Epigenetic heterogeneity in HIV-1 latency establishment

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• Human immunodeficiency virus type 1 (HIV-1) establishes a latent reservoir despite antiretroviral therapy, hindering AIDS cure.
• Understanding the mechanisms of HIV-1 latency establishment is crucial for developing strategies to reduce this latent reservoir.

Purpose of the Study:

• To molecularly characterize distinct HIV-1 populations during early infection.
• To elucidate the mechanisms and kinetics of latency establishment and maintenance.

Main Methods:

• Development of an original dual-color reporter virus to monitor Long Terminal Repeat (LTR) kinetics.
• Analysis of histone covalent modifications, specifically polycomb repressive complex 2 (PRC2)-mediated H3K27 trimethylation.

Main Results:

• Identified two distinct pathways for HIV-1 latency establishment: immediate silencing and slow inactivation from active infection.
• Demonstrated that PRC2-mediated H3K27 trimethylation plays a dominant role in viral transcription during early infection and contributes to LTR dormancy in the chronic phase.
• Observed significant differences in the sensitivity of these two populations to various stimuli.

Conclusions:

• HIV-1 latency establishment is heterogeneous, occurring through at least two distinct mechanisms.
• Histone modifications, particularly PRC2 activity, are critical regulators of HIV-1 transcriptional silencing and latency maintenance.
• These findings enhance the understanding of HIV-1 latency heterogeneity and may inform therapeutic strategies.