A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis

Abstract Background Although macrophages are now recognized as an essential part of the HIV latent reservoir, whether and how viral latency is established and reactivated in these cell types is poorly understood. To understand the fundamental mechanisms of viral latency in macrophages, there is an u...

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Main Authors: Javan K. Kisaka, Daniel Rauch, Malachi Griffith, George B. Kyei
Format: Article
Language:English
Published: BMC 2024-04-01
Series:Virology Journal
Subjects:
Online Access:https://doi.org/10.1186/s12985-024-02343-9
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author Javan K. Kisaka
Daniel Rauch
Malachi Griffith
George B. Kyei
author_facet Javan K. Kisaka
Daniel Rauch
Malachi Griffith
George B. Kyei
author_sort Javan K. Kisaka
collection DOAJ
description Abstract Background Although macrophages are now recognized as an essential part of the HIV latent reservoir, whether and how viral latency is established and reactivated in these cell types is poorly understood. To understand the fundamental mechanisms of viral latency in macrophages, there is an urgent need to develop latency models amenable to genetic manipulations and screening for appropriate latency-reversing agents (LRAs). Given that differentiated THP-1 cells resemble monocyte-derived macrophages in HIV replication mechanisms, we set out to establish a macrophage cell model for HIV latency using THP-1 cells. Methods We created single-cell clones of THP-1 cells infected with a single copy of the dual-labeled HIVGKO in which a codon switched eGFP (csGFP) is under the control of the HIV-1 5’ LTR promoter, and a monomeric Kusabira orange 2 (mKO2) under the control of cellular elongation factor one alpha promoter (EF1α). Latently infected cells are csGFP−, mKO2+, while cells with actively replicating HIV (or reactivated virus) are csGFP+,mKO2+. After sorting for latently infected cells, each of the THP-1 clones with unique integration sites for HIV was differentiated into macrophage-like cells with phorbol 12-myristate 13-acetate (PMA) and treated with established LRAs to stimulate HIV reactivation. Monocyte-derived macrophages (MDMs) harboring single copies of HIVGKO were used to confirm our findings. Results We obtained clones of THP-1 cells with latently infected HIV with unique integration sites. When the differentiated THP-1 or primary MDMs cells were treated with various LRAs, the bromodomain inhibitors JQ1 and I-BET151 were the most potent compounds. Knockdown of BRD4, the target of JQ1, resulted in increased reactivation, thus confirming the pharmacological effect. The DYRK1A inhibitor Harmine and lipopolysaccharide (LPS) also showed significant reactivation across all three MDM donors. Remarkably, LRAs like PMA/ionomycin, bryostatin-1, and histone deacetylase inhibitors known to potently reactivate latent HIV in CD4 + T cells showed little activity in macrophages. Conclusions Our results indicate that this model could be used to screen for appropriate LRAs for macrophages and show that HIV latency and reactivation mechanisms in macrophages may be distinct from those of CD4 + T cells.
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spelling doaj.art-8c94df1c588449a6bb188a9517454e3e2024-04-07T11:08:23ZengBMCVirology Journal1743-422X2024-04-0121111310.1186/s12985-024-02343-9A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axisJavan K. Kisaka0Daniel Rauch1Malachi Griffith2George B. Kyei3Department of Medicine, Washington University School of Medicine in St. LouisDepartment of Medicine, Washington University School of Medicine in St. LouisDepartment of Medicine, Washington University School of Medicine in St. LouisDepartment of Medicine, Washington University School of Medicine in St. LouisAbstract Background Although macrophages are now recognized as an essential part of the HIV latent reservoir, whether and how viral latency is established and reactivated in these cell types is poorly understood. To understand the fundamental mechanisms of viral latency in macrophages, there is an urgent need to develop latency models amenable to genetic manipulations and screening for appropriate latency-reversing agents (LRAs). Given that differentiated THP-1 cells resemble monocyte-derived macrophages in HIV replication mechanisms, we set out to establish a macrophage cell model for HIV latency using THP-1 cells. Methods We created single-cell clones of THP-1 cells infected with a single copy of the dual-labeled HIVGKO in which a codon switched eGFP (csGFP) is under the control of the HIV-1 5’ LTR promoter, and a monomeric Kusabira orange 2 (mKO2) under the control of cellular elongation factor one alpha promoter (EF1α). Latently infected cells are csGFP−, mKO2+, while cells with actively replicating HIV (or reactivated virus) are csGFP+,mKO2+. After sorting for latently infected cells, each of the THP-1 clones with unique integration sites for HIV was differentiated into macrophage-like cells with phorbol 12-myristate 13-acetate (PMA) and treated with established LRAs to stimulate HIV reactivation. Monocyte-derived macrophages (MDMs) harboring single copies of HIVGKO were used to confirm our findings. Results We obtained clones of THP-1 cells with latently infected HIV with unique integration sites. When the differentiated THP-1 or primary MDMs cells were treated with various LRAs, the bromodomain inhibitors JQ1 and I-BET151 were the most potent compounds. Knockdown of BRD4, the target of JQ1, resulted in increased reactivation, thus confirming the pharmacological effect. The DYRK1A inhibitor Harmine and lipopolysaccharide (LPS) also showed significant reactivation across all three MDM donors. Remarkably, LRAs like PMA/ionomycin, bryostatin-1, and histone deacetylase inhibitors known to potently reactivate latent HIV in CD4 + T cells showed little activity in macrophages. Conclusions Our results indicate that this model could be used to screen for appropriate LRAs for macrophages and show that HIV latency and reactivation mechanisms in macrophages may be distinct from those of CD4 + T cells.https://doi.org/10.1186/s12985-024-02343-9HIVMacrophagesLatencyLatency-reversing agentsTHP-1Cell line model
spellingShingle Javan K. Kisaka
Daniel Rauch
Malachi Griffith
George B. Kyei
A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
Virology Journal
HIV
Macrophages
Latency
Latency-reversing agents
THP-1
Cell line model
title A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
title_full A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
title_fullStr A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
title_full_unstemmed A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
title_short A macrophage-cell model of HIV latency reveals the unusual importance of the bromodomain axis
title_sort macrophage cell model of hiv latency reveals the unusual importance of the bromodomain axis
topic HIV
Macrophages
Latency
Latency-reversing agents
THP-1
Cell line model
url https://doi.org/10.1186/s12985-024-02343-9
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