Shenmai Injection Alleviates Myocardial Ferroptosis via Activating the AKT1/mTOR Pathway in Rats with Acute Myocardial Infarction.

OBJECTIVE: Acute myocardial infarction (AMI) poses a serious burden on public health. Shenmai Injection (SMI) has been reported to have a cardioprotective effect and is used clinically attributed to its targeting of ferroptosis. This study aims to explore the underlying mechanisms of SMI in treating AMI through the application of network pharmacology analysis. METHODS: This study utilized network pharmacology to identify the bioactive ingredients and potential targets of SMI in treating AMI. A rat model of AMI was created by ligating the coronary arteries of rats, and a cell model was established by subjecting H9c2 cells to oxygen-glucose deprivation (OGD) to reveal the cardioprotective effects of SMI. Western blotting was employed to measure protein expressions, while hematoxylin-eosin staining was used to observe relevant pathological changes. Enzyme linked immunosorbent assay was conducted to measure the levels of biomarkers associated with cardiac injury and oxidative stress. RESULTS: A comprehensive analysis revealed a total of 225 putative targets of SMI in the context of AMI which exerted regulatory effects on numerous pathways and targeted multiple biological processes. AKT1 was identified as a core target mediating the effects of SMI on AMI by topological analysis. In vivo experiments revealed that SMI attenuated myocardial injury, oxidative stress, and ferroptosis in rats with AMI. Furthermore, SMI was found to enhance the expression levels of p-AKT1 and p-mTOR proteins in the myocardial tissues of rats afflicted with AMI. Similar findings were also observed in H9c2 cells subjected to OGD. Of particular interest, the suppression of OGD-induced iron accumulation, oxidative stress, and ferroptosis-associated proteins by SMI in H9c2 cells was reversed upon inhibition of the AKT1/mTOR pathway via MK2206. CONCLUSION: This study revealed that SMI exerts a protective effect against myocardial injury and ferroptosis caused by AMI via the activation of the AKT1/mTOR pathway.

TIEG1 deficiency confers enhanced myocardial protection in the infarcted heart by mediating the Pten/Akt signalling pathway.

The transforming growth factor (TGF)-ß-inducible early gene-1 (TIEG1) plays a crucial role in modulating cell apoptosis and proliferation in a number of diseases, including pancreatic cancer, leukaemia and osteoporosis. However, the functional role of TIEG1 in the heart has not been fully defined. In this study, we first investigated the role of TIEG1 in ischaemic heart disease. For in vitro experiments, cardiomyocytes were isolated from both TIEG1 knockout (KO) and wile-type (WT) mice, and the apoptotic ratios were evaluated after a 48­h ischaemic insult. A cell proliferation assay was performed after 7 days of incubation under normoxic conditions. In addition, the angiogenic capacity of endothelial cells was determined by tube formation assay. For in vivo experiments, a model of myocardial infarction (MI) was established using both TIEG1 KO and WT mice. Echocardiography was performed at 3 and 28 days post-MI, whereas the haemodynamics test was performed 28 days post-MI. Histological analyses of apoptosis, proliferation, angiogenesis and infarct zone assessments were performed using terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) staining, BrdU immunostaining, α-smooth muscle actin (α-SMA)/CD31 immunostaining and Masson's trichrome staining, respectively. Changes in the expression of related proteins caused by TIEG1 deficiency were confirmed using both reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Our results demonstrated that the absence of TIEG1 prevented cardiomyocytes from undergoing apoptosis and promoted higher proliferation; it stimulated the proliferation of endothelial cells in vitro and in vivo. Improved cardiac function and less scar formation were observed in TIEG1 KO mice, and we also observed the altered expression of phosphatase and tensin homolog (Pten), Akt and Bcl-2/Bax, as well as vascular endothelial growth factor (VEGF). On the whole, our findings indicate that the absence of TIEG1 plays a cardioprotective role in ischaemic heart disease by promoting changes in Pten/Akt signalling.