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Biomedical subjects

M Miyasaka

Publications and source records attributed to M Miyasaka.

At least 145 records · Page 8Linked to original sources
PubMed1996

The critical role of intercellular adhesion molecule-1 in Masugi nephritis in rats.

Intercellular adhesion molecule-1 (ICAM-1, CD54), an adhesion molecule of the immunoglobulin superfamily, is an endothelial cell surface ligand for such leukocyte integrins as lymphocyte-function-associated molecule 1 (LFA-1, CD11a/CD18), Mac-1 (CD11b/CD18) and CD43. These molecules mediate adhesive interactions between leukocytes and endothelial cells and are critically involved in infiltration of leukocytes into inflammatory lesions. We examined the expression of ICAM-1 in renal tissues of Masugi nephritis rats and directly examined the role of ICAM-1 by administration of neutralizing monoclonal antibodies (MAbs) to rat ICAM-1, LFA-1 alpha-subunit (LFA-1 alpha), beta-subunit (LFA-1 beta) and Mac-1 alpha-subunit (Mac-1 alpha). Within 3 h after injection of nephrotoxic serum, increased expression of ICAM-1 was detected in the glomeruli by in situ hybridization and an immunofluorescence study. Proteinuria was significantly suppressed by the MAbs against ICAM-1, Mac-1 alpha and LFA-1 beta. Neutrophil infiltration into the glomeruli was significantly prevented by injection of the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta. These results indicate that both ICAM-1/LFA-1 and ICAM-1/Mac-1 pathways are involved in neutrophil infiltration into the glomeruli. On the other hand, monocytic infiltration was prevented by the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta but not by anti-Mac-1 alpha MAb. Due to these results, ICAM-1 is considered to be a critical molecule involved in the pathogenesis of the leukocyte infiltration into the glomeruli in the heterologous phase of Masugi nephritis. Anti-ICAM-1 antibody may be beneficial in the treatment of leukocyte-mediated glomerular diseases.

Animals↗
PubMed1996

Apigenin inhibits tumor necrosis factor-induced intercellular adhesion molecule-1 upregulation in vivo.

OBJECTIVE: Apigenin is a flavonoid that effectively blocks intercellular adhesion molecule-1 (ICAM-1) upregulation and leukocyte adhesion in response to cytokines in vitro. In the present study, we characterized the effects of tumor necrosis factor (TNF) on ICAM-1 expression in different tissues of the rat. We then assessed whether apigenin alters this response. METHODS: ICAM-1 expression was measured under baseline conditions or 5 h after treatment with rTNF. We used 125I-labeled anti-rat ICAM-1 monoclonal antibody (mAb) and an isotype-matched control mAb labeled with 131I to correct for nonspecific accumulation of the binding mAb. Animals were pretreated with either placebo, apigenin, narigenin (a flavonoid without inhibitory effect in vitro), or vehicle. Additional groups of animals were treated with either allopurinol, glutathione, dimethyl-thiourea, or an anti-CD18 monoclonal antibody in order to assess possible actions of flavonoids that were mediated via free radical scavenging or through interference with neutrophil function. RESULTS: Treatment with rTNF resulted in a marked increase in ICAM-1 expression in all organs studied. The magnitude of the response varied in different organs and increases ranged from onefold (lung) to threefold (muscle). Treatment with apigenin blocked ICAM-1 upregulation in organs with low to intermediate responses to rTNF and it significantly attenuated the increased ICAM-1 expression in organs that normally exhibit more marked upregulation. Treatment with narigenin or vehicle did not affect rTNF-induced ICAM-1 upregulation in all tissues studied. Pretreatment with either allopurinol, free radical scavengers, or anti-CD18 monoclonal antibody did not affect the ICAM-1 upregulatory response to rTNF. CONCLUSIONS: TNF-induced ICAM-1 upregulation in vivo effectively is blocked by apigenin through a mechanism that is unrelated to free radical scavenging or leukocyte function.

Animals↗
PubMed1996

Protective effects of combined adhesion molecule blockade in models of acute lung injury.

