Vpr counteracts the restriction of LAPTM5 to promote HIV-1 infection in macrophages

Abstract

The HIV-1 accessory proteins Vif, Vpu, and Nef can promote infection by overcoming the inhibitory effects of the host cell restriction factors APOBEC3G, Tetherin, and SERINC5, respectively. However, how the HIV-1 accessory protein Vpr enhances infection in macrophages but not in CD4+ T cells remains elusive. Here, we report that Vpr counteracts lysosomal-associated transmembrane protein 5 (LAPTM5), a potent inhibitor of HIV-1 particle infectivity, to enhance HIV-1 infection in macrophages. LAPTM5 transports HIV-1 envelope glycoproteins to lysosomes for degradation, thereby inhibiting virion infectivity. Vpr counteracts the restrictive effects of LAPTM5 by triggering its degradation via DCAF1. In the absence of Vpr, the silencing of LAPTM5 precisely phenocopied the effect of Vpr on HIV-1 infection. In contrast, Vpr did not enhance HIV-1 infection in the absence of LAPTM5. Moreover, LAPTM5 was highly expressed in macrophages but not in CD4+ T lymphocytes. Re-expressing LAPTM5 reconstituted the Vpr-dependent promotion of HIV-1 infection in primary CD4+ T cells, as observed in macrophages. Herein, we demonstrate the molecular mechanism used by Vpr to overcome LAPTM5 restriction in macrophages, providing a potential strategy for anti-HIV/AIDS therapeutics.

Neuropilin-1, a myeloid cell-specific protein, is an inhibitor of HIV-1 infectivity

“…The CD4 + T cells were stimulated by adding CD3/CD28 activator magnetic beads (Invitrogen) to the culture medium for 2 d with 50 U/mL interleukin (IL)-2 (Biomol). The isolation and culturing of monocytes, MDMs, and MDDCs were performed ( 28 , 29 ). MDMs were generated by stimulating monocytes with 10 ng/mL recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF; R&D) and 50 ng/mL recombinant human macrophage colony-stimulating factor (M-CSF; R&D) for 7 d. MDDCs were generated by incubating CD14-purified monocytes in IMDM medium (Gibco) supplemented with 10% FBS, 2 mM l -glutamine, 100 IU/mL penicillin, 100 mg/mL streptomycin, 10 mM Hepes, 1% nonessential amino acids, 1 mM sodium pyruvate, 10 ng/mL GM-CSF, and 50 ng/mL IL-4 (Miltenyi Biotec).…”

“…The shRNA-mediated silencing of NRP-1 (RHS4430-200289197 or RHS4430-200215106 targeting open reading frame; RHS4430-200222352 targeting 3′-UTR) or control (catalog no. RHS4346) was achieved by introducing a microRNA-adapted shRNA lentivirus into the THP-1 cells, MDMs, and MDDCs ( 28 , 29 ). In summary, the freshly isolated monocytes were treated with Vpx and transduced with an shRNA lentivirus.…”

“…Mouse NIH 3T3 cells were infected with MLV for 24 h, and genomic DNA was extracted from the cells to quantify late reverse-transcript product using qPCR with specific primers for MLV 5′-CGTCAGCGGGGGTCTTTC-3′ and 5′-CTGGGCAGGGGTCTCCCG-3′ ( 29 , 31 ).…”

Linking a nuclear lncRNA to cytoplasmic lysosome integrity and cell death

“…Whether LCDR can be developed as a predictive biomarker for cancer diagnosis and targeted cancer therapy will be an ultimate goal long to reach. Together with a recent report on LAPTM5 restriction of HIV infection in macrophages ( 18 ), the paradigm-shifting findings by Yang et al. provide an excellent example bridging a nuclear lncRNA to cytoplasmic control of lysosome integrity and metabolism for cell homeostasis and antipathogen defense, a next frontier for the lncRNA field.…”

LAPTM5 Restricts HIV-1 Infection in Dendritic Cells and Is Counteracted by Vpr

“…Similarly, as Vpr increases viral envelope protein (Env) levels in primary macrophages ( 3 ), Vpr has also been reported to promote HIV-1 infection in dendritic cells by enhancing Env levels ( 4 ). Recently, we have demonstrated that lysosomal-associated transmembrane protein 5 (LAPTM5) is responsible for the long-sought anti-HIV-1 host restriction factor in primary macrophages suppressed by Vpr ( 5 ). We also observed high LAPTM5 expression levels in monocyte-derived dendritic cells (MDDCs), prompting us to investigate the relationship between Vpr and LAPTM5 in MDDCs and explore whether Vpr also counteracts the restriction of LAPTM5 to promote HIV-1 infection in dendritic cells.…”