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Biomedical subjects

T Marunouchi

Publications and source records attributed to T Marunouchi.

At least 73 records · Page 4Linked to original sources
PubMed1990

Activation and proliferation of the isolated microglia by colony stimulating factor-1 and possible involvement of protein kinase C.

Microglia were isolated from primary mixed brain cell culture of normal newborn mice and then cultivated. They were able to be maintained in vitro for 1-2 months, but incorporated little [3H]thymidine under normal culture conditions. When treated with the conditioned medium of L929 mouse fibroblast cells as a crude CSF-1 (mouse macrophage-colony stimulating factor) or purified CSF-1, microglia showed morphological changes and increased in both cell number and [3H]thymidine uptake. In addition, crude CSF-1 increased lysosomal enzyme activity and superoxide anion formation of microglia up to 2 and 3.8 fold as control value, respectively. These effects of CSF-1 were not observed in the purified astrocyte culture. Purified microglia had CSF-1 receptors which were recognized by the anti-CSF-1 receptor antibody that arose from a peptide of a product of proto-oncogene, c-fms. 12-O-Tetradecanoylphorbol-13-acetate (TPA) also increased microglia cell number and their biochemical activities, suggesting the possible involvement of protein kinase C activation. Protein kinase inhibitors, such as staurosporine or H-7, inhibited the effects of both CSF-1 and TPA. These results indicate that microglia may be regulated in its biochemical and proliferation activities by CSF-1 and that this may occur via activation of protein kinase C.

Animals↗
PubMed1990

Effects of colony stimulating factors on isolated microglia in vitro.

Effects of colony stimulating factors (CSF), known regulators for cells in monocytic lineage, on isolated microglia were examined. Interleukin-3 (IL-3) induced only morphological changes in rod-shaped microglia, while granulocyte-macrophage CSF (GM-CSF) and CSF-1 induced both morphological changes and proliferation of microglia. CSF-1 also activated the enzyme activity of microglia. These observations indicated that, in terms of regulation by cytokines, microglia are similar to mature cells in monocytic lineage. Although astrocytes reportedly produce IL-3 and GM-CSF, the effects of astrocyte-conditioned medium (Ast-Sup) were different from those of either IL-3 or GM-CSF. Ast-Sup caused ameboid microglia to become ramified, and did not induce proliferation of microglia. Factors from astrocytes may have a role in the transformation of microglia which occurs in either normal developing brain or inflammation in the brain.

Animals↗
PubMed1990

Expression of protein kinase C isozyme in epidermal Langerhans cells of the mouse.

Protein kinase C (PKC) is encoded by a complex of a gene family, and its multiple isozymes are expressed in various mammalian tissues. We examined whether PKC is expressed in epidermal Langerhans cells (LC) of the mouse by using monoclonal antibodies specific to PKC I, PKC II, and PKC III isozymes (respective products of PKC genes gamma, beta, and alpha). Immunohistochemical and immunoblotting studies revealed that LC of adult C57BL/6 mice express PKC II, while PKC I and PKC III were not detected. In keratinocytes, none of the isozymes were detected. These results suggest that PKC II is a novel marker of LC and that it possibly plays a regulatory role in epidermal LC of the mouse in vivo.

Animals↗
PubMed1990

Isolation and culture of panning method-enriched Langerhans cells from dispase-dissociated epidermal cells of the mouse.

Langerhans cells (LCs) are bone marrow-derived, Ia-positive antigen-presenting cells in the epidermis which constitute 2-4% of the total epidermal cells. We examined the usefulness of a combination of dispase treatment and the panning method for enriching and culturing mouse LCs. Trunk skin was treated with partially purified dispase (Godo Shusei, type II) to separate epidermal sheets and to dissociate epidermal cells. Suspended cells were treated with ascites or culture supernatant containing anti-Ia monoclonal antibody, and LCs were enriched by the Ia-mediated panning method. Per mouse, 3-4 X 10(5) LCs were recovered with greater than 95% purity and greater than 90% viability. Enriched LCs potently stimulated the allogeneic mixed-leukocyte reaction. Ultrastructural observations revealed that enriched LCs contained many vesicles but almost no Birbeck granules. A laminal structure, which was apparently adhesive to the surface of LCs, was observed when ascites were employed as the anti-Ia antibody. These results indicate that a combination of dispase treatment and the Ia-mediated panning method is very useful for isolating high yields of functionally mature murine Langerhans cells with high purity and viability.

