Fig. 8

The simulation of signaling pathway by which Exo/LPS pre-Exo modulates the immune response to allografts. Step 1: LPS was recognized by macrophages and induced upregulation of NLRP3, IL-1β and IL-18 expression through the NF-κB signaling pathway. Step 2: After being endocytosed, LPS pre-Exo interacted with the NF-κB for preventing its activation and inhibited the expression of NLRP3 with suppressing the synthesis of NLRP3 inflammasome and subsequent production of IL-1β and IL-18. Step 3: In the subsequent immune response, following administration of LPS pre-Exo which induced alternation in the polarization of macrophages for expanding the ratio of M2 with CD86⁺ macrophages. Taken together, the functional outcome is to suppress the innate immune response