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Biomedical subjects

M Miyasaka

Publications and source records attributed to M Miyasaka.

At least 19 recordsLinked to original sources

ADAMTS-1 cleaves a cartilage proteoglycan, aggrecan.

A disintegrin-like and metalloproteinase with thrombospondin type I motifs-1 (ADAMTS-1) is an extracellular matrix-anchored metalloproteinase. In this study we have demonstrated that ADAMTS-1 is able to cleave a major cartilage proteoglycan, aggrecan. N-terminal sequencing analysis of the cleavage product revealed that ADAMTS-1 cleaves the Glu(1871)-Leu(1872) bond within the chondroitin sulfate attachment domain of aggrecan. In addition, deletional analysis demonstrated that the C-terminal spacer region of ADAMTS-1 is necessary to degrade aggrecan. These results suggest that ADAMTS-1 may be involved in the turnover of aggrecan in vivo.

ADAM Proteins↗

Anergic T cells generated in vitro suppress rejection response to islet allografts.

BACKGROUND: Induction of antigen-specific unresponsiveness to grafts is the ultimate goal for organ transplantation. It has been shown that anergic T cells generated in vivo can be transferred as suppressor cells. Anergic cells generated in vitro have never been successfully used to prevent allograft rejection in vivo. We examined whether anergic cells generated in vitro by blocking CD28/B7 costimulatory pathway can suppress allograft rejection in vivo. METHODS: Anergic T cells were generated in vitro by the addition of anti-B7-1 and anti-B7-2 monoclonal antibodies (mAbs) to primary mixed lymphocyte reaction (MLR) consisting of C57BL/6 (B6) splenocytes as responder and irradiated BALB/c splenocytes as stimulator. We tested the ability of these cells to respond to various stimuli and to suppress alloreactive T-cell responses in vitro. For in vivo studies, 4x10(7) anergic cells were injected intravenously immediately after transplantation of BALB/c islets under the renal subcapsular space of streptozotocin-induced diabetic and 2.5-Gy X-irradiated B6 mice. RESULTS: Anergic cells treated with both mAbs in the primary MLR did not proliferate in secondary MLR against BALB/c and third-party C3H/He stimulators. The cells also failed to respond to immobilized anti-CD3 mAb, although they proliferated in response to concanavalin A or phorbol myristate acetate + ionomycin. The anergic state was reversed by the addition of exogenous IL-2. Furthermore, these cells suppressed the proliferation of naive B6 T cells against either the same (BALB/c) or third-party (C3H/He) stimulator cells. In in vivo studies, irradiated B6 mice rejected BALB/c islet allografts acutely with a mean survival time of 27.0+/-8.3 days, whereas two of six animals injected with the anergic cells accepted the allografts indefinitely (>100 days) with a mean survival time of 52.0+/-38.2 days. CONCLUSIONS: Anergic cells generated in vitro by blocking CD28/B7 costimulatory pathway suppress islet allograft rejection after adoptive transfer. This procedure might be clinically useful for promoting allograft survival.

Animals↗

Induction of unresponsiveness to islet xenograft by MMC treatment of graft and blockage of LFA-1/ICAM-1 pathway.

