An analysis of cell shape and the neuroepithelial basal lamina during optic vesicle formation in the mouse embryo

Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 185-200 ◽  
Author(s):  
K.K. Svoboda ◽  
K.S. O'Shea
Keyword(s):  
Electron Microscopy ◽  
Basal Lamina ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Heparan Sulphate ◽  
Intercellular Junctions ◽  
Ultrastructural Analysis ◽  
Vesicle Formation ◽  
Optic Vesicle ◽  
Type Iv

The optic vesicle develops as an evagination of the cephalic neural folds. We have examined the early development of the optic vesicle in Swiss Webster mice using correlated transmission electron microscopy (TEM), scanning electron microscopy (SEM), light microscopic (LM) measurements of cell shape changes, immunohistochemical localization of basal lamina (BL) components (type IV collagen, laminin and heparan sulphate proteoglycan (HSPG)) and ultrastructural analysis of the BL. Like the neuroepithelium in other regions, the low columnar cells of the neural plate in the future optic vesicle region become high columnar, then wedge shaped following constriction of the cell apices to form the C-shaped vesicle. In this region, the cells elongate 2 times their initial height before the neural tube closes, then shorten 20% as the vesicle is completed. Cell apices decrease in width by about one half during vesicle formation. Deposition of BL components was initially even, with type IV collagen and laminin reduced in deposition in regions of outpouching. At later stages the linear, even distribution of all four components was re-established. Ultrastructural analysis confirmed the BL discontinuity and re-establishment and correlated the observed cell shaping alterations with apparent increases in the number of microtubules (during elongation) and microfilaments (during apical constriction). The number of apical intercellular junctions also appeared to increase in number during optic vesicle formation, possibly providing stability and coordination to the evagination process.

scholarly journals Composition and morphology of the follicular basal lamina during atresia of bovine antral follicles

Reproduction ◽  
2002 ◽  
pp. 97-106 ◽  
Author(s):  
HF Irving-Rodgers ◽  
ML Mussard ◽  
JE Kinder ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Basal Cells ◽  
Follicle Growth ◽  
Electron Microscopic ◽  
Antral Follicles ◽  
Type Iv ◽  
Follicle Diameter

The fate of the follicular basal lamina during atresia was investigated using bovine follicles, in which different follicle phenotypes have been observed. These phenotypes include: healthy follicles with rounded basal granulosa cells with an aligned basal lamina or follicles with columnar basal granulosa cells with a basal lamina of many loops (loopy), and atretic follicles in which either the antral granulosa cells (antral atresia) or the basal cells (basal atresia) die first. Loopy lamina and basal atresia occur only in small antral follicles < 5 mm in diameter. Follicles were collected from cattle of unknown reproductive history and processed for immunohistochemistry and electron microscopy, and from animals in which follicle growth had been monitored by daily measurements of follicle diameter by ultrasonography. Electron microscopic observations of dominant follicles during the growth phase, plateau and regression showed that the basal lamina was still visible and intact upon atresia. These follicles had a conventional aligned basal lamina, which they retained, except for some degree of folding, as they progressed into antral atresia. In small follicles (2-5 mm in diameter), the basal cell shape (rounded or columnar) and appearance of the basal lamina (aligned or of many loops) did not appear to be related to the type of atresia. On atresia the follicular basal laminae retained immunoreactive laminin alpha1 and beta2, type IV collagen alpha1 and nidogen. Laminin alpha2, which may come from the theca, was present in the follicular basal lamina of only 22% of healthy follicles, but was expressed very commonly in 71% of the atretic follicles. Laminin alpha2 expression was found in both phenotypes of healthy follicles, antral and basal atretic follicles, and follicles with aligned or loopy basal laminae. It is concluded that the basal lamina is not degraded upon atresia, but does undergo a variety of other changes.

scholarly journals Shift in collagen type as an early response to induction of the metanephric mesenchyme.

