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M Hirashima

Publications and source records attributed to M Hirashima.

At least 19 recordsLinked to original sources
PubMed2005

Retinoic acid-inducible gene-I is induced by interleukin-1beta in cultured human gingival fibroblasts.

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box family protein, and details of its biological function are not known. We have studied the mechanism of the interleukin-1beta (IL-1beta)-induced RIG-I expression in human gingival fibroblasts in culture. We also addressed the possibility of enhanced expression of COX-2, RANTES and galectin-9 in fibroblasts overexpressed RIG-I. We stimulated cultured human gingival fibroblasts with IL-1beta and examined the expression of RIG-I mRNA and protein by reverse transcriptase-mediated polymerase chain reaction and Western blot analysis. The effect of cycloheximide, a protein synthesis inhibitor, on the IL-1beta-induced expression of RIG-I was examined. The expression of COX-2, RANTES, galectin-9 and monocyte chemoattractant protein-1 in gingival fibroblasts transfected with RIG-I cDNA was also examined. IL-1beta stimulated the expressions of mRNA and protein for RIG-I, in cultured fibroblasts, in a time- and concentration-dependent manner. Cycloheximide did not suppress the IL-1beta-induced RIG-I expression. Introduction of RIG-I cDNA into fibroblasts resulted in enhanced expression of COX-2 mRNA, and slightly enhanced the expression of mRNA for RANTES and galectin-9. In contrast, RIG-I overexpression did not alter the level of mRNA for monocyte chemoattractant protein-1. We conclude that IL-1beta stimulates RIG-I expression in human gingival fibroblasts.

Blotting, Western↗
PubMed2004

Long term prognosis of children born to lupus patients.

OBJECTIVE: To determine the long term prognosis of children of patients with systemic lupus erythematosus (SLE). METHODS: Children of patients with SLE were invited to attend our clinic for physical examination and laboratory tests. A total of 195 children (aged 4 months to 26 years; male = 82, female = 113) were examined in 1991, 1995, 1997, and 1998. RESULTS: Two cases were diagnosed as SLE at the first visit and were excluded from the second visit. A significantly higher percentage (52/195 (27%)) of patients were positive for antinuclear antibodies (ANA) at a cut off serum dilution of 1/40 compared with controls (4/57 (7%)). ANA were detected more frequently in female subjects than in men (p<0.05). Forty four subjects were examined on more than two occasions. Nine of the 10 patients who were positive for ANA at the second visit were girls aged 4-8 years. The incidence of anti-DNA and antiphospholipid antibodies in children of patients with SLE was similar to that in the controls. CONCLUSIONS: The finding that children, especially girls, born to maternal lupus patients had a high positive rate for ANA suggests that a genetic factor is involved in SLE pathogenesis. Longitudinal observation of these patients may provide important clinical information and clues to the pathogenesis of SLE.

Adolescent↗
PubMed2004

Expression and activity analyses of CTLA4 in peripheral blood lymphocytes in systemic lupus erythematosus patients.

The objective of this study was to determine the expression and activity of CTLA4 in T-cells of systemic lupus erythematosus (SLE) patients. Expression of CTLA4 on freshly isolated peripheral blood T-cells was evaluated in 33 SLE patients and 25 controls using flow cytometry. The T-cells from 19 SLE patients and 22 controls were stimulated and cultured with Chinese hamster ovary cells expressing CD80 (CHO-CD80) or with CHO cells. T-cell proliferation was determined with [3H] thymidine incorporation (CPM), and the inhibitory effect of CTLA4 on T-cell proliferation was evaluated by the ratio of CPM for T-cells with CHO-CD80 cells to that of T-cells with CHO cells (the CHO-CD80/CHO ratio). Intracellular CTLA4 expression in freshly isolated peripheral blood T-cells was significantly higher in SLE patients than the controls (P < 0.05), but there was no correlation with clinical features or disease activity. The CHO-CD80/CHO ratio of SLE patients was significantly higher than that of the controls (P < 0.05). Among SLE patients, the CHO-CD80/CHO ratio of patients with lupus nephritis was significantly higher than that of patients without lupus nephritis (P < 0.05). In conclusion, our data suggest that CTLA4 expression is not impaired in SLE patients, but there is a possibility of decreased inhibitory effect of CTLA4 involved in the pathogenesis of SLE.

Adolescent↗
PubMed2003

Involvement of CD4 D3-D4 membrane proximal extracellular domain for the inhibitory effect of oxidative stress on activation-induced CD4 down-regulation and its possible role for T cell activation.

