Biomedical subjects

Tadashi Matsuda

Publications and source records attributed to Tadashi Matsuda.

At least 73 records · Page 4Linked to original sources

PubMed2003

Involvement of heat-shock protein 90 in the interleukin-6-mediated signaling pathway through STAT3.

Interleukin-6 (IL-6) is a multifunctional cytokine playing roles in the immune system, hematopoiesis, and acute phase reactions. IL-6 also regulates the growth of various types of human malignant tumors. Here we demonstrate that IL-6-induced gene expression was suppressed by a specific heat-shock protein 90 (Hsp90) inhibitor, geldanamycin (GA) in human hepatoma Hep3B cells. GA also suppressed the IL-6-induced activation of signal transducer and activator of transcription 3 (STAT3) in a human embryonic kidney carcinoma 293T cells. This inhibitory effect of GA on STAT3 activation was reversed by overexpression of Hsp90. Furthermore, Hsp90 directly bound to STAT3 via its N-terminal region, which interacted with GA. We provide evidence that the action of GA on IL-6 functions was due to the inhibition of direct physical interactions between STAT3 and Hsp90, which represents a novel role of Hsp90 in the IL-6 signaling pathways.

Benzoquinones↗

PubMed2003

STAP-2/BKS, an adaptor/docking protein, modulates STAT3 activation in acute-phase response through its YXXQ motif.

As a c-fms-interacting protein, we cloned a novel adaptor molecule, signal-transducing adaptor protein-2 (STAP-2), which contains pleckstrin homology- and Src homology 2-like (PH and SRC) domains and a proline-rich region. STAP-2 is structurally related to STAP-1/BRDG1 (BCR downstream signaling-1), which we had cloned previously from hematopoietic stem cells. STAP-2 is a murine homologue of a recently identified adaptor molecule, BKS, a substrate of BRK tyrosine kinase. STAP-2 was tyrosine-phosphorylated and translocated to the plasma membrane in response to epidermal growth factor when overexpressed in fibroblastic cells. To define the function of STAP-2, we generated mice lacking the STAP-2 gene. STAP-2 mRNA was strongly induced in the liver in response to lipopolysaccharide and in isolated hepatocytes in response to interleukin-6. In the STAP-2(-/-) hepatocytes, the interleukin-6-induced expression of acute-phase (AP) genes and the tyrosine-phosphorylation level of STAT3 were reduced specifically at the late phase (6-24 h) of the response. These data indicate that STAP-2 plays a regulatory role in the AP response in systemic inflammation. STAP-2 contains a YXXQ motif in the C-terminal region that is a potential STAT3-binding site. Overexpression of wild-type STAP-2, but not of mutants lacking this motif, enhanced the AP response element reporter activity and an AP protein production. These data suggest that STAP-2 is a new class of adaptor molecule that modulates STAT3 activity through its YXXQ motif.

Acute-Phase Reaction↗

PubMed2003

Surgical outcome of laparoscopic radical prostatectomy: summary of early multiinstitutional experience in Japan.

BACKGROUND: Because laparoscopic radical prostatectomy requires significant laparoscopic expertise, it needs to be evaluated critically before being accepted as a standard therapeutic option for localized prostate cancer. METHODS: A total of 148 men diagnosed as having clinically resectable prostate cancer underwent laparoscopic radical prostatectomy at seven different institutions in Japan. Early biochemical and oncological outcomes were investigated. RESULTS: Policies underlying the selection of laparoscopic radical prostatectomy did not appear to be consistent among the participating institutions. Pathologically organ-confined disease was found in 64.0% of the patients who had undergone neoadjuvant therapy and in 77.2% of those who had not. Positive surgical margins were found in 36.0% and 34.1%, respectively, of the specimens. The most common site was the apex, which accounted for 77.8% of positive margins in patients who had undergone neoadjuvant therapy and 50.0% in those who had not. Seven patients have experienced biochemical failure at a median follow-up of 9.0 months. No clinical progression has been reported. CONCLUSIONS: Continuing improvements in each step of laparoscopic radical prostatectomy, especially apical dissection, should be sought as we pursue the goal of still better oncological outcomes. A systematic approach and therapeutic guidelines should help to reduce the learning curve for competent performance of this procedure.

