J Hypertens. 2014 Feb;32(2):306-17. doi: 10.1097/HJH.0000000000000018.

Enhanced activation of NAD(P)H: quinone oxidoreductase 1 attenuates spontaneous hypertension by improvement of endothelial nitric oxide synthase coupling via tumor suppressor kinase liver kinase B1/adenosine 5'-monophosphate-activated protein kinase-mediated guanosine 5'-triphosphate cyclohydrolase 1 preservation.

Kim YH¹, Hwang JH, Kim KS, Noh JR, Gang GT, Oh WK, Jeong KH, Kwak TH, Choi HS, Lee IK, Lee CH.

Author information

1: aLaboratory Animal Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon bKorea Bioactive Natural Material Bank, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul cDiabetes and Metabolic Disease Research Center, Lee Gil Ya Cancer & Diabetes Institute, Gachon University of Medicine, Incheon dKT&G Life Sciences Corporation/R&D Center, Suwon eHormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju fDepartment of Internal Medicine, Kyungpook National University School of Medicine, Daegu, South Korea.

Abstract

AIMS:

Guanosine 5'-triphosphate cyclohydrolase-1 (GTPCH-1) is a rate-limiting enzyme in de-novo synthesis of tetrahydrobiopterin (BH4), an essential cofactor for endothelial nitric oxide synthase (eNOS) coupling. Adenosine 5'-monophosphate-activated protein kinase (AMPK) is crucial for GTPCH-1 preservation, and tumor suppressor kinase liver kinase B1 (LKB1), an upstream kinase of AMPK, is activated by NAD-dependent class III histone deacetylase sirtuin 1 (SIRT1)-mediated deacetylation. β-Lapachone has been shown to increase cellular NAD/NADH ratio via

NAD(P)H:

quinone oxidoreductase 1 (NQO1) activation. In this study, we have evaluated whether β-lapachone-induced NQO1 activation modulates blood pressure (BP) through preservation of GTPCH-1 in a hypertensive animal model.

METHODS AND RESULTS:

Spontaneously hypertensive rats (SHRs), primary aortic endothelial cells, and endothelial cell line were used to investigate the hypotensive effect of β-lapachone and its action mechanism. β-Lapachone treatment dramatically lowered BP and vascular tension in SHRs and induced eNOS activation in endothelial cells. Consistent with these effects, β-lapachone treatment also elevated levels of both aortic cGMP and plasma nitric oxide in SHRs. Meanwhile, β-lapachone-treated SHRs showed significantly increased levels of aortic NAD, LKB1 deacetylation, and AMPK Thr phosphorylation followed by increased GTPCH-1 and tetrahydrobiopterin/dihydrobiopterin ratio. In-vitro study revealed that AMPK inhibition by overexpression of dominant-negative AMPK nearly abolished GTPCH-1 protein conservation. Enhanced LKB1 deacetylation and AMPK activation were also elicited by β-lapachone in endothelial cells. However, inhibition of LKB1 deacetylation by blocking of NQO1 or SIRT1 blunted AMPK activation by β-lapachone.

CONCLUSION:

This is the first study demonstrating that eNOS coupling can be regulated by NQO1 activation via LKB1/AMPK/GTPCH-1 modulation, which is possibly correlated with relieving hypertension. These findings provide strong evidence to suggest that NQO1 might be a new therapeutic target for hypertension.