Notch3 Ameliorates Cardiac Fibrosis After Myocardial Infarction by Inhibiting the TGF-β1/Smad3 Pathway

Abstract

Notch3 and TGF-β1 signaling play a key role in the pathogenesis and progression of chronic cardiovascular disease. However, whether Notch3 protects against myocardial infarction (MI) and the underlying mechanisms remains unknown. C57BL/6 mice were randomized to be treated with Notch3 siRNA (siNotch3) or lentivirus carrying Notch3 cDNA (Notch3) before coronary artery ligation. Four weeks after constructing MI model, cardiac function and fibrosis were compared between groups. The cardiac fibroblast cells (CFs) were isolated from newborn C57BL/6 mice (1-3 days old) and transfected with lentivirus carrying Notch3 cDNA. TGF-β1 (5 ng/ml), a well-known pro-fibrotic factor, was administered 72 h after Notch3 cDNA administration in CFs. The related proteins of fibrosis such as a-smooth muscle actin (a-SMA), Type I collagen, metalloprotease (MMP)-9 and the tissue inhibitor of metalloproteinases (TIMP)-2 were examined by western blot analysis. Notch3 cDNA treatment attenuated cardiac damage and inhibited fibrosis in mice with MI. Meanwhile, Notch3 siRNA administration aggravated cardiac function damage and markedly enhanced cardiac fibrosis in mice with MI. Overexpression of Notch3 inhibited TGF-β1-induced fibroblast-myofibroblast transition of mouse cardiac fibroblast cells, as evidenced by down-regulating a-SMA and Type I collagen expression. Notch3 cDNA treatment also increased MMP-9 expression and decreased TIMP-2 expression in the TGF-β1-stimulated cells. This study indicates that Notch3 is an important protective factor for cardiac fibrosis in a MI model, and the protective effect of Notch3 is attributable to its action on TGF-β1/Smad3 signaling.

Notch signaling inhibits cardiac fibroblast to myofibroblast transformation by antagonizing TGF‐β1/Smad3 signaling

“…Furthermore, Nemir et al showed that Notch activation in the stressed heart of adult mice inhibited TGF‐β1 induced CMT and cardiac fibrosis (Nemir et al, ). In addition, lentivirus‐mediated Notch3 overexpression inhibited CMT of TGF‐β1‐treated cardiac fibroblasts and ameliorated cardiac fibrosis in MI mice (Zhang et al, ). Consistent with recent studies, our results demonstrated that activated Notch signaling could inhibit TGF‐β1/Smad3 signaling mediated CMT in CFs and reduce myocardial fibrosis in MI rat model.…”

miR‐21 promotes cardiac fibroblast‐to‐myofibroblast transformation and myocardial fibrosis by targeting Jagged1

“…Myocardial infarction model was established in male Sprague‐Dawley (SD) rats using left anterior descending coronary artery (LAD) ligation method as described previously . The rats were anesthetized with sodium pentobarbital (60 mg/kg, ip) and a thoracotomy was performed.…”

Notch Signaling in Ischemic Damage and Fibrosis: Evidence and Clues from the Heart

“…Recently, in vivo intramyocardial delivery of hydrogels containing the Notch1 ligand Jagged-1 in rats with MI reduced cardiac fibrosis (Boopathy et al, 2015). Moreover, augmentation of Notch3 expression by lentiviral transfection inhibited fibroblast–myofibroblast transition both in TGF-β1-treated cardiac fibroblasts in vitro and in mice with MI, minimizing cardiac fibrosis (Zhang et al, 2016). As previously mentioned, Notch signaling can inhibit EMT (Zhou et al, 2015; Hu and Phan, 2016), which also contributes to cardiac fibrosis (von Gise and Pu, 2012).…”

“…The main identified mechanism by which Notch signaling interferes with myofibroblast differentiation consists in its ability to antagonize TGF-β/Smad3 signaling, the key intracellular pathway promoting cell activation and fibrogenesis (Zhang et al, 2016; Travers et al, 2016) ( Figure 2 ).…”