Animals↗
PubMed1990

Human T-cell leukemia virus type I trans activator induces class I major histocompatibility complex antigen expression in glial cells.

Transfection of the tax gene encoding the trans activator of human T-cell leukemia virus type I into glial line cells induced class I major histocompatibility complex (MHC) antigens on these cells. This occurred through the interaction of tax protein with the gene encoding class I MHC antigens but not through any soluble factors, such as interferons, or factors from glial cells. Since neural cells do not usually express MHC antigens, this novel mechanism may be an intermediate event between viral infection and subsequent immune-mediated pathology in the central nervous system.

Animals↗
PubMed1990

Expression of protein kinase C isozyme in human Langerhans' cells.

Protein kinase C is a key molecule controlling signal transduction into the cell. We recently reported that protein kinase C II isoenzyme, but neither I nor III isozyme, was expressed in epidermal Langerhans' cells of the adult mouse, and that none of these isozymes was detected in keratinocytes. In this study, we examined the expression of protein kinase C isozymes in human Langerhans' cells in vivo to see whether the expression of protein kinase C II isozyme in Langerhans' cells is a mouse-specific trait. Immunohistochemical studies revealed that protein kinase C II isozyme, but neither I nor III isozyme, was expressed in epidermal Langerhans' cells. None of these isozymes was detected in keratinocytes. These results suggest that the expression of protein kinase C II isozyme in epidermal Langerhans' cells in vivo is not a mouse-specific trait and that protein kinase C II isozyme is a novel phenotypic marker for epidermal Langerhans' cells in human as well as mouse skin.

Adolescent↗
PubMed1990

Induction of Langerhans' cell mitosis in vivo after orchiectomy on mice.

We recently reported that male mice have fewer Langerhans' cells (LCs) than females and that orchiectomy resulted in an increased LC density. In this study we demonstrate that orchiectomy induces a transient increase in the number of paired LCs (PLCs) before the increase in LC density occurs. The results of double staining for adenosine triphosphatase (ATPase) and 5-bromo-2'-deoxyuridine (BrdU) showed that all examined PLCs had incorporated the intraperitoneally injected BrdU, while only 0.7% of the unpaired LCs were BrdU-positive; that supported the notion of PLCs as being divided daughter LCs. Orchiectomy appears to induce a transient increase in mitotic activity of LCs resulting in the increased LC density.

Animals↗
PubMed1989

Production of tumor necrosis factor-alpha by microglia and astrocytes in culture.

Stimulation of mouse astrocytes and microglia in enriched culture by lipopolysaccharide (LPS) results in the production of a cytotoxic factor that is functionally similar to macrophage-derived tumor necrosis factor-alpha (TNF). This cytotoxic factor kills murine L929 cells, and is neutralized by a monoclonal anti-mouse TNF. The production of this factor is inhibited by pretreatment of cells by actinomycin D. Microglia are more sensitive to LPS and produce much higher activity of cytotoxicity in lower concentration of LPS than astrocytes. These results suggest that microglia are the major producers of TNF in the brain and may play a role in certain pathological conditions in the brain.

Animals↗
PubMed1989

Dose-dependent regulation of macrophage differentiation by mos mRNA in a human monocytic cell line.

