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Introduction: Professional dancers are committed to dancing despite their injuries and mood changes. Therefore, dancers’ balance ability should be evaluated as an objective indicator of the quality of their dance/dancing ability. Objective: We aimed to examine the relationship between the balance ability of professional ballet dancers and their psychological traits and states by serotonin polymorphism, using pressure and center of gravity sensors. Methods: Five female professional dancers participated in this three-month longitudinal pilot study. The dancers’ stress status was assessed each month on three conditional days to gauge stress conditions. Before and after their standard warm-up exercises, the dancers’ center of gravity was assessed while standing and posing in ballet-specific positions, and psychological questionnaire surveys were conducted to assess the level of anxiety and objective stress. After all observations were completed, serotonin polymorphism was analyzed as one of the psychological traits. Results: All participants possessed the s/s-type (short type) serotonin transporter gene promoter polymorphism, indicating high sensitivity to stress. Their average trait anxiety score was 50.80±8.47. However, all participants were able to be calm, had no injuries, and maintained a stable center of gravity throughout the study period. Conclusion: Throughout the study, from ordinary practice to the time of the approaching ballet performance, the participants maintained stable balance ability regardless of their psychological traits and states of mind. It is unlikely that reactions to stress and psychological traits affected professional dancers’ physicality. Thus, continuous assessment of the balance between mental and physical aspects enhances performance management.

Bone is an important tissue which is a structural body component, carrying out the roles of mechanical stress response and organ/tissue protection [...]

Objectives JDM is an inflammatory myopathy characterized by prominent vasculopathy. AECAs are frequently detected in inflammatory and autoimmune diseases. We sought to determine whether AECAs correlate with clinical features of JDM, and thus serve as biomarkers to guide therapy or predict outcome. Methods Plasma samples from 63 patients with JDM, 49 patients with polyarticular JIA and 40 juvenile healthy controls were used to detect anti-heat shock cognate 71 kDa protein (HSC70) autoantibodies, a newly identified AECA, in ELISA assays. Clinical features were compared between JDM patients with and without anti-HSC70 autoantibodies. Results Anti-HSC70 autoantibodies were detected in 35% of patients with JDM, in 0% of patients with JIA (P Conclusion Anti-HCS70 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies correlating with disease severity.

The sirtuin family is nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylases that control the acetylation of protein and regulate cellular metabolism. Sirtuins may have two important roles: “regulation of cellular metabolism” and “response to cellular stresses (stress tolerance),” that are associated with the pathogenesis and pathophysiology of a variety of diseases. To further understand the involvement of sirtuins in the “cellular metabolism” and “stress tolerance” is conducive to new insights into the pathophysiology and the development of novel therapies for a variety of diseases. In the chapter, the review features the critical important roles of sirtuins in the cellular metabolism and response to cellular stresses in bone and joint diseases.

Endothelin 1 (ET-1), mainly produced from vascular endothelial cells, induces vasoconstriction in physiological conditions. The endothelin receptor antagonist is among the most effective agents for pulmonary hypertension. However, little is known about the production source of ET-1 in inflammation and immunity. Here, we studied whether T cell-mediated ET-1 production system exists and operates independent of the production system in vascular endothelial cells. ET-1 production was readily detectable in the culture supernatant of human PBMCs and murine spleen cells stimulated with anti-CD3 antibody. Immunocytostaining showed that ET-1-producing cells emerged only in PBMCs stimulated with anti-CD3 antibody. Using the Transwell system, both murine and human monocytes sorted with magnetic beads in the inner chamber produced ET-1 when T cells were activated with antigen or anti-CD3 antibody in the outer chamber. This ET-1 production was inhibited by anti-IFN-γ and/or TNF-α antibody. Furthermore, monocytes purified from ETflox/flox;Tie2-Cre( + ) mice, which conditionally lack ET-1 in hematopoietic stem cells and vascular endothelial cells, did not produce ET-1 even when stimulated by antigen-specific T cell activation. This study demonstrates the existence of an immune-mediated ET-1 production induced by T cells upon activation through IFN-γ and TNF-α.

