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Hiroyasu Inoue

Publications and source records attributed to Hiroyasu Inoue.

47 records · Page 3Linked to original sources
PubMed2003

Post-ischemic cyclooxygenase-2 expression is regulated by the extent of cerebral blood flow reduction in non-human primates.

We determined whether up to 24 h of ischemia could induce the expression of cyclooxygenase-2 (COX-2) in the brain of nonhuman primates. Randomized animals were subjected to either a 2 h ischemia (group II; n=3) or a 24 h ischemia (group III; n=3). Three animals in group I served as controls. In group III, regional cerebral blood flow (CBF) and the cerebral glucose metabolic rate (CMRglc) were evaluated using positron emission tomography. Upregulation of COX-2 mRNA expression was observed after 2 h of ischemia, but disappeared by 24 h in the ischemic temporal cortex, in which both CMRglc and CBF were markedly reduced. In the ischemic parietal cortex, where CMRglc was preserved, COX-2 expression persisted even 24 h after ischemia. This study is the first to demonstrate neuronal COX-2 induction within potentially viable hypoperfused brain areas in nonhuman primates.

Animals↗
PubMed2003

15-deoxy-delta 12,14-prostaglandin J2 and laminar fluid shear stress stabilize c-IAP1 in vascular endothelial cells.

Laminar shear stress strongly inhibits vascular endothelial cell apoptosis by unknown mechanisms. We reported that shear stress stimulates endothelial cells to produce 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) by elevating the expression level of lipocalin-type prostaglandin D synthase. To investigate the role of 15d-PGJ2 produced in the vascular wall, we examined the effect of 15d-PGJ2 on endothelial cell apoptosis. We induced apoptosis in human umbilical vein endothelial cells (HUVECs) by growth factor deprivation. 15d-PGJ2 strongly inhibited DNA ladder formation, nuclear fragmentation, and caspase-3-like activity in HUVECs. To elucidate the mechanism by which 15d-PGJ2 inhibits endothelial cell apoptosis, we examined expression of the inhibitor of apoptosis proteins (IAP) cellular-IAP1 (c-IAP1), c-IAP2, x-linked IAP, and survivin in HUVECs. In parallel with the inhibition of apoptosis, 15d-PGJ2 elevated the expression level of c-IAP1 protein in a dose- and time-dependent manner without changing the mRNA level. Laminar shear stress also induced c-IAP1 expression. Chase experiments with the use of cycloheximide revealed that 15d-PGJ2 and shear stress both inhibited the proteolytic degradation of c-IAP1 protein. These results suggested that 15d-PGJ2 inhibits endothelial cell apoptosis through, at least in part, c-IAP1 protein stabilization. This mechanism might be involved in the antiapoptotic effect of laminar shear stress.

Apoptosis↗
PubMed2003

The kinetics of immune reconstitution after cord blood transplantation and selected CD34+ stem cell transplantation in children: comparison with bone marrow transplantation.

The present study compares immune reconstitution after allogeneic cord blood transplantation (CBT) and CD34+ stem cell transplantation (CD34-SCT) with that after bone marrow transplantation (BMT). Eighty-eight children who underwent CBT (20 patients), BMT (58), and CD34-SCT (10) were enrolled, and lymphocytes and T-, B-, and natural killer-lymphocyte subsets were monitored for more than 5 years after transplantation. CBT recipients showed significant ircreases in (1) total lymphocyte counts (P < .001), (2) CD4+/CD8+ cell ratios (P < .01), (3) CD4+ and CD4+CD45RA+ cells (P < .001), (4) CD8+CD11b+ cells (P < .001), and (5) CD19+ and CD19+CD5+ cells (P < .0001) and marked decreases in the frequencies of CD8+ and CD8+CD11b- cells (P < .0001). CD34-SCT recipients showed lower lymphocyte counts in the first 6 months and an emergence of lymphocyte and CD4+CD45RA+ cells at approximately 9 months and 1 year. Both CBT and CD34-SCT recipients showed increased frequencies of CD56+ cells at 1 month (CD34-SCT versus BMT, P < .001) but decreased frequencies after 6 months (CBT versus BMT, P < .001). Lymphoproliferative responses to exogenous interleukin 2 were constantly lower in CBT and CD34-SCT recipients than in BMT recipients. These results suggest that the delay in immune reconstitution after CBT in the early phase was mainly qualitative and related to the immaturity of cells, whereas the delay in CD34-SCT was mainly quantitative in the first several months.

Adolescent↗
PubMed2003

Cyclooxygenase-2 expression associated with spreading depression in a primate model.

The authors previously provided evidence that spreading depression (SD) can be evoked in primates. Cyclooxygenase-2 (COX-2) expression has been found to increase in the rodent cortex undergoing SD, and the authors sought to determine whether this association exists in primate brain. In the present study, neuronal COX-2 expression was induced during SD in the primate cortex. The mean expression ratio of COX-2 messenger RNA in animals with SD was significantly higher than that measured in controls (1.69 vs. 0.5; P = 0.02). Induction of COX-2 in these animals was also detected by human microarray analysis. Results show that, as in rodents, neuronal COX-2 is induced in the primate cortex in response to SD.

