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Biomedical subjects

I Iwamoto

Publications and source records attributed to I Iwamoto.

At least 73 records · Page 4Linked to original sources
PubMed1998

Phosphorylation of alphaB-crystallin in mitotic cells and identification of enzymatic activities responsible for phosphorylation.

The immunofluorescence localization of alphaB-crystallin in U373 MG human glioma cells with an antibody specific for alphaB-crystallin that had been phosphorylated at Ser-45 revealed an intense staining of cells in the mitotic phase of the cell cycle. Phosphorylated forms of alphaB-crystallin in mitotic cells were detected in all cell lines examined and in tissue sections of mouse embryos. Increases in the levels of alphaB-crystallin that had been phosphorylated at Ser-45 and Ser-19, but not at Ser-59, were detected biochemically by isoelectric focusing or SDS-polyacrylamide gel electrophoresis and a subsequent Western blot analysis of extracts of cells collected at the mitotic phase. When we estimated the phosphorylation activity specific for alphaB-crystallin in extracts of mitotic U373 MG cells, using the amino-terminal 72-amino acid peptide derived from unphosphorylated alphaB2-crystallin as the substrate, we found that the activities responsible for the phosphorylation of Ser-45 and Ser-19 were markedly enhanced but that the activity responsible for the phosphorylation of Ser-59 was suppressed. The protein kinases responsible for the phosphorylation of Ser-45 and Ser-59 in the amino-terminal 72-amino acid peptide were partially purified from extracts of cells that had been stimulated by exposure to H2O2 in the presence of calyculin A. The activities responsible for the phosphorylation of Ser-45 and Ser-59 were eluted separately from a column of Superdex 200 at fractions corresponding to about 40 and 60 kDa, respectively, while the kinase for Ser-19 was unstable. p44/42 mitogen-activated protein (MAP) kinase and MAP kinase-activated protein (MAPKAP) kinase-2 were concentrated in the Ser-45 kinase fraction and Ser-59 kinase fraction, respectively. Recombinant human p44 MAP kinase and MAPKAP kinase-2 purified from rabbit muscle selectively phosphorylated Ser-45 and -59, respectively. The Ser-45 kinase fraction and Ser-59 kinase fraction phosphorylated myelin basic protein and hsp27, respectively. These results suggest that the phosphorylations of Ser-45 and Ser-59 in alphaB-crystallin are catalyzed by p44/42 MAP kinase and MAPKAP kinase-2, respectively, in cells and that the phosphorylation of Ser-45 by p44/42 MAP kinase is enhanced while the phosphorylation of Ser-59 by MAPKAP kinase-2 is suppressed during cell division.

Animals↗
PubMed1998

Cross-linking of intercellular adhesion molecule-1 induces interleukin-8 and RANTES production through the activation of MAP kinases in human vascular endothelial cells.

We investigated whether intercellular adhesion molecule-1 (ICAM-1) transduces outside-in signals for the production of chemokines IL-8 and RANTES in endothelial cells. Cross-linking of ICAM-1 induced IL-8 and RANTES mRNA expressions and increased their protein synthesis and secretions in endothelial cells. Furthermore, ICAM-1 cross-linking activated 44- and 42-kDa mitogen-activated protein (MAP) kinases (ERK1 and ERK2) in endothelial cells, as indicated by the electrophoretic mobility shift of MAP kinases on SDS-polyacrylamide gels. Finally, the specific MEK inhibitor PD98059 inhibited ICAM-1-induced IL-8 and RANTES production in endothelial cells. Taken together, these results indicate that stimulation of ICAM-1 induces IL-8 and RANTES production through the activation of 44- and 42-kDa MAP kinases in endothelial cells, suggesting that ICAM-1-induced chemokine production in endothelial cells would further attract and activate leukocytes to induce intense inflammation.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1998

A single missense mutant of Smad3 inhibits activation of both Smad2 and Smad3, and has a dominant negative effect on TGF-beta signals.

A missense mutation of Smad2 identified in cancer cells was reconstructed on the corresponding residue of Smad3. This mutant, Smad3D407E, was not phosphorylated by the constitutively active form of type I receptor for transforming growth factor-beta (TGF-beta), and inhibited the phosphorylation of co-expressed wild-type Smad2 and Smad3. This mutant also had a dominant negative effect on the growth inhibition of HaCaT cells and on the expression of p3TP-lux reporter gene induced by TGF-beta. However, it did not alter the phosphorylation of Smad1 induced by the constitutively active form of the bone morphogenetic protein type IA receptor. These findings showed that a single missense mutation in Smad3 could specifically block TGF-beta signals by preventing activation of both Smad2 and Smad3.

