Elucidation of the binding mechanism of astragaloside IV derivative with human serum albumin and its cardiotoxicity in zebrafish embryos.

LS-102 is a new derivative of astragaloside IV (AGS IV) that has been shown to possess potentially significant cardioprotective effects. However, there are no reports concerning its interaction with human serum albumin (HSA) and toxicology in vertebrates. The present investigation was undertaken to characterize the interaction of AGS IV and LS-102 with HSA using equilibrium dialysis and UHPLC-MS/MS methods, along with computational methods. Notably, the effects of AGS IV and LS-102 were studied in vivo using the zebrafish embryo model. Markers related to embryonic cardiotoxicity and thrombosis were evaluated. We showed that the plasma protein binding rate of AGS IV (94.04%-97.42%) was significantly higher than that of LS-102 (66.90%-69.35%). Through site marker competitive experiments and molecular docking, we found that AGS IV and LS-102 were located at the interface of subdomains IIA and IIIA, but the site I might be the primary binding site. Molecular dynamics revealed that AGS IV showed a higher binding free energy mainly due to the stronger hydrophobic and hydrogen bonding interactions. Moreover, the secondary structure implied no obvious effect on the protein structure and conformation during the binding of LS-102. LS-102 significantly ameliorated the astramizole-induced heart rate slowing, increased SV-BA spacing, and prevented arachidonic acid-induced thrombosis in zebrafish. To our knowledge, we are the first to reveal that LS-102 binds to HSA with reversible and moderate affinity, indicating its easy diffusion from the circulatory system to the target tissue, thereby providing significant insights into its pharmacokinetic and pharmacodynamic properties when spread in the human body. Our results also provide a reference for the rational clinical application of LS-102 in the cardiovascular field.

Application of serum exosomal hypoxia-inducible factor-1 alpha (HIF-1α) as potential circulating biomarker for bacterial peritonitis.

Bacterial peritonitis is a severe disease that diagnosis remains challenging for clinicians. Measuring biomarkers might be a rapid diagnostic method. The objective of this study was to analyze and evaluate the dynamic changes in HIF-1α concentration in serum exosomes during bacterial peritonitis. The pre-clinical application value of serum exosomal HIF-1α was evaluated via imipenem and cilastatin sodium (ICS) intervention in the bacterial peritonitis model. The new colorimetric method to quantitate dynamic expression changes of HIF-1α in serum exosomes during bacterial peritonitis was established by our team via using the gold seed-coated with aptamer-functionalized Au @ Au core-shell peroxidase mimic. The typical inflammatory cytokines of bacterial peritonitis were also measured. Following intramuscular administration with ICS, In-Vivo Xtreme imaging system was used to visualize abdominal infection extent. Meanwhile, HIF-1α concentration in rat serum exosomes and pro-inflammatory factors levels in serum were detected. The serum typical inflammatory cytokines levels were elevated in GFP-labeled E.coli induced bacterial peritonitis. The serum exosomal HIF-1α levels clearly increased at 12 h, reached the peak during 24-48 h, and then gradually decreased at 72 h. Following intramuscular administration with ICS, the abdominal infection extent, HIF-1α concentration in serum exosomes, and the serum pro-inflammatory factors levels were reduced at 24 h in GFP-labeled E. coli induced bacterial peritonitis model. The serum exosomal HIF-1α can be used as a biomarker in the early stage of bacterial peritonitis, which might provide the basic research in the pre-clinical for further predicting and monitoring the pathological process of bacterial peritonitis.

Identification of Active Compounds From Yi Nationality Herbal Formula Wosi Influencing COX-2 and VCAM-1 Signaling.

The Yi nationality herbal formula Wosi is used in China as a folk medicine to treat arthritis and related diseases. Despite its widespread use, the active ingredients, and pharmacological mechanisms are not performed. This is the first time to identify the active compounds from Wosi with the aim at providing the potential effect of Wosi and exploring its underlying anti-inflammatory mechanism in monosodium urate crystals (MSU)-induced arthritis rats. In this study, anti-hyperuricemia effect was assessed by reducing the serum uric acid levels and increasing uric acid excretion in the urine for the hyperuricemia rat model. Wosi significantly suppressed the degree of joint swelling and improved the symptoms of inflammation induced by MSU crystals. The inhibition of IL-2, IL-1ß, IFN-γ, and IL-6 secretion and IL-10 increase in the serum were also observed. This study also focuses on the screening of the main compounds from Wosi against cyclooxygenase for anti-inflammatory properties using molecular docking. The result showed 3-O-[α-L-pyran rhamnose(1-3)-ß-D-pyran glucuronic acid]- oleanolic acid, 3-O-(ß-D-pyran glucuronic acid)-oleanolic acid-28-O-ß-D-pyran glucoside, and 3-O-[α-L-pyran rhamnose(1-3)-ß-D-pyran glucuronic acid]-oleanolic acid-28-O-ß-D-pyran glucoside with a higher binding affinity for COX-2 than COX-1 which indicated relatively higher interaction than COX-1. The preferential selectivity toward inhibiting COX-2 enzyme over COX-1 of three compounds from Wosi were evaluated using in-vitro cyclooxygenases 1 and 2 (COX-1/2) inhibition assays. Meanwhile, the down-regulated protein expression of COX-2 and VCAM-1 in synovial tissue sections from ankle joints of experiments rats were confirmed by immunohistochemistry analysis after the Wosi treatment. In conclusion, three oleanolic acid glycosides were implied as mainly efficient compounds in Yi nationality herbal formula Wosi for arthritis therapy via selectively influencing COX-2 and VCAM-1 signaling.