PubMed Health⌕ Search

Biomedical subjects

Kusuki Nishioka

Publications and source records attributed to Kusuki Nishioka.

At least 19 recordsLinked to original sources
PubMed2006

Cytoplasmic destruction of p53 by the endoplasmic reticulum-resident ubiquitin ligase 'Synoviolin'.

Synoviolin, also called HRD1, is an E3 ubiquitin ligase and is implicated in endoplasmic reticulum -associated degradation. In mammals, Synoviolin plays crucial roles in various physiological and pathological processes, including embryogenesis and the pathogenesis of arthropathy. However, little is known about the molecular mechanisms of Synoviolin in these actions. To clarify these issues, we analyzed the profile of protein expression in synoviolin-null cells. Here, we report that Synoviolin targets tumor suppressor gene p53 for ubiquitination. Synoviolin sequestrated and metabolized p53 in the cytoplasm and negatively regulated its cellular level and biological functions, including transcription, cell cycle regulation and apoptosis. Furthermore, these p53 regulatory functions of Synoviolin were irrelevant to other E3 ubiquitin ligases for p53, such as MDM2, Pirh2 and Cop1, which form autoregulatory feedback loops. Our results provide novel insights into p53 signaling mediated by Synoviolin.

Animals↗
PubMed2006

Molecular epidemiology of hepatitis A virus in metropolitan areas in Japan.

BACKGROUND: Transmission routes of hepatitis A virus (HAV) in Japan have changed. The present study investigated changes of transmission routes in relation to genetic drift. METHODS: All 60 patients who were admitted between 1993 and 2003 with a diagnosis of hepatitis A were retrospectively analyzed. Nucleotide sequences of the VP1/2A region of the HAV recovered from their sera were determined. RESULTS: The suspected transmission routes were household contact, 19 (31%); food or waterborne, 16 (27%); homosexual activity, 11 (18%); international travel, 4 (7%); and unknown 10. (17%). The 11 patients presumably infected through homosexual activity were found exclusively in 1998 and 1999. The proportion of patients exposed through homosexual behavior and household contact was higher in those 2 years than in other years. Nucleotide sequences could be determined for 58 patients. Fifty-seven of the 58 sequences belonged to genotype IA HAV, with less than 10% nucleotide diversity. Of the 27 sequences isolated during 1998 and 1999, 25 had an identical nucleotide sequence regardless of the suspected transmission route. In contrast, sequences obtained in the other years differed from one another. A phylogenetic tree constructed from sequences recovered from patients without a history of travel abroad showed several clusters. CONCLUSIONS: Our results suggest that (1) HAV acquired through homosexual activity may be transmitted to nonhomosexual individuals; (2) hepatitis A in metropolitan areas in Japan is caused mainly by sporadic infection with genotype IA HAV; and (3) several subtypes of genotype IA HAV are endemic in Japan.

Adult↗
PubMed2006

Fibulin-4 is a target of autoimmunity predominantly in patients with osteoarthritis.

Autoimmunity to chondrocyte-producing proteins has been reported in patients with osteoarthritis (OA) as well as in those with rheumatoid arthritis (RA). To answer whether or not OA-specific autoimmunity exist, we performed screening of chondrocyte-producing autoantigens by two-dimensional electrophoresis and Western blotting with each of 20 OA and 20 RA serum samples. We identified an apparently OA-specific autoantigen spot with a molecular mass of 52 kDa and a Isoelectric point of 4.1 as fibulin-4 by mass fingerprinting. By preparing recombinant proteins of fibulin-4, we determined prevalence of the autoantibodies to fibulin-4 in 92 patients with OA, 67 patients with RA, 40 patients with systemic lupus erythematosus, and 43 patients with systemic scleroderma. As a result, the IgG type anti-fibulin-4 autoantibodies were detected in 23.9% of sera from patients with OA, in 8.9% of sera from patients with RA, in 2.5% of sera from patients with systemic lupus erythematosus, and in 9.3% of sera from patients with systemic scleroderma. Furthermore, we immunized DBA/1J, ICR, BALB/c, and C57BL/6 mice with the recombinant fibulin-4 proteins to investigate arthritogenecity of fibulin-4. As a result, mild synovitis was detected in all of the four strains. In addition, we demonstrated expression of fibulin-4 in chondrocytes at both mRNA and protein levels in vivo and in vitro by RT-PCR, Western blotting, and immunohistochemistry. Taken together, fibulin-4, expressed in chondrocytes and recognized as an autoantigen mainly in OA rather than in RA, may play pathogenic roles in OA.

