Implementing novel CRISPR screening models to inform HIV cure strategies by characterizing primary human CD4 T cell resistance to CD8 cytotoxicity

About This Grant

Project Abstract: Significant advances in antiretroviral therapy (ART) has enabled functional suppression of HIV, allowing individual individuals on ART to live relatively normal lives. However, viral rebound from a persistent reservoir of provirus-harboring cells following ART cessation demands a lifelong reliance on ART. ART-free control of this persistent reservoir therefore represents the current focus of HIV cure strategies. Recent work from our group and others has identified HIV-infected CD4 T cells that exhibit cell-intrinsic resistance to CD8 cytotoxicity, despite antigen expression and recognition. While identification of resistance factors previously annotated in cancer (such as overexpression of the granzyme inhibitor SERPINB9 and the anti-apoptotic protein BCL-2) has provided some insight concerning underlying mechanisms, the factors leading to this resistance phenotype remain largely unknown. To address this, we have developed a novel genome-wide screening platform that allows identification of genes involved in primary human CD4 T cell resistance and susceptibility to CD8 T cell cytotoxicity. In this proposal, we aim to maximize the potential of this newly developed CD4 resistance screening model (CRSM). Additional screens in different contexts will be conducted to further enrich the dataset. We will also employ a methodical pipeline for hit validation and therapeutic characterization. This pipeline will begin with promising hits identified in the initial screen, including the lipid metabolism-associated PPAR family proteins. This proposal will produce a robust functional genomic dataset thoroughly characterizing the mechanisms underlying CD4 resistance to CD8 killing. With these datasets, we envision the nomination of a range of promising targets for small-molecule sensitization of HIV-infected CD4s to CD8 killing.