Astragalus polysaccharide promotes latent HIV-1 reactivation via exosome-mediated modulation of the PI3K/AKT/NF-κB axis.

Aim: Reactivating the human immunodeficiency virus type 1 (HIV-1) reservoir is one of the key avenues toward a functional cure for acquired immunodeficiency syndrome (AIDS). However, clinically effective and safe latency-reversing agents remain lacking. Exosomes play an important role in regulating latent HIV-1. This study elucidates the capacity of exosomes derived from Astragalus polysaccharide (APS)-primed HIV-1 reservoir cells, J-Lat Full Length 10.6 (hereafter abbreviated as J-Lat 10.6), termed APS-Lat-EXO, to reactivate latent HIV-1 and investigates the underlying mechanisms. Methods: J-Lat 10.6 cells were used as a model of HIV-1 latency. Cells were exposed to APS, and exosomes derived from APS-treated cells (APS-Lat-EXO) and untreated cells (Lat-EXO) were isolated. These exosomes were subsequently applied to J-Lat 10.6 cells. Latency reactivation was evaluated by flow cytometry, Enzyme-Linked ImmunoSorbent Assay (ELISA), and real-time quantitative polymerase chain reaction (RT-qPCR), which measured green fluorescent protein (GFP⁺) cell proportions, p24 (the HIV-1 capsid protein) levels, and group-specific antigen (Gag)/long terminal repeat (LTR) expression, respectively. Proteomic and microRNAs (miRNAs) analyses were performed to compare APS-Lat-EXO and Lat-EXO, and Western blot assays were used to assess activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Results: APS-Lat-EXO significantly reactivated latent HIV reservoirs in both J-Lat 10.6 cells and peripheral blood mononuclear cells from HIV-1-infected individuals, as indicated by increased GFP⁺ cell proportions, elevated p24 levels, and upregulated Gag/LTR expression. Proteomic and miRNA microarray analyses revealed notable differences between APS-Lat-EXO and Lat-EXO in protein profiles and miRNA composition. Functional enrichment analyses showed that differentially expressed proteins in APS-Lat-EXO were enriched in the PI3K/AKT pathway, while differentially expressed miRNAs were linked to NF-κB. In vitro experiments confirmed that APS-Lat-EXO reactivated latent HIV-1 via the PI3K/AKT/NF-κB pathway. Conclusion: This study shows that APS-Lat-EXO is capable of inducing reactivation of latent HIV-1 through activation of the PI3K/AKT/NF-κB axis, highlighting its potential as a bio-derived latency-reversing candidate within the shock-and-kill framework.