Amino Acid Sequence↗
PubMed1998

Inhibitory effect of F-1322 on allergic eosinophil infiltration in airways.

The effects of F-1322 (N-[2-[4-(benzhydryloxy)piperidino]ethyl]-3-hydroxy-5-(3-pyridy lmethoxy)-2-naphthamide) on antigen-induced eosinophil infiltration and interleukin-5 production in the airways and on in vitro eosinophil migration were investigated. F-1322 (10-30 mg/kg, p.o.) inhibited antigen-induced eosinophil infiltration and interleukin-5 production in the airways of sensitized mice in a dose-dependent manner. Furthermore, F-1322 (0.1-10 microM) prevented the in vitro migration of eosinophils from guinea-pigs and humans induced by recombinant human interleukin-5, platelet-activating factor, and leukotriene B4 in a concentration-dependent manner. These results indicate that F-1322 has an inhibitory effect on allergic eosinophil infiltration of the airways by preventing both eosinophil migration and interleukin-5 production. These pharmacological profiles suggest that F-1322 will be a useful therapeutic for allergic diseases, especially asthma.

Animals↗
PubMed1998

T cell receptor clonotypes in skin lesions from patients with systemic lupus erythematosus.

Systemic lupus erythematosus is an autoimmune disease characterized by the presence of autoantibodies and by lymphocytic infiltration into lesions at several sites such as skin, kidney, and other organs. Immunohistologic studies have clarified that the majority of lymphocytes in the skin are CD4+ alphabeta T cells. In the present work, to clarify the pathologic role of T cells in the skin of systemic lupus erythematosus patients, we analyzed T cell receptor (TCR) clonotypes of T cells infiltrating into skin lesions. TCR Vbeta gene transcripts from T cells from discoid lesions of the skin and peripheral blood lymphocytes of four systemic lupus erythematosus patients were amplified by reverse transcriptase polymerase chain reaction. Southern blot analysis of polymerase chain reaction product demonstrated the heterogeneous TCR Vbeta repertoire of T cells in the skin of systemic lupus erythematosus. Single-strand conformation polymorphism analysis showed several distinct bands for smears of most TCR Vbeta genes from T cells infiltrating the skin, whereas smears with few bands were found for all TCR Vbeta genes from peripheral blood lymphocytes of the same patients. The number of bands encoding each TCR Vbeta gene from the skin was significantly higher compared with peripheral blood lymphocytes. Sequencing analysis showed a Leucine-X-Glycine amino acid motif at position 96-98 in the CDR3 region at the frequency of 23-24% in skin-accumulated T cells from two patients, whereas the frequency of this motif in peripheral T cells was only 0-3%, indicating limited T cell epitopes. In conclusion, T cells infiltrating into the skin of systemic lupus erythematosus patients might recognize restricted T cell epitopes on autoantigens and trigger the autoimmune reaction in skin lesions.

Amino Acid Sequence↗
PubMed1998

High-dose oral tolerance prevents antigen-induced eosinophil recruitment into the mouse airways.

We have previously shown that antigen-induced eosinophil recruitment into the tissue of sensitized mice is mediated by CD4+ T cells and IL-5. To determine whether the induction of oral tolerance down-regulates antigen-induced eosinophil recruitment into the tissue, we studied the effect of oral administration of a protein antigen on antigen-induced eosinophil infiltration in the trachea of sensitized mice, on antigen-induced CD4+ T cell infiltration and IL-5 production in the airways, and on the in vitro production of IL-2, IL-4, IL-5 and IFN-gamma in spleen cells of the mice. Oral administration of a protein antigen in high doses inhibited antigen-induced eosinophil infiltration in the trachea and IgE antibody production in mice in an antigen-specific manner. The oral administration of antigen also suppressed both CD4+ T cell recruitment into the trachea and IL-5 levels in the bronchoalveolar lavage fluids of the mice after antigen inhalation. In vitro antigen-induced production of IL-2, IFN-gamma, IL-4 and IL-5 was decreased in spleen cells of antigen-fed mice, indicating the induction of both Th1 and Th2 cell tolerance in vivo. On the other hand, pretreatment with anti-transforming growth factor-beta antibody at the time of immunization with antigen had no significant effect on the inhibition of antigen-induced eosinophil recruitment and IgE antibody production in antigen-fed mice. Finally, antigen-specific CD4+ T cells were not deleted in TCR transgenic mice after antigen feeding by FACS analysis. Taken together, these results indicate that high-dose oral tolerance induces not only Th1 but also Th2 cell tolerance in vivo and thereby inhibits antigen-induced eosinophil recruitment into the tissue.

