Homocysteine regulates endothelin type B receptors in vascular smooth muscle cells.
Vascular smooth muscle endothelin type B (ETB) receptor is involved in the pathogenesis of cardiovascular diseases (CVDs). Hyperhomocysteinemia is an independent risk factor for CVDs. The present study was designed to examine the hypothesis that homocysteine (Hcy) up-regulates vascular smooth muscle ETBreceptors. In vitro experiments were performed in rat superior mesenteric artery (SMA) and vascular smooth muscle cells (VSMCs). The rat SMA or VSMCs were cultured in serum-free medium for 24h in the presence and absence of Hcy with or without specific inhibitors for the ERK1/2 signaling pathway and NF-κB. In vivo, the rats received subcutaneous injections of Hcy in the presence or absence of specific inhibitors for the ERK1/2 signaling pathway (U0126) for 3weeks. Levels of protein expression were determined using Western blot analysis. The contractile responses to sarafotoxin 6c (an ETBreceptor agonist) were studied using a sensitive myograph. The blood pressure of the rats was measured via a noninvasive tail-cuff plethysmography method. The results from in vitro experiments showed that Hcy concentration-dependently increased the ETBreceptor-mediated contractile responses, and up-regulated ETBreceptor expression, in rat SMA. Blockage of the ERK1/2 signaling pathway and NF-κB using the MEK1/2 inhibitor (PD98059 and U0126) or IκB kinase inhibitor (wedelolactone) significantly abolished Hcy-induced up-regulation of ETBreceptor. Finally, we used VSMCs as a cellular model to further validate our finding. In vivo study found that hyperhomocysteinemia up-regulated ETBreceptor expression, and elevated the blood pressure of rats via the ERK1/2 signaling pathway. In conclusion, Hcy up-regulated vascular smooth muscle ETBreceptor via activation of the ERK1/2 signaling pathway and NF-κB.
Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi 710021, China; Shaanxi Pharmaceutical Development Center, Shaanxi Pharmaceutical Holding Group Co., LTD, Xi'an, Shaanxi 710075, China. Electronic address: chenyulong.0901@stu.xjtu.edu.cn.
Yulong
Y
Chen
The First Affiliated Hospital of Xi'an Medical University, Xi'an Medical University, Xi'an, Shaanxi 710077, China.
Hongmei
H
Zhang
Laboratory Animal Center, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, China.
Enqi
E
Liu
Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi 710021, China; Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, BMC A13, SE-221 84 Lund, Sweden.
Cang-Bao
CB
Xu
Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi 710021, China.
Yaping
Y
Zhang
D000818:Animals; D001794:Blood Pressure; D015153:Blotting, Western; D006710:Homocysteine / Q000378:metabolism*; D020138:Hyperhomocysteinemia / Q000150:complications*; D020935:MAP Kinase Signaling System; D008297:Male; D017538:Mesenteric Artery, Superior / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D010991:Plethysmography / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D044023:Receptor, Endothelin B / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D014757:Viper Venoms / Q000494:pharmacology
D016328:NF-kappa B; D044023:Receptor, Endothelin B; D014757:Viper Venoms; C057354:sarafotoxins s6; D006710:Homocysteine
ERK1/2; Endothelin type B receptor; Homocysteine; Hyperhomocysteinemia; NF-κB