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M Kusakabe

Publications and source records attributed to M Kusakabe.

At least 55 records · Page 3Linked to original sources
PubMed1998

Three-dimensional analysis of the developing pituitary gland in the mouse.

Prenatal development of the mouse pituitary gland was analyzed in three-dimensions by using confocal laser-scanning microscopy. In any wholemount preparation of the fetal pituitary gland from day 10 to day 18, immunofluorescence of laminin was observed in the deeper regions of the organ and demarcated the boundary of the epithelial tissue from the surrounding mesenchyme. Three-dimensional capillary networks in the fetal pituitary gland at day 13, day 15, and day 18 were visualized clearly by perfusing the blood vessels with an fluorescein isothiocyanate-labelled gelatin solution. During days 12-14, cellular plates protruded from the anterior wall of the pituitary anlage and extended toward the base of the infundibulum. At the same time, the mesenchyme situated among the cellular plates separated from the surrounding mesenchyme except at the anteroventral portion of the anlage. In a posterior wall of the anlage, intercellular depositions of laminin were found among the epithelial cells, some of which reached the laminin sheet in the basement membrane of the anlage. From days 15-18, the pituitary gland enlarged, and the mesenchyme spread radially from the median anteroventral portion to the lateral, posterior, and dorsal regions and finally expanded throughout the entire organ. At the periphery, the mesenchyme in the pituitary gland connected with that surrounding the capsule. Laminin was still found in the intercellular spaces between the epithelial cells, and most of the intercellular depositions of laminin were combined with the laminin sheet in the epithelial basement membrane. An abundance of vessels entered the organ from its anteroventral portion, spread, and connected with one another throughout the gland, similar to the distribution of mesenchyme. Intercellular laminin would induce the polarization of the contacting epithelial cells, resulting in rearrangement of the epithelial cells. The mesenchyme might spread in the pituitary gland, providing the intercellular laminin a foothold, in order to cleave the epithelial cell mass into lobules. The development of capillary nets in the adenohypophysis corresponded well with that of the mesenchyme. Because laminin localizes mainly in the basement membrane in the fetal organs, immunostaining of laminin clearly indicates the boundary between epithelial tissue and the mesenchyme. Three-dimensional observation of laminin in wholemount preparation is very useful for studying morphogenesis.

Animals↗
PubMed1998

Simultaneous observation of capillary nets and tenascin in intestinal villi.

BACKGROUND: In order to reveal the biological role of capillaries in a tissue, it is desirable to study the three-dimensional distribution of capillary nets in relation to tissue architecture. However, the simultaneous observation of the three-dimensional distribution of these nets and other substances has been rarely performed to date. In the present study, we have developed a novel method for investigating the three-dimensional distribution of capillary nets simultaneously with that of extracellular matrix components, such as tenascin, using the confocal laser scanning microscope. METHODS: Adult male mice were perfused with TRITC-labelled gelatin. After perfusion, the intestine was irrigated with chilled fixative containing paraformaldehyde and picric acid, dissected, and returned to the same fixative. The intestine was further sectioned and indirectly immunostained for tenascin using an FITC-labelled antibody. RESULTS: The three-dimensional distribution of capillary nets and tenascin in villi was simultaneously observed on stereo pairs of pseudo-colored and superimposed images. Tenascin was distributed at the basement membrane zone and in the underlying connective tissue but absent in some regions where capillary nets were running just beneath the epithelium. Substances other than tenascin also can be examined in correlation with capillary nets. CONCLUSIONS: This method will be useful for investigating the biological role of capillary nets.

Animals↗
PubMed1998

Reduced mRNA expression of neuropeptide Y in the limbic system of tenascin gene disrupted mouse brain.

Tenascin-C (TN), an extracellular matrix glycoprotein which reveals both neurite outgrowth-promoting and growth-inhibiting effects, is generated in the central nervous system. A previous study reported that TN-gene null mutant mice display hyperlocomotion and do not easily habituate to unfamiliar environments. Additionally, these mice display poor appetite, abnormal circadian rhythm and low pregnancy rate. The present study demonstrated that neuropeptide Y (NPY) mRNA expression is reduced in the limbic area of the TN gene-deficient mouse brain as compared to wild-type mice. NPY has been shown to affect emotion, circadian rhythm and food intake, and the present results suggest that the some behavioural abnormalities exhibited by TN-mutant mice may be in part due to the low level of expression of NPY mRNA in the limbic system.

Animals↗
PubMed1998

The effects of central administration of neuropeptide Y on behavior of tenascin-gene knockout mice.

