Broad Expression of Toll-Like Receptors in the Human Central Nervous System

The family of Toll-like receptors (TLRs) plays a key role in controlling innate immune responses to a wide variety of pathogen-associated molecules. In this study we investigated expression of TLRs in vitro by purified human microglia, astrocytes, and oligodendrocytes, and in vivo by immunohistochemical examination of brain and spinal cord sections. Cultured primary microglia were found to express mRNA encoding a wide range of different TLR family members while astrocytes and oligodendrocytes primarily express TLR2 and TLR3. Comparisons between microglia derived from a series of control subjects and neurodegenerative cases indicate distinct differences in levels of mRNA encoding the different TLRs indifferent…