Elucidation of molecular mechanisms underlying host-pathogen interactions is important for control and treatment of infectious diseases worldwide. Within the last decade, mass spectrometry (MS)-based proteomics has become a powerful and effective approach to better understand complex and dynamic host-pathogen interactions at the protein level. Herein we will review the recent progress in proteomic analyses towards bacterial infection of their mammalian host with a particular focus on enteric pathogens. Large-scale studies of dynamic proteomic alterations during infection will be discussed from the perspective of both pathogenic bacteria and host cells.
Animals ; Bacteria ; chemistry ; pathogenicity ; Bacterial Infections ; microbiology ; pathology ; Bacterial Proteins ; isolation & purification ; metabolism ; Host-Pathogen Interactions ; Humans ; Mass Spectrometry ; Protein Processing, Post-Translational ; Proteomics

The cytotoxic effect targeting hepatitis B virus (HBV) infected hepatocytes from virus-specific cytotoxic T cells and the neutralizing antibodies secreted by virus-specific B cells play an important role in the immune control and elimination of HBV. In patients with chronic hepatitis B, the liver immune microenvironment usually presents a suppression state, and virus-specific immune cells are mostly exhausted. Studies on the interaction between HBV and host immunity during infection, especially the influence of various viral proteins on immune cell function, will contribute to understanding the mechanism of the chronicity of HBV infection, disease progression, and optimization of immunotherapy against HBV. The review summarized the suppressive effects of HBV viral proteins on the host innate immunity and adaptive immune system, to help us understanding the mechanism(s) relevant to the observation that a CHB patient with HBeAg loss and lower HBsAg level is more likley achieving functionall cure. and expect to provide new sights for accelerate virus clearance and achieve functional cure of chronic hepatitis B, by removing the HBV viral proteins and consequently, liberting host immune from suppression state.

Objective To investigate the ability and underlying mechanism of hepatitis B virus X protein (HBx)regulationofPolo-likekinase 1 (Plk1)expression.Methods The human HCC cell line HepG2 was transfected (transiently and stably) with an HBx plasmid expression vector (pCMV-HA-HBx) or empty plasmid vector (control),with and without expression plasmids with the Plk1 promoter.Effects on Plk1 expression were assessed by western blotting.Functional effects on the Plk1 promoter were assessed by luciferase reporter assay.Effects on the mRNA level of Plk1 in S phase HepG2 cells were assessed by quantitative real-time reverse transcriptase polymerase chain reaction.After blocking protein synthesis by treatment with cycloheximide (CHX),the turnover rate of Plk1 was assessed by western blotting.Lastly,the effect of HBx on cell cycle was assessed by flow cytometry.Results HBx did not increase the protein expression of Plk1 in non-synchronized HepG2 cells,but did significantly up-regulate the Plkt protein level in the synchronized S phase cells (P =0.026 and P =0.003,respectively).Ectopic expression of HBx did not increase the mRNA level of Plk1 in HepG2 cells,but did inhibit the degradation of Plk1,as evidenced by an increased half-life of Plk1 protein (from 30 to 90 minutes).The HBx-expressing HepG2 cells showed more trequent entry into the S or G2/M phase than the control cells (31.65％ vs.24.56％ or 9.43％ vs.4.47％,respectively) and less in the G0/G1 phase (decrease from 70.97％ to 58.92％ for the HBx-expressing HepG2 cells).Conclusion HBx is able to up-regulate the expression of Plk1 in HepG2 cells by a mechanism involving stabilization of the Plkl protein primarily in the S phase of the cell cycl.