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Biomedical subjects

M Takeichi

Publications and source records attributed to M Takeichi.

At least 181 records · Page 10Linked to original sources
PubMed1989

Expression and role of E- and P-cadherin adhesion molecules in embryonic histogenesis. I. Lung epithelial morphogenesis.

The role of Ca2+-dependent cell-cell adhesion molecules, E- and P-cadherins, in the histogenesis of mouse embryonic lung was studied. All epithelial cells of the lung express both E- and P-cadherin at the early developmental stage. P-cadherin, however, gradually disappears during development, initially from the main bronchi and eventually from all epithelial cells. When a monoclonal antibody to E-cadherin (ECCD-1) was added to monolayer cultures of lung epithelial cells, it induced a partial disruption of their cell-cell adhesion, while a monoclonal antibody to P-cadherin (PCD-1) showed a subtle effect. A mixture of the two antibodies, however, displayed a synergistic effect. We then tested the effect of the antibodies on the morphogenesis of lung primordia using an organ culture system. In control media, the explants formed typical bronchial trees. In the presence of ECCD-1, the explants grew up at the same rate as in the control, but their morphogenesis was affected. The control explants formed round epithelial lobules with an open luminal space at the tips of the bronchial trees, whereas the lobules of explants incubated with ECCD-1 tended to be flat and devoid of the luminal space. PCD-1 showed a similar but very small effect. A mixture of the two antibodies, however, showed a stronger effect: the branching of epithelia was partially suppressed and the arrangement of epithelial cells was distorted in many places. These results suggest that E- and P-cadherin have a synergistic role in the organization of epithelial cells in lung morphogenesis.

Animals↗
PubMed1989

Expression and role of E- and P-cadherin adhesion molecules in embryonic histogenesis. II. Skin morphogenesis.

Expression and the role of E- and P-cadherin in the histogenesis of the surface epidermis and hair follicles were examined using the upper lip skin of the mouse. P-cadherin is expressed exclusively in the proliferating region of these tissues, that is in the germinative layer of the surface epidermis, the outer root sheath and the hair matrix. E-cadherin is coexpressed in these layers but this molecule was also detected in non-proliferating regions such as the intermediate layer of the surface epidermis and the immature regions of the inner root sheath. Neither P- nor E-cadherin was detected in fully keratinized layers such as the horny layer of the surface epidermis, the outermost layer of the outer root sheath and the mature hair fibres. These two cadherins were not detected in dermal cells. We cultured pieces of the upper lip skin in vitro in the absence or presence of a monoclonal antibody to E-cadherin (ECCD-1) or to P-cadherin (PCD-1). In control cultures, skin morphogenesis normally occurred in a pattern whereby the hair follicles grew and dermal cells were condensed to form the dermal sheath. A mixture of ECCD-1 and PCD-1, however, induced abnormal morphogenesis in the skin in several respects. (1) The cuboidal or columnar arrangement of basal epithelial cells was distorted. (2) Hair follicles were deformed. (3) Condensation of dermal cells was suppressed, causing a homogeneous distribution of these cells. These results suggest that cadherins present in epidermal cells are involved not only in maintaining the arrangement of these cells but also in inducing dermal condensation.

Animals↗
PubMed1989

Characterization of murine bone marrow and spleen-derived stromal cells: analysis of leukocyte marker and growth factor mRNA transcript levels.

