Biomedical subjects

Tadashi Matsuda

Publications and source records attributed to Tadashi Matsuda.

At least 55 records · Page 3Linked to original sources

PubMed2004

Bacterial endotoxin induces IL-20 expression in the glial cells.

The regulatory mechanisms leading to IL-20 expression during infection have not been elucidated. In the present study, we found that bacterial lipopolysaccharide (LPS) induced IL-20 expression in the primary cultured glial cells and RAW264.7 macrophage cell line. Pretreatment with protein synthesis inhibitor puromycin or cycloheximide failed to inhibit the expression of IL-20, suggesting that the expression was not dependent on de novo protein synthesis. Myeloid differentiation factor 88 (MyD88) is an important adaptor molecule for Toll-like receptor signaling. We observed complete inhibition of LPS-induced expression of IL-20 in the primary cultured glial cells prepared from MyD88-deficient mice. Furthermore, a p38 MAP kinase inhibitor, SB203580, inhibited LPS-induced expression of IL-20 mRNA. LPS-induced p38 MAP kinase phosphorylation was delayed in MyD88-deficient glial cells. Therefore, it is suggested that LPS induces IL-20 expression through MyD88-p38-dependent mechanisms. As dexamethasone inhibited LPS-induced IL-20 expression, the expression of IL-20 is regulated by a negative feedback loop mediated through glucocorticoids. Therefore, it is suggested that IL-20 may play a crucial role in inflammatory conditions in the brain.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Bacterial endotoxin induces STAT3 activation in the mouse brain.

In the present study, we investigated regulatory mechanisms of bacterial endotoxin-induced STAT3 activation in the brain. Intraperitoneal injection of lipopolysaccharide (LPS) dose-dependently (0.5-5000 microg/kg) induced STAT3 phosphorylation in the hypothalamus. LPS-induced STAT3 phosphorylation was peaked at 2-4 h and declined there after. Moreover, intracerebroventricular injection of LPS induced STAT3 phosphorylation in the cortex and the hippocampus, indicating that central as well as peripheral LPS can act in the brain to induce STAT3 activation. Glucocorticoids are known to play a physiological role in the feedback inhibition of immune/inflammatory responses in the endocrine system. Interestingly, we observed no effect of dexamethasone on LPS-induced STAT3 phosphorylation in the hypothalamus. These findings point to the important role of STAT3 in the neuroimmune interaction of inflammation in the brain.

Animals↗

PubMed2004

Tyrosine kinase 2 interacts with and phosphorylates receptor for activated C kinase-1, a WD motif-containing protein.

Receptor for activated C kinase (Rack)-1 is a protein kinase C-interacting protein, and contains a WD repeat but has no enzymatic activity. In addition to protein kinase C, Rack-1 also binds to Src, phospholipase Cgamma, and ras-GTPase-activating proteins. Thus, Rack-1 is thought to function as a scaffold protein that recruits specific signaling elements. In a cytokine signaling cascade, Rack-1 has been reported to interact with the IFN-alphabeta receptor and Stat1. In addition, we show here that Rack-1 associates with a member of Jak, tyrosine kinase 2 (Tyk2). Rack-1 interacts weakly with the kinase domain and interacts strongly with the pseudokinase domain of Tyk2. Rack-1 associates with Tyk2 via two regions, one in the N terminus and one in the middle portion (aa 138-203) of Rack-1. Jak activation causes the phosphorylation of tyrosine 194 on Rack-1. After phosphorylation, Rack-1 is translocated toward the perinuclear region. In addition to functioning as a scaffolding protein, these results raise the possibility that Rack-1 functions as a signaling molecule in cytokine signaling cascades.

Amino Acid Motifs↗

PubMed2004

The role of Tyk2, Stat1 and Stat4 in LPS-induced endotoxin signals.

Mice lacking Tyk2, Stat1 or Stat4, which are members of the Jak-Stat signaling cascade, were resistant to LPS-induced endotoxin shock. Interestingly, Tyk2-deficient mice had higher resistance to LPS challenge than mice lacking either Stat1 or Stat4. The activation of MAPK and NF-kappaB by LPS, and the production of TNF-alpha and IL-12 after LPS injection, were not abrogated by the absence of Tyk2, Stat1 or Stat4. In Stat1-deficient mice, the induction of IFN-beta by LPS in macrophages was severely reduced, although the serum level of IFN-gamma was elevated after LPS injection. In contrast, in Stat-4 deficient mice, the induction of IFN-beta by LPS was normal, but the serum level of IFN-gamma remained low after LPS injection. Interestingly, the induction of both IFN-beta and IFN-gamma by LPS was severely reduced in Tyk2-deficient mice. Therefore, Stat1 and Stat4 independently play substantial roles in the susceptibility to LPS. Tyk2 is essential for LPS-induced endotoxin shock, and this signaling pathway is transduced by the activation of Stat1 and Stat4.

