There are an estimated 37 million people worldwide infected with HIV, with about 1 million infected in the U.S.  Even with the existence of highly active antiretroviral therapy (HAART) regimens, the associated toxicities and the evolution of multi-drug resistant HIV create a need for new therapeutic breakthroughs.  Gene-editing technologies, particularly the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated Cas9 system, are being explored for their potential to provide new, unique treatments for HIV.  Recent advances in CRISPR/Cas9 therapy have allowed for targeting the HIV genome to completely excise the integrated proviral sequence.  Due to the rapid mutation of HIV sequence, even within clinically suppressed individuals, targeting the virus is non-trivial. 

Researchers in Drexel’s Department of Microbiology & Immunology and Institute for Molecular Medicine & Infectious Disease have addressed a major challenge of CRISPR/Cas9-mediated HIV-1 proviral genome eradication by developing an algorithm that utilizes the inherent promiscuity of CRISPR/Cas9 targeting to ensure a broad spectrum targeting ability.  Software has been developed that analyzed next generation sequencing data from HIV-infected patient samples to determine a set of guide RNAs (gRNAs) that target the large number of HIV genetic variants within single individuals and an even greater number of HIV variants across large numbers of HIV-1-infected patients.  Furthermore, gRNAs are selected such that the off-target effect is minimal, even when considering all SNPs within the human genome known to date. The gRNAs are designed to specifically target the HIV-1 LTR region and can be used with CRISPR/Cas-9 in compositions to develop not only individualized HIV-1 treatments but broad spectrum therapies designed to work across larger numbers of patients.