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H Saito

Publications and source records attributed to H Saito.

At least 109 records · Page 6Linked to original sources
PubMed2001

Syndecan-4 deficiency leads to high mortality of lipopolysaccharide-injected mice.

Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Following intraperitoneal injection of lipopolysaccharide (LPS), syndecan-4-deficient mice exhibited high mortality compared with wild-type controls. Severe endotoxin shock was observed in the deficient mice: systolic blood pressure and left ventricular fractional shortening were lower in the deficient mice than in the wild-type controls 9 h after LPS injection. Although histological examinations revealed no apparent differences between two groups, the plasma level of interleukin (IL)-1beta was higher in the deficient mice than in the wild-type controls 9 h after LPS injection. Consistent with the regulatory roles of syndecan-4, its expression in monocytes and endothelial cells of microvasculature increased in the wild-type mice after LPS administration. Although IL-1beta was produced to the same extent by macrophages from syndecan-4-deficient and wild-type mice after LPS stimulation, inhibition of its production by transforming growth factor-beta1 was impaired in the syndecan-4-deficient macrophages. These results indicate that syndecan-4 could be involved in prevention of endotoxin shock, at least partly through the inhibitory action of transforming growth factor-beta1 on IL-1beta production.

Animals↗
PubMed2001

Histone deacetylase 3 associates with and represses the transcription factor GATA-2.

The zinc finger transcription factor GATA-2 plays a critical role in the survival and proliferation of hematopoietic stem cells. This study examined the interaction of GATA-2 with histone deacetylases (HDACs) to define the involvement of HDACs in the regulation of GATA-2 function. GATA-2 directly associates with HDAC3 but not with HDAC1. Consistent with this, HDAC3 suppressed the transcriptional potential of GATA-2, whereas HDAC1 did not affect GATA-2-dependent transcription. Results further demonstrated that GATA-2 and HDAC3 colocalized in the nucleus. These results identify GATA-2 as a nuclear target for HDAC3-mediated repression. Furthermore, GATA-2 also directly associated with HDAC5 but not with other class II HDACs examined, that is, HDAC4 and HDAC6. This is the first demonstration that a tissue-specific transcription factor directly and selectively interacts with HDAC3 and HDAC5 among HDAC family members.

Animals↗
PubMed2001

Resonance energy transfer study of peptide-lipid complexes.

Resonance energy transfer involving tryptophan as a donor and anthrylvinyl-labeled phosphatidylcholine (AV-PC), 3-methoxybenzanthrone (MBA) and 8-anilino-1-naphthalene sulfonic acid (ANS) as acceptors has been examined to obtain information on the structure of peptide-lipid systems consisting of 18A or Ac-18A-NH(2) peptides and large unilamellar phosphatidylcholine vesicles. The lower and upper limits for the tryptophan distance from the bilayer midplane have been assessed in terms of the models of energy transfer in two-dimensional systems, taking into account orientational effects. Evidence for the existence of preferential orientations of Ac-18A-NH(2) with respect to the lipid-water interface has been obtained.

Algorithms↗
PubMed2001

Decrease of substance P in the parabrachial nucleus of multiple system atrophy.

In the parabrachial nucleus (PBN), which has been known to play an important regulating role for various autonomic functions, many projecting nerve fiber terminals containing substance P (SP) from the nucleus of the solitary tract (NTS) and other areas are found and effect a modulatory influence on the transmission in the PBN. Postmortem brains were obtained from four multiple system atrophy (MSA) patients with autonomic failure and four control patients without any nervous disease, and an immunohistochemical staining for SP was performed on serial 10-microm-thick sections from paraffin-embedded pons including the PBN after immersion fixation in 10% formalin. In the PBN of all MSA patients, a marked decrease in SP-like immunoreactive (SPLI) nerve fiber terminals was revealed compared with the controls. In addition, an obvious astrocytosis was found in the PBN by simultaneous histopathological evaluation, for the preservation of neurons themselves. Therefore, the projecting SP pathway to the PBN may also be primarily involved in the pathophysiological mechanism of the autonomic failure of MSA patients.

Autonomic Nervous System Diseases↗
PubMed2001

Significance of cadmium concentrations in blood and hair as an indicator of dose 15 years after the reduction of environmental exposure to cadmium.