Animals↗

PubMed2004

The RING domain of PIASy is involved in the suppression of bone morphogenetic protein-signaling pathway.

Bone morphogenetic proteins (BMPs) play central roles in differentiation, development, and physiologic tissue remodeling. Recently, we have demonstrated that a protein inhibitor of activated STAT, PIASy, suppresses TGF-beta signaling by interacting with Sma and MAD-related protein 3 (Smad3). In this study, we examined a PIASy-dependent inhibitory effect on BMP signaling. PIASy expression was induced by BMP-2 stimulation and suppressed BMP-2-dependent Smad activity in hepatoma cells. Furthermore, BMP-2-regulated Smads directly bound to PIASy. We also demonstrated that the RING domain of PIASy played an important role in PIASy-mediated suppression of Smad activity. We here provide evidence that the inhibitory action of PIASy on BMP-regulated Smad activity was due to direct physical interactions between Smads and PIASy through its RING domain.

Blotting, Northern↗

PubMed2004

Physical and functional interactions between Daxx and TSG101.

Daxx has been reported to mediate the Fas/JNK-dependent signals in the cytoplasm. However, several evidences have suggested that Daxx is located mainly in the nucleus and functions as a transcriptional regulator. Recently, we identified DMAP1, a TSG101-interacting protein as a Daxx binding partner by yeast two-hybrid screening. TSG101 has been shown to act as transcriptional co-repressor of nuclear hormone receptors. Here we examined whether TSG101also interacts with Daxx directly. The association of Daxx and TSG101 was confirmed using co-expressed tagged proteins. The interaction regions in both proteins were also mapped, and the cellular localization of the interaction was examined. TSG101 formed a complex with Daxx through its coiled-coil domain and co-localized in the nucleus. Furthermore, TSG101 enhanced Daxx-mediated repression of glucocorticoid receptor transcriptional activity. These results provide the novel molecular interactions between Daxx and TSG101, which establish an efficient repressive transcription complex in the nucleus.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Cross-talk between endocrine-disrupting chemicals and cytokine signaling through estrogen receptors.

STAT3 mainly acts as a signal transducer of IL-6 family cytokines and transcriptionally activates specific target genes. STAT3 has also been demonstrated to mediate cellular transformation and is found in numerous cancers. Endocrine-disrupting chemicals (EDCs) are a diverse group of chemicals that bind to estrogen receptors (ERs), mimic estrogenic actions, and may have adverse effects on human health. In our previous study, we demonstrated that estrogens suppressed the STAT3-mediated transcription activity through ERs. In this study, we examined the effects of EDCs on STAT3-mediated signaling through ERs. Surprisingly, some of EDCs enhanced STAT3-mediated transcription activity through ERs. This finding strongly suggests that EDCs may play an important role in the endocrine functions by mimicking cytokine activity by stimulating STAT3 actions through ERs.

Cell Line, Tumor↗

PubMed2004

Physical and functional interactions between Daxx and DNA methyltransferase 1-associated protein, DMAP1.

Daxx has been shown to play an essential role in type I IFN-alphabeta-mediated suppression of B cell development and apoptosis. Recently, we demonstrated that Tyk2 is directly involved in IFN signaling for the induction and translocation of Daxx, which may result in growth arrest and/or apoptosis of B lymphocyte progenitors. To clarify how Daxx regulates B cell development, we examined Daxx interacting partners by yeast two-hybrid screening. DNA methyltransferase 1 (DNMT1)-associated protein (DMAP1) was identified and demonstrated to interact with Daxx. The interaction regions in both proteins were mapped, and the cellular localization of the interaction was examined. Both Daxx and DMAP1 formed a complex with DNMT1 and colocalized in the nucleus. DMAP1 enhanced Daxx-mediated repression of glucocorticoid receptor transcriptional activity. Furthermore, Daxx protected protein degradation of DMAP1 in vivo. These results provide the novel molecular link between Daxx and DNMT1, which establishes a repressive transcription complex in the nucleus.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Involvement of NF-kappaB in TGF-beta-mediated suppression of IL-4 signaling.

