Masaharu

Papers - TAKIGAWA Masaharu

Division display 181 - 200 of about 473 ／ All the affair displays >>

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 2007.4

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

A functional polymorphism in the 5 ' UTR of GDF5 is associated with susceptibility to osteoarthritis

Yoshinari Miyamoto, Akihiko Mabuchi, Dongquan Shi, Toshikazu Kubo, Yoshio Takatori, Susumu Saito, Mikihiro Fujioka, Akihiro Sudo, Atsumasa Uchida, Seizo Yamamoto, Koichi Ozaki, Masaharu Takigawa, Toshihiro Tanaka, Yusuke Nakamura, Qing Jiang, Shiro Ikegawa

NATURE GENETICS 39 ( 4 ) 529 - 533 2007.4

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Osteoarthritis (MIM 165720), characterized by degeneration of articular cartilage, is the most common form of human arthritis and a major concern for aging societies worldwide(1-3). Epidemiological and genetic studies have shown that osteoarthritis is a polygenic disease(1,4,5). Here, we report that the gene encoding growth differentiation factor 5 (GDF5) is associated with osteoarthritis in Asian populations. A SNP in the 5' UTR of GDF5 (+104T/ C; rs143383) showed significant association (P = 1.8 x 10(-13)) with hip osteoarthritis in two independent Japanese populations. This association was replicated for knee osteoarthritis in Japanese (P = 0.0021) and Han Chinese (P = 0.00028) populations. This SNP, located in the GDF5 core promoter, exerts allelic differences on transcriptional activity in chondrogenic cells, with the susceptibility allele showing reduced activity. Our findings implicate GDF5 as a susceptibility gene for osteoarthritis and suggest that decreased GDF5 expression is involved in the pathogenesis of osteoarthritis.

DOI： 10.1038/ng2005

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 2007.3

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 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 2007.3

Language：English

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

Prostaglandin E-2 downregulates TNF-alpha-induced production of matrix metalloproteinase-1 in HCS-2/8 chondrocytes by inhibiting Raf-1/MEK/ERK cascade through EP4 prostanoid receptor activation

Kazunari Fushimi, Shigeru Nakashima, Fukka You, Masaharu Takigawa, Katsuji Shimizu

JOURNAL OF CELLULAR BIOCHEMISTRY 100 ( 3 ) 783 - 793 2007.2

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

Matrix metalloproteinase-1 (MMP-1, collagenase-1) plays a pivotal role in the process of joint destruction in degenerative joint diseases. We have examined the regulation of MMP-1 production in human chondrocytic HCS-2/8 cells stimulated by tumor necrosis factor-alpha (TNF-alpha). In response to TNF-alpha, MMP-1 is induced and actively released from HCS-2/8 cells. The induction of MMP-1 expression correlates with activation of ERK1/2, MEK, and Raf-1, and is potently prevented by U0126, a selective inhibitor of MEK1/2 activation. In contrast, SB203580, a selective p38 mitogen-activated protein kinases (MAPK) inhibitor, had no effects on TNF-alpha-induced MMP-1 release. A serine/threonine kinase, Akt was not activated in TNF-alpha-stimulated HCS-2/8 cells. TNF-alpha stimulated the production of PGE(2) in addition to MMP-1 in HCS-2/8 cells. Exogenously added PGE(2) potently inhibited TNF-alpha-induced both MMP-1 production and activation of ERK1/2. The effects of PGE(2) were mimicked by ONO-AE1-329, a selective EP4 receptor agonist but not by butaprost, a selective EP2 agonist. In contrast, blockade of endogenously produced PGE(2) signaling by ONO-AE3-208, a selective EP4 receptor antagonist, enhanced TNF-alpha-induced MMP-1 production. Furthermore, the suppression of MMP-l production by exogenously added PGE(2) was reversed by ONO-AE3-208. Activation of EP4 receptor resulted in cAMP-mediated phosphorylation of Raf-1 on Ser259, a negative regulatory site, and blocked activation of Raf-1/MEK/ERK cascade. Taken together, these findings indicate that Raf-1/MEK/ERK signaling pathway plays a crucial role in the production of MMP-1 in HCS-2/8 cells in response to TNF-alpha, and that the produced PGE(2) downregulates the expression of MMP-1 by blockage of TNF-alpha-induced Raf-1 activation through EP4-PGE(2) receptor activation.

