An activator of G protein-coupled receptor and MEK1/2-ERK1/2 signaling inhibits HIV-1 replication by altering viral RNA processing

PLoS Pathog. 2020 Feb 18;16(2):e1008307. doi: 10.1371/journal.ppat.1008307. eCollection 2020 Feb.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing / drug effects*
  • Alternative Splicing / physiology
  • Gene Expression / genetics
  • Gene Expression Regulation, Viral / genetics
  • HIV Infections
  • HIV Seropositivity
  • HIV-1 / physiology
  • HeLa Cells
  • Humans
  • MAP Kinase Kinase 1 / metabolism
  • MAP Kinase Kinase Kinase 2 / metabolism
  • MAP Kinase Signaling System / physiology
  • RNA Processing, Post-Transcriptional / physiology
  • RNA Splicing / genetics
  • RNA, Viral / genetics
  • Receptors, G-Protein-Coupled / metabolism
  • Signal Transduction / physiology
  • Small Molecule Libraries
  • Virus Replication / drug effects*
  • Virus Replication / physiology
  • tat Gene Products, Human Immunodeficiency Virus / genetics

Substances

  • RNA, Viral
  • Receptors, G-Protein-Coupled
  • Small Molecule Libraries
  • tat Gene Products, Human Immunodeficiency Virus
  • MAP Kinase Kinase Kinase 2
  • MAP Kinase Kinase 1