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Biomedical subjects

Y Sasaguri

Publications and source records attributed to Y Sasaguri.

At least 19 recordsLinked to original sources
PubMed2001

Effects of histamine and interleukin-4 synthesized in arterial intima on phagocytosis by monocytes/macrophages in relation to atherosclerosis.

We investigated the localization of histidine decarboxylase (HDC), which is the rate-limiting enzyme that generates histamine from histidine, in human aorta/coronary artery. RT-PCR and immunohistochemical staining revealed that the HDC gene was expressed in monocytes/macrophages and T cells in the arterial intima but not in smooth muscle cells in either the arterial intima or the media. A luciferase promoter assay with U937 and Jurkat cells demonstrated that interleukin-4 (IL-4) inhibited the expression of the HDC gene. In contrast, among a scavenger receptor family, IL-4 as well as histamine up-regulated U937 cells to express the LOX-1 gene but not the SR-A gene, which genes encode receptors that scavenge oxidized lipids. These findings suggest that histamine synthesized in the arterial wall participates in the initiation and progression of atherosclerosis and that IL-4 can act as an important inhibitory and/or stimulatory factor in the function of monocytes/macrophages modulated by histamine in relation to the process of atherosclerosis.

Arteriosclerosis↗
PubMed2001

Induction of human matrix metalloproteinase-12 gene transcriptional activity by GM-CSF requires the AP-1 binding site in human U937 monocytic cells.

Matrix metalloproteinase-12 (MMP-12) is critical for the migration of monocytes/macrophages into inflammatory sites through the basement membranes. We previously reported that MMP-12 expression was initially induced by granulocyte macrophage colony-stimulating factor (GM-CSF) in human peripheral blood monocytes and U937 monocytic cells. To further elucidate the molecular mechanism for the regulation of MMP-12 expression by GM-CSF in monocytes, we determined the sequence requirements for the MMP-12 gene transcriptional response of U937 monocytic cells to GM-CSF by using luciferase reporter and electrophoretic mobility shift assays. A series of 5'-deletion and site-directed mutation of the human MMP-12 promoter demonstrated that an AP-1 site spanning the -81 to -75-bp region is critical for the induction of MMP-12 promoter activity by GM-CSF. The electrophoretic mobility shift assay revealed that AP-1 binding activity was increased by GM-CSF treatment and that the AP-1 complex induced by GM-CSF consisted of multiple Jun and Fos isoforms. These results indicate that MMP-12 expression in U937 monocytes was initially induced by GM-CSF through the AP-1 binding activity.

5' Untranslated Regions↗
PubMed2001

Comparison of three in vitro assay systems used for assessing cytotoxic effect of heavy metals on cultured human keratinocytes.

The cell viability assay using cultured cells is of great advantage to elucidate the biological effect of potentially toxic substances. Recently, a novel assay system, Tetracolor One cell proliferation assay (Seikagaku Co., Tokyo, Japan), has been developed. In this report, we compare the results of the Tetracolor One assay regarding the cytotoxic effect of three heavy metal salts on cultured adult keratinocytes to those of the neutral red dye uptake assay and the MTT eluted stain assay. In this study, these three methods showed almost similar results. Compared to the other two methods, however, the Tetracolor One assay, which requires only one-step procedure before spectrophotometric measurement, is easier to use, and errors in measurement, which may be produced through the multistep procedure, are much less in this assay. Therefore, we believe that the Tetracolor One assay system is useful for assessing the cytotoxic effect of heavy metals on cultured human keratinocytes.

Adult↗
PubMed2001

Modulation of cell growth by the hepatitis C virus nonstructural protein NS5A.

Hepatitis C virus nonstructural protein, NS5A, is a phosphoprotein produced from the processing of the viral polyprotein precursor. NS5A associates with several cellular proteins in mammalian cells, and the biological consequences of this interaction are currently unknown. To this end, five stable NS5A-expressing murine and human cell lines were established. Tetracycline-regulated NIH3T3 cells and rat liver epithelial cells as well as the constitutive, NS5A-expressing, human Chang liver, HeLa, and NIH3T3 cells all exhibited cell growth retardation compared with the control cells. Cell cycle analysis by flow cytometry indicated that the NS5A-expressing human epitheloid tumor cells had a reduced S phase and an increase in the G(2)/M phase, which could be explained by a p53-dependent induction of p21(Waf1/Cip1) protein and mRNA levels. NS5A interacts with Cdk1 in vivo and in vitro, and a significant portion of the p21(Waf1/Cip1) was found to be in a complex with Cdk2 in the NS5A-expressing human hepatic cell line. Cdk1 and cyclin B1 proteins were also reduced in human Chang liver cells consistent with the increase in G(2)/M phase. Our results suggest that the NS5A protein causes growth inhibition and cell cycle perturbations by targeting the Cdk1/2-cyclin complexes.

