The technology maps insert-specific expression across thousands of integrated HIV proviruses in the whole human genome.
The technology can be used to identify the best (mix of) latency-reversing agents that can reactivate all latent HIV viruses which escape from antiretroviral therapies, making them susceptible to destruction.
After integration in the genome of an infected cell, a fraction of the HIV proviruses becomes latent. These proviruses are invisible for the immune system and are not targetable by antiretroviral therapy. Therefore, they remain a threat for the patient, because, at a later time, they will awaken and restart the infection cycle. One appealing strategy to tackle this problem is using latency-reversing agents (LRAs). LRAs can reactivate latent HIV proviruses so that they can be targeted and cleared. Although promising in preclinical studies, current LRAs are only minimally effective in patient cells.
Scientists from the Filion Group established a novel high-throughput technology, called B-HIVE, to study HIV latency and to characterize the mechanism of action of LRAs. This tool allows the identification of new and effective HIV reactivation therapies. The strategy involves the barcoding of a large population of recombinant viruses. With the barcodes, each individual virus can be linked to its insertion site in the genome and its expression levels measured after infection of a heterogeneous cell population. This allows to map HIV insertion patterns in the genome and to identify which latent proviruses are reactivated by a given reactivation therapy. Moreover, using this strategy, they unveiled that different classes of LRAs reactivate provirus inserted at different locations in the human genome. For example, proviruses that better responded to the histone deacetylase inhibitor vorinostat, were more frequently in the proximity of enhancers than the proviruses that better responded to the mitogen phytohemagglutinin. These findings demonstrate the value of B-HIVE to identify the best (mix of) latency-reversing agents that can reactivate all the latent viruses and make them susceptible to destruction.
B-HIVE is thus a unique technology to study HIV latency and to characterize LRAs. The Filion Group is interested in a collaboration to apply B-HIVE in the search for the best (mix of) drugs that can reactivate all the latent viruses.
• Highly useful tool to study mechanisms of HIV latency.
• In contrast to current models, B-HIVE identifies the subset of proviruses targeted by any given reactivation therapy. This is useful to optimize latency-reversing therapeutic strategies with current and newly identified LRAs.
• Suited to screen for novel LRAs and their mechanism of action, i.e. which latent proviruses are reactivated.
• Extendable to other latent proviral infectious diseases
Chen et al. Position effects influence HIV latency reversal. Nature Structural & Molecular Biology 2016, doi: 10.1038/nsmb.3328.