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S Horiuchi

Publications and source records attributed to S Horiuchi.

At least 127 records · Page 7Linked to original sources
PubMed1998

Shedding of the soluble IL-6 receptor is triggered by Ca2+ mobilization, while basal release is predominantly the product of differential mRNA splicing in THP-1 cells.

The soluble IL-6 receptor (sIL-6R) is generated through either proteolytic shedding of the cognate receptor (PC-sIL-6R), or released as the product of differential mRNA splicing (DS-sIL-6R). Using monocytic THP-1 cells, we demonstrate that both mechanisms are independently regulated, and that each process contributes to sIL-6R production. Shedding of the IL-6R was activated by the Ca2+ ionophore, ionomycin, and inhibited by the TNF-alpha protease inhibitor (TAPI). In contrast, basal sIL-6R release was unaffected by Ca2+ depletion and largely insensitive to TAPI. Moreover, although IL-6R shedding was inactivated by serum starvation, non-stimulated production remained intact. Basal sIL-6R production via differential mRNA splicing was shown through the inhibitory action of brefeldin A and an enzyme-linked immunosorbent assay specific for DS-sIL-6R. Release of this isoform was unaffected by ionomycin or TAPI, indicating that Ca2+ mobilization activates PC-sIL-6R generation, but not DS-sIL-6R. The divergent control of these sIL-6R isoforms indicates that they may independently influence the inflammatory response.

Animals↗
PubMed1998

Goblet cell carcinoid of the appendix endoscopically diagnosed and examined with p53 immunostaining.

We report a case of a 62-year-old woman with goblet cell carcinoid of the appendix. She was admitted to our hospital in September 1994 after the discovery of liver tumors. After admission, a tumor in the right kidney and multiple tumors in the liver were found. She was diagnosed with renal cell cancer and metastasis to the liver and underwent excision of the kidney and enucleation of the largest liver tumor. Histological examination revealed that the liver tumor was a metastatic carcinoid tumor. As carcinoid tumors have frequently been found in the appendix, endoscopic examination was performed and a lesion was found in the appendix by colonoscopy. As predicted, the biopsy specimen was a carcinoid tumor, and she underwent an appendectomy. Histologically, the tumor was a goblet cell carcinoid. Goblet cell carcinoid is a rather rare neoplasm that has the histologic features of both carcinoids and adenocarcinoma. Forty-two cases of goblet cell carcinoid of the appendix have been reported thus far in Japan. However, few were diagnosed via endoscopic examination before surgical operation. We also carried out an immunohistochemical study with anti p53 antibody on the goblet cell carcinoid tumor of the appendix. Most tumor cells were strongly positive, while in three benign carcinoid tumors investigated simultaneously they were negative. These findings suggest that goblet cell carcinoid has an aggressive phenotype compared with benign carcinoid tumors.

Appendiceal Neoplasms↗
PubMed1998

Glycoxidation in aortic collagen from STZ-induced diabetic rats and its relevance to vascular damage.

Glycoxidation reactions lead to the formation of permanent, irreversible chemical modifications and cross-links in protein, such as the glycoxidation products carboxymethyllysine (CML) and pentosidine. It has been implicated that CML as well as Amadori products play a role in the formation of superoxidative products, such as H2O2 and advanced glycosylation endproducts in trapping LDL. Therefore, a possible relationship between glycoxidation and lipoperoxidation might exist because oxidized lipoprotein, which has been directly linked to atheroma formation, could be produced by the superoxidative products released from the pathway of CML formation. Using a CML-specific monoclonal antibody (6D12) and a specific antiserum against hexitol-lysine (HL), an Amadori product, we studied the relationship between glycoxidation and lipoperoxidation by determining the aortic CML contents with ELISA and the fluorescence levels of lipoperoxidation side products, malondialdehyde (MDA) and hydroxynonenal (HNE) from STZ-induced diabetic rats and age-matched control rats. The immunohistochemical and ultrastructural changes relevant to glycoxidation and lipoperoxidation were also studied. The CML content measured by ELISA in DM rats was significantly higher than that in the control rats at 28 weeks (n = 11, P < 0.01). The levels of MDA-linked and HNE-linked fluorescence in the DM rats increased in a similar way and were significantly higher than the levels in control rats at 28 weeks (n = 11, both P < 0.01 at 28 weeks). The CML contents correlated with the fluorescence levels of both MDA-linked (n = 19, r = 0.638, P < 0.01) and HNE-linked fluorescence (n = 19, r = 0.629, P < 0.01) only in the DM rats, but not in the control rats. Our immunohistochemical study thus demonstrated that CML was initially formed in the aortic media of diabetic rats in the 16th week of diabetes, localized primarily in the extracellular matrix surrounding the aortic smooth muscle cells after HL occurred early in the 2nd week of diabetes. Consequently, a significant increase in the extracellular matrix and decrease in the area of the SMCs were observed in the aortic media in the DM rats by a morphometrical study. The in vivo results of this study provided the first evidence that CML correlated with fluorescence levels of MDA and HNE, and thus suggested the existence of a close relationship between glycoxidation and lipoperoxidation in vivo. This information is thus considered to shed some new light on the etiology of atherogenesis in diabetes.

