Molecular transplantation: delivery of membranous proteins onto live cells.
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Animals↗
Biomedical subjects
Tomohiro Kato
Publications and source records attributed to Tomohiro Kato.
Potential involvement of oxidative stress in cartilage senescence and development of osteoarthritis: oxidative stress induces chondrocyte telomere instability and downregulation of chondrocyte function.
Oxidative stress leads to increased risk for osteoarthritis (OA) but the precise mechanism remains unclear. We undertook this study to clarify the impact of oxidative stress on the progression of OA from the viewpoint of oxygen free radical induced genomic instability, including telomere instability and resulting replicative senescence and dysfunction in human chondrocytes. Human chondrocytes and articular cartilage explants were isolated from knee joints of patients undergoing arthroplastic knee surgery for OA. Oxidative damage and antioxidative capacity in OA cartilage were investigated in donor-matched pairs of intact and degenerated regions of tissue isolated from the same cartilage explants. The results were histologically confirmed by immunohistochemistry for nitrotyrosine, which is considered to be a maker of oxidative damage. Under treatment with reactive oxygen species (ROS; 0.1 micromol/l H2O2) or an antioxidative agent (ascorbic acid: 100.0 micromol/l), cellular replicative potential, telomere instability and production of glycosaminoglycan (GAG) were assessed in cultured chondrocytes. In tissue cultures of articular cartilage explants, the presence of oxidative damage, chondrocyte telomere length and loss of GAG to the medium were analyzed in the presence or absence of ROS or ascorbic acid. Lower antioxidative capacity and stronger staining of nitrotyrosine were observed in the degenerating regions of OA cartilages as compared with the intact regions from same explants. Immunostaining for nitrotyrosine correlated with the severity of histological changes to OA cartilage, suggesting a correlation between oxidative damage and articular cartilage degeneration. During continuous culture of chondrocytes, telomere length, replicative capacity and GAG production were decreased by treatment with ROS. In contrast, treatment with an antioxidative agent resulted in a tendency to elongate telomere length and replicative lifespan in cultured chondrocytes. In tissue cultures of cartilage explants, nitrotyrosine staining, chondrocyte telomere length and GAG remaining in the cartilage tissue were lower in ROS-treated cartilages than in control groups, whereas the antioxidative agent treated group exhibited a tendency to maintain the chondrocyte telomere length and proteoglycan remaining in the cartilage explants, suggesting that oxidative stress induces chondrocyte telomere instability and catabolic changes in cartilage matrix structure and composition. Our findings clearly show that the presence of oxidative stress induces telomere genomic instability, replicative senescence and dysfunction of chondrocytes in OA cartilage, suggesting that oxidative stress, leading to chondrocyte senescence and cartilage ageing, might be responsible for the development of OA. New efforts to prevent the development and progression of OA may include strategies and interventions aimed at reducing oxidative damage in articular cartilage.
Aged↗
Analysis of T cell receptor (TCR) BV-gene clonotypes in NC/Nga mice developing dermatitis resembling human atopic dermatitis.
BACKGROUND: Our previous study showed that T cells in skin lesions of human atopic dermatitis (AD) had oligoclonal accumulation, indicating the involvement of antigen-specific immune reactions at those sites. Recently, NC/Nga mice, which develop skin lesions similar to AD, have been proposed as a model for that disease. OBJECTIVE: To clarify whether NC/Nga mice are suitable as a model for human AD from the viewpoint of their antigen-specific immune responses. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and single strand conformation polymorphism (SSCP) analyses were conducted to detect TCR BV genes of clonally expanded T cells derived from NC/Nga mice at an early phase of the AD-like dermatitis, at a late phase of the dermatitis, and with no AD-like dermatitis. RESULTS: (1) T cells with TCR BV 7, 10 and 17 reside in the skin of NC/Nga mice without the AD-like dermatitis. (2) T cells with these BV genes contain oligoclonal accumulations, however, expanded T cell clonotypes are also detected in the spleen and exist constantly during the course of the AD-like dermatitis. (3) Development of the AD-like dermatitis is associated with additional oligoclonal expansion/accumulation of T cells with TCR BV 2, 4 and 6 genes. (4) Progression of the AD-like dermatitis is associated with further oligoclonal expansion/accumulation of T cells with the TCR BV 14 gene. (5) Some of the expanded TCR clonotypes are common between the individual mice and between early and late phases. CONCLUSIONS: Taking these data together with the previous human AD studies, NC/Nga mice seem to be an appropriate model for human AD.
