Abstract
The ability of HIV-1 to evolve resistance to combined antiretroviral therapies (cARTs) has stimulated research into alternative means of controlling this infection. We assayed >60 modulators of RNA alternative splicing (AS) to identify new inhibitors of HIV-1 RNA processing-a segment of the viral lifecycle not targeted by current drugs-and discovered compound N-[4-chloro-3-(trifluoromethyl)phenyl]-7-nitro-2,1,3-benzoxadiazol-4-amine (5342191) as a potent inhibitor of both wild-type (Ba-L, NL4-3, LAI, IIIB, and N54) and drug-resistant strains of HIV-1 (IC50: ~700 nM) with no significant effect on cell viability at doses tested. 5342191 blocks expression of four essential HIV-1 structural and regulatory proteins (Gag, Env, Tat, and Rev) without affecting total protein synthesis of the cell. This response is associated with altered unspliced (US) and singly-spliced (SS) HIV-1 RNA accumulation (~60% reduction) and transport to the cytoplasm (loss of Rev) whereas parallel analysis of cellular RNAs revealed less than a 0.7% of host alternative splicing (AS) events (0.25-0.67% by ≥ 10-20%), gene expression (0.01-0.46% by ≥ 2-5 fold), and protein abundance (0.02-0.34% by ≥ 1.5-2 fold) being affected. Decreased expression of Tat, but not Gag/Env, upon 5342191 treatment was reversed by a proteasome inhibitor, suggesting that this compound alters the synthesis/degradation of this key viral factor. Consistent with an affect on HIV-1 RNA processing, 5342191 treatment of cells altered the abundance and phosphorylation of serine/arginine-rich splicing factor (SRSF) 1, 3, and 4. Despite the activation of several intracellular signaling pathways by 5342191 (Ras, MEK1/2-ERK1/2, and JNK1/2/3), inhibition of HIV-1 gene expression by this compound could be reversed by pre-treatment with either a G-protein α-subunit inhibitor or two different MEK1/2 inhibitors. These observations demonstrate enhanced sensitivity of HIV-1 gene expression to small changes in host RNA processing and highlights the potential of modulating host intracellular signaling as an alternative approach for controlling HIV-1 infection.
Highlights
IntroductionIn the absence of a vaccine against HIV-1, combined antiretroviral therapies (cARTs) are needed to control the spread and progression of the virus [2,3]
Over 36.9 million people are living with HIV/AIDS [1]
We assayed over 60 compounds for new inhibitors of HIV-1 RNA processing—an area of the virus lifecycle not targeted by current drugs and primarily under the control of the host cell—and identified compound 5342191 as a potent inhibitor of multiple wild-type and drug-resistant strains of HIV-1
Summary
In the absence of a vaccine against HIV-1, cARTs are needed to control the spread and progression of the virus [2,3]. These ARTs target HIV-1 envelope (Env) interactions with its co-receptor (CR) or fusion with the cell membrane, reverse transcriptase (RT), integrase (IN), and protease (PR) [3,4]. Inhibition of HIV-1 gene expression by CSs requires, in part, activation of mitogen-activated protein (MAP) kinase (MAPK)/extracellular signal-regulated kinase (ERK) kinase (MEK) 1/2-ERK1/2 by a mechanism that is independent of the toxic/arrhythmogenic properties of this family of drugs [28]. While MEK1/2-ERK1/2 signaling may play a supportive role during early stages
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
