CRISPR-Cas9 high-throughput screening to study drug resistance in Leishmania infantum

作者：Marine Queffeulou, Philippe Leprohon, Christopher Fernandez‐Prada, Marc Ouellette, Ana María Mejía‐Jaramillo · 发表于：mBio · 年份：2024 · DOI：10.1128/mbio.00477-24 · 被引用次数：25 · 研究领域：Research on Leishmaniasis Studies、Trypanosoma species research and implications、CRISPR and Genetic Engineering

ABSTRACT Parasites of the genus Leishmania pose a global health threat with limited treatment options. New drugs are urgently needed, and genomic screens have the potential to accelerate target discovery, mode of action, and resistance mechanisms against these new drugs. We describe here our effort in developing a genome-wide CRISPR-Cas9 screen in Leishmania , an organism lacking a functional nonhomologous end joining system that must rely on microhomology-mediated end joining, single-strand annealing, or homologous recombination for repairing Cas9-induced double-stranded DNA breaks. A new vector for cloning and expressing single guide RNAs (sgRNAs) was designed and proven to be effective in a small pilot project while enriching specific sgRNAs during drug selection. We then developed a whole-genome library of 49,754 sgRNAs, targeting all the genes of Leishmania infantum . This library was transfected in L. infantum expressing Cas9, and these cells were selected for resistance to two antileishmanials, miltefosine and amphotericin B. The sgRNAs the most enriched in the miltefosine screen targeted the miltefosine transporter gene, but sgRNAs targeting genes coding for a RING-variant protein and a transmembrane protein were also enriched. The sgRNAs the most enriched by amphotericin B targeted the sterol 24 C methyltransferase genes and a hypothetical gene. Through gene disruption experiments, we proved that loss of function of these genes was associated with resistance. This st...