Biomedical subjects

M Kusakabe

Publications and source records attributed to M Kusakabe.

At least 91 records · Page 5Linked to original sources

PubMed1995

The reeler gene encodes a protein with an EGF-like motif expressed by pioneer neurons.

We have identified a strong candidate cDNA for the mouse reeler gene. This 5 kb transcript encodes a 99.4 kD protein consisting of 881 amino acids and possessing two EGF-like motifs. We assayed two independent mutant alleles--'Jackson reeler', which has a deletion of the entire gene, and 'Orleans reeler' which exhibits a 220 bp deletion in the open reading frame, including the second EGF-like motif and resulting in a frame shift. In situ hybridization reveals that the transcript is detected exclusively in the pioneer neurons which guide neuronal cell migration along the radial array. Our findings offer an explanation for how the reeler mutant phenotype causes a disturbance of the complex architecture of the neuronal network.

Amino Acid Sequence↗

PubMed1995

Development of a new apparatus to observe microcirculation chronically in continuous flow blood pump research.

To observe microcirculation chronically is an important key to the successful evaluation of the continuous flow blood pump. In this study, we succeeded in developing a new apparatus by which microcirculation could be observed chronically without a microscope in a conscious animal. The apparatus utilizes a charge coupled device (CCD). A thin living tissue, such as mesentery, is put directly on a highly integrated CCD and is lit up through the tissue with a light-emitting diode (LED). The vascular nets in the tissue are projected onto the CCD like a contact photograph, which is then sent to a television screen and which can be used to analyze their motion and function. A 0.5-inch CCD having 250,000 pixels was used in this study. The cover glass of the CCD was removed, and a fiber optic plate was fixed onto the surface of the CCD for the tissue to be able to contact with the apparatus surface without clearance. The CCD as well as the LED were molded with epoxy resin for electrical insulation. The apparatus was 35 mm wide and 12 mm high with a micro stand for an LED, which can be easily implanted into an animal. The apparatus was implanted into a rabbit for 12 h. The configuration of arterioles and venules, tens of micrometers in diameter, and their motions in subcutaneous tissue could be observed.

Animals↗

PubMed1995

Tenascin knockout mice: barrels, boundary molecules, and glial scars.

In light of a previous report suggesting that the brains of tenascin-deficient animals are grossly normal, we have studied the somatosensory cortical barrel field and injured cerebral cortex in postnatal homozygous tenascin knockout, heterozygote, and normal wild-type mice. Nissl staining, cytochrome oxidase, and Dil axonal tracing of thalamocortical axonal projections to the somatosensory cortex, all reveal the formation of normal barrels in the first postnatal week in homozygous knockout mice that cannot be distinguished from heterozygote or normal wild-type barrels. In addition to confirming the absence of tenascin in knockout animals, and reporting apparently reduced levels of the glycoprotein in barrel boundaries of heterozygote animals using well-characterized antibodies and immunocytochemistry, we also studied the DSD-1-PG proteoglycan, another developmentally regulated molecule known to be associated with transient glial/glycoconjugate boundaries that surround developing barrels; DSD-1-PG was also found to be expressed in barrel boundaries in apparently normal time frames in tenascin knockout mice. Peanut agglutinin (PNA) binding of galactosyl-containing glycoconjugates also revealed barrel boundaries in all three genotypes. We also examined the expression of tenascin-R, a paralog of tenascin-C (referred to here simply as tenascin). As previously reported, tenascin-R is prominently expressed in subcortical white matter, and we found it was not expressed in the barrel boundaries in any of the genotypes. Thus, the absence of tenascin does not result in a compensatory expression of tenascin-R in the barrel boundaries. Finally, we studied wounds of the cerebral cortex in the late postnatal mouse. The astroglial scar formed, for the most part, in the same time course and spatial distribution in the wild-type and tenascin knockout mice. However, there may be some differences in the extent of gliosis between the knockout and the wild type that warrant further study. Roles for boundary molecules like tenascin during brain pattern formation and injury are reconsidered in light of these findings on barrel development and cortical lesions in tenascin-deficient mice.

Animals↗

PubMed1995

Expression of paternal and maternal mitochondrial HSP70 family, hsc74, in preimplantation mouse embryos.

