Metformin inhibited homocysteine-induced upregulation of endothelin receptors through the Sirt1/NF-κB signaling pathway in vascular smooth muscle cells

Yulong Chen; Xingli Su; Qiaohong Qin; Yue Yu; Min Jia; Lingheng Kong; Hongmei Zhang; Huijin Li

doi:10.1016/j.vph.2019.106613

Metformin inhibited homocysteine-induced upregulation of endothelin receptors through the Sirt1/NF-κB signaling pathway in vascular smooth muscle cells

Vascul Pharmacol. 2020 Jan:124:106613. doi: 10.1016/j.vph.2019.106613. Epub 2019 Oct 31.

Authors

Yulong Chen¹, Xingli Su², Qiaohong Qin³, Yue Yu³, Min Jia⁴, Lingheng Kong⁵, Hongmei Zhang⁶, Huijin Li³

Affiliations

¹ Institute of Basic and Translational Medicine, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Shaanxi Key Laboratory of Brain Disorders, Xi'an Medical University, Xi'an, Shaanxi 710021, China; School of Basic and Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi 710021, China. Electronic address: chenyulong.0901@stu.xjtu.edu.cn.
² School of Basic and Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi 710021, China. Electronic address: suxingli@xiyi.edu.cn.
³ Institute of Basic and Translational Medicine, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Shaanxi Key Laboratory of Brain Disorders, Xi'an Medical University, Xi'an, Shaanxi 710021, China.
⁴ Institute of Basic and Translational Medicine, Shaanxi Key Laboratory of Ischemic Cardiovascular Disease, Shaanxi Key Laboratory of Brain Disorders, Xi'an Medical University, Xi'an, Shaanxi 710021, China; School of Basic and Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi 710021, China.
⁵ School of Basic and Medical Sciences, Xi'an Medical University, Xi'an, Shaanxi 710021, China.
⁶ The First Affiliated Hospital of Xi'an Medical University, Xi'an Medical University, Xi'an, Shaanxi 710077, China.

PMID: 31678650
DOI: 10.1016/j.vph.2019.106613

Abstract

Metformin (Met) can improve atherosclerosis (As). Abnormal endothelin receptors [including endothelin type A (ET_A) or type B (ET_B) receptor] in vascular smooth muscle cells (VSMCs) are involved in As. Hyperhomocysteinemia (HHcy) is an independent risk factor for As. The present study was designed to test our hypothesis that Met inhibits the upregulation of endothelin receptors induced by homocysteine (Hcy) in VSMCs. Rat superior mesenteric artery (SMA) without endothelium, as an in vitro model, was cultured in serum-free medium for 24 h in the presence of Hcy with or without Met or nicotinamide (Nic). In vivo, rats received subcutaneous injections of Hcy in the presence or absence of Met or Nic for 3 weeks. Levels of protein expression were determined by Western blotting. The contractile responses to sarafotoxin 6c (an ET_B receptor agonist) or ET-1 (an ET_A/ ET_B receptor agonist) were studied using a sensitive myograph. The blood pressure of rats was measured using a noninvasive tail-cuff plethysmography method. The results showed that Met could significantly inhibit the Hcy-induced upregulation of endothelin receptors (including ET_A and ET_B receptor) protein expression and endothelin receptor-mediated vasoconstriction, and it recovered the Hcy-induced decrease in silent information regulator 1 (Sirt1) in a dosage-dependent manner in SMA. However, Nic (a Sirt1 inhibitor) recovered the levels of Met-inhibited endothelin receptors and acetylated p65. Furthermore, the in vivo results showed that Met not only significantly the inhibited HHcy-induced upregulation of endothelin receptors and acetylated p65 but also recovered the HHcy-induced decrease in Sirt1 in a dosage-dependent manner in SMA. In addition, Met significantly inhibited the HHcy-induced blood pressure elevation. However, these effects were reverted by Nic. In conclusion, these data demonstrated that Met inhibited the Hcy-induced increase in endothelin receptor expression by activating Sirt1 and then inhibiting NF-κB in VSMCs. These findings may provide insights into the mechanism underlying of Met-treated cardiovascular diseases induced by Hcy.

Keywords: Endothelin receptors; Homocysteine; Metformin; Sirt1.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Blood Pressure / drug effects*
Cells, Cultured
Homocysteine / toxicity*
Male
Mesenteric Artery, Superior / drug effects
Mesenteric Artery, Superior / enzymology
Metformin / pharmacology*
Muscle, Smooth, Vascular / drug effects*
Muscle, Smooth, Vascular / enzymology
Myocytes, Smooth Muscle / drug effects*
Myocytes, Smooth Muscle / enzymology
NF-kappa B / metabolism*
Rats, Sprague-Dawley
Receptors, Endothelin / metabolism*
Signal Transduction
Sirtuin 1 / metabolism*
Up-Regulation
Vasoconstriction / drug effects*

Substances

NF-kappa B
Receptors, Endothelin
Homocysteine
Metformin
Sirt1 protein, mouse
Sirtuin 1