MDPI AG Acta Medica Okayama 1422-0067 26 19 2025 Critical Requirement of Senescence-Associated CCN3 Expression in CD44-Positive Stem Cells for Osteoarthritis Progression 9630 EN Janvier Habumugisha Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ryuichiro Okuda Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazuki Hirose Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Miho Kuwahara Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ziyi Wang Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Mitsuaki Ono Department of Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hiroshi Kamioka Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage breakdown, synovial inflammation, and subchondral bone remodeling. Previous studies have shown that cellular communication network factor 3 (CCN3) expression increases with age in cartilage, and its overexpression promotes OA-like changes by inducing senescence-associated secretory phenotypes. This study aimed to investigate the effect of Ccn3 knockout (KO) on OA development using a murine OA model. Destabilization of the medial meniscus (DMM) surgery was performed in wild-type (WT) and Ccn3-KO mice. Histological scoring and staining were used to assess cartilage degeneration and proteoglycan loss. Gene and protein expressions of catabolic enzyme (Mmp9), hypertrophic chondrocyte marker (Col10a1), senescence marker, and cyclin-dependent kinase inhibitor 1A (Cdkn1a) were evaluated. Single-cell RNA sequencing (scRNA-seq) data from WT and Sox9-deficient cartilage were reanalyzed to identify Ccn3+ progenitor populations. Immunofluorescence staining assessed CD44 and Ki67 expression in articular cartilage. The effects of Ccn3 knockdown on IL-1β-induced Mmp13 and Adamts5 expression in chondrocytes were examined in vitro. Ccn3 KO mice exhibited reduced cartilage degradation and catabolic gene expression compared with WT mice post-DMM. scRNA-seq revealed enriched Ccn3-Cd44 double-positive cells in osteoblast progenitor, synovial mesenchymal stem cell, and mesenchymal stem cell clusters. Immunofluorescence showed increased CCN3+/CD44+ cells in femoral and tibial cartilage and meniscus. Ki67+ cells were significantly increased in DMM-treated Ccn3 KO cartilage, mostly CD44+. In vitro Ccn3 knockdown attenuated IL-1β-induced Mmp13 and Adamts5 expressions in chondrocytes. Ccn3 contributes to OA pathogenesis by promoting matrix degradation, inducing hypertrophic changes, and restricting progenitor cell proliferation, highlighting Ccn3 as a potential therapeutic target for OA. No potential conflict of interest relevant to this article was reported.

Public Library Science Acta Medica Okayama 1932-6203 17 11 2022 Cysteinyl leukotriene receptor 1 is dispensable for osteoclast differentiation and bone resorption e0277307 EN Hirofumi Fujita Department of Cytology and Histology, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Aoi Ando Faculty of Medicine, Okayama University Medical School Yohei Mizusawa Faculty of Medicine, Okayama University Medical School Mitsuaki Ono Department of Molecular Biology and Biochemistry, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Munenori Habuta Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshitaka Oohashi Department of Molecular Biology and Biochemistry, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Hideyo Ohuchi Department of Cytology and Histology, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical Sciences Cysteinyl leukotriene receptor 1 (CysLTR1) is a G protein-coupled receptor for the inflammatory lipid mediators cysteinyl leukotrienes, which are involved in smooth muscle constriction, vascular permeability, and macrophage chemokine release. The Cysltr1 gene encoding CysLTR1 is expressed in the macrophage lineage, including osteoclasts, and the CysLTR1 antagonist Montelukast has been shown to suppress the formation of osteoclasts. However, it currently remains unclear whether CysLTR1 is involved in osteoclast differentiation and bone loss. Therefore, to clarify the role of CysLTR1 in osteoclastogenesis and pathological bone loss, we herein generated CysLTR1 loss-of-function mutant mice by disrupting the cysltr1 gene using the CRISPR-Cas9 system. These mutant mice had a frameshift mutation resulting in a premature stop codon (Cysltr1 KO) or an in-frame mutation causing the deletion of the first extracellular loop (Cysltr1(Delta 105)). Bone marrow macrophages (BMM) from these mutant mice lost the intracellular flux of calcium in response to leukotriene D-4, indicating that these mutants completely lost the activity of CysLTR1 without triggering genetic compensation. However, disruption of the Cysltr1 gene did not suppress the formation of osteoclasts from BMM in vitro. We also demonstrated that the CysLTR1 antagonist Montelukast suppressed the formation of osteoclasts without functional CysLTR1. On the other hand, disruption of the Cysltr1 gene partially suppressed the formation of osteoclasts stimulated by leukotriene D-4 and did not inhibit that by glutathione, functioning as a substrate in the synthesis of cysteinyl leukotrienes. Disruption of the Cysltr1 gene did not affect ovariectomy-induced osteoporosis or lipopolysaccharide-induced bone resorption. Collectively, these results suggest that the CysLT-CysLTR1 axis is dispensable for osteoclast differentiation in vitro and pathological bone loss, while the leukotriene D-4-CysTR1 axis is sufficient to stimulate osteoclast formation. We concluded that the effects of glutathione and Montelukast on osteoclast formation were independent of CysLTR1. