The Role Of Ubiquitination Enzyme UCHL1 In Fc Receptor-mediated Monocyte Training Immunity

In the previous study of the laboratory,we found that immune complexes can induce monocytes to produce similar sensitivity enhancement states,namely,training immunity.After dealed with coated-IVIG monocytes to accept external stimuli,such as LPS,Zymosan,etc.,can increase the sensitivity of mononuclear cells.Combined with the fact that autoimmune diseases are associated with autoantibodies and immune complexes,studies on the mechanism of immune complex-induced monocyte acclimation may provide a basis for explaining the new mechanism of autoimmune disease.In this study,the results of RNA-seq(RNA-seq)in the coated-IVIG treatment group and the control group were analyzed by differential gene enrichment analysis and protein interaction analysis.The results showed that the differentiation genes in the acclimation were significantly enriched in the ubiquitin-proteasome pathway(hsa04120: Ubiquitin mediated proteolysis)pathway.The enhancement of monocytes sensitivity is mainly mediated by TNF-α and IL-6,which are mediated by NF-κB,and the ubiquitin-proteasome pathway is closely related to NF-κB signaling pathway,suggesting that the cation of c-IVIG may be a UPS that affects the NF-κB signaling pathway.One of the important components of the ubiquitinase pathway is the ubiquitinating enzyme(DUBs),which plays a major role in maintaining the free ubiquitin level in the cells.The stability of free ubiquitin level is an important prerequisite for the normal regulation of ubiquitin protease system.We screened out a number of ubiquitinating enzymes with large changes in gene expression from the result of RNA-seq.The NF-κB signal pathway was constructed in 293 T cells and overexpressed several DUBs were identified to determine these enzyme on the role of NF-κB signaling pathway.Then we selected UCHL1 for study.UCHL1 has both ubiquitin hydrolase and ubiquitin ligase activity.This dual function of UCHL1 distinguishes it from other DUBs,which makes DUBs became a special target to study the function.We investigated the effect of UCHL1 on NF-κB signaling pathway by overexpressing and knocking down the expression of UCHL1 in 293 T cells.The results showed that UCHL1 played a positive role in regulating NF-κB signaling pathway.And study the effect of UCHL1 on the activity of NF-κB signaling pathway through the activity of its hydrolase or ligase by mutating the enzyme activity sites of UCHL1 ubiquitin hydrolase and ubiquitin ligase.The results showed that the regulatory effect of UCHL1 on activation of NF-κB signaling pathway was significantly inhibited under the condition of UCHL1 ubiquitin hydrolase activity,whitch indicates that the activity of the hydrolase plays a decisive role in the effect of UCHL1 on NF-κB signaling pathways.UCHL1 may function upstream of the p65-NF-κB factor,but downstream of the NEMO/IKK complex,thus affecting the activation of NF-κB signaling pathway.Based on the above results,we believe that autoimmune diseases in patients with immune complexes can be domesticated monocyte,and enhance its sensitivity.This role is through the ubiquitination enzyme UCHL1 regulation of NF-κB signaling pathway activation,leading to the occurrence and progress of the disease,which provides a theoretical basis for the treatment of autoimmune diseases.