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Figure 1. Effects of HMGB1 stimulation on human SMCs. A) Human SMCs migrate in response to HMGB1. SMCs were subjected to chemotaxis assays with 30 ng/ml HMGB1, 10 ng/ml PDGFBB, or 10% FCS. Data are average ± SD of 4 experiments performed in duplicate; effect of HMGB1 is highly significant (P<0.001) compared with control. Migration of human SMCs was abrogated by antibodies against HMGB1 or receptor for advanced glycation end-products (P<0.001) compared with HMGB1 alone. B) Human aorta SMCs proliferate in response to HMGB1. Cells were grown in F12K medium alone, or containing 30 ng/ml of HMGB1, or 10% FCS. HMGB1 induced cell proliferation, and SMCs in medium alone died. Each point is mean ± SD of 3 experiments in duplicate, and result is highly statistically significant (P<0.001). C) Human SMCs secrete HMGB1 after stimulation with HMGB1. Subconfluent SMCs were starved for 16 h and exposed for 48 h to a fragment of HMGB1 (Box B) that retains properties of full-length HMGB1 but is not recognized by the monoclonal antibody used here for HMGB1 detection. The absence of LDH in supernatant indicates that HMGB1 is secreted and not released by necrotic cells.