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1422-0067 23 23 2022 Elevated Expression of CCN3 in Articular Cartilage Induces Osteoarthritis in Hip Joints Irrespective of Age and Weight Bearing 15311 EN Kazuki Hirose Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Miho Kuwahara Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Eiji Nakata Department of Orthopaedic Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Tomonori Tetsunaga Department of Orthopaedic Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kazuki Yamada Department of Orthopaedic Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Kenta Saiga Department of Orthopaedic Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Masaharu Takigawa Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Toshifumi Ozaki Department of Orthopaedic Surgery, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Osteoarthritis (OA) occurs not only in the knee but also in peripheral joints throughout the whole body. Previously, we have shown that the expression of cellular communication network factor 3 (CCN3), a matricellular protein, increases with age in knee articular cartilage, and the misexpression of CCN3 in cartilage induces senescence-associated secretory phenotype (SASP) factors, indicating that CCN3 promotes cartilage senescence. Here, we investigated the correlation between CCN3 expression and OA degenerative changes, principally in human femoral head cartilage. Human femoral heads obtained from patients who received total hip arthroplasty were categorized into OA and femoral neck fracture (normal) groups without significant age differences. Gene expression analysis of RNA obtained from femoral head cartilage revealed that CCN3 and MMP-13 expression in the non-weight-bearing part was significantly higher in the OA group than in the normal group, whereas the weight-bearing OA parts and normal cartilage showed no significant differences in the expression of these genes. The expression of COL10A1, however, was significantly higher in weight-bearing OA parts compared with normal weight-bearing parts, and was also higher in weight-bearing parts compared with non-weight-bearing parts in the OA group. In contrast, OA primary chondrocytes from weight-bearing parts showed higher expression of CCN3, p16, ADAMTS4, and IL-1 beta than chondrocytes from the corresponding normal group, and higher ADAMTS4 and IL-1 beta in the non-weight-bearing part compared with the corresponding normal group. Acan expression was significantly lower in the non-weight-bearing group in OA primary chondrocytes than in the corresponding normal chondrocytes. The expression level of CCN3 did not show significant differences between the weight-bearing part and non-weight-bearing part in both OA and normal primary chondrocytes. Immunohistochemical analysis showed accumulated CCN3 and aggrecan neoepitope staining in both the weight-bearing part and non-weight-bearing part in the OA group compared with the normal group. The CCN3 expression level in cartilage had a positive correlation with the Mankin score. X-ray analysis of cartilage-specific CCN3 overexpression mice (Tg) revealed deformation of the femoral and humeral head in the early stage, and immunohistochemical analysis showed accumulated aggrecan neoepitope staining as well as CCN3 staining and the roughening of the joint surface in Tg femoral and humeral heads. Primary chondrocytes from the Tg femoral head showed enhanced expression of Ccn3, Adamts5, p16, Il-6, and Tnf alpha, and decreased expression of Col2a1 and -an. These findings indicate a correlation between OA degenerative changes and the expression of CCN3, irrespective of age and mechanical loading. Furthermore, the Mankin score indicates that the expression level of Ccn3 correlates with the progression of OA. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1422-0067 23 11 2022 Molecular and Genetic Interactions between CCN2 and CCN3 behind Their Yin-Yang Collaboration 5887 EN Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazumi Kawata Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takako Hattori Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takashi Nishida Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Cellular communication network factor (CCN) 2 and 3 are the members of the CCN family that conduct the harmonized development of a variety of tissues and organs under interaction with multiple biomolecules in the microenvironment. Despite their striking structural similarities, these two members show contrastive molecular functions as well as temporospatial emergence in living tissues. Typically, CCN2 promotes cell growth, whereas CCN3 restrains it. Where CCN2 is produced, CCN3 