Mechanical stress is an important factor affecting bone tissue homeostasis. We focused on the interactions among mechanical stress, glucose uptake via glucose transporter 1 (Glut1), and the cellular energy sensor sirtuin 1 (SIRT1) in osteoblast energy metabolism, since it has been recognized that SIRT1, an NAD+-dependent deacetylase, may function as a master regulator of the mechanical stress response as well as of cellular energy metabolism (glucose metabolism). In addition, it has already been demonstrated that SIRT1 regulates the activity of the osteogenic transcription factor runt-related transcription factor 2 (Runx2). The effects of mechanical loading on cellular activities and the expressions of Glut1, SIRT1, and Runx2 were evaluated in osteoblasts and chondrocytes in a 3D cell–collagen sponge construct. Compressive mechanical loading increased osteoblast activity. Mechanical loading also significantly increased the expression of Glut1, significantly decreased the expression of SIRT1, and significantly increased the expression of Runx2 in osteoblasts in comparison with non-loaded osteoblasts. Incubation with a Glut1 inhibitor blocked mechanical stress-induced changes in SIRT1 and Runx2 in osteoblasts. In contrast with osteoblasts, the expressions of Glut1, SIRT1, and Runx2 in chondrocytes were not affected by loading. Our present study indicated that mechanical stress induced the upregulation of Glut1 following the downregulation of SIRT1 and the upregulation of Runx2 in osteoblasts but not in chondrocytes. Since SIRT1 is known to negatively regulate Runx2 activity, a mechanical stress-induced downregulation of SIRT1 may lead to the upregulation of Runx2, resulting in osteoblast differentiation. Incubation with a Glut1 inhibitor the blocked mechanical stress-induced downregulation of SIRT1 following the upregulation of Runx2, suggesting that Glut1 is necessary to mediate the responses of SIRT1 and Runx2 to mechanical loading in osteoblasts.

Osteoarthritis (OA) is one of the most common age-related degenerative joint disorders. In addition to aging, various life-style-related factors, such as obesity and overuse of joints, have been recognized as major risk factors for OA. It has been revealed that mechanical force acting on articular cartilage induces chondrocytes to produce excess amounts of reactive oxygen species (ROS), which are known to be an OA-related catabolic factor. In addition, it has been reported that mechanical stress-induced ROS directly damage chondrocyte DNA, resulting in the downregulation of cellular activity and induction of apoptosis in osteoarthritic chondrocytes. Notably, molecular events associated with DNA oxidative damage influence the regulation of chondrocyte activity and cellular viability, supporting the notion that mechanical stress-induced oxidization of chondrocyte DNA participates in the pathogenesis of OA. Here, we review accumulating evidence supporting the involvement of mechanical and oxidative stresses in cartilage homeostasis and the pathogenesis of OA.

Takanori Kumai,1 Naoko Yui,1 Kanaka Yatabe,1 Chizuko Sasaki,2 Ryoji Fujii,3 Mitsuko Takenaga,3 Hiroto Fujiya,1 Hisateru Niki,4 Kazuo Yudoh3 1Department of Sports Medicine, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8511, Japan; 2Institute for Ultrastructural Morphology, St Marianna University Graduate School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan; 3Department of Frontier Medicine, Institute of Medical Science, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan; 4Department of Orthopaedic Surgery, St Marianna University School of Medicine, Miyamae-ku, Kawasaki 216-8512, Japan Purpose: We previously created a self-assembled cartilage-like complex invitro from only three cartilage components, hyaluronic acid (HA), aggrecan (AG) and type II collagen, without other materials such as cross-linking agents. Based on this self-organized AG/HA/collagen complex, we have created three novel types of biphasic cartilage and bone-like scaffolds combined with hydroxyapatite (HAP) for osteochondral tissue engineering. These scaffolds have been developed from self-assembled cartilage component molecules and HAP at the nanometer scale by manipulating the intermolecular relations. Patients and methods: The surface structure of each self-organized biphasic cartilage and bone-like scaffold was evaluated by scanning electron microscopy, whereas the viscoelasticity was also analyzed invitro. Three types of artificial cartilage–HAP conjugates were implanted into an osteochondral defect in rat knee joints, and bone and cartilage tissues of the implanted site were examined 4 and 8 weeks after implantation. The tissues were examined histopathologically to evaluate the effects of the implantation on the articular cartilage and subchondral bone tissues. Results: Our invitro and invivo data reveal that the self-organized biphasic cartilage and bone-like scaffold conjugated with HAP are superior to the scaffold with no HAP in both cartilage regeneration and subchondral bone regeneration. Conclusion: Our present study indicates that the self-organized biphasic cartilage and bone-like scaffold, which is conjugated with an HAP layer, may have potential not only to repair articular cartilage defects but also to ameliorate the degeneration of subchondral bone in the diseases with osteochondral defect. Keywords: cartilage tissue engineering, subchondral bone, articular cartilage, osteoarthritis, self assembly, hydroxyapatite

