Synthesis of Basal Lamina by Epidermal Cells in vitro

Author(s):  
Sigeru Taniguchi ◽  
Takae Hirone
Keyword(s):  
Author(s):  
E. J. Kollar

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.


2005 ◽  
Vol 73 (2-3) ◽  
pp. 79-87 ◽  
Author(s):  
Eduardo Mitrani ◽  
Guy Nadel ◽  
Eilat Hasson ◽  
Esther Harari ◽  
Yael Shimoni
Keyword(s):  

1981 ◽  
Vol 89 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P Ekblom ◽  
E Lehtonen ◽  
L Saxén ◽  
R Timpl

Conversion of the nephrogenic mesenchyme into epithelial tubules requires an inductive stimulus from the ureter bud. Here we show with immunofluorescence techniques that the undifferentiated mesenchyme before induction expresses uniformly type I and type III collagens. Induction both in vivo and in vitro leads to a loss of these proteins and to the appearance of basement membrane components including type IV collagen. This change correlates both spatially and temporally with the determination of the mesenchyme and precedes and morphological events. During morphogenesis, type IV collagen concentrates at the borders of the developing tubular structures where, by electron microscopy, a thin, often discontinuous basal lamina was seen to cover the first pretubular cell aggregates. Subsequently, the differentiating tubules were surrounded by a well-developed basal lamina. No loss of the interstitial collagens was seen in the metanephric mesenchyme when brought into contact with noninducing tissues or when cultured alone. Similar observations were made with nonnephrogenic mesenchyme (salivary, lung) when exposed to various heterotypic tissues known to induce tubules in the nephrogenic mesenchyme. The sequential shift in the composition of the extracellular matrix from an interstitial, mesenchymal type to a differentiated, epithelial type is so far the first detectable response of the nephrogenic mesenchyme to the tubule-inducing signal.


Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 53-70
Author(s):  
J.-M. Verna

Axons from dorsal root ganglion cells cultured in a serum-free medium on poly-L-lysine or collagen substrates interact differently with dermis and epidermis. The orientation of neurite growth is not changed by encountering mesenchymal cells migrating from the outgrowth zone of a dermal explant, and neurites form close membrane associations with some dermal cells; in contrast, neurites strongly avoid epidermis and deviate around the edge of an epidermal explant. When cultures are grown on polylysine this avoidance behaviour occurs at a distance from the epidermis. It is suppressed in the presence of necrotic epidermal cells. We suggest that this avoidance is due to epidermal diffusible factor(s) which bind preferentially to polylysine. The possibility of an absence of specific recognition cues between neurites and epidermal cells is discussed.


2010 ◽  
Vol 22 (3) ◽  
pp. 209-215 ◽  
Author(s):  
Zanderluce G. Luis ◽  
Kadja Milena G. Bezerra ◽  
Jonny Everson Scherwinski-Pereira

Changes in the leaf structure of plants grown in different conditions have been reported, such as increase in size and density of stomata and reduction in stomatal control, amount of epicuticular wax, and mesophyll thickness, with a high diversity of intercellular spaces. However, these changes are highly variable depending on the physiological and morphological characteristics of each species. The objective of this work was to analyze the adaptability and anatomical plasticity of oil palm seedlings produced after embryo rescue and pre-germinated seeds. Expanded leaves were prepared for evaluation of morphometric data and anatomical structures. It was verified that the environmental conditions in vitro negatively influenced the stomata density, epidermal and hypodermal thickness, and the values for the expansion cells and leaf mesophile. Anatomically, the oil palm leaves present the same tissues composition in both growth conditions, with uniseriate epidermal cells, and tetracitic stomata occurring in both epidermal surfaces. Epidermal cells from in vitro plants are thinner than ones from greenhouse. The midrib of leaves from greenhouse plants are more developed and is composed by only one central vascular bundle, while plants from in vitro cultivation developed three to four collateral vascular bundles.


