Posttreatment neuropathy in diabetic subjects with mitochondrial tRNA (Leu) mutation.
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Adult↗
Biomedical subjects
Y Yazaki
Publications and source records attributed to Y Yazaki.
Expression of c-fms on smooth muscle cells isolated from experimental arteriosclerosis.
In the present study, we demonstrated gene transcription of c-fms in smooth muscle cells isolated from an experimental rabbit model of arteriosclerosis (intimal smooth muscle cells), although there was no gene transcription of c-fms detected in medial smooth muscle cells. On immunocytochemical analysis, both types of smooth muscle cells similarly reacted with an antibody specific to muscle cells (HHF 35), but did not react with an antibody specific to rabbit macrophages (RAM 11). Intimal smooth muscle cells bound to acetylated LDL and resulting foam cell formation was observed. In response to M-CSF, an increased rate of cell proliferation was observed in intimal smooth muscle cells, but not in medial smooth muscle cells. These results indicated that intimal smooth muscle cells have monocyte-macrophages characteristics such as the expression of c-fms and scavenger receptor gene.
Animals↗
[Biochemical tests for diagnosis of acute myocardial infarction and estimation of infarct size].
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Aspartate Aminotransferases↗
[Molecular diagnosis of dyslipoproteinemia].
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Humans↗
Establishment of enzyme-linked immunosorbent assays for lipoprotein lipase with newly developed antibodies.
We developed eight new antibodies against lipoprotein lipase (LPL), which included polyclonal antibodies raised against recombinant human LPL produced by transformant cells and two synthetic peptides corresponding to either amino (N)- or carboxy (C)-terminus of human LPL. With these antibodies, we established three effective sandwich enzyme-linked immunosorbent assays (ELISAs) for LPL, which enabled us to examine LPL mass not only in the postheparin plasma from human, rat, mouse, and guinea pig but also in the media and lysates of cultured cells. All of the developed antibodies showed high affinities for LPL, but their binding to LPL did not always influence the lipolytic activity of the enzyme. Interestingly, although the anti-C-terminus antibody should bind to a common epitope of human and mouse LPL, its binding selectively suppressed only human LPL activity. Because amino acid sequence surrounding the epitope is common to both LPLs, difference in the sequence outside the epitope will contribute to the selective suppression of LPL activity by the antibody. Our results also suggested that both termini of LPL would be exposed on the surface of the molecule because they were fully accessible to antibodies and that the N-terminus of LPL would be functionally less important because binding of the anti-N-terminus antibody did not affect human LPL activity. The ELISAs were further utilized to demonstrate the presence of C-terminus truncated LPL protein in the postheparin plasma of an LPL-deficient patient, to map an epitope of the anti-C-terminus antibody within residues 433-436, and to gain insight into the structure-function relationship of the LPL molecule.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Involvement of the renin-angiotensin system in the development of left ventricular hypertrophy and dysfunction.
OBJECTIVES: To elucidate the regulation of cardiac gene expression by mechanical stress and to analyse molecular mechanisms associated with the involvement of angiotensin II (Ang II) in the development of cardiac hypertrophy and dysfunction. METHODS: Neonatal rat cardiocytes were cultured in deformable silicone dishes, and mechanical stress was imposed on the cardiocytes by stretching them. In in vivo studies, spontaneously hypertensive rats (SHR) were treated with a non-peptide, specific Ang II type 1 receptor antagonist, TCV 116. RESULTS: Expression of c-fos was rapidly induced, and fetal type genes such as skeletal alpha actin and beta myosin heavy chain genes were re-expressed by stretching. The mechanical stress decreased the expression of Ca(2+)-ATPase in the sarcoplasmic reticulum. With regard to signals for the development of cardiac hypertrophy, mechanical stress evoked c-fos expression via the activation of protein kinase C. The phosphorylation cascade (sequential activation of protein kinase C, Raf-1 kinase, mitogen-activated protein kinase kinase, mitogen-activated protein kinase and S6 kinase), which may be involved in protein synthesis and gene expression, was activated by mechanical stress in cardiocytes. Stretch-induced cardiac cellular hypertrophy was partially inhibited by TCV 116. TCV 116 treatment of SHR reduced left ventricular weight, left ventricular wall thickness, myocyte transverse diameter, V3 myosin heavy chain levels and the interstitial collagen volume fraction. CONCLUSIONS: These results indicate that Ang II may, in part, mediate the stretch-induced hypertrophic growth of cardiomyocytes via the type 1 Ang II receptor.
Animals↗
Involvement of the renin-angiotensin system in the development of left ventricular hypertrophy and dysfunction.