Animals↗
[Progress in endoscopic diagnosis of stomach cancer].
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Gastroscopy↗
Autoantibodies to peroxiredoxin I and IV in patients with systemic autoimmune diseases.
Anti-oxidative enzymes protect living bodies from various oxidative stresses. In the systemic autoimmune diseases, autoantibodies to oxidized molecules and to anti-oxidative enzymes have been reported. To promote understanding of the relationships between autoimmunity and oxidative stress, we here investigate whether autoimmunity to the anti-oxidative peroxiredoxin (Prxs) enzymes exists in patients with systemic autoimmune diseases. Specifically, we detected autoantibodies to recombinant Prx I and Prx IV respectively by ELISA and western blotting. Next, clinical parameters were compared between the anti-Prx I or IV-positive and-negative patients. We found that 33% of the 92 patients with autoimmune diseases tested possessed autoantibodies to Prx I (57% in systemic lupus erythematosus (SLE), 19% in rheumatoid arthritis (RA), 5% in Behçet disease, and 46% in primary vasculitis syndrome). In contrast, autoantibodies to Prx IV were detected in only 17% of the same patients. No significant correlation was found between occurrence of the two autoantibodies. Clinically, possession of anti-Prx I autoantibodies correlated with lower serum levels of CH50, C3, and C4. Taken together, our data demonstrate the existence of autoantibodies to Prxs for the first time. The autoantibodies to Prx I may be involved in the pathophysiology of systemic autoimmune diseases such as SLE and vasculitis.
Arthritis, Rheumatoid↗
Normal liver regeneration and liver cell apoptosis after partial hepatectomy in tumor necrosis factor-alpha-deficient mice.
AIMS/BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) is known as a proinflammatory cytokine that has been implicated as a contributing factor in a number of disease processes. TNF-alpha also influences liver repair following hepatotoxic damage, and regeneration following partial hepatectomy (PH). The aim of this study was to assess the mechanism by which TNF-alpha influences liver cell apoptosis and regeneration following PH in TNF-alpha-deficient (TNF-alpha(-/-)) mice. METHODS: PH was performed in wild mice and TNF-alpha(-/-) mice. RESULTS: In both groups, serum alanine aminotransferase and serum total bilirubin levels comparably peaked at 6 and 48 h after PH, respectively. No differences were observed in hepatocyte proliferation, as determined by mitotic and the proliferating cell nuclear antigen labeling indices, between TNF-alpha(+/+) and TNF-alpha(-/-) mice. Few terminal deoxynucleotidyl transferase nick end-labeling-positive hepatocytes were seen in either type of mice. Nuclear factor-kappa B DNA binding activity in the remaining liver of TNF-alpha(-/-) mice after PH was similar to that of control mice. Ribonuclease protection assay showed that transforming growth factor beta1 mRNA was up-regulated comparably in the livers of the two groups, and that other cytokines were hardly seen in either. Interleukin-6/ signal transducer and activator of transcription-3-dependent pathway was not affected in TNF-alpha(-/-) mice. CONCLUSIONS: These findings suggest that TNF-alpha has little influence on liver regeneration and liver cell apoptosis after PH in mice.
Alanine Transaminase↗
Suppressive effects of hyaluronan on MMP-1 and RANTES production from chondrocytes.
The purpose of the study was to examine the effects of hyaluronan (HA) on human chondrocytes in terms of production of MMP-1 and RANTES. Chondrocytes were obtained from patients with osteoarthritis (OA) or femoral neck fracture (control). Chondrocytes in monolayer culture were treated with various molecular weights (1.2, 50, 800 and 1,900 kD) of HA and then stimulated with IL-1beta. Production and expression of MMP-1 and RANTES were quantified by ELISA and real-time polymerase chain reaction (PCR). The response was blocked by anti-CD44 antibody. Production of MMP-1 was significantly suppressed by both 800- and 1,900-kD HA, while production of RANTES was suppressed by 1,900-kD HA. Expression of MMP-1 and RANTES mRNA was inhibited by 1,900-kD HA. Suppressive effects of HA on production of MMP-1 were canceled by treatment of anti-CD44 antibody. Higher CD44 expression was found in OA chondrocytes than in those of control. High-molecular-weight HA suppressed MMP-1 and RANTES production, mediated partly by CD44-HA interaction.