Aldehydes↗
PubMed1998

Immunohistochemical localization of different epitopes of advanced glycation end products in human atherosclerotic lesions.

To better understand the role of advanced glycation end products (AGEs) in atherogenesis, we developed specific antibodies against different immunological epitopes of AGE structures, including Nepsilon-(carboxymethyl)lysine-protein adduct (CML) and a structure(s) other than CML (nonCML), and demonstrated the immunohistochemical localization of CML- and nonCML-epitopes in atherosclerotic lesions of human aorta, which were obtained at autopsy from 20 nondiabetic patients (12 males and eight females; mean age, 60.8+/-16.7 years). Monoclonal anti-CML antibody (6D12) recognized not only AGE-modified proteins, but also CML-modified proteins. On the other hand, polyclonal anti-nonCML antibody reacted to AGE-modified proteins, but not to CML-modified proteins. Both antibodies were unreactive to the early-stage products of glycation, including fructose-modified butyloxycarbonyl-lysine and fructose-epsilon-aminocaproic acid. Atherosclerotic lesions included diffuse intimal thickening (DIT), fatty streaks (FS), atherosclerotic plaques (AP) and complicated lesions. An immunohistochemical analysis showed both CML- and nonCML-epitopes to be found along the collagen fibers in DIT in subjects more than 40 years old, but not in subjects less than 40 years old. CML-epitopes accumulated mainly in the cytoplasm of macrophage/foam cells, while nonCML-epitopes accumulated exclusively in the extracellular spaces in FS. APs showed the CML-epitope stored macrophage/foam cells, and the accumulation of both CML- and nonCML-epitopes in the lipid-rich fibrous area. An immunohistochemical analysis with a monoclonal antibody against oxidized low density lipoprotein (FOH1a/DLH3) showed the presence of this antigen within the cytoplasm of the macrophage/foam cells in atherosclerotic lesions, which were also positive for the CML-epitopes. These findings thus suggest that the heterogeneous localization of AGEs in atherosclerotic lesions depends on their different epitopes, and that a close link, therefore, exists between the peroxidation of LDL and the formation of AGEs in atherosclerotic lesions.

Adult↗
PubMed1998

Distribution of cathepsin E in the larval and adult organs of the bullfrog with special reference to the mature form in the larval fore-gut.

The distibution of cathepsin E in several organs of the bullfrog, Rana catesbeiana, was analyzed at pre- and post-metamorphic stages by the acid proteinase assay, by visualization of enzyme activity on polyacrlamide fore-gut gels after electrophoresis and by immunoblotting with anti-cathepsin E serum. Cathepsin E was mainly distributed in the foregut at the larval stage and in the stomach, duodenum, large intestine and gall bladder at the post-metamorphic stage. In the larval fore-gut, a higher amount of the mature form of cathepsin E was observed in addition to the proform, but in other organs, including the stomach at the post-metamorphic stage, the mature form was barely detected. Developmental changes in the amount of cathepsin E were found in the digestive tract and the gall bladder by quantitative immunoblotting analysis. Finally, the larval fore-gut was stained immunohistochemically with anti-cathepsin E serum and the surface epithelium gave a strong immunoreactive signal.

Animals↗
PubMed1998

High-level production of alternatively spliced soluble interleukin-6 receptor in serum of patients with adult T-cell leukaemia/HTLV-I-associated myelopathy.