BACKGROUND: Induction of unresponsiveness to graft is one of major interest in xenotransplantation. Two different modalities [direct graft treatment by mitomycin C (MMC) and blockage of the lymphocyte function-associated antigen-1/intracellular adhesion molecule-1 (LFA-1/ICAM-1) pathway in recipients by species-specific mAbs] were tested for their ability to produce unresponsiveness to secondary islet xenografts. METHODS: Collagenase-digested WS (RT1k) rat islets, purified by Ficoll density gradient, were incubated for 30 min with MMC 10 microg/ml, cultured for 20 hr, and transplanted into the renal subcapsular space of streptozotocin-induced diabetic C57BL/6 (H-2b) mice. Recipient mice were divided into experimental groups according to anti-rat ICAM-1 and/or anti-mouse LFA-1 mAb treatment and transplantation of MMC-treated or nontreated islets. RESULTS: MMC pretreatment alone prolonged graft survival, with a mean survival time (MST) of 23.0+/-7.4 days, compared with that of cultured islets (12.4+/-2.7 days; P<0.01). MMC treatment of islets significantly augmented graft survival, compared with that of crude islet grafts under treatment with anti-donor ICAM-1 mAb (MST: >41.3+/-30 vs. 16.6+/-5.4 days, P<0.01), anti-recipient LFA-mAb (MST: >70.3+/-28.9 vs. 30.4+/-10.4 days, P<0.001), or both mAbs (MST: >88.1+/-24.1 vs. 23+/-7.4 days, P<0.0001). One of six, four of nine, and six of eight animals accepted MMC-treated islet xenografts over 100 days after treatment with anti-rat ICAM-1, anti-mouse LFA-1, or both mAbs treatments, respectively, whereas none of the animals accepted nontreated islets under the same treatment. When the mice bearing long-term functioning xenografts were challenged with the secondary graft from the original donor strain, the animals previously treated with anti-recipient LFA-1 and anti-donor ICAM-1 mAbs were more prone to accept it than animals given anti-recipient LFA-1 mAb alone (MST: 55.8+/-25.7 vs. 15+/-2.4 respectively; P<0.001), although they rejected the third-party xenograft and allograft acutely. CONCLUSIONS: In the xenogeneic islet transplantation model, MMC graft pretreatment and blockage of the ICAM-1/LFA-1 pathway constitute a potent protocol for inducing unresponsiveness to islet xenografts.

Animals↗

Stage-specific expression of mucosal addressin cell adhesion molecule-1 during embryogenesis in rats.

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is essential for lymphocyte trafficking to gut-associated lymphoid tissues and is implicated in inflammatory disorders in the gut and pancreatic islets. In this study, we examined the functional role of MAdCAM-1 during rat ontogeny using newly generated specific mAb. As previously observed in mice and humans, MAdCAM-1 was preferentially expressed in high endothelial venules (HEV) in gut-associated lymphoid tissues and venules of lamina propria in adult rats. Lymphocyte rolling and adhesion on HEV in Peyer's patches (PP) were completely abrogated with neutralizing anti-MAdCAM-1 mAb, in agreement with the notion that MAdCAM-1 is the principal HEV ligand for lymphocyte rolling and adhesion in adult PP. In the developing gastrointestinal tract, MAdCAM-1 was widely expressed in the venules of the lamina propria of fetal rats. In addition, MAdCAM-1 was also expressed in follicular dendritic cells in the neonatal PP. Interestingly, MAdCAM-1 expression was found also in nonmucosal tissues during ontogeny. MAdCAM-1 was transiently expressed in blood vascular endothelial cells in the fetal skin and neonatal thymus. Notably, MAdCAM-1-positive blood vessels were localized mainly in the cortico-medullary junction in the neonatal thymus and about 10-20% of thymocytes, most of which were either CD4, CD8 double positive or single positive specifically reacted with soluble MAdCAM-1 via integrin alpha4beta7. After birth, MAdCAM-1 expression in thymus blood vessels disappeared and concomitantly, the soluble MAdCAM-1-reactive thymocytes were rapidly down-regulated. Our results suggest that MAdCAM-1 functions as a vascular addressin in not only mucosal, but also nonmucosal lymphoid tissues during ontogeny.

Aging↗

Sulfatide and monoclonal antibodies prevent reperfusion injury in skin flaps.

Sulfatide binds to P- and L-selectin, which play important roles in the initiation of neutrophil-endothelial interactions. Sulfatide protects skin flaps from ischemia-reperfusion injury. The purpose of this study was to evaluate the augmented protection when anti-rat ICAM-1 and anti-rat LFA-1 antibodies are combined with sulfatide in the ischemia-reperfusion model of rat skin flaps. Sulfatide was administered intravenously just before elevation of the right abdominal epigastric flap, and monoclonal antibodies were injected 30 min before clamp release. The femoral artery and vein were clamped above and below the epigastric vessels for 11 h and then the clamp was released. The administration of both sulfatide and monoclonal antibodies significantly increased the flap surviving area (6.58 +/- 0.61 cm(2) versus the group with monoclonal antibodies alone, 4.43 +/- 0.32 cm(2), P = 0.01). In the untreated rats the area was 1.86 +/- 0.36 cm(2). Histological examination 24 h after reperfusion in the group treated with sulfatide and monoclonal antibodies showed only slight leukocyte invasion into the flap, and myeloperoxidase activity 24 h after reperfusion was significantly reduced. This study indicates that both sulfatide and monoclonal antibodies protect rat skin flaps from ischemia-reperfusion injury.

