Astrocytes sustain long‐term productive HIV‐1 infection without establishment of reactivable viral latency

Abstract

The "shock and kill" HIV-1 cure strategy proposes eradication of stable cellular reservoirs by clinical treatment with latency-reversing agents (LRAs). Although resting CD4 T cells latently infected with HIV-1 constitute the main reservoir that is targeted by these approaches, their consequences on other reservoirs such as the central nervous system are still unknown and should be taken into consideration. We performed experiments aimed at defining the possible role of astrocytes in HIV-1 persistence in the brain and the effect of LRA treatments on this viral sanctuary. We first demonstrate that the diminished HIV-1 production in a proliferating astrocyte culture is due to a reduced proliferative capacity of virus-infected cells compared with uninfected astrocytes. In contrast, infection of non-proliferating astrocytes led to a robust HIV-1 infection that was sustained for over 60 days. To identify astrocytes latently infected with HIV-1, we designed a new dual-color reporter virus called NL4.3 eGFP-IRES-Crimson that is fully infectious and encodes for all viral proteins. Although we detected a small fraction of astrocytes carrying silent HIV-1 proviruses, we did not observe any reactivation using various LRAs and even strong inducers such as tumor necrosis factor, thus suggesting that these proviruses were either not transcriptionally competent or in a state of deep latency. Our findings imply that astrocytes might not constitute a latent reservoir per se but that relentless virus production by this brain cell population could contribute to the neurological disorders seen in HIV-1-infected persons subjected to combination antiretroviral therapy.

Insights into the Gene Expression Profiles of Active and Restricted Red/Green-HIV + Human Astrocytes: Implications for Shock or Lock Therapies in the Brain

“…Studies into the reactivation of latently infected HIV ϩ astrocytes with LRAs, including HDACi, PKC agonists, and proinflammatory mediators, have been enigmatic. Some have shown failure to reactivate HIV in astrocytes even in cells with prolonged viral gene expression (41,42), while others demonstrated HIV reactivation in various types of astrocytes (38,43). Our data also indicated significant activation in unsorted HIV ϩ astrocyte populations by vorinostat alone and in combination with IL-1␤.…”

Cell Death Is Counteracted by Mitophagy in HIV-Productively Infected Astrocytes but Is Promoted by Inflammasome Activation Among Non-productively Infected Cells

“…Astrocytes may represent an HIV cellular reservoir within the CNS because they are abundant and display a high frequency of infection ( 2 , 52 ). The HIV infection outcome on these cells is less clear, although a previous report has shown that they may survive or undergo cell death, dependent on viral replication or innocent bystander effects including mitochondrial dysregulation, respectively ( 3 ).…”

New Frontiers in Measuring and Characterizing the HIV Reservoir

“…Importantly, there is an increasing appreciation for the ability of tissue resident macrophages to self-renew and potentially serve as a long-lived reservoir of replication-competent virus (Gama et al, 2018;Roszer, 2018;Wong et al, 2019). In addition, neuroepithelial progenitor-derived astrocytes also harbor HIV provirus, though the replication competency and potential for reactivation of this virus in vivo is poorly understood (Al-Harti et al, 2018;Barat et al, 2018). HIV can infect multipotent hematopoietic CD34+ progenitor cells; however, in general during stable therapy detection of HIV DNA in this population is rare and no recovery of replication-competent virus has been demonstrated (Carter et al, 2010;Durand et al, 2012;Josefsson et al, 2012;Sebastian et al, 2017;Zaikos et al, 2018).…”