We have previously shown, using human T-cell lymphocytotrophic virus-I (HTLV-I)-infected cell lines, that soluble interleukin-6 receptor (sIL-6R) is generated through an alternative splicing mechanism. In this study, we examined human sera for the presence of alternatively spliced soluble IL-6R (AS-sIL-6R). We produced a monoclonal antibody (mAb) recognizing the unique sequence of AS-sIL-6R peptide, generated by an altered reading frame. We also made recombinant AS-sIL-6R protein in Spodoptera frugiperda-9 (Sf-9) cells carrying baculovirus, which encoded altered sIL-6R or conventional IL-6R cDNA. mAbs specifically recognized AS-sIL-6R, but not conventional IL-6R, as demonstrated by Western blot analyses, fluorescence-activated cell sorter, immunofluorescence analyses and enzyme-linked immunosorbent assay (ELISA). We adapted an ELISA system and used it for detection of altered sIL-6R in sera from 23 healthy persons, 12 patients with adult T-cell leukaemia (ATL) and 13 patients with HTLV-I-associated myelopathy (HAM). Serum levels of AS-sIL-6R were 6.4 or 6.1 times greater in ATL (28.7+/-20.4 ng/ml, P<0.0001) and in HAM patients (27.5+/-12.1 ng/ml, P<0.0001) than in healthy individuals (4.5+/-2.1 ng/ml). High levels of AS-sIL-6R were also observed in plasma from rheumatoid arthritis patients and in persons with elevated levels of alanine aminotransferase (ALT), antinuclear antibody (ANA), or alpha-fetoprotein (AFP). However, in human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) or hepatitis C virus (HCV)-infected individuals, AS-sIL-6R levels were not elevated. In this study, we confirmed that AS-sIL-6R is indeed present in human sera. These observations suggest that alternative splicing of IL-6R mRNA is of consequence in ATL, HAM and in some autoimmune diseases. The HTLV-I-infected T cells appeared to play an important role in AS-sIL-6R production.

Adult↗
PubMed1998

Advanced glycosylation end products in adrenal lipofuscin.

The present study examined the presence of advanced glycosylation end products (AGEs) in lipofuscin present in the brain and adrenal gland of aging rats by immunohistochemistry using antibodies raised against AGEs. Lipofuscin identified as yellow to brown granules emitting bright yellow to orange autofluorescence with ultraviolet light were detected in cortical neurons, cerebellar Purkinje cells, and adrenal cells in the inner part of the zona reticularis. However, none of the antibodies visualized lipofuscin in these areas. The outer part of the zona reticularis contained yellow granules emitting a faint orange autofluorescence. These granules were immunostained by an antibody that reacted with AGEs structures unrelated to the carboxymethyllysine moiety. Newly formed adrenal cortical cells are thought to migrate from the outer layer to the inner layer of the zona reticularis. Therefore, our results suggest that glycosylation-related processes are involved in lipofuscinogenesis, at least in its early stage, in the adrenal zona reticularis.

Adrenal Cortex↗
PubMed1998

Glycolaldehyde-modified low density lipoprotein leads macrophages to foam cells via the macrophage scavenger receptor.

It was shown that proteins modified with advanced glycation end products (AGE) are effectively endocytosed by macrophages or macrophage-derived cells in vitro, and immunohistochemical studies involving anti-AGE antibodies demonstrated the accumulation of AGE-modified proteins (AGE-proteins) in macrophage-derived foam cells in human atherosclerotic lesions in situ, suggesting the involvement of AGE-modified LDL in the atherogenic process in vivo. To examine this suggestion, LDL was modified with glycolaldehyde, a highly reactive intermediate of the Maillard reaction. Physicochemically, glycolaldehyde-modified LDL (GA-LDL) was characterized by increases in negative charge, fluorescence intensity, and reactivity to anti-AGE antibodies, properties highly similar to those of AGE-proteins. The cellular interaction of GA-LDL with mouse peritoneal macrophages showed that GA-LDL was specifically recognized and endocytosed, followed by lysosomal degradation. The endocytic uptake of GA-LDL by these cells was competitively inhibited by acetylated LDL (acetyl-LDL), and the endocytic degradation of acetyl-LDL was also competed for by GA-LDL. Furthermore, incubation of GA-LDL with these macrophages and Chinese hamster ovary cells overexpressing the macrophage scavenger receptor (MSR), but not with peritoneal macrophages from MSR-knockout mice, led to the intracellular accumulation of cholesteryl esters (CE). These results raised the possibility that AGE-modified LDL, if available in situ, is taken up by macrophages mainly via MSR and then contributes to foam cell formation in early atherosclerotic lesions.