Aged↗

PubMed2003

Limitin, an interferon-like cytokine, transduces inhibitory signals on B-cell growth through activation of Tyk2, but not Stat1, followed by induction and nuclear translocation of Daxx.

OBJECTIVE: Limitin, an interferon-like cytokine, suppresses B lymphopoiesis through ligation of the interferon-alpha/beta (IFN-alpha/beta) receptor. The aim of this study was to examine the intracellular signal transduction pathways activated by limitin. MATERIALS AND METHODS: The effects of limitin on cell growth, the activation of Jak kinase and Stat proteins, and the induction of interferon regulatory factor-1 (IRF-1) and Daxx were examined using the mouse pre-B-cell line 18.81, wild-type, and Tyk2-deficient mouse bone marrow cells. In addition, the change of localization of the Daxx protein after limitin treatment in wild-type and Tyk2-deficient mice was examined. RESULTS: Limitin phosphorylates Tyk2, Jak1, Stat1, and Stat2 and rapidly induces IRF-1 mRNA production. Phosphorylation of Stat1 by limitin is partially dependent on Tyk2. Suppression of B-cell growth by limitin, however, is severely impaired in the absence of Tyk2, whereas it is unaffected by the absence of Stat1. Limitin also induces the expression and nuclear translocation of Daxx, which is essential for IFN-alpha-induced inhibition of B-lymphocyte development. The absence of Tyk2 abrogates this induction of Daxx expression and nuclear translocation. CONCLUSIONS: Limitin suppresses B-cell growth through activation of Tyk2, resulting in the up-regulation and nuclear translocation of Daxx. This limitin-mediated signaling pathway does not require Stat1.

Active Transport, Cell Nucleus↗

PubMed2003

Intracellular signal transduction of interferon on the suppression of haematopoietic progenitor cell growth.

Interferon (IFN)-alpha and IFN-gamma suppress the growth of haematopoietic progenitor cells. IFN-alpha activates Janus kinase-1 (Jak1) and Tyrosine kinase-2 (Tyk2), followed by the phosphorylation of the signal transducers and activators of transcription, Stat1 and Stat2. IFN-gamma activates Jak1 and Jak2, followed by the activation of Stat1. Activated Stats bind the promoter regions of IFN-inducible genes. We evaluated the role of Tyk2 and Stat1 in the IFN-mediated inhibition of haematopoietic progenitor cell growth. While IFN-alpha (1000 U/ml) suppressed the number of granulocyte-macrophage colony-forming units (CFU-GM) or erythroid burst-forming units (BFU-E) from wild-type mouse bone marrow cells, this suppression was partially inhibited by a deficiency in Tyk2 and completely inhibited by a deficiency in Stat1. High levels of IFN-alpha (10,000 U/ml) suppressed the CFU-GM or BFU-E obtained from Stat1-deficient mice, but did not suppress this growth in cells from Tyk2-deficient mice. Stat1 was phosphorylated by IFN-alpha in Tyk2-deficient cells, although the level of phosphorylation was weaker than that observed in wild type mice. Thus, the inhibitory signal on haematopoietic progenitor cells mediated by IFN-alpha may be transduced by two signalling pathways, one regulated by Tyk2 and the other dependent on Stat1. IFN-gamma also suppressed the number of CFU-GM or BFU-E, and this pathway was mediated by IFN-gamma in a Stat1-dependent manner, independently of Tyk2.

Animals↗

PubMed2003

Morbidity of laparoscopic radical prostatectomy: summary of early multi-institutional experience in Japan.

