HIV-Infection Dysregulates MicroRNA Expression by Human Macrophages
Luers, Aimee Joanne
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Over 33 million people are infected with the Human Immunodeficiency Virus (HIV) worldwide. As the first cells infected during the pathogenesis of HIV, macrophages release virus and inflammatory factors over long periods of time. The role of macrophages in the pathogenesis of and response to HIV, particularly the regulation of their protein expression during infection, is still being examined. Macrophages use MicroRNAs (miRNAs), non-coding RNA molecules, to control protein expression. One report indicated that macrophages do not express Dicer, an important protein of the miRNA machinery. We used Western blot analyses to demonstrate the presence of key machinery proteins, Argonaut2 (Ago2), Dicer, DiGeorge Critical Region 8 (DGCR8), Drosha, Exportin5, and TAR-RNA Binding Protein (TRBP), in human primary monocyte derived macrophages (macrophages), and found a high degree of variability among the donors tested. Additionally, we used miRNA microarray to identify 119 miRNAs expressed by macrophages and validated hsa-let-7a, miR-16, -23a, 30b, -103, -146a, -212, and -378 expression by quantitative RT-PCR. We found large variability among our donors in expression of some miRNAs tested. These findings are the first demonstration of the machinery proteins and the miRNA expression profile in human primary macrophages. The variability in both machinery proteins and miRNAs will inform our understanding of how macrophage response to infection and/or disease pathogenesis may differ among individuals.;The contribution of macrophage miRNA expression to the pathogenesis of HIV is not well understood. Identification of the macrophage miRNA expression profile led us to hypothesize that it may be altered during HIV infection. Therefore, we used miRNA microarray of infected and uninfected macrophages and identified 13 miRNAs exhibiting dysregulated expression during HIV infection. We examined these expression differences using the OM10.1/HL-60 model system and quantitative RT-PCR, and found statistically significant differences in the expression of miR-99b, -125a-5p, and -146a in the presence of HIV. Using an antagomiR to miR-99b and a mimic to miR-146a, we determined that these miRNAs support viral replication through an undefined mechanism. These are among the first demonstrations of the direct impact of miRNA expression on HIV infection of macrophages.
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