K Tamoto

Gunma University, Maebashi, Gunma Prefecture, Japan

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Publications (46)137.61 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Atherosclerosis is a chronic inflammation disease characterized by acidic micromilieu and the accumulation of numerous bioactive lipid mediators, such as lysophosphatidic acid (LPA) and prostaglandins, in the atherosclerotic lesion. Chronic acidification induced various effects on vascular smooth muscle cells, but the molecular mechanisms underlying these effects remain unknown. In this study, we examine the role of proton-sensing ovarian cancer G protein-coupled receptor 1 (OGR1) in extracellular acidification-induced regulation of cyclooxygenase (COX)-2 induction, PGI(2) production, MAPK phosphatase (MKP)-1 expression, and plasminogen activator inhibitor (PAI)-1 expression and proliferation in human aortic smooth muscle cells (AoSMCs). Experiments with knockdown with small interfering RNA specific to OGR1 and specific inhibitors for G proteins showed that acidification-induced COX-2 expression, PGI(2) production, and MKP-1 expression, but not PAI-1 expression and inhibition of proliferation, were dependent on OGR1 and mainly mediated by G(q/11) protein. LPA remarkably enhanced, through the LPA(1) receptor/G(i) protein, the OGR1-mediated vascular actions to acidic pH. In conclusion, acidic pH-induced vascular actions of AoSMCs can be dissected to OGR1-dependent and -independent pathways: COX-2 expression, PGI(2) production, and MKP-1 expression are mediated by OGR1, but PAI-1 expression and inhibition of proliferation are not. LPA, which is usually thought to be a proatherogenic lipid mediator, may exert antiatherogenic actions under acidic micromilieu through cross-talk between LPA(1)/G(i) protein and OGR1/G(q/11) protein.
    AJP Heart and Circulatory Physiology 09/2010; 299(3):H731-42. · 3.63 Impact Factor
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    ABSTRACT: Disks of probucol and solid dispersion systems of probucol-polyvinylpyrrolidone (PVP) in various weight ratios were prepared. Dissolution of probucol was markedly increased in the solid dispersion systems in J.P. XV disintegration media No. 1 (pH 1.2) and No. 2 (pH 6.8). The concentrations of probucol after the dissolution of the disks of solid dispersion systems showed supersaturation. Following the administration of disks of solid dispersion systems in rabbits, a marked increase in the area under the plasma concentration time curve (AUC) was observed. When the weight ratio of PVP to probucol was larger, a larger AUC was observed. When disks of the 1 : 9 solid dispersion system (weight ratio of probucol : PVP=1 : 9) containing 50 and 100 mg probucol were respectively administered, AUC values were approximately proportional to the dose. AUC values following the administration of disks of the 1 : 9 solid dispersion systems containing 15 mg probucol (total weight: 150 mg) and 500 mg probucol were approximately equal. The mean half life (t(1/2)) was 12 h when disks of the 1 : 9 solid dispersion system were administered, whereas the t(1/2) was 35 h when probucol disks were administered. The markedly increased dissolution of probucol in solid dispersion systems resulted in a marked increase in its bioavailability.
