USP7 - A novel target for controlling periodontal inflammation through modulation of macrophage polarization

Disruption of local microbial irritation and host immune response can result in inflammation and tissue destruction in periodontitis. Studies on the modulation of macrophage polarization could help attenuate immune responses in periodontal tissues. To investigate the effect of ubiquitin-specific protease-7 (USP7) and its inhibitor P5091 on the polarization of macrophages in periodontitis, gene expression in periodontitis tissues and normal control were analyzed via single-cell RNA sequencing data and mice model experimental periodontitis. RAW264.7 cells were induced to M1 polarization with LPS + IFN-γ and M2 polarization with IL-4. USP7 was knocked down using lentivirus, and the effect of USP7 inhibitor P5091 on macrophage polarization was comparatively analyzed. The expression of Usp7 and polarization markers were detected by qRT-PCR. Western blot was used to examine the polarization markers and pathway-associated proteins. Results indicated that USP7 expression was elevated in tissues affected by periodontitis. Periodontitis macrophages and M1 polarized macrophages had higher USP7 expression. Knockdown of USP7 revealed an inhibition of both M1 and M2 macrophage polarization. Inhibition of USP7 with P5091 resulted in the decreased expression of M1 polarization markers and phosphorylation of P65, but the increased expression of M2 polarization markers and phosphorylation of STAT6. In conclusion, USP7 is involved in regulating macrophage polarization in periodontitis and its inhibitor P5091 may contribute to the prevention of periodontitis.