Induction of protective vaccine responses, governed by the successful generation of antigen-specific antibodies and long-lived memory T cells, is increasingly impaired with age. Regulation of the T cell proteome by a dynamic network of microRNAs is crucial to T cell responses. Here, we show that activation-induced upregulation of miR-21 biases the transcriptome of differentiating T cells away from memory T cells and toward inflammatory effector T cells. Such a transcriptome bias is also characteristic of T cell responses in older individuals who have increased miR-21 expression and is reversed by antagonizing miR-21. miR-21 targets negative feedback circuits in several signaling pathways. The concerted, sustained activity of these signaling pathways in miR-21high T cells disfavors the induction of transcription factor networks involved in memory cell differentiation. Our data suggest that curbing miR-21 upregulation or activity in older individuals may improve their ability to mount effective vaccine responses. A hallmark of the aging immune system is its failure to induce long-lived memory. Kim et al. report that increased expression of miR-21 in naive T cells from older individuals sustains signaling in the MAPK and AKT-mTORC pathways, disfavoring induction of transcription factor networks involved in memory cell generation.
Bibliographical noteFunding Information:
We thank Corey Cain, Lusijah Sutherland, and the Palo Alto VA Flow Cytometry Core for assistance with flow cytometry and cell sorting. This work was supported by the NIH ( R01 AR042527 , R01 HL117913 , R01 AI108906 , and P01 HL129941 to C.M.W. and R01 AI108891 , R01 AG045779 , U19 AI057266 , R01 AI129191 , and I01 BX001669 to J.J.G.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
© 2018 The Authors
- T cell differentiation
- T memory cell
- immune aging
- short-lived T effector cell
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)