Animals↗
PubMed2003

Transcriptional regulation of cyclooxygenase 2 by bradykinin and interleukin-1beta in human airway smooth muscle cells: involvement of different promoter elements, transcription factors, and histone h4 acetylation.

Bradykinin and interleukin-1beta (IL-1beta) induce cyclooxygenase 2 (COX-2) in human airway smooth muscle cells. Here we extended our study to explore the gene transcriptional regulation. By transfection with various COX-2 promoter reporter constructs, we found that the bp -327-to-+59 promoter region was essential for COX-2 gene transcription by bradykinin and IL-1beta and that the cyclic AMP response element (CRE) was critical in bradykinin-induced transcription, whereas nuclear factor IL-6 and CRE and, to a lesser extent, nuclear factor-kappaB (NF-kappaB) were involved in IL-1beta-induced transcription. An electrophoretic mobility shift assay revealed that both bradykinin and IL-1beta elicited CRE-binding protein-1 (CREB-1) binding, and IL-1beta also elicited CCAAT/enhancer-binding protein beta and NF-kappaB binding to their respective elements in the COX-2 promoter. These transcription factors were associated with the COX-2 promoter, which was dynamically linked to different patterns of histone H4 acetylation by bradykinin and IL-1beta, as demonstrated by chromatin immunoprecipitation. We also revealed that endogenous prostaglandin E(2) was critical in bradykinin-induced COX-2 transcription initiation and involved in IL-1beta-induced COX-2 transcription at a latter stage. Our result provide the first evidence that COX-2 transcriptional regulation by different stimuli involves different promoter elements and transcription factors and is associated with chromatin remodeling after selective histone H4 acetylation in a stimulus-specific manner.

Acetylation↗
PubMed2002

Transcriptional and posttranscriptional regulation of cyclooxygenase-2 expression by fluid shear stress in vascular endothelial cells.

OBJECTIVE: Fluid shear stress induces cyclooxygenase (COX)-2 gene expression in vascular endothelial cells. We investigated the underlying mechanism of this induction. METHODS AND RESULTS: Exposure of human umbilical vein endothelial cells to laminar shear stress in the physiological range (1 to 30 dyne/cm2) upregulated the expression of COX-2 but not COX-1, a constitutive isozyme of COX. The expression of COX-2 mRNA began to increase within 0.5 hour after the loading of shear stress and reached a maximal level at 4 hours. Roles of the promoter region and the 3'-untranslated region in the human COX-2 gene were evaluated by the transient transfection of luciferase reporter vectors into bovine arterial endothelial cells. Shear stress elevated luciferase activity via the region between -327 and 59 bp. Mutation analysis indicated that cAMP-responsive element (-59/-53 bp) was mainly involved in this response. On the other hand, shear stress selectively stabilized COX-2 mRNA. Moreover, shear stress elevated luciferase activity when a 3'-untranslated region of COX-2 gene containing 17 copies of the AUUUA mRNA instability motif was inserted into the vector. CONCLUSIONS: Transcriptional activation and posttranscriptional mRNA stabilization contribute to the rapid and sustained expression of COX-2 in response to shear stress.

3' Untranslated Regions↗
PubMed2002

Growth stimulation and epidermal growth factor receptor induction in cyclooxygenase-overexpressing human colon carcinoma cells.

Recent epidemiological and experimental investigations suggest a close relationship between cyclooxygenase (COX) and pathogenesis of colorectal cancer. There are two isoforms, COX-1 and COX-2, which differ in physiological functions and distribution. This study is to investigate the possible roles of both isoforms in the proliferation of colon carcinoma cells. A human colon carcinoma cell line, COLO 320DM, was transfected with an eukaryotic expression vector (pEF-BOS) carrying cDNA of either COX-1 or COX-2. Both COX-1 and COX-2-expressing cells exhibited a similar enzyme activity, 8-10 nmol/10 min/mg of protein. Growth rates of both COX-expressing cells were increased by about 2 fold as compared with mock-transfected cells. The stimulated growth of the COX-expressing cells was confirmed by the increased DNA synthesis as assessed by [3H]thymidine incorporation. Furthermore, expression of epidermal growth factor receptor (EGFR) was markedly increased in the COX-expressing cells as examined by reverse transcriptase-polymerase chain reaction (RT-PCR). A COX inhibitor, indomethacin, suppressed the stimulated growth, increased DNA synthesis and induction of epidermal growth factor receptor in the COX-1 and COX-2-transfected cells. These results suggest that not only COX-2 but COX-1 is involved in the proliferation of human colon carcinoma cells through the induction of EGFR.

