Objective To explore the mechanism of gallic acid targeting β-arrestin2 to inhibit astrocyte inflammation.

Methods Potential targets of gallic acid were found by PharmMapper and verified by thermal shift and molecular docking experiments. Western blot was used to detect the expression of β-arrestin2, NF-κB signaling pathway and NLRP3 inflammasome-related proteins; qPCR was used to detect the mRNA levels of proinflammatory cytokines such as IL-1β, IL-6 and TNF-α. A subacute PD mouse model induced by MPTP was established, and the behavioral ability of mice was evaluated by open field test, rotating rod test and climbing pole test; the number of TH+ and GFAP+ cells in the SNc area of mice was detected by immunohistochemistry; Western blot was used to detect the expression of NF-κB signaling pathway and NLRP3 inflammasome-related proteins in the homogenate protein of mouse midbrain tissue.

RESULTS Molecular docking experiments and thermal shift experiments showed that gallic acid could directly bind to β-arrestin2. Gallic acid could reduce the expression of p-IKK and p-P65 proteins in astrocytes (P < 0.001, P < 0.000 1), reduce the mRNA levels of IL-1β, IL-6 and TNF-α (P < 0.05, P < 0.01), and reduce the expression of caspase-1 and IL-1β proteins (P < 0.000 1), but had no effect on the expression of β-arrestin2 protein (P>0.05). Gallic acid could improve the behavioral ability of PD model mice, increase the number of TH+ neurons and GFAP+ cells in PD model mice (P < 0.05, P < 0.001), and reduce the expression of caspase-1, IL-1β, NLRP3 and p-IKK proteins in the brain of PD model mice (P < 0.05).

CONCLUSION Gallic acid inhibits the activation of NF-κB signaling pathway and NLRP3 inflammasome by binding to β-arrestin2 to reduce astrocyte inflammation, and has a neuroprotective effect on MPTP-induced PD model mice.