Administration, Oral↗
PubMed1998

Acquired reactive perforating collagenosis with IgA nephropathy.

A 25-year-old Japanese man developed numerous discrete umbilicated papules on his face, trunk, and both forearms at the onset of IgA nephropathy. The newest lesion was a nonumbilicated skin-colored papule. On histopathologic examination, alteration of capillaries was observed in both newer and umbilicated papules. In our case, a primary cause of the reactive perforating collagenosis could be an alteration of the capillaries.

Adrenal Cortex Hormones↗
PubMed1998

Anti-glomerular basement membrane nephritis after extracorporeal shock wave lithotripsy.

Rapidly progressive glomerulonephritis was observed in a 37-year-old woman following the administration of extracorporeal shock wave lithotripsy (ESWL) for a single stone in her right kidney. The renal biopsy specimen showed diffuse cellular crescents in all glomeruli, with linear deposits of immunoglobulin G and complement component C3 along the glomerular basement membrane (GBM). Circulating anti-GBM antibodies were detected by enzyme-linked immunosorbent assay. Thus, the patient was diagnosed with anti-GBM nephritis. It is suggested that ESWL produced an alteration in the GBM leading to the production of anti-GBM antibodies.

Adult↗
PubMed1998

Blockade of CD28/B7 interaction suppresses allergic eosinophilic inflammation in mice.

To determine whether the costimulatory signal via CD28/B7 interaction is required for causing allergic inflammation, we examined the effect of administration of CTLA4-Ig, a fusion protein of the extracellular domain of CTLA4 and human IgG1-constant region, at the time of sensitization, on antigen-induced eosinophil infiltration in the trachea of sensitized mice, on IL-2, IFN-gamma, IL-4 and IL-5 production in the airways of the mice and on antigen-specific IgE synthesis in the mice. Administration of CTLA4-Ig at the time of sensitization suppressed antigen-induced eosinophil infiltration into the trachea and antigen-specific IgE production in mice. Furthermore, CTLA4-Ig administration at the time of sensitization suppressed not only IL-2 production but also IFN&hyphengamma and Th2 cytokine IL-4 and IL-5 production in the airways. Because allergic inflammation requires CD4+ T cells producing Th2-type cytokines IL-4 and IL-5, our results suggest that the costimulatory signal via CD28/B7 interaction is important for the generation and activation of Th2 cells and thereby for the development of allergic inflammation.

Abatacept↗
PubMed1998

Stimulation of the stress-induced expression of stress proteins by curcumin in cultured cells and in rat tissues in vivo.

Curcumin, a major component of turmeric, a seasoning commonly used in Indian food, and a known antioxidant, anti-inflammatory and anti-carcinogenic agent, is a potent stimulator of the stress-induced expression of Hsp27, alphaB crystallin and Hsp70. When C6 rat glioma cells were exposed to arsenite (100 microM for 1 h), CdCl2 (100 microM for 1 h) or heat (42 degrees C for 30 min) in the presence of 3-10 microM curcumin, induction of the synthesis of all three proteins was markedly stimulated, as detected by specific immunoassays, Western blot analysis and Northern blot analysis. A gel mobility shift assay revealed that curcumin prolonged the stress-induced activation of the heat shock element-binding (HSE-binding) activity of heat shock transcription factor (Hsf) in the cultured cells. The stimulatory effect of curcumin on the responses to stress was also observed in BRL-3A rat liver cells and Swiss 3T3 mouse fibroblasts. Induction of Hsp27, alphaB crystallin and Hsp70 in the liver and adrenal glands of heat-stressed (42 degrees C for 20 min) rats was also enhanced by prior injection of curcumin (20 mg/kg body weight). As curcumin is a potent inhibitor of arachidonic acid metabolism, it is suggested that the mechanism of the stimulation by curcumin of the stress responses might be similar to that of salicylate, indomethacin and nordihydroguaiaretic acid.