Cell Division↗
PubMed2002

The generation of immunocompetent dendritic cells from CD34+ acute myeloid or lymphoid leukemia cells.

The ability of CD34+ leukemic cells to differentiate to dendritic cells (DCs) was investigated in 18 acute myeloid leukemia (AML) and 4 lymphoid leukemia (ALL) patients. The generation of DCs was determined by the expression of DC-associated CD1a or CD83 (more than 30%) with costimulatory molecules, by CD80 antigens (>20%), and by the exhibition of allostimulatory activity. In the AML patients, allostimulatory mature DCs were generated from 3 of 9 M0 or M1, 2 of 5 M2,2 of 4 M4 or M5, and 3 of 4 ALL (L2) cases. In total, DCs were more efficiently induced from cases expressing over 75% of CD34+ among whole bone marrow mononuclear cells (8 of 12), compared with those under 75% (2 of 10; P < .05). B-cell (CD19), natural killer (NK)-cell (CD56), or T-cell (CD7) lineage markers, which were aberrantly expressed on the blasts, were rarely found on leukemic DCs at the end of the culture period, and myeloid (CD13, CD33), not lymphoid (CD10), markers were shown on ALL-derived DCs. In Philadelphia chromosome-positive ALL or AML patients with t (8;21), DCs were confirmed to be of leukemic origin by fluorescence in situ hybridization analysis.

Acute Disease↗
PubMed2002

Human umbilical cord blood NK T cells kill tumors by multiple cytotoxic mechanisms.

Natural killer (NK) T cells are restricted by CD1d and play an important role in the rejection of malignant tumors, but how kill these tumors is unclear. To investigate this, we cultured Valpha24+CD4+ NK T cells in human umbilical cord blood, which was enriched by immunomagnetic beads. In short-term (4 h) cytotoxicity assays, the NK T cells could kill only those targets expressing CD1d. In longer cytotoxicity assays (20 h), however, the NK T cells were able to kill all the tumors, regardless of CD1d expression. When each of the perforin, Fas-FasL, and TNF-alpha cytotoxic mechanisms were blocked, it was apparent that perforin killing dominated in both the short- and long-term assays. In the short-term assay, perforin killing required that the targets expressed CD1d, but killing was more efficient if Fas was present because then the Fas-FasL mechanism was also used. Thus, cells that lacked Fas and CD1d and were not killed in the 4-h assay, were instead lysed in 20-h assay through a combination of perforin and TNF-alpha killing. NK T cells can kill tumor targets by perforin, Fas-FasL, and TNF-alpha mechanisms. TNF-alpha killing requires longer contact between effectors and targets, suggesting that TNF-alpha acts by enhancing perforin killing.

Antigens, CD1↗
PubMed2001

Killing activity of human umbilical cord blood-derived TCRValpha24(+) NKT cells against normal and malignant hematological cells in vitro: a comparative study with NK cells or OKT3 activated T lymphocytes or with adult peripheral blood NKT cells.

PURPOSE: We aimed to determine the effects of human umbilical cord blood (UCB)-derived natural killer T (NKT) cells as immunological effectors against hematological malignancies, as well as auto- or allo-dendritic cells (DCs) or EB transformed cell lines (EBCLs). MATERIALS: TCRValpha24(+) Vbeta11(+) UCB- or PB-NKT cells were isolated by sorting and activated by alpha-galactosylceramide-pulsed autologous DCs. UCB-NK cells were induced from CD34(+) cells by stem cell factor plus IL-15. UCB-T cells were primarily activated by anti-CD3 monoclonal antibody. All those effectors were cultured with IL-2 (100 U/ml), and their cytotoxic activities were evaluated by (51)Cr-release assay. UCB-NKT cells were cultured with IL-12, IL-18 or higher dose of IL-2 (1000 U/ml), and again tested for the cytotoxicity against selected targets. RESULTS: UCB-NKT cells exhibited a pattern of killing activity against various hematological malignancies similar to that of UCB-NK cells, but could not kill K562, which was a vulnerable target for NK cells. The level of activity was quite similar to that of PB-NKT cells. In contrast, OKT-3-activated UCB-T lymphocytes showed a stronger and wider spectrum of killing compared with UCB-NK or NKT cells. IL-12, IL-18 or a higher dose of IL-2 upregulated the activity; however several targets, including fresh leukemic cells, still remained resistant. NKT cells killed auto- or allo-DCs at a level similar to that of T cells, but could not kill allo-EBCLs, which were efficiently killed by T cells. While NK cells showed only marginal or no killing against DC or EBCLs. DISCUSSION: The anti-cancer activity of human NKT cells depends on the concentrations or the combination of Th1-cytokines. Basically, those cells might not be contributing to the immune surveillance of hematological malignancies, as shown by a relatively low cytotoxicity against malignant cells, together with the quite strong killing against auto-DCs.

Antigens, CD1↗