To evaluate the significance of cadmium (Cd) concentrations in blood (B-Cd) and hair (H-Cd) as an indicator of dose, a cross-sectional study was performed on 40 residents in a Cd-polluted area, Nagasaki Prefecture, Japan, in 1996. In the study area, soil replacement of Cd-polluted rice fields ended in 1981. B-Cd and H-Cd were significantly higher in the study population than in the control subjects. B-Cd was positively correlated with urinary Cd (U-Cd) (Spearman r=0.50, P=0.06 for males and r=0.72, P=0.0001 for females), while H-Cd was weakly or moderately correlated with U-Cd. After adjustment for gender using logistic regression analysis, log(B-Cd) and log(U-Cd), but not log(H-Cd), were significantly associated with the prevalence of increased urinary beta2-microglobulin (P for trend <0.05). These findings suggest that B-Cd is a good indicator of cumulative dose many years after the reduction of environmental exposure to Cd. H-Cd may be weakly or moderately correlated with body burden.

Adult↗
PubMed2001

The receptor tyrosine phosphatase Dlar and integrins organize actin filaments in the Drosophila follicular epithelium.

BACKGROUND: Regulation of actin structures is instrumental in maintaining proper cytoarchitecture in many tissues. In the follicular epithelium of Drosophila ovaries, a system of actin filaments is coordinated across the basal surface of cells encircling the oocyte. These filaments have been postulated to regulate oocyte elongation; however, the molecular components that control this cytoskeletal array are not yet understood. RESULTS: We find that the receptor tyrosine phosphatase (RPTP) Dlar and integrins are involved in organizing basal actin filaments in follicle cells. Mutations in Dlar and the common beta-integrin subunit mys cause a failure in oocyte elongation, which is correlated with a loss of proper actin filament organization. Immunolocalization shows that early in oogenesis Dlar is polarized to membranes where filaments terminate but becomes generally distributed late in development, at which time beta-integrin and Enabled specifically associate with actin filament terminals. Rescue experiments point to the early period of polar Dlar localization as critical for its function. Furthermore, clonal analysis shows that loss of Dlar or mys influences actin filament polarity in wild-type cells that surround mutant tissues, suggesting that communication between neighboring cells regulates cytoskeletal organization. Finally, we find that two integrin alpha subunits encoded by mew and if are required for proper oocyte elongation, implying that multiple components of the ECM are instructive in coordinating actin fiber polarity. CONCLUSIONS: Dlar cooperates with integrins to coordinate actin filaments at the basal surface of the follicular epithelium. To our knowledge, this is the first direct demonstration of an RPTP's influence on the actin cytoskeleton.

Actin Cytoskeleton↗
PubMed2001

Lipid binding-induced conformational change in human apolipoprotein E. Evidence for two lipid-bound states on spherical particles.

Apolipoprotein (apo) E contains two structural domains, a 22-kDa (amino acids 1-191) N-terminal domain and a 10-kDa (amino acids 223-299) C-terminal domain. To better understand apoE-lipid interactions on lipoprotein surfaces, we determined the thermodynamic parameters for binding of apoE4 and its 22- and 10-kDa fragments to triolein-egg phosphatidylcholine emulsions using a centrifugation assay and titration calorimetry. In both large (120 nm) and small (35 nm) emulsion particles, the binding affinities decreased in the order 10-kDa fragment approximately 34-kDa intact apoE4 > 22-kDa fragment, whereas the maximal binding capacity of intact apoE4 was much larger than those of the 22- and 10-kDa fragments. These results suggest that at maximal binding, the binding behavior of intact apoE4 is different from that of each fragment and that the N-terminal domain of intact apoE4 does not contact lipid. Isothermal titration calorimetry measurements showed that apoE binding to emulsions was an exothermic process. Binding to large particles is enthalpically driven, and binding to small particles is entropically driven. At a low surface concentration of protein, the binding enthalpy of intact apoE4 (-69 kcal/mol) was approximately equal to the sum of the enthalpies for the 22- and 10-kDa fragments, indicating that both the 22- and 10-kDa fragments interact with lipids. In a saturated condition, however, the binding enthalpy of intact apoE4 (-39 kcal/mol) was less exothermic and rather similar to that of each fragment, supporting the hypothesis that only the C-terminal domain of intact apoE4 binds to lipid. We conclude that the N-terminal four-helix bundle can adopt either open or closed conformations, depending upon the surface concentration of emulsion-bound apoE.

Apolipoproteins E↗
PubMed2001

Gene expression screening of human mast cells and eosinophils using high-density oligonucleotide probe arrays: abundant expression of major basic protein in mast cells.