    Biological & Pharmaceutical Bulletin 11/2009; 32(11):1880-4. · 1.85 Impact Factor
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    ABSTRACT: While inflammatory cytokines are well-recognized critical factors for the induction of cyclooxygenase-2 (COX-2) in activated fibroblast-like synovial cells, the roles of biologically active components other than inflammatory cytokines in synovial fluid remain unknown. Herein, we assessed the role of lysophosphatidic acid (LPA), a pleiotropic lipid mediator, in COX-2 induction using synovial fluid of patients with rheumatoid arthritis (RA) in fibroblast-like RA synovial cells. Synovial fluid from RA patients stimulated COX-2 induction, which was associated with prostaglandin E(2) production, in RA synovial cells. The synovial fluid-induced actions were inhibited by G(i/o) protein inhibitor pertussis toxin and LPA receptor antagonist 3-(4-[4-([1-(2-chlorophenyl)ethoxy]carbonyl amino)-3-methyl-5-isoxazolyl] benzylsulfanyl) propanoic acid (Ki16425). In fact, LPA alone significantly induced COX-2 expression and enhanced IL-1alpha- or IL-1beta-induced enzyme expression in a manner sensitive to pertussis toxin and Ki16425. RA synovial cells abundantly expressed LPA(1) receptor compared with other LPA receptor subtypes. Moreover, synovial fluid contains a significant amount of LPA, an LPA-synthesizing enzyme autotaxin, and its substrate lysophosphatidylcholine. In conclusion, LPA existing in synovial fluid plays a critical role in COX-2 induction in collaboration with inflammatory cytokines in RA synovial cells. Ki16425-sensitive LPA receptors may be therapeutic targets for RA.
    The Journal of Immunology 11/2008; 181(7):5111-9. · 5.52 Impact Factor
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    ABSTRACT: Acidosis has been shown to induce depletion of bone calcium from the body. This calcium release process is thought to be partially cell mediated. In an organ culture of bone, acidic pH has been shown to induce cyclooxygenase-2 (COX-2) induction and prostaglandin E(2) (PGE(2)) production, resulting in stimulation of bone calcium release. However, the molecular mechanisms whereby osteoblasts sense acidic circumstances and thereby induce COX-2 induction and PGE(2) production remain unknown. In this study, we used a human osteoblastic cell line (NHOst) to characterize cellular activities, including inositol phosphate production, intracellular Ca(2+) concentration ([Ca(2+)](i)), PGE(2) production, and COX-2 mRNA and protein expression, in response to extracellular acidification. Small interfering RNA (siRNA) specific to the OGR1 receptor and specific inhibitors for intracellular signaling pathways were used to characterize acidification-induced cellular activities. We found that extracellular acidic pH induced a transient increase in [Ca(2+)](i) and inositol phosphate production in the cells. Acidification also induced COX-2 induction, resulting in PGE(2) production. These proton-induced actions were markedly inhibited by siRNA targeted for the OGR1 receptor and the inhibitors for G(q/11) protein, phospholipase C, and protein kinase C. We conclude that the OGR1/G(q/11)/phospholipase C/protein kinase C pathway regulates osteoblastic COX-2 induction and subsequent PGE(2) production in response to acidic circumstances.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 08/2008; 23(7):1129-39. · 6.04 Impact Factor
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    ABSTRACT: Hyaluronan (HA), a high-molecular-weight glycosaminoglycan ubiquitously present in the extracellular matrices (ECMs) of animals, plays important roles in ECM organization and cell behavior through binding to hyaluronan-binding proteins (HABPs). We previously reported that HA has anti-inflammatory effects on guinea pig phagocytes, although the nature of guinea pig HABPs was unknown. In this study, we characterized guinea pig HABPs on peritoneal polymorphonuclear leukocytes (PMNs) and blood neutrophils by flow cytometry and affinity chromatography. It was found that PMNs express diverse HABPs with different molecular weights. These HABPs maximally bound with HA over a wide pH range (6-8), and recognized HAs as small as the pentadisaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine. Furthermore, they could be divided into Mg(2+)-dependent and Ca(2+)/Mg(2+)-independent groups. Interestingly, two proteins in the Mg(2+)-dependent group were found to be the two subunits of complement receptor type 3 (CR3, CD11b/CD18). Unlike PMNs, blood neutrophils expressed several functionally inactive HABPs. Among these inactive HABPs, Mg(2+)-dependent proteins including CR3 but not Ca(2+)/Mg(2+)-independent proteins were activated on phorbol ester-stimulation. These results show the existence of diverse HABPs on guinea pig neutrophils and the cell activation-dependent activation of HABPs. It is also suggested that the CR3-HA interaction is possibly involved in the regulation of neutrophil function.
