Ligand-competent fractalkine receptor is expressed on exosomes

Eun Jeong Park; Phyoe Kyawe Myint; Michael G Appiah; Patsorn Worawattananutai; Janjira Inprasit; Onmanee Prajuabjinda; Zay Yar Soe; Arong Gaowa; Eiji Kawamoto; Motomu Shimaoka

doi:10.1016/j.bbrep.2021.100932

Ligand-competent fractalkine receptor is expressed on exosomes

Biochem Biophys Rep. 2021 Feb 2:26:100932. doi: 10.1016/j.bbrep.2021.100932. eCollection 2021 Jul.

Affiliations

¹ Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan.
² Department of Emergency and Disaster Medicine, Mie University Graduate School of Medicine, Tsu, Mie, 514-8507, Japan.

Abstract

Expression of chemokine receptor CX3CR1 is reportedly restricted to several cell types including natural killer cells, cytotoxic T cells, monocytes, and macrophages. However, its expression and function on exosomes, which are nanosized extracellular vesicles known to act as mediators of intercellular communications, remain unclear. Here, we investigated CX3CR1 expression on exosomes isolated from various cell types. Although we found that all the exosomes tested in our study highly expressed CX3CR1, this chemokine receptor was expressed only inside, but barely on, their source cells. Moreover, exosomal CX3CR1 was capable of binding soluble CX3CL1. Therefore, our study suggests that CX3CR1 is a novel and ligand-competent exosome receptor.

Keywords: CX3CR1; Chemokine; Chemokine receptor; Exosome; Fractalkine.