Acetaldehyde↗
PubMed1998

Elevated serum levels of the soluble form of gp130, the IL-6 signal transducer, in HTLV-1 infection and no involvement of alternative splicing for its generation.

By using an ELISA, increased levels of the soluble form (sgp130) of gp130, the IL-6 signal transducer, were detected in the sera of various HTLV-1-associated conditions (HC, ATL, HAM) as compared to normal healthy individuals. Sgp130 levels seemed to be correlated with disease severity. The 94 KD of sgp130 was specifically precipitated in the sera of HTLV-1-infected patients as revealed by Western blot analysis. A reverse transcriptase (RT)-polymerase chain reaction (PCR) method was used to detect the message for transmembrane (TM) lacking gp130 in mRNA isolated from peripheral blood mononuclear cells (PBMCs) of patients infected with or without HTLV-1 and those of various hematopoietic cell lines. Two PCR products, 648 and 507 bp were observed in the PBMCs from HTLV-1-infected patients. But the 507 by PCR product was not detected in the PBMCs from normal healthy individuals and HTLV-1-positive cell lines although the 648 bp product was equally expressed. A nucleotide sequence analysis of the 507 bp fragment showed deletion of the 141 bp at the region spanning from nucleotide 1702 (G) to 1842 (T) of the 648 bp product that matched completely with a conventional gp130 molecule. This deleted region was located upstream of the transmembrane (TM) domain, but not within the TM region itself. However, no frame shift was observed. These results indicate that the generation of sgp130 may not be due to an alternative splicing mechanism.

Alternative Splicing↗
PubMed1998

Localization of identified advanced glycation end-product structures, N epsilon(carboxymethyl)lysine and pentosidine, in age-related inclusions in human brains.

The recent identification of age-related accumulation of advanced glycation end-products (AGE) of the Maillard reaction in neurons and vessels of the human brain suggests the involvement of AGE in the aging process. A variety of inclusions such as lipofuscin granules, corpora amylacea, Hirano bodies, granulovacuolar degenerations and ubiquitin-positive granular structures are found in the aged human brain. These age-related inclusions contain insoluble and non-degradable proteins. Advanced glycation end-product-modified proteins are also known to be insoluble and protease resistant. The similarity between proteins in such inclusions and AGE-modified proteins suggests the presence of AGE in inclusions. To investigate this possibility, the presence of two known AGE structures, N epsilon(carboxymethyl)lysine (CML) and pentosidine, was examined in age-related inclusions. Immunohistochemical examination of the medial temporal area of brain tissues obtained at autopsy from seven non-demented elderly individuals demonstrated positive reactions in lipofuscin granules and corpora amylacea but not in other inclusions for anti-CML and anti-pentosidine antibodies. As CML and pentosidine are glycoxidation products among AGE, the results suggest that glycation and/or oxidation may be involved in the formation of lipofuscin granules and corpora amylacea.

Aged↗
PubMed1998

Immunohistochemical localisation of advanced glycation end products in pulmonary fibrosis.

AIM: To investigate the presence and distribution of advanced glycation end products (AGE) in pulmonary fibrosis. METHODS: Lung tissue samples obtained from seven necropsy cases with idiopathic pulmonary fibrosis and seven with normal pulmonary parenchyma were examined immunohistochemically with a monoclonal antibody specific for AGE: 6D12. We also tested three cases with diffuse alveolar damage. RESULTS: All the specimens from cases with pulmonary fibrosis and diffuse alveolar damage showed strong AGE expression on macrophages. Lung specimens from normal parenchyma showed positive AGE immunoreactivity on macrophages from only two of seven cases. CONCLUSIONS: These findings suggest that AGE modified proteins accumulate in alveolar macrophages in patients with diffuse alveolar damage and idiopathic pulmonary fibrosis.