    Journal of Biochemistry 02/2006; 139(1):59-70. · 3.07 Impact Factor
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    ABSTRACT: Sphingosine 1-phosphate (S1P) has been shown to exert a variety of biological responses through extracellular specific receptors or intracellular mechanisms. In the present study, we characterized a signaling pathway of S1P-induced cAMP accumulation in human coronary artery smooth muscle cells (CASMCs). S1P induced biphasic cAMP accumulation composed of a short-term and transient response (a peak at 2.5 min) and a late and sustained response ( approximately 4-6 h). The late phase of cAMP accumulation was parallel to the increment of cyclooxygenase-2 protein expression and was inhibited by N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS398), a cyclooxygenase-2-specific inhibitor. We were surprised to find that the cyclooxygenase-2 inhibitor also inhibited short-term cAMP accumulation even when cyclooxygenase-2 protein expression was not yet increased. More interestingly, the short-term cAMP accumulation was also completely inhibited by pertussis toxin, an inhibitor of G(i/o) proteins. JTE-013, a specific antagonist for S1P(2) receptors, inhibited the S1P-induced cAMP accumulation. Furthermore, small interfering RNAs targeted for S1P(2) receptors significantly inhibited the S1P-induced cAMP accumulation. The cAMP response was also inhibited by specific inhibitors for phospholipase C, extracellular signal-regulated kinase pathways, and cytosolic phospholipase A(2). S1P actually activated these enzyme activities and stimulated prostaglandin I(2) (PGI(2)) synthesis. Finally, exogenously applied arachidonic acid and PGI(2) induced cAMP accumulation to a similar extent as S1P. In conclusion, S1P induced cAMP accumulation through S1P receptors, including S1P(2) receptor and G(i/o) protein-mediated stimulation of intracellular signaling pathways involving cyclooxygenase-2-dependent PGI(2) synthesis.
    Molecular Pharmacology 05/2005; 67(4):1177-85. · 4.41 Impact Factor
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    ABSTRACT: Abstract Cerebrospinal fluid (CSF) induced neurite retraction of differentiated PC12 cells; the action was observed in 15 min (a rapid response) and the activity further increased until 6 h (a long-acting response) during exposure of CSF to the cells. The CSF action was sensitive to monoglyceride lipase and diminished by homologous desensitization with lysophosphatidic acid (LPA) and by pretreatment with an LPA receptor antagonist Ki16425. Although fresh CSF contains LPA to some extent, the LPA content in the medium was increased during culture of PC12 cells with CSF. The rapid response was mimicked by exogenous LPA, and a long-acting response was duplicated by a recombinant autotaxin, lysophospholipase D (lyso-PLD). Although the lyso-PLD substrate lysophosphatidylcholine (LPC) was not detected in CSF, lyso-PLD activity and an approximately 120-kDa autotaxin protein were detected in CSF. On the other hand, LPC but not lyso-PLD activity was detected in the conditioned medium of a PC12 cell culture without CSF. Among neural cells examined, leptomeningeal cells expressed the highest lyso-PLD activity and autotaxin protein. These results suggest that leptomeningeal cells may work as one of the sources for autotaxin, which may play a critical role in LPA production and thereby regulate axonal and neurite morphological change.
    Journal of Neurochemistry 03/2005; 92(4):904-14. · 3.97 Impact Factor
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    ABSTRACT: To investigate the mechanism of antirheumatic action of mizoribine (MZR), we examined the expression of matrix metalloproteinase-1 (MMP-1) and MMP-3 utilizing THP-1 derived macrophage-like cells (THP-1 macrophages) and human synovial fibroblasts (SFs). The cells were respectively stimulated with lipopolysaccharide (LPS) and interleukin-1beta in the presence or absence of MZR in vitro. The concentrations of MMP-1 and MMP-3 in the supernatant were measured by enzyme-linked immunosorbent assay. The secretion of MMP-1 from SFs, as well as THP-1 macrophages, was inhibited by MZR in a dose-dependent manner. Furthermore, a quantitative real-time polymerase chain reaction revealed that MZR decreased the expression of MMP-1 messenger RNA. These findings may be an explanation for the clinical effect of MZR in patients with rheumatoid arthritis.
