Journal: Frontiers in Immunology
Article Title: Upregulation of TREM2 expression in M2 macrophages promotes Brucella abortus chronic infection
doi: 10.3389/fimmu.2024.1466520
Figure Lengend Snippet: TREM2 enhances B. abortus survival by suppressing M2 intracellular ROS production. (A) RAW-M2-NT, RAW-M2-ΔTREM2, RAW-M2-Vector, or RAW-M2-TREM2+ cells were infected with B. abortus (MOI = 100), respectively. Intracellular numbers of B. abortus at the indicated times were analyzed by CFU assay. (B) BMDM-M2 macrophages were infected with B. abortus (MOI = 100) in the presence of DMSO or Baf A1 (100 nM) or mock treatment. The intracellular numbers of B. abortus were analyzed by CFU assay at the indicated time points. CFU was expressed as means ± standard deviations from two independent experiments. *P <0.05 vs. Baf A1. BMDM-M2 were infected with B. abortus (MOI = 100) for 8 h, 24 h, or 48 h in the presence of DMSO or Baf A1 (100 nM) or mock treatment. The concentration of nitric oxide (NO) in the culture supernatant collected was measured using Griess reagent (C) . The intracellular ROS production was detected by DCFH-DADHE. The graph demonstrates the SEM and mean of changes in production of intracellular ROS compared with the uninfected cells (as 100%) (D) . The mitochondria ROS (mROS) concentrations were detected by Mito-SOX. The graph demonstrates the SEM and mean of changes in production of mROS compared with the uninfected cells (as 100%) (top panel), representative images of Mito-SOX red (mitochondrial ROS marker) staining of Mock, DMSO and Baf A1 (48 h) (bottom panel). Scale bar = 50 µm (E) . DMSO-pretreated BMDM-M2 were infected with B. abortus (MOI = 100), or Baf A1 (100 nM)-pretreated BMDM-M2 were infected with B. abortus (MOI = 100) in the presence or absence of 10 μM DPI (F) or in the presence or absence of 10 μM Mito-TEMPO (G) , and then bacterial survival was analyzed at the indicated times by CFU assay. *P <0.05 vs. Baf A1 alone. There is no significance (NS) between Baf A1 treatment and Baf A1 plus Mito-TEMPO. (H) Isotype pretreated or anti-TREM2 antibody (5 ug/ml) pretreated BMDM-M2 macrophages were infected with B. abortus (MOI = 100) in the presence of Mock or 10 μM Mito-TEMPO, and then bacterial survival at 48 h post-infection was analyzed by CFU assay. All results were analyzed using a one-way ANOVA followed by Bonferroni correction. P-values <0.05 were considered significant (*, P <0.05). NS indicates no significance.
Article Snippet: Anti-TREM2 neutralizing antibody (FAB17291A), mouse rIFN- γ (Cat: NP_032363), and mouse rIL-4 (Cat: P07750) were purchased from R&D Systems (Shanghai, China).
Techniques: Plasmid Preparation, Infection, Colony-forming Unit Assay, Concentration Assay, Marker, Staining