In various models of lung inflammatory injury in rats, individual requirements for leukocytic and endothelial adhesion molecules have been established. In the current study dose-response interventions were employed and comparisons made to protective effects of single and dual blockade of adhesion molecules. In lung injury following systemic activation of complement, single blockade of P- or L-selectin produced dose-dependent protective effects, while combined blocking of L- and P-selectin produced protection that was incremental to either blockade alone but less than completely additive. The blocking of selectins seemed to have limited effects. Additive protective effects were also found with dual blockade of CD11a and CD11b. In the IgG immune complex model of lung injury, combined blocking of L- and E-selectin was more effective than blocking of either selectin alone. Combined blockade of CD11a and CD18 was also more effective than either blocking intervention alone. However, blocking of CD11b was ineffective and was not associated with increased protection when combined with anti-CD18, confirming earlier indications that, under the conditions employed, Mac-1 plays no measurable role in this model of lung injury. Increased protection also occurred when mAb to E-selectin was combined with mAb to either ICAM-1 or CD18. In the IgA immune complex model of lung injury the simultaneous blocking of E-selectin and ICAM-1 resulted in protection that was no different from the effects of blocking ICAM-1 alone, confirming that E-selectin plays no role in this model of lung injury. Dual blockade of CD11b and CD18 was more effective than blockade of either alone. Finally, combined blockade of CD18 and VLA-4 in the two models of immune complex-induced injury was more effective than individual blockade. These data substantiate the multiple requirements for adhesion molecules in the three models of lung injury. The findings raise questions as to why dual blockade of adhesion molecules produces less than completely additive effects of the individual interventions and why the protective effects of blocking antibodies seem to have an upper limit.

Animals↗
PubMed1996

Uptake of indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody in the allografted rat lung during acute rejection.

BACKGROUND: Although many methods for detection and quantification of allograft rejection of the lung have been explored, only histologic diagnosis by lung biopsies has gained widespread acceptance. To examine whether indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody imaging can noninvasively detect acute lung rejection, we measured the uptake of this radiopharmaceutical in lung tissue and with scintigraphy in orthotopically transplanted rat lungs. METHODS: The left lung transplant model was used with Lewis- to Wistar-King rat allografts and Lewis isograft controls. Lungs were harvested 2,3,4,5,6, and 7 days after transplantation. The transplanted and native lungs were removed 24 hours after injection of the radiotracer, weighed, and counted in a gamma well counter; uptake ratios of the transplanted or native lungs were then calculated, and scintigraphy was performed. RESULTS: Histologic rejection scores by the grading system of the International Society for Heart and Lung Transplantation at 2,3,4,5,6, and 7 in the allografts were 1.2 +/- 0.2, 2.3 +/- 0.6, 3.0 +/- 0.5, 3.7 +/- 0.4, and 4, and 4, respectively. The uptake ratios of the allografts 3,4, and 5 days after transplantation were significantly higher than the values of the respective isografts and correlated with histologic rejection grades. However, 6 days after transplantation, uptake ratios of allografts decreased and did not correlate with histologic grades. On days 3,4, and 5 after transplantation, the tracer uptake within the allografts was visualized by means of scintigraphy. CONCLUSIONS: We conclude that indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody increased during mild to moderate acute lung rejection. An abnormal scintigram with this radiotracer suggests that lung biopsy should be performed to exclude lung rejection.

Animals↗
PubMed1995

Constitutive overexpression of the L-selectin gene in fresh leukemic cells of adult T-cell leukemia that can be transactivated by human T-cell lymphotropic virus type 1 Tax.