3T3 Cells↗
PubMed2001

Expression of HDL receptor, CLA-1 in human smooth-muscle cells and effect of interferon-gamma on its regulation.

High-density lipoprotein (HDL) exerts antiatherogenic effects by various mechanisms. The protective effect of HDL is thought to involve the reverse transport of cholesterol from cells in the arterial wall to the liver for disposal. We previously identified human scavenger receptor BI (hSR-BI/CLA-1) as a receptor for human HDL, but did not examine the expression of hSR-BI/CLA-1 in smooth-muscle cells. In this present study, a human aortic intima smooth-muscle cell line immortalized with SV 40 DNA was established, and the expression of hSR-BI/CLA-1 in this cell line analyzed by Western blot and RT-PCR. HSR-BI/CLA-1 mRNA and protein were detected in both this cell line and primary human aortic smooth-muscle cells. A cytokine, interferon-gamma (IFN-gamma) inhibited the hSR-BI/CLA-1 protein expression, but not mRNA expression. This observation confirmed that selective cholesterol ester uptake from HDL was inhibited by IFN-gamma. These results indicated that hSR-BI/CLA-1 may be expressed in human smooth-muscle cells, and the expression may be modulated by IFN-gamma. HSR-BI/CLA-1 on smooth-muscle cells could play an important role in atherogenesis.

Aorta, Thoracic↗
PubMed2001

Phosphatidylinositol 3-OH kinase-Akt/protein kinase B pathway mediates Gas6 induction of scavenger receptor a in immortalized human vascular smooth muscle cell line.

The growth arrest-specific gene 6 encodes a secreted protein, Gas6, which was originally identified as the ligand of a receptor, Axl, with tyrosine kinase activity. The class A scavenger receptor (SRA) mediates lipid uptake into cells, leading to the formation of foam cells, an important step in atherogenesis. Although Gas6 induces SRA expression, the underlying mechanism is not clear. In this report, we show that the Gas6-induced expression of SRA was mediated by the phosphatidylinositol 3-OH kinase (PI3-kinase)-serine/threonine kinase (Akt/protein kinase B [PKB]) pathway involving Akt phosphorylation. This pathway was activated by exposure to Gas6. Furthermore, the effect of Gas6 was abrogated by wortmannin, a specific inhibitor of PI3-kinase. We also demonstrated that the constitutively active form of Akt enhanced activity of the SRA promoter but that the dominant-negative mutant of Akt completely abolished the expression of SRA after treatment with Gas6. These results show that the PI3-kinase-Akt/PKB pathway participates in Gas6-induced SRA expression and suggests that the activation of Akt/PKB plays an important role in Gas6-induced atherosclerosis and foam cell formation in human vascular smooth muscle cells.

Androstadienes↗
PubMed2000

Switch of histamine receptor expression from H2 to H1 during differentiation of monocytes into macrophages.

It is known that histamine suppresses gene expression and synthesis of tumor necrosis factor alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human peripheral blood mononuclear monocytes (HPM) or alveolar macrophages via histamine H2 receptors. We investigated the effect of histamine and differentiation in macrophages on the expression and secretion of TNF-alpha, TNF-alpha-converting enzyme (TACE), and histamine H1 and H2 receptors by use of a leukemia cell line, U937, and HPM. Differentiation of U937 and HPM cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) enhanced the H1 receptor expression and rather suppressed the H2 receptor, resulting in up-regulation of the histamine-induced expression and secretion of TNF-alpha, modulated via TACE. Therefore, histamine failed to inhibit up-regulated expression of TNF-alpha induced by LPS in macrophages. The switch from H2 to H1 receptors during differentiation in the monocyte/macrophage lineage could participate in the pathogenic processes of atherosclerosis and inflammatory reactions in the arterial wall.

