Journal: Frontiers in Immunology
Article Title: Toll-Like Receptor- and Protein Kinase R-Induced Type I Interferon Sustains Infection of Leishmania donovani in Macrophages
doi: 10.3389/fimmu.2022.801182
Figure Lengend Snippet: Neutrophil elastase and PKR are required for the induction of anti-inflammatory genes in infected macrophages. (A) Nuclear extracts were obtained from C57BL6 macrophages infected for 2, 6, or 24 h with stationary-phase promastigotes of L. donovani at a 10:1 parasite:macrophage ratio. The nuclear extracts were processed for Western blot analysis with antibodies to IRF3, as well as nuclear lamin for the loading control. Macrophages incubated in medium alone were used as the baseline control (Ctrl). Poly I:C was used at 25 µg/ml. In (D) , total lysates were obtained from C57BL/6 macrophages infected for 1 h with stationary-phase promastigotes of L. donovani at a 10:1 parasite:macrophage ratio and processed for Western blot with antibodies to phospho-PKR, as well as actin for the loading control. Where indicated, monolayers were pre-treated with 100 nM of the TLR4 inhibitor, TAK-242 or with 10 µM of neutrophil elastase inhibitor (NEI) before infection. Total RNA was extracted from L. donovani -infected macrophages from (B, C, E) C57BL/6 and ela2 -/- mice or (F) 129Sv/Ev and pkr -/- mice. Thioglycolate-recruited peritoneal macrophages were infected with stationary-phase promastigotes of L. donovani wild-type or L. donovani expressing ISP2 ( L.d:ISP 2) at a 10:1 parasite:macrophage ratio for 2 h, cultures were washed, and RNA was extracted or cultures were incubated in RPMI-BSA until 6 h before extraction. cDNA was made and used as a template in qPCR for the determination of the relative mRNA levels for IL10, OASL2, SOD1, and PKR as indicated. The experiment was repeated 2 independent times. The graphs show representative experiments, with the means ± SD of the triplicate technical replicates. Statistical significance was assessed using one-way ANOVA with Bonferroni posttest. * p < 0.05, ** p < 0.01, *** p < 0.001.
Article Snippet: In the experiments of receptor neutralization, 10 μg/ml anti-mouse TLR4 neutralizing antibodies (CD284/MD2 complex clone MTS510; Thermo Fisher Scientific) or 10 μg/ml IgG (IgG2aK control clone eBR2a; Thermo Fisher Scientific) were incubated for 30 min with the macrophages in RPMI-10% FCS and then washed twice before infection with the parasites in RPMI-0.1% BSA at 37°C and 5% CO 2 .
Techniques: Infection, Western Blot, Control, Incubation, Expressing, Extraction