Transcriptional Modification and Potential Intracellular Signaling Mechanisms in Human Macrophages Primed by Interferon-γ

Abstract

To explore the transcriptional gene expression profile up-regulated in human macrophages stimulated by interferon-γ (IFN-γ) and the underlying intracellular signaling mechanisms. RNA-seq was used to sequence and compare the differential gene expression profiles of human macrophage cell line U937 before and after IFN-γ stimulation, and the significantly up-regulated genes were screened out, which were verified by fluorescence-based real-time quantitative polymerase chain reaction (qPCR) in U937 and THP1 cell lines, respectively. JAK/STAT, MAPK/ERK and PI3K/AKT pathway inhibitors were added to simultaneously to the cultured U937 cells upon IFN-γ priming to detect their effects on the expressions of the up-regulated genes to explore the key regulatory mechanisms. RNA-seq and qPCR results showed that, the well-recognized chemokines CXCL9, CXCL10 and CXCL11, the APOL family including APOL1, APOL2, APOL3, APOL4, APOL6 and GBP family GBP1, GBP2, GBP3, GBP4 and GBP5 as well were significantly up-regulated in IFN-γ-stimulated U937 cells. JAK/STAT3 pathway inhibitor inhibited the upregulation of APOL1, APOL4, GBP1, GBP4 and GBP5 genes induced by IFN-γ, while MAPK/ERK pathway inhibitor inhibited the upregulation of CXCL10 gene. PI3K/AKT pathway inhibitor inhibited the upregulation of APOL1,APOL4, APOL6, GBP1 and GBP5 genes induced by IFN-γ, all three signal pathway inhibitors could inhibit the upregulation of CXCL9 gene, and none of them could inhibit the upregulation of APOL3 gene. Upon IFN-γ stimulation, some family molecules of APOL and GBP in macrophages are significantly up-regulated, and PI3K/AKT, JAK/STAT3 and MAPK/ERK pathways have positive regulation on their expressions, respectively.