Mast cells (MCs) and eosinophils are thought to play important roles in evoking allergic inflammation. Cell-type--specific gene expression was screened among 12,000 genes in human MCs and eosinophils with the use of high-density oligonucleotide probe arrays. In comparison with other leukocytes, MCs expressed 140 cell-type--specific transcripts, whereas eosinophils expressed only 34. Among the transcripts for expected MC-specific proteins such as tryptase, major basic protein (MBP), which had been thought to be eosinophil specific, was ranked fourth in terms of amounts of increased MC-specific messenger RNA. Mature eosinophils were almost lacking this transcript. MCs obtained from 4 different sources (ie, lung, skin, adult peripheral blood progenitor--derived and cord blood progenitor--derived MCs, and eosinophils) were found to have high protein levels of MBP in their granules with the use of flow cytometric and confocal laser scanning microscopic analyses. The present finding that MCs can produce abundant MBP is crucial because many reports regarding allergic pathogenesis have been based on earlier findings that MBP was almost unique to eosinophils and not produced by MCs. (Blood. 2001;98:1127-1134)

Adult↗
PubMed2001

Synthetic utility of stannyl enolates as radical alkylating agents.

[reaction: see text] The radical-initiated beta-ketoalkylation of haloalkanes with tributylstannyl enolates is described. Stannyl enolates derived from aromatic ketones are reactive toward the homolytic beta-ketoalkylation of simple haloalkanes as well as those activated by an electron-withdrawing group. The reactivity of stannyl enolates as radical alkylating agents can be utilized for an efficient three-component coupling reaction among stannyl enolates, haloalkanes, and electron-deficient alkenes.

Journal Article↗
PubMed2001

Multi-faceted analyses of a highly metastatic human lung cancer cell line NCI-H460-LNM35 suggest mimicry of inflammatory cells in metastasis.

This study established and characterized low-metastatic revertant and parental clones of a highly metastatic human lung cancer cell line, NCI-H460-LNM35 (hereafter referred to as LNM35). Expression-profiling analysis revealed that up-regulation of various proinflammatory cytokines and angiogenic chemotactic chemokines was present in LNM35. Further, while COX-2 itself is known to be inducible in inflammation, COX-2 expression levels correlated well with the capabilities of these clones for not only in vitro motility and invasion but also in vivo metastasis, and COX-2 inhibitors were shown for the first time to reduce lung cancer metastasis in vivo. These findings suggest that lung cancer cells may mimic inflammatory cells in the process of metastasis.

Animals↗
PubMed2001

Lano, a novel LAP protein directly connected to MAGUK proteins in epithelial cells.

Protein networks asymetrically distributed to basolateral and apical epithelial membranes maintain cell polarity and homeostasis of epithelial tissues. Genetic studies in non-vertebrates assigned two families of basolateral proteins, MAGUK (membrane-associated and guanylate kinase) and LAP (leucine-rich repeats and PDZ) proteins, to a common pathway crucial for the epithelial architecture and acting as a gatekeeper to malignancy. In mammals, three LAP proteins have been described, Densin-180, Erbin, and hScribble. Here, we identify a protein called Lano (LAP and no PDZ) only present in vertebrates and presenting strong identities with LAP proteins. Despite the lack of PDZ domain, Lano is located at the basolateral side of epithelial cells in a similar manner to Erbin and hScribble. Using in vitro and in vivo experiments, we demonstrate that Lano directly interacts with the PDZ domains of MAGUK proteins, including hDLG (human disc large), in epithelial cells. A second pool of Lano is complexed to Erbin. These LAP-MAGUK protein complexes coexist at the basolateral side of epithelial cells. We provide evidence for a direct interaction between LAP and MAGUK proteins, and we propose that various LAP-MAGUK networks targeted to the basolateral side of epithelial cells participate to homeostasis of epithelial tissues and tumor growth.

Amino Acid Sequence↗
PubMed2001

Granulocyte colony-stimulating factor (G-CSF)-mediated signaling regulates type IV collagenase activity in head and neck cancer cells.

Granulocyte colony-stimulating factor (G-CSF), a hematopoietic cytokine, regulates the proliferation and differentiation of granulocytic progenitor cells and functionally activated mature neutrophils. G-CSF also affects nonhematopoietic tumor cells through its binding to the specific receptor (G-CSFR) on the cells. The type IV collagenase [matrix metalloproteinase 2 (MMP-2)] is known to play a main role in the process of invasion and metastasis, but its regulation, for example, in expression or in activation, is not clearly understood. In this study, we investigated the role of G-CSF in the regulation of tumor cell invasion and the synthesis of MMP-2. G-CSFs producing the head and neck carcinoma cell line T3M-1 cells with metastatic ability and no G-CSF receptor (G-CSFR) expression were transfected with G-CSFR expression vector. In vitro treatment of G-CSFR-transfectant T3M-1 cells with recombinant G-CSF (rG-CSF) significantly augmented their invasive potential in a reconstituted basement membrane (Matrigel) system compared with that of parental cells. Moreover, MMP-2 activity of G-CSFR-transfectant T3M-1 cells was enhanced by the stimulation with rG-CSF, as assessed by gelatin zymography. These results identify G-CSF as a regulator of MMP-2 and cellular invasion.