We have investigated the regulation of gene expression of a novel mitochondrial HSP70 family, hsc74 in preimplantation mouse embryos. We used a monoclonal antibody, anti-CSA, which reacts with only one of strain variants of the hsc74. By immunostaining with anti-CSA antibody, the hsc74 protein was constitutively detected in C3H embryos from 1-cell to blastocyst stage, but no signals were detectable in C57BL/6 embryos. To know the timing of paternal genome expression, we examined the expression of hsc74 in (C57BL/6 x C3H)F1 embryos. No positive signals were detectable in embryos before 8-cell stage. In early 8-cell stage weakly positive signals appeared in the peripheral region of the blastomeres. From late 8-cell stage, the protein was intensively detectable and was persistently expressed in all types of cells. We have also applied a sensitive methodology to distinguish genetic variants of hsc74 from C3H and C57BL/6 by reverse transcription polymerase chain reaction followed by single strand conformation polymorphism analysis. In (C57BL/6 x C3H)F1 embryos, the paternal transcripts were first detected in 4-cell embryos, while the maternal transcripts were constantly detectable. These results indicate that the transcripts and proteins of hsc74 were derived only from the maternal gene from 1-cell to 4-cell stages, and that from 4-cell stage the paternal gene is also transcribed, and the significant increase of the paternally derived protein occurred around late 8-cell stage.

Animals↗

PubMed1995

Cell mixing during the early development of mouse aggregation chimera.

Two different inbred strain combinations of mouse aggregation chimeras - C3H/HeN (H-2k) x C57BL/6N (H-2b) and C3H/HeN x BALB/cA (H-2d) were used for cell mixing analysis at two points in time - 24 h after aggregation (just prior to transplantation into foster mothers) and 7.5 days post coitum (p.c.). The cell proportion of two H-2 haplotypes at the blastocyst stage was studied using a fluorescence-labeled monoclonal antibody recognizing a C3H-specific alloantigen - CSA (C3H strain-specific antigen) and laser scanning confocal microscopy. The 7.5-day-old chimeras were sectioned and subsequently processed by sensitive biotinylated antibody - avidin peroxidase immunohistochemical technique. Our results showed that 24 h after aggregation (blastocyst stage), there was equal cell mixing and no mouse strain used in the present study was dominant at this time. In 7.5-day-old C3H/HeN x BALB/cA chimeras, cells of both genotypes were intermingled, but the C3H/HeN strain was dominant in all cases. In contrast, the combination C3H/HeN x C57BL/6N clearly showed reduced numbers of C3H/HeN cells (CSA-positive) in 83% of the chimeras evaluated. Generally, CSA positive cells were found only in randomly distributed small distinct areas representing less than 20% of embryonal cells. Surprisingly, the extraembryonal ectoplacental cone was uniformly CSA positive in some C3H/HeN x C57BL/6N chimeras. Furthermore, in 36% of normally implanted chimeras of both strain combinations progressive degeneration was observed. We suggest that the cell mixing pattern as well as the absolute number of cells derived from each strain in the aggregation chimera can be affected by specific immune interactions involving H-2 haplotype combinations of the allogeneic fetus and the fully immunocompetent host organism, at later points in development.

Animals↗

PubMed1994

Susceptibility of tenascin to degradation by matrix metalloproteinases and serine proteinases.

The degradation of tenascin purified from human melanoma cells was examined by treatment with matrix metalloproteinases (MMPs) and serine proteinases. Among eight different types of proteinases examined, MMP-1, -3, and -7, cathepsin G and leukocyte elastase could digest tenascin, but MMP-2, MMP-9 and thrombin did not. This suggests that tenascin may be readily catabolized by extracellular matrix-degrading proteinases found in the pathophysiological conditions.

Cathepsin G↗

PubMed1994

Survival of steroid 21-hydroxylase-deficient mice without endogenous corticosteroids after neonatal treatment and genetic rescue by transgenesis as a model system for treatment of congenital adrenal hyperplasia in humans.