disappears. Nevertheless, these two proteins collaborate together to execute their mission in a yin-yang fashion. The apparent functional counteractions of CCN2 and CCN3 can be ascribed to their direct molecular interaction and interference over the cofactors that are shared by the two. Recent studies have revealed the mutual negative regulation systems between CCN2 and CCN3. Moreover, the simultaneous and bidirectional regulatory system of CCN2 and CCN3 is also being clarified. It is of particular note that these regulations were found to be closely associated with glycolysis, a fundamental procedure of energy metabolism. Here, the molecular interplay and metabolic gene regulation that enable the yin-yang collaboration of CCN2 and CCN3 typically found in cartilage development/regeneration and fibrosis are described. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2076-2607 10 5 2022 Maternal Gut Microbiome Decelerates Fetal Endochondral Bone Formation by Inducing Inflammatory Reaction 1000 EN Yoko Uchida-Fukuhara Department of Oral Morphology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takako Hattori Department of Biochemistry and Molecular Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Shanqi Fu Department of Biochemistry and Molecular Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Sei Kondo Department of Biochemistry and Molecular Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Miho Kuwahara Department of Biochemistry and Molecular Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Daiki Fukuhara Department of Preventive Dentistry, Okayama University Hospital Md Monirul Islam Department of Preventive Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kota Kataoka Department of Preventive Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Daisuke Ekuni Department of Preventive Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Manabu Morita Department of Preventive Dentistry, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Mika Iikegame Department of Oral Morphology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Hirohiko Okamura Department of Oral Morphology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University To investigate the effect of the maternal gut microbiome on fetal endochondral bone formation, fetuses at embryonic day 18 were obtained from germ-free (GF) and specific-pathogen-free (SPF) pregnant mothers. Skeletal preparation of the fetuses' whole bodies did not show significant morphological alterations; however, micro-CT analysis of the tibiae showed a lower bone volume fraction in the SPF tibia. Primary cultured chondrocytes from fetal SPF rib cages showed a lower cell proliferation and lower accumulation of the extracellular matrix. RNA-sequencing analysis showed the induction of inflammation-associated genes such as the interleukin (IL) 17 receptor, IL 6, and immune-response genes in SPF chondrocytes. These data indicate that the maternal gut microbiome in SPF mice affects fetal embryonic endochondral ossification, possibly by changing the expression of genes related to inflammation and the immune response in fetal cartilage. The gut microbiome may modify endochondral ossification in the fetal chondrocytes passing through the placenta. No potential conflict of interest relevant to this article was reported.

Springer Science and Business Media LLC Acta Medica Okayama 1873-9601 15 1 2021 Bipartite regulation of cellular communication network factor 2 and fibroblast growth factor 1 genes by fibroblast growth factor 1 through histone deacetylase 1 and fork head box protein A1 81 91 EN Abdellatif Elseoudi Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takashi Nishida Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Tomomi Mizukawa Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takako Hattori Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Kazumi Kawata Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Eman A. Taha Department of Dental Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Masaharu Takigawa Advanced Research Center for Oral and Craniofacial Sciences, Dental School, Okayama University Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Fibroblast growth factor 1 (FGF-1) is the first FGF family member, and it induces proliferation of fibroblasts and other types of the cells. However, recent studies are uncovering unexpected functions of this molecule. Our previous study redefined this growth factor as a catabolic molecule produced in cartilage upon metabolic insult. Indeed, FGF-1 was found to repress the gene expression of cellular communication network factor 2 (CCN2), which protects and regenerates cartilage, amplifying its own production through positive feedback regulation. In the present study, we investigated the molecular mechanism of this bipartite CCN2 repression and FGF1 activation by FGF-1 in chondrocytes. Repression of CCN2 and induction of FGF1 in human chondrocytic cells were both partly abolished by valproic acid, an inhibitor of histone deacetylase 1 (HDAC1), indicating the involvement of chromatin remodeling by histone acetylation in this system. In contrast, RNA degradation analysis suggested no contribution of post-transcriptional regulation of the mRNA stability to the effects conferred by FGF-1. Suspecting a regulation by a specific transcription factor, we next sought a candidate in silico from a large dataset. As a result, we found fork head box protein A1 (FOXA1) as the transcription factor that bound to both CCN2 and FGF1 loci. Functional analysis demonstrated that FOXA1 silencing significantly attenuated the CCN2 repression and FGF1 induction caused by FGF1. These findings collectively indicate that the bipartite regulation by FGF-1 is enabled by the combination of chromatin remodeling by HDACs and transcriptional modulation by FOXA1 with unknown transcriptional coactivators of opposite functionalities. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1422-0067 21 20 2020 CCN3 (NOV) Drives Degradative Changes in Aging Articular Cartilage 7556 EN Miho Kuwahara Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Koichi Kadoya Department of Oral and Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Sei Kondo Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shanqi Fu Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshiko Miyake Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Ayako Ogo Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Mitsuaki Ono Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takayuki Furumatsu Department of Orthopedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Eiji Nakata Department of Orthopedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Sasaki Department of Biochemistry, Faculty of Medicine, Oita University Shogo Minagi Department of Occlusal and Oral Functional Rehabilitation, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masaharu Takigawa Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Aging is a major risk factor of osteoarthritis, which is characterized by the degeneration of articular cartilage. CCN3, a member of the CCN family, is expressed in cartilage and has various physiological functions during chondrocyte development, differentiation, and regeneration. Here, we examine the role of CCN3 in cartilage maintenance. During aging, the expression of Ccn3 mRNA in mouse primary chondrocytes from knee cartilage increased and showed a positive correlation with p21 and p53 mRNA. Increased accumulation of CCN3 protein was confirmed. To analyze the effects of CCN3 in vitro, either primary cultured human articular chondrocytes or rat chondrosarcoma cell line (RCS) were used. Artificial senescence induced by H2O2 caused a dose-dependent increase in Ccn3 gene and CCN3 protein expression, along with enhanced expression of p21 and p53 mRNA and proteins, as well as SA-beta gal activity. Overexpression of CCN3 also enhanced p21 promoter activity via p53. Accordingly, the addition of recombinant CCN3 protein to the culture increased the expression of p21 and p53 mRNAs. We have produced cartilage-specific CCN3-overexpressing transgenic mice, and found degradative changes in knee joints within two months. Inflammatory gene expression was found even in the rib chondrocytes of three-month-old transgenic mice. Similar results were observed in human knee articular chondrocytes from patients at both mRNA and protein levels. These results indicate that CCN3 is a new senescence marker of chondrocytes, and the overexpression of CCN3 in cartilage may in part promote chondrocyte senescence, leading to the degeneration of articular cartilage through the induction of p53 and p21. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1422-0067 21 8 2020 Roles of Interaction between CCN2 and Rab14 in Aggrecan Production by Chondrocytes EN Mitsuhiro Hoshijima Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Eriko Aoyama Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takashi Nishida Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Hiroshi Kamioka Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Masaharu Takigawa Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School/Graduate School of Medicine, Dentistry and Pharmaceutical Sciences To identify proteins that cooperate with cellular communication network factor 2 (CCN2), we carried out GAL4-based yeast two-hybrid screening using a cDNA library derived from the chondrocytic cell line HCS-2/8. Rab14 GTPase (Rab14) polypeptide was selected as a CCN2-interactive protein. The interaction between CCN2 and Rab14 in HCS-2/8 cells was confirmed using the in situ proximity ligation assay. We also found that CCN2 interacted with Rab14 through its IGFBP-like domain among the four domains in CCN2 protein. To detect the colocalization between CCN2 and Rab14 in the cells in detail, CCN2, wild-type Rab14 (Rab14WT), a constitutive active form (Rab14CA), and a dominant negative form (Rab14DN) of Rab14 were overexpressed in monkey kidney-tissue derived COS7 cells. Ectopically overexpressed Rab14 showed a diffuse cytosolic distribution in COS7 cells; however, when Rab14WT was overexpressed with CCN2, the Rab14WT distribution changed to dots that were evenly distributed within the cytosol, and both Rab14 and CCN2 showed clear colocalization. When Rab14CA was overexpressed with CCN2, Rab14CA and CCN2 also showed good localization as dots, but their distribution was more widespread within cytosol. The coexpression of Rab14DN and CCN2 also showed a dotted codistribution but was more concentrated in the perinuclear area. