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H Asou

Publications and source records attributed to H Asou.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mouse homolog of poliovirus receptor-related gene 2 product, mPRR2, mediates homophilic cell aggregation.

Poliovirus receptor (PVR) is a cell surface glycoprotein that belongs to the immunoglobulin superfamily. Although MPH was initially reported as the mouse homolog of human PVR, recent data strongly suggest that MPH is the mouse homolog of human PRR2, a PVR-related gene 2 product, and not that of human PVR. Thus MPH is renamed mPRR2 in this study. Physiological functions of the PVR-related gene products have not been elucidated, although PVR has been well characterized as the poliovirus receptor. In this study, a possible function of mPRR2 (MPH), which is not a functional receptor for poliovirus, was investigated. Mouse L cells expressing mPRR2 were prepared. Those mouse cells showed a higher activity of cell aggregation than the parental mouse L cells. Enhancement of cell aggregation was also observed for insect Sf9 cells infected with recombinant baculovirus carrying mPRR2 cDNA. On the other hand, L cells expressing human PVR or monkey PVR (AGM alpha1 or AGM alpha2) did not show increased cell aggregation. The cell aggregation activity of L cells expressing mPRR2 was inhibited by the addition of anti-mPRR2 monoclonal antibodies or a soluble mPRR2 molecule produced by the baculovirus expression system. An immunofluorescence study revealed that mPRR2 protein was localized to the cell-cell contact sites between cells expressing mPRR2. A similar localization of mPRR2 was observed for intrinsic mPRR2 molecules of the mouse neuroblastoma cell line NS20Y. The contact site-specific localization of mPRR2 was not observed on the border between mPRR2-expressing and nonexpressing HeLa cells. Furthermore, mPRR2 proteins directly bound to each other in vitro. mPRR2 was detected on various types of cultured cells of mouse origin and in various mouse tissues. These results suggest that mPRR2 is an intercellular adhesion molecule with a homophilic binding manner.

Animals↗
PubMed1997

Digital fluorescence imaging of elementary steps of neurosteroid synthesis in rat brain glial cells.

With fluorescence microscopic imaging, we have examined Ca2+ signaling, LDL uptake and distribution of cytochrome P450 scc on individual rat brain glial cells in order to investigate the molecular mechanisms of neurosteroid synthesis. Astrocytes and oligodendrocytes were cultured from newborn rat brain. Ca2+ signaling was observed in Calcium Green-1 loaded astrocytes upon neurotransmitter stimulations using video-enhanced microscopy. Upon stimulation of serotonin and glutamate, we observed typically three types of Ca2+ signaling which were Ca2+ oscillations, a transient increase in Ca2+ concentration and Ca2+ oscillations superimposed on a transient Ca2+ increase. On the other hand, histamine and ATP induced only a transient increase in Ca2+ without oscillatory response. Uptake of octadecyl rhodamine (R18) labeled LDL by astrocytes and oligodendrocytes was observed in the time scale of 30 min with confocal laser scanning microscopy. Some localization of LDL in the cytoplasm was observed for astrocytes. For oligodendrocytes, incorporated LDL was distributed over the entire cytoplasmic region of both cell body and multiple branched cell processes. The presence of a significant amount of cytochrome P450 scc was demonstrated with immunofluorescence staining in both astrocytes and oligodendrocytes. The density of P450 scc in both glial cells was suggested to be around 1% of that in bovine adrenocortical fasciculata cells. The results lead to an improved quantitative picture of neurosteroid synthesis in glial cells.

Adrenal Cortex↗
PubMed1996

Primary effusion lymphoma in women: report of two cases of Kaposi's sarcoma herpes virus-associated effusion-based lymphoma in human immunodeficiency virus-negative women.

Recent molecular evidence suggests an association with a new herpes virus, Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8), and primary effusion lymphomas (PEL). PELs have a characteristic morphology, phenotype, and clinical presentation with malignant effusions in the absence of a contiguous solid tumor mass. Most cases of PEL have occurred in human immunodeficiency virus (HIV)-positive male patients who are coinfected with Epstein-Barr virus (EBV). This report describes two cases of PEL in HIV- and EBV-negative women. In one patient, a pleural cavity PEL was preceded by classic Kaposi's Sarcoma (KS) of the lower extremities. In the second patient, PEL developed in an artificial cavity related to the capsule of a breast implant. Both cases had the characteristic morphologic appearance of high-grade anaplastic/B-cell immunoblastic lymphomas, with loss of B-cell differentiation antigens, clonal immunoglobulin heavy chain gene rearrangements, and expression of activation antigen CD30. Both cases were negative for EBV, herpes virus simplex, and cytomegalovirus (CMV). DNA extracted from both lymphomas and skin KS specimen showed KSHV sequences by molecular analysis. This report expands the spectrum of KSHV-associated disease to include PEL in HIV-negative women.