The effect of prostaglandin E1 (PGE1) encapsulated in nanoparticles (Nano PGE1) on motor dysfunction and muscle atrophy induced by sciatic nerve injury (SNI) was investigated in rats, and was compared with PGE1 encapsulated in lipid microspheres (Lipo PGE1) or PGE1 clathrated in cyclodextrin (PGE1-CD). The hind limb muscle weight ratio decreased until 2 weeks after SNI. All 3 PGE1 formulations significantly improved SNI-induced motor dysfunction. Nano PGE1 significantly promoted recovery from muscle atrophy at 2 and 3 weeks after SNI. Lipo PGE1 was also effective, but multiple doses were required. Compared with the SNI control group, the Nano PGE1 group showed upregulation of vascular endothelial growth factor (VEGF) and agrin expression in the injured sciatic nerve and atrophic muscles. Nano PGE1 accumulated prominently at the site of nerve injury and persisted for longer than Lipo PGE1 or PGE1-CD. Expression of all EP receptors was detected in the normal sciatic nerve, and EP2 expression increased after SNI. Finally, Nano PGE1 promoted ERK1/2 and Akt phosphorylation. These findings suggest that PGE1 released from nanoparticles accumulates at sites of nerve injury and increases VEGF production by augmenting ERK1/2 phosphorylation via EP receptor signaling, thus promoting tissue repair and regeneration.

This study was performed to elucidate the molecular function of the synoviocyte proliferation-associated in collagen-induced arthritis (CIA) 1/serum amyloid A-like 1 (SPACIA1/SAAL1) in mice CIA, an animal model of rheumatoid arthritis (RA), and human RA-synovial fibroblasts (RASFs). SPACIA1/SAAL1-deficient mice were generated and used to create mouse models of CIA in mild or severe disease conditions. Cell cycle-related genes, whose expression levels were affected by SPACIA1/SAAL1 small interfering RNA (siRNA), were screened. Transcriptional and post-transcriptional effects of SPACIA1/SAAL1 siRNA on cyclin-dependent kinase (cdk) 6 gene expression were investigated in human RASFs. SPACIA1/SAAL1-deficient mice showed later onset and slower progression of CIA than wild-type mice in severe disease conditions, but not in mild conditions. Expression levels of cdk6, but not cdk4, which are D-type cyclin partners, were downregulated by SPACIA1/SAAL1 siRNA at the post-transcriptional level. The exacerbation of CIA depends on SPACIA1/SAAL1 expression, although CIA also progresses slowly in the absence of SPACIA1/SAAL1. The CDK6, expression of which is up-regulated by the SPACIA1/SAAL1 expression, might be a critical factor in the exacerbation of CIA.

Objective Although generally classified within the group of inflammatory myopathies, JDM displays many pathological features of vasculitis. Previous work has shown that AECA are abundant in other forms of vasculitis. We therefore investigated whether such antibodies might also be detected in JDM. Methods We screened plasma from children with JDM for the presence of AECA by western blotting and 2D gel electrophoresis (2DE) using proteins extracted from human aortic endothelial cells as the substrate. We performed mass spectrometry to identify candidate antigens from 2DE gels and used ELISA to confirm the presence of specific antibodies. Results We identified 22 candidate target autoantigens for AECA probed with JDM plasma. Interestingly, 17 of these 22 target antigens were proteins associated with antigen processing and protein trafficking. ELISA confirmed the presence of antibodies to heat shock cognate 71 kDa protein in JDM plasma, particularly in children with active, untreated disease. Conclusion Children with JDM express antibodies to autoantigens in endothelial cells. The clinical and pathological significance of such autoantibodies require further investigation.