The genome of mice with the H-2aw18 haplotype has a deletion of approximately 80 kilobases in the H-2 class III region of chromosome 17. Mice that are homozygous for the mutation die soon after birth. A functional form of steroid 21-hydroxylase (21-OHase) is encoded by the deleted DNA fragment, and H-2aw18 homozygotes are deficient in this enzyme. 21-OHase catalyzes the conversion of progesterone to deoxycorticosterone during adrenal steroidogenesis in mice; therefore, H-2aw18 homozygous mice are unable to synthesize corticosteroids. The deleted region also includes the gene for complement component C4, which has a role in the classical pathway of the complement activation cascade. To clarify the cause of the lethality of the mutation, we first administered either an adrenal homogenate or synthetic steroids to newborn mice; as a result, several H-2aw18 homozygotes were rescued. The results demonstrated that the mutant mice die as the result of a defect in adrenal steroidogenesis. The low efficiency of the rescue by treatment of newborns (16.0% by the adrenal homogenate and 14.8% by the synthetic steroids) suggested that mutant mice should be treated prenatally. Moreover, because the 21-OHase gene is expressed before birth, introduction of a gene for 21-OHase should improve the efficiency of rescue. The results of the murine mutation are similar to those of the inherited human disease known as congenital adrenal hyperplasia, which is caused by steroid 21-hydroxylase deficiency. As a model system for treatment of the human disease by genetic therapy, we used transgenic approaches to introduce a recombinant DNA fragment containing the murine genomic gene for 21-OHase into the mutant mice. We produced four lines of transgenic mice, and in all four transgenic lines, the transgene rescued the lethal mutation. The apparent efficiencies of rescue were 80.2%, 80.0%, 68.7%, and 16.7% for the respective lines of transgenic mice. During the course of our experiments, we also found an unexpected property associated with the role of corticosteroids. The H-2aw18 homozygous mice rescued by neonatal treatment survived for a long period without further treatment. This observation indicates that corticosteroids down-stream of 21-OHase in the pathway for adrenal steroidogenesis are not essential for the survival of mice, except during the period immediately after birth.

Adrenal Cortex Hormones↗

PubMed1994

Can tenascin be redundant in cancer development?

Histological and biochemical analyses of tenascin in various human tumors have indicated that tenascin is expressed in various cancer stroma and increased in the serum, getting strong with advancement of its malignancy. Of interest, the prognostic analysis of breast and colon cancers revealed favorable survival and no lymphogenous metastasis in patients whose cancer expressed tenascin strongly. Injection of tenascin nonproducing A431 human epidermoid cancer cells into nude mice resulted in tenascin production by these cells, suggesting cancer cells can make tenascin if necessary. Thus, both carcinoma and adjacent stroma cells may produce tenascin to coordinate the microenvironment surrounding the cancer tissues. Several tenascin variants have been clearly demonstrated to date. With these findings in mind, we would propose that epithelial tenascin supports the carcinoma cell outgrowth, whereas stromal tenascin may block cancer invasion by covering the cancer nest. No obvious phenotype in tenascin gene knockout mice would indicate that tenascin is functionally redundant in developmental processes, yet it may well be very important in progression of cancer.

Animals↗

PubMed1993

Structure and organization of the gene encoding a mouse mitochondrial stress-70 protein.

We have previously found that an antigenic protein specific for C3H strain mouse (C3H strain-specific antigen, CSA) is identical to peptide-binding protein 74 (PBP74). PBP74/CSA is a novel member of the stress-70 protein family in mitochondria. In this study, mouse genomic clones encoding PBP74/CSA, including the 5'- and 3'-flanking regions of the gene, have been isolated and sequenced. The PBP74/CSA gene contained 17 exons interrupted by 16 introns. Two dimeric repeats of the consensus sequence of the heat-shock element are present in the 5'-flanking region of the PBP74/CSA gene. Moreover, the first intron is interrupted within the amino-terminal leader sequence, the pattern of which is similar to that of cytochrome c1 located in the mitochondria.

Amino Acid Sequence↗

PubMed1993

Antigenic protein specific for C3H strain mouse is a mitochondrial stress-70 protein.

Cells derived from C3H strain mouse produce an antigenic protein (CSA) specific for this strain [Kusakabe, M., et al. (1988) J. Cell Biol. 107, 257-265]. To examine the molecular basis of CSA, cDNA cloning of the antigenic protein was carried out. The deduced amino acid sequence demonstrates that CSA is the same protein as peptide-binding protein 74 (PBP74), a novel member of the stress-70 family. However, comparison of the PBP74/CSA sequences between C3H/HeN and BALB/c strain mice reveals the substitution of two amino acids in the substrate-recognition domain of the stress-70 protein. Western blot analysis indicates that one out of these two residues, arginine at residue 578 in the PBP74/CSA sequence of C3H mouse, contributes to the immunogenicity of CSA. Moreover, the subcellular localization of PBP74/CSA in mitochondria is also demonstrated by immunohistochemical analysis using anti-CSA monoclonal antibody. Thus, it is interesting that a genetic marker sequence in mice is located on the gene encoding a mitochondrial stress-70 protein.

Amino Acid Sequence↗

PubMed1993

Expression of tenascin in the developing human small intestine.