Animals↗

Mammary glands of Aly mice: developmental changes and lactation-related expression of specific proteins, alpha-casein, GLyCAM-1 and MAdCAM-1.

PROBLEM: (1) Aly mouse is an autosomal recessive mutant mouse that lacks lymph nodes and Peyer's patches. Defects of mammary glands might explain why these mice fail to nurture their pups. (2) Expressions of glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in mammary glands of lactating mice have been suggested, but only scant information is available. METHODS: The thickness and weight of mammary glands were measured directly. The expression of specific proteins, alpha-casein, GlyCAM-1, and MAdCAM-1 in mammary glands was detected by reverse transcription-polymerase chain reaction (RT-PCR). MAdCAM-1 expression was also confirmed by immunohistochemistry (IHC). RESULTS: Fat pads of mammary glands of homozygous (aly/aly) mice were small and weighed less than those of heterozygous (aly/+ ) mice. An increase in end-bud development was evident in aly/aly mice. During pregnancy, growth of the mammary gland and alveolar formation were noted in both groups. The expression of alpha-casein, GlyCAM-1 and MAdCAM-1 was detected in both groups of mice by RT-PCR from late-pregnancy. Immunohistochemically, MAdCAM-1 was noted in small vessels around the mammary globules. CONCLUSIONS: Our results demonstrated marked changes in the structure of the mammary glands of aly/aly mice. The expression of lactation-related proteins was detected during development, pregnancy, and lactation in both aly/aly and aly/+ mice.

Animals↗

Role of E-selectin in bleomycin induced lung fibrosis in mice.

BACKGROUND: Bleomycin (BLM), a well known anti-cancer drug, often causes acute lung injury and fibrosis by mechanisms that are not well understood. It is suspected that some proteases and active oxygen species generated from inflammatory cells cause the lung injury and subsequent lung fibrosis. It was therefore hypothesised that inhibition of adhesion of inflammatory cells to the endothelium might prevent these developments. METHODS: BLM (100 mg/kg) was injected into the tail veins of ICR mice to evaluate the induction of E-selectin, an adhesion molecule known to induce neutrophil attachment on endothelial cells. E-selectin mRNA induction was detected by reverse transcriptase polymerase chain reaction (RT-PCR). The myeloperoxidase (MPO) activities in the lung tissues of BLM treated and control mice were compared to evaluate neutrophil infiltration. Pathological changes in the lungs of soluble E-selectin transgenic mice (TG) and their TG negative (non-TG) littermates after BLM treatment were also compared. Serum samples of TG mice and non-TG mice were tested for their ability to block the binding of sialyl Lewis(x) to recombinant E-selectin in vitro. RESULTS: E-selectin mRNA was maximally induced at six hours after BLM treatment in the ICR mice. The soluble form of E-selectin which can competitively inhibit the binding of sialylated antigens on inflammatory cells to E- and P-selectins on the endothelium was detected in the serum of TG mice. BLM induced lung fibrosis occurred in non-TG mice but not in TG mice. This result confirms the finding that the serum of TG mice inhibits the binding of sialyl Lewis(x) to E-selectin in vitro. CONCLUSION: E-selectin plays an essential role in BLM induced lung fibrosis through the induction of neutrophil and other inflammatory cell accumulation, and soluble E-selectin may be of use in the prophylactic treatment of lung fibrosis.

Animals↗

Effect of ICAM-1 blockade on lung inflammation and physiology during acute viral bronchiolitis in rats.