    Modern Rheumatology 02/2005; 15(4):264-8. · 1.72 Impact Factor
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    ABSTRACT: Cytokines and growth factors in malignant ascites are thought to modulate a variety of cellular activities of cancer cells and normal host cells. The motility of cancer cells is an especially important activity for invasion and metastasis. Here, we examined the components in ascites, which are responsible for cell motility, from patients and cancer cell-injected mice. Ascites remarkably stimulated the migration of pancreatic cancer cells. This response was inhibited or abolished by pertussis toxin, monoglyceride lipase, an enzyme hydrolyzing lysophosphatidic acid (LPA), and Ki16425 and VPC12249, antagonists for LPA receptors (LPA1 and LPA3), but not by an LPA3-selective antagonist. These agents also inhibited the response to LPA but not to the epidermal growth factor. In malignant ascites, LPA is present at a high level, which can explain the migration activity, and the fractionation study of ascites by lipid extraction and subsequent thin-layer chromatography indicated LPA as an active component. A significant level of LPA1 receptor mRNA is expressed in pancreatic cancer cells with high migration activity to ascites but not in cells with low migration activity. Small interfering RNA against LPA1 receptors specifically inhibited the receptor mRNA expression and abolished the migration response to ascites. These results suggest that LPA is a critical component of ascites for the motility of pancreatic cancer cells and LPA1 receptors may mediate this activity. LPA receptor antagonists including Ki16425 are potential therapeutic drugs against the migration and invasion of cancer cells.
    Journal of Biological Chemistry 03/2004; 279(8):6595-605. · 4.65 Impact Factor
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    ABSTRACT: Lysophosphatidic acid (LPA) exerts a variety of biological responses through specific receptors: three subtypes of the EDG-family receptors, LPA1, LPA2, and LPA3 (formerly known as EDG-2, EDG-4, and EDG-7, respectively), and LPA4/GPR23, structurally distinct from the EDG-family receptors, have so far been identified. In the present study, we characterized the action mechanisms of 3-(4-[4-([1-(2-chlorophenyl)ethoxy]carbonyl amino)-3-methyl-5-isoxazolyl] benzylsulfanyl) propanoic acid (Ki16425) on the EDG-family LPA receptors. Ki16425 inhibited several responses specific to LPA, depending on the cell types, without any appreciable effect on the responses to other related lipid receptor agonists, including sphingosine 1-phosphate. With the cells overexpressing LPA1, LPA2, or LPA3, we examined the selectivity and mode of inhibition by Ki16425 against the LPA-induced actions and compared them with those of dioctyl glycerol pyrophosphate (DGPP 8:0), a recently identified antagonist for LPA receptors. Ki16425 inhibited the LPA-induced response in the decreasing order of LPA1 >/= LPA3 > LPA2, whereas DGPP 8:0 preferentially inhibited the LPA3-induced actions. Ki16425 inhibited LPA-induced guanosine 5'-O-(3-thio)triphosphate binding as well as LPA receptor binding to membrane fractions with a same pharmacological specificity as in intact cells. The difference in the inhibition profile of Ki16425 and DGPP 8:0 was exploited for the evaluation of receptor subtypes involved in responses to LPA in A431 cells. Finally, Ki16425 also inhibited LPA-induced long-term responses, including DNA synthesis and cell migration. In conclusion, Ki16425 selectively inhibits LPA receptor-mediated actions, especially through LPA1 and LPA3; therefore, it may be useful in evaluating the role of LPA and its receptor subtypes involved in biological actions.
