Ultrastructural identification of extracellular matrix and cell surface components during limb morphogenesis in man

Development of the human hand plate (stages 16–17) has been analyzed with emphasis on differentiation of elements within the extracellular matrix and the composition of the mesenchymal cell surface. The epithelial—mesenchymal interface contains a basal lamina and a sublaminar matrix exhibiting: (a) collagen fibrils with characteristic 63–64 nm banding; (b) non-banded filaments, 10–15 nm in diameter; (c) ruthenium red-positive particles, 12–15 nm in diameter; and (d) attenuated threads, 3·5–5·0 nm in diameter which interconnect particles, fibrils, filaments and the basal lamina. Processes of mesenchymal cells penetrate this matrix network. In addition to staining with ruthenium red, components of basal laminae bind to ferritin-conjugated Concanavalin A, greatest binding being localized on the mesenchymal surface of the lamina. Asymmetry of binding is removed by incubation of exposed laminae with trypsin (5 µg/ml). Regional differences in these staining and binding characteristics within the subepithelial matrix have not been observed in the hand plate. However, precartilaginous extracellular zones deep within the plate are notably unstructured in comparison to the sublaminar region. Ruthenium red-positive materials at mesenchymal cell surfaces display sensitivity to testicular hyaluronidase, Pronase and trypsin but resist removal with neuraminidase and EDTA. These features of the substrate in situ may be important in the regulation of mesenchymal cell behavior during limb morphogenesis in man.

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Acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activity distribution pattern in early developing chick limbs

Development ◽

10.1242/dev.86.1.89 ◽

1985 ◽

Vol 86 (1) ◽

pp. 89-108

Author(s):

Carla Falugi ◽

Margherita Raineri

Keyword(s):

Plasma Membrane ◽

Basal Lamina ◽

Ache Activity ◽

Quantitative Methods ◽

Mesenchymal Cell ◽

Mesenchymal Cells ◽

Regional Localization ◽

Stage Of Development ◽

Limb Morphogenesis ◽

Cell Processes

The distribution of acetylcholinesterase (AChE) and pseudocholinesterase (BuChE) activities was studied by histochemical, quantitative and electrophoretical methods during the early development of chick limbs, from stage 16 to stage 32 H.H. (Hamburger & Hamilton, 1951). By quantitative methods, true AChE activity was found, and increased about threefold during the developmental period, together with a smaller amount of BuChE which increased more rapidly in comparison with the AChE activity from stage 25 to 32 H.H. Cholinesterase activity was histochemically localized mainly in interacting tissues, such as the ectoderm (including the apical ectodermal ridge) and the underlying mesenchyme. True AChE was histochemically localized around the nuclei and on the plasma membrane of ectodermal (including AER) and mesenchymal cells, and at the plasma membrane of mesenchymal cell processes reaching the basal lamina between the ectoderm and the mesenchyme. AChE together with BuChE activity was found in the basal lamina between the ectoderm and the mesenchyme, in underlying mesenchymal cells and in deeper mesenchymal cells, especially during their transformation into unexpressed chondrocytes. During limb morphogenesis, the cellular and regional localization of the enzyme activities showed variations depending on the stage of development and on the occurrence of interactions. The possibility of morphogenetic functions of the enzyme is discussed.

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Response of basal epithelial cell surface and Cytoskeleton to solubilized extracellular matrix molecules.

The Journal of Cell Biology ◽

10.1083/jcb.91.1.45 ◽

1981 ◽

Vol 91 (1) ◽

pp. 45-54 ◽

Cited By ~ 227

Author(s):

S P Sugrue ◽

E D Hay

Keyword(s):

