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

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.