ABSTRACT
Interferon-gamma (IFN-gamma), traditionally associated with a variety of physiological and pathological processes of the immune system, manifests an array of biological effects on cells of the nervous system. Clinical and in vitro studies support a key role for IFN-gamma in the pathogenesis of immune-mediated demyelinating disorders such as multiple sclerosis (MS). To investigate the role of this cytokine within the central nervous system (CNS), transgenic mice were derived in which IFN-gamma transgene expression was selectively targeted to astrocytes, a potentially important cellular source of this cytokine. Here we report that astrocyte-directed expression of IFN-gamma results in regional hypomyelination and selective disruption of brain histogenesis, which included severe cerebellar and hippocampal dysplasia. Transgenic mice were markedly ataxic and the majority died prior to reaching sexual maturity. This study demonstrates that astrocyte-directed expression of IFN-gamma profoundly affects the differentiation and morphogenesis of the brain and provides additional evidence that this cytokine has deleterious consequences on myelin-producing cells, independent of the cellular source.
Subject(s)
Astrocytes/metabolism , Brain/abnormalities , Brain/physiopathology , Demyelinating Autoimmune Diseases, CNS/genetics , Demyelinating Autoimmune Diseases, CNS/physiopathology , Interferon-gamma/genetics , Nerve Fibers, Myelinated/pathology , Animals , Brain/metabolism , Cell Death/genetics , Cerebellum/abnormalities , Cerebellum/metabolism , Cerebellum/physiopathology , Demyelinating Autoimmune Diseases, CNS/metabolism , Genes, Regulator/physiology , Glial Fibrillary Acidic Protein/genetics , Hippocampus/abnormalities , Hippocampus/metabolism , Hippocampus/physiopathology , Interferon-gamma/metabolism , Mice , Mice, Transgenic , Nerve Fibers, Myelinated/metabolism , Tumor Necrosis Factor-alpha/geneticsABSTRACT
Interest in the possible role of herpes simplex virus type 1 (HSV1) as a cofactor in the pathogenesis of Alzheimer's disease (AD) has re-emerged following the detection of viral DNA sequences in the central nervous system (CNS). Evidence from 2 independent laboratories indicates that HSV1 may interact with a host-specific factor, the apolipoprotein E epsilon 4 allele, to further augment the risk for AD. In this review, we consider the arguments implicating HSV1 in the pathogenesis of AD. Although further studies are required to confirm a role for HSV1 in AD and to elucidate its underlying molecular basis, implicating a virus in the pathogenesis of this insidious disease clearly offers novel potential treatments.
