Cell-to-cell transmission and intrinsic mechanisms that influence human immunodeficiency virus infection
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Abstract
Early in the course of human immunodeficiency virus (HIV) infection a population of latently infected cells is established which persists despite long-term anti-retroviral treatment. This latent reservoir of HIV-infected cells, which reflects mechanisms of transcriptional repression, is the major barrier to cure. Efforts to target the latent reservoir have been inefficient, indicating a need for a more complete understanding of how HIV transcription is regulated.
The molecular networks involved in the regulation of HIV transcription remain incompletely defined. I hypothesized that utilization of a high throughput enhanced yeast one-hybrid assay would reveal novel host transcription factor-long terminal repeat (LTR) interactions and transcriptional networks that regulate HIV. The screen identified 42 human transcription factors and 85 total protein-DNA interactions with HIV LTRs. I investigated a subset of these factors for transcriptional activity in cell-based models of infection. Krüppel-like factors 2 and 3 (KLF2 and KLF3) are repressors of HIV-1 and HIV-2 transcription whereas PLAG1-like zinc finger 1 (PLAGL1) is an activator of HIV-2 transcription. These factors regulate HIV expression through direct protein-DNA interactions and correlate with epigenetic modifications of the HIV LTR.
Multiple signals converging from the cellular environment and cell-cell interactions converge at the HIV LTR to determine HIV replication and transcription. Previous work in our lab has shown that strong signaling through the T cell receptor (TCR) was required to support HIV expression and the establishment of an inducible latent infection, whereas weak TCR signaling was insufficient for these outcomes. I hypothesized that dendritic cells-CD4+ T cell interactions provide signals that compensate for weak TCR signaling, supporting HIV-1 expression and generation of inducible latent infection. I used CD4+ T cells that express chimeric antigen receptors in a dendritic cell coculture model to deliver differential signals to CD4+ T cells during cell-to-cell transmission of HIV. I found that signals from dendritic cells compensate for weak TCR signaling, facilitating cell activation, HIV expression and establishment of an inducible infection.
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Attribution-NonCommercial-NoDerivatives 4.0 International