Extracellular Matrix ◽

Cell Surface ◽

Basal Cell ◽

Actin Filaments ◽

Cell Cortex ◽

Collagen Gels ◽

Basal Surface ◽

Extracellular Matrix Components ◽

Cytoplasmic Processes

Corneal epithelium removed from underlying extracellular matrix (ECM) extends numerous cytoplasmic processes (blebs) from the formerly smooth basal surface. If blebbing epithelia are grown on collagen gels or lens capsules in vitro, the basal surface flattens and takes on the smooth contour typical of epithelium in contact with basal lamina in situ. This study examines the effect of soluble extracellular matrix components on the basal surface. Corneal epithelia from 9- to 11-d-old chick embryos were isolated with trypsin-collagenase or ethylenediamine tetraacetic acid, then placed on Millipore filters (Millipore Corp., Bedford, Mass.), and cultured at the medium-air interface. Media were prepared with no serum, with 10% of calf serum, or with serum from which plasma fibronectin was removed. Epithelia grown on filters in this medium continue to bleb for the duration of the experiments (12-14 h). If soluble collagen, laminin, or fibronectin is added to the medium, however, blebs are withdrawn and by 2-6 h the basal surface is flat. Epithelia grown on filters in the presence of albumin, IgG, or glycosaminoglycans continue to bleb. Epithelia cultured on solid substrata, such as glass, also continue to bleb if ECM is absent from the medium. The basal cell cortex in situ contains a compact cortical mat of filaments that decorate with S-1 myosin subfragments; some, if not all, of these filaments point away from the plasmalemma. The actin filaments disperse into the cytoplasmic processes during blebbing and now many appear to point toward the plasmalemma. In isolated epithelia that flatten in response to soluble collagens, laminin, and fibronectin, the actin filaments reform the basal cortical mat typical or epithelial in situ. Thus, extracellular macromolecules influence and organize not only the basal cell surface but also the actin-rich basal cell cortex of epithelial cells.

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HtrA1 Is Specifically Up-Regulated in Active Keloid Lesions and Stimulates Keloids Development

10.20944/preprints201710.0136.v1 ◽

2017 ◽

Author(s):

Satoko Yamawaki ◽

Motoko Naitoh ◽

Hiroshi Kubota ◽

Rino Aya ◽

Yasuhiro Katayama ◽

...

Keyword(s):

Gene Expression ◽

Extracellular Matrix ◽

Cell Proliferation ◽

In Situ Hybridization ◽

Cell Surface ◽

Western Blot ◽

Blot Analysis ◽

Normal Skin ◽

Immunohistochemical Analysis

1) Background: Keloids occur after the failure during the wound-healing process, persist the inflammation and are refractory to various treatments. The pathogenesis of keloids is still unclear. We previously analyzed the gene expression profiles in keloid tissue using microarray and Northern blot analysis and found that HtrA1 was markedly upregulated in the keloid lesions. HtrA1 is a member of the HtrA family of serine protease, has been suggested to play a role in the pathogenesis of various diseases including age-related macular degeneration and osteoarthritis by modulating proteins in extracellular matrix or cell surface. We focused on HtrA1, analyzed the localization and the role in keloid pathogenesis. 2) Methods: Twenty seven keloid patients and seven unrelated patients were enrolled in this study. We performed in situ hybridization analysis, immunohistochemical analysis, western blot analysis and cell proliferation assay. 3) Results: First, the fibroblast-like cells expressed HtrA1 higher in the active keloid lesions than in the surrounding lesions in situ hybridization. Second, the proportion of HtrA1-positive cells in keloid was higher than that of in normal skin significantly in immunohistochemical analysis. Third, HtrA1 protein was up-regulated, relative to normal skin tissue samples in western blot analysis. Finally, silencing of HtrA1 gene expression suppressed the cell proliferation significantly. 4) Conclusion: HtrA1 was highly expressed in keloid tissues and the suppression of HtrA1 gene inhibited the proliferation of keloid-derived fibroblasts. HtrA1 may promote keloid development through accelerating cell proliferation and remodeling keloid-specific extracellular matrix or cell surface molecules. HtrA1 is suggested to have an important role in keloid pathogenesis.

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Fine structural analysis of limb development in the wingless mutant chick embryo

Development ◽

10.1242/dev.68.1.69 ◽

1982 ◽

Vol 68 (1) ◽

pp. 69-86

Author(s):

Linwood M. Sawyer

Keyword(s):

