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Biomedical subjects

I Nakashima

Publications and source records attributed to I Nakashima.

At least 37 records · Page 2Linked to original sources
PubMed2001

T-cell-immunity-based inhibitory effects of orally administered herbal medicine juzen-taiho-to on the growth of primarily developed melanocytic tumors in RET-transgenic mice.

We examined the effect of oral administration of juzen-taiho-to, one of the most popular herbal medicines in Japan, on primary melanocytic tumor growth in RET-transgenic mice. There was virtually no difference between the lengths of tumor-free stages in the juzen-taiho-to-treated mice and the untreated littermate control mice. The rate of tumor growth in the juzen-taiho-to-treated mice, however, was greatly suppressed during the entire period after the initial tumor development. Correspondingly, the life span of juzen-taiho-to-treated transgenic mice was longer (over 6 mo in mean value) than that of control mice. We partially elucidated the mechanism of the antitumor effect of juzen-taiho-to. The addition of juzen-taiho-to at any of a wide range (50-1600 microg per ml) of concentrations to in vitro cultures of Mel-Ret cells, a malignant melanoma cell line derived from a RET-transgenic mouse, caused neither cell death nor cell cycle arrest directly. The addition of 50-400 microg per ml of juzen-taiho-to to cultures of murine spleen cells, however, promoted their DNA synthesis. More importantly, peritoneal exudate cells from the juzen-taiho-to-treated transgenic mice, in which the ratio and number of T cells were increased, displayed an antitumor immunity against Mel-Ret cells in vitro. Interestingly, the peritoneal-exudate-cell-associated antitumor immunity was further augmented by the addition of 200-400 microg per ml of juzen-taiho-to in vitro. This immunity, which was primarily conveyed by Thy-1+ T cells, was antigen (RET/melanoma) specific and cytotoxic. Amongst various chemical ingredients of juzen-taiho-to examined in this study, glycirrhizin displayed an action, partially replacing that of juzen-taiho-to, in promoting anti-Mel-Ret immunity when supplementarily added in vitro. These results suggest that juzen-taiho-to suppresses once-developed primary melanocytic tumors through potentiation of T-cell-mediated antitumor cytotoxic immunity in vivo.

Administration, Oral↗
PubMed2001

Osmotic stress-mediated activation of RET kinases involves intracellular disulfide-bonded dimer formation.

We showed that osmotic stress induces activation of c-RET and second-set activation of constitutively activated RET-MEN2B. A few percentage of RET proteins normally formed disulfide-bonded dimers in the cell, and osmotic stress promoted formation of these dimers. The disulfide-bonded dimers displayed higher levels of autophosphorylation and catalytic activity per molecule than did monomers. Osmotic stress also promoted activation and disulfide-bonded dimerization of the extracellular domain-depleted mutant RET (RET-PTC-1), suggesting that the target amino acid(s) for dimerization is located intracellularly rather than in the cysteine-rich region of the extracellular domain. In the mutant c-RET and RET-PTC-1 in which Cys987 of c-RET or Cys376 of RET-PTC-1 was replaced with Ala, the levels of intrinsic kinase activity were greatly reduced and barely increased in response to osmotic stress. Correspondingly, the Cys376-defective RET-PTC-1 did not form any demonstrable levels of dimers even after exposure to osmotic stress. In contrast, another RET-PTC-1 mutant that had a replacement of Cys365 with Ala mostly behaved like parental RET-PTC-1. These results suggest that Cys987 of c-RET or Cys376 of RET-PTC-1 plays a crucial role in maintenance and promotion of dimerization and activation of the RET kinases.

3T3 Cells↗
PubMed2001

Mice lacking interleukin-2 (IL-2)/IL-15 receptor beta chain are susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar choleraesuis but mice lacking IL-2 are resistant.

Interleukin-2 (IL-2)/IL-15 receptor beta (IL-15R beta)(-/-) mice were susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar Choleraesuis, whereas IL-2(-/-) mice were resistant. A natural killer cell response was not evident for both types of deficient mice. A Th1 response was detected in IL-2(-/-) but not in IL-2/IL-15R beta(-/-) mice infected with Salmonella, suggesting that IL-2/IL-15R beta signaling is important for the generation of protective Th1 cells.

Animals↗
PubMed2001

[Transverse myelopathy with renovascular hypertension caused by fibromuscular dysplasia].

An 18-year-old woman developed subacute transverse myelopathy with renovascular hypertension, hyperlipidemia, and proteinuria. Spinal magnetic resonance imaging(MRI) showed an intra-spinal cord lesion with severe spinal cord swelling at the C 2-Th 2 level. Increased plasma and cerebrospinal fluid interleukin-8(IL-8) levels and the presence of serum antineutrophil cytoplasmic antibody(ANCA) suggested the existence of an ischemic lesion due to vasculitis. Administration of corticosteroids ameliorated the clinical symptoms and MRI findings. Renovascular angiogram revealed the presence of fibromuscular dysplasia(FMD) at the left renal artery but no malformation was found at the cervical arteries. We discussed the possibility of relationships between myelopathy, FMD, IL-8, and ANCA.