ADAM Proteins↗
PubMed2000

Matrix metalloproteinases in patients with osteoarthritis of the hip.

In 78 patients undergoing a total hip replacement we examined the production of matrix metalloproteinases (MMP) by the fibroblasts from the connective tissue of the acetabulum; we then correlated these findings with clinical and radiological characteristics of the same patients. In 53 patients only MMP-2 was produced; in 15 cases MMP-1, -2 and -3 were present; and in 10 cases not only MMP-1, -2, -3 but also MMP-9. Significant differences among the clinical and radiological parameters were found in the 3 subsets. A positive correlation between the production of MMP-9 and a rapid destruction of the hip joint was found.

Adolescent↗
PubMed2000

Suppression of adjuvant arthritis of rats by a novel matrix metalloproteinase-inhibitor.

BAY 12-9566 (4-[4-(chlorophenyl)phenyl]-4-oxo-2S-(phenylthiomethyl) butanoic acid) is a newly developed, synthetic matrix metalloproteinase (MMP) inhibitor (MMPI) that selectively inhibits MMP-2, MMP-3 and MMP-9 isozymes. We study the effect of BAY 12-9566 on inflammation and cartilage destruction in adjuvant-induced arthritis (AA) in rats. Rats were injected with adjuvant and treated for 21 days with vehicle, Indomethacin or BAY 12-9566. AA was assessed: by measuring arthritic index, paw volume, urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr); by examining joint inflammation; and by microscopic morphometry of articular cartilages. Oral treatment of rats for 22 days with 50 mg kg(-1) body weight/d BAY 12-9566 showed decreased AA as determined by improvement in body weight gain (P<0.01), arthritic index (P<0.05) and swelling of paws contralateral to the adjuvant injection site (P<0.05). Neutrophil infiltration and collagen degradation were also significantly lower (P<0.01) in this treatment group. Cartilage destruction was successfully suppressed (P<0.01) in rats treated with either 50 mg kg(-1) body weight/d BAY 12-9566 or 1 mg kg(-1) body weight/d Indomethacin. These results indicate that BAY 12-9566 successfully suppressed inflammation and cartilage destruction in rats with AA. Moreover, these results also suggested that MMP-2, MMP-3 and MMP-9 are involved in arthritic diseases such as rheumatoid arthritis.

Amino Acids↗
PubMed2000

Close kinship of human 20alpha-hydroxysteroid dehydrogenase gene with three aldo-keto reductase genes.

BACKGROUND: 20alpha-Hydroxysteroid dehydrogenase (HSD) is a member of the aldo-keto reductase (AKR) superfamily and catalyses the reaction of progesterone to the inactive form 20alpha-hydroxyprogesterone. Progesterone plays an important role in the maintenance of pregnancy, and, in rodents, plasma progesterone levels decrease abruptly just before parturition. The induction of 20alpha-HSD is thought to be responsible for the decrease in plasma progesterone at term. High homology between human 20alpha-HSD [AKR 1C1] cDNA with other AKRs had caused difficulty in gene isolation and expression analysis. Thus, the metabolism of progesterone in the human reproductive system remained unclear. RESULTS: By hybridization with rat 20alpha-HSD [AKR 1C8] cDNA and high-stringency polymerase chain reaction (PCR) with gene-specific primers, we were able to isolate the human 20alpha-HSD, bile acid-binding protein (BABP) [AKR 1C2], prostaglandin F synthase (PGFS) [AKR 1C3], and dihydrodiol dehydrogenase (DD) 4 [AKR 1C4] genes. These genes had similar exon-intron organizations and shared a high homology. The four recombinant enzymes encoded by these genes showed distinct substrate specificity. By reverse transcription-PCR analysis, human 20alpha-HSD, BABP and PGFS mRNAs were expressed ubiquitously, while DD4 mRNA was restricted to the liver. Promoter activities of the 20alpha-HSD, BABP and PGFS genes were high, both in ovarian granulosa cells and hepatocytes. Radiation hybridization analysis revealed that all these genes were located close together in chromosome 10. CONCLUSION: The human gene encoding for the progesterone-metabolizing enzyme 20alpha-HSD in the female reproductive system was cloned, and its expression and gene localization were elucidated. BABP, PGFS and DD4 genes, which were highly homologous to the 20alpha-HSD gene, were also cloned, and their structure and function were characterized.