Gap Junctions ◽

Basal Lamina ◽

Limb Development ◽

Mesenchymal Cell ◽

Ruthenium Red ◽

Limb Bud ◽

Normal Embryo ◽

Limb Buds ◽

Transmission Electron ◽

Dense Vesicles

The fine structure of the normal and wingless chick limb bud was examined with scanning and transmission electron microscopy. The apical ectodermal ridge (AER) of the normal limb bud was composed of pseudostratined columnar cells. These cells contained gap junctions, electron-dense vesicles, and numerous microtubules and microfilaments that were oriented perpendicularly to the basal lamina. Microfilaments were also found coursing transversely in the basal cell cytoplasm. The ectoderm of the wingless mutant limb bud lacked a well-developed AER and resembled the dorsal and ventral ectoderm of the normal embryo. Gap junctions and electron-dense vesicles found in the AER of the normal limb bud were not apparent in the mutant ectoderm. The normal-limb bud mesoderm is composed of stellate cells that are oriented at right angles to the overlying ectoderm. There is a prominent subectodermal space that is traversed by numerous mesenchymal cell filopodia. The mesodermal cells of the mutant limb bud are compact and round and have short stubby filopodia, while the cells of the adjacent flank mesoderm are stellate. The subectodermal space is absent and the mesodermal cells are in intimate association with the basal lamina of the overlying ectoderm. Ruthenium red was employed as an extracellular marker for glycosaminoglycan$. No differences were found in the distribution of these substances in normal and mutant limb buds. In severalcases the basal lamina of the mutant limb bud ectoderm was discontinuous aqd the lamina lucida wasnot apparent. The results indicate that the mutation has an effect on the limb buds' ability to maintain a well-developed AER and basal lamina. It also suggest$ that the wingless gene affects the shape and possibly the mobility of the limb-bud mesoderm cells.

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Regulation of Mesenchymal Cell Growth During Human Limb Morphogenesis Through Glycosaminoglycan-Adenylate Cyclase Interaction at the Cell Surface

Ciba Foundation Symposium 40 - Embryogenesis in Mammals - Novartis Foundation Symposia ◽

10.1002/9780470720226.ch14 ◽

2008 ◽

pp. 275-300

Author(s):

Robert O. Kelley ◽

Gene C. Palmer

Keyword(s):

Cell Growth ◽

Cell Surface ◽

Adenylate Cyclase ◽

Mesenchymal Cell ◽

Limb Morphogenesis ◽

Human Limb

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Trace Amine-Associated Receptor 1 Trafficking to Cilia of Thyroid Epithelial Cells

Cells ◽

10.3390/cells10061518 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1518

Author(s):

Maria Qatato ◽

Vaishnavi Venugopalan ◽

Alaa Al-Hashimi ◽

Maren Rehders ◽

Aaron D. Valentine ◽

...

Keyword(s):

Cell Surface ◽

Cell Lines ◽

Human Thyroid ◽

Apical Plasma Membrane ◽

Thyroid Cell ◽

Thyroid Cells ◽

Trace Amine ◽

Rat Thyroid

Trace amine-associated receptor 1 (rodent Taar1/human TAAR1) is a G protein-coupled receptor that is mainly recognized for its functions in neuromodulation. Previous in vitro studies suggested that Taar1 may signal from intracellular compartments. However, we have shown Taar1 to localize apically and on ciliary extensions in rodent thyrocytes, suggesting that at least in the thyroid, Taar1 may signal from the cilia at the apical plasma membrane domain of thyrocytes in situ, where it is exposed to the content of the follicle lumen containing putative Taar1 ligands. This study was designed to explore mouse Taar1 (mTaar1) trafficking, heterologously expressed in human and rat thyroid cell lines in order to establish an in vitro system in which Taar1 signaling from the cell surface can be studied in future. The results showed that chimeric mTaar1-EGFP traffics to the apical cell surface and localizes particularly to spherical structures of polarized thyroid cells, procilia, and primary cilia upon serum-starvation. Moreover, mTaar1-EGFP appears to form high molecular mass forms, possibly homodimers and tetramers, in stably expressing human thyroid cell lines. However, only monomeric mTaar1-EGFP was cell surface biotinylated in polarized human thyrocytes. In polarized rat thyrocytes, mTaar1-EGFP is retained in the endoplasmic reticulum, while cilia were reached by mTaar1-EGFP transiently co-expressed in combination with an HA-tagged construct of the related mTaar5. We conclude that Taar1 trafficking to cilia depends on their integrity. The results further suggest that an in vitro cell model was established that recapitulates Taar1 trafficking in thyrocytes in situ, in principle, and will enable studying Taar1 signaling in future, thus extending our general understanding of its potential significance for thyroid autoregulation.

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