Adult↗
PubMed2006

Electroconvulsive therapy improves severe pain associated with fibromyalgia.

The pathophysiology of fibromyalgia remains unknown. Several reports have recently suggested the novel concept that fibromyalgia is due to the central nervous system becoming hyper-responsive to a peripheral stimulus. The effect of electroconvulsive therapy (ECT) as pain remedication in cases of fibromyalgia without major depressive disorder was studied in a prospective trial lasting three months. All of the patients taking part in the study fulfilled the American College of Rheumatology diagnostic criteria for fibromyalgia. Technetium-99m ethyl cysteinate dimer single photon emission computed tomography was used to assess regional cerebral blood flow (rCBF) before and after a course of ECT. Pain assessment in the patients was undertaken by use of the visual analog scale (VAS) and by evaluation of tender points (TPs). Beck's depression inventory (BDI) was further used to assess depressive mood change in the patients. Our study clearly demonstrated that pain was significantly less severe after ECT, as indicated by the VAS scale for pain and the evaluation of TPs. A further notable observation was that thalamic blood flow was also improved. We conclude that a course of ECT produced notable improvements in both intractable severe pain associated with fibromyalgia and also in terms of thalamic blood flow.

Adult↗
PubMed2006

Enhanced production of MMP-1, MMP-3, MMP-13, and RANTES by interaction of chondrocytes with autologous T cells.

It has been reported that T cells and chondrocytes interact through cell surface molecules such as MHC, CD4 or CD8 in osteoarthritis (OA) and T cells are activated. The objective of this study is to investigate the responses of chondrocyte-T cell interaction in terms of metalloprotease (MMP) and chemokine production. Articular cartilage and autologous blood were obtained from patients with OA and fracture who under went prosthetic surgery. Synovial fluid (SF) was collected from OA patients. Isolated chondrocytes were co-cultured with autologous T cells. SF cells were analyzed by immunostaining or Alcian blue staining. The production of MMP-1, MMP-3, MMP-13, and regulated on activation, normal T expressed and secreted (RANTES) was enhanced by direct co-culture compared to indirect co-culture using Transwell. Production ratio of RANTES in OA was significantly higher than non-arthritic samples. CD3 positive mononuclear cells and chondrocyte-like cells were found in SF. Chondrocyte-T cell contact was more adhesive in OA samples. These results showed the production of MMPs and RANTES was enhanced by the interaction and that chondrocyte-T cell contact was possible in vivo.

Aged↗
PubMed2006

Comparative analysis of gene expression profiles in intact and damaged regions of human osteoarthritic cartilage.

OBJECTIVE: To analyze the differences in gene expression profiles of chondrocytes in intact and damaged regions of cartilage from the same knee joint of patients with osteoarthritis (OA) of the knee. METHODS: We compared messenger RNA expression profiles in regions of intact and damaged cartilage (classified according to the Mankin scale) obtained from patients with knee OA. Five pairs of intact and damaged regions of OA cartilage were evaluated by oligonucleotide array analysis using a double in vitro transcription amplification technique. The microarray data were confirmed by real-time quantitative polymerase chain reaction (PCR) amplification and were compared with previously published data. RESULTS: About 1,500 transcripts, which corresponded to 8% of the expressed transcripts, showed > or = 2-fold differences in expression between the cartilage tissue pairs. Approximately 10% of these transcripts (n = 151) were commonly expressed in the 5 patient samples. Accordingly, 114 genes (35 genes expressed in intact > damaged; 79 genes expressed in intact < damaged) were selected. The expression of some genes related to the wound-healing process, including cell proliferation and interstitial collagen synthesis, was higher in damaged regions than in intact regions, similar to the findings for genes that inhibit matrix degradation. Comparisons of the real-time quantitative PCR data with the previously reported data support the validity of our microarray data. CONCLUSION: Differences between intact and damaged regions of OA cartilage exhibited a similar pattern among the 5 patients examined, indicating the presence of common mechanisms that contribute to cartilage destruction. Elucidation of this mechanism is important for the development of effective treatments for OA.

Cartilage, Articular↗
PubMed2006

Catabolic stress induces features of chondrocyte senescence through overexpression of caveolin 1: possible involvement of caveolin 1-induced down-regulation of articular chondrocytes in the pathogenesis of osteoarthritis.

