Extracts from Artemisia annua Alleviates Myocardial Remodeling through TGF-ß1/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-ß1, 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-1ß, 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 TGFß-1/Smads signaling and inhibiting NLRP3 inflammasome activation. As manifested by downregulating the expression of α-SMA, Col-I, and Col-III, NLRP3, IL-1ß, IL-18, Caspase-1 mRNA, and TGF-ß1, p-SMAD 2/3 protein in the myocardium. Similar beneficial effects of artemisinin were consistently observed in TGF-ß1 treated primary cardiac fibroblasts. CONCLUSIONS: Extracts from Artemisia annua relieves myocardial remodeling through TGF-ß1/Smad2/3 pathway and NLRP3 inflammasome

IFITM3 mediates inflammation induced myocardial injury through JAK2/STAT3 signaling pathway.

Myocarditis is an inflammation of the heart muscle often associated with viral infections and can lead to dilated cardiomyopathy. Interferon-induced transmembrane protein 3 (IFITM3) is a small endosomal membrane protein with anti-viral activity against multiple viruses and is also implicated in non-infectious diseases such as cancer and Alzheimer's Disease. Since the IFITM3 proteins are expressed both in T cells and in cardiomyocytes, it is reasonable to hypothesize that these molecules could affect myocarditis either through their effect on the autoimmune response or through direct modulation of cardiomyocyte damage. The aim of this study was to investigate the role of IFITM3 in experimental autoimmune myocarditis (EAM)-mediated myocardial injury. Immunization of rats with cardiac myosin results in substantial cardiac inflammation and is associated with increased expression of IFITM3 after 21 days. In vivo IFITM3 shRNA knockdown using the lentivirus transfection method reduced cardiac injury while restoring IFITM3 expression reversed the protective effect of IFITM3 RNA interference. To determine the direct impact of IFITM3, the rat ventricular cell line, H9c2, was treated with palmitic acid which causes apoptosis in these cells. Suppressing IFITM3 expression protects H9c2 cells while overexpressing IFITM3 enhances cell injury. JAK inhibitors reduced IFITM3-mediated myocardial cell injury. In conclusion, IFITM3 may mediate myocardial injury in EAM rats and palmitic acid-induced damage to H9c2 cells through the JAK2/STAT3 pathway.

Inhibition of Mogroside IIIE on isoproterenol-induced myocardial fibrosis through the TLR4/MyD88/NF-κB signaling pathway.

Objectives: To investigate the effect of mogroside IIIE (MGIIIE) on isoproterenol (ISO)-induced myocardial fibrosis and explore its possible mechanisms. Materials and Methods: Forty C57BL/6 male mice (6-8 weeks) were randomly divided into a control group (n=10), model group (n=10), low MGIIIE dose group (n=10), and high MGIIIE dose group (n=10). Myocardial fibrosis was established by subcutaneous ISO injection. After 2 weeks of continuous gastric administration of MGIIIE, the cardiac structure was evaluated by echocardiography. Myocardial inflammation and fibrosis were evaluated by histology examination. Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), p-IκBα, p-NF-κB, transforming growth factor ß1 (TGF-ß1), and α-smooth muscle actin (α-SMA) expression were detected by western blot. Inflammatory cytokines (IL-1ß, IL-6, and TNF-α) in the serum were examined by ELISA. In the in vitro study, Ang II (1 µmol/l) was used to stimulate the fibroblasts, then inflammation and fibrosis index were detected. Results: MGIIIE inhibited inflammation and fibrosis and down-regulated TLR4, MyD88, TGF-ß1, and α-SMA expression in the myocardium. In the in vitro study, MGIIIE ameliorates the deposition of Col Ш and Col I and decreases the release of inflammatory cytokines. MGIIIE increased p-IκBα and reduced p-NF-κB expression both in vivo and in vitro. Conclusion: MGIIIE plays a role in anti-myocardial fibrosis, by inhibiting TLR4/MyD88/NF-κB signaling expression, and decreasing inflammatory cytokine release. MGIIIE may represent a novel therapeutic strategy for treating cardiac fibrosis.