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T Sasakawa

Publications and source records attributed to T Sasakawa.

At least 19 recordsLinked to original sources
PubMed2000

FK506 suppresses neutrophil chemoattractant production by peripheral blood mononuclear cells.

To understand the mechanism of action of FK506 (Tacrolimus) on neutrophil chemotaxis, we examined its effect on human neutrophil chemotaxis and neutrophil chemoattractant production by peripheral blood mononuclear cells. FK506 and cyclosporin A had no direct suppressive effect on neutrophil chemotaxis induced by interleukin-8, leukotriene B(4), complement 5a (C5a), zymosan-activated serum and formyl-Met-Leu-Phe (fMLP). FK506 and cyclosporin A only slightly suppressed the chemotactic activity of platelet-activating factor (PAF). Dexamethasone did not inhibit the chemotactic activity of any chemoattractant. The supernatant of peripheral blood mononuclear cells stimulated with anti-CD3 and CD2 antibodies induced neutrophil chemotaxis. FK506 and cyclosporin A suppressed the chemotactic activity of the supernatant in parallel to the suppression of interleukin-8 production by peripheral blood mononuclear cells. Anti-interleukin-8 antibody completely suppressed the chemotactic activity of the supernatant without drugs. These studies indicate that FK506 may exert a beneficial effect on human inflammatory diseases by suppressing neutrophil chemotaxis secondary to inhibition of chemoattractant (for example, interleukin-8) production by leukocytes.

Cells, Cultured↗
PubMed2000

FK506 potently inhibits T cell activation induced TNF-alpha and IL-1beta production in vitro by human peripheral blood mononuclear cells.

The aim of this study was to elucidate the in vitro inhibitory potency of FK506 on production of the inflammatory cytokines, tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta, with a view to assessing this immunosuppressive agent as a potential anti-rheumatic drug. We employed an in vitro model which produces TNF-alpha and IL-1beta through T cell activation. Human peripheral blood mononuclear cells (PBMC) were cultured with immobilized anti-CD3/CD28 monoclonal antibody in this model. FK506 inhibited anti-CD3/CD28 induced TNF-alpha and IL-1beta production at concentrations less than 1 ng ml(-1). Flow cytometric analysis of intracellular TNF-alpha and IL-1beta positive cells showed that FK506 potently suppresses inflammatory cytokine production from CD14+ monocytes as well as from T cells. Cyclosporin A (CsA) and dexamethasone (DEX) also inhibited the anti-CD3/CD28 induced cytokine production, but were less potent than FK506. FK506 and CsA, but not DEX, specifically inhibited anti-CD3/CD28 induced inflammatory cytokine production without affecting the lipopolysaccaride (LPS) induced effect. Methotrexate (MTX) was completely inactive for suppressing cytokine production under either condition. Anti-CD3/CD28 stimulated PBMC culture supernatants were found to enhance the expression of adhesion molecules in human vascular endothelial cells. FK506, CsA and DEX led to the suppression of adhesion molecule expression probably by inhibiting cytokine production from PBMC. The inhibitory potency of agents on TNF-alpha and IL-1beta production was compared with cytotoxicity and FK506 was not cytotoxic at concentrations several orders of magnitude greater than those required for cytokine inhibition. These results strongly suggest that FK506 may be most effective to specifically prevent T cell activation mediated inflammatory cytokine production in a clinical setting.

Antibodies↗
PubMed1997

Cloning and sequencing of cDNA encoding NG,NG-dimethylarginine dimethylaminohydrolase from rat kidney.

Three cDNA clones encoding NG,NG-dimethylarginine dimethylamino-hydrolase (EC 3.5.3.18) have been isolated from a rat kidney lambda gt11 library using a probe prepared by PCR on the basis of partially determined amino-acid sequences of the enzyme. The sequence analyses of the cDNAs established that the 3008 bp cDNA contains 855 bp open reading frame encoding 285 amino acids (M(r) 31414), 3'-flanking region (1722 bp) and 5'-flanking region (431 bp). The amino-acid sequences of all the peptides isolated from the purified enzyme were shown to be included in the deduced amino-acid sequence. Northern blotting analyses showed that the mRNA (4 kb) is ubiquitously expressed in various rat tissues.

Amidohydrolases↗
PubMed1995

Production of functional chick liver HMG 2a protein in Escherichia coli.

An efficient Escherichia coli system for the production of a variant form of high-mobility group-2a protein (HMG 2a), having the additional 5 amino acid residues (Ala-Pro-Thr-Leu-Glu) at the NH2-terminal, has been constructed. cDNA encoding HMG 2a was ligated with the Omp A signal peptide sequence and was inserted into an inducible bacterial expression vector pSH-L. After the plasmid introduced into E. coli was expressed by temperature shift, the recombinant product was purified by trichloacetic acid precipitation followed by Bio-Rex 70 column chromatography. The purified product showed the expected NH2-terminal sequence and the superhelical activity of circular DNA similar to the authentic HMG 2a isolated from chick liver.

