Extracellular Vesicles with Exosome-like Features Transfer TLRs between Dendritic Cells.

Accumulating evidence shows that extracellular vesicles (EVs) secreted by immune cells play an important role in intercellular communication. In the current report, we show that EVs released from wild-type bone marrow-derived dendritic cells (BMDCs) transfer TLRs to TLR4-knockout (TLR4KO) BMDCs and increase cellular responsiveness to LPS in recipient cells. The transferred EVs have exosomal characteristics and induce the activation of NF-κB signaling pathways in recipient cells. We further show that BMDC-derived EVs can promote LPS-induced inflammation in TLR4KO mice in vivo. These results indicate that functional TLR4 can be transferred from wild-type to TLR4KO BMDCs through exosome-like EVs.