Carcinoma, Squamous Cell↗
PubMed2001

IL-1 induced chemokine production through the association of Syk with TNF receptor-associated factor-6 in nasal fibroblast lines.

The fibroblasts stimulated by cytokines released the chemokine and recruited the infiltrating cells, including eosinophils, that play a key role in the pathogenesis of airway disease. We established the human fibroblast lines showing high Syk expression and the lines showing low Syk expression from pieces of nasal polyp. IL-1 induces the interaction of TNFR-associated factor (TRAF) 6 with IL-1R-associated kinase, which is rapidly recruited to the IL-1R after IL-1 induction, whereas TRAF2 participates in TNF-alpha-signaling. In the present study, we found that Syk played a different role in IL-1- and TNF-alpha-induced chemokine production through a signaling complex involving Syk and TRAF6. Overexpression of wild-type Syk by gene transfer enhanced RANTES production from nasal fibroblasts stimulated with IL-1. The decrease of Syk expression by the administration of Syk antisense inhibited RANTES production in response to IL-1. However, the change of Syk expression did not affect RANTES production by TNF-alpha stimulation. We concluded that Syk is required for the IL-1-induced chemokine production through the association with TRAF-6 in fibroblasts of nasal polyps.

Cell Line↗
PubMed2001

Identification of novel mast cell genes by serial analysis of gene expression in cord blood-derived mast cells.

The gene expression profile of human cord blood-derived mast cells (MCs) was investigated using serial analysis of gene expression (SAGE). A total of 22914 tags, representing 9181 unique transcripts, were sequenced. By selecting tags that were detected more frequently in MCs than in other tissues, genes characteristic of MCs were enriched. Reverse transcription-PCR and the high-density oligonucleotide array hybridization confirmed the validity of our SAGE result. About 70% of the selected genes were previously uncharacterized. Northern blot analysis showed the MC-specific expression of selected genes. This inventory will be useful to identify novel genes with important functions in MCs.

Cells, Cultured↗
PubMed2001

Age-associated differences in cardiovascular inflammatory gene induction during endotoxic stress.

Upon physiological stress, families of stress response genes are activated as natural defense mechanisms. Here, we show that induction of specific inflammatory genes is significantly dysregulated and altered in the heart of aged (24--26-month-old) versus young (4-month-old) mice experimentally challenged with a bacterial endotoxin, lipopolysaccharide (LPS, 1.5 mg/kg of body mass). Whereas the LPS-mediated induction of cardiac mRNA for tumor necrosis factor alpha or inducible nitric-oxide synthase showed no age-associated differences, the induction of interleukin-1 beta (IL-1 beta) and intracellular adhesion molecule-1 was modestly extended with aging, and the induction of IL-6 was significantly prolonged with aging. This age-associated phenomenon occurred gradually from 4 to 17 months of age and became more evident after 23 months of age. The age-associated augmentation of the cardiac IL-6 induction was also dramatic at the protein level. Immunohistochemically, the LPS-induced cardiac IL-6 was localized mainly in the microvascular walls. Aged but not young mice showed a high mortality rate during these experiments. These results demonstrate that endotoxin-mediated induction of specific inflammatory genes in cardiovascular tissues is altered with aging, which may be causally related to the increased susceptibility of aged animals to endotoxic stress.

Aging↗
PubMed2001

Cyclosporin A inhibits the extrusion pump function of p-glycoprotein in the inner ear of mice treated with vinblastine and doxorubicin.

Cyclosporin A (CsA) inhibits the membrane transport protein p-glycoprotein (p-gp) and can enhance the accumulation of vinblastine (VBL) and doxorubicin (Dx) in the inner ear of mice. In mice pretreated with 200 mg/kg of CsA, there were significantly increased VBL and Dx concentrations detected in the inner ear tissue and other organs, with a small but significant increase in the brain. Furthermore, hearing thresholds measured by auditory brainstem responses were significantly elevated 3 weeks after VBL or Dx treatment in combination with CsA. However, the altered thresholds recovered to pretreatment levels 8 weeks after treatment. Pharmacokinetic and functional alterations observed in this study suggest caution in applying these combinations in clinical practice.

ATP Binding Cassette Transporter, Subfamily B, Mem↗