Regulation of T lymphocyte activation by microRNA-21

miR-21 is a negative modulator of T-cell activation

“…On the contrary, Wang and co-workers [30] obtained different results by miR-21 transfection into murine T-lymphoctes and Jurkat cells. However, it should be noted that in our experimental setting a 20-fold upregulation of miR-21 was obtained via lentiviral transduction in human primary T-lymphocytes, resembling the physiological upregulation of this miRNA that we observe upon T-cell activation.…”

“…More recently, the role of miR-21 has been explored in primary human T-lymphocytes showing that miR-21 plays opposing roles in naïve and memory Tcells [29]. Furthermore, transfection of primary murine lymphocytes with miR-21 suggested that this miRNA might boost T-cell activation [30]. However, a loss of function approach in mice has shown that miR-21 limits immune response-mediated activation of the IL-12/IFN-gamma pathway and Th1 polarization [7].…”

Nasopharyngeal cancer-derived microRNA-21 promotes immune suppressive B cells

“…12 It is reported that miR-21 regulates lymphocyte function. 13 Based on the above information, we hypothesize that miR-21 facilitate the development of regulatory immune cells. In this study, we observed that NPC cells produced miR-21, which induced the development of IL-10-producing B cells; the latter showed the capacity to suppress cytotoxic CD8 1 T-cell activities.…”

Role of microRNA-21 in atherogenesis.

“…Moreover parallel with miR-21 induction in various immune cell types, in vivo studies of diseased tissue often display increased expression of miR-21 relative to healthy control tissue. This has been shown in different models of allergic airway inflammation [203,205], psoriasis, atopic eczema [206], and osteoarthritis [198,199,208,209].…”

“…Beyond its direct effects on macrophages, miR-21 was shown as marker of activated Tcells [198,199,208,209]. Interestingly, T-cells transfected with miR-21 acquire a more cytokine-cytokine receptor interaction [212].…”