1993 ◽  
Vol 120 (2) ◽  
pp. 523-535 ◽  
Author(s):  
B E Symington ◽  
Y Takada ◽  
W G Carter

The colocalization of integrins alpha 2 beta 1 and alpha 3 beta 1 at intercellular contact sites of keratinocytes in culture and in epidermis suggests that these integrins may mediate intercellular adhesion (ICA). P1B5, an anti-alpha 3 beta 1 mAb previously reported to inhibit keratinocyte adhesion to epiligrin, was also found to induce ICA. Evidence that P1B5-induced ICA was mediated by alpha 2 beta 1 and alpha 3 beta 1 was obtained using both ICA assays and assays with purified, mAb-immobilized integrins. Selective binding of alpha 2 beta 1-coated beads to epidermal cells or plate-bound alpha 3 beta 1 was observed. This binding was inhibited by mAbs to integrin alpha 3, alpha 2, or beta 1 subunits and could be stimulated by P1B5. We also demonstrate a selective and inhibitable interaction between affinity-purified integrins alpha 2 beta 1 and alpha 3 beta 1. Finally, we show that expression of alpha 2 beta 1 by CHO fibroblasts results in the acquisition of collagen and alpha 3 beta 1 binding. Binding to both of these ligands is inhibited by P1H5, an anti-alpha 2 beta 1 specific mAb. Results of these in vitro experiments suggest that integrins alpha 2 beta 1 and alpha 3 beta 1 can interact and may do so to mediate ICA in vivo. Thus, alpha 3 beta 1 mediates keratinocyte adhesion to epiligrin and plays a second role in ICA via alpha 2 beta 1.


1983 ◽  
Vol 97 (3) ◽  
pp. 849-857 ◽  
Author(s):  
I K Gipson ◽  
S M Grill ◽  
S J Spurr ◽  
S J Brennan

Intact, viable sheets of adult rabbit corneal epithelium, 9 mm in diameter, were prepared by the Dispase II method (Gipson, I. K., and S. M. Grill, 1982, Invest. Ophthalmol. Vis. Sci. 23:269-273). The sheets, freed of the basal lamina, retained their desmosomes and stratified epithelial characteristics, but lacked hemidesmosomes (HD). Epithelial sheets were placed on fresh segments of corneal stroma with denuded basal laminae and incubated in serum-free media for 1, 3, 6, 18, or 24 h. Tissue was processed for electron microscopy, and the number of HD/micron membrane, the number of HDs with anchoring fibrils directly across the lamina densa from them, and the number of anchoring fibrils not associated with HDs were counted. After 6 h in culture, the number of newly formed HD was 82% of controls (normal rabbit corneas), and by 24 h the number had reached 95% of controls. At all time periods studied, 80-86% of HDs had anchoring fibrils directly across the lamina densa from them. Anchoring fibrils not associated with HDs decreased with culture time. These data indicate that the sites where anchoring fibrils insert into the lamina densa may be nucleation sites for new HD formation. Corneal epithelial sheets placed on two other ocular basal laminae, Descemet's membrane and lens capsule, had not formed HDs after 24 h in culture. These two laminae do not have anchoring fibrils associated with them. Rabbit epithelial sheets placed on the denuded epithelial basal lamina of rat and human corneas formed new HDs. Thus, at least in these mammalian species, HD formation may involve some of the same molecular components.


1995 ◽  
Vol 105 (4) ◽  
pp. 597-601 ◽  
Author(s):  
Raul Fleischmajer ◽  
Alan Schechter ◽  
Marco Bruns ◽  
Jerome S. Perlish ◽  
E. Douglas MacDonald ◽  
...  

Development ◽  
1969 ◽  
Vol 21 (2) ◽  
pp. 235-242
Author(s):  
Takesi Yohro

The epidermis of the chick embryo has been widely used for in vitro studies of many developmental problems (Matoltsy, 1960; Billingham & Silvers, 1963). The present attempt to determine the proliferation rate of chick embryonic epidermal cells was expected to provide a base for experimental studies, but a preliminary mitotic count revealed that the number of mitoses varied greatly in different areas. This suggested accumulation of mitoses in some restricted parts of the epidermis, and so a mapping experiment was carried out to determine the distribution of mitoses in this material. The characteristic mitotic pattern which was discovered is described and discussed. About 300 White Leghorn embryos were used: 20 for study of the gross anatomy of scales, 200 for Colcemid treatment and 80 for [3H] thymidine treatment.


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