The aim of this study was to determine the prognostic characteristics of patients with relapsing polychondritis (RP) accompanying cutaneous manifestations in Japan. We analyzed a cohort of 239 patients with RP in view of cutaneous and extracutaneous complications. Thirty three cases (14%) developed cutaneous manifestations and 23 cases had both cutaneous and extracutaneous manifestations. Five RP patients developed myelodysplastic syndrome (MDS) and all of the five patients had cutaneous manifestations, including Sweet's syndrome. Only one patient died of MDS among the five patients, suggesting rather better prognosis as compared with ordinary MDS. Five RP patients developed Behcet's disease and all the five patients had cutaneous manifestations. Death rate of the RP patients with cutaneous manifestations (15%) was slightly higher than that of whole Japanese RP patient cohort (9.2%). RP patients with cutaneous manifestations had a slightly higher death rate, than those without cutaneous manifestations. MDS of RP patients had a rather better prognostic impact in Japan. Further studies are needed to elucidate the pathophysiology of RP, which brings about development of extracutaneous manifestations, especially MDS and Behcet's disease.

Objective: To study a comprehensive proteomic analysis of celecoxib in oseteoarthritis (OA) chondrocytes. Methods: OA chondrocytes were stimulated with celecoxib, IL-1β and IL-1β together with celecoxib. Proteins were extracted from the cells and subjected to 2-dimensional differential image gel electrophoresis (2D-DIGE). Proteins of interest were identified by mass spectrometry. Results: Eighty-six protein spots showed significantly different intensities with each reagent or reagent combination. AAA+ protein, HSP47/Serpin, cAMP-dependent protein kinase type II-beta regulatory subunit, alpha-actin-4 and tubulin decreased with the addition of celecoxib, while apolipoprotein A-V, glutamate carboxipeptide 2, mitochondrial stress-70 protein, sorting nexin-9 and GRP78 increased with the addition of celecoxib. GRP78 is a stress protein and may be chondroprotective. Celecoxib modulated IL-1β stimulated chondrocytes, and CD200R and moesin were identified as such resulting proteins. Conclusion: Protein profiles of OA chondrocytes changed after administration of celecoxib. Further investigation is needed to elucidate the function of each protein in OA chondrocytes.

Relapsing polychondritis (RP) is a multisystem disorder characterized by recurrent inflammation and destruction of cartilage. The aim of this study is to assess the clinical characteristics of patients with RP in Japan, which remain unclear. A survey was sent to 395 experienced clinicians who worked in Japanese major institutions. The questionnaire was designed to assess patients' profiles, clinical features, diagnosis, treatments and present complications. The response rate was 30.6% and 239 RP patient data were collected. The average age of onset diagnosis was 52.7 years (range, 3-97) and the male-to-female ratio was 1.1:1. Clinical features of patients with RP in Japan were similar to previous studies. Airway and cardiac involvement, both of which were potentially serious complications of RP, were observed in 119 (49.8%) and 17 patients (7.1 %), respectively. Four patients (1.7%) had myelodysplasia. In addition to oral prednisolone (91.6%), patients received methotrexate (19.7%), cyclophosphamide (12.6%) and cyclosporine (8.4%) with clinical response rates of 64.0%, 66.7% and 73.7%, respectively. 42 patients (17.6%) required and underwent tracheotomy, including 12 patients (5.0%) who were treated with prednisolone only. 22 patients (9.2%) underwent stent placement and/or tracheotomy. The overall mortality rate was 9.0% (22 patients) and respiratory failure and pulmonary infection were the leading causes of death in patients with RP. Airway involvement of RP was fundamentally progressive and required frequent clinical checks and appropriate intervention with administration of both prednisolone and immunosuppressant. Cardiac involvement of RP was less common in Japan as compared with that in Western countries. Rec.11/22/2013, Acc.2/11/2014, pp149-156

We aimed to identify a serum biomarker for evaluating the disease activity of relapsing polychondritis (RP). We measured and compared serum levels of 28 biomarkers potentially associated with this disease, including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), high-sensitivity C-reactive protein (hs-CRP), and cartilage oligomeric matrix protein (COMP), in 15 RP patients and 16 healthy donors (HDs). We divided the 15 RP patients into active RP (n = 8) and inactive RP (n = 7) groups, depending on the extent of the disease, and compared candidate markers between groups. The localization of membrane-bound TREM-1 in the affected tissue was examined by immunohistochemistry. Serum levels of sTREM-1, interferon-γ, chemokine (C–C motif) ligand 4, vascular endothelial growth factor, and matrix metalloproteinases-3 were significantly higher in RP patients than HDs. Among these markers, sTREM-1 had the highest sensitivity and specificity (86.7 and 86.7 %, respectively). Furthermore, the serum level of sTREM-1 was significantly higher in active RP patients than inactive RP patients (p = 0.0403), but this was not true for hs-CRP or COMP. TREM-1 was expressed on endothelial cells in RP lesions. The serum level of sTREM-1 may be a useful marker of disease activity in RP.