The expression of tenascin (Tn), an extracellular matrix glycoprotein, was analyzed in the human small intestine. Three major oligomeric forms of intestinal Tn (320 kDa, 220 kDa and 200 kDa) were identified in both the fetus and the adult. The intestinal 200 kDa form was not found expressed by intestinal mesenchymal cells in culture. During development, the amounts of the 320 and 220 kDa forms remained relatively constant between 9-20 weeks of gestation as compared to sucrase-isomaltase and a-smooth muscle actin while the 200 kDa immunoreactive component increased substantially during this period of active intestinal morphogenesis. Further experiments by microdissection revealed that the 200 kDa component was the major form of Tn in the intestinal villus. These results suggest that this newly identified 200 kDa form of Tn in the small intestine is predominantly expressed in the villus under a developmentally regulated pattern.

Adult↗

PubMed1993

Selective adhesion and proliferation of cells on ion-implanted polymer domains.

We have found that the adhesion and proliferation of endothelial cells can be drastically improved when cultivated on an ion-implanted polymer surface. When the surface of segmented polyurethane, where endothelial cells are not capable of proliferating, is modified by Ne+ or Na+ ion implantation with a fluence of 1 x 10(15) ions/cm2 at an energy of 150 keV, cell adhesion and proliferation occurred selectively on the ion-implanted region irrespective of the ion species. The cells did not proliferate at ion fluences below 1 x 10(14) ions/cm2. Most cells migrated into the ion-implanted domain within 1-2 h, but some of the cells attached outside of the region and then slowly migrated into the region. Ion implantation of polystyrene, on which cells are capable of proliferating, further promoted cell spreading and proliferation, and increased resistance to detachment when the cells were exposed to trypsin.

Animals↗

PubMed1993

Distribution of tenascin in normal cycling human ovary.

Tenascin is an extracellular matrix glycoprotein, which has been reported to be involved in parenchymal-mesenchymal interactions during morphogenesis, wound healing, and carcinogenesis. Tenascin immunolocalization was performed in 51 specimens of morphologically normal human ovaries by using a specific monoclonal antibody against purified human fibroblast tenascin. In preovulatory follicles, no significant immunoreactivity was detected. In functioning corpora lutea, immunoreactivity was present as a fine border around the periphery. In association with the involution of the corpora lutea, marked diffuse tenascin immunostaining in the intercellular space was observed. These data raise the question of whether tenascin may be involved in luteolysis and may play an important role in the ovarian cycle by regulating the involution of corpora lutea.

Cell Adhesion Molecules, Neuronal↗

PubMed1993

Relationships among tenascin expression, DNA ploidy patterns, and multidrug resistance gene product (P-glycoprotein) in human colon carcinoma.

Relationships among tenascin expression, DNA ploidy, and P-glycoprotein were examined in 81 primary human colon cancers and 61 metastatic lymph nodes. First, the DNA ploidy patterns of colon cancerous tissue surrounded (TN+) and not surrounded (TN-) by tenascin immunoreactivity were investigated. Then the expression of P-glycoprotein, one of two multidrug resistance gene products, was examined in TN+ and TN- colon cancer tissues by immunohistochemistry. Aneuploid DNA patterns were observed at high frequency in TN- colon cancer tissues (37/61) and metastatic lymph nodes (44/52). In contrast, diploid DNA patterns were observed predominantly in TN+ colon cancer tissues (50/56). Although P-glycoprotein expression was observed in primary TN+ and TN- colon cancer (9/81), the level of P-glycoprotein expression was not correlated with DNA aneuploidy in TN- colon cancer tissues. Overall, reduced tenascin expression was correlated well with DNA aneuploidy, but no significant correlation was found between DNA aneuploidy and P-glycoprotein appearing when cancer cells become resistant to several anti-cancer drugs. Thus, tenascin may play an important role in preventing colon cancer cells from invading surrounding tissues.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

The mouse chimera during intrauterine stages: immunohistochemical analysis with the C3H strain-specific antibody.

Our objective was to establish an immunohistological method for analysis of chimerism in mouse chimeras at embryonic stages with an anti-C3H strain-specific antigen (CSA) antibody. We developed an effective new method to retain CSA antigenicity with good morphology of embryonic tissues by using microwave irradiation (MWI) for pre-fixation, 95% ethanol/1% acetic acid as post-fixative solution, and polyester wax as embedding material. We used a biotinylated mouse monoclonal anti-CSA antibody, peroxidase-avidin, and silver amplification. These procedures were successful in demonstrating the chimerisms in various tissues of C3H<-->Balb/c chimeras at different embryonic stages and postnatal days. In chimeras at Days 7 and 7.5 post coitum (p.c.), both genotypes were clearly identified and well intermingling in every embryonic tissue (embryonic ectoderm, mesoderm, extra-embryonic ectoderm, ectoplacental cone, amnion, and chorion). Chimerisms at Day 14.5 p.c. were also clearly observed in mesencephalon, neural retina, spinal cord, lung, kidney, and liver. We concluded that the present immunohistological procedures for analysis of chimerism during embryonic periods will give us insightful information about dynamic histological changes such as cell proliferation, migration, selection, and death during organogenesis.

