Jia-Xiang Chen1, Kun-Yue Xue1, Juan-Juan Xin1, Xin Yan2, Ru-Li Li1, Xiao-Xiao Wang1, Xu-Lei Wang3, Ming-Ming Tong1, Lu Gan1, He Li1, Jie Lan1, Xue Li1, Cai-Li Zhuo1, Ling-Yu Li1, Zi-Jie Deng1, Heng-Yu Zhang4, Wei Jiang5. 1. Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China. 2. Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China; Department of Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China. 3. Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China; School of Life Sciences and Bioengineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, PR China. 4. Department of Cardiology, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, PR China. 5. Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China. Electronic address: wcumsjw@scu.edu.cn.
Abstract
BACKGROUND: Abnormalities of the L-arginine-nitric oxide pathway induce hypertension. 5-Lipoxygenase (5-LO) is the key enzyme involved in synthesis of leukotrienes (LTs). However, whether nitricoxide synthase dysfunction induces hypertensive vascular remodeling by regulating 5-LO activity and its downstream inflammatory metabolites remains unknown. METHODS AND RESULTS: Six-week L-NAME treatment significantly induced hypertension and vascular remodeling in both wild-type (WT) and 5-LO-knockout (5-LO-KO) mice, and blood pressure in caudal and carotid arteries was lower in 5-LO-KO than WT mice with L-NAME exposure. On histology, L-NAME induced less media thickness, media-to-lumen ratio, and collagen deposition and fewer Ki-67-positive vascular smooth muscle cells (VSMCs) but more elastin expression in thoracic and mesenteric aortas of 5-LO-KO than L-NAME-treated WT mice. L-NAME significantly increased LT content, including LTB4 and cysteinyl LT (CysLTs), in plasma and neutrophil culture supernatants from WT mice. On immunohistochemistry, L-NAME promoted the colocalization of 5-LO and 5-LO-activating protein on the nuclear envelope of cultured neutrophils, which was accompanied by elevated LT content in culture supernatants. In addition, LTs significantly promoted BrdU incorporation, migration and phenotypic modulation in VSMCs. CONCLUSION: L-NAME may activate the 5-LO/LT pathway in immune cells, such as neutrophils, and promote the products of 5-LO metabolites, including LTB4 and CysLTs, which aggravate vascular remodeling in hypertension. 5-LO deficiency may protect against hypertension and vascular remodeling by reducing levels of 5-LO downstream inflammatory metabolites.
BACKGROUND: Abnormalities of the L-arginine-nitric oxide pathway induce hypertension. 5-Lipoxygenase (5-LO) is the key enzyme involved in synthesis of leukotrienes (LTs). However, whether nitricoxide synthase dysfunction induces hypertensive vascular remodeling by regulating 5-LO activity and its downstream inflammatory metabolites remains unknown. METHODS AND RESULTS: Six-week L-NAME treatment significantly induced hypertension and vascular remodeling in both wild-type (WT) and 5-LO-knockout (5-LO-KO) mice, and blood pressure in caudal and carotid arteries was lower in 5-LO-KO than WT mice with L-NAME exposure. On histology, L-NAME induced less media thickness, media-to-lumen ratio, and collagen deposition and fewer Ki-67-positive vascular smooth muscle cells (VSMCs) but more elastin expression in thoracic and mesenteric aortas of 5-LO-KO than L-NAME-treated WT mice. L-NAME significantly increased LT content, including LTB4 and cysteinyl LT (CysLTs), in plasma and neutrophil culture supernatants from WT mice. On immunohistochemistry, L-NAME promoted the colocalization of 5-LO and 5-LO-activating protein on the nuclear envelope of cultured neutrophils, which was accompanied by elevated LT content in culture supernatants. In addition, LTs significantly promoted BrdU incorporation, migration and phenotypic modulation in VSMCs. CONCLUSION:L-NAME may activate the 5-LO/LT pathway in immune cells, such as neutrophils, and promote the products of 5-LO metabolites, including LTB4 and CysLTs, which aggravate vascular remodeling in hypertension. 5-LO deficiency may protect against hypertension and vascular remodeling by reducing levels of 5-LO downstream inflammatory metabolites.