Extracts from Artemisia annua Alleviates Myocardial Remodeling through TGF-β1/Smad2/3 Pathway and NLRP3 Inflammasome

Background and objectives: Artemisinin and its derivatives, the well-known anti-malarial drugs extracted from traditional Chinese medicine, Artemisia annua, have been implicated in treating fibrotic diseases. However, whether artemisinin affects cardiac fibrosis in the pathogenesis of heart failure is still unknown. This study aimed to evaluate the possible effects of artemisinin on cardiac function and myocardial fibrosis in the heart failure model and to explore the underlying mechanisms.

Methods: Isoproterenol was injected subcutaneously for induction of the cardiac fibrosis model. Proteomic analysis was performed after 4 four weeks of artemisinin treatment. Echocardiography was used to evaluate cardiac function and structure. Hematoxylin and eosin (H&E) staining, as well as Masson trichrome staining, were performed for histopathology. The α-SMA, collagen I, and III expression in the myocardium was detected by immunohistochemical staining. The ratio of heart weight to body weight (HW/BW, mg/kg) and the ratio of heart weight to tibia length (HW/TL, mg/mm) were calculated as indicators for cardiac remodeling. Brain natriuretic peptide (BNP) levels were quantified in rat plasma using enzymelinked immunosorbent assay (ELISA). In contrast, the protein levels of TGF-β1, p-Smad2/3, and Smad2/3 were assessed in the myocardium and fibroblasts via western blot analysis. RT-qPCR was performed to analysis the expression of Col-I, Col-III, α-SMA, NLRP3, Caspase-1, IL-1β, and IL-18.

Results: Proteomic analysis identified 227 differentially expressed proteins (DEPs), including 119 upregulated and 108 downregulated proteins. These proteins were identified as the core proteins targeted by artemisinin for improving myocardial remodeling. GO annotation of the DEPs indicated that the DEPs were mainly associated with biological processes such as inflammation regulation. In the in vivo study of an isoproterenol-induced rat cardiac remodeling model, we found that artemisinin administration significantly ameliorated cardiac dysfunction and reduced collagen production by suppressing TGFβ-1/Smads signaling and inhibiting NLRP3 inflammasome activation. As manifested by downregulating the expression of α-SMA, Col-I, and Col-III, NLRP3, IL-1β, IL-18, Caspase-1 mRNA, and TGF-β1, p-SMAD 2/3 protein in the myocardium. Similar beneficial effects of artemisinin were consistently observed in TGF-β1 treated primary cardiac fibroblasts.

Conclusions: Extracts from Artemisia annua relieves myocardial remodeling through TGF-β1/Smad2/3 pathway and NLRP3 inflammasome