Beta globin gene inhibition by antisense RNA transcripts

Sickle cell disease is caused by a mutation in the β globin gene leading to hemoglobin S (Hb S) production. Several approaches have been explored to prevent Hb S polymerization in red blood cells and the symptoms associated with this disorder. To this end we tested a mammalian expression vector carrying a human β globin antisense cDNA (pZeoβAS) fragment in a mouse erythroleukemia cell line expressing the human γ and β globin genes. We observed a relative reduction in β globin mRNA levels compared with γ mRNA levels in the presence of pZeoβAS. Moreover, analysis at the protein level showed an average 76% decrease in β chains and a 517% increase in γ chain biosynthesis. The inhibitory effect of the antisense vector on globin expression was maintained long term in culture. The expression vector pZeoβAS was also transfected into primary erythroid progenitors to test its effects on globin genes undergoing normal developmental switching during differentiation. We observed a relative reduction of β globin mRNA levels compared with γ mRNA levels. These results support a novel role for antisense cDNA expression vectors as an alternative gene therapy strategy to inhibit β(s) gene expression in sickle cell disease.