Discovery of cinnamamide-barbiturate hybrids as a novel class of Nrf2 activator against myocardial ischemia/reperfusion injury

A novel anti-inflammatory strategy for myocardial ischemia-reperfusion in rats with cinnamamide derivative compound 7

Reperfusion after myocardial ischemia would aggravate myocardial structural and functional damage, known as myocardial ischemia-reperfusion (MI/R) injury. Cinnamamide derivatives have been reported to exert cardioprotective effects, and we have previously reported that compound 7 played a role in cardioprotection against MI/R via anti-inflammatory effect. However, exact mechanism underlying such beneficial action of compound 7 is still unclear. The protective effect of compound 7 was determined in H9c2 cells under H2O2 stimulation with or without nigerin (NLRP3 activator). Electrocardiogram, echocardiography, myocardial infarction size, histopathology and serum biochemical assay were performed in MI/R rats. Metabolomics in vivo and mRNA or protein levels of NLRP3, ASC, cleaved caspase-1 and its downstream IL-18 and IL-1β were detected both in vitro and in vivo. Compound 7 significantly ameliorate H2O2-induced cardiomyocyte damage, which was supported by in vivo data determined by improved left ventricular systolic function and histopathological changes, reduced myocardial infarction area and cellular apoptosis in heart tissue. Cardiac differential metabolites demonstrated that compound 7 indeed altered the cardiac reprogramming of inflammation-related metabolites, which was evidenced by down-regulated cardiac inflammation by compound 7. Additionally, compound 7 alleviated myocardial injury by inhibiting the NLRP3 pathway rather than other members of the inflammasome both in vitro and in vivo, which was further evidenced by CETSA assay. Whereas, nigerin blocked the inhibitory activity of compound 7 against NLRP3. Cinnamamide derivative compound 7 ameliorated MI/R injury by inhibiting inflammation via NLRP3.

Cardioprotective effect of Cinnamamide derivative compound 10 against myocardial ischemia-reperfusion through regulating cardiac autophagy via Sirt1

BACKGROUND AND PURPOSE

Our previous research discovered that cinnamamide derivatives are a new type of potential cardioprotective agents myocardial ischemia-reperfusion (MIR) injury, among which Compound 10 exhibits wonderful beneficial action in vitro. However, the exact mechanism of Compound 10 still needs to be elucidated.

EXPERIMENTAL APPROACH

The protective effect of Compound 10 was determined by detecting the cell viability and LDH leakage rate in H9c2 cells subjected to H2O2. Alterations of electrocardiogram, echocardiography, cardiac infarct area, histopathology and serum myocardial zymogram were tested in MIR rats. Additionally, the potential mechanism of Compound 10 was explored through PCR. Network pharmacology and Western blotting was conducted to monitor levels of proteins related to autophagic flux and mTOR, autophagy regulatory substrate, induced by Compound 10 both in vitro and in vivo, as well as expressions of Sirtuins family members.

KEY RESULTS

Compound 10 significantly ameliorated myocardial injury, as demonstrated by increased cell viability, decreased LDH leakage in vitro, and declined serum myocardial zymogram, ST elevation, cardiac infarct area and improved cardiac function and microstructure of heart tissue in vivo. Importantly, Compound 10 markedly enhanced the obstruction of autophagic flux and inhibited excessive autophagy initiation against MIR by decreased ATG5, Rab7 and increased P-mTOR and LAMP2. Furthermore, Sirt1 knockdown hindered Compound 10's regulation on mTOR, leading to interrupted cardiac autophagic flux.

CONCLUSIONS AND IMPLICATIONS

Compound 10 exerted cardioprotective effects on MIR by reducing excessive autophagy and improving autophgic flux blockage. Our work would take a novel insight in seeking effective prevention and treatment strategies against MIR injury.

Design and synthesis of matrine derivatives for anti myocardial ischemia-reperfusion injury by promoting angiogenesis

Myocardial ischemia/reperfusion (MI/R) is a common cardiovascular disease that seriously affects the quality of life and prognosis of patients. In recent years, matrine has attracted widespread attention in the treatment of cardiovascular diseases. This study designed, synthesized, and characterized 20 new matrine derivatives and studied their protective effects on ischemia-reperfusion injury through in vivo and in vitro experiments. Based on cellular assays, most newly synthesized derivatives have a certain protective effect on Hypoxia/Reoxygenation (H/R) induced H9C2 cell damage, with compound 22 having the best activity and effectively reducing cell apoptosis and necrosis. In vitro experimental data shows that compound 22 can significantly reduce the infarct size of rat myocardium and improve cardiac function after MI/R injury. In summary, compound 22 is a new potential cardioprotective agent that can promote angiogenesis and enhance antioxidant activity by activating ADCY5, CREB3l4, and VEGFA, thereby protecting myocardial cell apoptosis and necrosis induced by MI/R.

Structure-oriented engineering of nitrile hydratase: Reshaping of substrate access tunnel and binding pocket for efficient synthesis of cinnamamide

Cinnamamide and its derivatives are the most common and important building blocks widely present in natural products. Currently, nitrile hydratase (NHase, EC 4.2.1.84) has been widely used in large-scale industrial production of nicotinamide and acrylamide, while its catalytic activity is extremely low or inactive for bulky nitrile substrates such as cinnamonitrile. Therefore, beneficial variant βF37P/L48P/F51N were obtained from PtNHase of Pseudonocardia thermophila JCM3095 by reshaping of substrate access tunnel and binding pocket, which exhibited 14.88-fold improved catalytic efficiency compared to the wild-type PtNHase. Structure analysis, molecular dynamics simulations and dynamical cross-correlation matrix (DCCM) analysis revealed that the introduced mutations enlarged the substrate access tunnel and binding pocket, enhanced overall anti-correlated movements of enzymes, which would promote product release during the dynamic process of catalysis. In a hydration process, the complete conversion of 5 mM cinnamonitrile was achieved by βF37P/L48P/F51N in a 50 mL reaction, with cinnamamide yield of almost 100 % and productivity of 0.736 g L-1 h-1. The study demonstrates the co-evolution of substrate access tunnel and binding pocket is an effective strategy, and provides a valuable reference for future research. Furthermore, NHases have huge potential for catalyzing bulky nitriles to form corresponding amides in large-scale industrial production.