Control of immune response requires the coordinated integration of both stimulatory and inhibitory factors. Therefore, the cross-talk of different signaling pathways is critical in providing an integrated cellular response to multiple external signals. Both interleukin-4 (IL-4) and transforming growth factor (TGF-beta) are pleiotropic cytokines and play critical roles in controlling immune responses. For example, IL-4 mediates important pro-inflammatory functions in asthma including induction of the IgE isotype switch and expression of vascular cell adhesion molecules. Whereas, TGF-beta is secreted from B, T, and dendritic cells as well as macrophages, and negatively regulates their proliferation, differentiation, and activation by other cytokines. In this study, we examined the effect of TGF-beta on IL-4 signaling using B cells as well as embryonic kidney cells. TGF-beta inhibited IL-4-induced IgG1 production and gene expression of germline epsilon transcripts in B cells. In embryonic kidney cells, TGF-beta signals suppressed IL-4-induced transcription, when we monitored using germline epsilon promoter DNA. Furthermore, activation of NF-kappaB resulted in a resistance to TGF-beta-mediated suppression of IL-4 signaling. These results indicate that TGF-beta-mediated regulation of IL-4 signaling may act by targeting NF-kappaB signaling.

Animals↗

PubMed2004

Hapten-induced contact hypersensitivity is enhanced in Tyk2-deficient mice.

BACKGROUND: Previous studies have shown that Tyk2, a member of the Janus family of protein tyrosine kinases, which are activated by a variety of cytokines, plays a crucial role in interleukin (IL)-12-mediated T-cell functions such as IFN-gamma production. On the other hand, hapten-induced contact hypersensitivity (CHS) is mediated by IFN-gamma producing CD8+ T cells and regulated by CD4+ T cells. OBJECTIVE: This study hypothesized that the CHS response might be reduced in Tyk2-deficient mice because of a lack of IFN-gamma production from CD4+ and CD8+ T cells. METHODS: The CHS reaction was evoked in wild-type and Tyk2-deficient mice and the ears of the mice were examined to measure for several cytokines. RESULTS: Ear swelling during CHS was significantly enhanced in Tyk2-deficient mice compared with the controls. IL-12 and IFN-gamma levels at the reaction sites in Tyk2-deficient mice were significantly lower than in the controls, whereas IL-2 and IL-4 levels were elevated. Furthermore, STAT3- and STAT4-phosphorylation in the draining lymph node cells of Tyk2-deficient mice decreased. CONCLUSION: These results suggest that the lack of Tyk2-mediated signal transduction enhances a compensative pathway during CHS.

Animals↗

PubMed2004

Retroperitoneoscopic partial nephrectomy with transient occlusion of renal artery for treatment of small renal tumors.

OBJECTIVES: To evaluate the results of retroperitoneoscopic partial nephrectomy with transient occlusion of the renal artery for treatment of patients with small renal tumors. METHODS: From May 2002 to March 2003, 12 consecutive patients with T1N0M0 renal tumors with a median diameter of 3.0 cm underwent retroperitoneoscopic partial nephrectomy. The renal artery was clamped transiently without occlusion of the renal vein and the tumor was excised with scissors. Intracorporeal renal cooling was achieved by cold saline perfusion of the renal pelvis through a single-J ureteral catheter. Hemostasis was achieved by approximating the renal parenchyma over the perirenal fatty tissue using a retroperitoneoscopic suturing technique. RESULTS: Of the 12 patients, 11 successfully underwent partial nephrectomy retroperitoneoscopically. The median operative time, renal ischemic time, and amount of blood loss in the successful procedures was 220 minutes (range 132 to 340), 50 minutes (range 16 to 115), and 150 mL (range 50 to 800), respectively. The renal calix was opened and repaired in 10 patients. The surgical margin was negative in all patients. The postoperative course was uneventful in all patients, and the return to work was achieved in a median of 18 days (range 9 to 39). The renal function of the affected kidney was well preserved postoperatively, when examined by renal scintigraphy. Neither local recurrence nor distant metastasis was found during the median follow-up period of 10 months (range 1 to 18). CONCLUSIONS: Retroperitoneoscopic partial nephrectomy with transient occlusion of the renal artery is a useful and less-invasive method for resection of small renal tumors. Additional technologic developments to reduce ischemic times and to cool the kidneys laparoscopically are required.