During antigen presentation, CD4 functions to stabilize T cell receptor (TCR)-class II MHC interactions and coordinate Ag-induced T cell activation signals. These activation signals cause CD4 down-regulation, presumably acting to optimize T cell activation. We previously reported that oxidative stress interferes with activation-induced CD4 down-regulation in T cells. In this study, we have further investigated inhibition of CD4 down-regulation by oxidative stress and its role for T cell activation. A construct comprised of the mouse FcgammaRIIB extracellular domain and the transmembrane/cytoplasmic domains of human CD4 (FcgammaR/CD4) was expressed in a human T cell line. Oxidant actually potentiated down-regulation of the FcgammaR/CD4 chimera and induced Lck dissociation from both CD4 and FcgammaR/CD4, which is a crucial intracellular process for activation-induced CD4 down-regulation, suggesting a critical role of CD4 ectodomain in the inhibition of CD4 down-regulation by oxidative stress. Furthermore, insertion of CD4 D3-D4 membrane proximal extracellular region between FcgammaR extracellular domain and CD4 transmembrane/cytoplasmic domains in FcgammaR/CD4 chimera made this molecule behave like native CD4 molecule under oxidative stress condition. These data imply that the inhibitory effect of oxidative stress on CD4 down-regulation is executed via D3-D4 domain of CD4 ectodomain. As to its role for T cell activation, CD4 coaggregation with CD3 under the oxidative conditions enhanced activation signal induced by CD3 aggregation. Our results demonstrate that Ag-induced T cell activation which is normally concomitant with CD4 down-regulation may be disturbed through the aberrant regulation of CD4 expression by oxidative stress.

Amino Acid Sequence↗
PubMed2001

Interleukin-1beta stimulates galectin-9 expression in human astrocytes.

Galectin-9 is an eosinophil chemoattractant produced by activated T lymphocytes. We have addressed expression of galectin-9 in normal human astrocytes in culture. Expression of galectin-9 mRNA and protein were examined by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunofluorescent staining. Interleukin-1beta (IL-1beta) was found to enhance the galectin-9 expression in time- and concentration-dependent manners. Galectin-9 protein was detected in the membrane fraction, 105 000 x g precipitate, and immunofluorescent staining revealed diffuse cellular and perinuclear distributions. Dexamethasone pretreatment almost completely suppressed the production. We conclude that astrocytes produce galectin-9 in response to the stimulation with IL-1beta, and this may contribute to inflammatory reactions in the CNS.

Anti-Inflammatory Agents↗
PubMed2001

A novel human metalloprotease synthesized in the liver and secreted into the blood: possibly, the von Willebrand factor-cleaving protease?

We identified a novel metalloprotease, which could be responsible for cleaving the Tyr842-Met843 peptide bond of von Willebrand factor (vWF). This metalloprotease was purified from Cohn Fraction-I precipitate of human pooled plasma by the combination of gel filtration, DEAE chromatography, and preparative polyacrylamide gel electrophoresis in the presence of SDS. The NH2-terminal amino acid sequence of the isolated protein was: AAGGILHLELLVAVGPDVFQAHQEDTRRY. Based on this sequence, we searched human genomic and EST databases, and identified compatible nucleotide sequences. These results suggested that this protein is a novel metalloprotease, a member of the family of a disintegrin and metalloprotease with thrombospondin type-1 motifs (ADAMTS), and its genomic DNA was mapped to human chromosome 9q34. Multiple human tissue northern blotting analysis indicated that the mRNA encoding this protease spanned approximately 5 kilobases and was uniquely expressed in the liver. Furthermore, we determined the cDNA sequence encoding this protease, and found that this protease was comprised of a signal peptide, a proregion followed by the putative furin cleavage site, a reprolysin-type zinc-metalloprotease domain, a disintegrin-like domain, a thrombospondin type-1 (TSP1) motif, a cysteine-rich region, a spacer domain, and COOH-terminal TSP1 motif repeats.

ADAM Proteins↗
PubMed2001

Cell biology of vascular endothelial cells.

The number of molecules identified as being involved in the development of the vascular system has been increasing recently. Among those are secretory molecules and their receptors that collaborate in concert to regulate the process. Of note, however, is that we know little about the response of normal endothelial cells to different stimuli. In this study, we established a method of producing a normal endothelial population from embryonic stem cells. This new culture system was used to analyze the behavior of endothelial cells to various angiogenic stimuli. Our study demonstrated clearly that this culture system is extremely useful in revealing the behavior of developing endothelial cells. Implications derived from our observations are discussed.

Animals↗
PubMed2001

Apoptotic response of eosinophils in chronic eosinophilic pneumonia.

