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Tumor Necrosis Factor‐α and Basic Fibroblast Growth Factor Decrease Glial Fibrillary Acidic Protein and Its Encoding mRNA in Astrocyte Cultures and Glioblastoma Cells
Author(s) -
Murphy Greer M.,
Lee Yuen LIng,
Jia XiaoChi,
Yu Albert C. H.,
Majewska Anna,
Song Yaoli,
Schmidt Karen,
Eng Lawrence F.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65062716.x
Subject(s) - glial fibrillary acidic protein , astrocyte , tumor necrosis factor alpha , basic fibroblast growth factor , biology , cytokine , gfap stain , microbiology and biotechnology , growth factor , immunology , endocrinology , biochemistry , immunohistochemistry , receptor , central nervous system
Tumor necrosis factor‐α is a pluripotent cytokine that is reportedly mitogenic to astrocytes. We examined expression of the astrocyte intermediate filament component glial fibrillary acidic protein in astrocyte cultures and the U373 glioblastoma cell line after treatment with tumor necrosis factor‐α. Treatment with tumor necrosis factor‐α for 72 h resulted in a decrease in content of glial fibrillary acidic protein and its encoding mRNA. At the same time, tumor necrosis factor‐α treatment increased the expression of the cytokine interleukin‐6 by astrocytes. The decrease in glial fibrillary acidic protein expression was greater when cells were subconfluent than when they were confluent. Thymidine uptake studies demonstrated that U373 cells proliferated in response to tumor necrosis factor‐α, but primary neonatal astrocytes did not. However, in both U373 cells and primary astrocytes tumor necrosis factor‐α induced an increase in total cellular protein content. Treatment of astrocytes and U373 cells for 72 h with the mitogenic cytokine basic fibroblast growth factor also induced a decrease in glial fibrillary acidic protein content and an increase in total protein level, demonstrating that this effect is not specific for tumor necrosis factor‐α. The decrease in content of glial fibrillary acidic protein detected after tumor necrosis factor‐α treatment is most likely due to dilution by other proteins that are synthesized rapidly in response to cytokine stimulation.