TLR9 and its signaling pathway in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system characterized by axonal destruction and demyelination, which etiology and immunopathogenesis still remains uncertain. Although several lines of evidence show that myelin-reactive T cells play an essential role in the pathogenesis of MS, recent findings have pointed to the relevance of innate immune system such as Toll-like receptors (TLRs). TLRs have been assigned number 1 to 10 in human with different cellular location. Among them, TLR9 is one of the best studied nucleic acid sensing molecules. In this article, we discuss the role of TLR9 and its signaling pathway in the development of MS and present some therapeutic strategies based on in vivo and in vitro findings.