To clarify the pathogenesis of chronic eosinophilic pneumonia (CEP), the apoptosis of eosinophils from bronchoalveolar lavage (BAL-Eos) was compared with that of eosinophils from peripheral blood (PB-Eos) in six cases of CEP. The survival rate of eosinophils and the percentage of apoptotic cells of both types of eosinophils were examined, and the effects of interleukin 5 (IL-5) were evaluated. The role of Fas expression in apoptosis of these eosinophils was also studied. The survival rate of BAL-Eos on the third day of culture was significantly higher than that of PB-Eos (p < 0.01). This was associated with a lower proportion of apoptotic cells in BAL-Eos than in PB-Eos; the percentages of apoptotic cells in PB-Eos and BAL-Eos after 24 h of incubation were 21.7 +/- 3.4% and 10.6 +/- 1.7% respectively. IL-5 suppressed apoptosis and increased the survival rate of both PB-Eos and BAL-Eos. It was found that the apoptotic character of BAL-Eos differed from that of PB-Eos in at least three ways. Firstly, the positive rate of Fas expression on PB-Eos was increased after 24 h of incubation, whereas that on BAL-Eos did not change. Secondly, the expression of Fas on PB-Eos was suppressed by IL-5 (18.5 +/- 4.2% - 8.3 +/- 3.2%, p < 0.05), whereas IL-5 failed to suppress Fas expression on BAL-Eos (3.3 +/- 1.6% - 3.6 +/- 1.0%). Lastly, binding of antibody to Fas antigen induced apoptosis of PB-Eos, but not of BAL-Eos. These data suggested that Fas seemed to be involved in the apoptosis of PB-Eos, whereas BAL-Eos were Fas-resistant in chronic eosinophilic pneumonia. In conclusion, apoptosis of eosinophils might be suppressed by proinflammatory cytokines such as IL-5 leading to their accumulation in the lung. Chronic stimulation of eosinophils in the alveolar space with IL-5 may play a crucial role chronic eosinophilic disorders.

Adult↗
PubMed2000

Flk1-positive cells derived from embryonic stem cells serve as vascular progenitors.

Interaction between endothelial cells and mural cells (pericytes and vascular smooth muscle) is essential for vascular development and maintenance. Endothelial cells arise from Flk1-expressing (Flk1+) mesoderm cells, whereas mural cells are believed to derive from mesoderm, neural crest or epicardial cells and migrate to form the vessel wall. Difficulty in preparing pure populations of these lineages has hampered dissection of the mechanisms underlying vascular formation. Here we show that Flk1+ cells derived from embryonic stem cells can differentiate into both endothelial and mural cells and can reproduce the vascular organization process. Vascular endothelial growth factor promotes endothelial cell differentiation, whereas mural cells are induced by platelet-derived growth factor-BB. Vascular cells derived from Flk1+ cells can organize into vessel-like structures consisting of endothelial tubes supported by mural cells in three-dimensional culture. Injection of Flk1+ cells into chick embryos showed that they can incorporate as endothelial and mural cells and contribute to the developing vasculature in vivo. Our findings indicate that Flk1+ cells can act as 'vascular progenitor cells' to form mature vessels and thus offer potential for tissue engineering of the vascular system.

Animals↗
PubMed2000

Human galectin-3 is a novel chemoattractant for monocytes and macrophages.

Galectin-3 is a beta-galactoside-binding protein implicated in diverse biological processes. We found that galectin-3 induced human monocyte migration in vitro in a dose-dependent manner, and it was chemotactic at high concentrations (1.0 microM) but chemokinetic at low concentrations (10-100 nM). Galectin-3-induced monocyte migration was inhibited by its specific mAb and was blocked by lactose and a C-terminal domain fragment of the protein, indicating that both the N-terminal and C-terminal domains of galectin-3 are involved in this activity. Pertussis toxin (PTX) almost completely blocked monocyte migration induced by high concentrations of galectin-3. Galectin-3 caused a Ca2+ influx in monocytes at high, but not low, concentrations, and both lactose and PTX inhibited this response. There was no cross-desensitization between galectin-3 and any of the monocyte-reactive chemokines examined, including monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, and stromal cell-derived factor-1alpha. Cultured human macrophages and alveolar macrophages also migrated toward galectin-3, but not monocyte chemotactic protein-1. Finally, galectin-3 was found to cause monocyte accumulation in vivo in mouse air pouches. These results indicate that galectin-3 is a novel chemoattractant for monocytes and macrophages and suggest that the effect is mediated at least in part through a PTX-sensitive (G protein-coupled) pathway.