OBJECTIVE: Articular chondrocyte senescence is responsible, at least in part, for the increased incidence of osteoarthritis (OA) with increased age. Recently, it was suggested that caveolin 1, a 21-24-kd membrane protein, participates in premature cellular senescence. Caveolin 1 is the principal structural component of caveolae, vesicular invaginations of the plasma membrane. This study was undertaken to investigate whether the catabolic factors oxidative stress and interleukin-1beta (IL-1beta) induce features of premature senescence of articular chondrocytes through up-regulation of caveolin 1 expression. METHODS: Caveolin 1 expression was investigated in human OA cartilage by real-time polymerase chain reaction and in rat OA cartilage by immunohistologic analysis. We studied whether IL-1beta and H2O2 induce caveolin 1 expression in OA chondrocytes and analyzed the relationship between cellular senescent phenotypes and caveolin 1 expression in human chondrocytes. RESULTS: In human and rat OA articular cartilage, caveolin 1 positivity was associated with cartilage degeneration. Both IL-1beta and H2O2 up-regulated caveolin 1 messenger RNA and protein levels, and both treatments induced marked expression of senescent phenotypes: altered cellular morphology, cell growth arrest, telomere erosion, and specific senescence-associated beta-galactosidase activity. Caveolin 1 overexpression induced p38 MAPK activation and impaired the ability of chondrocytes to produce type II collagen and aggrecan. In contrast, down-regulation of caveolin 1 with antisense oligonucleotide significantly inhibited the features of chondrocyte senescence induced by catabolic factors. Caveolin 1 induction and stresses with both IL-1beta and H2O2 up-regulated p53 and p21 and down-regulated phosphorylated retinoblastoma (Rb), suggesting that the p53/p21/Rb phosphorylation pathway, as well as prolonged p38 MAPK activation, may mediate the features of chondrocyte senescence induced by stress. CONCLUSION: Our findings suggest that IL-1beta and oxidative stress induce features of premature senescence in OA chondrocytes, mediated, at least in part, by stress-induced caveolin 1 expression. This indicates that caveolin 1 plays a role in the pathogenesis of OA via promotion of chondrocyte down-regulation.

Aggrecans↗
PubMed2006

Distinct signaling pathways are involved in hypoxia- and IL-1-induced VEGF expression in human articular chondrocytes.

Recent data suggest that vascular endothelial growth factor (VEGF) is involved in the pathogenesis of osteoarthritis (OA). Cartilage is an avascular tissue, leading to a low cartilage O2 level. Thus, in a variety of pathologic or physiologic conditions, VEGF is partly regulated by hypoxic stress. The implications of hypoxia for VEGF expression by OA chondrocytes, however, are not known. We investigated the regulatory system of VEGF in OA chondrocytes under hypoxic conditions. Chondrocytes were obtained from articular cartilage of patients with OA. Cells were cultured and then incubated under hypoxic (95% N2, 5% CO2) or normoxic conditions, with or without interleukin (IL)-1 (10 ng/mL) stimulation. The mitogen activated protein kinase (MAPK) inhibitors were also used. VEGF levels in the culture supernatants were measured using an enzyme-linked immunosorbent assay. Western blot analysis was used to examine the expression of hypoxia inducible factor (HIF)-1alpha. Hypoxia significantly increased VEGF levels (p<0.05). Hypoxia-induced VEGF secretion was abolished by p38MAPK inhibitor, but not by JNK inhibitor. In contrast, IL-1-induced VEGF secretion was blocked by JNK inhibitor, and not by p38MAPK inhibitor. Both hypoxia and IL-1-induced HIF-1alpha were attenuated by p38 MAPK and JNK inhibitors. We demonstrate that hypoxia and IL-1 induce VEGF production in chondrocytes through distinct MAPK signaling pathways, indicating that VEGF is induced in a HIF-1-dependent or -independent manner in chondrocytes.

Aged↗
PubMed2006

Proteomic surveillance of autoantigens in relapsing polychondritis.

Relapsing polychondritis (RP) is a systemic inflammatory disease, in which autoimmunity to cartilage-related components is thought to be involved in its pathogenesis. However, the autoimmune profile in RP has not been studied fully. We therefore investigated autoantibodies/autoantigens in RP comprehensively, by 2-dimensional electrophoresis (2DE), subsequent western blotting (WB) and mass spectrometry, using cell-extracted proteins as the antigen source. As a result, we detected 15 autoantigens on 2DE-WB, and further identified five of them. On average, one RP serum recognized approximately 8 out of the 15 autoantigens. Frequencies of the autoantibodies to the 5 identified antigens of tubulin alpha ubiquitous/6, vimentin, alpha enolase, calreticulin, and colligin-1/-2 were 91%, 46%, 36%, 82%, and 36%, respectively. ELISA using recombinant proteins for them revealed that frequencies of the autoantibodies to tubulin alpha ubiquitous, vimentin, alpha enolase, calreticulin, and colligin-1 were 36%, 64%, 46%, 27%, and 18%, respectively. Our data demonstrated that the autoimmune reaction was not restricted to cartilagerelated components, rather a variety of autoimmune responses occurred in patients with RP, which may be involved in the pathophysiology of RP. In addition, the proteomic approach using cell-extracted proteins would be a powerful way to investigate autoantigens.

