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Biomedical subjects

K Kadomatsu

Publications and source records attributed to K Kadomatsu.

At least 73 records · Page 4Linked to original sources
PubMed1998

Disruption of the midkine gene (Mdk) resulted in altered expression of a calcium binding protein in the hippocampus of infant mice and their abnormal behaviour.

BACKGROUND: Midkine (MK) is a growth factor implicated in the development and repair of various tissues, especially neural tissues. However, its in vivo function has not been clarified. RESULTS: Knockout mice lacking the MK gene (Mdk) showed no gross abnormalities. We closely analysed postnatal brain development in Mdk(-/-) mice using calcium binding proteins as markers to distinguish neuronal subpopulations. Intense and prolonged calretinin expression was found in the dentate gyrus granule cell layer of the hippocampus of infant Mdk(-/-) mice. In infant Mdk(+/+) mice, calretinin expression in the granule cell layer was weaker, and had disappeared by 4 weeks after birth, when calretinin expression still persisted in Mdk(-/-) mice. Furthermore, 4 weeks after birth, Mdk(-/-) mice showed a deficit in their working memory, as revealed by a Y-maze test, and had an increased anxiety, as demonstrated by the elevated plus-maze test. CONCLUSION: Midkine plays an important role in the regulation of postnatal development of the hippocampus.

Animals↗
PubMed1998

Embigin/basigin subgroup of the immunoglobulin superfamily: different modes of expression during mouse embryogenesis and correlated expression with carbohydrate antigenic markers.

Embigin and basigin are highly glycosylated transmembrane glycoproteins with two immunoglobulin domains and form a subgroup in the immunoglobulin superfamily. Previous studies have demonstrated the functional significance of these molecules. In the present study, in situ hybridization analysis of their expression was performed during mouse embryogenesis. Embigin was strongly expressed in the endoderm during early postimplantation embryogenesis, and in the somite stage in the gut and visceral endoderm. Embryonic ectoderm and its derivative tissues weakly to moderately expressed this molecule. From day 10 to 15 of gestation, no embigin signal was detected. Basigin was more broadly expressed. During the organogenesis period, basigin was expressed in various epithelial tissues, brain ventricles, the spinal cord and dorsal root ganglion. The modes of expression of these two proteins throughout the egg cylinder stage correlated with the expression of the carbohydrate markers that they carry; embigin with Dolichos biflorus agglutinin binding sites and basigin with LeX antigen and more closely with fucosyltransferase IV, which forms the antigenic epitope. These findings imply that proteins with specific carbohydrate epitopes play roles in early postimpantation embryogenesis.

Animals↗
PubMed1998

Midkine expression in transient retinal ischemia in the rat.

PURPOSE: Midkine (MK), a 13-kDa heparin-binding growth factor, is known to exert neurotrophic activities on various nerve cells including retinal cells. To initiate studies toward determining the physiological role of endogenous MK, we investigated the spatial and temporal expression profile of MK before and after intraocular pressure-induced retinal ischemia. METHODS: Retinal ischemia was induced in Wistar strain rats by increasing the intraocular pressure to 110 mm Hg for 45 min via cannulation into the anterior chamber. The localization and abundance of the MK protein and mRNA were determined by the use of immunohistochemistry and in situ hybridization in the normal retina, as well as the retina after reperfusion. The protein expression profile was confirmed by Western blot analysis. RESULTS: Immunohistochemical analysis showed that MK protein was expressed in the ganglion cell layer, the inner portion of the inner nuclear layer, and in the retinal pigment epithelium of the normal rat. MK expression transiently decreased 3 h to 2 days after reperfusion, and then dramatically increased to a level higher than normal after 7 to 28 days. The temporal expression profile of the MK protein was confirmed by Western blot analysis. In situ hybridization analysis gave results comparable to those obtained with immunohistochemistry. CONCLUSIONS: MK was expressed in the neural cells of the retina in the normal state, but became more abundant after pressure-induced retinal ischemia. Thus, endogenous MK responds to ischemic treatment by an initial decrease in expression and then a period of expression above basal levels.