Aged↗
PubMed1996

Axonal growth-related cell surface molecule, neurin-1, involved in neuron-glia interaction.

We purified and characterized a novel axonal growth-related molecule, neurin-1, which is anchored to the surface membrane via a phosphatidylinositol (PI) linkage. This molecule was detected by a combination of phosphatidylinositol-specific phospholipase C (PI-PLC) treatment from detergent-soluble mouse brain membranes and subsequent Western blot analysis with monoclonal antibody (MAb 2A). Neurin-1 is immunologically distinct from other known axonal growth associated surface glycoproteins. In immunoblots of embryonic mouse brain membrane, the MAb 2A recognized a single band at approximately 68 kDa, and showed that neurin-1 is mainly associated with fiber-containing regions of developing embryonic mouse brain. Expression is immunohistochemically similar to that of cell adhesion molecule L1, but in comparison, neurin-1 appears somewhat later. Late in embryonic development, neurin-1 appeared to be more stage- and region-specific. Its precise localization at the neural cell surface membranes was confirmed by immuno-electron microscopy using labeled and cultured live nerve cells. Neurin-1 was found only on the surface of the axon and growth cone. Neurin-1, otherwise termed PI anchor protein, corresponds closely in function to the other PI-anchored cell adhesion molecules. Anti-neurin-1 antibody (MAb 2A), however, perturbs the axonal growth and neural cell migration from the astrocyte feeder layer cultures. These results suggest that neurin-1 is one of the important cell surface molecules mediated in the neuron and glial cell interaction.

Animals↗
PubMed1996

Establishment and characterization of a novel acute promyelocytic leukemia cell line (UF-1) with retinoic acid-resistant features.

All-trans retinoic acid (RA) induces complete remission in a high proportion of patients with acute promyelocytic leukemia (APL). Nevertheless, most of these patients develop RA resistance and relapse. The mechanisms of RA resistance by APL cells are still unclear. To understand the characteristics of human leukemia, human leukemic cell lines are useful tools for study. APL cells have a strikingly low proliferation potential in vitro; thus, only one APL cell line has been established. We developed a novel APL cell line (UF-1) from a patient clinically resistant to all-trans RA. Cell surface markers in the UF-1 cells were positive for CD7, CD13, CD33, and CD38. Cytogenetic analyses revealed additional abnormalities, 46XX, add(1)(q44), add(6)(q12), add(7)(q36), t(15;17) (q21;q21). Molecular analyses showed a PML/RAR alpha fusion transcript. Sequence analysis of the RAR alpha gene in RA-resistant HL-60 cells disclosed a point mutation in codon 411 (C to T substitution), whereas UF-1 cells showed the normal sequence. All-trans RA did not change morphological features of the cell, NBT reduction activity, or their expression of CD11b antigens as determined by FACS analysis except at 10(-6) mol/L. RA also did not alter the growth curve of the cells as determined by the MTT assay. These findings suggest that the UF-1 cell is the first permanent cell line with spontaneous RA-resistant APL cells. This RA-resistant APL cell line may be a useful model for molecular studies on the block of leukemic cell differentiation and as a means to investigate the mechanisms of RA resistance.

Adult↗
PubMed1996

Expression of CD44H in the cells of neural crest origin in peripheral nervous system.

We investigated the expression of the adhesion molecule CD44 in rat peripheral nervous system (PNS) at the protein and mRNA levels. Most migrating neural crest cells strongly expressed CD44, in contrast to the lack of expression in the neural tube. In dorsal root ganglion (DRG) and sciatic nerve, the distribution of CD44, neurofilament (NF) and S100 suggested the localization of CD44 on the membrane of Schwann cell and neurones and in extracellular matrix (ECM). The expression of CD44 was also confirmed on the membrane of cultured neurones and Schwann cells from DRG. mRNA coding for the haematopoietic form of CD44, CD44H, was detected in neural crest cells, DRG neurones and Schwann cells. These results show that CD44 may play some role in migration of neural crest cells and myelination in terms of adhesion between Schwann cells, axons and ECM.