DOI： 10.1002/jcb.21099

Dopamine Receptor Presence in the Rat Area Postrema Identified by RT-PCR, Immunohistochemistry, and In Situ Hybridization

Izawa Shunji, Yamaai Tomoichiro, Mukudai Yoshiki, Yamaji Kozo, Nishitani Yoshihiro, Itota Toshiyuki, Matsuo Ryuji, Takigawa Masaharu, Yoshiyama Masahiro

Japanese Journal of Oral Biology 49 ( 4 ) 259 - 268 2007

Language：English Publisher：Japanese Association for Oral Biology

Dopamine (DA) is a major central nervous system (CNS) neurotransmitter with many important physiological activities. Investigations into the neuroanatomy and neurologic functions of the dopaminergic neural systems have generated much debate. Regarding neuroanatomy, physiological and pharmacological criteria have divided DA receptors into D1 and D2 subtypes. The genes encoding these subtypes have been cloned and classified into a D1 subfamily encompassing D1 and D5 receptors and a D2 subfamily with D2, D3, and D4. Based on the sequences of the cloned receptors, we prepared antibodies and riboprobes to elucidate the expression of the corresponding proteins and mRNAs in the rat area postrema (AP) by immunohistochemistry and in situ hybridization (ISH). The AP was obtained from adult male Sprague-Dawley rats undergoing brain surgery, and tissue samples were used for RT-PCR, immunohistochemistry, and ISH. The results showed that D2 and D5 receptors and their mRNAs exist in the rat AP. On the other hand, D1, D3, and D4 receptors and their mRNAs were not detected.

DOI： 10.2330/joralbiosci.49.259

結合組織成長因子CTGF/CCN2 Invited

服部高子, 久保田聡, 滝川正春

The Lung perspectives 15 ( 3 ) 331 - 335 2007

Language：Japanese Publisher：(株)メディカルレビュー社

結合組織成長因子(connective tissue growth factor;CTGF/CCN2)は前肥大軟骨細胞層が特異的に発現する遺伝子として、また、血管内皮細胞の培養上清中に存在する線維芽細胞の増殖・遊走促進因子として単離されたが、その発現部位は軟骨組織、血管内皮細胞だけでなく、脳をはじめとする神経系にも広がり、また、血小板に大量に蓄積されて体内を循環している。生理的には、正常な内軟骨性骨形成、血管新生、胚発育に必須であることが明らかになっており、細胞外マトリックス成分の合成を強く促進し、細胞外マトリックスに富む軟骨組織で高発現していることと密接に関連している。また、肺をはじめ、心臓、肝臓、腎臓、筋、膵臓などの組織における線維芽細胞では、トランスフォーミング増殖因子(TGF)-βの誘導に伴って遺伝子発現が誘導され、各組織の線維化、線維症の形成を促進することから、そのメディエーターとしての働きが注目されている。また、乳癌細胞で高度に発現していることが観察されているが、低酸素状態によってCTGF/CCN2の発現が誘導され、これにより血管新生が惹起されることが明らかになっている。(著者抄録)

Role of CCN2/CTGF/Hcs24 in bone growth Reviewed

Satoshi Kubota, Masaharu Takigawa

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

Language：English Publishing type：Part of collection (book) Publisher：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 2006.12

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

Expression of neurotrophins and their receptors tropomyosin-related kinases (Trk) under tension-stress during distraction osteogenesis

Ayako Aiga, Koji Asaumi, You-Jin Lee, Hiroaki Kadota, Shigeru Mitani, Toshifumi Ozaki, Masaharu Takigawa

ACTA MEDICA OKAYAMA 60 ( 5 ) 267 - 277 2006.10

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

The localization and expression of neurotrophins and their receptors during distraction osteogenesis was investigated in 72 male rat femurs (11 weeks old) to further clarify the concurrence of cellular and molecular events of new bone formation. After osteotomy, a 7-day lag phase was followed by distraction at the rate of 0.25 mm/12 h for 21 days (distraction phase), and a 7-day consolidation phase. The localization of neurotrophins (NGF, BDNF and NT-3) and their receptors tropomyosin-related kinases (TRKA, TRKB and TRKC) by immunostaining showed positive staining in bone forming cells in each stage, although the presence and staining intensity varied by cell type and phase. The expressions of NGF, BDNF and NT-3 by real-time polymerase chain reaction (real-time PCR) showed that the peak of the mRNA expression of NGF occurred 10 days after distraction. NT-3 increased during bone extension, but decreased when distraction stopped. In contrast, BDNF continued to increase gradually throughout the distraction and consolidation phases. These findings suggest that neurotrophins and their receptors may play different roles in endochondral and intramembranous ossification in distraction osteogenesis. The tension stress caused by distraction may stimulate the expression of neurotrophins and their receptors, and promote osteogenesis.