3T3 Cells↗
PubMed1998

[An experience of treatment of double positive myeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA) and anti-glomerular basement membrane antibodies in Goodpasture's syndrome onset of crescentic glomerulonephritis].

A 68-year-old woman was admitted to Kinki University Hospital because of progressive renal failure. She had been well until two months before admission. Laboratory data were as follows: serum creatinine 4.1 mg/dl, BUN 69 mg/dl, MPO-ANCA 33 EU, anti-glomerular basement membrane antibodies (AGBMA) 118 U. Histological findings showed cellular and fibrocellular crescents in many glomeruli. Therefore, we diagnosed rapidly progressive glomerulonephritis (RPGN) due to MPO-ANCA and anti-GBM associated renal disease. The patient was started on prednisolone and double filtration plasmapheresis (DFPP) therapy. Subsequently, the values of MPO-ANCA and AGBMA decreased. However, the patient's condition suddenly worsened and she died of interstitial pneumonia. Autopsy examination revealed crescentic glomerulonephritis and alveolar hemorrhage with linear deposition of IgG along the glomerular and alveolar capillary walls by immunofluorescence studies. We considered this to be a rare case of Goodpasture's syndrome associated with not only anti-GBM antibodies, but also MPO-ANCA.

Aged↗
PubMed1997

TCR in Fas-sensitive T cells from labial salivary glands of patients with Sjögren's syndrome.

Apoptosis is found in labial salivary glands of patients with Sjogren's syndrome (SS). To analyze the pathogenesis of apoptosis in labial salivary glands of SS patients, we examined the expression of Fas Ag and Fas ligand (FasL) and TCR on T cells susceptible to anti-Fas mAbs (CH-11). Fas Ag is expressed on epithelial cells and mononuclear cells in the salivary glands as observed by an immunohistochemical method. FasL is over-expressed specifically on T cells infiltrating into the labial salivary glands as seen by an reverse transcription-PCR method. These results suggest that apoptosis in SS lips is mediated by a Fas/FasL pathway. PCR single-strand conformation polymorphism (SSCP) clearly demonstrated that more than 40% of the T cells accumulated in labial salivary glands are deleted by incubation with CH-11 for 24 h in vitro, indicating that these expanded cells are Fas sensitive. junctional sequence analysis showed that the same conserved amino acid motifs (LAGG, RLA, SLG, QGPG, PGG, GGE, RGR, KPG, AGD, and MLG) in complementarity determining region 3 (CDR3) are found in Fas-sensitive T cell clones, whereas they are not detected in Fas-resistant clones, suggesting that Fas-sensitive T cells recognize restricted T cell epitopes on autoantigens. In conclusion, the findings suggest that Fas-sensitive T cells in labial salivary glands of SS patients are generated by Ag stimulation and might function as autoreactive T cells.

Amino Acid Sequence↗
PubMed1997

Th1 and Th2 subsets equally undergo Fas-dependent and -independent activation-induced cell death.

Stimulation of previously activated T cells results in apoptosis, termed activation-induced cell death (AICD). Recent analysis revealed that the Fas/Fas ligand (FasL) interaction is predominantly involved in AICD of T cells. Furthermore, based on the analysis of various T cell clones and lines, it has been reported that FasL is expressed mainly in Th1 but not in Th2 cells. However, the exact expression pattern of FasL and its function in normal activated T cells has not been determined. In the present study, by utilizing completely differentiated Th1 and Th2 cell populations obtained from ovalbumin-specific T cell receptor (TCR)-transgenic mice, the FasL expression on Th1 and Th2 was determined. Furthermore, involvement of Fas-FasL interaction in AICD of Th1 and Th2 cells was analyzed by two approaches: one was the inhibition of AICD by anti-FasL monoclonal antibodies, and the other AICD of Th1/Th2 subsets from TCR-transgenic mice backcrossed to lpr mice. We demonstrated that Th2 cells express FasL on the cell surface at a level similar to that expressed by Th1 cells, and that both subsets were equally susceptible to the Fas-mediated AICD. These observations suggest not only that the expression of FasL is not always correlated with Th subsets as defined by the cytokine-producing profile, but also that the responses of both Th1 and Th2 subsets are regulated by Fas-mediated AICD. Finally, analysis of the kinetics of AICD revealed a novel Fas/FasL-independent pathway in its initial stage. These findings revealed the precise function of Fas/FasL-mediated as well as Fas/FasL-independent AICD in the regulation of helper T cell responses.

