Title: Role of MicroRNA in Hydroxyurea mediated HbF induction in Sickle cell anaemia patients
Abstract: Abstract Background: Hydroxyurea (HU) is found to be beneficial in Sickle cell Anaemia (SCA) patients, due to its ability to increase foetal haemoglobin (HbF), however, patients show a variable response. Differences in HbF levels are attributed to many factors; but, the role of miRNA in HbF regulation is sparsely investigated. Materials and Methods: In this study, we evaluated the effect of miRNA expression on HbF induction in relation to hydroxyurea therapy in 30 normal controls, 30 SCA patients at baseline, 20 patients after 3 and 6 months of hydroxyurea (HU) therapy. HbF levels were measured by HPLC. Total RNA and miRNA were extracted from CD71 + erythroid cells and the expression was determined using Taqman probes. Results: The mean HbF level increased 7.54 ±2.44 fold, after 3 months of HU therapy. After the HU therapy 8 miRNAs were significantly up-regulated while 2 were down-regulated. The increase in miR-210, miR16-1, and miR-29a expression and decrease in miR-96 expression were strongly associated with the HU mediated HbF induction. Post HU therapy, decreased miR-96 expression was observed; which might be due to interference of miR-96 binding to g-globin mRNA by HU, facilitating HbF expression. The miR-210 expression was enhanced in association with erythroid differentiation and induction to HbF production. Conclusions: The study suggests the role of miR-210, miR16-1, miR-29a, and miR-96 in g-globin gene regulation leading to HbF induction. Identification of the relevant protein targets might be useful for understanding the HU mediated HbF induction.