OBJECTIVES: To elucidate the regulation of cardiac gene expression by mechanical stress and to analyse molecular mechanisms associated with the involvement of angiotensin II (Ang II) in the development of cardiac hypertrophy and dysfunction. METHODS: Neonatal rat cardiocytes were cultured in deformable silicone dishes, and mechanical stress was imposed on the cardiocytes by stretching them. In in vivo studies, spontaneously hypertensive rats (SHR) were treated with a non-peptide, specific Ang II type 1 receptor antagonist, TCV 116. RESULTS: Expression of the c-fos gene was rapidly induced, and fetal type genes such as skeletal alpha actin and beta myosin heavy chain genes were re-expressed by stretching. The mechanical stress decreased the expression of Ca(2+)-ATPase in the sarcoplasmic reticulum. With regard to signals for the development of cardiac hypertrophy, mechanical stress evoked c-fos expression via the activation of protein kinase C. The phosphorylation cascade (sequential activation of protein kinase C, Raf-1 kinase, mitogen-activated protein kinase kinase, mitogen-activated protein kinase and S6 kinase), which may be involved in protein synthesis and gene expression, was activated by mechanical stress in cardiocytes. Stretch-induced cardiac cellular hypertrophy was partially inhibited by TCV 116. TCV 116 treatment of SHR reduced left ventricular weight, left ventricular wall thickness, myocyte transverse diameter, V3 myosin heavy chain levels and the interstitial collagen volume fraction. CONCLUSIONS: These results indicate that AngII may, in part, mediate the stretch-induced hypertrophic growth of cardiomyocytes via the type 1 Ang II receptor.
Actins↗
Molecular analysis of the t(1;19)(q23;p13) translocation observed in adult leukemias.
We report three cases of adult leukemias with the t(1;19)(q23;p13) translocation, two with acute lymphoblastic leukemia (ALL:L2) and one with megakaryoblastic crisis of chronic myelocytic leukemia. Only one patient with ALL showed the same E2A/PBX1 fusion transcripts as those observed in childhood ALLs with the t(1;19) by RNA-based polymerase chain reaction. This patient survived for 8 months only from the time of his diagnosis. On the other hand, the other two cases were negative for the E2A/PBX1 fusion and one of them with ALL remains in remission. Our observations suggest that there could be heterogeneity in the molecular events among adult leukemias carrying the t(1;19) and that the E2A/PBX1 fusion formation might also be associated with an adverse treatment outcome in adult leukemias as in childhood leukemias.
Adolescent↗
Expression of histamine H2 receptor in Chinese hamster ovary cells: a probe to study the desensitization mechanism.
Canine histamine H2 receptor DNA, cloned by polymenase chain reaction (PCR), was transfected into Chinese hamster ovary cells using an expression vector. The expression of H2 receptors was demonstrated by immunoblotting with specific antibodies and the binding of tiotidine, an H2 receptor antagonist. H2 receptor-specific cAMP production was observed only in cells expressing canine H2 receptors. Preincubation of transfected cells with 10 microM histamine for 10 or 60 min at 37 degrees C decreased both the maximal response and the sensitivity of the subsequent histamine-stimulated cAMP production, showing desensitization. Under these circumstances, decreases in tiotidine binding without changes in affinity in intact cells and also in the membrane were observed, whereas there was no decrease in total H2 receptor number. Thus, desensitization of histamine H2 receptor was associated with the sequetration of receptors.
Animals↗
[Cytotoxic factor in vascular injury].
Cell-mediated autoimmunity has been strongly implicated in the pathogenesis of vascular injury in Takayasu's arteritis. Both cytotoxic T lymphocytes (CTLs) and natural killer (NK)cells, playing a major part in cell-mediated cytotoxicity, are thought to kill virus-infected cells or tumor cells with the effector molecules contained in their cytoplasmic granules, one of which is named pore-forming protein or perforin. Perforin is expected to play a central role in the granule exocytosis model of lymphocyte-mediated cytolysis, exhibited by CTLs and NK cells as well as gamma delta T lymphocytes. We found that perforin was expressed in these killer lymphocytes infiltrated in the aortic tissue of patients with Takayasu's arteritis. Immunoelectron microscopic study demonstrated that the infiltrating cells directly injured vascular cells by releasing perforin molecules, indicating the critical role of perforin in the vascular injury involved in Takayasu's arteritis.
Autoimmunity↗
Molecular cloning and analysis of the human Tec protein-tyrosine kinase.
