Histone deacetylase-high mobility group box-1 pathway targeted by hypaconitine suppresses the apoptosis of endothelial cells

Hypaconitine is an active component of Aconitum carmichaelii Debx, a Chinese medicinal herb for the treatment of cardiovascular diseases, but the mechanism underlying its effect remains elusive. In this study, we found that hypaconitine, rather than aconitum alkaloids in A. carmichaelii (e.g. aconitine, mesaconitine and benzoylaconitine), prevented endothelial cells from damage due to oxidized low-density lipoprotein (oxLDL) challenge. Cleaved caspase 3 expression in endothelial cells was up-regulated by oxLDL and markedly attenuated by hypaconitine, suggesting that hypaconitine inhibited the oxLDL-induced cell apoptosis. Microarray analysis revealed that histone deacetylase 3 (HDAC3) was significantly increased by hypaconitine. The cytoplasmic relocation and extracellular release of high-mobility group box 1 (HMGB1, an HDAC3 downstream effector) in endothelial cells were significantly increased by oxLDL and markedly decreased by hypaconitine. The effect of hypaconitine on the oxLDL-induced apoptosis and HMGB1 release in endothelial cells was significantly reduced by the suppression of HDAC3 by siRNA or a specific inhibitor. Thus, this study proves that the histone deacetylase-HMGB1 pathway targeted by hypaconitine suppresses the apoptosis of endothelial cells. Our findings are of therapeutic significance and provide the potential of hypaconitine exploitation.