Figure 1.

As part of the intercellular endocytic communication pathway, TLR-binding microRNA transmitted via extracellular vesicles serve adaptive and maladaptive stress responses. Environmental stress (1) promotes secretion of extracellular vesicles and microRNA, (self-) antigen and danger-associated molecule release (2). After uptake by innate immune cells, specific GU-rich extracellular vesicle-encapsulated microRNA sequences can stimulate TLR-7/8 signaling in the endosome of recipient cells. Subsequent activation of the NF-κB pathway exacerbates inflammation through cytokine secretion, expression of co-stimulatory molecules (3) and self-induction of TLR-binding microRNA expression and extracellular vesicle secretion (4).