Figure 4.

Targeted IL-27 Utilizes Both Paracrine and Autocrine Signaling

(A) pepL-modified IL-27 utilizes autocrine mode of signaling. In the autocrine design, the plasmids expressing IL-27 were delivered along with a reporter plasmid (STAT1-luc). The IL-27 C-term pepL (IL-27.pepL) allows anchoring of cytokine to the overexpressed targeting receptors (IL-6Rα). The cytokine is expressed and acts on the IL-27R to mediate STAT1 signaling. (B) PepL enhances IL-27 signaling also in a paracrine mode. In the paracrine design, either differentiating osteoblast (OB, MC3T3E1-14 day 4) or epithelial cells (TC2r) were transfected with STAT1-luc, and then mixed with the other cell type expressing IL-27.ns, IL-27.pepL, or empty vector control. In order to have an effect, IL-27.pepL had to be secreted from one cell type and bind to the other cell type (bearing STAT1-luc) to induce signaling. In the autocrine design, pSTAT1-luc and pIL-27s were cotransfected. The paracrine signaling effect can be blocked by pretreatment (30 min) with an anti-IL-6Rα blocking antibody (Ab). ∗p < 0.04 versus control, #p < 0.05 versus IL-27.ns. ∗p < 0.05 versus ctrl MCS or no cell coculture (comix); #p < 0.05 versus 27.ns; $p < 0.05 AB 27L versus 27L. Data is expressed as mean +- the standard deviation.