1981 ◽  
Vol 89 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P Ekblom ◽  
E Lehtonen ◽  
L Saxén ◽  
R Timpl
Keyword(s):  
Basal Lamina ◽  
Type Iv Collagen ◽  
Early Response ◽  
Type I ◽  
Metanephric Mesenchyme ◽  
Type Iv ◽  
Interstitial Collagens ◽  
Membrane Components

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.

The relationship between emerging neural crest cells and basement membranes in the trunk of the mouse embryo: a TEM and immunocytochemical study

Development ◽  
1986 ◽  
Vol 98 (1) ◽  
pp. 251-268
Author(s):  
J. Sternberg ◽  
S. J. Kimber
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Neural Crest Cell ◽  
Basement Membranes ◽  
Type Iv ◽  
Transmission Electron ◽  
The Relationship ◽  
Crest Cell

The earliest stage of neural crest cell (NCC) migration is characterized by an epitheliomesenchymal transformation, as the cells leave the neural tube. There is evidence that in a number of cell systems this transformation is accompanied by alteration or depletion of associated basement membranes. This study examines the ultrastructural relationship between mouse NCCs and adjacent basement membranes during the earliest stages of migration from the neural tube. Basement membranes were identified by transmission electron microscopy (TEM) and immunofluorescence using antibodies to type-IV collagen. The ultrastructural features of NCCs and their relationship with surrounding tissues were also examined using TEM. In the dorsal region of the neural tube, from which NCCs originate, the basement membrane was depleted or absent, and with the immunofluorescence technique it was shown that this pattern was reflected in a deficit of type-IV collagen. TEM observations indicated that ultrastructurally NCCs differ from their neuroepithelial neighbours only in overall cell shape and their relationship to other cells and the extracellular matrix.

scholarly journals Diagnostic Value of Type IV Collagen Expression in Renal Glomeruli at Alport’s Syndrome

2021 ◽  
Vol 65 (6) ◽  
pp. 42-49
Author(s):  
M. E. Aksenova ◽  
P. E. Povilaitite ◽  
N. E. Konkova ◽  
V. V. Dlin
Keyword(s):  
Electron Microscopy ◽  
Type Iv Collagen ◽  
Immunohistochemical Study ◽  
Immunohistochemical Method ◽  
Alport's Syndrome ◽  
Alport’S Syndrome ◽  
Type Iv ◽  
Renal Glomeruli ◽  
Syndrome Diagnosis

The Alport’s syndrome is the hereditary multisystem disease characterized by the development of the progressive nephropathy. The early diagnosis and subsequent prescription of nephroprotective therapy improves significantly the nephrological prognosis. Purpose of the Study. Determine the value of the immunohistochemical method for the Alport’s syndrome diagnosis. Material and methods. The clinical, laboratory and morphological data of 35 patients with suspected Alport’s syndrome (13 years of age [11; 16]; 18 boys and 17 girls) examined in the Nephrology Department in 2013–2019 were summarized. The study of the renal tissue included the light, immunofluorescence, electron microscopy of the kidney biopsy sample, determination of the expression of α1, α3 and α5 chains of type IV collagen in the renal glomeruli using the immunohistochemical method; the genetic testing was carried out for 26 patients. The children were divided into groups depending on the glomerular expression of α5 chain of type IV collagen: normal (group 1, n=18), decreased (group 2, n=4), negative (group 3, n=13). Results are as the following: The disorder of the expression of α5 chain was detected in ¾ (q = 0.78) patients with genetically confirmed Alport’s syndrome and in almost all children with the X-linked variant of the disease (q = 0.94). Results. Based on the genetic testing, the Alport’s syndrome was confirmed in ¼ of the children of the 1st group (the children with the heterozygous variants of COL4A3, COL4A5 genes) and in all children of the 2nd and 3rd groups (COL4A5 variants). The sensitivity/ specificity of the immunohistochemical study for the Alport’s syndrome diagnosis was 78% /100%, that of the electron microscopy – 93% /87%. The predictive value of the positive/negative result of the immunohistochemical study was 100% /66%, that of the electron microscopy – 95% / 88% compared with 100% / 88% with the combine use of two methods. Conclusion. The determination of the expression of α5 chain of type IV collagen in the renal glomeruli has the independent diagnostic value, but it is inferior to the electron microscopy in the heterozygous variants of the Alport’s syndrome. The high specificity of the immunohistochemical method makes it possible to confirm the Alport’s syndrome in the case of the change in the expression of α5 chain of type IV collagen in the renal glomeruli.

