Intermediate Filament Expression in Astrocytic Neoplasms
Department of Pathology, Los Angeles County-University of Southern California Medical Center 90033. American Journal of Surgical Pathology
(Impact Factor: 5.15).
03/1989; 13(2):141-5. DOI: 10.1097/00000478-198902000-00007
Immunohistochemical analysis of 30 paraffin-embedded astrocytic neoplasms was performed to correlate the expression of intermediate filament proteins with histologic subtype. Each tumor was studied with monoclonal antibodies to keratin, vimentin, desmin, 200-kd neurofilament protein, and glial fibrillary acidic protein (GFAP). Immunoreactivity with the anti-keratin monoclonal antibodies AE1 and AE3 was demonstrated in 24 cases (80%) including 4 of 6 (66%) well-differentiated astrocytomas (WDAs), 10 of 12 (83%) anaplastic astrocytomas (ANAs), and 10 of 12 (83%) glioblastomas multiforme (GBMs). These cases were further studied with the monoclonal antikeratin antibodies 34 beta E12 and 34 beta H11. Of the 24 AE1/AE3-positive cases, 14 (58%) reacted with 34 beta E12. None of the cases was reactive with 34 beta H11. Vimentin expression was demonstrated in 24 cases (80%), including 2 of 6 (33%) WDAs, 11 of 12 (92%) ANAs, and 11 of 12 (92%) GBMs. Coexpression of keratin and vimentin was observed in 20 cases (67%), including 2 of 6 WDAs, 9 of 12 (75%) ANAs, and 9 of 12 (75%) GBMs. Immunoreactivity with GFAP antibody was present in all 30 (100%) cases, but none of the tumors was reactive with antibodies to desmin or 200-kd neurofilament protein. These findings demonstrate that expression of both keratin and vimentin intermediate filaments is common in astrocytic neoplasms regardless of histologic grade.
Available from: Hikmet Basmak
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ABSTRACT: During recent years, the interaction of cell surface molecule, extracellular matrix proteins, and cytoskeletal elements has been a topic for research for the purpose of understanding the mechanisms of pathologic conditions. This study aims to evaluate the expression of CD44, as a cell surface adhesion molecule; fibronectin (FN), as an extracellular and a cell surface protein; vinculin and actin/á-smooth muscle actin (alfa-SMA), as cytoskeletal elements; and the interactions of these proteins in the microenvironment of proliferative vitreoretinopathy (PVR).
This experimental study was designed by the intravitreal Dispase model in rabbits and proteins' expression were evaluated via immunohistochemical staining.
As a cell surface protein, CD44 expression was determined in only four eyes focally and weakly, but in a small number of cells. Among the cytoskeletal proteins, vinculin expression was the most extensive and the strongest in intensity in epi- and subretinal membranes. Alpha-SMA expression was mostly present within small foci of cells. Fibronectin expression was determined in some of the eyes only faintly.
Vinculin seems to be involved in PVR pathogenesis. Variability in co-distribution of the expression of vinculin, FN, and alfa-SMA reflects the dynamic interactions evolving between cell and extracellular matrix during the epi- and subretinal membrane formations. The results of this study were determined not to be in support of the assumption that CD44 has a functional role in the pathogenesis of PVR.
Available from: PubMed Central
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ABSTRACT: In higher vertebrates the cytoskeleton of glial cells, notably astrocytes, is characterized (a) by masses of intermediate filaments (IFs) that contain the hallmark protein of glial differentiation, the glial filament protein (GFP); and (b) by the absence of cytokeratin IFs and IF-anchoring membrane domains of the desmosome type. Here we report that in certain amphibian species (Xenopus laevis, Rana ridibunda, and Pleurodeles waltlii) the astrocytes of the optic nerve contain a completely different type of cytoskeleton. In immunofluorescence microscopy using antibodies specific for different IF and desmosomal proteins, the astrocytes of this nerve are positive for cytokeratins and desmoplakins; by electron microscopy these reactions could be correlated to IF bundles and desmosomes. By gel electrophoresis of cytoskeletal proteins, combined with immunoblotting, we demonstrate the cytokeratinous nature of the major IF proteins of these astroglial cells, comprising at least three major cytokeratins. In this tissue we have not detected a major IF protein that could correspond to GFP. In contrast, cytokeratin IFs and desmosomes have not been detected in the glial cells of brain and spinal cord or in certain peripheral nerves, such as the sciatic nerve. These results provide an example of the formation of a cytokeratin cytoskeleton in the context of a nonepithelial differentiation program. They further show that glial differentiation and functions, commonly correlated with the formation of GFP filaments, are not necessarily dependent on GFP but can also be achieved with structures typical of epithelial differentiation; i.e., cytokeratin IFs and desmosomes. We discuss the cytoskeletal differences of glial cells in different kinds of nerves in the same animal, with special emphasis on the optic nerve of lower vertebrates as a widely studied model system of glial development and nerve regeneration.
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