Protein Tyrosine Phosphatase 1B Inhibitors of Pueraria lobata Based on the Spectrum-Effect Relationship by Q-Marker Selection.

Pueraria lobata (P. lobata), a traditional anti-diabetic medicine mainly composed of flavonoids and isoflavones, has a long history in diabetes treatment in China. However, the anti-diabetic active component is still unclear. Recently, protein tyrosine phosphatase 1B (PTP1B) has been a hot therapeutic target by negatively regulating insulin signaling pathways. In this study, the spectrum-effect relationship analysis method was first used to identify the active components of P. lobata that inhibit PTP1B. The fingerprints of 12 batches of samples were established using high-performance liquid chromatography (HPLC), and sixty common peaks were identified. Meanwhile, twelve components were identified by a comparison with the standards. The inhibition of PTP1B activity was studied in vitro by using the p-nitrophenol method, and the partial least squares discriminant analysis, grey relational analysis, bivariate correlation analysis, and cluster analysis were used to analyze the bioactive compounds in P. lobata. Peaks 6, 9 (glycitin), 11 (genistin), 12 (4'-methoxypuerarin), 25, 34, 35, 36, 53, and 59 were considered as potentially active substances that inhibit PTP1B. The in vitro PTP1B inhibitory activity was confirmed by glycitin, genistin, and 4'-methoxypuerarin. The IC50s of the three compounds were 10.56 ± 0.42 µg/mL, 16.46 ± 0.29 µg/mL, and 9.336 ± 0.56 µg/mL, respectively, indicating the obvious PTP1B inhibitory activity. In brief, we established an effective method to identify PTP1B enzyme inhibitors in P. lobata, which is helpful in clarifying the material basis of P. lobata on diabetes. Additionally, it is evident that the spectrum-effect relationship method serves as an efficient approach for identifying active compounds, and this study can also serve as a reference for screening bioactive constituents in traditional Chinese medicine.

Protein corona between nanoparticles and bacterial proteins in activated sludge: Characterization and effect on nanoparticle aggregation.

In this work, the protein coronas of activated sludge proteins on TiO2 nanoparticles (TNPs) and ZnO nanoparticles (ZNPs) were characterized. The proteins with high affinity to TNPs and ZNPs were identified by shotgun proteomics, and their effects of on the distributions of TNPs and ZNPs in activated sludge were concluded. In addition, the effects of protein coronas on the aggregations of TNPs and ZNPs were evaluated. Thirty and nine proteins with high affinities to TNPs and ZNPs were identified, respectively. The proteomics and adsorption isotherms demonstrated that activated sludge had a higher affinity to TNPs than to ZNPs. The aggregation percentages of ZNPs at 35, 53, and 106 mg/L of proteins were 13%, 14%, and 18%, respectively, whereas those of TNPs were 21%, 30%, 41%, respectively. The proteins contributed to ZNPs aggregation by dissolved Zn ion-bridging, whereas the increasing protein concentrations enhanced the TNPs aggregation through macromolecule bridging flocculation.

Arrhythmogenic remodeling of ß2 versus ß1 adrenergic signaling in the human failing heart.

BACKGROUND: Arrhythmia is the major cause of death in patients with heart failure, for which ß-adrenergic receptor blockers are a mainstay therapy. But the role of ß-adrenergic signaling in electrophysiology and arrhythmias has never been studied in human ventricles. METHODS AND RESULTS: We used optical imaging of action potentials and [Ca(2+)]i transients to compare the ß1- and ß2-adrenergic responses in left ventricular wedge preparations of human donor and failing hearts. ß1-Stimulation significantly increased conduction velocity, shortened action potential duration, and [Ca(2+)]i transients duration (CaD) in donor but not in failing hearts, because of desensitization of ß1-adrenergic receptor in heart failure. In contrast, ß2-stimulation increased conduction velocity in both donor and failing hearts but shortened action potential duration only in failing hearts. ß2-Stimulation also affected transmural heterogeneity in action potential duration but not in [Ca(2+)]i transients duration. Both ß1- and ß2-stimulation augmented the vulnerability and frequency of ectopic activity and enhanced substrates for ventricular tachycardia in failing, but not in donor, hearts. Both ß1- and ß2-stimulation enhanced Purkinje fiber automaticity, whereas only ß2-stimulation promoted Ca-mediated premature ventricular contractions in heart failure. CONCLUSIONS: During end-stage heart failure, ß2-stimulation creates arrhythmogenic substrates via conduction velocity regulation and transmurally heterogeneous repolarization. ß2-Stimulation is, therefore, more arrhythmogenic than ß1-stimulation. In particular, ß2-stimulation increases the transmural difference between [Ca(2+)]i transients duration and action potential duration, which facilitates the formation of delayed afterdepolarizations.