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the reduction in RAB14 or CCN2 mRNA by their respective siRNA significantly enhanced the expression of ER stress markers, BIP and CHOP mRNA in HCS-2/8 chondrocytic cells, suggesting that ER and Golgi stress were induced by the inhibition of membrane vesicle transfer via the suppression of CCN2 or Rab14. Moreover, to study the effect of the interaction between CCN2 and its interactive protein Rab14 on proteoglycan synthesis, we overexpressed Rab14WT or Rab14CA or Rab14DN in HCS-2/8 cells and found that the overexpression of Rab14DN decreased the extracellular proteoglycan accumulation more than the overexpression of Rab14WT/CA did in the chondrocytic cells. These results suggest that intracellular CCN2 is associated with Rab14 on proteoglycan-containing vesicles during their transport from the Golgi apparatus to endosomes in chondrocytes and that this association may play a role in proteoglycan secretion by chondrocytes. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1422-0067 21 5 2020 Retrotransposons Manipulating Mammalian Skeletal Development in Chondrocytes 1564 EN Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takanori Ishikawa Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kazumi Kawata Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takashi Nishida Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Retrotransposons are genetic elements that copy and paste themselves in the host genome through transcription, reverse-transcription, and integration processes. Along with their proliferation in the genome, retrotransposons inevitably modify host genes around the integration sites, and occasionally create novel genes. Even now, a number of retrotransposons are still actively editing our genomes. As such, their profound role in the evolution of mammalian genomes is obvious; thus, their contribution to mammalian skeletal evolution and development is also unquestionable. In mammals, most of the skeletal parts are formed and grown through a process entitled endochondral ossification, in which chondrocytes play central roles. In this review, current knowledge on the evolutional, physiological, and pathological roles of retrotransposons in mammalian chondrocyte differentiation and cartilage development is summarized. The possible biological impact of these mobile genetic elements in the future is also discussed. No potential conflict of interest relevant to this article was reported.

BIOSCIENTIFICA Acta Medica Okayama 0022-0795 241 2 2019 Circadian production of melatonin in cartilage modifies rhythmic gene expression 161 173 EN Shanqi Fu Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Miho Kuwahara Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoko Uchida Department of Preventive Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Sei Kondo Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Daichi Hayashi Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yuji Shimomura Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Asami Takagaki Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takashi Nishida Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yusuke Maruyama Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University Mika Ikegame Department of Oral Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Atsuhiko Hattori Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University Satoshi Kubota Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takako Hattori Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Endochondral ossification, including bone growth and other metabolic events, is regulated by circadian rhythms. Herein, we provide evidence that melatonin has a direct effect on the circadian rhythm of chondrocytes. We detected mRNA expression of the genes which encode the melatonin-synthesizing enzymes AANAT (arylalkylamine N-acetyltransferase) and HIOMT (hydroxyindole O-methyltransferase), as well as the melatonin receptors MT1 and MT2 in mouse primary chondrocytes and cartilage. Production of melatonin was confirmed by mass spectrometric analysis of primary rat and chick chondrocytes. Addition of melatonin to primary mouse chondrocytes caused enhanced cell growth and increased expression of Col2a1, Aggrecan, and Sox9, but inhibited Col10a1 expression in primary BALB/c mouse chondrocytes. Addition of luzindole, an MT1 and MT2 antagonist, abolished these effects. These data indicate that chondrocytes produce melatonin, which regulates cartilage growth and maturation via the MT1 and MT2 receptors. Kinetic analysis showed that melatonin caused rapid upregulation of Aanat, Mt1, Mt2, and Pthrp expression, followed by Sox9 and Ihh. Furthermore, expression of the clock gene Bmal1 was induced, while that of Per1 was downregulated. Chronobiological analysis of synchronized C3H mouse chondrocytes revealed that melatonin induced the cyclic expression of Aanat and modified the cyclic rhythm of Bmal1, Mt1, and Mt2. In contrast, Mt1 and Mt2 showed different rhythms from Bmal1 and Aanat, indicating the existence of different regulatory genes. Our results indicate that exogenous and endogenous melatonin work in synergy in chondrocytes to adjust rhythmic expression to the central suprachiasmatic nucleus clock. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 0730-2312 115 5 2014 CCN2 as a Novel Molecule Supporting Energy Metabolism of Chondrocytes 854 865 EN Aya Maeda-Uematsu Satoshi Kubota Harumi Kawaki Kazumi Kawata Yoshiaki Miyake Takako Hattori Takashi Nishida Norifumi Moritani Karen M. Lyons Seiji Iida Masaharu Takigawa CCN2/connective tissue growth factor (CTGF) is a unique molecule that promotes both chondrocytic differentiation and proliferation through its matricellular interaction with a number of extracellular biomolecules. This apparently contradictory functional property of CCN2 suggests its certain role in basic cellular activities such as energy metabolism, which is required for both proliferation and differentiation. Comparative metabolomic analysis of costal chondrocytes isolated from wild-type and Ccn2-null mice revealed overall impaired metabolism in the latter. Among the numerous metabolites analyzed, stable reduction in the intracellular level of ATP, GTP, CTP, or UTP was observed, indicating a profound role of CCN2 in energy metabolism. Particularly, the cellular level of ATP was decreased by more than 50% in the Ccn2-null chondrocytes. The addition of recombinant CCN2 (rCCN2) to cultured Ccn2-null chondrocytes partly redeemed the cellular ATP level attenuated by Ccn2 deletion. Next, in order to investigate the mechanistic background that mediates the reduction in ATP level in these Ccn2-null chondrocytes, we performed transcriptome analysis. As a result, several metabolism-associated genes were found to have been up-regulated or down-regulated in the mutant mice. Up-regulation of a number of ribosomal protein genes was observed upon Ccn2 deletion, whereas a few genes required for aerobic and anaerobic ATP production were down-regulated in the Ccn2-null chondrocytes. Among such genes, reduction in the expression of the enolase 1 gene was of particular note. These findings uncover a novel functional role of CCN2 as a metabolic supporter in the growth-plate chondrocytes, which is required for skeletogenesis in mammals. No potential conflict of interest relevant to this article was reported.

Public Library Science Acta Medica Okayama 1932-6203 8 3 2013 Cartilage-Specific Over-Expression of CCN Family Member 2/Connective Tissue Growth Factor (CCN2/CTGF) Stimulates Insulin-Like Growth Factor Expression and Bone Growth EN Nao Tomita Takako Hattori Shinsuke Itoh Eriko Aoyama Mayumi Yao Takashi Yamashiro Masaharu Takigawa Previously we showed that CCN family member 2/connective tissue growth factor (CCN2) promotes the proliferation, differentiation, and maturation of growth cartilage cells in vitro. To elucidate the specific role and molecular mechanism of CCN2 in cartilage development in vivo, in the present study we generated transgenic mice overexpressing CCN2 and analyzed them with respect to cartilage and bone development. Transgenic mice were generated expressing a ccn2/lacZ fusion gene in cartilage under the control of the 6 kb-Col2a1-enhancer/promoter. Changes in cartilage and bone development were analyzed histologically and immunohistologically and also by micro CT. Primary chondrocytes as well as limb bud mesenchymal cells were cultured and analyzed for changes in expression of cartilage-related genes, and non-transgenic chondrocytes were treated in culture with recombinant CCN2. Newborn transgenic mice showed extended length of their long bones, increased content of proteoglycans and collagen II accumulation. Micro-CT analysis of transgenic bones indicated increases in bone thickness and mineral density. Chondrocyte proliferation was enhanced in the transgenic cartilage. In in vitro short-term cultures of transgenic chondrocytes, the expression of col2a1, aggrecan and ccn2 genes was substantially enhanced; and in long-term cultures the expression levels of these genes were further enhanced. Also, in vitro chondrogenesis was strongly enhanced. IGF-I and IGF-II mRNA levels were elevated in transgenic chondrocytes, and treatment of non-transgenic chondrocytes with recombinant CCN2 stimulated the expression of these mRNA. The addition of CCN2 to non-transgenic chondrocytes induced the phosphorylation of IGFR, and ccn2-overexpressing chondrocytes showed enhanced phosphorylation of IGFR. Our data indicates that the observed effects of CCN2 may be mediated in part by CCN2-induced overexpression of IGF-I and IGF-II. These findings indicate that CCN2-overexpression in transgenic mice accelerated the endochondral ossification processes, resulting in increased length of their long bones. Our results also indicate the possible involvement of locally enhanced IGF-I or IGF-II in this extended bone growth. No potential conflict of interest relevant to this article was reported.