Animals↗
PubMed1997

Granulocyte-macrophage colony-stimulating factor and IL-5 activate mitogen-activated protein kinase through Jak2 kinase and phosphatidylinositol 3-kinase in human eosinophils.

Mitogen-activated protein (MAP) kinases are activated by the sequential activation of Ras, Raf, and MEK (MAP kinase kinase) and regulate a wide variety of cell functions. To determine the kinase cascade for granulocyte-macrophage colony-stimulating factor (GM-CSF)- and IL-5-induced MAP kinase activation in eosinophils, we studied the effect of inhibitors of Jak2 kinase, tyrosine kinases, phosphatidylinositol 3-kinase, and protein kinase C on GM-CSF- and IL-5-induced MAP kinase activation in human eosinophils. GM-CSF and IL-5 activated 40, 42, and 44 kilodalton MAP kinase isoforms in eosinophils. This was indicated by the electrophoretic mobility shift of the three isoforms of MAP kinase in immunoblotting with anti-MAP kinase antibody and also by in-gel MAP kinase assay. MAP kinase activation was time- and dose-dependent, becoming maximal 3 to 15 minutes after stimulation. A Jak2 kinase inhibitor AG-490, a tyrosine kinase inhibitor genistein, and a phosphatidylinositol 3-kinase inhibitor wortmannin inhibited GM-CSF- and IL-5-induced MAP kinase activation in eosinophils, whereas a protein kinase C inhibitor staurosporine had a weak inhibitory effect. Furthermore, AG-490 and genistein prevented GM-CSF-induced tyrosine phosphorylation of Jak2 kinase in eosinophils. Taken together, these results indicate that GM-CSF and IL-5 activate MAP kinases through the signaling pathway of Jak2 kinase-tyrosine phosphorylated beta chain-phosphatidylinositol 3-kinase-Ras in eosinophils.

Androstadienes↗
PubMed1997

Immunotherapy with husband's leukocytes to primary habitual aborters and autoantibodies in their sera.

OBJECTIVE: This study was performed to determine whether primary habitual aborters have an autoimmunological tendency and whether immunotherapy with leukocytes induces autoantibodies in their sera. METHODS: We measured the levels of antiphospholipid antibodies (APAs) and antinuclear antibodies (ANAs) in the sera of 65 primary habitual aborters. Among them, 8 primary habitual aborters received immunotherapy with their respective husband's leukocytes; these 8 patients were followed up for autoantibodies in their sera before immunotherapy, at the time of pregnancy permission, during the first trimester of pregnancy, at delivery, and postpartum. RESULTS: Sixty-nine percent of the 65 primary habitual aborters were positive for IgG or IgM antibodies to at least 1 of 6 phospholipids, and 29% of them were positive for ANAs. Although the pregnancy outcomes of the 8 primary habitual aborters after immunotherapy were good, their APAs and ANAs converted to positive after the immunotherapy. CONCLUSION: Immunotherapy with leukocytes should be performed after checking and confirming the absence of autoantibodies in the sera of a habitual aborter.

Abortion, Habitual↗
PubMed1997

[Role of TCR V alpha 24 J alpha Q+ T cells in autoimmune diseases].

We investigated the role of T cell receptor (TCR) V alpha 24+ T cells in the pathogenesis of systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). The invariant V alpha 24 J alpha Q was expanded and comprised 50-90% of the total V alpha 24 in healthy individuals. In contrast, patients with SSc and SLE showed the selective reduction of the invariant V alpha 24 J alpha Q with oligoclonal expansion of V alpha 24 TCR other than V alpha 24 J alpha Q. Because human V alpha 24 J alpha Q TCR is analogous to murine invariant V alpha 14 J alpha 281 TCR which is the major genotype of NK T cells, these results suggest that the selective reduction of T cells with invariant V alpha 24 J alpha Q TCR might play an important role of the generation of autoreactive T cells including T cells bearing other V alpha 24 TCR in autoimmune disease patients.

Amino Acid Sequence↗