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. 2020 May 24;9(5):1307. doi: 10.3390/cells9051307

Figure 3.

Figure 3

EVs containing IL-6R induces STAT3 (Signal Transducer and Activator of Transcription 3) phosphorylation (Tyr705). (A) Schematic presentation of full-length IL-6R (IL-6R fl) and a variant lacking the stalk region of the IL-6R (IL-6R Δ317-362). This variant was previously shown to be inactive with regard to signal transduction [38]. (B) Western blot analysis of cell lysate and isolated EVs carrying the full-length IL-6R (IL-6R fl) and the IL-6R missing the stalk region (IL-6R Δ317-362). The deletion variant migrates at a lower molecular mass, due to the removal of the stalk region. (C) Timeline experiment in BaF/3 gp130 expressing cells. These cells depend on the IL-6R and IL-6 for Stat3 phosphorylation (pSTAT3). HyperIL-6 (HyIL6), a chimeric protein of IL-6 and soluble IL-6R, was used as a positive control. Only EVs carrying the wild-type (WT) IL-6R (IL-6R fl) induces STAT3 phosphorylation. (D) Quantification of five independent experiments (as in C) reveals a significant increase in pSTAT3 signal in BaF/3 gp130 cells incubated with EVs carrying WT IL-6R (IL-6R fl) compared to BaF/3 gp130 cells incubated with EVs expressing the IL-6R Δ317-362 after 60 min (n = 5, statistical significance was tested using two-way analysis of variance (ANOVA), significance assumed for ** = P < 0.01).