Mouse Tec is a non-receptor type protein-tyrosine kinase and is highly expressed in many hematopoietic cell lines. To investigate the roles of the Tec kinase in the human hematopoietic system, we isolated cDNAs encoding the human Tec kinase. The human tec cDNAs can encode a peptide of 631 amino acid residues with a calculated molecular mass of 73,624. The predicted human Tec protein is highly homologous to those of the members of the Tec family including mouse Tec type IV (94% homology), mouse Tsk/Itk (60%), and human Btk (57%). The homology between human Tec and other members of the Tec family can be observed not only in the Src homology 3 (SH3), SH2, and kinase domains, but also in the N-terminal unique domain. Northern blot analysis demonstrated that the major transcripts of tec could be detected at 2.6 kb and 3.6 kb in a wide range of human hematopoietic cell lines including myeloid, B-, and T-cell lineages. Interestingly, high expression of the tec gene could be detected in all of the three patients examined with myelodysplastic syndrome. The human tec gene was mapped by fluorescence in situ hybridization (FISH) to chromosome 4p12.
Amino Acid Sequence↗
Tec protein-tyrosine kinase directly associates with Lyn protein-tyrosine kinase through its N-terminal unique domain.
Most of non-receptor-type protein-tyrosine kinases share common structures, such as N-terminal unique domains, Src homology region (SH)-2 domains, SH-3 domains and kinase domains. Although vast effort has brought some information about the in vivo roles of SH-2, -3 and kinase domains, little is still understood about the function of N-terminal unique domain. By utilizing the glutathione S-transferase (GST)-fusion system, we have investigated the role of N-terminal unique domain of the Tec protein-tyrosine kinase in a mouse IL-3-dependent myeloid cell line. We could reveal that the C-terminal half of the Tec N-terminal unique domain (NTec2 region) can bind to a set of tyrosine-phosphorylated cellular proteins in vitro in an IL-3-dependent manner. Surprisingly, p56/53Lyn constitutively binds to the NTec2 region. Among the NTec2-bound Lyn proteins, only the p56 form seems to be inducibly tyrosine-phosphorylated in response to IL-3. Binding domain of Lyn to the NTec2 region was localized to its SH-3 domain. Tec was also shown to make a stable complex with Lyn in vivo. This is the first report demonstrating the direct association between distinct cytoplasmic protein-tyrosine kinases, especially through N-terminal unique domain.
Amino Acid Sequence↗
[Cardiac sarcoidosis].
To analyze the clinical features of cardiac sarcoidosis, we reviewed case reports and clinical investigations from Japan and other countries. Female patients were more frequently affected in this disease in Japan. Cardiac sarcoidosis is characterized by a high incidence of complete atrioventricular block, right bundle branch block, and ventricular arrhythmias on the electrocardiogram. Echocardiography often reveals left ventricular dilatation with systolic dysfunction and wall thickening or thinning. Radionuclide testings, such as, thallium-201, gallium-67 or technetium-99m pyrophosphate, are useful for detecting cardiac involvement and evaluating efficacy of corticosteroid therapy in patients with sarcoidosis. Most of the patients died due to recurrent or refractory heart failure. It is noteworthy that cases of sudden death during stable cardiac function have become infrequent.
Cardiomyopathies↗
Human ltk receptor tyrosine kinase binds to PLC-gamma 1, PI3-K, GAP and Raf-1 in vivo.
Leukocyte tyrosine kinase (ltk) is a receptor-type tyrosine kinase which is suggested to be expressed in hematopoietic cells and neuronal cells in human. Recently we have cloned a full sized human ltk cDNA which has a 423 amino acid extracellular domain which may bind to unknown ligand(s), and a 415 amino acid cytoplasmic domain which contains a tyrosine kinase domain. To identify the cellular signal transducer proteins binding to the ltk protein, we have analysed the recombinant ltk protein transiently expressed in COS cells. By an in vitro immune complex kinase assay, a major 140 kDa phosphoprotein and other cellular phosphoproteins were co-immunoprecipitated with the 100 kDa ltk protein using anti-ltk monoclonal antibodies. Western blot analysis revealed that the wild-type ltk protein was tyrosine-phosphorylated in vivo and associated with SH2 containing proteins, PLC-gamma 1, p85 subunit of PI3-K and GAP, in vivo. Furthermore, the wild-type ltk protein also binds to a serine/threonine kinase, Raf-1, in vivo. In contrast, none of these signal transducer proteins were associated with a kinase-negative ltk mutant (K544M-ltk) in which methionine at the putative ATP binding site was replaced with lysine. These results suggest that the associations of the ltk protein with those signaling molecules depend on the tyrosine kinase activity of the ltk protein. This is the first detection of cytoplasmic signal transducers that bind to the ltk protein in vivo.
Base Sequence↗
The C-terminal SH3 domain of the mouse c-Crk protein negatively regulates tyrosine-phosphorylation of Crk associated p130 in rat 3Y1 cells.
