Exosomal release of the virus-encoded chemokine receptor US28 contributes to chemokine scavenging
Maarten P. Bebelman,
Irfan M. Setiawan,
Nick D. Bergkamp,
Jeffrey R. van Senten,
Caitrin Crudden,
Jan Paul M. Bebelman,
Frederik J. Verweij,
Guillaume van Niel,
Marco Siderius,
D. Michiel Pegtel,
Martine J. Smit
Affiliations
Maarten P. Bebelman
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands; Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
Irfan M. Setiawan
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
Nick D. Bergkamp
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
Jeffrey R. van Senten
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
Caitrin Crudden
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands; Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
Jan Paul M. Bebelman
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
Frederik J. Verweij
Division of Cell Biology, Neurobiology and Biophysics, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
Guillaume van Niel
Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266 Université de Paris, Paris, France
Marco Siderius
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
D. Michiel Pegtel
Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
Martine J. Smit
Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands; Corresponding author
Summary: The human cytomegalovirus (HCMV)-encoded chemokine receptor US28 contributes to various aspects of the viral life cycle and promotes immune evasion by scavenging chemokines from the microenvironment of HCMV-infected cells. In contrast to the plasma membrane localization of most human chemokine receptors, US28 has a predominant intracellular localization. In this study, we used immunofluorescence and electron microscopy to determine the localization of US28 upon exogenous expression, as well as in HCMV-infected cells. We observed that US28 localizes to late endosomal compartments called multivesicular bodies (MVBs), where it is sorted in intraluminal vesicles. Live-cell total internal reflection fluorescence (TIRF) microscopy revealed that US28-containing MVBs can fuse with the plasma membrane, resulting in the secretion of US28 on exosomes. Exosomal US28 binds the chemokines CX3CL1 and CCL5, and US28-containing exosomes inhibited the CX3CL1-CX3CR1 signaling axis. These findings suggest that exosomal release of US28 contributes to chemokine scavenging and immune evasion by HCMV.