Human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a rare neurodegenerative disease characterized by chronic inflammation in the spinal cord. We hypothesized that a positive feedback loop driven by chemokines may be responsible for the chronic inflammation in HAM/TSP. We aimed to determine the identity of these chemokines, where they are produced, and how they drive chronic inflammation in HAM/TSP. We found that patients with HAM/TSP have extraordinarily high levels of the chemokine CXCL10 (also known as IP-10) and an abundance of cells expressing the CXCL10-binding receptor CXCR3 in the cerebrospinal fluid. Histological analysis revealed that astrocytes are the main producers of CXCL10 in the spinal cords of patients with HAM/TSP. Co-culture of human astrocytoma cells with CD4+ T cells from patients with HAM/TSP revealed that astrocytes produce CXCL10 in response to IFN-γ secreted by CD4+ T cells. Chemotaxis assays results suggest that CXCL10 induces migration of peripheral blood mononuclear cells to the central nervous system and that anti-CXCL10 neutralizing antibody can disrupt this migration. In short, we inferred that human T-lymphotropic virus type 1-infected cells in the central nervous system produce IFN-γ that induces astrocytes to secrete CXCL10, which recruits more infected cells to the area via CXCR3, constituting a T helper type 1-centric positive feedback loop that results in chronic inflammation.

To clarify how the osteoarthritis (OA)-induced catabolic factor interleukin (IL)-1β affects chondrocyte energy metabolism, and especially to define the downstream pathway linking nicotinamide adenine dinucleotide (NAD)- dependent deacetylase Sirtuin-1 (Sirt-1) to energy metabolism in OA chondrocytes. Human chondrocytes were isolated from articular cartilage samples of patients with OA. The level of energy metabolism of OA chondrocytes was evaluated by monitoring the activity of the energy metabolic sensor, adenosine monophosphate-activated protein kinase (AMPK) and the level of production of adenosine triphosphate (ATP) in chondrocytes in the presence or absence of t IL-1β (10 ng/mL). Effects of IL-1β on anabolic and catabolic activities of chondrocytes were analyzed by the levels of production of proteoglycan and matrix metalloproteinase (MMP)-13, respectively. Experiments involving pre-treatment with Sirt-1 inhibitor were also performed to investigate the underlying regulatory mechanism linking Sirt-1 to chondrocyte energy metabolism. IL-1β significantly inhibited the activity of AMPK and production of ATP in OA chondrocytes. The energy metabolism disruption mediated by IL-1β was further decreased by pretreatment with Sirt-1 inhibitor in OA chondrocytes. Treatment with IL-1β significantly decreased the level of proteoglycan production and significantly increased the level of MMP-13 secretion by chondrocytes. These chondrocyte activities were also reduced by pre-treatment with the Sirt-1 inhibitor in OA chondrocytes. IL-1β inhibits the AMPK - ATP energy metabolic pathway in OA chondrocytes. Our findings also suggest that Sirt-1 activity is involved in anabolic and catabolic cellular activities and that Sirt-1 modulates ATP production through functional regulation of the energy sensor AMPK in chondrocytes.