Differential deposition of basement membrane components during formation of the caudal neural tube in the mouse embryo

Development ◽  
1987 ◽  
Vol 99 (4) ◽  
pp. 509-519
Author(s):  
K.S. O'Shea
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Heparan Sulphate ◽  
Heparan Sulphate Proteoglycan ◽  
Sulphate Proteoglycan ◽  
Secondary Neurulation ◽  
Type Iv ◽  
Posterior Neuropore ◽  
Membrane Components ◽  
Basement Membrane Components

The distribution of basement membrane and extracellular matrix components laminin, fibronectin, type IV collagen and heparan sulphate proteoglycan was examined during posterior neuropore closure and secondary neurulation in the mouse embryo. During posterior neuropore closure, these components were densely deposited in basement membranes of neuroepithelium, blood vessels, gut and notochord; although deposition was sparse in the midline of the regressing primitive streak. During secondary neurulation, mesenchymal cells formed an initial aggregate near the dorsal surface, which canalized and merged with the anterior neuroepithelium. With aggregation, fibronectin and heparan sulphate proteoglycan were first detected at the base of a 3- to 4-layer zone of radially organized cells. With formation of a lumen within the aggregate, laminin and type IV collagen were also deposited in the forming basement membrane. During both posterior neuropore closure and secondary neurulation, fibronectin and heparan sulphate proteoglycan were associated with the most caudal portion of the neuroepithelium, the region where newly formed epithelium merges with the consolidated neuroepithelium. In regions of neural crest migration, the deposition of basement membrane components was altered, lacking laminin and type IV collagen, with increased deposition of fibronectin and heparan sulphate proteoglycan.

Comparative analysis of basal lamina type IV collagen α chains, matrix metalloproteinases-2 and -9 expressions in oral dysplasia and invasive carcinoma

2013 ◽  
Vol 115 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Ryo Tamamura ◽  
Hitoshi Nagatsuka ◽  
Chong Huat Siar ◽  
Naoki Katase ◽  
Ichiro Naito ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Matrix Metalloproteinases ◽  
Basal Lamina ◽  
Type Iv Collagen ◽  
Invasive Carcinoma ◽  
Oral Dysplasia ◽  
Type Iv

Macromolecular constituents of basement membranes: a review of current knowledge on their structure and function

1983 ◽  
Vol 61 (8) ◽  
pp. 942-948 ◽  
Author(s):  
Paul G. Scott
Keyword(s):  
Type Iv Collagen ◽  
Current Knowledge ◽  
Heparan Sulphate ◽  
Structural Features ◽  
Structure And Function ◽  
Basement Membranes ◽  
Type Iv ◽  
Type V ◽  
And Function ◽  
Additional Form

Macromolecules which appear to be integral constituents of basement membranes include type IV collagen, the glycoprotein laminin, and heparan sulphate proteoglycan. Another glycoprotein, fibronectin, may occupy an intermediate position between some lining cells and their basement membranes but is not, however, restricted to this location. An additional form of collagen, genetic type V which differs significantly from type IV collagen in structure, appears to be associated with some basement membranes, possibly linking them to underlying connective tissue. The main structural features of each of these macromolecules, as presently understood, are reviewed here as a background to the experimental papers in this "mini-symposium."

Basal lamina glycoproteins laminin and type IV collagen are assembled into a fine-fibered matrix in cultures of a teratocarcinoma-derived endodermal cell line

1982 ◽  
Vol 137 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Ilmo Leivo ◽  
Kari Alitalo ◽  
Leila Risteli ◽  
Antti Vaheri ◽  
Rupert Timpl ◽  
...  
Keyword(s):  
Cell Line ◽  
Basal Lamina ◽  
Type Iv Collagen ◽  
Endodermal Cell ◽  
Type Iv
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