AIM: Laparoscopic radical prostatectomy is being evaluated throughout the world. The aim of the present study is to report early multi-institutional experience of the procedure in Japan. METHODS: A total of 148 men who were diagnosed with clinically localized prostate cancer underwent laparoscopic radical prostatectomy at seven different institutions in Japan. Early complications (within 30 days postoperatively) and postoperative convalescence were reviewed retrospectively. The median age of patients was 68.0 years (range, 51-80). RESULTS: The median operative time was 403 minutes (range, 167-925; average, 427). Blood loss ranged from 50 to 5000 mL (median, 540; average, 856). A total of 66 complications were reported in 55 patients (37.2%). Intraoperative complications were noted in 25 of 148 patients (16.9%): 10 rectal injuries (6.8%); five bladder injuries (3.4%); five cases of subcutaneous emphysema (3.4%); two intestinal injuries (1.4%); one major vessel injury (0.7%); one ureteral injury (0.7%); and one obturator nerve injury (0.7%). Overall, 16 of 148 patients (10.8%) required open conversion or postoperative open surgical repair. The most common postoperative complications were anastomotic leakage (6.8%), wound-related complications (4.7%) and perineal pain (4.7%). The bladder catheter was removed on day 7 or earlier in 73 cases (49.3%). The median time to ambulation was 1 day (mean 1.4, range 1-5). Oral intake was started on postoperative day 1 in 67 patients (45.2%) and on postoperative day 2 in 65 (43.9%). CONCLUSION: Although laparoscopic radical prostatectomy is technically demanding, reduced blood loss and shorter convalescence periods can be expected from the procedure. Surgeons should be aware of the disturbingly high morbidity rate related to early experience. By mastering laparoscopic skills and sharing knowledge, surgeons could reduce the impact of the learning curve required to complete this procedure competently.

Aged↗

PubMed2002

Cutting edge: tyk2 is required for the induction and nuclear translocation of Daxx which regulates IFN-alpha-induced suppression of B lymphocyte formation.

IFN-alpha inhibits B lymphocyte development, and the nuclear protein Daxx has been reported to be essential for this biological activity. We show in this study that IFN-alpha inhibits the clonal proliferation of B lymphocyte progenitors in response to IL-7 in wild-type, but not in tyk2-deficient, mice. In addition, the IFN-alpha-induced up-regulation and nuclear translocation of Daxx are completely abrogated in the absence of tyk2. Therefore, tyk2 is directly involved in IFN-alpha signaling for the induction and translocation of Daxx, which may result in B lymphocyte growth arrest and/or apoptosis.

Active Transport, Cell Nucleus↗

PubMed2002

The nuclear isoform of protein-tyrosine phosphatase TC-PTP regulates interleukin-6-mediated signaling pathway through STAT3 dephosphorylation.

In the previous study, we demonstrated that the nuclear isoform of T-cell protein-tyrosine phosphatase (TC-PTP) dephosphorylated and deactivated signal transducer and activator of transcription 5a (STAT5a) and STAT5b, thereby negatively regulating prolactin (PRL)-mediated signaling pathway. In this study, we examined the involvement of the nuclear isoform of TC-PTP in interleukin-6 (IL-6)-mediated signaling pathway. IL-6 is a multifunctional cytokine that plays important roles in the immune system, hematopoiesis, and acute phase reactions, and has also implicated in IL-6-related diseases. Here, we demonstrate that IL-6-induced tyrosine-phosphorylation and activation of STAT3 were suppressed by overexpression of the nuclear isoform of TC-PTP in 293T cells. Tyrosine-phosphorylated STAT3 directly interacted with a substrate-trapping mutant of TC-PTP. Furthermore, retrovirus-mediated overexpression of the nuclear isoform of TC-PTP suppressed the IL-6-induced growth arrest of myeloid leukemia M1 cells. Endogenous TC-PTP complexed with STAT3 in the nucleus of M1 cells. These results strongly suggest that the nuclear isoform of TC-PTP may serve as a negative regulator of IL-6-mediated signaling pathway.

Acute-Phase Proteins↗

PubMed2002

Lymphoid enhancer-binding factor-1 binds and activates the recombination-activating gene-2 promoter together with c-Myb and Pax-5 in immature B cells.

