| First Author | Singh Y | Year | 2016 |
| Journal | Immunology | Volume | 149 |
| Issue | 1 | Pages | 74-86 |
| PubMed ID | 27278750 | Mgi Jnum | J:249815 |
| Mgi Id | MGI:5923178 | Doi | 10.1111/imm.12631 |
| Citation | Singh Y, et al. (2016) MicroRNAs regulate T-cell production of interleukin-9 and identify hypoxia-inducible factor-2alpha as an important regulator of T helper 9 and regulatory T-cell differentiation. Immunology 149(1):74-86 |
| abstractText | MicroRNAs (miRNAs) regulate many aspects of helper T cell (Th) development and function. Here we found that they are required for the suppression of interleukin-9 (IL-9) expression in Th9 cells and other Th subsets. Two highly related miRNAs (miR-15b and miR-16) that we previously found to play an important role in regulatory T (Treg) cell differentiation were capable of suppressing IL-9 expression when they were over-expressed in Th9 cells. We used these miRNAs as tools to identify novel regulators of IL-9 expression and found that they could regulate the expression of Epas1, which encodes hypoxia-inducible factor (HIF)-2alpha. HIF proteins regulate metabolic pathway usage that is important in determining appropriate Th differentiation. The related protein, HIF-1alpha enhances Th17 differentiation and inhibits Treg cell differentiation. Here we found that HIF-2alpha was required for IL-9 expression in Th9 cells, but its expression was not sufficient in other Th subsets. Furthermore, HIF-2alpha suppressed Treg cell differentiation like HIF-1alpha, demonstrating both similar and distinct roles of the HIF proteins in Th differentiation and adding a further dimension to their function. Ironically, even though miR-15b and miR-16 suppressed HIF-2alpha expression in Treg cells, inhibiting their function in Treg cells did not lead to an increase in IL-9 expression. Therefore, the physiologically relevant miRNAs that regulate IL-9 expression in Treg cells and other subsets remain unknown. Nevertheless, the analysis of miR-15b and miR-16 function led to the discovery of the importance of HIF-2alpha so this work demonstrated the utility of studying miRNA function to identify novel regulatory pathways in helper T-cell development. |
