myricetin and Inflammation

Accumulation of tau protein aggregation plays a crucial role in neurodegenerative diseases, such as Alzheimer's disease (AD). Uncontrollable neuroinflammation and tau pathology form a vicious circle that further aggravates AD progression. Herein, we reported the synthesis of usnic acid derivatives and evaluation of their inhibitory activities against tau-aggregation and neuroinflammation. The inhibitory activity of the derivatives against the self-fibrillation of the hexapeptide AcPHF6 was initially screened by ThT fluorescence assay. Using circular dichroism and transmission electron microscopy, compound 30 showed the most potent inhibitory activity against AcPHF6 self-fibrillation. Compound 30 was further confirmed to inhibit the aggregation of full-length 2N4R tau protein by a heparin-induced mechanism. In addition, we investigated the anti-inflammatory activity of compound 30, and showed that compared with sodium usnate, it reduced NO release in LPS-stimulated mouse microglia BV2 cells. More importantly, 30 showed significant protective effects against okadaic acid-induced memory impairment in rats. Thus, 30 was a novel tau-aggregation and neuroinflammation inhibitor that represented a potential therapeutic candidate for AD.

Topics: Alzheimer Disease; Animals; Benzofurans; Cell Line, Tumor; Disease Models, Animal; Dose-Response Relationship, Drug; Humans; Inflammation; Lipopolysaccharides; Male; Maze Learning; Mice; Models, Molecular; Molecular Structure; Nitric Oxide; Protein Aggregates; Rats; Rats, Sprague-Dawley; Structure-Activity Relationship; tau Proteins

This protocol describes microsphere-based protease assays for use in flow cytometry and high-throughput screening. This platform measures a loss of fluorescence from the surface of a microsphere due to the cleavage of an attached fluorescent protease substrate by a suitable protease enzyme. The assay format can be adapted to any site or protein-specific protease of interest and results can be measured in both real time and as endpoint fluorescence assays on a flow cytometer. Endpoint assays are easily adapted to microplate format for flow cytometry high-throughput analysis and inhibitor screening.

Topics: Animals; Biotinylation; Flow Cytometry; Fluorescence Resonance Energy Transfer; Green Fluorescent Proteins; High-Throughput Screening Assays; Humans; Inflammation; Kinetics; Microspheres; Peptide Hydrolases; Peptides; Reproducibility of Results; Temperature