    Molecular Pharmacology 10/2003; 64(4):994-1005. · 4.41 Impact Factor
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    ABSTRACT: In a human eosinophilic leukemia cell line, EoL-1, cell proliferation was suppressed by 2-day treatment with troglitazone. EoL-1 cells treated with troglitazone were arrested and maintained in the G0/G1 phase in the cell cycle. This suppression correlated with the up-regulation of mRNA for p21WAF1/CIP1 cyclin-dependent kinase (Cdk) inhibitor. The inhibitory effects of troglitazone on cell proliferation and expression of p21 mRNA were observed in a human myelomonocytic cell line, U937, and a human myelomonoblastic cell line, KPB-M15. In addition, in EoL-1 cells, p21 protein was induced by troglitazone treatment and the induction was inhibited by protein synthesis inhibitor, cycloheximide. These data suggest that troglitazone inhibits cell proliferation in myeloid leukemia cell lines at least in part by induction of p21 Cdk inhibitor.
    Biochemical and Biophysical Research Communications 09/1999; 261(3):833-7. · 2.41 Impact Factor
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    ABSTRACT: We measured the mRNA expression of the recently identified putative sphingosine 1-phosphate (S1P) receptors, i.e., Edg-1, AGR16/H218, and Edg-3, in HL-60 leukemia cells. Of these putative receptors, Edg-3 mRNA was abundantly expressed in undifferentiated HL-60 cells. Further, its mRNA expression was markedly downregulated by inducers of cell differentiation such as dibutyryl cAMP, retinoic acid, and 1alpha, 25-dihydroxyvitamin D3. The reduction of mRNA expression was associated with the attenuation of an S1P-induced increase in cytoplasmic free Ca2+ concentration. Thus, Edg-3, whose mRNA expression is downregulated during cell differentiation, may be responsible for the S1P-induced Ca2+ response in HL-60 leukemia cells.
    Biochemical and Biophysical Research Communications 01/1999; 253(2):253-6. · 2.41 Impact Factor
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    ABSTRACT: We examined the mechanism of action of lysophosphatidylcholine (LPC), which is suggested to be involved in the pathogenesis of atherosclerosis and inflammatory disorders, in HL-60 leukaemia cells. Extracellular 1-palmitoyl LPC increased the intracellular Ca2+ concentration in association with production of inositol phosphate. These actions of LPC were markedly inhibited by treatment of the cells with pertussis toxin and U73122, a phospholipase C inhibitor. The lipid-induced stimulation of the phospholipase C/Ca2+ system was also attenuated in the dibutyryl cAMP-induced differentiated (neutrophil-like) cells, in which phospholipase C activation induced by NaF or formyl-Met-Leu-Phe was enhanced. In contrast with the stimulatory action of 1-palmitoyl LPC, 1-stearoyl LPC was inhibitory for the phospholipase C/Ca2+ system stimulated by NaF as well as by 1-palmitoyl LPC or other Ca2+-mobilizing agonists. In a cell-free system, only an inhibitory effect on phospholipase C activity was observed even by 1-palmitoyl LPC; 1-stearoyl LPC was more inhibitive than 1-palmitoyl LPC. Taken together, these results suggest that atherogenic and inflammatory LPC exerts both stimulatory and inhibitory actions on the phospholipase C/Ca2+ system depending on the species of fatty acid residue of the lipid; the stimulatory effect is possibly mediated through G-protein-coupled receptors; the inhibitory effect might be caused by dysfunction of the components involved in the enzyme system owing to the amphiphilic nature of the lipid. 1-Palmitoyl LPC prefers the former receptor stimulation at least in intact cells, but 1-stearoyl LPC preferentially exerts the latter inhibitory action.
