Voltage-gated potassium channels in multiple sclerosis: Overview and new implications for treatment of central nervous system inflammation and degeneration.

Inflammatory tissue damage and the presence of reactive immunocompetent T lymphocytes, macrophages, microglia, and dendritic cells (DCs) are characteristic features in the human chronic inflammatory demyelinating disease, multiple sclerosis (MS). Together, these cells orchestrate the inflammation and immunopathogenesis underlying the MS autoimmune disease processes and all up-regulate the same voltage-gated potassium (K(v)) channel, K(v)1.3, when fully activated. Only microglia, which mediate central nervous system (CNS) inflammatory processes (possibly playing a dual role of CNS protection and mediation of neuroinflammation/ neurodegeneration), and DC, which are pivotal to the induction of T cell responses, express the distinct K(v)1.5 prior to K(v)1.3 up-regulation. Although the precise functional roles of first K(v)1.5 and then K(v)1.3 channels are unclear, their differential expression is likely a common mechanism used by both microglia and DC, revealing K(v)1.5 (in addition to K(v)1.3) as a potentially important target for the development of new immunomodulatory therapies in MS.