Adjuvants, Immunologic↗
The prevalence of autoantibodies against cartilage intermediate layer protein, YKL-39, osteopontin, and cyclic citrullinated peptide in patients with early-stage knee osteoarthritis: evidence of a variety of autoimmune processes.
We studied arthritis-related autoantibodies in 136 patients with knee osteoarthritis (OA) and 67 age- and sex-matched healthy individuals in the Shanghai District of China. Serum antibody titers for recombinant fusion proteins of cartilage intermediate layer protein (CILP) and YKL-39 were analyzed using enzyme-linked immunosorbent assay (ELISA) and Western blot. Serum antibody titers against recombinant osteopontin (OPN) and cyclic citrullinated peptide (CCP) antibodies were measured also using ELISA. Anti-CILP antibodies were detected in 25/136 OA patients but only 1/67 controls. Anti-YKL-39, anti-OPN, and anti-CCP antibodies were detected in 9/136, 11/136, and 7/136 of the OA patients, respectively, and 0/67 controls. There was rarely overlap of these antibodies in a single patient, suggesting distinct antigen specificity in each case. The antibodies were detected in patients with OA of grades II and III but not grade IV. The prevalence of autoantibodies to various arthritis-related proteins in early-stage knee OA supports the involvement of a specific immune response in initial cartilage degeneration in OA.
Adipokines↗
A potential role of 15-deoxy-delta(12,14)-prostaglandin J2 for induction of human articular chondrocyte apoptosis in arthritis.
The cyclopentenone prostaglandin (PG) J2 is formed within the cyclopentenone ring of the endogenous prostaglandin PG D2 by a nonenzymatic reaction. The PG J family is involved in mediating various biological effects including the regulation of cell cycle progression and inflammatory responses. Here we demonstrate the potential role of 15-deoxy-Delta(12,14)-prostaglandin J2 (15d-PG J2) in human articular chondrocyte apoptosis. 15d-PG J2 was released by human articular chondrocytes and found in joint synovial fluids taken from osteoarthritis or rheumatoid arthritis patients. Proinflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) up-regulated chondrocyte release of 15d-PG J2. PG D2 synthase mRNA expression was up-regulated by IL-1beta, TNF-alpha, or nitric oxide. 15d-PG J2 induced apoptosis of chondrocytes from osteoarthritis or rheumatoid arthritis patients as well as control nonarthritic subjects in a time- and dose-dependent manner and in a peroxisome proliferator-activated receptor gamma-dependent manner. Peroxisome proliferator-activated receptor gamma expression was up-regulated by IL-1beta and TNF-alpha. Inhibition of NF-kappaB, and the activation of p38 MAPK were also found to be involved in 15d-PG J2-induced chondrocyte apoptosis. Such signal pathways led to the activation of the downstream pro-apoptotic molecule p53 and caspase cascades. Together, these results suggest that 15d-PGJ2 may play an important role in the pathogenesis of arthritic joint destruction via a regulation of chondrocyte apoptosis.
Apoptosis↗
HTLV-I env protein acts as a major antigen in patients with HTLV-I-associated arthropathy.
Our objective was to investigate the pathological mechanisms of HTLV-I (human T-cell leukemia virus type I)-associated chronic arthritis (HAAP) with respect to T-cell response to HTLV-I viral proteins. We examined T-cell clonality and the antigen recognized by T cells from the inflamed synovium of patients with HAAP by using histology, a single-strand conformation polymorphism (SSCP) analysis and T cell receptor (TCR) sequencing. The SSCP analysis showed oligoclonal expansion of T cells in the synovium, suggesting an antigen-mediated stimulation. In contrast, there was less clonal expansion in peripheral blood lymphocytes (PBL). The expression of HTLV-1 env and tax mRNA was detected in the affected synovium as well as in PBL. A number of T-cell clones in the synovium recognized HTLV-I env and tax proteins. Twenty-seven (24.9%) of 109 examined T-cell clones in the joints were HTLV-I env reactive, and 7 clones (6.4%) were HTLV-I tax reactive. Junctional sequence analysis of synovial T cells showed a lack of highly conserved amino acid motifs in the complementarity-determining region 3 (CDR3) of HTLV-I env and tax reactive T cells, suggesting that these cells recognized multiple T-cell epitopes on HTLV-I antigen. These findings suggest that HTLV-I env protein acts as a major antigen and may play a role in the development of arthropathy in patients with HAAP.
