KLF1 Knockdown Differentially Regulates γ-Globin Expression: Inhibition in K562 Cells but Reactivation in β-Thalassemia Major Erythrocytes with Erythropoiesis Disruption.

Backgound: Induction of fetal hemoglobin (HbF; α2γ2) production can alleviate the clinical severity of sickle cell disease (SCD) and β-thalassemia. KLF1 SNPs (e.g. rs2072597) correlate with elevated fetal hemoglobin levels in HPFH patients. Some studies suggest that KLF1 may indirectly suppress γ-globin expression by regulating the KLF1-dependent transcriptional repressor BCL11A or directly activate γ-globin. This study aims to investigate the effect of KLF1 on the γ-globin gene.

Material/methods: KLF1 was downregulated in K562 cells via RNAi, with optimized shRNA delivered by lentivirus. Additionally, an in vitro erythropoiesis model using β-thalassemia major-derived mononuclear cells (MNCs) assessed γ-globin expression. γ-globin levels were quantified by RT-qPCR and Western blot (K562) or RT-qPCR alone (erythroblasts).

Results: Knockdown of KLF1 in K562 cells significantly suppressed γ-globin expression and elevated the γ/α globin mRNA ratio in human erythrocytes, concurrent with disrupted erythroid maturation. KLF2 expression was upregulated under KLF1-deficient conditions.

Conclusions: KLF1 exhibits dual, context-dependent regulation of globin genes, acting as both activator and repressor. These findings suggest that pharmacological targeting of KLF1 may not be an optimal therapeutic strategy for β-hemoglobinopathies.