The recombination-activating gene (RAG)-1 and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of Ag receptor genes. We studied the regulation of murine RAG-2 promoter and revealed that -41/-17 RAG-2 promoter region, which was indispensable for the RAG-2 promoter activity in B cell lines, contained binding sites for lymphoid enhancer-binding factor-1 (LEF-1), c-Myb, and Pax-5. We showed that these three transcription factors bound the promoter region in vitro and in vivo. Cotransfection assays using a human embryonic kidney cell line (293T) showed that LEF-1, c-Myb, and Pax-5 cooperatively activated the RAG-2 promoter, via their synergistic DNA binding. We also showed that LEF-1, c-Myb, and Pax-5 physically interact in the cells. Finally, we demonstrated that a dominant-negative LEF-1 protein, which lacks the binding site for beta-catenin, suppressed the RAG-2 promoter activity as well as the endogenous RAG-2 expression in a pre-B cell line (18.81). These results suggest that LEF-1/beta-catenin complex regulates the RAG-2 promoter activation in concert with c-Myb and Pax-5 in immature B cells. The link between LEF-1/beta-catenin and Wnt signaling in B lineage cells will be discussed.

5' Untranslated Regions↗

PubMed2002

Characterization of chromatin structure and enhancer elements for murine recombination activating gene-2.

Recombination-activating genes (RAGs) play a critical role in V(D)J recombination machinery and their expression is specifically regulated during lymphocyte ontogeny. To elucidate the molecular mechanisms regulating murine RAG-2 expression, we examined a chromatin structure of 25-kb DNA segment adjacent to murine RAG-2 by analyzing DNase I hypersensitive (HS) sites. In a RAG-2-expressing murine pre-B cell line, three lymphoid cell-specific HS sites (HS1, HS2, and HS3) were identified. Among these HS sites, one HS site (HS3) that locates in the RAG-2 promoter was associated only with RAG-2-expressing cell lines. Using the transient enhanced green fluorescence protein reporter gene assays, we identified two enhancer elements in the 5'-upstream region of RAG-2 that corresponded to HS1 and HS2. One of the enhancer elements (D3) exhibited enhancer activity only in the lymphoid cell lines. Analysis of the transgenic mice carrying the enhanced green fluorescence protein-reporter gene linked with D3 revealed that D3 activated the reporter gene-expression in the primary lymphoid tissues, but not in the secondary lymphoid tissues or nonlymphoid tissues. D3 was active in CD4(-)CD8(-), but not in CD4(+)CD8(+) or CD4(+)CD8(-) thymocytes in the thymus, and also active in B220(+)IgM(-), but not in B220(+)IgM(+), cells in the bone marrow. Finally, our data suggested that C/EBP may bind to the D3 enhancer and function as one of the transcription factor(s) responsible for the enhancer activity. These results show that the tissue- and stage-specific expression of murine RAG-2 is regulated by alteration of the chromatin structure as well as cis-regulatory enhancer elements.

3T3 Cells↗

PubMed2002

Partial impairment of interleukin-12 (IL-12) and IL-18 signaling in Tyk2-deficient mice.

Tyk2 is activated in response to interleukin-12 (IL-12) and is essential for IL-12-induced T-cell function, including interferon-gamma (IFN-gamma) production and Th1 cell differentiation. Because IL-12 is a stimulatory factor for natural killer (NK) cell-mediated cytotoxicity, we examined whether tyk2 is required for IL-12-induced NK cell activity. IL-12-induced NK cell activity in cells from tyk2-deficient mice was drastically reduced compared to that in cells from wild-type mice. IL-18 shares its biologic functions with IL-12. However, the molecular mechanism of IL-18 signaling, which activates an IL-1 receptor-associated kinase and nuclear translocation of nuclear factor-kappaB, is different from that of IL-12. We next examined whether biologic functions induced by IL-18 are affected by the absence of tyk2. NK cell activity and IFN-gamma production induced by IL-18 were reduced by the absence of tyk2. Moreover, the synergistic effect of IL-12 and IL-18 for the production of IFN-gamma was also abrogated by the absence of tyk2. This was partially due to the absence of any up-regulation of the IL-18 receptor treated with IL-12, and it might suggest the presence of the cross-talk between Jak-Stat and mitogen-activated protein kinase pathways in cytokine signaling.

