Young-Won Seo

NAD(P)H:quinone oxidoreductase 1 activation reduces blood pressure through regulation of endothelial nitric oxide synthase acetylation in spontaneously hypertensive rats.

BACKGROUND Endothelial nitric oxide synthase (eNOS) is involved in blood pressure (BP) regulation through the production of nitric oxide. Sirtuin I (SIRT1), an NAD-dependent protein deacetylase, promotes vascular relaxation through deacetylation and activation of eNOS. β-Lapachone (βL) increases the cellular NAD(+)/NADH ratio by activating NAD(P)H quinone oxidoreductase 1 (NQO1). In this study, we verified whether activation of NQO1 by βL modulates BP through regulation of eNOS acetylation in a hypertensive animal model. METHODS Spontaneously hypertensive rats (SHRs) and an endothelial cell line (bEnd.3 cells) were used to investigate the hypotensive effect of βL and its mechanism of action. RESULTS βL treatment significantly lowered the BP in SHRs, but this hypotensive effect was completely blocked by eNOS inhibition with ω-nitro-l-arginine methyl ester. In vitro studies revealed that βL activated eNOS, which was accompanied by an increased NAD(+)/NADH ratio. Moreover, βL significantly decreased acetylation of eNOS; however, this reduced eNOS acetylation was completely precluded by inhibition of SIRT1 in the bEnd.3 cells and in the aorta of the SHRs. Consistent with these effects, βL-induced reduction in BP was also abolished by SIRT1 inhibition in the SHRs. CONCLUSIONS To the best of our knowledge, this is the first study to demonstrate that eNOS acetylation can be regulated by NQO1 activation in an SIRT1-dependent manner, which is correlated with the relief of hypertension. These findings provide strong evidence that NQO1 might be a new therapeutic target for hypertension.

Quisqualis indica Improves Benign Prostatic Hyperplasia by Regulating Prostate Cell Proliferation and Apoptosis

Quisqualis indica (QI) has been used for treating disorders such as stomach pain, constipation, and digestion problem. This study was aimed to evaluate the therapeutic efficacy of QI extract on treating benign prostatic hyperplasia (BPH) in LNCaP human prostate cancer cell line and a testosterone-induced BPH rat model. LNCaP cells were treated with QI plus testosterone propionate (TP), and androgen receptor (AR) and prostate specific antigen (PSA) expression levels were assessed by Western blotting. To induce BPH, the rats were subjected to a daily subcutaneous injection of TP (3 mg/kg) for 4 weeks. The rats in treatment group were orally gavaged with QI (150 mg/kg) together with the TP injection. In-vitro studies showed that TP-induced increases in AR and PSA expression in LNCaP cells were reduced by QI treatment. In BPH-model rats, the prostate weight, testosterone in serum, dihydrotestosterone (DHT) concentration and 5α-reductase type 2 mRNA expression in prostate tissue were significantly reduced following the treatment with QI. TP-induced prostatic hyperplasia and the expression of proliferating cell nuclear antigen (PCNA) and cyclin D1 were significantly attenuated in QI-treated rats. In addition, QI induced apoptosis by up-regulating caspase-3 and -9 activity and decreasing the B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) ratio in prostate tissues of BPH rats. Further investigation showed that TP-induced activation of AKT and glycogen synthase kinase 3β (GSK3β) was reduced by QI administration. Therefore, our findings suggest that QI attenuates the BPH state in rats through anti-proliferative and pro-apoptotic activities and might be useful in the clinical treatment of BPH.