Date Published: July 10, 2017
Publisher: Public Library of Science
Author(s): Ni-Hsuan Lin, Albee Messing, Ming-Der Perng, Pavel Strnad.
Alexander disease (AxD) is a neurodegenerative disease caused by heterozygous mutations in the GFAP gene, which encodes the major intermediate filament protein of astrocytes. This disease is characterized by the accumulation of cytoplasmic protein aggregates, known as Rosenthal fibers. Antibodies specific to GFAP could provide invaluable tools to facilitate studies of the normal biology of GFAP and to elucidate the pathologic role of this IF protein in disease. While a large number of antibodies to GFAP are available, few if any of them have defined epitopes. Here we described the characterization of a panel of commonly used anti-GFAP antibodies, which recognized epitopes at regions extending across the rod domain of GFAP. We show that all of the antibodies are useful for immunoblotting and immunostaining, and identify a subset that preferentially recognized human GFAP. Using these antibodies, we demonstrate the presence of biochemically modified forms of GFAP in brains of human AxD patients and mouse AxD models. These data suggest that this panel of anti-GFAP antibodies will be useful for studies of animal and cell-based models of AxD and related diseases in which cytoskeletal defects associated with GFAP modifications occur.
Intermediate filaments (IFs) are a highly dynamic cytoskeletal component that provides a structural scaffold and a signaling platform for the organization of the cytoplasm. In humans, at least 70 different IF proteins have been identified , many of which are expressed in cell type specific patterns. In astrocytes, GFAP, together with lesser amounts of vimentin , nestin , and synemin , are the major IF proteins that constitute the glial filaments.