Deciphering HIV-1 Resistance Pathways against Capsid Inhibitors in vitro and in Humanized Mice

About This Grant

PROJECT SUMMARY The HIV-1 capsid, a cone-shaped protein shell, is a promising target for antiviral interventions, with lenacapavir (LEN), a potent capsid inhibitor, demonstrating efficacy in treatment and prevention. However, resistance to LEN has been reported in both in vitro and clinical contexts. Our preliminary studies have also identified LEN-resistant mutations not previously observed. As the use of capsid inhibitors is expected to expand in the future, a deeper understanding of drug resistance—especially its evolutionary trajectories and impact on viral fitness and transmissibility—is crucial, with broad clinical implications. In this grant, we will investigate HIV-1 resistance to LEN, exploring its potential and consequences using in vitro and in vivo models. In Aim 1, we will elucidate how HIV-1 acquires increased resistance to LEN through rationally designed, accelerated in vitro evolution approaches. We will use large-scale mutant libraries combined with multiplex selection and viral adaptation to comprehensively map drug resistance pathways. These LEN- resistant variants will then be assessed in a humanized mouse model of HIV-1 LEN treatment. LEN is under investigation for pre-exposure prophylaxis; however, the transmissibility of LEN-resistant HIV-1 variants remains unclear and may impact future prevention efforts. To address this, we will evaluate the transmission efficiency of LEN-resistant variants in a humanized mouse model of mucosal transmission. CA mutations conferring LEN resistance can affect multiple CA-dependent functions, potentially influencing viral transmissibility. Correlates of transmission by LEN-resistant variants will be determined using both high- throughput phenotypic assays and in vivo experiments.