[Autoantigen and molecular chaperone in rheumatoid arthritis--their roles in metabolism of chondrocytes]. Reviewed

Hattori T, Takigawa M

Clinical calcium 16 ( 9 ) 1553 - 1556 2006.9

Language：Japanese Publishing type：Research paper (scientific journal)

The endoplasmic reticulum chaperone; heat shock protein/rheumatoid arthritis-related antigen (HSP47/RA-A47), in addition to its important intercellular functions for collagen maturation and secretion, has chondrocytes-destructive roles such as induction of endoplasmic reticulum (ER)-stress and metabolic gene expressions result in apoptosis when HSP47/RA-A47 is downregulated. Extracellular HSP47/RA-A47 may act as an autoantigen, but also regulate autoimmune inflammation. It is, therefore, a potential new biologic therapy for rheumatoid arthritis.

硬組織モジュレーターCCN/CTGFのIGFBPモジュレーターを介した軟骨細胞増殖・分化促進効果

川木晴美, 久保田聡, 湊雅直, 近藤誠二, 滝川正春

Journal of Oral Biosciences 48 ( Suppl. ) 113 - 113 2006.9

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 2006.7

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

結合組織成長因子CCN2/CTGFによる骨髄由来間質細胞の細胞接着、遊走の亢進とシグナル伝達経路の活性化

大野充昭, 藤澤拓生, 久保田聡, 園山亘, 秋山謙太郎, 西田崇, 滝川正春, 窪木拓男

日本骨代謝学会学術集会プログラム抄録集 24回 248 - 248 2006.7

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 2006.6

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. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2006.04.109

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 2006.6

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

Dexamethasone induces connective tissue growth factor expression in renal tubular epithelial cells in a mouse strain-specific manner

H Okada, T Kikuta, T Inoue, Y Kanno, S Ban, T Sugaya, M Takigawa, H Suzuki

AMERICAN JOURNAL OF PATHOLOGY 168 ( 3 ) 737 - 747 2006.3

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC INVESTIGATIVE PATHOLOGY, INC

Connective tissue growth factor (CTGF), a downstream mediator of transforming growth factor-beta 1, mediates mesangial cell/fibroblast proliferation and extracellular matrix production by renal cells. Here, we show that renal tubular epithelial cells from patients with minimal change nephritic syndrome produced CTGF after glucocorticoid treatment. in addition, the glucocorticoid dexamethasone (DEX) increased CTGF mRNA levels in the kidneys of C57B6 but not SJL mice and produced intermediate CTGF mRNA levels in the kidneys of F1 (C57B6 X SJL) mice, midway between the levels found for parental strains. DEX also increased CTGF mRNA levels in cultured tubular epithelial cells derived from C57B6 (mProx24) but not SJL (MCT) mice via transcriptional up-regulation of CTGF mRNA. Transient transfection experiments using luciferase reporter constructs bearing CTGF promoter fragments revealed that the -897-to-628-bp fragment contained DEX-responsive positive regulatory elements, which were active in mProx24 but not MCT cells. Long-term DEX treatment resulted in fibronectin deposition in the kidneys of C57B6 but not SJL mice, and this effect was inhibited by co-administration of CTGF anti-sense oligodeoxynucleotides. Thus, glucocorticoid-induced renal fibrogenesis seems to be influenced by genetic background, with the critical DEX-responsive elements in the -897-to-628-bp region of the CTGF promoter.