Animals↗
PubMed1996

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) in primary effusion lymphoma: ultrastructural demonstration of herpesvirus in lymphoma cells.

Recent molecular evidence suggests an association with a new herpesvirus, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8), and primary effusion lymphomas (PELs). PELs have a characteristic morphology, phenotype, and clinical presentation, with malignant effusions in the absence of a contiguous solid tumor mass. We have established a cell line (KS-1) from a KSHV-positive human immunodeficiency virus (HIV)-negative patient with pleural cavity-based lymphoma that was passaged into triple-immunodeficient BNX mice. In contrast to cell lines from body cavity-based lymphomas derived from HIV-positive individuals that contain both KSHV and Epstein Barr viral genome, these cells contain only KSHV, allowing for uncontaminated virologic studies. Ultrastructural examination identified malignant cells with features of late differentiating B cells (immunoblasts). Cells with viral cytopathic effect contained typical 110-nm intranuclear herpesvirus nucleocapsids and complete cytoplasmic virions, confirming the association of PEL with KSHV.

Animals↗
PubMed1996

Hidden monosomy 7 in acute myeloid leukemia and myelodysplastic syndrome detected by interphase fluorescence in situ hybridization.

Fifty patients [25 acute myeloid leukemia (AML) and 25 myelodysplastic syndrome (MDS)], without monosomy 7 according to conventional cytogenetics, were re-examined by fluorescence in situ hybridization (FISH). Eleven (44.0%) patients with AML and nine (36.0%) with MDS showed hidden monosomy 7. Two samples who had both monosomy 7 and iso chromosome 17 were analyzed by dual color FISH to identify their clonal origin, and showed that these two abnormalities can occur together or independently. Only one of 16 MDS patients without monosomy 7 transformed into AML whereas four of eight MDS patients with the hidden monosomy 7 transformed into AML, suggesting patients with this abnormality are more likely to undergo transformation to AML.

Adult↗
PubMed1996

Cytogenetic and molecular genetic studies on Indian patients with chronic lymphocytic leukemia.

This is the first cytogenetic and molecular genetic study to find any specific genetic abnormalities in Indian patients with chronic lymphocytic leukemia (CLL). Cytogenetic studies on 18 patients indicated that their karyotypes were relatively simple and trisomy 12 was seen on karyotype evolution in one patient. Fluorescence in situ hybridization (FISH) revealed abnormal clones of trisomy 12 in nine cases and RB gene deletion in 14 of the 29 cases analyzed. Three patients had both clones. Immunoglobulin genes were rearranged in all the cases and TCR beta in none of the 18 cases Southern blotted. BCL-1 was rearranged in one case. No rearrangement of BCL-2 gene was seen in any case. Genetic changes in Indian CLL were more similar to Western CLL than to Japanese CLL, even though India is supposed to be a low incidence area. Therefore, factors (such as HLA and other genetic markers) other than these routine parameters must be studied to explain the low incidence of CLL in India.

Aged↗
PubMed1996

Establishment of a myeloid leukaemia cell line (Kasumi-4) with t(9;22;11)(q34;q11;q13), inv(3)(q21q26) and the EVI1 gene activation from a patient with chronic myelogenous leukaemia in blast crisis.

A novel human leukaemia cell line (Kasumi-4) was established from the peripheral blood of a 6-year-old girl suffering from chronic myelogenous leukaemia (CML) in blast crisis. The Kasumi-4 cells had the following characteristic features: undifferentiated blasts which were positive from CD34, CD33 and CD13 surface markers, but negative for myeloperoxidase platelet peroxidase, CD36, CD41 and CD42; chromosome abnormalities of t(9;22;11) (q34;q11;q13), inv(3)(q21q26); and elevated expression of EVI1 gene which is located at chromosome band 3q26. Megakaryocytic maturation was not observed in the liquid culture following the addition of TPA, IL3, IL-6 or GM-CSF, b2-a2 type of BCR-ABL chimaeric messenger RNA was detected by RT-PCR analysis. This the first leukaemia cell line with a three-way translocation containing the the Ph chromosome and the second cell line with an inv(3)(q21q26). This cell line appears to be useful for studying the mechanisms of leukaemogenesis involving these chromosomal abnormalities and related oncogenes.