20-Hydroxysteroid Dehydrogenases↗
PubMed2000

Ovarian yolk sac tumor with virilization during pregnancy: immunohistochemical demonstration of Leydig cells as functioning stroma.

A case is reported of yolk sac tumor occurring in the left ovary and complicated by pregnancy. The 22-year-old patient presented at 28 weeks gestation with virilization and elevated serum levels of testosterone and alpha-fetoprotein. The tumor showed the typical features of yolk sac tumor with a mixture of islands of Leydig cells. The accumulations of Leydig cells were well demarcated from the cellular components of the yolk sac tumor and were distributed throughout the tumor, although with predominant localization at the periphery. By immunohistochemistry the Leydig cells were intensely positive for vimentin and negative for cytokeratins, allowing clear distinction from the cell components of the yolk sac tumor, which were positive for cytokeratins and negative for vimentin. Testosterone was also identified in the cytoplasm of the Leydig cells. After tumor resection the testosterone and alpha-fetoprotein levels declined simultaneously; this, together with the immunohistochemical demonstration of testosterone, indicates that the Leydig cells were responsible for the endocrine manifestations. Furthermore, antibodies against inhibin alpha-subunit and calretinin could be used to detect the Leydig cells. The present case, a combination of yolk sac tumor and Leydig cells acting as a functioning stroma and causing virilization during pregnancy, is very rare.

Adult↗
PubMed2000

Role of apoptosis in the closure of neonatal ductus arteriosus.

Apoptosis regulates the remodeling of tissue during embryonic development by eliminating unwanted cells and structures. The present study investigated smooth muscle cell (SMC) proliferation and apoptosis in the neonatal ductus arteriosus (DA) during closure. In the DA of 39 swine neonates and 5 autopsy human neonates, apoptosis was detected using in situ end-labeling and electron microscopy, and proliferation was evaluated using proliferating cell nuclear antigen. In swine, apoptosis of SMC was first observed at 24h after birth. After 48h, both apoptosis and proliferation quickly increased and became most prominent at 3 days, mainly in the intima and inner media. From 5 days, both apoptosis and proliferation quickly disappeared, and were present to a minor extent at the 2 weeks after birth. During these processes, there was no sign of inflammation or necrosis. In humans, apoptosis was found in tissue specimens obtained from 2 term neonates who died at 1 and 5 days after birth. These findings suggest that SMC contribute to the functional closure of the DA by active constriction, and soon after, they switch to proliferation and apoptosis, which may contribute to the anatomical closure of the DA.

Animals↗
PubMed1999

A product of growth arrest-specific gene 6 modulates scavenger receptor expression in human vascular smooth muscle cells.

Although Gas6 is identified as a growth factor for vascular smooth muscle cells (VSMCs), its roles in these cells have not been clearly elucidated. To examine the role of Gas6 in atherosclerosis, we examined the effects of Gas6 on scavenger receptor family expression in VSMCs. Scavenger receptor class A, one of the scavenger receptor family members, was upregulated in VSMCs by Gas6. Furthermore, the atherogenic lipoprotein, oxidized LDL, induced Gas6 production in these cells. These results indicate that Gas6 plays an important role in foam cell formation in human VSMCs.

Cell Line↗
PubMed1999

Transactivation of the human cdc2 promoter by adenovirus E1A. E1A induces the expression and assembly of a heteromeric complex consisting of the CCAAT box binding factor, CBF/NF-Y, and a 110-kDa DNA-binding protein.