Author(s): Fotis, Lampros; Shaikh, Nur; Baszis, Kevin; French, Anthony; Tarr, Phillip; Grevich, Sriharsha; Lee, Peggy; Ringold, Sarah; Leroux, Brian; Leahey, Hannah; Yuasa, Megan; Foster, Jessica; Sokolove, Jeremy; Lahey, Lauren; Robinson, William; Newsom, Joshua; Stevens, Anne; Karasawa, Rie; Tamaki, Mayumi; Tanaka, Megumi; Sato, Toshiko; Yudoh, Kazuo; Jarvis, James N; Moncrieffe, Halima; Bennett, Mark F; Tsoras, Monica; Luyrink, Lorie; Xu, Huan; Prahalad, Sampath; Morris, Paula; Dare, Jason; Nigrovic, Peter A; Rosenkranz, Margalit; Becker, Mara; O’Neil, Kathleen M; Griffin, Thomas; Lovell, Daniel J; Grom, Alexei A; Medvedovic, Mario; Thompson, Susan D; Zhu, Lisha; Jiang, Kaiyu; Wong, Laiping; Buck, Michael J; Chen, Yanmin; Moncrieffe, Halima; Brungs, Laura; Liu, Tao; Wang, Ting; Jarvis, James N; Alsaeid, Khaled; Alfailakawi, Jasim; Alenezi, Hamid; Alsaeed, Hazim; Beukelman, Tim; Natter, Marc; Ilowite, Norm; Mieszkalski, Kelly; Burrell, Grendel; Best, Brian; Bristow, Helen; Carr, Shannon; Dennos, Anne; Kaufmann, Rachel; Kimura, Yukiko; Schanberg, Laura; Blier, Peter R; Boneparth, Alexis; Wenderfer, Scott E; Moorthy, L Nandini; Radhakrishna, Suhas M; Sagcal-Gironella, Anna Carmela P; von Scheven, Emily; Gedik, Kader Cetin; Siddique, Salma; Aguiar, Cassyanne L; Erkan, Doruk; Cohen, Ezra; Lee, Yvonne; Dossett, Michelle; Mehta, Darshan; Davis, Roger; Gilbert, Mileka; Goilav, Beatrice; Meidan, Esra

Aging is one of the major pathologic factors associated with osteoarthritis (OA). Recently, numerous reports have demonstrated the impact of sirtuin-1 (Sirt1), which is the NAD-dependent deacetylase, on human aging. It has been demonstrated that Sirt1 induces osteogenic and chondrogenic differentiation of mesenchymal stem cells. However, the role of Sirt1 in the OA chondrocytes still remains unknown. We postulated that Sirt1 regulates a hypertrophic chondrocyte lineage and degeneration of articular cartilage through the activation of osteogenic transcriptional activator Runx2 and matrix metalloproteinase (MMP)-13 in OA chondrocytes. To verify whether sirtuin-1 (Sirt1) regulates chondrocyte activity in OA, we studied expressions of Sirt1, Runx2 and production of MMP-13, and their associations in human OA chondrocytes. The expression of Sirt1 was ubiquitously observed in osteoarthritic chondrocytes; in contrast, Runx2 expressed in the osteophyte region in patients with OA and OA model mice. OA relating catabolic factor IL-1βincreased the expression of Runx2 in OA chondrocytes. OA chondrocytes, which were pretreated with Sirt1 inhibitor, inhibited the IL-1β-induced expression of Runx2 compared to the control. Since the Runx2 is a promotor of MMP-13 expression, Sirt1 inactivation may inhibit the Runx2 expression and the resultant down-regulation of MMP-13 production in chondrocytes. Our findings suggest thatSirt1 may regulate the expression of Runx2, which is the osteogenic transcription factor, and the production of MMP-13 from chondrocytes in OA. Since Sirt1 activity is known to be affected by several stresses, including inflammation and oxidative stress, as well as aging, SIRT may be involved in the development of OA.

Layilin (LAYN), a 55-kDa transmembrane protein with homology to C-type lectins, has been identified as a receptor of hyaluronan (HA). Interestingly, LAYN does not share any sequence homology with CD44, a primary HA receptor. The primary aim of our study was to examine the expression and potential function of LAYN in human articular chondrocytes and synoviocytes. Samples were obtained from patients undergoing joint arthroplasty. Cells were grown in vitro, then stimulated with interleukin (IL)-1β or tumor necrosis factor alpha (TNFα) for 24 h and the expression of LAYN was analyzed. To assess the function of LAYN, we transfected chondrocytes with siRNA against LAYN, treated them with HA and IL-1β, and then analyzed the production of matrix metalloproteinase (MMP)-1 and MMP-13 in the treated chrondrocytes. The results showed that LAYN was constitutively expressed in human articular chondrocytes and synoviocytes and that IL-1β significantly suppressed the expression of LAYN in these cells. HA repressed IL-1β-induced MMP-1 and MMP-13 production in chondrocytes, but this was significantly abrogated in chondrocytes transfected with siRNA against LAYN. Our results show that human chondrocytes express LAYN, a novel HA receptor, and that LAYN may contribute to the regulation of HA functions in the arthritic condition. Further investigation of the HA receptor may lead to the development of novel therapeutics to regulate HA signaling in inflammatory arthritis.