Aged↗

PubMed2004

Superior anti-tumor efficacy of bicalutamide 80 mg in combination with a luteinizing hormone-releasing hormone (LHRH) agonist versus LHRH agonist monotherapy as first-line treatment for advanced prostate cancer: interim results of a randomized study in Japanese patients.

OBJECTIVES: To evaluate bicalutamide (Casodex) 80 mg as a component of maximum androgen blockade (MAB) in Japanese patients with previously untreated advanced prostate cancer. METHODS: 205 patients with previously untreated stage C/D prostate cancer were randomized (1:1) to receive once-daily bicalutamide 80 mg or placebo, each combined with a luteinizing hormone-releasing hormone (LHRH) agonist. Primary study variables were the 12 week prostate-specific antigen (PSA) normalization (i.e. PSA level <or=4 ng/ml) rate, the 12 week overall tumor response rate (proportion with a partial response or better) and the proportion of withdrawals due to adverse drug reactions (ADRs) at follow-up. This interim analysis was undertaken after a minimum of 6 months' follow-up (median 15 months). RESULTS: The 12 week PSA normalization rate was 79.4% for MAB and 38.6% for LHRH agonist monotherapy (P < 0.001). The 12 week overall tumor response rate was 77.5 and 65.3%, respectively (P = 0.063). The withdrawal rate due to ADRs was 8.8% and 10.9%, respectively. There were differences in favor of MAB over monotherapy with respect to time to treatment failure (TTTF) (P = 0.038) and time to progression (TTP) (P = 0.016). There have been too few deaths (n = 10) to analyze survival. The profiles of adverse events and ADRs were broadly similar in the two treatment groups. CONCLUSION: In Japanese patients with advanced prostate cancer, first-line treatment with bicalutamide 80 mg in combination with an LHRH agonist is superior to LHRH agonist monotherapy in terms of the antitumor response at 12 weeks, and also time to treatment failure and progression, and does not compromise treatment safety. The study is ongoing.

Aged↗

PubMed2004

Differential expression of integrin subunits in DU-145/AR prostate cancer cells.

We have established a clonal DU-145 prostate cancer cell line (DU-145/AR) stably transfected with androgen receptor cDNA. We investigated the expression of integrin subunits, adhesion to extracellular matrices, the invasion of DU-145/AR prostate cancer cells. The expression of various integrin subunits and adhesion to various extracellular matrices in DU-145, DU-145/Neo and DU-145/AR cells were examined. The haptoinvasion and the haptotactic migration of these cells were investigated using a Transwell cell culture chamber assay. DU-145/AR cells exhibited lower expression of alpha6 and beta4 integrin subunits and higher expression of alpha2 and alpha5 than DU-145 cells. DU-145/AR cells showed significantly lower adhesion to fibronectin, laminin-1 and laminin-5 than DU-145/ Neo cells, whereas DU-145/AR cells showed higher adhesion to type I and type IV collagen. Haptoinvasion of DU-145/AR cells into Matrigel/fibronectin-coated filter was significantly reduced as compared with DU-145/Neo or DU-145 cells, but there was no significant difference between DU-145/AR and control cells in the haptotactic migration to fibronectin. Dihydrotestosterone (DHT) inhibited the invasive ability of DU-145/AR cells. These results indicate that androgen receptor may play a role in the regulation of adhesion to the extracellular matrices and invasion of prostate cancer cells through influencing the expression of specific integrin subunits.

Androgens↗

PubMed2004

[Diagnosis and treatment of obstructive azoospermia].

There are two types of azoospermia, namely, obstructive and nonobstructive azoospermia. Urologists play a more important role in the former, because many patients of the former can expect spontaneous pregnancy after surgical reconstruction of the seminal tract. In this review, we discuss about the causes, diagnosis, and treatment of obstructive azoospermia. The treatment includes vasovasostomy, epididymovasostomy, and transurethral resection of the ejaculatory duct. Surgical outcomes in our series are also described. The urologist must take care that the obstructive-azoospermic patients do not undergo unnecessary assisted reproduction procedures.

Adult↗

PubMed2003

Regulation of FcepsilonRI-mediated signaling by an adaptor protein STAP-2/BSK in rat basophilic leukemia RBL-2H3 cells.