Animals↗

PubMed2002

Vasoactive intestinal peptide (VIP) enhances the cell motility of androgen receptor-transfected DU-145 prostate cancer cells (DU-145/AR).

We established a clonal DU-145 prostate cancer cell line (DU-145/AR) stably transfected with androgen receptor (AR) cDNA and investigated the expression of type 1 vasoactive intestinal peptide (VIP) receptor (VIP1R) and type 2 VIP receptor (VIP2R) mRNA in these cells by reverse transcriptase-polymerase chain reaction analysis and the effect of VIP on the invasion and the haptotactic migration of these cells. DU-145/AR cells constitutively expressed both VIP1R and VIP2R mRNA, but the parent DU-145 cells did not. VIP increased the invasive capacity of DU-145/AR cells. VIP also enhanced the haptotactic migration of these cells to fibronectin. However, the growth of these tumor cells was not affected by VIP at any concentrations used in this study. These results indicate that VIP may play a role in the regulation of the invasion of prostate cancer.

Blotting, Western↗

PubMed2002

Cooperative binding of c-Myb and Pax-5 activates the RAG-2 promoter in immature B cells.

The recombination activating gene-1 (RAG-1) and RAG-2 are expressed specifically in immature lymphoid cells undergoing the recombination of antigen receptor genes. The regulation of murine RAG-2 promoter was studied and it was revealed that the -41/-17 RAG-2 promoter region, which is conserved between humans and mice, was indispensable for the RAG-2 promoter activity in B-cell lines. The region contained 2 cis elements that bound c-Myb and Pax-5. Mutation in the c-Myb-binding site in the promoter reduced the promoter activity in B-cell lines. Cooperative activation of the RAG-2 promoter was seen by a combination of c-Myb and Pax-5 in a human embryonic kidney cell line (293T), via their synergistic DNA-binding. Deletion experiments showed that the C-terminus of c-Myb was responsible for their interaction. Furthermore, the dominant-negative c-Myb mutant suppressed the activation of the RAG-2 promoter in a pre-B-cell line as well as in 293T cells. These results suggest that cooperative binding of c-Myb and Pax-5 to the RAG-2 promoter is one of the mechanisms to direct the restricted expression of the RAG-2 in immature B cells.

Animals↗

PubMed2002

KUR-1246, a novel beta(2)-adrenoceptor agonist, as a tocolytic agent.

OBJECTIVE: To examine the effects of KUR-1246 on oxytocin-induced uterine contractions, the cardiovascular system, and general metabolism of pregnant sheep and their fetuses. METHODS: At 123-125 days' gestation, ewes (n = 8) were infused with oxytocin (1.0 mU/kg/minute) to induce uterine contractions. One hour later, KUR-1246 was infused for 3 consecutive hours beginning at a dose of 0.001 microg/kg/minute for 30 minutes and increasing stepwise every 30 minutes to 0.3 microg/kg/minute in the KUR-1246 group (n = 4). The control received saline instead (n = 4). Statistical comparisons of changes with time in the physiologic parameters between the two groups were carried out (analysis of variance). RESULTS: KUR-1246 suppressed oxytocin-induced uterine contractions more than 90% at doses over 0.03 microg/kg/minute. Significant differences between the two groups were found at high doses over 0.03 microg/kg/minute for the following parameters: maternal heart rate, diastolic blood pressure, mean blood pressure, base excess, blood K(+), blood lactate, plasma glucose, plasma insulin, plasma nonesterified fatty acid levels, and fetal plasma glucose and plasma insulin levels. CONCLUSION: KUR-1246 significantly inhibited oxytocin-induced uterine contractions at doses over 0.03 microg/kg/minute and showed reduced cardiovascular and metabolic side effects compared with ritodrine hydrochloride studied earlier in pregnant sheep.

Acetamides↗

PubMed2002

Retroperitoneoscopic partial nephrectomy using microwave coagulation for small renal tumors.