We have isolated the mouse c-crk cDNA from a mouse liver cDNA library. It encodes 304 amino acids and consists mainly of SH2/SH3 regions. In Northern blot analysis, the mouse c-crk mRNA is expressed ubiquitously in every tissue and organ, suggesting that the c-Crk protein may be a common signal transducing molecule among tissues. In contrast to the v-Crk protein, which has a single SH3 domain, the c-Crk protein contains two, the more N-terminal SH3(1) domain and the C-terminal SH3(2) domain. To elucidate functions of these SH3 domains, we have constructed two c-crk mutants, B-crk and D-crk, which lack the SH3(2) and the SH3(1) domain, respectively. These mutants were expressed in rat 3Y1 cells, and examined for their transforming ability in terms of morphological phenotypes and for tyrosine phosphorylation profiles of cells expressing the mutant proteins. Morphological alteration and increased tyrosine phosphorylation of 130-140 kDa proteins, the major component of which is the Crk-associated p130, were observed in cells expressing B-Crk as well as those expressing v-Crk, but little in cells expressing c-Crk even at a similar level of expression. Although a highly tyrosine-phosphorylated form of the p130 was coimmunoprecipitated with c-Crk as well as B-Crk, the relative level of tyrosine phosphorylation of the p130, which is normalized to the amount of Crk protein immunoprecipitated, was 10 to 20 times higher in B-Crk-expressing cells than in c-Crk- or D-Crk-expressing cells. The present results indicate that the SH3(2) domain of mouse c-Crk protein negatively regulates tyrosine phosphorylation of the p130, and that lack of the SH3(2) domain in B-Crk and v-Crk may contribute, at least partly, to their morphological alteration or transforming ability through increasing tyrosine phosphorylation of the p130.
Amino Acid Sequence↗
Shear stress increases heparin-binding epidermal growth factor-like growth factor mRNA levels in human vascular endothelial cells.
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a recently identified potent vascular smooth muscle cell (SMC) mitogen. We investigated the effect of shear stress on human HB-EGF mRNA levels in cultured human umbilical vein endothelial cells (HUVEC). In response to shear stress (8 dyne/cm2), HB-EGF mRNA levels in HUVEC increased rapidly, peaked at 3 h, and returned to near base line at 7 h. The shear stress-induced HB-EGF gene expression in HUVEC is completely blocked by 12-O-tetra-decanoylphorbol-13-acetate pre-treatment, suggesting the induction of HB-EGF is mediated by protein kinase C.
Blotting, Northern↗
Expression of platelet-derived growth factor beta receptor on human monocyte-derived macrophages and effects of platelet-derived growth factor BB dimer on the cellular function.
Platelet-derived growth factor (PDGF) plays an important role in the process of atherosclerosis which is characterized by the presence of macrophage-derived foam cells. In the present study, the induction of the mRNA of PDGF-beta receptor was demonstrated during cell differentiation of human monocyte-macrophages, whereas no mRNA was detected in the cells during the early days of culture. Flow cytometry analysis using antibodies specific for PDGF-beta receptor and CD14 showed the presence of both PDGF-beta receptor and CD14 on human monocyte-derived macrophages, whereas no PDGF-beta receptor was detected on human monocytes 4 h after cell adhesion to a culture dish. In the binding assay of PDGF-BB on human monocyte-derived macrophages, a saturable and high affinity binding site with Kd of 27.5 pM and Bmax of 23.3 fmol/mg of cell protein was demonstrated. When human monocytes were cultured in the presence of the protein kinase C inhibitor staurosporine, PDGF-beta receptor induction was inhibited, and tetradecanoylphorbol acetate enhanced PDGF-beta receptor expression in human monocyte-derived macrophages, indicating that PDGF-beta receptor expression is associated with maturation and differentiation of monocyte-macrophages through the activation of protein kinase C. In response to PDGF-BB homodimer, PDGF-beta receptor was phosphorylated, and thymidine uptake and inositol trisphosphate production were stimulated in monocyte-derived macrophages. Furthermore, PDGF-BB suppressed the production of macrophages colony-stimulating factor in macrophages. The expression of PDGF-beta receptor on human monocyte-derived macrophages suggests that PDGF influences the process of atherosclerosis by regulating the function of macrophages as well as smooth muscle cells in the vascular wall.
Animals↗
Identification of homeobox genes expressed in human T-lymphocytes.
Homeobox genes encode transcription factors involved in the process of normal development and differentiation of cells and organs. Recently, some homeobox genes are found implicated in hemato-lymphoid neoplasms. To assess the role of homeobox genes in normal development and neoplastic transformation of T-cells, we have surveyed for homeobox-containing gene expression in a human T-cell leukemia line with a polymerase chain reaction. Ten members of homeobox genes were isolated, including one novel sequence. The novel sequence was most related to mouse Cdx. One of the others, HOXB7, is expressed in most malignant T-cell lines and CD4-positive peripheral blood T-cells. Together with the recent observations, these results suggest that the protein products of these genes may participate in normal functions and/or transformation of T-cells.
Amino Acid Sequence↗