Isoliquiritigenin alleviates myocardial ischemia-reperfusion injury by regulating the Nrf2/HO-1/SLC7a11/GPX4 axis in mice.

Ischemia-reperfusion (I/R) injury, a multifaceted pathological process, occurs when the prolongation of reperfusion duration triggers ferroptosis-mediated myocardial damage. Isoliquiritigenin (ISL), a single flavonoid from licorice, exhibits a wide range of pharmacological impacts, but its function in ferroptosis caused by myocardial I/R injury remains unclear. This study delved into the protective effect of ISL on myocardial I/R injury-induced ferroptosis and its mechanism. Neonatal mouse cardiomyocytes (NMCM) underwent hypoxia/reoxygenation (H/R) to simulate the pathological process of myocardial I/R. ISL significantly attenuated H/R-triggered production of reactive oxygen species in NMCM, reduced the expression of malondialdehyde and the activity of lactate dehydrogenase, enhanced superoxide dismutase and catalase activity, and increased the expression of nuclear factor E2-related factor 2 (Nrf2) and its downstream heme oxygenase 1 (HO-1), thereby mitigating oxidative stress damage. CCK8 experiment revealed that the ferroptosis inhibitor Ferrostatin-1 significantly improved myocardial cell viability after 24 h of reoxygenation, and ISL treatment showed a similar effect. ISL reduced intracellular free iron accumulation, up-regulated glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression, and inhibited lipid peroxidation accumulation, thereby alleviating ferroptosis. The Nrf2-specific inhibitor ML385 counteracted ISL's defensive role against H/R-triggered oxidative stress damage and ferroptosis. In vivo experiments further confirmed that by regulating the translocation of Nrf2 into the nucleus, ISL treatment increased the levels of HO-1, GPX4, and SLC7A11, inhibited the expression of ACSL4, Drp1 to exert the antioxidant role, alleviated mitochondrial damage, and ferroptosis, ultimately reducing myocardial infarction area and injury induced by I/R. ML385 nearly abolished ISL's protective impact on the I/R model by inhibiting Nrf2 function. In summary, ISL is capable of mitigating oxidative stress, mitochondrial damage, and cardiomyocyte ferroptosis caused by I/R, thereby reducing myocardial injury. A key mechanism includes triggering the Nrf2/HO-1/SLC7A11/GPX4 pathway to prevent oxidative stress damage and cardiomyocyte ferroptosis caused by I/R.

Ecliptasaponin A protects heart against acute ischemia-induced myocardial injury by inhibition of the HMGB1/TLR4/NF-κB pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Eclipta prostrata (Linn.) is a traditional medicinal Chinese herb that displays multiple biological activities, such as encompassing immunomodulatory, anti-inflammatory, anti-tumor, liver-protective, antioxidant, and lipid-lowering effects. Ecliptasaponin A (ESA), a pentacyclic triterpenoid saponin isolated from Eclipta prostrata (Linn.), has been demonstrated to exert superior anti-inflammatory activity against many inflammatory disorders. AIM OF THE STUDY: Inflammation plays a critical role in acute myocardial infarction (AMI). This study aims to explore the treatment effects of ESA in AMI, as well as the underlying mechanism. METHODS: An AMI mouse model was established in mice via left anterior descending coronary artery (LAD) ligation. After surgery, ESA was injected at doses of 0.5, 1.25, and 2.5 mg/kg, respectively. Myocardial infarction size, cardiomyocyte apoptosis and cardiac echocardiography were studied. The potential mechanism of action of ESA was investigated by RNA-seq, Western blot, surface plasmon resonance (SPR), molecular docking, and immunofluorescence staining. RESULTS: ESA treatment not only significantly reduced myocardial infarct size, decreased myocardial cell apoptosis, and inhibited inflammatory cell infiltration, but also facilitated to improve cardiac function. RNA-seq and Western blot analysis proved that ESA treatment-induced differential expression genes mainly enriched in HMGB1/TLR4/NF-κB pathway. Consistently, ESA treatment resulted into the down-regulation of IL-1ß, IL-6, and TNF-α levels after AMI. Furthermore, SPR and molecular docking results showed that ESA could bind directly to HMGB1, thereby impeding the activation of the downstream TLR4/NF-κB pathway. The immunofluorescence staining and Western blot results at the cellular level also demonstrated that ESA inhibited the activation of the HMGB1/TLR4/NF-κB pathway in H9C2 cells. CONCLUSION: Our study was the first to demonstrate a cardiac protective role of ESA in AMI. Mechanism study indicated that the treatment effects of ESA are mainly attributed to its anti-inflammatory activity that was mediated by the HMGB1/TLR4/NF-κB pathway.

Neutrophil membrane biomimetic delivery system (Ptdser-NM-Lipo/Fer-1) designed for targeting atherosclerosis therapy.