Viral respiratory infections cause acute bronchiolitis and physiologic dysfunction in human infants and in animals. It is possible that the pulmonary dysfunction is a consequence of the inflammatory cells that are recruited during viral illness. We hypothesized that blockade of intercellular adhesion molecule-1 (ICAM-1), a major cell adhesion molecule, would impede the ingress of leukocytes during viral infection and attenuate virus-induced pulmonary dysfunction. Adult male rats were inoculated with parainfluenza type 1 (Sendai) virus or sterile vehicle, and treated with blocking or nonblocking MAb specific for rat ICAM-1. Respiratory system resistance, oxygenation (PaO2), methacholine responsiveness, and bronchoalveolar lavage (BAL) leukocyte counts were measured in anesthetized, paralyzed, ventilated rats. Treatment with the blocking ICAM-1 antibody reduced virus-induced increases in BAL neutrophils and lymphocytes by 70% (p < 0.001), but did not affect BAL monocytes/macrophages. Peripheral blood leukocyte counts were elevated in anti-ICAM-1 blocking antibody-treated rats (p = 0.0003). Although virus-induced increases in resistance and decreases in PaO2 were not affected by anti-ICAM-1 treatment, there was a small but significant attenuation of virus-induced methacholine hyperresponsiveness (p = 0.02). We conclude that ICAM-1 has an important role in neutrophil and lymphocyte infiltration during respiratory viral illness, and that virus-induced changes in pulmonary physiology are not related directly to the numbers of neutrophils and lymphocytes that migrate to the air spaces during infection.

Acute Disease↗

Sulfatide binding and activation of leukocytes through an L-selectin-independent pathway.

Sulfatide has been reported to activate leukocytes through L-selectin. Here we provide evidence that sulfatide binds to and activates leukocytes through both L-selectin-dependent and -independent pathways. Rat leukocytes of various sources shed surface L-selectin after phorbol myristate acetate (PMA) treatment, however, these cells retained the ability to bind sulfatide. In addition, sulfatide also bound to an L-selectin-negative cell line EL-4, and the binding was up-regulated by PMA. Sulfatide induced aggregation of L-selectin-positive lymphocytes, which was highly dependent on divalent cations, protein tyrosine kinases (PTK), and protein kinase C (PKC), but was independent of beta1 and beta2 integrins. In contrast, sulfatide-induced EL-4 cell aggregation required an LFA-1/ICAM-1 adhesion pathway but not PTK and PKC. A sulfatide receptor of 65 kDa was isolated from EL-4 cells. Taken together, this study suggests that sulfatide can bind to and activate leukocytes through an L-selectin-independent molecule and triggers signal transduction pathways different from those induced by L-selectin activation.

Animals↗

Molecular cloning of mXCR1, the murine SCM-1/lymphotactin receptor.

Single C motif-1 (SCM-1)/lymphotactin is a C-type member of the chemokine superfamily. Previously, we identified its specific receptor XCR1. Here we isolated the murine homologue of XCR1 (mXCR1). To demonstrate its biological activity, we produced recombinant mouse SCM-1 by the baculovirus expression system. B300-19 murine pre-B cells expressing mXCR1 responded to mSCM-1 in chemotactic and calcium-mobilization assays. mXCR1 mRNA was weakly expressed in spleen and lung of normal C57BL/6 mice. In spleen, CD8+ cells and NK1.1+ cells were found to express mXCR1. Identification of mXCR1 will now allow us to study the role of this unique cytokine system in the mouse models of inflammation and immunity.

Amino Acid Sequence↗

Development of a cell-free binding assay for rat ICAM-1/LFA-1 interactions using a novel anti-rat LFA-1 monoclonal antibody and comparison with a cell-based assay.

The importance of the interaction between lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) in the progression of inflammatory responses in vivo has been demonstrated mainly in rats. The present study was undertaken to develop binding assays suitable for measuring the rat ICAM-1/LFA-1 interaction in vitro. We first examined binding of rat T lymphoma FTL43 cells, which express LFA-1, to immobilized rat ICAM-1. Although FTL43 cells bound avidly to immobilized ICAM-1 and the binding was abolished with anti-LFA-1 monoclonal antibodies (mAbs), the binding was not completely inhibited by most anti-ICAM-1 mAbs. We next purified rat LFA-1 from FTL43 cells and constructed a cell-free binding assay. By using a newly developed anti-rat LFA-1 mAb RL14/9, which does not inhibit ICAM-1/LFA-1 interactions, binding of purified rat LFA-1 to immobilized ICAM-1 was successfully detected, whereas only a low signal to noise ratio was observed when binding of ICAM-1 to immobilized LFA-1 was examined. Moreover, we found that simultaneous addition of purified LFA-1 and biotinylated RL14/9 to ICAM-1-coated wells resulted in more sensitive detection of rat ICAM-1/LFA-1 binding. The binding was completely blocked with both anti-LFA-1 and anti-ICAM-1 mAbs and was much more sensitive to inhibition by the ICAM-1-IgG chimera, as compared with the cell-based assay. These results indicate that the cell-free binding assay provides a rapid and sensitive method for screening rat ICAM-1/LFA-1 antagonists, whose therapeutic effect on inflammatory diseases can further be evaluated in vivo.