Recently, attention has been drawn to tissue engineering and other novel techniques aimed at reconstruction of the joint. Regarding articular cartilage tissue engineering, three-dimensional materials created in vitro by cultivation of autologous chondrocytes or mesenchymal stem cells with a collagen gel have been implanted to replace defective parts of the articular cartilage in limited cases with the diseases such as trauma or arthritis. However, several passages of chondrocyte culture are required to obtain a sufficient number of cells for tissue engineering. Additionally, several other problems arise including dedifferentiation of chondrocytes during cell culture, which need to be solved from a viewpoint of cellular resources. The purpose of our study is to create a novel biomaterial possessing functions and structures comparable to native hyaline articular cartilage by utilizing the physicochemical properties of the cartilage matrix components themselves, in other words, employing a self-assembly technique instead of using chondrocytes to produce cartilage matrices eventually leading to articular cartilage tissue formation. We verified the conditions and accuracy of the self-organization process and analyzed the resulting micro structure using electron beam microscopy in order to study the technique involved in the self-organization which would be applicable to creation of cartilage-like tissue. We demonstrated that self-assembly of several cartilage components including type II collagen, proteoglycan and hyaluronic acid could construct self-assembled cartilage-like tissues characterized by nano composite structures comparable to human articular cartilage and by low friction coefficients as small as those of native cartilage.

Antibodies to the anti-oxidative peroxiredoxin (Prx) enzymes occur in both systemic autoimmune disease and vasculitis in adulthood. Because increased oxidative stress induces vasculitis in Kawasaki disease (KD), autoimmunity to Prxs in patients with KD was investigated. The presence of antibodies to Prx 1, 2 and 4 was analyzed by ELISA and Western blot. Of 30 patients with KD, 13 (43.3%) possessed antibodies to Prx 2, whereas these antibodies were present in only 1 of 10 patients (10.0%) with sepsis (4 with purulent meningitis and 6 with septicemia). In contrast, antibodies to Prx 1 and 4 were not detected in either group. There was no significant correlation among the titers of the three antibodies. Clinical parameters were compared between anti-Prx 2-positive and -negative patients. The presence of anti-Prx 2 antibodies correlated with a longer period of fever and poor response to high-dose γ-globulin therapy in patients with KD. Anti-Prx 2-positive patients had significantly greater excretion of urinary 8-isoprostaglandin than did anti-Prx 2-negative patients. These results provide the first evidence for an antibody to Prx 2 in patients with KD. They also suggest that this antibody might serve as a marker of disease severity and be involved in the pathophysiology of vasculitis in some patients with KD.

Objective To identify novel genes associated with dysregulated proliferation of activated synovial fibroblasts, which are involved in arthritic joint destruction. Methods We performed transcriptome analysis to identify genes that were up-regulated in the foot joints of mice with collagen-induced arthritis (CIA). The effect of candidate genes on proliferation of synovial fibroblasts was screened using antisense oligodeoxynucleotides and small interfering RNAs (siRNAs). We characterized the expression and function of a novel gene, synoviocyte proliferation–associated in collagen-induced arthritis 1 (SPACIA1)/serum amyloid A–like 1 (SAAL1) using antibodies and siRNA and established transgenic mice to examine the effect of SPACIA1/SAAL1 overexpression in CIA. Results Human and mouse SPACIA1/SAAL1 encoded 474 amino acid proteins that shared 80% homology. SPACIA1/SAAL1 was primarily expressed in the nucleus of rheumatoid arthritis (RA) synovial fibroblasts and was highly expressed in the hyperplastic lining of inflamed synovium. In addition, its expression level in RA- or osteoarthritis (OA)–affected synovial tissue was positively correlated with the thickness of the synovial lining. Furthermore, SPACIA1/SAAL1 siRNA inhibited the proliferation of synovial fibroblasts, especially tumor necrosis factor α–induced synovial fibroblasts, by blocking entry into the S phase without inducing apoptosis. Finally, transgenic mice overexpressing SPACIA1/SAAL1 exhibited early onset and rapid progression of CIA. Conclusion These results suggest that SPACIA1/SAAL1 is necessary for abnormal proliferation of synovial fibroblasts and its overexpression is associated with the progression of synovitis in mice and humans. Thus, therapy targeting SPACIA1/SAAL1 might have potential as an inhibitor of synovial proliferation in RA and/or OA.