Stromal cells are believed to regulate lympho-hematopoiesis through direct cell-cell interactions and the release of growth factors. Many questions remain, however, about their lineage derivation and functional heterogeneity. We previously prepared a panel of stromal cell lines from murine spleen and bone marrow and characterized them based on their ability to support lymphocyte growth in long-term cultures. These cells are now compared with respect to their expression of various immunoglobulin superfamily and cytokine genes by Northern blot analysis. These results indicate that although stromal cells appear to be mesodermal in origin, they are not closely related developmentally to the hematopoietic progenitor cells they support. The potential production of at least six cytokines was demonstrated. All clones constitutively expressed mRNA for macrophage colony stimulating factor, interleukin-6, transforming growth factor beta and neuroleukin. The most potent lymphocyte supporting clones also made interleukin 7 constitutively. Previous findings had suggested that these clones responded to exogenous stimuli and this has now been demonstrated in terms of induced expression of IL-6 and G/M-CSF mRNA. Interleukin 6 mRNA levels were markedly upregulated by exposure of cells to LPS, TNF, IL-1, IL-6, IL-7, and EGF. G/M-CSF mRNA levels were "superinduced" by the combination of LPS and cycloheximide, a protein synthesis inhibitor. These responses are similar to ones documented by investigators working with endothelial cells and fibroblasts. Together, these data suggest that stromal cells are a multifunctional component of the lymphopoietic microenvironment and may be active participants in a complex, cytokine-mediated regulatory network.

Animals↗
PubMed1988

Cell binding function of E-cadherin is regulated by the cytoplasmic domain.

Cadherins are a family of transmembrane glycoproteins responsible for Ca2+-dependent cell-cell adhesion. Their amino acid sequences are highly conserved in the cytoplasmic domain. To study the role of the cytoplasmic domain in the function of cadherins, we constructed expression vectors with cDNAs encoding the deletion mutants of E-cadherin polypeptides, in which the carboxy terminus was truncated at various lengths. These vectors were introduced into L cells by transfection, and cell lines expressing the mutant E-cadherin molecules were isolated. In all transfectants obtained, the extracellular domain of the mutant E-cadherins was exposed on the cell surface, and had normal Ca2+-sensitivity and molecular size. However, these cells did not show any Ca2+-dependent aggregation, indicating that the mutant molecules cannot mediate cell-cell binding. The mutant E-cadherin molecules could be released from cells by nonionic detergents, whereas a fraction of normal E-cadherin molecules could not be extracted with the detergent and appeared to be anchored to the cytoskeleton at cell-cell junctions. These results suggest that the cytoplasmic domain regulates the cell-cell binding function of the extracellular domain of E-cadherin, possibly through interaction with some cytoskeletal components.

Antigens, Surface↗
PubMed1988

Expressed recombinant cadherins mediate cell sorting in model systems.

Cadherins are cell-surface glycoproteins responsible for Ca2+-dependent cell-to-cell adhesion. E- or P-cadherin was transfected into L cells, which normally have little cadherin activity, and cellular aggregation of the resulting transfectants was observed to be a function of the cadherin molecule expressed. Transfected cells preferentially adhered to cells expressing the same cadherin subclass. Furthermore, in reconstituted embryonic lung tissue, E-cadherin-expressing L cells were associated with epithelial tubules expressing E-cadherin, while untransfected L cells associated with mesenchymal cells. These results provide the first direct evidence that the differential expression of cadherins can play a role in cell sorting in heterogeneous cell populations.

Agglutination↗
PubMed1988

Guidance of optic nerve fibres by N-cadherin adhesion molecules.

The dendritic branches (neurites) of developing neurons migrate along specific pathways to reach their targets. It has been suggested that this migration is guided by factors present on the surface of other neurons or glial cells. The molecular nature of such factors, however, remains to be elucidated. N-cadherin is a cell-surface glycoprotein which belongs to the cadherin family of cell-cell adhesion molecules. This adhesion molecule is expressed in various neuronal cells as well as in glial cells of the central and peripheral nervous systems in vertebrate embryos and recent immunological studies suggested that N-cadherin may play a role in guiding the migration of neurites on myotubes or astrocytes. To further examine this possibility, we used a molecular-genetic approach; that is, we examined the outgrowth of chicken embryonic optic axons on monolayer cultures of Neuro 2a or L cells transfected with the complementary DNA encoding chicken N-cadherin. The data indicate that N-cadherin is used as a guide molecule for the migration of optic axons on cell surfaces.

