Genomic discovery and functional validation of MRP1 as a novel fetal hemoglobin modulator and potential therapeutic target in sickle cell disease

ABSTRACT Sickle cell disease (SCD) remains a major health burden with limited treatment options. Despite promising gene-editing clinical trials, there is an unmet need for cost-effective therapies. As induction of fetal hemoglobin (HbF) is an established therapeutic strategy for SCD, we conducted a genome-wide association study of circulating HbF levels in ~11,000 participants to identify further HbF modulators. We identified associations in 11 genomic regions, including eight novel loci such as ABCC1 (encoding multidrug resistance-associated protein 1, MRP1). Using gene-editing and pharmacological approaches, we showed that inhibition of MRP1 increases HbF, intracellular glutathione levels, and reduces sickling in erythroid cells from SCD patients. Overall, our findings identify several novel genetically-validated potential therapeutic targets for SCD, including promising proof-of-principle results from small molecule inhibition of MRP1.