Article abstract
Nature Immunology 8, 74 - 83 (2006)
Published online: 3 December 2006 | doi:10.1038/ni1415
Osteopontin-induced relapse and progression of autoimmune brain disease through enhanced survival of activated T cells
Eun Mi Hur1,2, Sawsan Youssef2, M Edward Haws2, Susan Y Zhang2, Raymond A Sobel3 & Lawrence Steinman1,2
Abstract
Relapses and disease exacerbations are vexing features of multiple sclerosis. Osteopontin (Opn), which is expressed in multiple sclerosis lesions, is increased in patients' plasma during relapses. Here, in models of multiple sclerosis including relapsing, progressive and multifocal experimental autoimmune encephalomyelitis (EAE), Opn triggered recurrent relapses, promoted worsening paralysis and induced neurological deficits, including optic neuritis. Increased inflammation followed Opn administration, whereas its absence resulted in more cell death of brain-infiltrating lymphocytes. Opn promoted the survival of activated T cells by inhibiting the transcription factor Foxo3a, by activating the transcription factor NF-
B through induction of phosphorylation of the kinase IKK
and by altering expression of the proapoptotic proteins Bim, Bak and Bax. Those mechanisms collectively suppressed the death of myelin-reactive T cells, linking Opn to the relapses and insidious progression characterizing multiple sclerosis.
- Interdepartmental Program in Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California 94305, USA.
- Department of Pathology (Neuropathology), Stanford University School of Medicine, Stanford, California 94305, USA.
Correspondence to: Lawrence Steinman1,2 e-mail: steinman@stanford.edu