    Biochemical Journal 01/1999; 336 ( Pt 2):491-500. · 4.65 Impact Factor
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    ABSTRACT: 1Biosynthesis of CD11/CD18 in bovine leucocytes, intracellular Ca2+ ([Ca2+]i) signalling, chemiluminescent responses and membrane fluidity of neutrophils and the effects of D-mannose on neutrophils from control heifers and a heifer with bovine leucocyte adhesion deficiency (BLAD) were measured. The synthesis of CD11/CD18 complex was clearly detected in leucocytes from a normal heifer, but not in a BLAD-affected heifer. The transient phase of increased [Ca2+]i was clearly detected in neutrophils from a heifer with BLAD stimulated with opsonised zymosan, aggregated bovine immunoglobulin G or concanavalin A, whereas the sustained phase was deficient or significantly decreased compared with control heifers. [Ca2+]i signalling of neutrophils from control heifers and a heifer with BLAD stimulated with phorbol myristate acetate via an 11b/CD18-independent pathway showed no transient phase, and the subsequent increase in [Ca2+]i was almost identical in neutrophils from affected and control heifers. [Ca2+]i concentration and chemiluminescent responses of neutrophils from a control heifer were clearly decreased by treatment with anti-CD18 and anti-IgG antibodies. No differences in membrane fluidity were detected between neutrophils derived from control and CD18-deficient cattle. D-mannose binds mainly to Fc rather than CD18 receptors, and decreased Agg-IgG induced [Ca2+]i and the chemiluminescent response of neutrophils. The [Ca2+]i responses and Agg-IgG induced chemiluminescent responses of neutrophils from control heifers and a BLAD-affected heifer were inhibited by D-mannose. The characteristic changes of [Ca2+]i signalling and functional responses of B2-integrin-deficient neutrophils were demonstrated.
    Research in Veterinary Science 10/1996; 61(2):95-101. · 1.77 Impact Factor
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    ABSTRACT: Exogenous sphingosine 1-phosphate (S1P) induced Ca2+ mobilization, in association with an increase in inositol polyphosphate production reflecting activation of phospholipase C in HL60 leukemia cells. The increase in intracellular Ca2+ concentration ([Ca2+]i) induced by S1P was inhibited by an appropriate treatment of the cells with pertussis toxin (PTX), U73122 (a phospholipase C inhibitor) or phorbol 12-myristate 13-acetate (PMA). In parallel with the Ca2+ response, these agents also inhibited inositol polyphosphate production. The S1P-induced Ca2+ response was also attenuated in the dibutyryl cAMP-induced differentiated cells, where GTP-binding protein-induced Ca2+ response suggested to be enhanced. Lysophosphatidic acid (LPA) also increased [Ca2+]i in the cels, but the maximal response was about half of that of S1P, and furthermore PTX and dibutyryl cAMP treatment hardly affected the LPA-induced Ca2+ mobilization. We conclude that exogenous S1P mobilizes Ca2+ through phospholipase C activation. The S1P-induced enzyme activation is at least partly mediated by PTX-sensitive GTP-binding protein-coupled receptors which may be different from LPA receptors.
    FEBS Letters 03/1996; 379(3):260-4. · 3.58 Impact Factor
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    ABSTRACT: The adhesiveness of control and CD18-deficient bovine neutrophils on culture plates precoated with collagen I, collagen IV, fibronectin and laminin was measured to evaluate the possible factors for adherence to extracellular matrices. The release of N-acetyl-beta-D-glucosaminidase (NAGase) from control and CD18-deficient neutrophils stimulated with complement receptor type 3 (CR3) or Fc receptor dependent stimuli was also evaluated. The adhesive activities of CD18-deficient neutrophils to collagen I, collagen IV and fibronectin were significantly diminished (P < 0.05); however, similar adhesion to laminin was observed in CD18-deficient neutrophils and control neutrophils. The adhesive activity of control neutrophils on uncoated plates increased 2.5 times (P < 0.05) with the presence of PMA. The mean activities for NAGase release from CD18-deficient neutrophils stimulated with opsonized zymosan and aggregated bovine immunoglobulin G (Agg-IgG) were 46.7 and 82.7% that of the control neutrophils, respectively. The Agg-IgG-induced NAGase release from control and CD18-deficient neutrophils was eliminated by H7, a protein kinase C inhibitor. These results support that an association between CR3 and Fc receptors on neutrophils appears to play an essential role in neutrophil functions.