Animals↗
PubMed1998

Mouse chondroitin 6-sulfotransferase: molecular cloning, characterization and chromosomal mapping.

Chondroitin 6-sulfotransferase (C6ST) catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of the N-acetylgalactosamine residue of chondroitin. Using chick C6ST cDNA as a probe, we cloned the cDNA of mouse C6ST. The mouse enzyme was predicted to be composed of 472 amino acids, and exhibited 71% sequence identity with the chicken enzyme. The mouse and chicken catalytic domains exposed to the luminal side exhibited 81% identity, while the homology of the remaining regions was less. Transfection and expression of the mouse cDNA in COS-7 cells yielded C6ST activity. Keratan sulfate sulfotransferase activity, which was simultaneously expressed, amounted to 3% of the C6ST activity, this value being significantly lower than that observed in the case of the chicken enzyme. Mouse C6ST mRNA was strongly expressed in the spleen, lung, and eye. In situ hybridization revealed that the transcript was localized in stromal cells in the marginal zone and red pulp of the spleen, and stromal cells in the bone marrow. Fluorescence in situ hybridization analysis revealed the gene is located in mouse chromosome 9.

Amino Acid Sequence↗
PubMed1998

Midkine counteracts the activin signal in mesoderm induction and promotes neural formation.

Midkine (MK) is a heparin-binding growth factor that has been implicated in neural survival and differentiation, fibrinolysis, and carcinogenesis. It is expressed in the nervous system during early Xenopus development. In the present study, we demonstrated that injection of vegetal blastomeres with Xenopus MK at the 8-cell stage results in incomplete invagination. In the case of dorsal vegetal injection, hypertrophic neural tissue is produced. Animal caps isolated from embryos that have been injected with Xenopus MK and cultured with activin do not elongate, and all mesoderm markers examined, including both head and trunk/tail ones, are greatly diminished. In contrast, head-specific neural markers, XANF-1 and Xotx2, are induced, while trunk/tail neural markers, XlHbox6 and F-spondin, are decreased. Moreover, MK showes the same effects in animal caps injected with Xenopus Smad2 mRNA.

Activins↗
PubMed1998

Clusters of basic amino acids in midkine: roles in neurite-promoting activity and plasminogen activator-enhancing activity.

The removal of N-terminally located clusters of basic amino acids (N-tail) or C-terminally located clusters of basic amino acids (C-tail) from the midkine (MK) molecule severely reduced its neurite-promoting activity. However, experiments involving chemically synthesized MK derivatives revealed that the roles of the N-tail and C-tail were mostly indirect ones, i.e. they probably maintain the steric arrangements of the N-terminal and C-terminal halves. In particular, the C-domain, which is the C-terminal half devoid of the C-tail, retained considerable neurite-promoting activity when it was uniformly coated on a dish. The removal of the N-tail or C-tail also reduced the enhancing activity of plasminogen activator (PA) in aortic endothelial cells, although the effect was lower. There are two heparin-binding sites in the C-domain, Clusters I and II. A mutation in Cluster I [R78-->Q] affected the PA-enhancing activity only slightly, and a mutation in Cluster II [K83K84-->QQ] abolished the activity, while both mutations are known to reduce the neurite-promoting activity moderately. Therefore, the two heparin-binding sites in the C-domain play different roles in these two activities. Indeed, heparin exhibited different effects on these two activities. We also observed that intact MK was required for ordered neurite-promotion along the path of MK; one possible interpretation of this is that the N-terminal half is necessary for the stability of the molecule. Furthermore, K76 and K99 were found to be required for the secretion of MK; i.e. mutants in which one of these K residues was changed to Q were produced in the host cells, but not found in the medium.

Amino Acid Substitution↗
PubMed1998

Human N-acetylglucosamine-6-O-sulfotransferase involved in the biosynthesis of 6-sulfo sialyl Lewis X: molecular cloning, chromosomal mapping, and expression in various organs and tumor cells.

