The Small GTPases Regulate HMC05-Induced NQO-1 Expression with an Antioxidant Effect in Smooth Muscle Cells

Recently, Banhabackchulchunmatang (HMC05) has been implicated as a preventive and/or therapeutic candidate for cardiovascular diseases due to its inhibition of atherosclerosis lesions and its reduction of neointima formation. Knowledge of the mechanism of HMC05 in smooth muscle cells (SMC) is limited. However, SMC may be a potential target for HMC05 therapy because they are supported by the HMC05-mediated preservation of medial smooth muscle cell layers in pathogenic progression. Therefore, in the present study, we hypothesized that the effect of HMC05 is associated with reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H):quinone oxidoreductase-1 (NQO-1) gene regulation, which precipitates an antioxidant effect in SMC. HMC05 significantly increased NQO-1 gene expression in a dose- and time-dependent manner. The reactive oxygen species-mediated toxicity that was generated by xanthine/xanthine oxidase was suppressed by HMC05. The knockdown of the NQO-1 gene abrogated the HMC05-mediated cytoprotection. Interestingly, pretreatment with a chemical inhibitor of geranylgeranyl transferase 1 or farnesyl transferase abolished the NQO-1 gene induction and cytoprotection by HMC05. The transfection of dominant negative RhoA or Ras suppressed HMC05-induced gene expression. Berberine and hesperidin, which are found in large quantities in HMC05, also induced NQO-1 gene expression. Taken together, this is the first study to demonstrate that HMC05 is efficacious in protection against oxidative stress through NOQ-1 gene induction via the regulation of RhoA and/or Ras, and that berberine and hesperidin are major components of NQO-1 gene induction. This study provides mechanistic targets of HMC05 in reducing atherosclerotic lesions in atherosclerosis.