Real-time quantitative PCR analysis of microRNAs in human PBMC samples

A significant percentage of HIV-infected individuals experience a sharp decline in CD4+ T cell counts and progress to AIDS quickly after primary infection. Identification of biomarkers distinguishing rapid progressors (RPs) versus chronic progressors (CPs) is critical for early clinical intervention and could provide novel strategies to facilitate vaccine design and immune therapy. mRNA and miRNA expression profiles in the peripheral blood mononuclear cells (PBMCs) of RPs and CPs were investigated at 111±22 days (Mean±SD) of HIV infection. The association of mRNA and miRNA expression with disease progression was examined by receiver operating characteristic analysis and Kaplan-Meier survival analysis. Pathway enrichment analysis showed that genes with deregulated expression in RPs are primarily involved in apoptosis pathways. Furthermore, we found that 5 miRNAs (miR-31, -200c, -526a, -99a and -503) in RPs were significantly decreased compared to those in CPs (P<0.05). The decreased expression of these miRNAs was associated with rapid disease progression of HIV infection with a 94% predictive value as measured by the area under the curve. The upregulated predicted targets from the 5 signature miRNAs and all upregulated genes identified from mRNA microarray converged to the apoptosis pathway. Moreover, overexpression of miR-31 in primary human T cells promoted their survival. Our results have identified a distinct transcriptomic signature in PBMCs of RPs and provided novel insights to the pathogenesis of HIV infection. The initial 347 miRNA array was performed in 11 RPs, 6 CPs and 4 corresponding matched normal controls (training group); and only the miRNAs differentially expressed between RPs and CPs (P<0.05) in training group were detected in a subsequent validation group (19 RPs versus 10 CPs). miRNAs differentially expressed in 17 early HIV infected patients (including 11 RPs and 6 CPs) and 4 healthy controls in training cohort were firstly identified. Then, miRNAs differed RPs from CPs were compared in both training and validation cohort.