Autoantibodies↗
PubMed2006

Identification of novel citrullinated autoantigens of synovium in rheumatoid arthritis using a proteomic approach.

Recently, autoantibodies to some citrullinated autoantigens have been reported to be specific for rheumatoid arthritis (RA). However, an entire profile of and autoimmunity of the citrullinated proteins have been poorly understood. To understand the profile, we examined citrullinated autoantigens by a proteomic approach and further investigated the significance of citrullination in antigenicity of one of the autoantigens. Specifically, we detected citrullinated autoantigens in synovial tissue of a patient with RA by two-dimensional electrophoresis and Western blotting by using pooled sera from five patients with RA and anti-citrulline antibodies. After identifying the detected autoantigens by mass spectrometry, we investigated the contribution of citrullination to autoantigenicity by using a recombinant protein with or without citrullination on one of the identified novel citrullinated autoantigens. As a result, we found 51 citrullinated protein spots. Thirty (58.8%) of these spots were autoantigenic. We identified 13 out of the 30 detected citrullinated autoantigenic proteins. They contained three fibrinogen derivatives and several novel citrullinated autoantigens (for example, asporin and F-actin capping protein alpha-1 subunit [CapZalpha-1]). We further analyzed the contribution of citrullination to autoantigenicity in one of the detected citrullinated autoantigens, CapZalpha-1. As a result, frequencies of autoantibodies to non-citrullinated CapZalpha-1 were 36.7% in the RA group tested, 10.7% in the osteoarthritis (OA) group, and 6.5% in healthy donors. On the other hand, those to citrullinated CapZalpha-1 were 53.3% in the RA group, 7.1% in the OA group, and 6.5% in the healthy donors. This shows that autoantigenicity of citrullinated or non-citrullinated CapZalpha-1 is relevant to RA. The antibody titers to the citrullinated CapZalpha-1 were significantly higher than those to the non-citrullinated CapZalpha-1 in 36.7% of patients; however, the other patients showed almost equal antibody titers to both citrullinated and non-citrullinated CapZalpha-1. Therefore, the autoantibodies would target citrulline-related and/or citrulline-unrelated epitope(s) of CapZalpha-1. In conclusion, we report a profile of citrullinated autoantigens for the first time. Even though citrullination is closely related to autoantigenicity, citrullination would not always produce autoantigenicity in RA. Citrullinated and non-citrullinated autoantigens/autoepitopes would have different pathological roles in RA.

Adult↗
PubMed2006

Resistance to endoplasmic reticulum stress is an acquired cellular characteristic of rheumatoid synovial cells.

Synoviolin is an endoplasmic reticulum (ER)-resident E3 ubiquitin ligase which plays a critical role in ER-associated degradation (ERAD). We found that Synoviolin is a novel causative factor for rheumatoid arthritis (RA), which is especially up-regulated in proliferating synovial cells in the disease. We attempted to examine the role of Synoviolin in ER stress-induced apoptosis and proliferation of synovial cells. RA synovial cells (RSCs) were refractory to ER stress-induced apoptosis compared with HEK293 or HeLa cells. RSCs were also more resistant to the apoptosis than synovial cells from osteoarthritis patients, significantly. Down-regulation of Synoviolin by siRNA increased the susceptibility to ER stress-induced apoptosis in RSCs. Knock-down of Synoviolin by siRNA did not only induce apoptosis of RSCs but also inhibited their proliferation in vitro. These data suggest that RSCs are extraordinarily refractory to ER stress-induced apoptosis, and we termed this special property 'hyper-ERAD'. Since Synoviolin is overexpressed in RSCs, and is known to play a critical role in the ERAD system as E3 ubiquitin ligase, hyper-ERAD is likely to present in these cells. Subsequently, the hyper-ERAD may cause synovial hyperplasia through its anti-apoptotic effect in RA. Further analyses are necessary to address this point, however, resistance to ER stress-induced apoptosis, or hyper-ERAD is a noteworthy new cellular characteristic of RSCs.