    Microbiology and Immunology 01/1996; 40(10):783-6. · 1.55 Impact Factor
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    ABSTRACT: Marked differences in bone marrow cellularity were observed between cattle affected with leukocyte adhesion deficiency (LAD) and control cattle. The number of nucleated cells in bone marrow was 2.9 to 8.8 times higher in cattle affected with LAD, compared with controls. The myeloid-to-erythroid ratio of bone marrow from 3 cattle affected with LAD ranged from 2.4 to 12. Deficient CD18 expression on neutrophils isolated from bone marrow of cattle with LAD was clearly detected by flow cytometric analysis. Neutrophils from bone marrow of cattle affected with LAD appeared round and not flat, after adherence to plastic wells under agarose, whereas neutrophils from bone marrow of clinically normal cattle were firmly spread on the surface of plastic wells. In the chemotaxis under-agarose assay, many pseudopodia were detected on bone marrow neutrophils from clinically normal cattle, but were not detected on bone marrow neutrophils from cattle with LAD. Activities of chemotactic movements and phagocytosis of neutrophils isolated from bone marrow of cattle affected with LAD were documented to be severely impaired.
    American Journal of Veterinary Research 03/1995; 56(2):167-71. · 1.35 Impact Factor
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    ABSTRACT: Expression of CD18 on bovine neutrophils in response to stimulation by zymosan activated serum (ZAS) and phorbol myristate acetate (PMA) and the effects of monoclonal antibodies (MAB) recognizing CD18 or bovine neutrophil surface antigens (S2G8 and S5F8G10) on adherence, chemotactic responses and phagocytosis of bovine neutrophils were evaluated. CD18 expression of neutrophils was increased after ZAS and PMA treatment by 12.2 and 54.2% respectively, and were significantly (p < 0.05, p < 0.01) different from those of untreated neutrophils. CD18 expression by neutrophils from a Holstein-Friesian heifer affected with leukocyte adhesion deficiency was within negative controls when stimulated by ZAS and PMA. Adherence, chemotactic responses, and phagocytosis were significantly decreased (p < 0.01) in neutrophils continuously treated with anti-CD18 MAB (MHM 23). Adherence was also significantly decreased in anti-CD18 pretreated neutrophils. Significant (p < 0.01) differences of chemotactic responses and phagocytosis of neutrophils were found between neutrophils pretreated and continuously treated with anti-CD18 MAB (MHM 23). Monoclonal antibodies to other surface antigens did not significantly alter neutrophil adherence, chemotaxis or phagocytosis. This study demonstrated that CD18 expression on bovine neutrophils is increased significantly by stimulation with ZAS and PMA and that the adhesion molecule CD18 plays an important role in adhesion-related functions.
    Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire 02/1995; 59(1):1-7. · 1.19 Impact Factor
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    ABSTRACT: The expression of Fc receptors for immunoglobulin G(IgG) and concanavalin A (con A)-binding receptors, luminol-dependent chemiluminescent (LDCL) responses, and the effect of anti-bovine IgG on LDCL responses were evaluated in neutrophils from Holstein calves with leukocyte adhesion deficiency (BLAD). Neutrophils from affected calves showed a 2.1- to 2.5-fold increase in Fc receptor expression compared with those of control calves by flow cytometric analysis. Con A-binding activities of neutrophils from affected calves were similar to those of control calves. Neutrophils from a calf with BLAD, when stimulated with zymosan opsonized with bovine serum (OPZ), heat-aggregated bovine IgG (Agg-bovine IgG), sheep red blood cells (SRBC) sensitized with anti-SRBC antibody (SRBC-anti-SRBC Ab), or con A had LDCL responses of 36 (P < 0.05), 77, 126 and 119% of peak LDCL values of controls, respectively. The NBT-reducing value of neutrophils from a calf with BLAD when stimulated with Agg-bovine IgG after pretreatment with anti-bovine IgG was 116.5% of the values of neutrophils from control calves, but the difference was not significant. The LDCL responses of neutrophils from a control calf and a calf with BLAD stimulated with OPZ were inhibited markedly by pre-incubation with anti-bovine IgG antiserum at concentrations ranging from 1.25 to 20 or 40 micrograms/ml. Although an increase in Fc receptor expression on neutrophils from calves with BLAD was observed, the LDCL responses stimulated with SRBC-anti-SRBC Ab and NBT-reducing activity stimulated with Agg-bovine IgG after pretreatment with anti-bovine IgG did not correlate significantly with the increased Fc receptor expression. These results support that neutrophil functions mediated by the Fc receptors are associated synergistically with the presence of the complement receptor type 3 (CR3)(CD11b/CD18).
    Microbiology and Immunology 01/1995; 39(9):703-8. · 1.55 Impact Factor
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    ABSTRACT: Lymphocyte functions in cattle affected with leukocyte adhesion deficiency (LAD, termed BLAD in cattle) were evaluated by lymphocyte markers, blastogenic response, and immunoglobulin concentrations; mononuclear phagocyte functions were assessed by chemotactic and luminol-dependent chemiluminescent (CL) responses to determine the effects of impaired expression of leukocyte CD18 on mononuclear cell functions. Deficient CD18 expression on lymphocytes and mononuclear phagocytes from cattle with BLAD was clearly detected by use of flow cytometric analysis. There were no significant differences in the population of peanut agglutinin (PNA)-positive and surface immunoglobulin-bearing blood lymphocytes from clinically normal cattle and cattle with BLAD, as determined by flow cytometric analysis. Lymphocytes from cattle with BLAD had strong mitogen-induced blastogenic responses, which were greater than those from controls. Adherence of mononuclear phagocytes from cattle with BLAD was markedly impaired, and their chemotactic responses had diminished values, compared with those of controls. Luminol-dependent CL of mononuclear phagocytes from affected cattle, stimulated by opsonized zymosan, had significantly (P < 0.01) decreased values, compared with those of controls. Concentrations of IgG were markedly increased in serum from cattle with BLAD, compared with those in controls. These results indicated that impaired expression of leukocyte CD18 has marked effects on adhering activity of mononuclear phagocytes, and significantly inhibits CL response of mononuclear phagocytes mediated by inactivated-complement 3b-dependent functions. High selective immunoglobulin concentrations indicated that lymphocytes of B-cell lineage may have normal function.
    American Journal of Veterinary Research 08/1994; 55(8):1101-6. · 1.35 Impact Factor

Publication Stats

639 Citations
137.61 Total Impact Points

Institutions

  • 2003–2010
    • Gunma University
      • Laboratory of Signal Transduction
      Maebashi, Gunma Prefecture, Japan
  • 2008
    • Tokushima Bunri University
      Tokusima, Tokushima, Japan
  • 1995–2006
    • Health Sciences University of Hokkaido
      • • Department of Immunology and Microbiology
      • • Division of Pharmaceutical Sciences
      • • Department of Microbiology
      Tōbetsu, Hokkaido, Japan
  • 1980–2005
    • Hokkaido University
      • • Department of Health Sciences
      • • Faculty of Pharmaceutical Sciences
      Sapporo, Hokkaidō, Japan
  • 1993–1995
    • Rakuno Gakuen University
      • Department of Veterinary Medicine
      Japan
  • 1988–1994
    • Higashi Nippon International University
      Isikari, Hokkaidō, Japan