Targets the Host Ubiquitin-specific Protease, , Through the Effector Protein, TcpB, for Facilitating Infection of Macrophages

species are Gram-negative intracellular bacterial pathogens that cause the worldwide zoonotic disease brucellosis. can infect many mammals, including humans and domestic and wild animals. manipulates various host cellular processes to invade and multiply in professional and non-professional phagocytic cells. However, the host targets and their modulation by to facilitate the infection process remain obscure. Here, we report that the host ubiquitin-specific protease, USP8, negatively regulates the invasion of into macrophages through the plasma membrane receptor, CXCR4. Upon silencing or chemical inhibition of USP8, the membrane localization of the CXCR4 receptor was enriched, which augmented the invasion of into macrophages. Activation of USP8 through chemical inhibition of 14-3-3 protein affected the invasion of into macrophages. suppressed the expression of at its early stage of infection in the infected macrophages. Furthermore, we found that only live could negatively regulate the expression of , suggesting the role of secreted effector protein of in modulating the gene expression. Subsequent studies revealed that the effector protein, TIR-domain containing protein from , TcpB, plays a significant role in downregulating the expression of by targeting the cyclic-AMP response element-binding protein pathway. Treatment of mice with USP8 inhibitor resulted in enhanced survival of whereas mice treated with CXCR4 or 14-3-3 antagonists showed a diminished bacterial load. Our experimental data demonstrate a novel role of in the host defense against microbial intrusion. The present study provides insights into the microbial subversion of host defenses, and this information may ultimately help to develop novel therapeutic interventions for infectious diseases.