OBJECTIVES: The outcome of laparoscopic partial nephrectomy using a microwave tissue coagulator for treatment of small renal tumors was studied. PATIENTS AND METHODS: From June 1999 to May 2001, eight patients with small renal tumors of less than 5.0cm in diameter (1.0-5.0cm, T1N0M0) underwent retroperitoneoscopic partial nephrectomy. To control bleeding during the partial nephrectomy, the renal parenchyma around the tumor was coagulated using a microwave tissue coagulator with a needle of 1.5cm length. The tumor was circumscribed within the coagulated area with 8-13 punctures of the coagulation needle, and partial nephrectomy was performed using scissors and bipolar forceps. RESULTS: All eight patients successfully underwent the procedure retroperitoneoscopically. The average operative time was 295 minutes and the average blood loss was 129ml. Three patients showed urine leakage from the renal calyces, which was controlled by suturing retroperitoneoscopically. In two patients, the surgical margin was revealed to be positive for renal cell carcinoma by frozen section pathology and additional resection was performed in these individuals. The patients were discharged from the hospital with almost full convalescence on day 10 on average. Within the mean follow-up period of 10.4 months, no recurrence was found when examined with computer tomography (CT) using contrast media. As a complication, one patient experienced a decrease in function of the operated kidney caused by unknown reason. CONCLUSION: Retroperitoneal partial nephrectomy using a microwave tissue coagulator is useful for treatment of small renal tumors located at the peripheral area of the kidney. Bleeding from the renal parenchymal incision site is well controlled without occlusion of the renal artery with additional use of a bipolar coagulator, when necessary. Further experience and long-term follow-up are mandatory however, to establish the usefulness of this technique.

Adult↗

PubMed2002

The regulation of DNAse activities in subcellular compartments of activated thymocytes.

Thymocytes expressing self-reactive T-cell receptors (TCR) are eliminated in the thymus through a TCR-mediated signal. This cell death signal (negative selection) generates nuclear morphological change and DNA fragmentation in thymocytes. However, the pathway leading to DNA fragmentation of thymocytes following TCR engagement remains obscure. In this study, we investigated the localization and function of caspase-activated DNAse (CAD) and its inhibitor (ICAD) in thymocytes prior to or after in vivo TCR stimulation. We showed that CAD and ICAD are co-localized in microsome, nuclei and cytosol in unstimulated thymocytes. Following in vivo TCR engagement, ICAD located in cytosol and microsome was degraded and the resulting activated CAD induced chromosomal DNA fragmentation. CAD present in cytosol and microsome of unstimulated thymocytes was activated by recombinant caspase-3, and microsomal CAD was released to the cytosol. These results demonstrate that TCR engagement of thymocytes induces caspase-3-dependent activation of CAD localized in both cytosol and microsome, leading to DNA fragmentation in harmony.

Animals↗

PubMed2002

Endoscopic partial cystectomy for bladder leiomyoma using retroperitoneoscopic and transurethral procedures.

Retroperitoneoscopic partial cystectomy was performed to remove a leiomyoma in the right wall of the bladder in a 58-year-old man. The tumor was initially circumscribed with a mucosal incision using a transurethral resectoscope, and once the bladder wall had been penetrated with the resectoscope, the remaining procedures were performed retroperitoneoscopically. The bladder wall was closed using a retroperitoneoscopic suturing technique. Endoscopic partial cystectomy using both a transurethral incision and a retroperitoneoscopic resection is technically feasible in the treatment of small bladder tumors.

Cystectomy↗

PubMed2002

Retroperitoneoscopic nephrectomy for juxtaglomerular cell tumor.

We present a case of juxtaglomerular cell tumor (JGCT) in a 20-year-old woman. She presented with hypertension and elevated plasma renin activity. Computed tomography without enhancement by contrast medium detected a tumor at the center of the left kidney. Retroperitoneoscopic left nephrectomy was performed and postoperatively her blood pressure and plasma renin activity returned to normal. This is the first report of retroperitoneoscopic nephrectomy performed for a JGCT.

Adenocarcinoma↗