Amino Acid Sequence↗
Proteomic surveillance of autoimmunity in osteoarthritis: identification of triosephosphate isomerase as an autoantigen in patients with osteoarthritis.
OBJECTIVE: Autoimmunity to proteins, such as type II collagen and cartilage intermediate layer protein, that are produced by chondrocytes has been reported in patients with osteoarthritis (OA) as well as in patients with rheumatoid arthritis (RA). However, it remains to be determined whether the overall specificities of the autoimmunity differ between OA and RA patients. This study sought to clarify the differences by applying proteomic surveillance for the detection of autoantigens comprehensively. METHODS: Serum samples were obtained from 20 patients with OA, 20 patients with RA, and 20 healthy volunteers. Human chondrocyte proteins were separated from the sera by 2-dimensional electrophoresis, and antigenic protein spots were detected by Western blotting. The antigenic proteins were then identified by mass fingerprinting. The antigenicity of the identified proteins was confirmed and the prevalence of the autoantibodies in the OA, RA, and other disease groups was determined with the use of recombinant proteins. In addition, autoepitopes were mapped on the antigens. RESULTS: Nineteen protein spots were recognized only by the OA sera, but not by the RA sera. One of these proteins was identified as triosephosphate isomerase (TPI). IgG-type anti-TPI autoantibodies were detected in 24.7% of the serum samples and 24.1% of the synovial fluid samples from the patients with OA, whereas <6% of the RA and systemic lupus erythematosus samples were positive for anti-TPI. In addition, multiple autoepitopes were identified on TPI. CONCLUSION: The overall profile of autoimmunity in OA differs from that in RA, which may reflect the OA-specific pathologic role of autoimmunity. The autoantibody to TPI, detected predominantly in the OA samples and produced by the antigen-driven mechanism, has the potential to be used as a diagnostic marker for OA.
Adult↗
Identification of a new autoantibody in patients with chronic hepatitis.
To comprehensively study autoantibodies in patients with chronic hepatitis (CH), especially those with hepatitis C virus (HCV) infection, proteins extracted from HepG2 cells were separated by two-dimensional electrophoresis. Spots reacting with sera from 15 patients with CH-C were detected by Western blotting. Proteins extracted from the spots were subjected to mass spectroscopy for identification by mass fingerprinting. Antigenicity of the proteins identified was confirmed by Western blotting and enzyme-linked immunoabsorbent assay. The localization of the autoantigens so detected was investigated by immunohistochemistry. Among 20 protein spots detected, four were identified as actin, heat shock protein (HSP) 70, HSP60, and a novel protein (hepalaminin). Hepalaminin consists of two domains of laminin beta-2 and a specific domain. Autoantibodies against the specific domain were detected in 60.8% of patients with CH-C, 37.7% of those with CH-B, 42.3% of those with autoimmune CH, 28.6% of nonalcoholic steatohepatitis, 10.0% of asymptomatic HCV carriers, but in no healthy volunteers. Antihepalaminin positivity in CH-C and CH-B was related to histologic grading. Immunohistochemical staining demonstrated that hepalaminin is present in the cytoplasm of hepatocytes and cholangiocytes but not of fibroblasts or the vascular epithelium. Hepalaminin is a novel protein expressed in hepatocytes and cholangiocytes. Autoimmunity to this protein may exacerbate inflammation in chronic viral hepatitis.
Amino Acid Sequence↗
Diffuse esophageal spasm.
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Catheterization↗
Neoantigens in osteoarthritic cartilage.