Amino Acid Sequence↗
PubMed1995

Activated immunocompetent cells in rat colitis mucosa induced by dextran sulfate sodium and not complete but partial suppression of colitis by FK506.

Administration of dextran sulfate sodium (DSS) solutions to rats induced colitis which resembled mucosal lesions of human ulcerative colitis. Recent reports have shown that some cytokines are related to the pathogenesis of ulcerative colitis. In the present report, we describe the production of two cytokines in colitis mucosa in this DSS model. Using a cytotoxicity assay and a radioimmunoassay, we observed significant increases in levels of tumor necrosis factor-alpha (TNF-alpha) in the colitis mucosa and detected interleukin-1 alpha in the mucosa of 3 of 5 DSS rats and an increase in TNF-alpha had a tendency to be inhibited by treatment with FK506. Immunohistochemical investigation of DSS mucosa showed that the number of activated T cells increased at the earlier phase of inflammation. Luminol-dependent chemiluminescence values and myeloperoxidase activities were increased in the late phase of colitis and were suppressed by the FK506 treatment. These findings may support the role of TNF-alpha and T-cell activation in the pathogenesis of DSS colitis.

Animals↗
PubMed1995

Activated CD4+ and CD8+ cells in the colonic mucosa of ulcerative colitis patients: their relationship to HLA-DR antigen expression on the colonic epithelium and serum soluble CD25 levels.

This study was performed to clarify the relationship between activated (HLA-DR-expressing) CD4+ and CD8+ cells in the colonic lamina propria of ulcerative colitis and other immunological factors, i.e., epithelial DR expression, serum soluble CD25 levels, and colonic mucosal CD25+ cells. The frequency of epithelial DR expression was positively correlated with the numbers of CD4+ and CD8+ cells. The percentages activated CD4+/CD4+ cells were higher in mucosae with DR- epithelium than in mucosae with DR+ epithelium. The serum soluble CD25 levels were increased in ulcerative colitis, and there was an inverse correlation between these levels and the relative number of activated CD4+ cells in untreated active disease. These results suggest that interactions among mucosal CD4+ cells, colonic epithelium, and serum soluble CD25 might play an important role in the pathogenesis of ulcerative colitis.

Adolescent↗
PubMed1995

Study of cytokines in ulcerative colitis.

We investigated the lymphocyte-activation antigens and the expression of cytokine genes in the mucosa of ulcerative colitis (UC). Fresh colonic mucosal biopsy specimens from patients with UC and controls were fixed for the immunohistochemical study of CD4, HLA-DR, and CD25, and other specimens were prepared for the RNA analysis of cytokines. Gene expression was evaluated by the reverse transcription-polymerase chain reaction, and the radioactivity of dot-blotted amplified cDNA was standardized by co-amplified beta-actin cDNA. The inflamed mucosa of active UC showed increased CD4+DR+ and CD25+ cells in comparison with control subjects. Active UC showed significantly increased mRNA expression of IL-1 beta, IL-2R alpha, IL-6, IL-8, and TNF alpha compared with the controls. We found no significant difference in the mRNA expression for IL-2, IL-4, IL-10, and IFN-gamma between active UC and controls. Increased CD4+DR+ and CD25+ cells in active UC mucosa indicate mucosal CD4(+) T cell activation in the lamina propria, but we did not clarify Th1 or Th2 specific T cell activation from our study of cytokine mRNA expression. The increased mRNA expression for IL-1 beta, IL-6, and TNF alpha in the mucosal lesions of UC indicates that these inflammatory cytokines may play important roles in the pathogenesis of UC.

Biopsy↗
PubMed1993

Developmental changes in the expression of HMG 2a protein.

The levels of HMG 2a chromosomal protein and its mRNA change during the post-hatched development of chicks were investigated. The contents of both HMG 2a and 2b proteins of liver, heart, brain, muscle and gizzard were abundant in the newly hatched chicks but their contents decreased significantly in those tissues of the 70-day-old chicks. The HMG 2a mRNA levels of liver, heart and brain in 70-day-old chick decreased to about 40% of those mRNA in the newly hatched chicks while the HMG 2a mRNA levels of muscle and gizzard in the 70-day-old chicks increased 5- and 3-fold, respectively. These results suggest that the decrease in the HMG 2a protein contents of the muscle and gizzard in the 70-day-old chicks may be largely due to the stimulation of HMG 2a protein degradation or the reduction of HMG 2a mRNA translation.

Animals↗
PubMed1992

Molecular cloning of chick liver HMG 2a cDNA and developmental expression of HMG 2a mRNA.

The cDNA clone encoding HMG 2a of chick liver was isolated from a lambda gt11 expression library using polyclonal antibodies. DNA sequence analysis revealed an open reading frame of 201 amino acids. Comparison of the nucleotide sequences of cDNA coding for chick liver HMG 2a with pig thymus HMG 2 and human monocytic leukemia cell HMG 2 showed 70% homology. 2.0 kb and 1.2 kb mRNAs were found in newly hatched chick liver and decreased during postnatal development of chicks.

Amino Acid Sequence↗
PubMed1992

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Journal Article↗