Objective To identify novel proteins involved in the pathogenesis of rheumatoid arthritis (RA) and to characterise the identified proteins based on pathogenic and therapeutic aspects. Methods The authors applied differential phosphoproteomic analysis to articular synoviocytes between RA and osteoarthritis (OA) to identify proteins differently phosphorylated between RA and OA. Focusing on annexin VII (Anx7), one of the highly phosphorylated proteins in RA, the authors prepared Anx7 -transgenic C57BL/6 ( Anx7 -Tg-B6) mice to evaluate their susceptibility to collagen-induced arthritis (CIA). In addition, the authors examined the effect of anti-Anx7 antibodies (Abs) on CIA and serum levels of cytokines in wild-type DBA/1J mice, which are known to be susceptible to CIA, and in Anx7 -Tg-B6 mice. In vitro, the authors examined the effect of the Anx7 knockdown by small interfering RNA on the secretion of cytokines in rheumatoid synoviocytes and the human synovial sarcoma cell line SW982. Results The Anx7 transgene altered the CIA-resistant B6 mice to CIA-susceptible ones. The Abs treatment suppressed CIA even in the wild-type DBA/1J mice. The serum levels of cytokines including interleukin 6 (IL-6) and TNFα were not altered by the Abs treatment in vivo. On the other hand, the knockdown of Anx7 by small interfering RNA caused downregulation of IL-8 secretion in vitro. Conclusions These results indicate that Anx7 participates in the pathogenesis of RA partly through the secretion of IL-8. The study data have demonstrated the pathogenic roles and therapeutic significance of Anx7 in RA for the first time.

Recent reports have shown that statin (HMG-CoA reductase inhibitors) may have the potential to inhibit inflammatory arthritis. More recently, the idea that chondrocyte aging is closely associated with the progression of cartilage degeneration has been promulgated. Here, we demonstrate the potential of statin as protective agents against chondrocyte aging and degeneration of articular cartilage during the progression of osteoarthritis (OA), both in vitro and in vivo. The OA-related catabolic factor, IL-1β induced marked downregulation of cellular activity, expression of a senescent biomarker, specific senescence-associated β-galactosidase activity and shortening of the cellular lifespan in chondrocytes. In contrast, treatment with statin inhibited the IL-1β-induced production of cartilage matrix degrading .enzymes (metalloprotease-1 and -13) and cellular senescence in of chondrocytes in vitro. In addition, this statin accelerated the production of cartilage matrix proteoglycan in chondrocytes. The in vivo study was performed on the STR/OrtCrlj mouse, an experimental model which spontaneously develops an osteoarthritic process. In this mouse model, treatment with statin significantly reduced the degeneration of articular cartilage, while the control knee joints showed progressive cartilage degeneration over time. These findings suggest that statin may have the potential to prevent the catabolic stress-induced chondrocyte disability and aging observed in articular cartilage. Our results indicate that statin are potential therapeutic agents for protection of articular cartilage against the progression of OA.

We analyzed serum short peptides comprehensively to know whether they were useful to characterize IgA nephropathy (IgAN). Serum samples from 26 patients with untreated IgAN and 25 healthy donors were tested. Short peptides with molecular weights of approximately 7 kDa, purified from the serum samples by magnetic-beads-based weak cation exchange, were detected by mass spectrometry. Then the peptide peaks detected were subjected to the multivariate data analysis by SIMCA-P+ containing principal component analysis (PCA) and orthogonal partial-least-squares-discriminate analysis (OPLS-DA). A total of 92 peptide peaks were detected in the tested serum samples. The OPLS-DA analysis revealed that the profile of all the peptide peak intensities discriminated the IgAN group and the healthy group completely with a high R2 value (0.919) and a high Q2 value (0.861). Further, the profile of only five peptide peaks was found to discriminate the two groups. By tandem mass spectrometry and database searching, three of the five peptides which increased in the IgAN group were identified as fragments of fibrinogen alpha chain, and the two peptides which increased in the healthy group were identified as fragments of complement C3f and kininogen-1 light chain. Taken together, the profile of the serum short peptides would be useful to discriminate IgAN and healthy conditions. Further, the five peptides may be candidate serum markers for IgAN and may be related to pathogenesis of IgA.

Recently, attention has been drawn to the involvement of cellular ageing in the pathogenesis of bone and joint diseases. We reviewed the mechanism underlying degeneration of bone and cartilage tissues, from a viewpoint of the senescence of cells composing the joints. We demonstrated not only the mechanism controlling ageing but also the development of new methods of treatment and prophylactic measures for diseases affecting bone and joint tissues in the future.