PURPOSE OF REVIEW: Osteoarthritis has been considered a degenerative disease. However, recent evidence supports involvement of immunologic mechanisms in this pathophysiology: for example, inflammation of synovial tissue is observed in osteoarthritis. In osteoarthritis, the proinflammatory cytokine interleukin-1, which is produced by activated synoviocytes and mononuclear cells and has catabolic effects on chondrocytes, is one of the most involved. The immune reaction would require driving antigens. This review describes autoantigens in osteoarthritis and discusses their roles in triggering and/or perpetuating synovitis and joint cartilage destruction in osteoarthritis. RECENT FINDINGS: Several autoantigens/autoantibodies have been reported in osteoarthritis, such as the cartilage intermediate layer protein. Furthermore, recent comprehensive proteomic surveillance has revealed that comparable numbers of autoantigens were detected in osteoarthritis and rheumatoid arthritis, and that some of them were recognized predominantly in osteoarthritis rather than in rheumatoid arthritis. In addition, it was revealed that the cartilage intermediate layer protein immunization of mice developed calcification of tendons, thus indicating that autoimmunity modulates functions of target molecules. SUMMARY: Osteoarthritis-specific autoantigens may drive chronic synovitis and may thereby contribute to production of cytokines to upregulate proteases, which lead to chondrocyte and cartilage damage. In addition, autoimmunity may damage joint components by modulating functions of the target molecules.
Autoantibodies↗
Identification of beta-tubulin isoform V as an autoantigen in allergic rhinitis by a proteomic approach.
Autoantibodies to IgE and beta2-adrenergic receptor have been reported in patients with allergic rhinitis. To investigate whether autoimmunity in allergic rhinitis is directed to such limited molecules or directed to a wide range of self proteins, we here attempted to survey autoantigens/autoantibodies comprehensively, using proteomics. Specifically, we separated proteins extracted from peripheral blood mononuclear cells by 2-dimensional electrophoresis and then detected autoantigens by subsequent western blotting with sera from patients with allergic rhinitis. As a result, we detected multiple autoantigens, some of which were further identified by mass fingerprinting. Next, we confirmed antigenicity of one of the identified autoantigens, beta-tubulin isoform V (beta-tubV), using a recombinant protein and then measured prevalence of the anti-beta-tubV autoantibodies. As a result, 52% of the tested patients with allergic rhinitis were found to possess anti-beta-tubV autoantibodies. Our study indicates that autoimmunity is a common phenomena and beta-tubV is one of the major autoantigens in allergic rhinitis.
Adult↗
Identification of autoantibodies with the corresponding antigen for repetitive coxsackievirus infection-induced cardiomyopathy.
BACKGROUND: The hypothesis that viral myocarditis causes an autoimmune response and subsequent dilated cardiomyopathy is controversial. To further investigate the autoimmune mechanism of cardiac dilatation and dysfunction after repeated episodes of viral myocarditis, the cardiac autoantigens induced by repetitive coxsackievirus B3 (CVB3) infection were examined. METHODS AND RESULTS: Male inbred A/J mice were inoculated intraperitoneally with CVB3 at 3 and 40 weeks of age. At 8 weeks after the second inoculation, the mortality of the repetitive CVB3 group was significantly increased compared with that of the control group, and was associated with a significant reduction in fractional shortening and marked left ventricular dilatation without inflammatory cell infiltration. The cardiac antigens in the repetitive CVB3 infection were identified by 2-dimensional electrophoresis and subsequent liquid chromatography/tandem mass spectrometry (LC-MS/MS) using the serum at 2 weeks after the second inoculation. LC-MS/MS and immunohistochemistry demonstrated alpha-cardiac actin and heat shock protein 60 (HSP60) as cardiac near-surface antigens induced by the repetitive CVB3 infection. Immunoelectron microscopy disclosed the selective localization of anti-IgM antibody on the membrane of the myocytes in the repetitive CVB3 group. CONCLUSIONS: IgM antibodies against alpha-cardiac actin and HSP60, which were induced by repetitive CVB3 infection, may play an important role in the pathophysiology of the subsequent cardiac dysfunction and dilatation.
Animals↗
[A case of Zollinger-Ellison syndrome due to duodenal gastrinoma with incurable diarrhea which was led to diagnosis by endoscopic examination].
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Aged↗