Public Library Science Acta Medica Okayama 1932-6203 8 8 2013 CCN Family Member 2/Connective Tissue Growth Factor (CCN2/CTGF) Has Anti-Aging Effects That Protect Articular Cartilage from Age-Related Degenerative Changes EN Shinsuke Itoh Takako Hattori Nao Tomita Eriko Aoyama Yasutaka Yutani Takashi Yamashiro Masaharu Takigawa To examine the role of connective tissue growth factor CCN2/CTGF (CCN2) in the maintenance of the articular cartilaginous phenotype, we analyzed knee joints from aging transgenic mice (TG) overexpressing CCN2 driven by the Col2a1 promoter. Knee joints from 3-, 14-, 40-, and 60-day-old and 5-, 12-, 18-, 21-, and 24-month-old littermates were analyzed. Ccn2-LacZ transgene expression in articular cartilage was followed by X-gal staining until 5 months of age. Overexpression of CCN2 protein was confirmed through all ages in TG articular cartilage and in growth plates. Radiographic analysis of knee joints showed a narrowing joint space and other features of osteoarthritis in 50% of WT, but not in any of the TG mice. Transgenic articular cartilage showed enhanced toluidine blue and safranin-O staining as well as chondrocyte proliferation but reduced staining for type X and I collagen and MMP-13 as compared with those parameters for WT cartilage. Staining for aggrecan neoepitope, a marker of aggrecan degradation in WT articular cartilage, increased at 5 and 12 months, but disappeared at 24 months due to loss of cartilage; whereas it was reduced in TG articular cartilage after 12 months. Expression of cartilage genes and MMPs under cyclic tension stress (CTS) was measured by using primary cultures of chondrocytes obtained from wild-type (WT) rib cartilage and TG or WT epiphyseal cartilage. CTS applied to primary cultures of mock-transfected rib chondrocytes from WT cartilage and WT epiphyseal cartilage induced expression of Col1a1, ColXa1, Mmp-13, and Mmp-9 mRNAs; however, their levels were not affected in CCN2-overexpressing chondrocytes and TG epiphyseal cartilage. In conclusion, cartilage-specific overexpression of CCN2 during the developmental and growth periods reduced age-related changes in articular cartilage. Thus CCN2 may play a role as an anti-aging factor by stabilizing articular cartilage. No potential conflict of interest relevant to this article was reported.

Wiley-Blackwell Acta Medica Okayama 1742-464X 279 19 2012 Roles of heterotypic CCN2/CTGF-CCN3/NOV and homotypic CCN2-CCN2 interactions in expression of the differentiated phenotype of chondrocytes 3597 3584 EN Mitsuhiro Hoshijima Takako Hattori Eriko Aoyama Takashi Nishida Takashi Yamashiro Masaharu Takigawa To identify proteins that regulate CCN2 activity, we carried out GAL4-based yeast two-hybrid screening with a cDNA library derived from a chondrocytic cell line, HCS-2/8. CCN2/CTGF and CCN3/NOV polypeptides were picked up as CCN2-binding proteins, and CCN2CCN2 and CCN2CCN3 binding domains were identified. Direct binding between CCN2 and CCN3 was confirmed by coimmunoprecipitation in vitro and in vivo and surface plasmon resonance, and the calculated dissociation constants (Kd) were 1.17 x 10-9 m for CCN2 and CCN2, and 1.95 x 10-9 m for CCN2 and CCN3. Ectopically overexpressed green fluorescent proteinCCN2 and HaloCCN3 in COS7 cells colocalized, as determined by direct fluorescence analysis. We present evidence that CCN2CCN3 interactions modulated CCN2 activity such as enhancement of ACAN and col2a1 expression. Curiously, CCN2 enhanced, whereas CCN3 inhibited, the expression of aggrecan and col2a1 mRNA in HCS-2/8 cells, and combined treatment with CCN2 and CCN3 abolished the inhibitory effect of CCN3. These effects were neutralized with an antibody against the von Willebrand factor type C domain of CCN2 (11H3). This antibody diminished the binding between CCN2 and CCN2, but enhanced that between CCN3 and CCN2. Our results suggest that CCN2 could form homotypic and heterotypic dimers with CCN2 and CCN3, respectively. Strengthening the binding between CCN2 and CCN3 with the 11H3 antibody had an enhancing effect on aggrecan expression in chondrocytes, suggesting that CCN2 had an antagonizing effect by binding to CCN3. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2000 軟骨由来の慢性関節リウマチ関連抗原RA-A47に関する研究 EN No potential conflict of interest relevant to this article was reported.