Aged↗
PubMed1998

Accumulation of Nsigma-(carboxy-methyl)lysine and changes in glomerular extracellular matrix components in Otsuka Long-Evans Tokushima fatty rat: a model of spontaneous NIDDM.

Increases in extracellular matrix (ECM) and changes in its components have been documented in the glomeruli of diabetic nephropathy. Advanced glycation end products formed by glycoxidation have been shown to induce the synthesis of ECM components and transforming growth factor beta (TGF-beta), suggesting that advanced glycation end products may be involved in the etiology of imbalance of ECM components in diabetic glomerulosclerosis. The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an inbred strain that spontaneously develops non-insulin-dependent diabetes mellitus which progresses to diabetic glomerulosclerosis. Nepsilon-(carboxymethyl)lysine (CML) is known to be formed by glycoxidation. To clarify the involvement of glycoxidation in diabetic nephropathy, we examined the localization of CML, ECM components, and TGF-beta1 in the glomeruli of OLETF rats. The amounts of alpha3(IV) collagen, type VI collagen, and fibronectin were significantly increased in the glomeruli of OLETF rats, whereas the heparan sulfate proteoglycan levels were decreased. After 6 months of age, CML levels were significantly increased in the mesangial area of the glomeruli in these animals. The overexpression of TGF-beta1 preceded the increase in glomerular ECM components. The present study demonstrated that the accumulation of CML precedes the changes of glomerular ECM components in the glomeruli during the course of diabetic nephropathy, suggesting that glycoxidation may be one of the major causes of diabetic glomerulosclerosis.

Animals↗
PubMed1998

Expression of ACAT-1 protein in human atherosclerotic lesions and cultured human monocytes-macrophages.

The acyl coenzyme A:cholesterol acyltransferase (ACAT) gene was first cloned in 1993 (Chang et al, J Biol Chem. 1993;268:20747-20755; designated ACAT-1). Using affinity-purified antibodies raised against the N-terminal portion of human ACAT-1 protein, we performed immunohistochemical localization studies and showed that the ACAT-1 protein was highly expressed in atherosclerotic lesions of the human aorta. We also performed cell-specific localization studies using double immunostaining and showed that ACAT-1 was predominantly expressed in macrophages but not in smooth muscle cells. We then used a cell culture system in vitro to monitor the ACAT-1 expression in differentiating monocytes-macrophages. The ACAT-1 protein content increased by up to 10-fold when monocytes spontaneously differentiated into macrophages. This increase occurred within the first 2 days of culturing the monocytes and reached a plateau level within 4 days of culturing, indicating that the increase in ACAT-1 protein content is an early event during the monocyte differentiation process. The ACAT-1 protein expressed in the differentiating monocytes-macrophages was shown to be active by enzyme assay in vitro. The high levels of ACAT-1 present in macrophages maintained in culture can explain the high ACAT-1 contents found in atherosclerotic lesions. Our results thus support the idea that ACAT-1 plays an important role in differentiating monocytes and in forming macrophage foam cells during the development of human atherosclerosis.

Adult↗
PubMed1998

Changes in sleep patterns of young women from late pregnancy to postpartum: relationships to their infants' movements.

We studied changes in the sleep patterns of ten young women from late pregnancy (36 weeks) to the sixth postpartum week, focusing on the relationship between the women's sleep patterns and their infants' movements. The mothers' polysomnograms and their infants' ankle actigrams were simultaneously recorded using a Medilog 9000 at home in three sessions, during the first, third, and sixth postpartum weeks. The mother-infant pairs slept in close proximity. Two subjects had difficulty with their infants and were dealt with as a separate group. Analysis for the eight subjects who adapted well to the postpartum period showed that wake time after sleep onset increased significantly during the postpartum period compared with late pregnancy given responsibility for feeding. Stage 3 + 4 and Stage REM did not change across the four sessions (pregnancy, first, third, and sixth postpartum weeks), but Stage 2 decreased significantly from pregnancy to postpartum. There was a high synchronization between infants' movements and mothers' wakefulness. Eight mothers did not complain of sleep disturbance, while the two mothers who had difficulty with their infants did. We suggest that mothers who tolerate well sleep interruption arising from feeding and maintain their Stages 3 + 4 and REM should not be considered as suffering from sleep disturbance. Mothers who have difficulty with their infants and complain of sleep disturbance should be considered as suffering from sleep disturbance.