The proto-oncogene c-mos was expressed during differentiation of the human monocytic cell line U937 into macrophages. To investigate a possible role of the mos oncogene, we introduced the v-mos gene under an inducible promoter, MT-I, into U937 cells. The v-mos transformed cells expressed mos mRNA at an amount proportional to the concentration of Zn2+ ions. The induction of the v-mos gene caused growth inhibition and macrophage differentiation in these cells. The differentiation of v-mos transformed monocytes into macrophages required continuous expression of the v-mos gene. The extent of expression of phenotypic characteristics of macrophages, such as phagocytosis, cell surface antigens and typical morphology, depends on the amount of mos mRNA present. We were therefore able to demonstrate that the expression of only one oncogene, mos, determines monocyte differentiation into macrophages.

Antigens, Surface↗
PubMed1989

Effect of systemic and topical application of testosterone propionate on the density of epidermal Langerhans cells in the mouse.

Epidermal Langerhans cells (LCs) are bone marrow-derived immune cells in the epidermis. Recently, we reported that adenosine triphosphatase (ATPase)-positive LC density in the hind-limb skin of male mice was lower than that of female and that orchiectomy resulted in an increase in LC density, though ovariectomy had no significant effect. To further investigate the control mechanisms of sex differences in LC density, the effect of systemic and topical application of testosterone propionate (TP) on LC density was examined in C57BL/6 mice. Subcutaneous injections of TP 5.8 X 10(-8) mol (20 micrograms)/day/mouse for 14 d resulted in a significant decrease in LC density both in orchiectomized males and normal females, and such an effect was also observed in adrenalectomized mice, suggesting that this effect of TP is not indirectly mediated by glucocorticosteroids. TP was also effective when applied as an ointment (1% or 5%) to the right hind-limb skin of both orchiectomized males and normal females for 14 d; namely, the LC density of the right hind-limb was lower than that of the left. Beta-estradiol and progesterone 5.8 X 10(-8) mol/day/mouse had no significant effect on LC density when systemically applied for 14 d to normal males and females. These results suggest that sex differences in LC density may result from higher concentrations of testosterone or its metabolites in males, and that the function of testosterone may be local.

Administration, Cutaneous↗
PubMed1987

Sex differences in the densities of epidermal Langerhans cells of the mouse.

Cutaneous immune reactions are known to show sexual dimorphism. Langerhans cells (LCs) are bone marrow-derived immune cells in the epidermis and are essential to immune reactions in the skin. In the present research, a study was made of the differences in LC density of male and female mice. Epidermal sheets were separated from the skin of the glabrous part of hind limbs and ears of specific pathogen-free (SPF) mice by ethylenediaminetetraacetic acid (EDTA) treatment and stained for adenosine triphosphatase (ATPase) activity. The density of LCs of hind limb epidermis in male C57BL/6 (823 +/- 20/mm2) and BALB/c (1689 +/- 66/mm2) mice was significantly less than that in females (1363 +/- 52/mm2, p less than 0.001; 2249 +/- 105/mm2, p less than 0.001, respectively). Langerhans cell density in the ears of male C57BL/6 (465 +/- 24/mm2) mice was also significantly less than that in females (542 +/- 17/mm2, p less than 0.02). Although ovariectomy failed to bring about any change in the LC density of hind limb epidermis in female C57BL/6 mice, the LC density in male C57BL/6 mice increased significantly at 4 weeks following orchiectomy (sham operation, 564 +/- 27/mm2; castration, 1179 +/- 49/mm2, p less than 0.001). These results indicate that mouse epidermal LC density depends on sex, i.e., male mice have fewer LCs than female mice. The reduction in LC density in males may possibly be caused by the testis.

Animals↗
PubMed1987

A factor inducing differentiation of the human monocytic cell line U-937 produced by 12-O-tetradecanoylphorbol 13-acetate-treated U-937.

A new factor capable of inducing differentiation of human leukemic cell line U-937 into macrophages was found and partially purified from the conditioned medium of U-937 previously treated with 12-O-tetradecanoylphorbol 13-acetate. The purification procedure included ultrafiltration, DEAE-Sephacel and butyl-Toyopearl column chromatography. The purified factor gave a major band of protein with a molecular weight of 67,000 daltons which coincided with the biological activity of differentiation-inducing factor, and it was not adsorbed on a concanavalin A column. These results suggest that this factor is distinct from other differentiation-inducing factors.