Animals↗
PubMed2000

Requirement of divalent galactoside-binding activity of ecalectin/galectin-9 for eosinophil chemoattraction.

We have previously isolated and cloned a novel eosinophil chemoattractant (ECA) from a human T-cell-derived expression library. This ECA, termed ecalectin, is a variant of human galectin-9, a member of a beta-galactoside binding animal lectin family, which contains two conserved carbohydrate recognition domains (CRDs). In the present study, we addressed whether carbohydrate binding activity is required for the ECA activity of ecalectin and whether both CRDs are essential for this activity. Recombinant full-length wild-type ecalectin (ecalectin-WT) and N-terminal and C-terminal CRD (ecalectin-NT and -CT, respectively) were generated. All of these recombinant proteins exhibited affinity for lactose, a property shared by galectins, but ecalectin-WT exhibited substantially higher hemagglutination activities than ecalectin-NT and -CT. Furthermore, ecalectin-WT showed over 100-fold higher ECA activity than ecalectin-NT and -CT; combination of recombinant domain fragments did not reconstitute the ECA and hemagglutination activities of the full-length protein. ECA activity of ecalectin-WT was inhibited by lactose in a dose-dependent manner. Site-directed mutation of positions Arg(65) of ecalectin-NT and Arg(239) of ecalectin-CT to an aspartic acid residue resulted in the loss of both lactose-binding and ECA activities. We conclude that divalent galactoside-binding activity is required for eosinophil chemoattraction by ecalectin.

Antigens, Differentiation↗
PubMed2000

Isolation of a lactose-binding protein with monocyte/macrophage chemotactic activity. Biological and physicochemical characteristics.

BACKGROUND: We established a T cell line, STO-5, which constitutively produced monocyte/macrophage chemotactic activity via human T cell lymphoma-leukemia-virus-induced transformation of normal human T cells. METHODS: We isolated and purified a lactose-binding protein, MCF-pl5-L (MW of about 50 kD, pl of about 5) from a conditioned medium of STO-5. By using highly purified MCF-pl5-L, its biological and physicochemical properties were elucidated in comparison with C5a and MCP-1. RESULTS: MCF-pl5-L exhibited an evident dose-dependent monocyte chemotactic activity (MCA). MCF-pl5-L had no or little affinity for heparin unlike chemokines such as MCP-1. We further found that MCF-pl5-L exhibited potent chemotactic activity not only for monocytes but also for alveolar macrophages. In contrast, C5a and MCP-1 failed to show evident chemotactic activity for alveolar macrophages though they did show MCA. MCF-pl5-L failed to exhibit evident eosinophil and neutrophil chemotactic activities, indicating its chemotactic activity is selective for monocytes/macrophages. Regarding the biological functions of MCF-pl5-L other than MCA and chemotactic activity for alveolar macrophages, we found that MCF-pl5-L but not C5a and MCP-1 could prolong the life span of alveolar macrophages, probably by inhibiting apoptosis of macrophages, and stimulate the production of TNF-alpha from macrophages. CONCLUSIONS: These results suggest that MCF-pl5-L plays a role as an immune modulator for monocytes/macrophages in the site.

Carrier Proteins↗
PubMed2000

Role of carbohydrate antigens sialyl Lewis (a) (CA19-9) in bronchoalveolar lavage in patients with pulmonary fibrosis.

BACKGROUND: It has been reported that carbohydrate antigen sialyl Lewis (a) (CA19-9) levels are elevated in serum as well as in bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis. However, the biological significance of CA19-9 is unclear. OBJECTIVE: The purpose of the present study was to evaluate correlations between CA19-9 levels in BALF and several biochemical as well as clinical parameters in patients with pulmonary fibrosis. In addition, biological functions of CA19-9 were also examined. METHODS: We studied 24 patients with a diagnosis of pulmonary fibrosis: 16 with idiopathic pulmonary fibrosis (IPF) and 8 with pulmonary fibrosis associated with a collagen vascular disorder (PF-CVD). In BALF, carbohydrate antigens sialyl Lewis (a) (CA19-9), elastase: alpha(1)-proteinase inhibitor complex (E-PI), hepatocyte growth factor (HGF), LDH, IgG, IgA, albumin, and cell differentiation were measured. We also evaluated the effects of CA19-9 on neutrophil functions. RESULTS: CA19-9/albumin levels in BALF significantly correlated with HGF/albumin, elastase/albumin, LDH/albumin, total number of alveolar macrophages, and total number of neutrophils. Purified CA19-9 had a chemotactic activity for neutrophils. In addition, neutrophil chemotactic activity to C5a, fMLP, and interleukin 8 was significantly stimulated after incubation with purified CA19-9. Furthermore, CA19-9 increased the expression of CD15s on neutrophils. CONCLUSIONS: Our data demonstrated (i) CA19-9 in BALF correlated with other markers of inflammation in pulmonary fibrosis, and (ii) CA19-9 can modify neutrophil functions. These results suggest that CA19-9 may play a role in the process of lung injury in patients with pulmonary fibrosis.

