Glial fibrillary acidic protein expression alters astrocytic chemokine release and protects mice from cuprizone-induced demyelination.

Enhanced glial fibrillary acidic protein (GFAP) expression occurs in most diseases of the central nervous system. Thus far, little is known about the effect that GFAP exerts on astrocyte cell signaling. In the present study, we observed that silencing GFAP expression in isolated astrocytes leads to enhanced CCL2 and CXCL10 release, whereas overexpression of GFAP in astrocytes results in a significantly reduced CXCL10 release in vitro. Additionally, we analyzed transgenic mice carrying a full-length copy of the wild-type human GFAP gene. We demonstrate that a persistent GFAP increase alters the astrocytic cell signaling profile, thereby protecting oligodendrocytes, myelin and, subsequently, axons from cuprizone-induced demyelination. Our study revealed that reduced CXCL10 mRNA was accompanied by reduced NF-κB expression in astrocytes. Furthermore, analysis of human tissue from a patient with Alexander disease showed NF-κB activation in astrocytes to be almost completely absent. Our findings indicate that regulation of GFAP expression in astrocytes is crucial for astrocyte signaling and function. Understanding the role of the cytoskeletal protein, GFAP is thus of importance as it is highly regulated in diseases of the central nervous system.