Apoptosis↗
PubMed2005

Rheumatoid arthritis as a hyper-endoplasmic-reticulum-associated degradation disease.

We introduce Synoviolin as a novel pathogenic factor in rheumatoid arthritis (RA). Experimental studies indicate that this endoplasmic reticulum (ER)-resident E3 ubiquitin ligase has important functions in the ER-associated degradation (ERAD) system, an essential system for ER homeostasis. Overexpression of Synoviolin in mice causes arthropathy with synovial hyperplasia, whereas heterozygous knockdown results in increased apoptosis of synovial cells and resistance to collagen-induced arthritis in mice. On the basis of these experimental data, we propose that excess elimination of unfolded proteins (that is, 'hyper-ERAD') by overexpression of Synoviolin triggers synovial cell overgrowth and hence a worsening of RA. Further analysis of the hyper-ERAD system may permit the complex pathomechanisms of RA to be uncovered.

Amino Acid Sequence↗
PubMed2005

Catabolic stress induces expression of hypoxia-inducible factor (HIF)-1 alpha in articular chondrocytes: involvement of HIF-1 alpha in the pathogenesis of osteoarthritis.

Transcription factor hypoxia-inducible factor (HIF)-1 protein accumulates and activates the transcription of genes that are of fundamental importance for oxygen homeostasis - including genes involved in energy metabolism, angiogenesis, vasomotor control, apoptosis, proliferation, and matrix production - under hypoxic conditions. We speculated that HIF-1alpha may have an important role in chondrocyte viability as a cell survival factor during the progression of osteoarthritis (OA). The expression of HIF-1alpha mRNA in human OA cartilage samples was analyzed by real-time PCR. We analyzed whether or not the catabolic factors IL-1beta and H2O2 induce the expression of HIF-1alpha in OA chondrocytes under normoxic and hypoxic conditions (O2 <6%). We investigated the levels of energy generation, cartilage matrix production, and apoptosis induction in HIF-1alpha-deficient chondrocytes under normoxic and hypoxic conditions. In articular cartilages from human OA patients, the expression of HIF-1alpha mRNA was higher in the degenerated regions than in the intact regions. Both IL-1beta and H2O2 accelerated mRNA and protein levels of HIF-1alpha in cultured chondrocytes. Inhibitors for phosphatidylinositol 3-kinase and p38 kinase caused a significant decrease in catabolic-factor-induced HIF-1alpha expression. HIF-1alpha-deficient chondrocytes did not maintain energy generation and cartilage matrix production under both normoxic and hypoxic conditions. Also, HIF-1alpha-deficient chondrocytes showed an acceleration of catabolic stress-induced apoptosis in vitro. Our findings in human OA cartilage show that HIF-1alpha expression in OA cartilage is associated with the progression of articular cartilage degeneration. Catabolic-stresses, IL-1beta, and oxidative stress induce the expression of HIF-1alpha in chondrocytes. Our results suggest an important role of stress-induced HIF-1alpha in the maintenance of chondrocyte viability in OA articular cartilage.

Aged↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2005

Identification of a crucial site for synoviolin expression.

Synoviolin is an E3 ubiquitin ligase localized in the endoplasmic reticulum (ER) and serving as ER-associated degradation system. Analysis of transgenic mice suggested that synoviolin gene dosage is implicated in the pathogenesis of arthropathy. Complete deficiency of synoviolin is fatal embryonically. Thus, alternation of Synoviolin could cause breakdown of ER homeostasis and consequently lead to disturbance of cellular homeostasis. Hence, the expression level of Synoviolin appears to be important for its biological role in cellular homeostasis under physiological and pathological conditions. To examine the control of protein level, we performed promoter analysis to determine transcriptional regulation. Here we characterize the role of synoviolin transcription in cellular homeostasis. The Ets binding site (EBS), termed EBS-1, from position -76 to -69 of the proximal promoter, is responsible for synoviolin expression in vivo and in vitro. Interestingly, transfer of EBS-1 decoy into NIH 3T3 cells conferred not only the repression of synoviolin gene expression but also a decrease in cell number. Fluorescence-activated cell sorter analysis using annexin V staining confirmed the induction of apoptosis by EBS-1 decoy and demonstrated recovery of apoptosis by overexpression of Synoviolin. Our results suggest that transcriptional regulation of synoviolin via EBS-1 plays an important role in cellular homeostasis. Our study provides novel insight into the transcriptional regulation for cellular homeostasis.

Animals↗