Extracellular release of high mobility group box 1 (HMGB1) from F11 neuronal cell line. (A) Western blot analysis of extracellular supernatant of HMGB1 after a 1 hour exposure to 50 K, ionomycin (20 μM) and a balanced sterile solution (BSS) of F11 differentiated cells. (B) Representative image of F11 differentiated cells. (C, C1) HMGB1 is confined in the nucleus of F11 differentiated neuronal cell line in the BSS control sample (arrows). (D, D1) HMGB1 protein relocates into the cytoplasm following a 1 hour exposure (arrows). Scale bar 50 μm.