Dihydrotanshinone I preconditions myocardium against ischemic injury via PKM2 glutathionylation sensitive to ROS

Ischemic preconditioning (IPC) is a potential intervention known to protect the heart against ischemia/reperfusion injury, but its role in the no-reflow phenomenon that follows reperfusion is unclear. Dihydrotanshinone I (DT) is a natural compound and this study illustrates its role in cardiac ischemic injury from the aspect of IPC. Pretreatment with DT induced modest ROS production and protected cardiomyocytes against oxygen and glucose deprivation (OGD), but the protection was prevented by a ROS scavenger. In addition, DT administration protected the heart against isoprenaline challenge. Mechanistically, PKM2 reacted to transient ROS via oxidization at Cys423/Cys424, leading to glutathionylation and nuclear translocation in dimer form. In the nucleus, PKM2 served as a co-factor to promote HIF-1α-dependent gene induction, contributing to adaptive responses. In mice subjected to permanent coronary ligation, cardiac-specific knockdown of Pkm2 blocked DT-mediated preconditioning protection, which was rescued by overexpression of wild-type Pkm2, rather than Cys423/424-mutated Pkm2. In conclusion, PKM2 is sensitive to oxidation, and subsequent glutathionylation promotes its nuclear translocation. Although IPC has been viewed as a protective means against reperfusion injury, our study reveals its potential role in protection of the heart from no-reflow ischemia.

Drug target discovery by magnetic nanoparticles coupled mass spectrometry / 药物分析学报

Drug target discovery is the basis of drug screening.It elucidates the cause of disease and the mechanism of drug action,which is the essential of drug innovation.Target discovery performed in biological sys-tems is complicated as proteins are in low abundance and endogenous compounds may interfere with drug binding.Therefore,methods to track drug-target interactions in biological matrices are urgently required.In this work,a Fe3O4 nanoparticle-based approach was developed for drug-target screening in biofluids.A known ligand-protein complex was selected as a principle-to-proof example to validate the feasibility.After incubation in cell lysates,ligand-modified Fe3O4 nanoparticles bound to the target protein and formed complexes that were separated from the lysates by a magnet for further analysis.The large surface-to-volume ratio of the nanoparticles provides more active sites for the modification of chemical drugs.It enhances the opportunity for ligand-protein interactions,which is beneficial for capturing target proteins,especially for those with low abundance.Additionally,a one-step magnetic separation simplifies the pre-processing of ligand-protein complexes,so it effectively reduces the endogenous interference.Therefore,the present nanoparticle-based approach has the potential to be used for drug target screening in biological systems.

Protocatechuic aldehyde protects cardiomycoytes against ischemic injury

Rescuing cells from stress damage emerges a potential therapeutic strategy to combat myocardial infarction. Protocatechuic aldehyde (PCA) is a major phenolic acid in Chinese herb Danshen (

Prediction of fibril formation by early-stage amyloid peptide aggregation / 药物分析学报

Amyloid fibrils are found in systemic amyloidosis diseases such as Alzheimer's disease, Parkinson's disease, and type II diabetes. Currently, these diseases are diagnosed by observation of fibrils or plaques, which is an ineffective method for early diagnosis and treatment of disease. The goal of this study was to develop a simple and quick method to predict the possibility and speed of fibril formation before its occurrence. Oligomers generated from seven representative peptide segments were first isolated and detected by ion-mobility mass spectrometry (IM-MS). Then, their assemblies were disrupted using formic acid (FA). Interestingly, oligomers that showed small ion intensity changes upon FA addition had rapid fibril formation. By contrast, oligomers that had large ion intensity changes generated fibrils slowly. Two control peptides (aggregation/no fibrils and no aggregation/no fibrils) did not show changes in their ion intensities, which confirmed the ability of this method to predict amyloid formation. In summary, the developed method correlated MS intensity ratio changes of peptide oligomers on FA addition with their amyloid propensities. This method will be useful for monitoring peptide/protein aggregation behavior and essential for their mechanism studies.