Adult↗
PubMed1998

Cytotoxic effect of oxidized low density lipoprotein on macrophages.

Macrophage or macrophage-derived foam cell death is one of the characteristic events in the development of cell-poor lipid-rich cores of the advanced atherosclerotic plaques. Although the in vivo mechanism for the death of macrophages is unclear, one possible candidate for the agent which induces macrophage cell death is oxidized low density lipoprotein (Ox-LDL). To investigate the mechanism of Ox-LDL-induced macrophage cell death, we have recently employed macrophage cell genetics and isolated mutant cells resistant to the cytotoxic effect of Ox-LDL from mutagenized populations of murine macrophage-derived J774 cells (Hakamata, H., Miyazaki, A., Sakai, M., Matsuda, H., Suzuki, H., Kodama, T., and Horiuchi, S. (1998) J. Lipid Res. 39, 482-494). The results obtained showed that one mutant form, JO21b cells, was characterized by reduced expression of type I and type II class A macrophage scavenger receptors (MSR-AI/AII) with a concomitant decrease in the uptake of Ox-LDL. Moreover, peritoneal macrophages obtained from MSR-AI/AII-knockout mice showed a higher resistance to the cytotoxic effect of Ox-LDL compared to those of their wild-type littermates. From these results, we have concluded that Ox-LDL cytotoxicity to macrophages is enhanced by effective endocytic uptake of Ox-LDL through MSR-AI/AII. These findings imply a possibility that formation of the cell-poor lipid-rich core is also enhanced by MSR-AI/AII-mediated uptake of Ox-LDL and subsequent macrophage cell death in atherosclerotic lesions.

Animals↗
PubMed1998

Determination of glycated albumin by enzyme-linked boronate immunoassay (ELBIA).

A new affinity method for quantification of glycated albumin by an enzyme-linked boronate-immunoassay (ELBIA) has been established, based on the interaction between boronic acids and the cis-diols of glycated human serum albumin (HSA) trapped by anti-HSA antibody. To evaluate the ELBIA, we first examined the accuracy of the conventional boronate affinity chromatographic (BAC) method. In the BAC method, 8.1-18.9% of nonglycated albumin calibrator nonspecifically bound to the boronate affinity column, values that were regarded as the column blank. In the modified BAC method, therefore, we substracted the column blank value from the measured glycated albumin value to obtain the true value. Because glycated albumin values measured by ELBIA were exactly the same as reported by the modified BAC method, we suggest that the ELBIA results reflect the real status of albumin glycation. We have also developed a fully automated ELBIA system, allowing multiple, rapid, and precise measurements of glycated albumin.

Boronic Acids↗
PubMed1998

Isolation of macrophage-like cell mutants resistant to the cytotoxic effect of oxidized low density lipoprotein.

A high concentration of oxidized low density lipoprotein (Ox-LDL) showed a cytotoxic effect on mouse macrophage-derived J774 cells. Mutant cells were selected from these cells that were resistant to the cytotoxic effect of Ox-LDL. One mutant form, named JO21b cells, was characterized in the present study. In spite of a marked resistance to the cytotoxic effect of Ox-LDL, JO21b cells were apparently as sensitive as the parent cells not only to toxic moieties of Ox-LDL, such as 7-ketocholesterol and lysophosphatidylcholine, but also to t-butyl hydroperoxide, an artificial lipid hydroperoxide analog. However, the cellular association of 125I-labeled Ox-LDL with, and subsequent endocytic degradation by JO21b cells was reduced by 70-80% compared with J774 cells. Similarly, accumulation of cholesteryl esters in JO21b cell by Ox-LDL was also reduced by 70%. Northern blot analyses of type I and type II macrophage scavenger receptors (type I and type II MSR) demonstrated that the mRNA levels of JO21b cells were lower than those of J774 cells. Moreover, peritoneal macrophages obtained from MSR-knockout mice showed a higher resistance to the cytotoxic effect of Ox-LDL than those from their wild-type littermates. Our results suggest, therefore, that macrophage scavenger receptor-mediated endocytic uptake of oxidized low density lipoproteins (Ox-LDL) may play an enhancing role in Ox-LDL cytotoxicity to macrophages or macrophage-derived cells.

Animals↗