HMGB1 expression patterns during the progression of experimental autoimmune encephalomyelitis.

High mobility group box 1 (HMGB1), a nonhistone chromatin associated protein, plays different roles according to the expression pattern such as the amount, cell location and sub-cellular location. It has been recently demonstrated that the systemic HMGB1 is associated with autoimmune encephalomyelitis. However, the dynamic change of HMGB1 expression pattern in spinal cords that may be involved in the progression of disease is not fully understood. In this study, the amount, cell location and subcellular location of HMGB1 in adult mice spinal cords during various stages of experimental autoimmune encephalomyelitis (EAE) are investigated. HMGB1 is expressed in the nuclei of spinal cord resident cells such as some astrocytes, microglia and a few neurons in normal situation. During EAE progression, the total and extracellular HMGB1 in the spinal cord are increased, more HMGB1 positive astrocytes and microglia are observed, and the intra-neurons HMGB1 in the ventral horn and around the central canal localize majorly in the cytoplasm accompanied by the increasing extracellular HMGB1. Blockade of HMGB1 in central nervous system (CNS) locally attenuates the severity of EAE significantly. Our findings indicate that the HMGB1 expression pattern in the spinal cord is associated with the progression of EAE. HMGB1 may be a potential target for autoimmune encephalomyelitis (multiple sclerosis in human) therapy.