Structure-guided drug design identifies a BRD4-selective small molecule that suppresses HIV
Qingli Niu, Zhiqing Liu, Edrous Alamer, Xiuzhen Fan, Haiying Chen, Janice Endsley, Benjamin B. Gelman, Bing Tian, Jerome H. Kim, Nelson L. Michael, Merlin L. Robb, Jintanat Ananworanich, Jia Zhou, Haitao Hu
Qingli Niu, Zhiqing Liu, Edrous Alamer, Xiuzhen Fan, Haiying Chen, Janice Endsley, Benjamin B. Gelman, Bing Tian, Jerome H. Kim, Nelson L. Michael, Merlin L. Robb, Jintanat Ananworanich, Jia Zhou, Haitao Hu
View: Text | PDF
Research Article AIDS/HIV

Structure-guided drug design identifies a BRD4-selective small molecule that suppresses HIV

Abstract

HIV integrates its provirus into the host genome and establishes latent infection. Antiretroviral therapy (ART) can control HIV viremia, but cannot eradicate or cure the virus. Approaches targeting host epigenetic machinery to repress HIV, leading to an aviremic state free of ART, are needed. Bromodomain and extraterminal (BET) family protein BRD4 is an epigenetic reader involved in HIV transcriptional regulation. Using structure-guided drug design, we identified a small molecule (ZL0580) that induced epigenetic suppression of HIV via BRD4. We showed that ZL0580 induced HIV suppression in multiple in vitro and ex vivo cell models. Combination treatment of cells of aviremic HIV-infected individuals with ART and ZL0580 revealed that ZL0580 accelerated HIV suppression during ART and delayed viral rebound after ART cessation. Mechanistically different from the BET/BRD4 pan-inhibitor JQ1, which nonselectively binds to BD1 and BD2 domains of all BET proteins, ZL0580 selectively bound to BD1 domain of BRD4. We further demonstrate that ZL0580 induced HIV suppression by inhibiting Tat transactivation and transcription elongation as well as by inducing repressive chromatin structure at the HIV promoter. Our findings establish a proof of concept for modulation of BRD4 to epigenetically suppress HIV and provide a promising chemical scaffold for the development of probes and/or therapeutic agents for HIV epigenetic silencing.

Authors

Qingli Niu, Zhiqing Liu, Edrous Alamer, Xiuzhen Fan, Haiying Chen, Janice Endsley, Benjamin B. Gelman, Bing Tian, Jerome H. Kim, Nelson L. Michael, Merlin L. Robb, Jintanat Ananworanich, Jia Zhou, Haitao Hu

×

Figure 5

ZL0580 selectively binds to BRD4 (BD1), and BRD4 is functionally required for ZL0580-induced HIV suppression.

Options: View larger image (or click on image) Download as PowerPoint
ZL0580 selectively binds to BRD4 (BD1), and BRD4 is functionally require...
(A) In vitro binding of ZL0580 or JQ1 to BD1 and BD2 of BET proteins measured by TR-FRET (IC50, nM). Error bars represent SD of assay replicates. (B) CRISPR/Cas9 KO of BRD4 and BRD2 in J-Lat cells. (C and D) BRD4 KO abrogates ZL5080-induced HIV suppression. VC, BRD4-KO, or BRD2-KO cells were treated as indicated. Representative FACS plots for GFP expression (C) and cumulative data comparing GFP+ percentage in VC and KO J-Lat cells from 3 independent experiments (mean ± SD) (D) are shown. (E) Expression of Gag and 3′ LTR RNAs in PMA-activated, VC, or BRD4-KO cells after treatment (24 hours). (F) Expression of 3′ LTR RNA in unstimulated, VC, or BRD4-KO J-Lat cells after different treatments (on day 7). (G) Exogenous BRD4 expression in BRD4-KO J-Lat. KO cells were nucleofected with pcDNA-FLAG-BRD4 plasmid (+) or not treated (–). BRD4 expression was measured by Western blot using anti-BRD4 and anti-FLAG antibody (day 4 after nucleofection). VC was included as a control. (H and I) Effect of BRD4 overexpression on ZL0580-induced HIV suppression. BRD4-KO cells without (top) or with BRD4 overexpression (bottom) were treated as indicated. Representative FACS plots for GFP expression (H) and cumulative data comparing GFP+ percentage of J-Lat cells among different treatments (I) are shown. In this figure, error bars show SD of experimental replicates (D and I) and of PCR duplicate (E and F). Experiments were repeated at least 3 times. **P < 0.005, paired Student’s t test (D–F, I).