Montelukast, cysteinyl leukotriene receptor 1 antagonist, inhibits cardiac fibrosis by activating APJ

Abstract

Montelukast, cysteinyl leukotriene receptor 1 (CysLT1R) antagonist, is used clinically for patients with asthma, chronic obstructive pulmonary diseases (COPD), and allergic rhinitis. It has been reported that CysLT1R antagonists could reduce the risks of cardiovascular diseases in animal studies. Cardiac fibrosis is one of the major causes of heart failure. But little is known about the role of Montelukast in cardiac fibrosis and its underlying mechanism. In transverse aortic constriction (TAC) mice, Montelukast improved cardiac pumping function and inhibited cardiac fibrosis by down-regulation of the proteins related to the fibrosis, such as connective tissue growth factor (CTGF), Transforming Growth Factor β (TGF-β), and Alpha-smooth muscle actin (α-SMA). Montelukast reduced cell proliferation and collagen production in neonatal cardiac fibroblasts (CFs) with the pretreatment of 20% serum, while down-regulating the expression of TGF-β, CTGF and α-SMA. Molecules docking methods estimated a high affinity of Montelukast to Apelin receptor (APJ) and an effective chemical structure for Montelukast binding APJ. In Chinese hamster ovary (CHO) cells with stable overexpressing APJ, Montelukast inhibited forskolin (1 μM)-mediated cyclic adenosine monophosphate (cAMP) production and extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation, while these effects were reversed by pertussis toxin (PTX) pretreatment. APJ silence disrupted the effects of Montelukast in CFs pretreatment by serum 20%. So we concluded that Montelukast inhibited cardiac fibrosis due presumably to the coupling to the APJ-mediated Gi signaling pathway, which may be a promising therapeutic target for cardiac fibrosis.

Introduction

Cysteinyl leukotrienes (CysLTs) are a class of inflammatory mediator which is the products of arachidonic acid metabolism via the 5-lipoxygenase pathway (Henderson et al., 2006; Prescott et al., 2020). Montelukast, a cysteinyl leukotriene receptor 1 (CysLT1R) antagonist, is mainly used for the prevention and long-term treatment of asthma in a clinic, to prevent exercise-induced bronchoconstriction, and also for relieving allergic rhinitis (Muz et al., 2006; Rubinstein et al., 2004). Montelukast has also been applied for patients with cystic fibrosis to reduce airway cysteinyl leukotriene levels, which may contribute to airway inflammation (Peng et al., 2017; Shimbori et al., 2011; Spencer et al., 1992). Montelukast inhibits the oxidant-induced tissue fibrosis via balancing oxidant-antioxidant status and regulating the generation of pro-inflammatory mediators (Schmitt-Grohe et al., 2002; Sener et al., 2007). Therefore, we have a strong reason to believe that the anti-fibrosis effects of Montelukast are mainly due at least partially to interrupt inflammatory processes, rather than to directly antagonize its receptor, CysLT1R. Montelukast-mediated regulation of inflammatory responses includes inhibition of the enzymes 5-lipoxygenase (Ramires et al., 2004), histone acetyltransferase (HAT) (Tahan et al., 2008), and cAMP phosphodiesterase (Anderson et al., 2009), as well as inhibition of eosinophil adhesion to vascular endothelium and migration (Robinson et al., 2008). However, little is known about the effect of Montelukast on heart diseases, especially cardiac fibrosis, or the mechanisms underlying this process.

Apelin receptor (APJ) has strong homology with angiotensin II (Ang II) type 1 receptor (AT1R) (transmembrane domain is 54% and the entire sequence is 30%) (Cayabyab et al., 2000; Tatemoto et al., 1998). Apelin, the endogenous ligand of APJ, is an important protective regulator by binding and activating APJ, which is an exactly opposite effect by binding to AT1R. Apelin/APJ system has a wide tissue distribution in the heart as well as in other organs or tissue including the brain, lung, vessels, and adipose tissue (Koguchi et al., 2012; Zhong et al., 2017). Apelin/APJ system plays diverse roles in cardiovascular system, such as enhancing cardiac contractility, inhibiting cardiomyocyte hypertrophy, inhibiting atherosclerosis and cardiac fibrosis (Parikh et al., 2018; Zhang et al., 2016). Apelin significantly reduces Ang II-induced cardiac hypertrophy by reducing the cell size and protein content of cardiomyocytes (Zhang et al., 2017). Apelin eliminates Ang II-induced cardiovascular fibrosis by inhibiting PAI-1 (Siddiquee et al., 2011). Our previous studies have shown that Apelin-13 inhibits Ang II-induced fibrosis through a TGFβ-CTGF-dependent mechanism (Zhou et al., 2016). Apelin/APJ constitutes a novel endogenous peptide/GPCR system and promises as an anti-fibrotic target for the development of novel therapeutic agents.

Molecular docking methods have broadly been used in modern drug design and to explore the ligand conformations adopted within the binding sites of macromolecular targets (Fang, 2012; Wilson and Lill, 2011). Using this approach, a higher affinity and an effective chemical structure of Montelukast for binding to APJ have been estimated in the current study. Therefore, we investigated the regulatory effect of Montelukast and the mechanism on cardiac fibrosis in vivo and in vitro.