N-Acetylglucosamine-6-O-sulfotransferase catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of a non-reducing N-acetylglucosamine (GlcNAc) residue. We have cloned human GlcNAc-6-O-sulfotransferase cDNA, based on the sequence homology to cloned cDNA of mouse GlcNAc-6-O-sulfotransferase. The predicted protein sequence of the human enzyme was highly homologous to that of the mouse enzyme; in the 363 amino acid stretch of the catalytic region, the two proteins were nearly identical except for conservative changes in 3 amino acid residues. The expressed enzyme transferred sulfate to GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Gl cNAc. Co-transfection of the enzyme cDNA and fucosyltransferase VII cDNA into COS-7 cells resulted in cell surface expression of 6-sulfo sialyl Lewis X. Fluorescence in situ hybridization analysis revealed that the GlcNAc-6-O-sulfotransferase gene is located on human chromosome 7q31. mRNA of the human enzyme was strongly expressed in the bone marrow, peripheral blood leukocytes, spleen, brain, spinal cord, ovary, and placenta, and moderate levels of expression were observed in many organs including lymph nodes and thymus. In situ hybridization with the mouse system showed that the transcript was localized in specific regions of the brain, i.e. pyramidal cells in the CA3 subregion of the hippocampus, cerebellar nucleus and Purkinje cells. Among human tumor cells, strong expression of the mRNA was found in MOLT-4 and Jarkat lymphoblastic leukemia cells, Raji lymphoma cells, K-562 chronic myelogeneous leukemia cells, U251 glioma cells, and G361 melanoma cells. Carbohydrate structures synthesized by the sulfotransferase may be involved in various aspects of the differentiation and behavior of blood cells, their progenitor cells, and neurons in the central nervous system.

Amino Acid Sequence↗
PubMed1998

Stage-specific localization of basigin, a member of the immunoglobulin superfamily, during mouse spermatogenesis.

Ablation of the transmembrane glycoprotein basigin leads to azoospermic mice, indicating that this gene is essential for spermatogenesis. To examine the functions of basigin in the testis, the precise localization of basigin during spermatogenesis was examined immunohistochemically. In the adult mouse testis, basigin immunoreactivity appeared on the cell surface of leptotene spermatocytes and gradually increased in intensity during the meiotic prophase. Cytoplasmic staining, as well as cell surface staining, was detected in spermatids. The most conspicuous reactivity was found in the spermatids at steps 9-11 and in the flagella of spermatids. Immuno-electron microscopic analysis demonstrated that basigin was localized not only on the plasma membranes of spermatocytes and spermatids, but also on the plasma membrane of the Sertoli cell processes which contact the spermatocytes and spermatids. Basigin immunoreactivity was also detected during postnatal development in spermatocytes and spermatids but not in spermatogonia. Experimental cryptorchid testes which contain only spermatogonia and Sertoli cells in the seminiferous epithelium showed no basigin immunoreactivity. Seven days after surgical reversal of the cryptorchid testis, spermatocytes reappeared in the tubules, along with basigin immunoreactivity. Furthermore, in sterile mutant mice, in which neither spermatocytes nor spermatids were generated, no basigin immunoreactivity was detected in the seminiferous tubules. These findings indicate that expression of basigin is concomitant with appearance of spermatocytes in the seminiferous tubule, and suggest that basigin is involved in the interaction between Sertoli cells and germ cells at specific stages of spermatogenesis.

Animals↗
PubMed1997

Increased expression of midkine during the progression of human astrocytomas.

Midkine (MK), a member of a new family of neurotrophic and angiogenic growth factors whose expression is developmentally regulated, is produced in fetal astrocytes. Malignant astrocytomas, one of the most neovascularized tumors, are derived from astrocytes. There has been no investigation of the expression of MK in human astrocytic tumors. To determine if increased levels of MK expression correlate with the progression of human astrocytomas, we examined surgical specimens of astrocytic tumors of various grades using Northern and Western blotting. MK mRNA and protein expression levels were higher in high-grade astrocytomas (anaplastic astrocytomas and glioblastomas) than in low-grade astrocytomas. As shown by in situ hybridization, MK mRNA expression was intense in a majority of glioblastoma cells but was weak in a small number of low-grade astrocytoma cells. These findings suggest that MK expression correlates with the malignant progression of astrocytomas. The aberrant MK expression in high-grade astrocytomas may underlie their rapid growth and well-vascularized features.

