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Transient 5‐(4‐phenylbutoxy)psoralen (PAP‐1) treatment dissociates developing pathologies in autoimmune optic neuritis into two distinct pathology profiles
Author(s) -
Stokely Martha E.,
Garg Puja,
Bhat Manzoor A.,
Koulen Peter
Publication year - 2008
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21645
Subject(s) - optic neuritis , myelin oligodendrocyte glycoprotein , multiple sclerosis , axon , myelin , medicine , neuroinflammation , pathology , autoimmunity , immunology , inflammation , optic nerve , oligodendrocyte , immune system , central nervous system , experimental autoimmune encephalomyelitis , anatomy
Abstract Discovery of treatments to protect axonal function of neurons and prevent permanent disability associated with progressive multiple sclerosis (MS) has faced the uphill challenge of assessing relatively small changes in accumulated axon damage within a background environment that is disorganized by CNS inflammation. We hypothesized that transient immunosuppression after initiation of MS‐like autoimmune mechanisms would disassociate development of MS‐like myelinated axon pathology from development of CNS inflammation in a rat model of autoimmune optic neuritis (AON). A rat model of myelin oligodendrocyte glycoprotein peptide‐induced AON was transiently treated (on days 3–7 after antigen exposure) with 5‐(4‐phenylbutoxy)psoralen (PAP‐1), an immunomodulatory drug previously shown specifically to suppress proliferation of effector memory T‐cells and immunoglobulin class‐switched B‐cells. Thirteen days after antigen exposure, optic nerves were harvested for quantitative assessment of 12 MS‐associated pathologies using microfluorimetry. With one exception, the immunoreactivities (‐ir) for eight markers of MS‐like neuroinflammation and immune infiltration were significantly reduced ( P < 0.05) by transient PAP‐1 treatment, often to levels significantly below those detected in normal control rat optic nerves. With one exception, four immunoreactive markers of MS‐like myelinated axon pathology were detected at levels indicating increased axon/myelin pathology compared with vehicle‐treated rats with AON ( P < 0.05). These data suggest the conclusion that early causative mechanisms in CNS autoimmunity initiate signaling mechanisms that diverge into two separate pathways, one that is strongly associated with inflammatory responses and one that is associated predominantly with disturbed axon‐myelin interactions and impaired fast axonal transport. © 2008 Wiley‐Liss, Inc.