Adolescent↗
PubMed2000

Isolation of the regulatory regions and genomic organization of the porcine alpha1,3-galactosyltransferase gene.

BACKGROUND: Alpha1,3-galactosyltransferase (alpha1,3GT) is an enzyme that produces carbohydrate chains termed alphaGal epitopes found in most mammals, although some species of higher primates, including human, are notable exceptions. The evolutionary origin of the lost alpha1,3GT enzyme activity is not yet known, although it has been suggested that the promoter activity of this gene in the ancestors of higher primates was inactivated. METHODS: We used 5'-or 3'-RACE, GenomeWalking, reverse transcriptase polymerase chain reaction (RT-PCR) and dual Luciferase reporter assay for identification of the full-length cDNA, which includes the transcription initiation site and the promoter region of porcine alpha1,3GT gene. RESULTS: The region around exon 1 is guanine and cytosine (GC)-rich (about 70%), comprising a CpG island spanning more than 1.5 kbp. The 5'-flanking region of exon 1 contains multiple transcription factor consensus motifs, including GC-box, SP1, AP2, and GATA-box sites, in the absence of TATA or CAAT-box sequences. The entire gene consists of three 5' noncoding and six coding region exons spanning more than 52 kbp. Detailed analysis of alpha1,3GT transcripts revealed two major alternative splicing patterns in the 5'-untranslated region (5'-UTR) and evidence for minor splicing activity that occurs in a tissue-specific manner. Interspecies comparison of 5'-UTR shows minimal homology between porcine and murine sequences except for exon 2, which suggests that the regulatory regions differ among species. CONCLUSIONS: These observations have important implications for experiments involving genetic manipulation of the alpha1,3GT gene in transgenic animals in terms of promoter utilization, and particularly in genetically engineering cells for the animal cloning technology by nuclear transfer.

Animals↗
PubMed2000

Significant correlation between IL-10 levels and IgG indices in the cerebrospinal fluid of patients with multiple sclerosis.

We measured the interleukin (IL)-6 and IL-10 levels in the plasma and the cerebrospinal fluid (CSF) of a total of 23 relapsing multiple sclerosis (MS) patients [18 with conventional form of MS (C-MS) and 5 with optic-spinal form of MS (OS-MS)] using ELISA and correlated them with the IgG indices and oligoclonal IgG bands (OB) to determine whether these cytokines play a role in the intrathecal immunoglobulin production. IL-10 values in the CSF significantly correlated with the IgG indices and tended to be higher in OB-positive patients. In contrast, IL-10 values in the plasma and IL-6 values in the CSF and the plasma did not correlate with the IgG indices or OB. The CSF-IL-10 value in OS-MS were much lower than those of C-MS, but those of CSF IL-6 did not differ between C-MS and OS-MS. The results remained unchanged even when OS-MS patients were excluded. Our results may suggest a role of IL-10 in upregulating the intrathecal IgG synthesis in relapsing MS.

Adult↗
PubMed2000

Arsenite induces apoptosis of murine T lymphocytes through membrane raft-linked signaling for activation of c-Jun amino-terminal kinase.

Because of its dual roles in acute toxicity and in therapeutic application in cancer treatment, arsenic has recently attracted a renewed attention. In this study, we report NaAsO(2)-induced signal cascades from the cell surface to the nucleus of murine thymic T lymphocytes that involve membrane rafts as an initial signal transducer. NaAsO(2) induced apoptosis through fragmentation of DNA, activation of caspase, and reciprocal regulation of Bcl-2/Bax with the concomitant reduction of membrane potential. We demonstrated that NaAsO(2)-induced caspase activation is dependent on curcumin-sensitive c-Jun amino-terminal kinase and barely dependent on SB203580-sensitive p38 kinase or PD98059-sensitive extracellular signal-regulated kinase. Additionally, staurosporine, which severely inhibited the activation of mitogen-activated protein (MAP) family kinases and c-Jun, partially blocked the NaAsO(2)-mediated signal for poly(ADP-ribose) polymerase (PARP) degradation. Potentially as the initial cell surface event for intracellular signaling, NaAsO(2) induced aggregation of GPI-anchored protein Thy-1 and superoxide production. This Thy-1 aggregation and subsequent activation of MAP family kinase and c-Jun and the degradation of PARP induced by NaAsO(2) were all inhibited by DTT, suggesting the requirement of interaction between arsenic and protein sulfhydryl groups for those effects. beta cyclodextrin, which sequestrates cholesterol from the membrane rafts, inhibited NaAsO(2)-induced activation of protein tyrosine kinases and MAP family kinases, degradation of PARP, and production of superoxide. In addition, beta cyclodextrin dispersed NaAsO(2)-induced Thy-1 clustering. These results suggest that a membrane raft integrity-dependent cell surface event is a prerequisite for NaAsO(2)-induced protein tyrosine kinase/c-Jun amino-terminal kinase activation, superoxide production, and downstream caspase activation.