Astrocytoma↗
PubMed1997

Abnormalities of sensory and memory functions in mice lacking Bsg gene.

Basigin is a highly glycosylated transmembrane protein belonging to the immunoglobulin superfamily. We used mutant mice lacking the basigin gene (Bsg) to investigate its involvement in learning and memory. Mutations were generated by the gene targeting method. Various kinds of learning and memory tasks were performed in mutant, hetero and wild type mice. The mutant mice showed worse performance than the wild and hetero mice in the Y-maze task, which assesses short-term memory, and in the water finding task, which examines latent learning, without any motor dysfunction. Moreover, the mutant mice showed less acclimation in the habituation task compared with the wild-type mice. The mutant mice were also more sensitive to electric foot-shock. These findings are consistent with the expression profile of basigin in the central nervous system. Thus, basigin may play an important role in learning and memory as well as in the sensory functions.

Animals↗
PubMed1997

Dimerization of midkine by tissue transglutaminase and its functional implication.

Midkine (MK), a retinoic acid-inducible growth/differentiation factor, serves as a substrate for tissue transglutaminase (Kojima, S. , Muramatsu, H., Amanuma, H., and Muramatsu, T. 1995. J. Biol. Chem. 270, 9590-9596). Upon incubation with transglutaminase MK forms multimers through cross-linkages. Here, we report the following results. 1) Heparin potentiated the multimer formation by MK. 2) The N- and C-terminal half domains each formed a dimer through the action of transglutaminase. 3) Gln42 or Gln44 in the N-terminal half and Gln95 in the C-terminal half served as amine acceptors in the cross-linking reaction, as judged from the incorporation of putrescine into whole MK or each half domain, and the competitive inhibition of the cross-linking by MK-derived peptides containing Gln residue(s). The strongest inhibition was obtained with Ala41-Pro51. 4) This peptide abolished the biological activity of MK to enhance the plasminogen activator activity in bovine aortic endothelial cells. The inhibition was limited against the MK monomer, and not seen against the MK dimer, separated by gel filtration chromatography. These results suggest that dimer formation through transglutaminase-mediated cross-linking is an important step as to the biological activity of MK.

Animals↗
PubMed1997

alpha-Galactosyl oligosaccharides conjugated with polyethylene glycol as potential inhibitors of hyperacute rejection upon xenotransplantation.

Antibodies to an alpha-galactosyl saccharide structure are mainly responsible for hyperacute rejection after pig-to-primate xenotransplantation. The beneficial effect of alpha-galactosyl oligosaccharides has been shown on the inhibition of anti-pig natural antibodies. We synthesized polyethylene glycol (PEG)-conjugates of alpha-galactosyl disaccharide (Di) and trisaccharide (Tri) as potential inhibitors of the rejection reaction. The half lives of Di, Tri, PEG-conjugated Di (Di-PEG) and PEG-conjugated Tri (Tri-PEG) were 18.1 +/- 2.3 min, 20.2 +/- 0.9 min, 38.7 +/- 2.8 min and 35.8 +/- 1.6 min, respectively. Furthermore, Di-PEG and Tri-PEG showed biphasic clearance, and their half lives at the second phase were longer than 10 hours. PEG-conjugated oligosaccharides (Di-PEG, Tri-PEG) markedly inhibited cytotoxic action of human sera to pig kidney cell line (PK15) compared to unconjugated oligosaccharides (Di, Tri). The binding of IgM antibodies to PK15 cells, however, was more strongly blocked by unconjugated oligosaccharides than PEG-conjugated oligosaccharides. This phenomenon can be explained by the finding that PEG has anti-complement activity and masks antigenic sites of oligosaccharides. In conclusion, conjugation of PEG to oligosaccharides provided two beneficial effects; prolonged intravascular retention time and anti-complement activity, upon systemic application of the oligosaccharides. The present findings opened a new approach to treatment of hyperacute rejection after xenotransplantation.