Animals↗
PubMed1988

Exogenous delta-crystallin gene expression as probe for differentiation of teratocarcinoma stem cells.

We developed an experimental system in which differentiation of teratocarcinoma stem cell is probed by expression of stably introduced exogenous genes. We used chicken delta-crystallin gene (delta gene) and its derivative (Mo delta gene) driven by long terminal repeat (LTR) promoter of Moloney murine leukemia virus (Mo-MuLV). Neither of the genes was expressed in the undifferentiated condition. Differentiation to primitive endoderm induced by retinoic acid (RA) led to expression of delta but not Mo delta, while differentiation to more advanced endodermal cells by RA plus dibutyryl cAMP elicited Mo delta expression in addition to delta. These results are interpreted as a consequence of differential activation/suppression of gene expression through enhancer elements associated with the genes.

Alkaline Phosphatase↗
PubMed1988

Role of N-cadherin cell adhesion molecules in the histogenesis of neural retina.

We investigated the role of N-cadherin cell adhesion molecules in the histogenesis of the chicken neural retina. In the undifferentiated retina of early embryos, N-cadherin is almost evenly distributed. With differentiation, N-cadherin was gradually localized in particular cell layers. In the 8.5 to 10.5 day embryos, N-cadherin was most abundant in the optic nerve fiber layer, the plexiform layers and the outer limiting membrane. Thereafter, this molecule gradually diminished from most parts of the retina, except in the outer limiting membrane. When incubated with Fab fragments of a polyclonal antibody to N-cadherin, retinas of early embryos tended to dissociate and could not be maintained as a tissue mass. Retinas from older embryos were not dissociated by the Fab, but their morphogenesis was severely affected. We conclude that N-cadherin is essential for maintaining the overall structure of the undifferentiated retina, but during development, its role becomes restricted to maintaining more specific regions of the tissue. We also suggest that there might be additional, unidentified cadherin-like molecules in the retina.

Animals↗
PubMed1988

Identification of a gene family of cadherin cell adhesion molecules.

Cadherins are a group of functionally related glycoproteins responsible for the Ca2+-dependent cell-cell adhesion mechanism. They are divided into subclasses, such as E-, P- and N-cadherin, which are distinct in immunological specificities and tissue distribution. Cell aggregation experiments suggest that these molecules have subclass specificities in cell-cell binding and are involved in selective cell adhesions. Analysis of amino acid sequences deduced from the nucleotide sequences of cDNAs encoding cadherins demonstrated that they are integral membrane proteins and share common sequences throughout their entire length; average similarity in the sequences among them is in a range of 50-60%. This result provided evidence that cadherins constitute a gene family which encodes adhesion molecules with different specificities. We also showed that, when cells with little cadherin activity were transfected with cadherin cDNAs, they acquired the cadherin-mediated adhesion properties.

Animals↗
PubMed1988

Cloning and expression of cDNA encoding a neural calcium-dependent cell adhesion molecule: its identity in the cadherin gene family.

The neural cadherin (N-cadherin) is a Ca2+-dependent cell-cell adhesion molecule detected in neural tissues as well as in non-neural tissues. We report here the nucleotide sequence of the chicken N-cadherin cDNA and the deduced amino acid sequence. The sequence data suggest that N-cadherin has one transmembrane domain which divides the molecule into an extracellular and a cytoplasmic domain; the extracellular domain contains internal repeats of characteristic sequences. When the N-cadherin cDNA connected with virus promoters was transfected into L cells which have no endogenous N-cadherin, the transformants acquired the N-cadherin-mediated aggregating property, indicating that the cloned cDNA contained all information necessary for the cell-cell binding action of this molecule. We then compared the primary structure of N-cadherin with that of other molecules defined as cadherin subclasses. The results showed that these molecules contain common amino acid sequences throughout their entire length, which confirms our hypothesis that cadherins make a gene family.

Amino Acid Sequence↗
PubMed1988

The cadherins: cell-cell adhesion molecules controlling animal morphogenesis.