L-selectin is an adhesion molecule of the selectin family that mediates the initial step of leukocyte adhesion to vascular endothelium. Upon cellular activation, expression of the L-selectin gene is downregulated at both the protein and mRNA levels. To understand the mechanism of leukemic cell infiltration into organs, we studied the expression and regulation of L-selectin mRNA in fresh leukemic cells of adult T-cell leukemia (ATL) patients and investigated the response of the L-selectin promoter to human T-cell lymphotropic virus type 1 (HTLV-1) Tax, which is a viral transcriptional transactivator. Flow cytometry showed that L-selectin was expressed on fresh ATL cells along with other activation antigens. Northern blot analysis showed that ATL cells overexpressed that L-selectin mRNA and that the level was aberrantly upregulated after PMA stimulation. Studies using in situ hybridization showed expression of the L-selectin mRNA in the infiltrating leukemic cells in the liver of two ATL patients. Intravenous injection of a rat T-cell line that overexpresses L-selectin showed increased organ infiltration. The induction of Tax expression in JPX9 cells resulted in about a twofold increase in the mRNA expression levels compared with the basal level. Chloramphenicol acetyltransferase (CAT) assay after transient cotransfection showed about a fivefold transactivation of the L-selectin promoter by Tax. The serum level of the shed form of L-selectin was significantly increased in ATL patients (mean +/- SD, 4,215.4 +/- 4,111 ng/mL) compared with those of asymptomatic carriers and healthy blood donors (mean +/- SD, 1,148.0 +/- 269.0 ng/mL and 991.9 +/- 224 ng/mL, respectively). These results indicated that ATL cells constitutively overexpress the L-selectin gene that can be transactivated by HTLV-1 Tax. The overexpression of L-selectin, as well as of inflammatory cytokines, by ATL cells may provide a basis for ATL cells to attach the vascular endothelium, leading to transmigration and organ infitration.

Adult↗
PubMed1995

De novo expression of endothelial sialyl Lewis(a) and sialyl Lewis(x) during cardiac transplant rejection: superior capacity of a tetravalent sialyl Lewis(x) oligosaccharide in inhibiting L-selectin-dependent lymphocyte adhesion.

Acute organ transplant rejection is characterized by a heavy lymphocyte infiltration. We have previously shown that alterations in the graft endothelium lead to increased lymphocyte traffic into the graft. Here, we demonstrate that lymphocytes adhere to the endothelium of rejecting cardiac transplants, but not to the endothelium of syngeneic grafts or normal hearts analyzed with the in vitro Stamper-Woodruff binding assay. Concomitant with the enhanced lymphocyte adhesion, the cardiac endothelium begins to de novo express sialyl Lewis(a) and sialyl Lewis(x) (sLea and sLex) epitopes, which have been shown to be sequences of L-selectin counterreceptors. The endothelium of allografts, but not that of syngeneic grafts or normal controls, also reacted with the L-selectin-immunoglobulin G fusion protein, giving further proof of inducible L-selectin counterreceptors. The lymphocyte adhesion to endothelium could be significantly decreased either by treating the lymphocytes with anti-L-selectin antibody HRL-1, or by treating the tissue sections with sialidase or anti-sLea or anti-sLex monoclonal antibodies. Finally, we synthetized enzymatically several members of the sLex family oligosaccharides and analyzed their ability to block lymphocyte adhesion to cardiac endothelium. The monovalent sLex (a tetramer), divalent sLex (a decamer), and tetravalent sLex (a 22-mer) could all significantly reduce lymphocyte binding, but the inhibition by the tetravalent sLex-construct was clearly superior to other members of the sLex family. The crucial control oligosaccharides, sialyl lactosamines lacking fucose but being otherwise similar to the members of sLex family, had no effect on lymphocyte binding.

Animals↗
PubMed1995

Control of the IL-2 responsiveness of B lymphocytes by IL-2 and IL-4.

A two-step culture system was used to analyze the parameters involved in the acquisition of IL-2 responsiveness by murine B cells. In the first culture, unstimulated, or resting, B cells prepared from spleen of naive animals were challenged during 48 h with IL-2, IL-4, anti-mu, anti-mu+IL-2, anti-mu+IL4, or anti-mu+IL-2 + IL-4. In a second culture, IL-2 responsiveness was followed by measuring either the cell proliferation or the Ig production. It was found that only B cells stimulated by anti-mu+IL-2 were able to respond. The expression of three chains of the IL-2 receptor (IL-2R alpha, IL-2R beta, and IL-2R gamma) was studied by FACS. IL-2R beta and IL-2R gamma were found to be expressed constitutively on resting B cells. IL-2R alpha was induced by anti-mu and anti-mu+IL-2 treatment. Although B cells treated by anti-mu alone are not able to respond to IL-2, they do express an IL-2 binding capacity comparable with B cells treated by anti-mu+IL-2. This paradoxical result suggests that IL-2 has a direct influence on the acquisition of the IL-2 responsiveness. IL-4 exerts a negative effect on the IL-2 response. At the molecular level, IL-4 was found to reduce selectively the IL-2R beta expression at the B cell surface. This effect was confirmed by Northern blot analysis. Maximum expression of the IL-2R beta mRNA is obtained after anti-mu+IL-2 treatment. In the presence of IL-4, expression of the IL-2R beta mRNA is greatly reduced.

