Objective:To investigate the effects of Bcl3 gene knockout on the composition of spleen immune cells and antitumor ability of mice.Methods:Bcl3 gene knockout mice (Bcl3 -/-) were established by CRISPR/Cas9 genome editing technology. Blood routine test and flow cytometry were used to detect the immune cell composition in Bcl3 -/- mice. Lung metastasis models were established by injecting mice with B16F10 melanoma cells. The number of tumor nodules in lung and the survival time of mice were used to assess the antitumor ability of wild-type (WT) and Bcl3 -/- mice. Results:Bcl3 -/- mice were successfully bred to a strain with normal growth rate and normal breeding performance. Furthermore, no embryonic death occurred. Compared with WT mice, Bcl3 -/- mice showed splenomegaly and a significant increase in the number of spleen immune cells ( P<0.05). The counts and percentages of platelets and neutrophils in Bcl3 -/- mice were significantly lower than those in WT mice. The proportion of CD19 + B cells showed no significant change, while the proportions of CD3 + T cells and T cell subsets (CD4 + , CD8 + , Treg) increased significantly ( P<0.05). The proportions of NK cells (NK1.1 + ) and neutrophils (Gr1 + ) decreased ( P<0.05), while no significant change in the proportion of DC (CD11b + ) was observed. There were a large number of tumor nodules formed by melanoma cells in the lung of Bcl3 -/- tumor bearing mice, and their survival time was shortened dramatically. Conclusions:Knockout of Bcl3 gene affected the development, differentiation and function of immune cells, thereby reducing the antitumor ability of mice.

Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1 (NDM-1) are a type of newly discovered antibioticresistant bacteria. The rapid pandemic spread of NDM-1 bacteria worldwide (spreading to India, Pakistan, Europe, America, and Chinese Taiwan) in less than 2 months characterizes these microbes as a potentially major global health problem. The drug resistance of NDM-1 bacteria is largely due to plasmids containing the blaNDM-1 gene shuttling through bacterial populations. The NDM-1 enzyme encoded by the blaNDM-1 gene hydrolyzes β-lactam antibiotics, allowing the bacteria to escape the action of antibiotics. Although the biological functions and structural features of NDM-1 have been proposed according to results from functional and structural investigation of its homologues, the precise molecular characteristics and mechanism of action of NDM-1 have not been clarified. Here, we report the three-dimensional structure of NDM-1 with two catalytic zinc ions in its active site. Biological and mass spectroscopy results revealed that D-captopril can effectively inhibit the enzymatic activity of NDM-1 by binding to its active site with high binding affinity. The unique features concerning the primary sequence and structural conformation of the active site distinguish NDM-1 from other reported metallo-β-lactamases (MBLs) and implicate its role in wide spectrum drug resistance. We also discuss the molecular mechanism of NDM-1 action and its essential role in the pandemic of drug-resistant NDM-1 bacteria. Our results will provide helpful information for future drug discovery targeting drug resistance caused by NDM-1 and related metallo-β-lactamases.
Amino Acid Sequence ; Anti-Bacterial Agents ; metabolism ; Binding Sites ; Captopril ; chemistry ; pharmacology ; Catalytic Domain ; Crystallography, X-Ray ; Drug Resistance, Bacterial ; Enterobacteriaceae ; enzymology ; Molecular Sequence Data ; Sequence Alignment ; Sequence Homology, Amino Acid ; beta-Lactamases ; chemistry ; metabolism

Objective: To investigate the effects of human adult T lymphoblastic leukemia virus typeⅠ (HTLV-1) infection on the production of reactive oxygen species (ROS) and mitochondrial damage in host cells. Methods: A cell model of HTLV-1 infection was established by co-culturing HTLV-1-positive cell line MT2 with HeLa cells. ROS, mitochondrial membrane potential (MMP) and total mitochondria were detected using specific fluorescence probe labeling method. Cell apoptosis was detected by Annexin V-FITC/PI method. Western blot was performed to detect viral proteins Tax and p19, as well as mitochondrial proteins TIM23 and TOM20. After the treatment of MT2 cells with different concentrations of reverse transcription inhibitors (ZDV), relative viral loads were detected by quantitative real-time PCR and Western blot, and the mass of mitochondria was analyzed by flow cytometry. Results: After co-culturing HeLa cells with MT2 cells for 24 h, the ROS level in host cells increased without obvious cell apoptosis, while the mitochondrial membrane potential, mitochondrial protein expression and total mitochondria decreased significantly. When the replication of HTLV-1 in MT2 cells was inhibited by ZDV, the ROS level and total mitochondria increased. Conclusions HTLV-1 infection can cause oxidative stress in host cells, resulting in mitochondrial damage. Autophagy might be activated to degrade mitochondrial damage and maintain cell homeostasis during the infection.