P2Y2 Receptor Induces L. amazonensis Infection Control in a Mechanism Dependent on Caspase-1 Activation and IL-1β Secretion
P2Y2R selective agonist 2-thio-UTP improves host resistance against L. amazonensis. (a) Schematics showing the animal model of in vivo experiments. BALB/c mice () were subcutaneously injected in the footpad with 106 promastigotes (L. amazonensis at stationary phase). From 7 days postinfection (d.p.i.), mice were treated with 10 μM 2-thio-UTP in 20 μL PBS and injected into the infected footpad twice a week for 3 weeks (six doses). (b–d) Animals were euthanized 26 d.p.i., and the footpads and popliteal lymph nodes were removed and used for further analysis. (b) Parasitic loads in the footpads and lymph nodes (c) were determined using a limiting dilution assay (LDA). (d) Leukocyte numbers from popliteal lymph nodes. (e) Schematics showing the design of in vitro experiments. BALB/c (f, g) and C57Bl/6 (WT) (h, i) macrophages infected for 48 h were treated for 30 min with UTP (1–100 μM UTP) (f–h) or 2-thio-UTP (0.025–1 μM) (g–i). After 30 h, cells were fixed, stained with the panoptic kit, and observed with light microscopy. The effect of treatments on infection was quantified by determining the “infection index” ; normalized to the untreated), by direct counting under the light microscope. Data represent of three independent experiments performed in triplicate, with pools of cells from four animals each experiment. relative to the untreated group (one-way analysis of variance followed by Tukey’s test).
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