CSF-induced and HIV-1–mediated Distinct Regulation of Hck and C/EBPβ Represent a Heterogeneous Susceptibility of Monocyte-derived Macrophages to M-tropic HIV-1 Infection

Granulocyte/macrophage colony-stimulating factor (GM-CSF)-induced monocyte-derived macrophages (GM-MPhi) are permissive to M-tropic HIV-1 entry, but inhibit viral replication at posttranscriptional and translational levels, whereas M-CSF-induced macrophages (M-MPhi) produce a large amount of HIV-1. M-MPhi express a high level of Hck and a large isoform of C/EBPbeta, and HIV-1 infection increases the expression of Hck but not of C/EBPbeta. GM-MPhi express a high level of C/EBPbeta and a low level of Hck, and HIV-1 infection drastically increases the expression of a short isoform of C/EBPbeta but decreases that of Hck. Treatment of M-MPhi with antisense oligonucleotide for Hck (AS-Hck) not only suppresses the expression of Hck, but also stimulates the induction of the short isoform of C/EBPbeta and inhibits the viral replication. Treatment of GM-MPhi with a moderate amount of AS-C/EBPbeta not only inhibits the expression of the small isoform of C/EBPbeta preferentially, but also stimulates the induction of Hck and stimulates the virus production at a high rate. These results suggest that CSF-induced and HIV-1-mediated distinct regulation of Hck and small isoform of C/EBPbeta represent the heterogeneous susceptibility of tissue MPhi to HIV-1 infection, and the regulation of Hck and C/EBPbeta are closely related and these two molecules affect one another.