Open AccessNeuroinflammation in the normal-appearing white matter (NAWM) of the multiple sclerosis brain causes abnormalities at the nodes of Ranvier
Author(s) -
Patricia Gallego-Delgado,
Rachel James,
Eleanor Browne,
Joanna Meng,
Swetha Umashankar,
Li Yi Tan,
Carmen Picón,
Nicholas D. Mazarakis,
A. Aldo Faisal,
Owain W. Howell,
Richard Reynolds
Publication year - 2020
Publication title -
plos biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.127
H-Index - 271
eISSN - 1545-7885
pISSN - 1544-9173
DOI - 10.1371/journal.pbio.3001008
Subject(s) - white matter , multiple sclerosis , biology , glutamate receptor , neuroinflammation , inflammation , axon , pathology , neuroscience , microglia , nerve conduction velocity , immunology , receptor , medicine , magnetic resonance imaging , biochemistry , radiology
Changes to the structure of nodes of Ranvier in the normal-appearing white matter (NAWM) of multiple sclerosis (MS) brains are associated with chronic inflammation. We show that the paranodal domains in MS NAWM are longer on average than control, with Kv1.2 channels dislocated into the paranode. These pathological features are reproduced in a model of chronic meningeal inflammation generated by the injection of lentiviral vectors for the lymphotoxin-α (LTα) and interferon-γ (IFNγ) genes. We show that tumour necrosis factor (TNF), IFNγ, and glutamate can provoke paranodal elongation in cerebellar slice cultures, which could be reversed by an N-methyl-D-aspartate (NMDA) receptor blocker. When these changes were inserted into a computational model to simulate axonal conduction, a rapid decrease in velocity was observed, reaching conduction failure in small diameter axons. We suggest that glial cells activated by pro-inflammatory cytokines can produce high levels of glutamate, which triggers paranodal pathology, contributing to axonal damage and conduction deficits.