<i>TSC1</i> and <i>DEPDC5</i> regulate HIV-1 latency through the mTOR signaling pathway

The latent reservoir of HIV-1 presents a major barrier to viral eradication. The mechanism of the establishment and maintenance of the latent viral reservoir is not yet fully understood, which hinders the development of effective curative strategies. In this study, we identified two inhibitory genes, <i>TSC1</i> and <i>DEPDC5</i>, that maintained HIV-1 latency by suppressing the mTORC1 pathway. We first adapted a genome-wide CRISPR screening approach to identify host factors required for HIV latency in a T-cell-based latency model and discovered two inhibitory genes, <i>TSC1</i> and <i>DEPDC5</i>, which are potentially involved in HIV-1 latency. Knockout of either <i>TSC1</i> or <i>DEPDC5</i> led to enhanced HIV-1 reactivation in both a T-cell line (C11) and a monocyte cell line (U1), and this enhancement could be antagonized by the mTORC1 inhibitor rapamycin. Further evaluation of the mechanism revealed that <i>TSC1</i> suppresses AKT-mTORC1-S6 via downregulation of Rheb, whereas <i>DEPDC5</i> inhibits AKT-mTORC1-S6 through RagA. Overall, both <i>TSC1</i> and <i>DEPDC5</i> negatively regulate the AKT-mTORC1 pathway, and thus their agonists could be used in the development of new therapeutic approaches for activating HIV-1 latency.