Animals↗

Requirements for signal delivery through CD44: analysis using CD44-Fas chimeric proteins.

CD44 is a transmembrane glycoprotein involved in various cell adhesion events, including lymphocyte migration, early hemopoiesis, and tumor metastasis. To examine the requirements of CD44 for signal delivery through the extracellular domain, we constructed a chimeric CD44 protein fused to the intracellular domain of Fas on its C-terminus. In cells expressing the CD44-Fas fusion protein, apoptosis could be induced by treatment with certain anti-CD44 mAbs alone, especially those recognizing the epitope group d, which has been previously shown to play a role in ligand binding, indicating that ligation of a specific region of the CD44 extracellular domain results in signal delivery. Of note was that appropriate ligation of the epitope h also resulted in the generation of apoptotic signal, although this region was not thought to be involved in ligand binding. In contrast, the so-called blocking anti-CD44 mAbs (epitope group f) that can abrogate the binding of hyaluronate (HA) failed to induce apoptosis even after further cross-linking with the secondary Ab, indicating that a mere mAb-induced oligomerization of the chimeric proteins is insufficient for signal generation. However, these blocking mAbs were instead capable of inhibiting apoptosis induced by nonblocking mAb (epitope group h). Furthermore, a chimeric protein bearing a mutation in the HA binding domain and hence lacking the ability to recognize HA was incapable of mediating the mAb-induced apoptosis, suggesting that the functional integrity of the HA binding domain is crucial to the signal generation in CD44.

Animals↗

High endothelial cells synthesize and degrade sLex. Putative implications for L-selectin-dependent recognition.

L-selectin guides lymphocytes into peripheral lymphoid tissues by recognizing glycoprotein ligands decorated with 6-sulfated sialyl Lewis x (sulfo sLex). Here we have used a rat peripheral lymph node high endothelial cell line (Ax) to study in detail the synthesis, expression and degradation of sLex epitope. We show here that Ax cells possess active alpha(1,3)fucosyltransferase Fuc-TVII, the enzyme responsible for the final fucosylation of sialyl-N-acetyllactosamine during sLex synthesis, and express sLex on the cell surface. Furthermore, these cells degrade sLex, primarily by desialylating it to neutral Lex epitopes by alpha(2,3)sialidase(s).

Animals↗

Identification and characterization of ligands for L-selectin in the kidney. II. Expression of chondroitin sulfate and heparan sulfate proteoglycans reactive with L-selectin.

Ligands for the leukocyte adhesion molecule L-selectin are expressed not only in lymph node high endothelial venules (HEV) but also in the renal distal tubuli. Here we report that L-selectin-reactive molecules in the kidney are chondroitin sulfate and heparan sulfate proteoglycans of 500-1000 kDa, unlike those in HEV bearing sialyl Lewis X-like carbohydrates. Binding of L-selectin to these molecules was mediated by the lectin domain of L-selectin and required divalent cations. Binding was inhibited by chondroitinase and/or heparitinase but not sialidase. Thus, L-selectin can recognize chondroitin sulfate and heparan sulfate glycosaminoglycans structurally distinct from sialyl Lewis X-like carbohydrates.

Animals↗

L-selectin and its ligands mediate infiltration of mononuclear cells into kidney interstitium after ureteric obstruction.

