Table 1.
Patient characteristics and clinical data.
Fig 1.
PUUV-infected cells secrete IL-6.
HUVECs were infected with PUUV (MOI=1) and PBMCs were exposed to PUUV (MOI=3) for 24-72 h. Supernatants were assessed for IL-6, soluble gp130 (sgp130), and soluble IL-6R (sIL-6R) using ELISA. (A) Levels of IL-6 in supernatants of HUVECs (n=3) and (B) PBMCs (24-48 h, n=6, 72 h, n=2). (C) sgp130 levels in supernatants of HUVECs (n=3). (D) Levels of sgp130 (n=2) and sIL-6R (24-48 h, n=8, 72 h, n=6) in PBMC supernatants. Two-way ANOVA followed by Šídák’s multiple comparison test (factors; time after infection and condition (uninfected or PUUV-infected)). *, p<0.05, **, p<0.01.
Fig 2.
IL-6 trans-signaling activates endothelial cells and drives inflammation.
HUVECs were infected with PUUV (MOI=1) for 48 h and then treated with sIL-6R at the concentrations 31.25, 62.5, 125, 250, or 500 ng/ml for 24 h or left untreated. (A) Levels of IL-6 (n=5) and (B) CCL2 (n=3) in supernatants of uninfected and PUUV-infected HUVECs. (C) Representative histogram plot and (D) graph showing median ICAM-1 expression on infected and uninfected HUVECs (n=3). Symbols depict mean and error bars indicate SD. Two-way ANOVA followed by Dunnet’s or Šídák’s multiple comparison test (factors; level of sIL-6R added and condition (PUUV-infected or uninfected)). Black asterisks indicate significance when comparing PUUV to uninfected. Red asterisks indicate significance when comparing each sIL-6R-treated condition of PUUV-infected cells with untreated PUUV-infected cells. *, p<0.05; **, p<0.01; ***, p<0.001, ****, p<0.0001.
Fig 3.
IL-6 trans-signaling disrupts endothelial cell barrier functions during hantavirus-infection.
Uninfected and infected HUVECs were treated with sIL-6R at the concentrations 31.25, 62.5, 125, 250, or 500 ng/ml for 24 h or left untreated. (A) Immunofluorescence images showing expression of DAPI (blue), virus (red), and VE-cadherin (green). Representative images of three independent experiments are shown. (B) Transendothelial electrical resistance of uninfected (white symbol) and infected HUVECs (black symbol), with and without sIL-6R (n=3). Uninfected HUVECs treated with rIL-6 in addition to sIL-6R were used as control (grey symbol; n=3). Symbols depict mean and error bars indicate SD. Two-way ANOVA followed by Dunnet’s or Šídák’s multiple comparison test (factors; level of sIL-6R added and condition (uninfected, PUUV-infected, or uninfected + rIL-6)). Black asterisks indicate significance when comparing PUUV to uninfected. Red asterisks indicate significance when comparing each sIL-6R-treated condition of PUUV-infected cells with untreated PUUV-infected cells. *, p<0.05; **, p<0.01; ***, p<0.001, ****, p<0.0001.
Fig 4.
The plasma sIL-6R/sgp130 ratio is increased during acute HFRS and IL-6 trans-signaling potential correlate to severity.
Plasma levels of (A) IL-6, (B) sIL-6R, (C) IL-6:sIL-6R complex, and (D) sgp130 in controls (n=20) and acute and convalescent HFRS patients (n=28). (E) Ratio of plasma sIL-6R and sgp130 in controls and HFRS patients (n=27). (F) Correlation between sgp130 levels and number of interventions during acute HFRS (n=28). (G) Correlation between sgp130 levels and serum albumin (n=13). (H) Plasma sIL-6R/sgp130 ratio in patients with or without oxygen treatment (median, interquartile range). Wilcoxon signed-rank test (acute and convalescent HFRS patients, A-E); Kruskal-Wallis test (comparisons between controls and acute and convalescent HFRS patients, A-E); red line depicts median. Spearman’s rank correlation coefficient ( F-G). Mann Whitney test ( H); bars represent median. *, p<0.05; **, p<0.01; ***, p<0.001, ****, p<0.0001.