Tenascin-C (TN), an extracellular matrix glycoprotein, plays a pivotal role in the regulation of neuronal pattern formation. TN-gene deficient mice produced by homologous recombination show hyperlocomotive activities. We have recently demonstrated that neuropeptide Y (NPY) mRNA expression is reduced in the limbic area of the TN-gene knockout mouse brain, compared to that in wild-type mice. We now report the effect of NPY on the behavior of TN mutant mice. Intracerebroventricular injection of NPY transiently decreased the hyperlocomotion of TN mutant mice. Concurrently, mice given NPY showed anxiolytic behavioral change as assessed by an exploratory model. The results presented here suggest that the hyperlocomotion of TN mutant mice is partially derived from severe tensity.

Animals↗
PubMed1998

In vivo electrophysiological distinction of histochemically-identified cholinergic neurons using extracellular recording and labelling in rat laterodorsal tegmental nucleus.

From indirect evidence we have proposed that cholinergic versus non-cholinergic neurons in the laterodorsal tegmental nucleus can be distinguished with the duration of their extracellularly recorded action potentials, "broad" spikes for the former, "brief" for the latter. To test this assumption more directly, we labelled single neurons recorded extracellularly in and around the laterodorsal tegmental nucleus with biocytin or neurobiotin, and processed the sections with reduced nicotinamide adenine dinucleotide phosphate-diaphorase, a proven marker for cholinergic neurons in the laterodorsal tegmental nucleus. Biocytin or neurobiotin which was deposited at the site of recording was incorporated into single neurons. Among 171 trials (91 for broad-spike and 80 for brief-spike neurons), marking was successful in 68 cases (29 for broad-spike and 39 for brief-spike neurons). Almost all (21/22) of the broad-spike neurons located within the laterodorsal tegmental nucleus were positive for reduced nicotinamide adenine dinucleotide phosphate-diaphorase staining, i.e. they were cholinergic, while all of the brief-spike neurons in and outside of the laterodorsal tegmental nucleus lacked the diaphorase activity, and were thus non-cholinergic. The present study shows that, after extracellular labelling of single neurons by biocytin or neurobiotin, cholinergic neurons in the laterodorsal tegmental nucleus are confidently distinguished from non-cholinergic ones in the corresponding area with their spike shapes. It is also shown that the cholinergic neurons distinguished by this criterion are characterized by their tonic firing at slightly lower rate and larger cell size than the brief-spike non-cholinergic ones.

Action Potentials↗
PubMed1998

Effect of tenascin-C deficiency on chemically induced dermatitis in the mouse.

Tenascin-C is a large extracellular matrix glycoprotein characterized by its spatiotemporal expression during embryogenesis, carcinogenesis, and wound healing. Many in vitro studies on tenascin-C have revealed its multifunctional properties; however, disruption of the tenascin-C gene did not reveal any obvious abnormalities during development, and its function in vivo remains unclear. Here, we investigated whether tenascin-C is involved in inflammatory dermatitis in adults by studying chemically induced dermatitis in tenascin-C knockout mice. An epicutaneous application of a hapten, 2,4-dinitrofluorobenzene, to the ear skin of BALB/CA mice resulted in inflammation and induced the expression of tenascin-C. In congenic tenascin-C knockout mice, the dermatitis occurred more severely than in wild-type mice; infiltration of polymorphonuclear cells in knockout mice persisted longer than in wild-type mice, and the elastosis-like disorganized extracellular matrix was also seen in the ear. These results suggest that tenascin-C plays a role in vivo in inflammatory responses in the skin, and that the genetic background has profound effects on the function of tenascin-C in mouse dermatitis.

Animals↗
PubMed1998

Embryoglycan ectodomains regulate biological activity of FGF-2 to embryonic stem cells.

Basic fibroblast growth factor (FGF-2) functions as a natural inducer of mesoderm, regulator of cell differentiation and autocrine modulator of cell growth and transformation. The FGF-2 signals are transduced through receptors with intrinsic protein tyrosine kinase activity. However, receptor binding and activation is governed by extracellular matrix, cell surface or soluble proteoglycans. This paper focuses on the role of proteoglycans synthesized by embryonic cells, embryoglycans, in FGF-2 signaling via FGF receptor-1 (FGFR-1). We found that embryoglycan ectodomain Lewis X, analog of developmentally regulated embryonic cell surface epitope TEC 1, promotes oligomerization of FGF-2 in the cell free chemical crosslinking. In vitro assays show that a large molar excess of extracellular Lewis X does not inhibit binding of FGF-2 to embryonic stem (ES) cells, but prevents the mitogenic effect of FGF-2. Western blot analysis of ES cells revealed the presence of abundant 52 kDa and trace amounts of 67 and 125 kDa isoforms of FGFR-1. However, none of these isoforms undergo any detectable changes in tyrosine phosphorylation under the conditions that modulate the mitogenic effect of FGF-2. Rather, a primary substrate of all receptor tyrosine kinases, phospholipase C gamma (PLC gamma), is activated by both FGF-2 and Lewis X. The combination, FGF-2 plus Lewis X, leads to weak inhibition, when compared with the effects of FGF-2 and Lewis X, respectively. In accordance, the level of phosphorylation of non-receptor tyrosine kinase c-Src is reduced in a reversed pattern to PLC(gamma). Furthermore, in this particular cell type we show the presence of activated forms of extracellular signal-related kinase (ERK) in all nontreated and treated cells. These findings demonstrate that embryoglycan ectodomains may act as negative regulators of FGF-2-induced ES cell proliferation, most likely through the FGFR-1-independent signaling pathway.