Animals↗
PubMed1995

Up-regulation of lung vascular ICAM-1 in rats is complement dependent.

Intrapulmonary deposition of IgG immune complexes in rats causes acute inflammatory lung injury that is neutrophil, complement, cytokines (IL-1, TNF-alpha), and intercellular adhesion molecule (ICAM-1) dependent. In the current studies involving the same model of lung injury, complement depletion or complement blockade resulted in substantial reductions in up-regulation of pulmonary vascular ICAM-1, accompanied by reduced lung injury and neutrophil accumulation. Complement depletion neither reduced the amount of immune complex deposited in lung nor the TNF-alpha content in bronchoalveolar lavage fluids. In the same model of inflammatory lung injury, neutrophil depletion (which is highly protective) did not affect up-regulation of lung vascular ICAM-1. Up-regulation of lung vascular ICAM-1 by intratracheally administered TNF-alpha was also prevented by complement depletion. These studies indicate an unexpected in vivo relationship between complement and up-regulation of lung vascular ICAM-1.

Animals↗
PubMed1995

A novel ligand for CD44 is serglycin, a hematopoietic cell lineage-specific proteoglycan. Possible involvement in lymphoid cell adherence and activation.

The lymphocyte adhesion molecule CD44 recognizes a non-hyaluronate proteoglycan, gp600, secreted by mouse T cell line CTLL2. We now demonstrate that gp600 is identical to serglycin, a member of the small proteoglycan family stored in intracellular secretory granules of lymphoid, myeloid, and some tumor cells. Purified gp600 has the ability to bind specifically to CD44, and the binding is dependent on activation of CD44. The CD44-binding elements on gp600 or serglycin are glycosaminoglycans consisting of chondroitin 4-sulfate. Serglycin is readily exocytosed, and its interaction with active form CD44 augments the CD3-dependent degranulation of CD44 positive CTL clones. We conclude that the serglycin secreted from secretory granules of hematopoietic cells is a novel ligand for CD44, and could regulate lymphoid cell adherence and activation.

Amino Acid Sequence↗
PubMed1995

Compartmentalized roles for leukocytic adhesion molecules in lung inflammatory injury.

By using the model of acute injury caused by intrapulmonary deposition of IgG immune complexes, blocking mAb to CD11a, CD11b, L-selectin, and intercellular adhesion molecule-1 (ICAM-1) were administered either i.v. or intratracheally (i.t.). The effects of these interventions were assessed according to lung injury, lung content of myeloperoxidase (MPO), TNF-alpha, and cellular content in bronchoalveolar lavage (BAL) fluids, and up-regulation of pulmonary vascular ICAM-1. In animals treated i.v. with Abs to CD11a, L-selectin, or ICAM-1 lung injury was significantly attenuated in parallel with reduced lung content of MPO. Under similar conditions, treatment with anti-CD11b had no effect. However, when the same mAb were administered i.t., anti-CD11a and anti-L-selectin were without protective effects, whereas i.t. administered anti-CD11b and anti-ICAM-1 were each highly protective. The protective effects of anti-CD11b were related to profound reductions in BAL levels of TNF-alpha, pulmonary vascular up-regulation of ICAM-1, and lung content of MPO. The protective effects of i.t.-administered anti-ICAM-1 were not associated with reduced BAL levels of TNF-alpha. Protective effects of mAb were also reflected in reductions of retrievable neutrophils in BAL fluids. mAb to rat CD11b and CD18 but not to rat CD11a suppressed in vitro production of TNF-alpha by immune complex-stimulated rat alveolar macrophages. The mAb did not reduce NO2-/NO3- generation in stimulated macrophages but all mAb (except anti-ICAM-1) reduced O2- responses in macrophages. These data suggest a compartmentalized role for adhesion molecules in lung inflammatory injury after intraalveolar deposition of IgG immune complexes, with CD11a, L-selectin, and ICAM-1 being important in the vascular compartment for neutrophil recruitment, whereas in the alveolar compartment CD11b and ICAM-1 (but not CD11a and L-selectin) seem to play key roles.

Alveolitis, Extrinsic Allergic↗