Decoding HbF reactivation by hydroxyurea in hemoglobinopathy patients through microRNA signatures

Hydroxyurea promotes HbF elevation in b-thalassemia and sickle cell anemia patients however, its mechanism is not completely elucidated. Previous studies have associated microRNAs with the regulation of HBG2, prompting this study to investigate specific microRNAs linked to HbF regulation in patients treated with hydroxyurea. 150 patients were recruited in the study. miRNA microarray panel of 754 miRNAs was used, and a further customised microarray card was designed. In silico tools predicted target genes of miRNAs and in vitro transfection functionally validated miRNAs in erythroblast cells from patients and K562 cells. Global microarray revealed 59 differentially expressed miRNAs, with 42 upregulated and 17 downregulated significantly following 3/6 months of hydroxyurea treatment (p < 0.001). Further, the customised miRNA panel of these 59 miRNAs confirmed the results. Among 59 miRNAs, 12 upregulated and 3 downregulated miRNAs correlated with HBG2 expression and HbF levels. In silico predictions and in vitro cells study identified miR-150, miR-155, miR-374, miR-486-3p (BCL11A, MYB); miR-190, miR-26a, miR-30b, miR-362, miR-411 (BCL11A); miR-192, miR-454 (MYB); miR-326 (KLF1); miR-150 (GATA1) and miR-15a, miR-484, miR-105 commonly share BCL11A, MYB, KLF1 and GATA1. Our study uncovers how microRNAs influence fetal hemoglobin induction in patients with hydroxyurea treatment, thus offering insights for developing treatment strategies and alleviating clinical severity.