Cadherins are a family of glycoproteins involved in the Ca2+-dependent cell-cell adhesion mechanism which is detected in most kinds of tissues. Inhibition of the cadherin activity with antibodies induces dissociation of cell layers, indicating a fundamental importance of these molecules in maintaining the multicellular structure. Cadherins are divided into subclasses, including E-, N- and P-cadherins. While all subclasses are similar in molecular weight, Ca2+- and protease-sensitivity, each subclass is characterized by a unique tissue distribution pattern and immunological specificity. Analysis of amino acid sequences deduced from cDNA encoding these molecules showed that they are integral membrane proteins of 723-748 amino acids long and share common sequences; similarity in the sequences between subclasses is in a range of 50-60% when compared within a single animal species. L cells, with very little endogenous cadherin activity, transfected with the cadherin cDNA acquired high cadherin-mediated aggregating activity. Their colony morphology was altered by the ectopic expression of cadherins from the dispersed type to the compact type, providing direct evidence for a key role of cadherins in cell-cell adhesion. It has been suggested that cadherins bind cells by their homophilic interactions at the extracellular domain and are associated with actin bundles at the cytoplasmic domain. It appears that each cadherin subclass has binding specificity and this molecular family is involved in selective cell-cell adhesion. In development, the expression of each cadherin subclass is spatiotemporally regulated and associated with a variety of morphogenetic events; e.g. the termination or initiation of expression of a cadherin subclass in a given cell collective is correlated with its segregation from or connection with other cell collectives. Antibodies to cadherins were shown to perturb the morphogenesis of some embryonic organs in vitro. These observations suggest that cadherins play a crucial role in construction of tissues and the whole animal body.

Animals↗
PubMed1987

Isolation of placental cadherin cDNA: identification of a novel gene family of cell-cell adhesion molecules.

Ca2+-dependent cell--cell adhesion molecules, termed cadherins, are classified into subclasses with different tissue distributions and distinct cell--cell binding specificities. We report the cloning of cDNA encoding a cadherin present in the placenta which is called P-cadherin. The deduced sequence encodes a polypeptide of 822 amino acids with the characteristic features of integral membrane proteins. A computer search of the amino acid sequence homology of P-cadherin against itself showed that this molecule contains internal repeats in the extracellular domain. Comparison of the primary structure of P-cadherin with that of the epithelial cadherin (E-cadherin) showed that there is 58% homology in their amino acid sequences. These results provide evidence for our hypothesis that cadherins constitute a gene family.

Amino Acid Sequence↗
PubMed1987

Spatial and temporal expression pattern of N-cadherin cell adhesion molecules correlated with morphogenetic processes of chicken embryos.

N-cadherin is a Ca2+-dependent cell-cell adhesion molecule, which was identified in brain cells of mouse and chicken. In the present study, we have determined the pattern of expression of N-cadherin in chicken embryos at various stages by means of immunohistochemistry. N-cadherin was expressed in cells derived from all three primary germ layers. Its expression was transient in many tissues but permanent in others. The transient expression occurred in nephric tubules, skeletal muscles, mesenchymal tissues, endodermal organs, and epidermis, while the permanent expression occurred in nervous systems, lens, and myocardiac cells. Appearance or disappearance of N-cadherin could be generally correlated with morphogenetic events, such as rearrangement, segregation, or association of cells. Comparison of the expression pattern of N-cadherin with that of L-CAM and N-CAM determined by other workers suggests that there is some mechanism controlling expression of multiple classes of adhesion molecules. The pattern of expression of N-cadherin was generally complementary to that of L-CAM; that is, if N-cadherin appeared, L-CAM disappeared or vice versa. We also found cases in which N-cadherin was expressed in the same local regions as L-CAM. The distribution of N-cadherin was similar to that of N-CAM with some exceptions. Thus, N-cadherin and other cell-cell adhesion molecules seem to be expressed under a precise spatial and temporal control so as to be associated with a variety of morphogenetic events during development.