DOI： 10.2353/ajpath.2006.050656

Transcriptional regulation of the cartilage intermediate layer protein (CILP) gene Reviewed

M Mori, M Nakajima, Y Mikami, S Seki, M Takigawa, T Kubo, S Ikegawa

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 341 ( 1 ) 121 - 127 2006.3

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

Cartilage intermediate layer protein (CILP) is an extracellular matrix protein abundant in cartilaginous tissues. CILP is implicated in common musculoskeletal disorders, including osteoarthritis and lumbar disc disease. Regulation of the CILP gene is largely unknown, however. We have found that CILP mRNA expression is induced by TGF-beta 1 and dependent upon signaling via TGF-beta receptors. TGF-beta 1 induction of CILP is mediated by Smad3, which acts directly through cis-elements in the CILP promoter region. Pathways other than Smad3 also arc involved in TGF-beta 1 induction of CILP. These observations, together with the finding that CILP protein binds and inhibits TGF-beta 1, suggest that CILP and TGF-beta 1 may form a functional feedback loop that controls chondrocyte metabolism. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2005.12.159

Locally produced estrogen promotes fetal rat metatarsal bone growth; an effect mediated through increased chondrocyte proliferation and decreased apoptosis

AS Chagin, D Chrysis, M Takigawa, EM Ritzen, L Savendahl

JOURNAL OF ENDOCRINOLOGY 188 ( 2 ) 193 - 203 2006.2

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

The importance of estrogens for the regulation of longitudinal bone growth is unequivocal. However, any local effect of estrogens in growth plate cartilage has been debated. Recently, several enzymes essential for estrogen synthesis were shown to be expressed in rat growth plate chondrocytes. Local production of 17 beta-estradiol (E2) has also been demonstrated in rat costal chondrocytes. We aimed to determine the functional role of locally produced estrogen in growth plate cartilage. The human chondrocyte-like cell line HCS-2/8 was used to study estrogen effects on cell proliferation (3 H-labeled thymidine uptake) and apoptosis (cell death detection ELISA kit). Chondrocyte production of E2 was measured by RIA and organ cultures of fetal rat metatarsal bones were used to study the effects of estrogen on longitudinal growth rate. We found that significant amounts of E2 were produced by HCS-2/8 chondrocytes (64(.)1 +/- 5(.)3 fmol/3 days/10(6) cells). The aromatase inhibitor letrozole (1 mu M) and the pure estrogen receptor antagonist ICI 182,780 (10 mu M) inhibited proliferation of HCS-2/8 chondrocytes by 20% (P < 0(.)01) and almost 50% (P < 0(.)001), respectively. Treatment with ICI 182,780 (10 mu M) increased apoptosis by 228% (P < 0(.)05). Co-treatment with either caspase-3 or pan-caspase inhibitors completely blocked ICI 182,780-induced apoptosis (P < 0(.)001 vs ICI 182,780 only). Moreover, both ICI 182,780 (10 mu M) and letrozole (1 mu M) decreased longitudinal growth of fetal rat metatarsal bones after 7 days of culture (P < 0-01). In conclusion, our data clearly show that chondrocytes endogenously produce E2 and that locally produced estrogen stimulates chondrocyte proliferation and protects from spontaneous apoptosis. In addition, longitudinal growth is promoted by estrogens locally produced within the epiphyseal growth plate.

DOI： 10.1677/joe.1.06364

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

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

ONCOGENE 25 ( 7 ) 1099 - 1110 2006.2

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Connective tissue growth factor (CTGF/CCN2) can be induced by various forms of stress such as exposure to high glucose, mechanical load, or hypoxia. Here, we investigated the molecular mechanism involved in the induction of ctgf/ccn2 by hypoxia in a human chondrosarcoma cell line, HCS-2/8. Hypoxia increased the ctgf/ccn2 mRNA level by altering the 3'-untranslated region (UTR)-mediated mRNA stability without requiring de novo protein synthesis. After a series of extensive analyses, we eventually found that the cis-repressive element of 84 bases within the 3'-UTR specifically bound to a cytoplasmic/nuclear protein. By conducting a UV crosslinking assay, we found the cytoplasmic/nuclear protein to be a 35 kDa molecule that bound to the cis-element in a hypoxia-inducible manner. These results suggest that a cis-element in the 3'-UTR of ctgf/ccn2 mRNA and trans-factor counterpart(s) play an important role in the post-transcriptional regulation by determining the stability of ctgf/ccn2 mRNA.

DOI： 10.1038/sj.onc.1209129

　 PREV - NEXT 　

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24