Animals↗
PubMed2000

A protective role of interleukin-15 in a mouse model for systemic infection with herpes simplex virus.

To define the role of cytokine binding to the IL-2/IL-15R beta chain in protective immunity against systemic infection with herpes simplex virus type 2 (HSV-2), IL-2/IL-15 receptor(R)beta knock-out mice were inoculated intraperitoneally with HSV-2 strain 186. IL-2/IL-15R beta-deficient mice were susceptible to systemic HSV-2 infection compared with their heterozygous littermates. The emergence of natural killer (NK) cells was impaired in IL-2/IL-15R beta knock-out mice, but CD4(+) T cell receptor (TCR) alpha beta(+) T cells were normally detected in the peritoneal cavity after infection with HSV-2. However, the generation of HSV-2-specific CD4(+) T helper (Th) 1 cells producing interferon-gamma was impaired in IL-2/IL-15R beta knock-out mice following HSV-2 infection. The serum IL-15 level in control mice was increased in the early stage after HSV-2 infection but was not detectable in IL-2/IL-15R beta knock-out mice. In vivo administration of recombinant IL-15 protected normal mice from HSV-2-induced lethality, accompanied by increases in numbers of NK cells and HSV-2-specific Th1 cells. Taken together, these results suggest that IL-15, using the IL-2/IL15R beta chain, plays an important role in mounting protective immunity during the course of systemic HSV-2 infection.

Animals↗
PubMed2000

Mercuric chloride stimulates distinct signal transduction pathway for DNA synthesis in a T-cell line, CTLL-2.

Exposure of an interleukin-2 (IL-2)-dependent murine T-cell line (CTLL-2) to mercuric chloride in in vitro culture induced a low but definite level of DNA synthesis in the absence of exogenous IL-2, and further enhanced the IL-2-induced DNA synthesis. Addition of anti-IL-2 or anti-IL-4 antibody to the culture, which neutralized all of the IL-2 or IL-4 activity, respectively, never inhibited the mercuric chloride-mediated DNA synthesis. Correspondingly, no detectable level of IL-2, IL-4, and IL-15 mRNA was found in mercuric chloride-treated CTLL-2 cells in our test condition. Stimulation of CTLL-2 cells with IL-2 induced phosphorylation on extracellular signal-regulated kinases more intensively than on c-Jun NH2-terminal kinases (JNKs), and provoked tyrosine phosphorylation of Janus kinases (JAKs) and signal transducers and activators of transcription (STATs). In contrast, by mercuric chloride stimulation, JNKs and c-Jun were preferentially phosphorylated, but no detectable level of phosphorylation was induced on JAKs and STATs. These findings provided a possibility that mercuric chloride promoted lymphocyte proliferation through a JNK-linked signal cascade in CTLL-2 cells, which differs from that triggered by IL-2.

Animals↗
PubMed2000

Clustered cysteine residues in the kinase domain of v-Src: critical role for protein stability, cell transformation and sensitivity to herbimycin A.

We have previously reported the activation of Src by mercuric chloride based on the sulfhydryl modification. To evaluate the significance of cysteine residues in v-Src, we replaced each cysteine to alanine by oligonucleotide-directed mutagenesis and examined its effect on cell transformation. Of ten cysteine residues scattered over v-Src, four cysteines clustered in kinase domain, Cys483, Cys487, Cys496 and Cys498, were important for protein stability and cell transformation, whereas those in SH2 domain were dispensable. A single mutation in Cys498 yielded suppression of kinase activity and a temperature-sensitivity in anchorage independent growth. Double mutation either in Cys483/Cys487 or in Cys496/Cys498 yielded clear temperature-sensitivity in cell transformation and in stability of Src protein. Instability of Src protein was magnified by quadruple mutation in the cysteines, which decreased the half-life of Src to be less than one quarter of that of wild-type. In addition, both Cys483/Cyr487 and Cys496/Cys498 kinases became resistant to in vitro inactivation by herbimycin A, which directly inactivates v-Src in addition to its effect on HSP90. Taken together, our results strongly suggest that the cysteine clustered motif of v-Src are critical for protein stability, cell transformation and in vitro inactivation by herbimycin A.

Amino Acid Sequence↗
PubMed2000

Local levels of soluble tumor necrosis factor receptors in patients with allergic rhinitis are regulated by amount of antigen.