Cyclin-dependent kinases (CDKs) play an important role in the eukaryotic cell cycle progression. Cdc2 (CDK1) is expressed in late G(1)/S phase and required for G(2) to M phase transition in higher eukaryotes. The oncoproteins, SV40 large T antigen and adenovirus E1A, induce a 110-kDa protein which specifically recognizes the two inverted CCAAT motifs of the cdc2 promoter in cycling cells and plays an essential role in transactivation of the human cdc2 promoter. Since these CCAAT motifs also conform to the consensus binding sites for the ubiquitous heterotrimeric transcription factor, CBF/NF-Y, the role of CBF/NF-Y in the transactivation of the cdc2 promoter was examined in this study. Our results indicate that CBF/NF-Y and the 110-kDa protein interact with the CCAAT box motif to form a heteromeric complex. However, mutagenesis of the pentanucleotide CCAAT motif or in the presence of urea greater than 2.5 M, no heteromeric complex was formed. In contrast, the 110-kDa protein could still bind the mutant CCAAT motif or with the wild type motif in the presence of 2.5 M urea. Furthermore, E1A.12S induced the gene expression of all three subunits of CBF/NF-Y. Coexpression of E1A and a dominant negative mutant NF-YA subunit significantly reduced the E1A-mediated transactivation of the cdc2 promoter in a dose-dependent manner. These results support the conclusion that E1A protein mediates optimal transactivation of the human cdc2 promoter by inducing the expression and assembly of a heteromeric complex consisting of the 110-kDa protein and the CBF/NF-Y which interacts with the two CCAAT motifs of the cdc2 promoter.

Adenovirus E1A Proteins↗
PubMed1999

Shortened microsatellite d(CA)21 sequence down-regulates promoter activity of matrix metalloproteinase 9 gene.

One characteristic elements in the promoter of the matrix metalloproteinase 9 (MMP-9) gene is the d(CA) repeat. To investigate whether this element regulates the transcription of the MMP-9 gene and its enzymatic activities, we sequenced the promoter region isolated from esophageal carcinoma cell lines. TE9 cells with low MMP-9 enzymatic activity had the number of d(CA) repeats shortened from 21 to 14 or 18. TE8, TE10 and TE11 cells with high MMP-9 activities had 21 or 23 d(CA) repeats. Luciferase assays using MMP-9 promoter containing 18, 14 or 0 d(CA) repeats showed transcriptional activities which were 50, 50 or 5%, respectively, of the level achieved with promoter containing 21 d(CA) repeats. Sequence analysis of the promoter of 223 Japanese subjects revealed that most had two alleles with 20, 21 or 22 d(CA) repeats, whereas six had one or two alleles with 14, 18 or 19 d(CA) repeats. We postulate that length alteration of the d(CA) repeat causes phenotypic differences among carcinoma cells and that microsatellite instability may contribute to the polymorphism of d(CA) repeat length.

Base Sequence↗
PubMed1999

Ileal varices associated with recurrent bleeding in a patient with liver cirrhosis.

We report a rare case of massive and recurrent bleeding from ileal varices in a patient with hepatitis C virus-positive liver cirrhosis. A 66-year old woman, who had undergone laparotomy and blood transfusion 36 years before (because of an extrauterine pregnancy) and endoscopic sclerotherapy for esophageal varices 1 year previously, was admitted to our hospital with loss of bright red blood per rectum. The bleeding was massive and recurrent, and frequent blood transfusions were required. Endoscopic studies failed to find the bleeding site. In the venous phase of selective superior mesenteric angiography, mesenteric varices in the lower part of the abdominal cavity were observed. Laparotomy was performed to control the repeated bleeding which had lasted for more than 1 month. Varices communicating with the right ovarian vein were found on the ileal wall and segmental resection of the ileum was performed. Histological examination demonstrated a massive varicose vein and several dilated veins in the submucosa. The patient's postoperative course was favorable, with no hemorrhagic events during a follow-up of more than 6 months after surgery. Ileal varices should be considered in the diagnosis of a patient who presents with lower gastrointestinal bleeding and portal hypertension.

Aged↗
PubMed1999

Distribution of cadmium and metallothionein in CdCl2-exposed rat kidney: relationship with apoptosis and regeneration.

Male Sprague-Dawley rats were injected subcutaneously with 0.6 mg cadmium/kg bodyweight per day for 6 weeks. In each week of exposure, rats were killed and the localization of cadmium and metallothionein in the kidney was studied by histochemical and immunohistochemical methods. Although cadmium was localized throughout the proximal tubules during exposure, apoptosis and subsequent regeneration were observed mainly in the straight portion of the proximal tubules after 4 weeks of exposure. The distribution of tubular injury may thus not necessarily coincide with that of cadmium. Expression of metallothionein was also detected in the cytoplasm and nuclei of the convoluted and the straight portion of the proximal tubules, but the latter became positive in accordance with apoptosis and regeneration. These results suggest a close relationship between metallothionein distribution and tubular cell regeneration.

Animals↗