CRISPR-Cas based strategies against HIV-1

Current combined antiretroviral therapy (cART) can effectively reduce the viral load in patients to undetectable levels. However, the virus can quickly rebound from this reservoir if the therapy is interrupted. The reason is that cART does not target the viral reservoir in long-lived resting T cells and other cell types. Therefore, one of the potential approaches towards a real cure is to inactivate/eradicate the HIV provirus integrated into human genome of the reservoir cells. In this thesis, the new genome engineering system CRISPR-Cas has been studied to realize this goal. First, efficient inhibition of HIV replication was observed when CRISPR-Cas9 was used to target the HIV provirus. But surprisingly rapid, NHEJ-facilitated HIV escape from CRISPR-Cas9 inhibition was also observed (chapter 2). We subsequently tested several strategies to prevent HIV escape (chapter 3), but success was achieved only by a combinatorial attack with two gRNAs at conserved domains in the HIV-1 genome (chapter 4). Second, we investigated whether dual inhibition of HIV DNA and RNA (CRISPR-Cas9 and RNAi) at overlapping or non-overlapping sites in the HIV genome can improve the antiviral efficiency (chapter 5). Finally, we reviewed CRISPR-Cas9 mediated strategies against HIV-1 (chapter 6).