Crosslinking of multivalent antigen bound IgE transduces FcepsilonRI mediated signaling cascades, which activate nonreceptor-type protein-tyrosine kinases and subsequent tyrosine phosphorylation of cellular proteins, and these are critical elements for degranulation in mast cells. We cloned a novel adaptor molecule, signal transducing adaptor protein (STAP)-2 containing PH and SH2-like domains as a c-fms interacting protein. STAP-2 was identical to a recently cloned adaptor molecule, BKS, a substrate of BRK (breast tumor kinase) tyrosine kinase, although its function is still unknown. To examine a novel function of STAP-2/BSK, we expressed STAP-2/BSK or its mutants in rat basophilic leukemia RBL-2H3 cells. Overexpression of STAP-2/BSK resulted in a suppression of FcepsilonRI-mediated calcium mobilization and degranulation. FcepsilonRI-induced tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma) but not Syk was significantly suppressed in these cells. Furthermore, STAP-2/BSK associated with PLC-gamma in vivo. These data indicate that STAP-2/BSK negatively controls the FcepsilonRI-mediated calcium mobilization and degranulation by direct modulation of tyrosine phosphorylation of PLC-gamma.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Molecular interactions between STAT3 and protein inhibitor of activated STAT3, and androgen receptor.

STAT3 mainly acts as a signal transducer of IL-6 family cytokines and transcriptionally activates specific target genes. The recently discovered protein inhibitor of activated STAT3 (PIAS3) binds directly to STAT3 and blocks transcriptional activation. In our previous report, we demonstrated that PIAS3 directly interacted with androgen receptor (AR) and affected AR-mediated gene activation. Furthermore, we also showed that AR associated with STAT3 and enhanced its activity. Here, we examined molecular interactions between STAT3, PIAS3, and AR to underline the mechanism of how they regulate each other. AR activation overcame the inhibitory effect on STAT3-mediated transcription by PIAS3. Co-immunoprecipitation experiments revealed that an active form of AR relieved STAT3 from STAT3-PIAS3 complex formation. These results indicate that AR and PIAS3 regulate the STAT3-mediated transcriptional activity by their physical protein-protein competition on STAT3.

Carrier Proteins↗

PubMed2003

Regulation of transforming growth factor-beta signaling by protein inhibitor of activated STAT, PIASy through Smad3.

Smads proteins play a key role in the intracellular signaling of the transforming growth factor (TGF)-beta family of growth factors, which exhibits a diverse set of cellular responses, including cell proliferation and differentiation. In particular, Smad7 acts as an antagonist of TGF-beta signaling, which could determine the intensity or duration of its signaling cascade. In this study we identified a protein inhibitor of activated STAT (signal transducers and activators of transcription), PIASy, as a novel interaction partner of Smad7 by yeast two-hybrid screening using the MH2 domain of Smad7 as bait. The association of Smad7 and PIASy was confirmed using co-expressed tagged proteins in 293T cells. Moreover, we found that other Smads including Smad3 also associated with PIASy through its MH2 domain, and PIASy suppressed TGF-beta-mediated activation of Smad3. PIASy also stimulated the sumoylation of Smad3 in vivo. Furthermore, endogenous PIASy expression was induced by TGF-beta in Hep3B cells. These findings provide the first evidence that a PIAS family protein, PIASy, associates with Smads and involves the regulation of TGF-beta signaling using the negative feedback loop.

Animals↗

PubMed2003

Daxx enhances Fas-mediated apoptosis in a murine pro-B cell line, BAF3.

Daxx has been shown to play an essential in type I interferon (IFN-alpha/beta)-mediated suppression of B cell development and apoptosis. Recently, we demonstrated that Tyk2 is directly involved in IFN signaling for the induction and nuclear translocation of Daxx, which may result in growth arrest and/or apoptosis of B lymphocyte progenitors. To clarify the mechanism of Daxx-mediated apoptosis signaling in B lymphocyte progenitors, here we introduced an efficient suicide switch in a murine pro-B cell line, BAF3, by expressing FK506-binding protein-fused Fas intracellular domain (FKBP-Fas) and Daxx. It allows us to monitor Fas/Daxx-mediated signal by induction of Fas dimerization with the dimerizer drug AP20187. AP20187-mediated Fas dimerization induced not only apoptosis but also Jun N-terminal kinase (JNK) activation. However, AP20187 had no effect on cells expressing either Fas or Daxx only. Furthermore, expression of a JNK inhibitor, the JNK-binding domain of JIP-1, resulted in resistance to AP20187-mediated apoptosis in cells expressing FKBP-Fas and Daxx. These results imply that our novel suicide switch system may provide a powerful tool to delineate or identify the signaling molecules for Daxx-mediated apoptotic machinery in B lymphocyte progenitors through JNK activation.

Animals↗