Adult↗
PubMed2000

Ecalectin/galectin-9, a novel eosinophil chemoattractant: its function and production.

We have recently succeeded in purifying and cloning a novel eosinophil chemoattractant, ecalectin/galectin-9, which belong to a rapidly growing galectin family. The eosinophil chemoattractant activity of ecalectin is potent and selective for eosinophils. The cellular source of ecalectin has been thought to be antigen-stimulated T cells. Herein, we will review the significance of its divalent galactoside-binding activity in ecalectin-induced eosinophil chemoattraction and the regulation of ecalectin expression in immune cells.

Animals↗
PubMed1999

Maturation of embryonic stem cells into endothelial cells in an in vitro model of vasculogenesis.

A primitive vascular plexus is formed through coordinated regulation of differentiation, proliferation, migration, and cell-cell adhesion of endothelial cell (EC) progenitors. In this study, a culture system was devised to investigate the behavior of purified EC progenitors in vitro. Because Flk-1(+) cells derived from ES cells did not initially express other EC markers, they were sorted and used as EC progenitors. Their in vitro differentiation into ECs, via vascular endothelial-cadherin (VE-cadherin)+ platelet-endothelial cell adhesion molecule-1 (PECAM-1)+ CD34(-) to VE-cadherin+ PECAM-1(+) CD34(+) stage, occurred without exogenous factors, whereas their proliferation, particularly at low cell density, required OP9 feeder cells. On OP9 feeder layer, EC progenitors gave rise to sheet-like clusters of Flk-1(+) cells, with VE-cadherin concentrated at the cell-cell junction. The growth was suppressed by Flt-1-IgG1 chimeric protein and dependent on vascular endothelial growth factor (VEGF) but not placenta growth factor (PIGF). Further addition of VEGF resulted in cell dispersion, indicating the role of VEGF in the migration of ECs as well as their proliferation. Cell-cell adhesion of ECs in this culture system was mediated by VE-cadherin. Thus, the culture system described here is useful in dissecting the cellular events of EC progenitors that occur during vasculogenesis and in investigating the molecular mechanisms underlying these processes.

3T3 Cells↗
PubMed1999

Expression of CD80 and CD86 on peripheral blood T lymphocytes in patients with systemic lupus erythematosus.

CD80 and CD86 were detected in high amounts on circulating T cells in the peripheral blood of some patients with systemic lupus erythematosus (SLE), using flow cytometry and monoclonal antibodies. Patients with other connective tissue diseases did not have a high percentage of T cells expressing CD80 or CD86 in their peripheral blood. CD80 was expressed mainly on CD4 T cells, whereas CD86 was expressed on CD8 T cells, and these two populations were associated with particular clinical features. These two molecules were expressed on different T-cell populations and might have different roles in the generation and regulation of immune responses. Since high expression of CD86 on T cells was detected much earlier than the appearance of clinical features and a high titer of anti-DNA antibody, it may be a useful parameter for predicting the flare of SLE.

Adult↗
PubMed1999

Ecalectin as a T cell-derived eosinophil chemoattractant.

In our previous papers, we have shown that human T cells produce a unique eosinophil chemotactic factor (ECF), termed Ecalectin, with a molecular weight of about 30-50 kD during interaction with BALL-1 (a B cell line) extracts, antigen or mitogen. A 1.6-kB cDNA was isolated from a human T cell-derived expression library that encodes Ecalectin. Ecalectin is a 36-kD protein consisting of 323 amino acids based on its deduced amino acid sequence. Ecalectin was found to be a variant of human galectin-9, a member of the growing family of animal lectins exhibiting affinity for beta-galactosides. Recombinant Ecalectin, expressed in COS cells, exhibited potent ECF activity in vitro and in vivo in a dose-dependent manner but not chemotactic activity for neutrophils, lymphocytes, or monocytes. The finding that the Ecalectin transcript is present in various lymphatic tissues and that its expression increases substantially in antigen-activated peripheral blood mononuclear cells suggests that Ecalectin is an important T cell-derived regulator of eosinophil recruitment in allergic reaction sites.

Animals↗