Journal: Immunity
Article Title: Inhibition of transcription factor NFAT activity in activated platelets enhances their aggregation and exacerbates gram-negative bacterial septicemia
doi: 10.1016/j.immuni.2021.12.002
Figure Lengend Snippet: (A) Whole blood from mice treated, or not, with 4 mg/kg of FK506 for 14 days was stimulated, or not, with PAR4-AP (100 μM). The formation of complexes between platelets and neutrophils was analyzed by cytofluorimetry. Results show the MFI for the platelet marker CD41 on neutrophils, identified as Ly6G+CD11b+ cells. Data represent mean ± SEM. n ≥ 3 independent experiments. (B) Platelet-neutrophil complex formation was analyzed by ImageStream. Platelets treated, or not, with 1 μM FK506 for 1 h and identified with different fluorochromes, were washed, mixed with the blood from platelet-depleted mice, and stimulated (PAR4-AP), or not (Unstim), with PAR4-AP (25 μM). The percentage of neutrophils (identified as Ly6G+ cells in the whole blood) that did not bind any platelets (0), or that bound 1 or 2 platelets (1–2), or 3 or more platelets (>3) was measured for both platelets pretreated (FK-506) or not (NT) with FK506. Data represent mean ± SEM. n ≥ 3 independent experiments. (C) PRP was pretreated, or not, with 1 μM FK506 for 1 h and stimulated with PAR4-AP (150 μM) for 5 min. PAR4-AP-activated platelets were then used to induce NETosis. Histograms represent the percentage of neutrophils positive for the citrullinated histone H3 (left). Each dot represents an independent test. A representative image of NET released by neutrophils is shown (right). Scale bars, 10 μm. (D) Murine PRP was pretreated, or not, with 1 μM FK506 for 1 h and then stimulated with different concentration of PAR4-AP (150 and 100 μM). P-selectin exposure was analyzed by cytofluorimetry and P-selectin MFI is shown. Data represent mean ± SEM. n ≥ 3 independent experiments. (E) Neutrophils were stimulated as in (C) in the presence of the anti-P-selectin antibody or respective isotype control. Data represent mean ± SEM. n ≥ 3 independent experiments. One-way ANOVA (A, D, and E), two-way ANOVA (B), or unpaired two-tailed t test (C) were used for statistics. n.s., not significant (p > 0.05), *p < 0.05, **p < 0.01, and ****p < 0.0001. See also Figure S4.
Article Snippet: PAR4-AP , MedChemExpress , Cat# HY-P1309.
Techniques: Marker, Concentration Assay, Control, Two Tailed Test