Animals↗
PubMed1987

Adhesion molecules during somitogenesis in the avian embryo.

In avian embryos, somites constitute the morphological unit of the metameric pattern. Somites are epithelia formed from a mesenchyme, the segmental plate, and are subsequently reorganized into dermatome, myotome, and sclerotome. In this study, we used somitogenesis as a basis to examine tissue remodeling during early vertebrate morphogenesis. Particular emphasis was put on the distribution and possible complementary roles of adhesion-promoting molecules, neural cell adhesion molecule (N-CAM), N-cadherin, fibronectin, and laminin. Both segmental plate and somitic cells exhibited in vitro calcium-dependent and calcium-independent systems of cell aggregation that could be inhibited respectively by anti-N-cadherin and anti-N-CAM antibodies. In vivo, the spatio-temporal expression of N-cadherin was closely associated with both the formation and local disruption of the somites. In contrast, changes in the prevalence of N-CAM did not strictly accompany the remodeling of the somitic epithelium into dermamyotome and sclerotome. It was also observed that fibronectin and laminin were reorganized secondarily in the extracellular spaces after CAM-mediated contacts were modulated. In an in vitro culture system of somites, N-cadherin was lost on individual cells released from somite explants and was reexpressed when these cells reached confluence and established intercellular contacts. In an assay of tissue dissociation in vitro, antibodies to N-cadherin or medium devoid of calcium strongly and reversibly dissociated explants of segmental plates and somites. Antibodies to N-CAM exhibited a smaller disrupting effect only on segmental plate explants. In contrast, antibodies to fibronectin and laminin did not perturb the cohesion of cells within the explants. These results emphasize the possible role of cell surface modulation of CAMs during the formation and remodeling of some transient embryonic epithelia. It is suggested that N-cadherin plays a major role in the control of tissue remodeling, a process in which N-CAM is also involved but to a lesser extent. The substratum adhesion molecules, fibronectin and laminin, do not appear to play a primary role in the regulation of these processes but may participate in cell positioning and in the stabilization of the epithelial structures.

Animals↗
PubMed1987

Calcium-dependent cell-cell adhesion molecules (cadherins): subclass specificities and possible involvement of actin bundles.

Cadherins are a family of cell-cell adhesion molecules and are divided into subclasses with distinct adhesive specificities and tissue distribution. Here we examined the distribution of cadherins at contact sites between cells expressing the same or different cadherin subclasses. Each cadherin was concentrated at the boundary between cells expressing an identical cadherin subclass, irrespective of the cell types connected. However, such localization decreased or disappeared at the boundary between cells containing different cadherin subclasses. We also found that the localization of cadherins precisely coincided with that of actin bundles; both were detected at the apical region of cell sheets. This co-localization was retained even after cells were either treated with cytochalasin D or extracted with the detergent NP40. These results suggest that each cadherin subclass preferentially interacts with its own molecular type at intercellular boundaries, and that cadherin molecules may be associated with actin-based cytoskeletal elements.

Actins↗
PubMed1987

A case of chronic subdural hematoma with anxiety states and concomitant regression-like symptoms.

The authors described an epileptic suffering from head trauma in whom anxiety states and concomitant regression-like symptoms masked the diagnosis of chronic subdural hematoma. Along with the occurrence of chronic subdural hematoma, psychic symptoms were manifested including the anxiety and regression of personality. However, after the chronic subdural hematoma was neurosurgically evacuated, these psychic symptoms gradually disappeared. In the study of organic and symptomatic psychosis, Mackenzie and Popkin (1983) have proposed the concept of an organic anxiety syndrome on the ground that DSM-III provides no organic equivalent for anxiety disorders. Therefore, we presented a case of chronic subdural hematoma in which the direct effect on CNS of this pathological condition was considered to bring about the above-mentioned anxiety disorders with regression-like symptoms.

Adult↗