Cell Differentiation↗
PubMed1983

Decrease in uH2A (protein A24) of a mouse temperature-sensitive mutant.

ts85 cell is a temperature-sensitive mutant of cell cycle, and chromosomal protein uH2A of this mutant disappears at the non-permissive temperature. uH2A in nucleosomes is thought to be synthesized or degradated as follows. H2A + Ubiquitin in equilibrium uH2A. Up to date, the degradation of uH2A was shown to be catalyzed by uH2A lyase, however no enzymes (factors) concerning its synthesis have been elucidated. Here, we show that ATP is prerequisite for the synthesis of uH2A, and that the disappearance of uH2A at the non-permissive temperature may be due to a reduction in the rate of synthesis rather than an increase in the rate of its degradation.

2,4-Dinitrophenol↗
PubMed1981

A mouse temperature-sensitive mutant defective in H1 histone phosphorylation is defective in deoxyribonucleic acid synthesis and chromosome condensation.

By means of a temperature-sensitive mutant (ts85 strain), we have studied the effect of the decrease in H1 histone phosphorylation on DNA synthesis and chromosome condensation. When ts85 cells were incubated at 39 degrees C (nonpermissive temperature), the rate of H1 histone phosphorylation was decreased gradually and reached half that at 33 degrees C (permissive temperature) by 6-h incubation. Wild-type cells, growth-revertant ts85 cells (ts85R-MN3), and other ts mutants which were arrested mainly at the G2 phase at 39 degrees C had no defects in H1 histone phosphorylation. When ts85 cells were synchronized at the G1/S boundary at 33 degrees C and released from the blockade at 39 degrees C, approximately 70% of cells passed through the S phase and stopped at the G2 phase. The rest were distributed in G1/S to the S phase and mitotic cells were not detected at all. When ts85 cells, synchronized at the G1/S boundary, were further incubated for 8 h at 39 degrees C with a synchronizing agent, the rate of phosphorylation of H1 histone was decreased and the cells were not able to complete DNA synthesis after release from the blockade. Cytofluorometric analysis revealed that the cells had DNA contents of the S phase. Taken together with our earlier data [Matsumoto, Y., Yasuda, H., Mita, S., Marunouchi, T., & Yamada, M. (1980) Nature (London) 184, 181-183], both events, incomplete DNA replication and a defect in chromosome condensation, were thought to be ascribed to the decrease in H1 histone phosphorylation.

Animals↗
PubMed1978

A temperature-sensitive mutant showing two defective functions.

A temperature sensitive growth mutant, 13B11 derived from CHO-K1 has been partially characterized. Upon shift to the nonpermissive temperature (39 degrees C) DNA synthesis slows down, but it is partly resumed after prolonged incubation at 39 degrees C. The radioautographic results suggest that reduction in the rate of DNA synthesis is mainly due to decrease in the proportion of DNA synthesizing cells and that increase in that rate observed afterwards is due to appearance of cells that enter S. Synchronized mutant cells incubated at 39 degrees C from the beginning of G1 enter S with the delay of 6 hours. By incubating the cells at 39 degrees C for a restricted period during the G1 phase, some processes in late G1 are found to be susceptible to the high temperature. Mutant cells shifted up in the middle of S performed cell division whereas cells up-shifted in G1 phase did not, although about a half of these cells divided when they were shifted down in the presence of hydroxyurea. The analysis of DNA content of the cells cultured at 39 degrees C for more than one generation time, revealed the accumulation of nuclei containing DNA in amount of almost 4C level. Accordingly in this mutant the process necessary for cell division is also temperature sensitive. Considering the frequency of the appearance of spontaneous revertants (2 X 10(16)), the apparent two lesions of this mutant might be ascribed to the single mutation.

Animals↗