It was previously reported that the L-selectin ligands detected by a rat L-selectin and human IgG chimeric molecule (rLEC-IgG) are expressed in the distal tubules of the kidney, where no leukocyte traffic is seen under physiological conditions. In the present study, the role of L-selectin ligands in leukocyte infiltration into the kidney interstitium was investigated using a rat ureteric obstruction model. After ligation of the ureter, ligands for L-selectin rapidly disappeared from tubular epithelial cells and were relocated to the interstitium and peritubular capillary walls, where infiltration of monocytes and CD8(+) T cells subsequently occurred. Mononuclear cell infiltration was significantly inhibited by intravenous injection of a neutralizing monoclonal antibody (MAb) against L-selectin, indicating the possible involvement of an L-selectin-mediated pathway. Interestingly, immunohistochemical studies with a MAb against sulphatide showed that the distribution of sulphatide, known to be one of the candidates of L-selectin ligand, was almost indistinguishable from the staining pattern of rLEC-IgG in both normal and ureteric obstructed kidneys, suggesting that sulphatide and/or related molecule(s) relocated to the renal interstitium were recognized by leukocyte L-selectin, leading to interstitial leukocyte infiltration. In line with this notion, intravenous injection of sulphatide markedly inhibited leukocyte infiltration, suggesting that L-selectin-sulphatide interaction may play a pivotal role in interstitial leukocyte infiltration in the kidney following ureteric obstruction.

Animals↗

Significant role of intragraft lymphoid tissues in preventing insulin-dependent diabetes mellitus recurrence in whole pancreaticoduodenal transplantation.

Graft recurrence of insulin-dependent diabetes mellitus (IDDM) was examined. Islet transplantation or pancreas-alone transplantation excluding the duodenum and peripancreatic lymph nodes was compared with whole pancreaticoduodenal transplantation. A Wistar Furth (WF; RT1(u), RT6.2) to major histocompatibility complex (MHC)-compatible diabetes-prone (DP; RT1(u), RT6.1 gene carrier)-biobreeding (BB) rat transplantation model was used. Only DP recipients that had been transplanted with whole pancreaticoduodenal grafts were free from IDDM recurrence (>60 days postgrafting) when treated with anti-intercellular adhesion moluecule-1 (ICAM)-1/leukocyte function-associated antigen-1 (LFA-1) monoclonal antibodies (mAbs). In the spleen cells of the DP rats that had accepted pancreatic grafts (60 days postgrafting), flow cytometric analysis showed that NKR-P1(+)TCRalphabeta(+) (NKT) cells had proliferated markedly, with the proportion of 12.8 +/- 1.7% in the total splenic T cells, most of which (86.2%) were derived from the donor (RT6.2(+)). By enzyme-linked immunonosorbent assay (ELISA), serum interferon gamma (IFN-gamma) was not detected (<13 pg/ml) in all rats. However, interleukin-4 (IL-4) was detected as 158.8 +/- 28.0 pg/ml in the nonrecurrent DP recipients. These data suggested that to prevent IDDM recurrence in the pancreatic graft, the lymphocytes in the pancreaticoduodenal grafts are necessary. Also, the donor-derived NKT cells might have some immunoregulatory functions with a Th2 deviation.

Animals↗

Characterization of an apparently conserved epitope in E- and P-selectin identified by dual-specific monoclonal antibodies.

E- and P-selectin recognize a wide and overlapping range of oligosaccharide ligands including sialyl-Lewis X (sLeX) through their highly homologous C-type lectin domains. We report that an epitope apparently conserved between E- and P-selectin is functionally involved in ligand recognition although distantly located from the conventional carbohydrate binding site. We found that a previously established anti-E-selectin monoclonal antibody (mAb), 1.2B6, is cross-reactive with P-selectin, and that the 1.2B6 epitope is in the C-type lectin domain and identical to or overlapping with an epitope recognized by other independently established anti-E- and P-selectin dual-specific mAb. The epitope has been mapped by others to a region distant from the previously identified carbohydrate binding site of E-selectin in its three-dimensional structure. Nevertheless, it is of note that all dual-specific mAb, including 1.2B6, inhibited E- or P-selectin-mediated cell adhesion and also binding to sLeX. Engagement of the apparently conserved epitope by the dual-specific mAb may lead to inhibition of the ligand binding ability of E- and P-selectin by a previously uncharacterized mechanism(s) rather than by direct inhibition of sLeX binding to the hitherto identified ligand binding site.

Animals↗