Atherosclerosis is a progressive inflammatory disease characterised by excessive lipid accumulation and inflammatory cell infiltration and is the basis of most cardiovascular diseases and peripheral arterial diseases. Therefore, an effectively targeted delivery system is urgently needed to deliver ferroptosis-specific inhibitors to the site of arterial plaque and the inflammatory microenvironment. Inspired by the fact that neutrophils can be recruited to arterial plaques under the action of adhesion molecules and chemokines, the authors developed a neutrophil membrane hybrid liposome nano-mimetic system (Ptdser-NM-Lipo/Fer-1) that delivers Ferrostatin-1 (Fer-1) to the atherosclerotic plaque effectively, which is composed of Fer-1-loaded Ptdser-modified liposomes core and neutrophils shell. Fer-1 was released at the AS plaque site to remove reactive oxygen species (ROS) and improve the inflammatory microenvironment. In vitro ROS clearance experiments have shown that 50 µmol/ml Fer-1 can significantly remove ROS produced by H2 O2 -induced MOVAS cells and Ptdser-NM-Lipo/Fer-1 revealed a 3-fold increase in the inhibition rate of ROS than free Fer-1 in induced-RAW264.7, demonstrating its superior ROS-cleaning effect. Based on the interaction of adhesion molecules, such as vascular cell adhesion molecule 1, ICAM-1, P-selectin, E-selectin, and chemokines released in the inflamed site, the aorta in NM-Lipo-treated mice displayed 1.3-fold greater radiant efficiency than platelet membrane-Lipo-treated mice. Meanwhile, due to the modification of the Ptdser, the aorta in Ptdser-NM-Lipo/Fer-1-treated mice exhibited the highest fluorescence intensity, demonstrating its excellent targeting ability for atherosclerosis. Therefore, we present a specific formulation for the treatment of atherosclerosis with the potential for novel therapeutic uses.

Identification of key differential genes in intimal hyperplasia induced by left carotid artery ligation.

Background: Intimal hyperplasia is a common pathological process of restenosis following angioplasty, atherosclerosis, pulmonary hypertension, vein graft stenosis, and other proliferative diseases. This study aims to screen for potential novel gene targets and mechanisms related to vascular intimal hyperplasia through an integrated microarray analysis of the Gene Expression Omnibus Database (GEO) database. Material and Methods: The gene expression profile of the GSE56143 dataset was downloaded from the Gene Expression Omnibus database. Functional enrichment analysis, protein-protein interaction (PPI) network analysis, and the transcription factor (TF)-target gene regulatory network were used to reveal the biological functions of differential genes (DEGs). Furthermore, the expression levels of the top 10 key DEGs were verified at the mRNA and protein level in the carotid artery 7 days after ligation. Results: A total of 373 DEGs (199 upregulated DEGs and 174 downregulated DEGs) were screened. These DEGs were significantly enriched in biological processes, including immune system process, cell adhesion, and several pathways, which were mainly associated with cell adhesion molecules and the regulation of the actin cytoskeleton. The top 10 key DEGs (Ptprc, Fn1, Tyrobp, Emr1, Itgb2, Itgax, CD44, Ctss, Ly86, and Aif1) acted as key genes in the PPI network. The verification of these key DEGs at the mRNA and protein levels was consistent with the results of the above-mentioned bioinformatics analysis. Conclusion: The present study identified key genes and pathways involved in intimal hyperplasia induced by carotid artery ligation. These results improved our understanding of the mechanisms underlying the development of intimal hyperplasia and provided candidate targets.

Isoliquiritigenin Ameliorates Ischemia-Induced Myocardial Injury via Modulating the Nrf2/HO-1 Pathway in Mice.

Background: Oxidative stress and inflammatory reaction play critical roles in acute myocardial infarction (AMI). Isoliquiritigenin (ISL), a flavonoid monomer extracted from licorice, has been found to have antioxidant and anti-inflammatory effects in cancer studies. Here, we tested the effect and underlying mechanisms of ISL on ischemia-induced myocardial injury in a mouse AMI model. Methods: Adult C57BL/6 mice were pre-treated by intraperitoneal injection of ISL and/or a specific nuclear factor E2-related factor 2 (Nrf2) inhibitor ML385 for 3 days, respectively. Then, the AMI model was established by ligating the anterior descending branch of the left coronary artery. Myocardial oxidative stress status, inflammatory response, cardiac function and infarction size were assessed after 7th day of surgery. Results: Compared with sham group, the reactive oxygen species (ROS) and malondialdehyde (MDA) level in AMI group were significantly increased. However, the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) level were dramatically decreased. ISL treatment significantly reduced the myocardial infarction area, improved cardiac function, inhibited the production of ROS and MDA and reduced the consumption of SOD and GSH-Px. Interestingly, ISL could significantly increase nuclear Nrf2 and cytosolic heme oxygenase 1 (HO-1) level in the infarcted myocardium and reduce the oxidative stress after AMI. Also, ISL treatment dramatically inhibited the activation of myocardial NF-κB pathway and reduced the expression of pro-inflammatory factors in the AMI group. However, the administration of ML385 not only suppressed the Nrf2/HO-1 activation, the anti-oxidant and anti-inflammatory effects induced by ISL, but also attenuated the beneficial role of ISL on reducing infarct size and improving cardiac function in the mouse with AMI. Conclusion: The results suggested that activation of Nrf2/HO-1 pathway has an essential role in ISL-induced cardiac protection by alleviating myocardial oxidative stress and inflammation response in mice with AMI.