OBJECTIVES: To examine the possible correlation between the amount of antigen and the level of soluble tumor necrosis factor receptor (sTNFR), and to assess its biologic significance in allergic reactions. DESIGN: Randomized control trial. SUBJECTS: Twelve volunteers with Japanese cedar pollinosis and 10 healthy volunteers. INTERVENTIONS: The levels of p55 sTNFR (sTNFR1) and p75 sTNFR (sTNFR2) in samples of serum and nasal epithelial lining fluid (ELF) from 12 subjects with pollinosis and 10 healthy subjects were measured 4 times (preseason, early season, midseason, and postseason) in low (total, 415/cm( 2) per season) and high (total, 19,935/cm(2) per season) pollen-count periods, and the results were compared among the 4 groups. RESULTS: In the low-pollen-count period, increased levels of sTNFR1 and sTNFR2 were observed in ELF samples from the allergic subjects during the midseason. In contrast, in the high-pollen-count period, those levels were already elevated during the preseason and reduced during the midseason. Especially, the levels of sTNFR2 in ELF samples from the allergic subjects during the midseason in the high-pollen-count period were significantly lower than those in the low-pollen-count period. Moreover, a significant negative correlation (sTNFR1, R = -0.82; sTNFR2, R = -0. 73) was found between the levels of sTNFR1 and sTNFR2 in ELF samples and the scores of symptoms in the allergic subjects in the high-pollen-count period, but not in the low-pollen-count period. CONCLUSION: In patients with pollinosis, the amounts of antigen regulate the local levels of sTNFRs, possibly inhibiting nasal allergic inflammation.

Adult↗
PubMed2000

Methylglyoxal induces apoptosis in Jurkat leukemia T cells by activating c-Jun N-terminal kinase.

Methylglyoxal (MG) is a physiological metabolite, but it is known to be toxic, inducing stress in cells and causing apoptosis. This study examines molecular mechanisms in the MG-induced signal transduction leading to apoptosis, focusing particularly on the role of JNK activation. We first confirmed that MG caused apoptosis in Jurkat cells and that it was cell type dependent because it failed to induce apoptosis in MOLT-4, HeLa, or COS-7 cells. A caspase inhibitor, Z-DEVD-fmk, completely blocked MG-induced poly(ADP-ribose)polymerase (PARP) cleavage and apoptosis, showing the critical role of caspase activation. Inhibition of JNK activity by a JNK inhibitor, curcumin, remarkably reduced MG-induced caspase-3 activation, PARP cleavage, and apoptosis. Stable expression of the dominant negative mutant of JNK also protected cells against apoptosis notably, although not completely. Correspondingly, loss of the mitochondrial membrane potential induced by MG was decreased by the dominant negative JNK. These results confirmed a crucial role of JNK working upstream of caspases, as well as an involvement of JNK in affecting the mitochondrial membrane potential.

Animals↗
PubMed2000

Optic-spinal form of multiple sclerosis and immune-mediated myelopathy in Japan.

Optic-spinal form of multiple sclerosis (OS-MS) and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) are two immune-mediated myelopathy relatively common in Japan. (1) Transverse myelitis, once seen in 60% of MS, mostly OS-MS, 30 years ago, drastically decreased (5%) recently in Japan. In contrast, frequency of conventional form of MS (C-MS) increased during this period of time. But unlike C-MS in white patients, cerebellar hemispheric lesions are uncommon in Japanese C-MS. These findings emphasize influence of changes in exogenous factors on manifestations of MS and distinct genetic factors related to MS in Japanese and white patients. (2) To clarify the reason of high HTLV-I proviral load in HAM/TSP, we studied cellular immune surveillance against HTLV-I and found that significant cytotoxic T lymphocyte activity, and suppressed natural killer activity and antibody-dependent cell-mediated cytotoxicity in the patients. These altered immune surveillance may be associated with the spread of HTLV-I infection and the pathogenesis of HAM/TSP.

Asian People↗
PubMed2000

A short peptide derived from the antisense homology box of Fas ligand induces apoptosis in anti-Fas antibody-insensitive human ovarian cancer cells.

We found that a short synthetic peptide corresponding to the "antisense homology box" of Fas ligand induced apoptotic cell death of Fas-expressing human ovarian cancer cell lines. The peptide was deduced from residues 256-265 of human Fas ligand, based on the hypothesis that it should contain a specific binding site to the corresponding Fas. Interestingly, the ovarian cancer cell line NOS4, which was sensitive to anti-Fas antibody induced apoptosis, was not affected by the peptide, whereas another cell line, SKOV-3, which was insensitive to anti-Fas antibody, was killed by the peptide. Thus, this short peptide was shown to have a unique activity to induce apoptosis in human ovarian cancer cells in a manner different from anti-Fas antibody.

Antibodies, Monoclonal↗