HMGB1 and amyotrophic lateral sclerosis: To determine whether extracellular HMGB1 can act on neighboring ALS astroglia, we exposed primary spinal cord astrocytes from non-Tg, SOD1WT or SOD1G93A mice to exogenous disulfide-HMGB1 (3 μg/ml, 6 h), so as to mimic paracrine actions of the potentially secreted protein.