Aesculin suppresses the NLRP3 inflammasome-mediated pyroptosis via the Akt/GSK3ß/NF-κB pathway to mitigate myocardial ischemia/reperfusion injury.

BACKGROUND: Aesculin (AES), an effective component of Cortex fraxini, is a hydroxycoumarin glucoside that has diverse biological properties. The nucleotide-binding domain leucine-rich repeat-containing receptor, pyrin domain-containing 3 (NLRP3) inflammasome has been heavily interwoven with the development of myocardial ischemia/reperfusion injury (MIRI). Nevertheless, it remains unclear whether AES makes a difference to the changes of the NLRP3 inflammasome in MIRI. PURPOSE: We used rats that were subjected to MIRI and neonatal rat cardiomyocytes (NRCMs) that underwent oxygen-glucose deprivation/restoration (OGD/R) process to investigate what impacts AES exerts on MIRI and the NLRP3 inflammasome activation. METHODS: The establishment of MIRI model in rats was conducted using the left anterior descending coronary artery ligation for 0.5 h ischemia and then untying the knot for 4 h of reperfusion. After reperfusion, AES were administered intraperitoneally using 10 and 30 mg/kg doses. We evaluated the development of reperfusion ventricular arrhythmias, hemodynamic changes, infarct size, and the biomarkers in myocardial injury. The inflammatory mediators and pyroptosis were also assessed. AES at the concentrations of 1, 3, and 10 µM were imposed on the NRCMs immediately before the restoration process. We also determined the cell viability and cell death in the NRCMs exposed to OGD/R insult. Furthermore, we also analyzed the levels of proteins that affect the NLRP3 inflammasome activation, pyroptosis, and the AKT serine/threonine kinase (Akt)/glycogen synthase kinase 3 beta (GSK3ß)/nuclear factor-kappa B (NF-κB) signaling pathway via western blotting. RESULTS: We found that AES notably attenuated reperfusion arrhythmias and myocardia damage, improved the hemodynamic function, and ameliorated the inflammatory response and pyroptosis of cardiomyocytes in rats and NRCMs. Additionally, AES reduced the NLRP3 inflammasome activation in rats and NRCMs. AES also enhanced the phosphorylation of Akt and GSK3ß, while suppressing the phosphorylation of NF-κB. Moreover, the allosteric Akt inhibitor, MK-2206, abolished the AES-mediated cardioprotection and the NLRP3 inflammasome suppression. CONCLUSIONS: These findings indicate that AES effectively protected cardiomyocytes against MIRI by suppressing the NLRP3 inflammasome-mediated pyroptosis, which may relate to the upregulated Akt activation and disruption of the GSK3ß/NF-κB pathway.

Formononetin ameliorates myocardial ischemia/reperfusion injury in rats by suppressing the ROS-TXNIP-NLRP3 pathway.

Formononetin (FN), a methoxy isoflavone abundant in many plants and herbs, has been evidently proven to possess multiple medicinal properties. Our study aimed to clarify the impact of FN on myocardial ischemia/reperfusion (I/R) injury (MIRI) and the involved mechanism. A rat model of MIRI was produced by ligation and loosening of the left anterior descending (LAD) branch of the coronary artery. Rats received 10 and 30 mg/kg of FN when the reperfusion started. At 24 h after surgery, cardiac function, infarct size, and sera levels of the cardiac markers and inflammatory mediators were measured. To mimic the inflammasome activation in cardiomyocytes, neonatal rat cardiomyocytes (NRCMs) were cultured and treated with lipopolysaccharide (LPS) plus nigericin. Cell death and reactive oxygen species (ROS) were determined. Myocardial expression and activation of the nucleotide-binding domain and leucine-rich repeat-containing protein 3 (NLRP3) inflammasome in rats were examined by western blotting. The level of thioredoxin interacting protein (TXNIP)-NLRP3 interaction was assessed. FN notably attenuated cardiac dysfunction, infarct size, release of cardiac markers, and elevation of TNF-α, IL-1ß, and IL-6. FN alleviated LPS plus nigericin-induced injury and ROS increase in NRCMs. Western blotting revealed that FN suppressed the activation of NLRP3 inflammasome and TXNIP-NLRP3 interaction in rats. These findings indicate that FN ameliorated MIRI in rats and inhibited the activation of the NLRP3 inflammasome, at least partially, attributable to suppression of the ROS-TXNIP-NLRP3 pathway.

Pharmacogenetics of SLCO1B1: haplotypes, htSNPs and hepatic expression in three distinct Asian populations.

OBJECTIVE: The aim of this study was to characterize the population frequency of SLCO1B1 polymorphic variants in three distinct healthy Asian populations, namely Chinese (n = 100), Malay (n = 100) and Indian (n = 100), and to explore the association between haplotype-tagged single nucleotide polymorphisms (htSNPs) on hepatic SLCO1B1 mRNA expression. METHODS: The distribution of polymorphic variants in the SLCO1B1 gene at eight loci that spanned approximately 48 kb was investigated in the three different Asian ethnic groups and in 32 non-cancerous liver tissues from Chinese patients. RESULTS: Of the 26 polymorphisms screened, we found eight polymorphic variants that differed in genotypic and allelic frequencies between the Chinese, Malay and Indian populations. Significant interethnic differences were observed in the genotype frequency distributions across the promoter SNP [g.-11187G>A (P = 0.030)] as well as three coding region SNPs [c.388G>A (P < 0.001); c.571T>C (P < 0.001); c.597C>T (P < 0.001)] in the healthy subjects. Haplotype analysis revealed 12 different haplotypes in both the Chinese and Malay populations and 18 haplotypes in the Indian population. In both the Malay and Indian populations, the htSNPs were c.388A>G, c.571T>C and c.597C>T, whereas in the Chinese population they were g.-11187G>A, c.388A>G and c.597C>T. The c.388A>G and c.597C>T htSNPs accounted for more than 70% of the variations between the three major haplotypes in each Asian ethnic group. In terms of the c.388A>G htSNPs, genotypic-phenotypic association analyses revealed that there was no effect on SLCO1B1 expression in hepatic tissues; in addition, no genotypic-phenotypic associations were evident with regards to the c.597C>T htSNP. CONCLUSION: Future studies should investigate the phenotypic effects of the c.388A>G htSNP on the disposition of OATP1B1 substrates in Asian populations.