Base Sequence↗
PubMed1996

A nonneuronal isoform of cell adhesion molecule L1: tissue-specific expression and functional analysis.

The cell adhesion molecule L1 is a multifunctional protein in the nervous system characterizing cell adhesion, migration, and neurite outgrowth. In addition to full-length L1, we found an alternatively spliced variant lacking both the KGHHV sequence in the extracellular part and the RSLE sequence in the cytoplasmic part of L1. This L1 variant was expressed exclusively in nonneuronal cells such as Schwann cells, astrocytes, and oligodendrocytes, in contrast to the expression of the full-length L1 in neurons and cells of neuronal origin. To investigate the functions of the L1 variant, we established cell lines transfected with a cytoplasmic short L1 (L1cs) cDNA that lacks only the 12-bp segment encoding for the RSLE sequence. The promoting activities of homophilic cell adhesion, neurite outgrowth, and neuronal cell migration of L1cs-transfected cells (L4-2) were similar to those of full-length L1-transfected cells (L3-1), but the cell migratory activity of L4-2 itself was clearly lower than that of L3-1. In conclusion, the short form of L1 is a nonneuronal type, in contrast to the neuronal type of the full-length L1. Deletion of the four amino acids RSLE in the cytoplasmic region of L1 markedly reduced cell migratory activity, suggesting an importance of the RSLE sequence for the signaling events of neuronal migration mediated by L1.

Amino Acid Sequence↗
PubMed1996

Establishment of an undifferentiated leukemia cell line (Kasumi-3) with t(3;7)(q27;q22) and activation of the EVI1 gene.

A novel human leukemia cell line (Kasumi-3) was established from the blast cells of a 57-year-old man suffering from myeloperoxidase-negative acute leukemia. The cell line had five distinctive features, as follows. 1) Flow cytometric analyses showed cell surface expression of CD7, CD4, CD13, CD33, CD34, HLA-DR and c-Kit. This phenotype is compatible with that of acute myelocytic leukemia cells with the M0 subtype in the French-American-British classification. 2) Kasumi-3 cells carried chromosomal abnormalities of t(3;7)(q27:q22), del(5)(q15), del(9)(q32), and add(12)(p11). The breakpoint of 3q27 was located near the EVI1 gene, and a high level of expression of the EVI1 gene was observed. 4) Kasumi-3 cells treated with TPA showed maturation to monocytic lineage. 5) Treatment with either interleukin (IL)-2, IL-3, IL-4, granulocyte-macrophage colony-stimulating or stem cell factor induced the proliferation of Kasumi-3 cells. Thus, the Kasumi-3 cell line shows the characteristic features of undifferentiated leukemia. It should, therefore, be useful both for studying the biological characteristics of acute myelogenous leukemia M0 subtype and for investigating the role of the EVI1 gene in leukemogenesis.

Acute Disease↗
PubMed1996

Cell-adhesion proteins of the immunoglobulin superfamily in the nervous system.

The unique groups of cell-adhesion proteins, such as IgSF, play essential parts in the formation and maintenance of the nervous system. Recent crystallographic studies have revealed a possible common structure of cell-adhesion proteins. The IgSF proteins are sub-grouped into simple, complex and mixed types. Accumulating evidence reveals the importance of cell-adhesion proteins in neural morphogenesis, maintenance and regeneration. They play key roles in neuronal migration, neurite outgrowth promotion, neurite fasciculation, pathfinding, target recognition, synaptogenesis and myelination. Mutations of cell-adhesion proteins result in neurological disease; for example, mutations of PO in hereditary neuropathy and mutations of L1 in hereditary hydrocephalus, MASA syndrome and spastic paraplegia type 1. Perspectives of the studies of neural cell-adhesion proteins are discussed.

Animals↗
PubMed1995

Decrease of NCAM expression and astrocyte-neurone interaction in long-term cultured astrocytes.

