mi-RNA-mRNA Alterations in Sorted T-Cells of Acquired Aplastic Anemia: Validating the Observations of a Pilot Study

An altered T-cell repertoire with aberrant immune activation is central to the pathogenesis of acquired aplastic anemia (aAA), and miRNAs are known to orchestrate T-cell activation; their relationship is, however, incompletely explored in aAA. The study aimed to validate specific miRNA-mRNA pairs involved in aberrant T-cell activation, differentiation, and cytokine levels in aAA.

This was a prospective case-control study of 30 newly diagnosed patients with aAA and 10 healthy controls. The alterations in the expression of seven miRNAs were evaluated in the sorted T-cells isolated from the PB-MNCs. qRT-PCR was used to evaluate the miRNA expression, and fold change was calculated by the 2^ΔΔCt method. Target genes of the deregulated miRNAs were assessed by qRT-PCR. Cytokine profiling was carried out by cytokine bead array and qRT-PCR.

All seven miRNAs were differentially expressed in aAA, miR-155 (FC: 3.71) and miR-146b (fold change (FC): 5.86) were upregulated, while miR-126 (FC: 0.305), miR-181c (FC: 0.343), miR-16 (FC: 0.351), miR-326 (FC: 0.219), and miR-17 (FC: 0.38) were downregulated. These alterations correlated with disease severity. Target analysis showed increased expression of transcription factors promoting Th1/Th17 polarization and signaling molecules (PIK3R2, SOCS-1), with reduced expression of FOXP3, IRAK-1, TRAF-6, STAT-1, IFNGR, ETS-1, and PTEN. The miRNA-mRNA alterations in enriched T-cells mirrored those in PB-MNCs except for miR-17. Plasma levels of IL-2, IL-4, IL-6, and IL-10 (p = 0.069) were significantly elevated in aAA.

This study confirms the differential expression of miRNAs in aAA and their possible role in maintaining the aberrant T-cell repertoire in aAA. In vitro studies utilizing miRNA knockdown/miR-mimics may uncover newer therapeutic targets in aAA.