Single-Particle Tracking of Human Immunodeficiency Virus Type 1 Productive Entry intoHuman Primary Macrophages.

Li Q, Li W, Yin W, Guo J, Zhang ZP, Zeng D, Zhang X, Wu Y, Zhang XE, Cui Z.

ACS Nano. 2017 Apr 25;11(4):3890-3903. doi: 10.1021/acsnano.7b00275. Epub 2017 Apr 6.

Abstract

Macrophages are one of the major targets of human immunodeficiency virus (HIV-1), but the viral entry pathway remains poorly understood in these cells. Noninvasive virus labeling and single-virus tracking are effective tools for studying virus entry. Here, we constructed a quantum dot (QD)-encapsulated infectious HIV-1 particle to track viral entry at a single-particle level in live human primary macrophages. QDs were encapsulated in HIV-1 virions by incorporating viral accessory protein Vpr-conjugated QDs during virus assembly. With the HIV-1 particles encapsulating QDs, we monitored the early phase of viral infection in real time and observed that, during infection, HIV-1 was endocytosed in a clathrin-mediated manner; the particles were translocated into Rab5A-positive endosomes, and the core was released into the cytoplasm by viral envelope-mediated endosomal fusion. Drug inhibition assays verified that endosome fusion contributes to HIV-1 productive infection in primarymacrophages. Additionally, we observed that a dynamic actin cytoskeleton is critical for HIV-1 entry and intracellular migration in primarymacrophages. HIV-1 dynamics and infection could be blocked by multiple different actin inhibitors. Our study revealed a productive entrypathway in macrophages that requires both endosomal function and actin dynamics, which may assist in the development of inhibitors to block the HIV entry in macrophages.