Animals↗
PubMed1997

Alteration of midkine expression associated with chemically-induced differentiation in human neuroblastoma cells.

Midkine (MK), a neurotrophic polypeptide of which expression is developmentally regulated in embryogenesis, is expressed in malignant tumor tissues including neuroblastoma (NB). A retinoic acid analogue, E5166, and dibutyryl cyclic AMP (dbcAMP) are known to induce differentiation in NB cells. This study showed that MK mRNA expression increased in association with differentiation by E5166, but not by dbcAMP in SK-N-SH and KP-N-RTBM1 human NB cell lines. We concluded that MK could be an important factor in differentiation of NB cells, and further, that there could be at least two pathways in differentiation of NB cells at molecular mechanism.

Antineoplastic Agents↗
PubMed1997

Expression of the retinoid-inducible polypeptide, midkine, in human epidermal keratinocytes.

Midkine (MK) is a retinoid-inducible and potent cell growth/differentiation factor active during mouse embryogenesis. We studied MK expression in various cell strains established from the skin. MK and its mRNA were detected in cultured keratinocytes but not in melanoma cell lines or dermal fibroblasts by both Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR). Treatment of cultured keratinocytes with retinoic acid (10(-5) M, 24 h) resulted in an increase in the level of MK mRNA. When added to cultured keratinocytes, MK stimulated cell proliferation fourfold. Immunohistochemistry revealed MK to be present at the epidermal-dermal junction in embryonic mouse skin and in normal human skin. The limited expression of MK in epidermal keratinocytes indicates that this polypeptide may be involved in the differentiation/proliferation of keratinocytes.

Animals↗
PubMed1997

Expression of midkine and pleiotropin in ovarian tumors.

OBJECTIVE: To compare the expression of midkine and pleiotropin in malignant ovarian tumors with that in normal and benign ovarian tissue. METHODS: Total RNA was isolated from 23 samples of normal ovaries, 15 benign ovarian tumors, and 36 malignant ovarian tumors. Midkine and pleiotropin gene expression was examined by using Northern blot analysis. To confirm the localization of midkine expression, in situ hybridization and immunohistochemical analyses were performed. The truncated midkine messenger RNA was examined using polymerase chain reaction with complementary DNA synthesized from total RNA with reverse transcriptase. RESULTS: Expression of midkine gene was observed in 19 of 23 normal ovary samples and in 51 of 53 ovarian tumors (13 of 15 benign, both of the two borderline tumors, and all 36 malignant tumors). Pleiotropin gene was expressed in six normal ovaries and in 24 tumors (nine benign, two borderline, and 13 malignant tumors). The expression of midkine in germ cell tumors was significantly lower than in epithelial tumors, whereas expression in malignant epithelial tumors was significantly higher than in benign ones. In germ cell tumors, two samples with differentiated neural tissues showed high levels of pleiotropin gene expression. In situ hybridization and immunohistochemical analysis showed strong expression of midkine in cancer cells. The truncated midkine messenger RNA was not found in any of the normal, benign, or malignant tissues examined. CONCLUSION: These results suggest an association between midkine and carcinogenesis. Expression of pleiotropin is more restricted, and high levels of its expression may be correlated with neural differentiation.

Adult↗
PubMed1997

Midkine induces the transformation of NIH3T3 cells.

Midkine (MK) is a heparin-binding growth factor and is frequently expressed at high levels in many human carcinomas. To investigate further the roles of MK in the regulation of cell growth, we introduced MK expression in NIH3T3 cells. A mixture of transfectants of an MK expression vector, but not a control vector, formed colonies in soft agar, showed an elevated cell number at confluence, and formed tumours in nude mice. An interesting characteristic of the transformed cells was that they became spontaneously detached from the culture dish substratum. In the transformed cells, MK was not only secreted, but also localized, in the perinuclear region as spots. The present data indicate that MK has the potential to transform NIH3T3 cells and suggest that overexpression of the MK gene may promote unregulated cell growth in vivo.

3T3 Cells↗