Background: MicroRNA-126 (miR-126), a distinct miRNA family member, has been reported to be involved in the development and function of some types of immune cells. However, the potential role of miR-126 in the development of CD4+ T cells remains to be elucidated.
Objectives: To investigate the potential role of miR-126 in the development of CD4+ T cells in the thymus and explore its significance.
Methods: The relative expression level of miR-126 in thymus CD4+ single-positive (SP) cells was detected by Real-Time PCR assay. The possible change in thymus tissue was assessed by histopathology. The total cell number of thymocytes and the expression of activation-associated molecules including CD62L, CD69, and CD44, as well as proliferation-associated nuclear antigen Ki-67, in CD4+ SP cells were assessed by flow cytometric analysis. The expression of IRS-1 and related signaling pathways including Akt and Erk were determined by flow cytometric analysis.
Results: Compared with that in wild-type (WT) mice, the total cell number of thymocytes in miR-126 knockdown (KD) mice increased significantly. Moreover, the proportion and absolute cell number of thymic CD4+ SP cells decreased significantly in miR-126 KD mice. Further analysis showed that the frequencies of activation-associated molecules including CD62L, CD69, and CD44, as well as proliferation-associated nuclear antigen Ki-67 in CD4+ SP cells also changed significantly, respectively. Mechanism aspect, the expression level of IRS-1, a putative target of miR-126, increased significantly in CD4+ SP cells in miR-126 KD mice. Moreover, the expression levels of the signaling molecules phosphorylated (p)-Akt and p-Erk also changed significantly.
Conclusions: Our work is the first to reveal a previously unknown role of miR-126 in the development of CD4+ SP cells in the thymus, which might ultimately benefit studies on development of thymocytes.
Keywords: IRS-1; Knockdown; MicroRNA-126; SP cells; Thymus.
© 2018 S. Karger AG, Basel.