Animals↗
PubMed1998

Tenascin takes part in the progress of pathological severity in cerebral falciparum infection.

We examined plasma level of circulating form of tenascin (TC) in falciparum malaria patients, cerebral malaria and non cerebral malaria, and compared them to uninfected healthy persons. Plasma level of TC examined were significantly higher in malaria patients than in control persons (p< 0.01). The results also show that among malaria patients, TC level was higher in the cerebral malaria patients compare to non cerebral malaria patients (p<0.10). Kinetics of TC level in plasma were related to kinetics of TNF-alpha level. Moreover, patients with higher level of TC showed higher level of parasitized erythrocytes binding ratio. Immunohistochemical study showed that TC was found in the cerebral microvessels of postmortem cerebral tissues from nine cerebral malaria cases. These results provide evidence that plasma level of TC correlates with the severity in cerebral malaria patients.

Brain↗
PubMed1998

Tenascin-C promotes healing of Habu-snake venom-induced glomerulonephritis: studies in knockout congenic mice and in culture.

Mice without the gene for tenascin-C, a multifunctional extracellular matrix protein expressed in many important biological events, including wound healing, did not show any phenotype. However, it is now obvious that the phenotype of deletion of one gene frequently depends on the genetic background. Therefore, we have newly generated tenascin-C knockout mice (KO) by backcrossing original KO into three congenic lines: C57BL/6N, BALB/cA, and GRS/A (GR). And we investigated the disease course of reversible kidney injury, Habu-snake venom-induced proliferative glomerulonephritis. In all strains, the disease was more severe in KO, but the severity varied with the strain. The KO-GR showed irreversibility; all treated KO-GR died by the 4th month due to renal failure. The diseased KO-GR showed abnormal regenerative reactions, including reduced proliferation of mesangial cells, key players in glomerulonephritis, and reduced production of some kinds of cytokines and matrices, leading to poor formation of granulation tissue. In culture, the mesangial cells from the KO-GR had the same potential for proliferation and response to cytokines as controls, but interestingly, to achieve this potential, they required contact with tenascin-C. These reactions were blocked by an anti-tenascin monoclonal antibody. The results of the present study, the first report showing the most dramatic phenotype so far discovered, have strongly suggested the importance of tenascin-C in the resolution of the renal inflammation and that of the genetic background on which the KO was developed.

Animals↗
PubMed1998

Cerebellar histogenesis as seen in identified cells of normal-reeler mouse chimeras.

The potential contribution of cell-cell interactions and extracellular factors to cytoarchitectonic abnormalities in the cerebellum of the reeler mutant mouse was investigated by forming chimeras between the reeler and normal animals. The strain origin of Purkinje cells, granule cells and Golgi epithelial cells was immunohistologically identified with a strain-specific antibody. We analyzed 16 overt coat color chimeras, 10 reeler <--> C3H and 6 reeler <--> Balb/c. Abnormal behavioral traits of reeler were rescued in all chimeras. However, cerebellar histology was more affected in reeler <--> C3H chimeras than in reeler <--> Balb/c. Purkinje cells from the normal genotype occupy ectopic positions, and reeler genotype cells are arranged appropriately in the same chimeric cerebellum. We also obtained histologically normal chimeras with a significantly high contribution of the reeler genotype in Purkinje cells, Golgi epithelial cells and granule cells. These results clearly indicate that the abnormal cell positioning and cytoarchitecture of neurons and glia in the reeler is caused by a deficiency of extracellular environments, but is not determined cell-autonomously. The present data on chimeric mice suggest that Reelin is one of the important extracellular environmental factors that affects indirectly radial glial cells during cerebellar histogenesis.

Animals↗
PubMed1997

Effects of cholecystokinin-B receptor antagonist on dopamine system in tenascin mutant mice.

