Mechanism of USP7 positively regulates inflammatory response to EV71 infection by inhibiting K48 ubiquitination of MDA5
10.3969/j.issn.1000-484X.2025.10.015
- VernacularTitle:USP7抑制MDA5的K48位泛素化正向调控EV71感染炎症反应的机制研究
- Author:
Qianyu PAN
1
;
Xiaoman LIN
;
Ying SUN
;
Hong YANG
;
Jun MENG
Author Information
1. 南方医科大学公共卫生学院,广州 510515
- Publication Type:Journal Article
- Keywords:
Enterovirus 71;
Ubiquitin specific protease 7;
Melanoma differentiation-associated gene 5;
Innate immunity
- From:
Chinese Journal of Immunology
2025;41(10):2392-2396
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the effect and mechanism of USP7 on immune and inflammatory response of EV71 infection.Methods:THP-1 cells were induced to differentiate into t-Mφ cells by PMA,cells were treated by targeted USP7 inhibitor P22077,and divided into DMSO control group and P22077 experimental group,and infected with EV71.ELISA was used to detect supernatant concentration of IL-6,CCL3,TNF-α of cells separately.RT-qPCR was used to detect RNA expression of EV71-VP1,plaque test was used to detect virus titer in cell supernatant.Western blot was used to detect expressions and phosphorylation of molecules related to innate immune signaling pathway.Full-length plasmid Myc-USP7 and Flag-MDA5 were constructed and transfected into HEK293T cells,and Co-IP was used to detect external interaction between USP7 and MDA5 with Myc antibody and Flag antibody,respectively.Infected t-Mφ cells with EV71,and Co-IP detection of their interaction by USP7 and MDA5 antibodies,respectively.t-Mφ cells of DMSO control group and P22077 experimental group were infected with EV71,CHX test was used to detect expression of MDA5 and downstream related molecules.Transfected Flag-MDA5,Myc-USP7,HA-Ub or HA-K48 plasmids,Co-IP detection of ubiquitination and ubiquitination types of MDA5 regulated by USP7 with Flag antibody.Co-IP detection of MDA5 ubiquitination types regulated by USP7 in t-Mφ cells by using MDA5 antibodies.Results:After infected with EV71 and inhibited of USP7,mRNA and protein expres-sions of IL-6,CCL3 and TNF-α were decreased(P<0.05),while EV71 replication(P<0.05),and titer increased;expression of MDA5,and activation of p-IKKα/β,p-IκBα and p-p65 in innate immunity signal pathway decreased.Interaction between USP7 and MDA5 could inhibit MDA5 degradation by inhibiting K48 ubiquitination of MDA5.Conclusion:USP7 stabilizes MDA5 expression by inhibiting K48 ubiquitination of MDA5,thereby positively regulating EV71 infection immunity and inflammatory response.
