CAGE-Seq Reveals that HIV-1 Latent Infection Does Not Trigger Unique Cellular Responses in a Jurkat T Cell Model

The cure for HIV-1 is currently stalled by our inability to specifically identify and target latently infected cells. HIV-1 viral RNA/DNA or viral proteins are recognized by cellular mechanisms and induce interferon responses in virus-producing cells, but changes in latently infected cells remain unknown. HIV(GKO) contains a green fluorescent protein (GFP) reporter under the HIV-1 promoter and a monomeric Kusabira orange 2 (mKO2) reporter under the internal elongation factor alpha (EF1α) promoter. This viral construct enables direct identification of both productively and latently HIV-1-infected cells. In this study, we aim to identify specific cellular transcriptional responses triggered by HIV-1 entry and integration using cap analysis of gene expression (CAGE). We deep sequenced CAGE tags in non-infected and latently and productively infected cells and compared their differentially expressed transcription start site (TSS) profiles. Virus-producing cells had differentially expressed TSSs related to T-cell activation and apoptosis compared to those of non-infected cells or latently infected cells. Surprisingly, latently infected cells had only 33 differentially expressed TSSs compared to those of non-infected cells. Among these, SPP1 and APOE were downregulated in latently infected cells. SPP1 or APOE knockdown in Jurkat T cells increased susceptibility to HIV(GKO) infection, suggesting that they have antiviral properties. Components of the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway, MLST8, 4EBP, and RPS6, were significant TSSs in productively infected cells, and S6 kinase (S6K) phosphorylation was increased compared to that in latently infected cells, suggesting that mTOR pathway activity plays a role in establishing the latent reservoir. These findings indicate that HIV-1 entry and integration do not trigger unique transcriptional responses when infection becomes latent. IMPORTANCE Latent HIV-1 infection is established as early as the first viral exposure and remains the most important barrier in obtaining the cure for HIV-1 infection. Here, we used cap analysis of gene expression (CAGE) to compare the transcriptional landscape of latently infected cells with that of non-infected or productively infected cells. We found that latently infected cells and non-infected cells show quite similar transcriptional profiles. Our data suggest that T cells cannot recognize incoming viral components or the integrated HIV-1 genome when infection remains latent. These findings should guide future research into widening our approaches to identify and target latent HIV-1-infected cells.