The aim of this study was to investigate the effect of cholecystokinin (CCK) receptor antagonist on the abnormal behavior and dopamine (DA) transmission of tenascin (TN)-gene knockout mice. Recently, we demonstrated that TN-gene deficient mice show hyperlocomotion that is related to reduced DA transmission and tyrosine hydroxylase (TH) activities in the brain. In this report, we show that the intraperitoneal administration of a CCK-B receptor antagonist, PD135158 (0.1 mg/kg), but not a CCK-A receptor antagonist, lorglumide, inhibited hyperlocomotion. Moreover, PD135158 reversed the low levels of DA turnover rate and TH activities in the striatum of TN-gene knockout mouse brain. These results suggest that CCK-B receptor is involved in the behavior of TN-gene knockout mouse through striatal DA transmission.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1997

Paradoxical behavioral response to apomorphine in tenascin-gene knockout mouse.

Tenascin is a large extracellular matrix glycoprotein which is highly expressed in the developing nervous system. To examine the role of tenascin in vivo, we have produced mice in which the tenascin-gene is inactivated. These animals did not easily habituate to unfamiliar circumstances and displayed hyperlocomotion. A dopamine receptor agonist, apomorphine, reduced this hyperlocomotion dose dependently, but this phenomenon was not due to the appearance of apomorphine-induced stereotypic behavior, suggesting that tenascin-gene mutant mice have a paradoxical behavioral response to apomorphine compared to wild-type mice.

Animals↗
PubMed1997

An oocyte-specific methylation imprint center in the mouse U2afbp-rs/U2af1-rs1 gene marks the establishment of allele-specific methylation during preimplantation development.

An oocyte-specific methylation imprint mark region, consisting of approximately 200 bp from the mouse imprinted gene U2afbp-rs, was identified within an area containing a CpG island and a short tandem repeat sequence. The oocyte-specific methylation was preserved in fertilized eggs and then expanded on the repressed maternal allele during preimplantation development until the adult methylation pattern was achieved by 12.5 days of embryonic development. These results indicate that the oocyte-specific imprinting mark region acts as a center in establishing the hypermethylated region on the repressed maternal allele. Furthermore, a region that is hypermethylated in both gametes was identified but its hypermethylation was conserved only on the maternal allele during preimplantation development, suggesting that some factor(s) inherited from oocytes may act to maintain hypermethylation on the maternal allele.

Alleles↗
PubMed1997

Tyrosine hydroxylase activity and its mRNA level in dopaminergic neurons of tenascin gene knockout mouse.

We have recently demonstrated that some tenascin (TN) gene-knockout mice display abnormal behaviors, and that these abnormal behaviors stem from a low level of dopamine transmission in the brain. In the present study, we elucidated that tyrosine hydroxylase (TH) activity in the frontal cortex, striatum, and hippocampus of TN-knockout mice which showed abnormal behavior was significantly decreased. Also, the TH mRNA level of the midbrain was decreased by 43% in these animals compared with values for wild-type mice. These results suggest that the low dopamine turnover rate in some areas of the brain of TN-knockout mice accompanied by motor defects is due, at least in part, to the reduction in TH activity caused by diminished TH mRNA expression, and that TN-knockout mice exhibit abnormal behaviors in the presence of low levels of TH-gene expression.

Animals↗
PubMed1997

Tenascin-C knockout mouse has no detectable tenascin-C protein.

A recent study by Mitrovic and Schachner (J Neurosci Res 42:710-717, 1995) reported the detection of a small amount of truncated tensacin-C (TN-C) in the nervous system of the TN-C knockout mice created by Saga et al. (Genes Dev 6:1821-1831, 1992). The authors suggested that the truncated protein might be responsible for the failure to detect any phenotypic abnormalities in the knockout mice. We have reexamined the knockout mice in our laboratories by Western blot and immunocytochemistry, and have not detected any full-length or truncated TN-C protein. In addition, we note that the construction of the knockout gene deleted the signal sequence, so if any residual truncated protein were produced it would be trapped in the cytoplasm, and therefore inaccessible to extracellular ligands or receptors. We therefore conclude that the TN-C knockout created by Saga et al. is a valid TN-C null.

Animals↗
PubMed1997

The change in tenascin expression in mouse uterus during early pregnancy.

PURPOSE: Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring. METHODS: Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through Day 5 were analyzed. RESULTS: Immunoreactive TN and TN mRNA were expressed in the basement membrane of the epithelium as well as in the smooth muscle layer, and their distribution shifted from the subbasement region on Day 0-3 to the smooth muscle layer on Days 4 and 5. CONCLUSIONS: These results indicate that TN expression in the uterus during early pregnancy is spatiotemporally different and may be regulated by a different mechanism.

Animals↗