Amnion↗

PubMed1993

Induction of tenascin in cancer cells by interactions with embryonic mesenchyme mediated by a diffusible factor.

Human cancer cell lines A431 and MCF7, which do not produce tenascin (TN) in vitro, were found to produce TN when injected into nude mice or co-cultured with the embryonic mesenchyme. The TN expression in the developing A431 solid tumor was demonstrated by immunohistochemistry and by in situ hybridization. Human TN was detected in culture media by western blot analysis using human specific monoclonal antibody (RCB-1). During tumorigenesis, in the early stage, mouse TN was actively induced and deposited in the peri- and intertumor spaces surrounding the developing tumor. Two days later, TN derived from human epithelial cancer cells was induced and mainly deposited in the intertumor basement membrane. After this stage, tumor cells were actively producing TN. On the other hand, TN induction in non TN-producing cells, such as A431 and MCF7 cell lines, was also observed in vitro. Although cell lines such as NIH-3T3, phi 2, STO, 2H6, 3E5 and CMT315, had no effect on the TN induction, primary cultured embryonic mesenchyme effectively stimulated the TN expression in the cancer cell lines. This mesenchymal effect decreased with age and was entirely lost postnatally. Furthermore, conditioned media from these embryonic mesenchymes could reproduce the same effects on TN induction as observed in the co-culture study. In conclusion, these findings suggest that TN induction in epithelial cancer cells may depend on interactions with the surrounding environment, that these interactions may be mediated by a soluble factor(s) derived from the surrounding mesenchyme and that the TN induction observed in the tumorigenesis may reflect histogenesis during the embryonic period.

Animals↗

PubMed1993

Tenascin expression in normal and abnormal human endometrium.

Tenascin has been recently characterized as an extracellular matrix glycoprotein involved in tissue interactions during fetal development and oncogenesis. In order to study the possible involvement of tenascin in epithelial growth of the human endometrium, we evaluated the expression of tenascin in 84 cases of normal, hyperplastic, or neoplastic human edometrium. The specimens were obtained by curettage and/or biopsy and analyzed by immunohistochemistry utilizing a newly developed monoclonal antibody against human tenascin. Weak periglandular immunoreactivity was observed in 50% of proliferative phase, but not in secretory endometrium. Approximately 60% of endometrial hyperplasia specimens had weak periglandular tenascin immunoreactivity, but its distribution was irregular and not necessarily correlated with degree of cell atypia. Invasive endometrial carcinomas displayed intense and diffuse staining around the carcinoma cells, in addition to thin periglandular immunoreactivity similar to that seen in hyperplasia. The intensity of tenascin staining in endometrial carcinoma was not related to the degree of tumor differentiation. These results suggest that tenascin appears as a result of interactions between neoplastic epithelium and stroma in tumor development and that diffuse and intense staining could be a stromal marker for the invading capacity of human endometrial malignancies.

Cell Adhesion Molecules, Neuronal↗

PubMed1992

Human carcinoma cells synthesize and secrete tenascin in vitro.

Tenascin is an extracellular matrix glycoprotein produced in response to epithelial-mesenchymal interactions that initiate fetal organogenesis, and it is also found in the stroma of benign and malignant neoplasms. Thirty-five human cell lines representing a variety of cancers were examined by immunoprecipitation and polyacrylamide gel electrophoresis of radiolabeled tenascin proteins from conditioned media. Two forms of tenascin with relative molecular masses of 190,000 and 250,000 were identified. Eight cell lines produced both forms. With the exception of myeloid and lymphoid leukemias and Burkitt's lymphoma, all of the mesodermal and neuroectodermal tumor lines were found to synthesize tenascin. Unexpectedly, tenascin was secreted by several mammary and colonic adenocarcinomas as well as by a line derived from normal mammary epithelial cells, and in some cases increased production was induced by transforming growth factor beta in serum-free medium. Cells producing fibronectin but not tenascin attached and spread on plastic culture dishes, while those producing tenascin alone remained suspended in the medium or were rarely attached. Tenascin also inhibited fibronectin-mediated adhesion of MCF7 breast carcinoma cells in vitro. The results suggest that tenascins synthesized and secreted by some cancer cells, especially those of epithelial origin, may have specific roles in determining tumor cell adhesion and ultimately the ability to form invasive outgrowths.

Animals↗