Iron depletion by iron chelators or ferroportin inhibits HIV-1 through the induction of HIF1α, p21 and IKBα and the inhibition of CDK9 and CDK2

Abstract

Background Intracellular iron and oxygen levels regulate HIV-1 replication by affecting several steps in the HIV-1 life cycle including transcription [1]. Low oxygen levels and reduced cellular iron are inhibitory as CDK9/cyclin T1 and CDK2/ cyclin E activities are reduced and HIV-1 transcription is inhibited. The alpha subunit of hypoxia-induced factor 1 (HIF1a) is stabilized under hypoxia and in the conditions of low cellular iron. Iron depletion by iron chelators or through the expression of ferroportin, an iron export protein, inhibits CDK2 and CDK9 activities and blocks HIV-1 transcription [1]. As neither CDK2 nor CDK9 requires iron for their enzymatic activity, an apparent upstream regulation is involved. Also, induction of heme oxygenase-1 (HO-1) by hemin was shown to inhibit HIV-1 [1] although the mechanism of the inhibition was not clarified. Here we analyzed the effect of iron chelators on HIV-1 transcription and replication and also analyzed the effect of heme, a condition present in sickle cell disease that may protect against HIV-1 infection [2].