In order to assess the characteristics of the older astrocyte, we obtained long-term cultured rat astrocytes (20 months) and examined the features of protein expression in relation to neuronal interaction. In short-term cultured astrocytes, NCAM expressed strongly in contrast to weak expression of laminin by both immunocytochemical and ELISA assay. On the contrary, in long-term cultured astrocytes, a marked decrease of NCAM expression was observed along with increased laminin expression compared with short-term cultured astrocytes. The long-term cultured astrocytes remained positive to anti-GFAP antibody and showed a much lower ability to interact with neurones than the short-term cultured astrocytes. NCAM may be one of the responsible molecules related to the astrocyte-neurone interaction in the developing and ageing nervous system.

Animals↗
PubMed1995

Grafts of genetically modified fibroblasts expressing neural cell adhesion molecule L1 into transected spinal cord of adult rats.

L1, a neural cell adhesion molecule, is known to promote neurite elongation via a homophilic interaction in vitro. In the present study, fibroblast L cells that were genetically modified to express the L1 molecule were grafted to a lesion of rat spinal cord immediately after hemisection. Grafts drastically promoted regeneration of the axons in the injured spinal cord 2 weeks after grafting. A number of regenerating axons penetrated the glial scar along the host-graft interface, and elongated into the graft. These results suggest that grafts of genetically modified cells expressing L1 can provide an environment suitable for regeneration of the axons in the injured spinal cord.

Animals↗
PubMed1995

CNS myelinogenesis in vitro: time course and pattern of rat oligodendrocyte development.

Oligodendrocyte precursor cells that develop into myelin-forming cells of the central nervous system (CNS) were cultured from newborn rat brain to study how they proliferate and differentiate in normal conditioning medium, and their cell development was characterized by scanning electron microscopy (SEM) observation and immunocytochemical studies. We have identified A2B5-negative pre-O2A progenitor cells (so-called "type-1" oligodendrocytes) in the secondary cultures on the astrocyte feeder layer. These cells are very small (diameter: 3.5 microns), round, and glossy, and develop into the process-bearing O2A progenitor cells (called "type-2" oligodendrocytes), which also express myelin basic protein (MBP) both in the cell body and in their cell processes. Finally, they develop into mature oligodendrocytes (called "type-3" oligodendrocytes). After MBP expression is elicited in these cells and MBP accumulates in the cell process in the area in contact with the axon, these cells are capable of forming the myelin sheath. Therefore, we examined the mechanism of myelin-sheath formation of "type-3" oligodendrocytes using video time-lapse movies, and demonstrated that these cells initially sent out processes to search for axons several times before the onset of myelination. Then thick filopodia extended towards the axon, and at the same time, the axonal part of neuron moved forward. Finally the ruffling lamellipodial parts wrapped up the axon similarly to a transverse wave with the secured thick filopodial process on the axon acting as scaffolding. These results suggest that our experimental systems are useful in studying normal oligodendrocyte development and their cellular biochemistry, as well as investigating the mechanism of myelin formation by oligodendrocytes.

Animals↗
PubMed1995

Identification of two transcripts of AML1/ETO-fused gene in t(8;21) leukemic cells and expression of wild-type ETO gene in hematopoietic cells.

The t(8;21) is a common chromosomal abnormality, preferentially associated with acute leukemia showing features of myeloid differentiation. Recently, two genes--AML1, which has a unique runt domain, and ETO (MTG8)--have been isolated from the chromosomal breakpoint. In this study, we isolated and identified two fused transcripts from a leukemic cell line carrying t(8;21). AML1 and ETO were fused at the same position in these transcripts. One of the transcripts codes a unique domain, including two zinc finger domains and three proline- and one leucine-rich region. The other transcript codes only for one proline- and leucine-rich region but lacks zinc finger domains. We demonstrated by polymerase chain reaction (PCR) analysis that 1) these two transcripts are consistently expressed in leukemic cells with t(8;21) obtained from patients and 2) expression of AML1 was not restricted to the particular stage of hematopoietic differentiation but was present in all hematopoietic cells investigated. We also provide evidence that two wild types of ETO transcripts containing the region of the ETO gene in fused transcripts are expressed in hematopoietic cells from different lineages. The widespread expression of AML1 and ETO in hematopoietic cells suggests a fundamental role of these proteins in hematopoiesis. Furthermore, the differences in the carboxy termini of ETO may modulate the activity of fused proteins resulting from the chromosomal translocation t(8;21).

Acute Disease↗