Di Mitri, Diletta, Azevedo, Rita I., Henson, Sian M., Libri, Valentina, Riddell, Natalie E., Macaulay, Richard, Kipling, David, Soares, Maria V. D., Battistini, Luca and Akbar, Arne N. 2011. Reversible senescence in human CD4+CD45RA+CD27- memory T cells. The Journal of Immunology 187 (5) , pp. 2093-2100. 10.4049/jimmunol.1100978 |
Abstract
Persistent viral infections and inflammatory syndromes induce the accumulation of T cells with characteristics of terminal differentiation or senescence. However, the mechanism that regulates the end-stage differentiation of these cells is unclear. Human CD4+ effector memory (EM) T cells (CD27−CD45RA−) and also EM T cells that re-express CD45RA (CD27−CD45RA+; EMRA) have many characteristics of end-stage differentiation. These include the expression of surface KLRG1 and CD57, reduced replicative capacity, decreased survival, and high expression of nuclear γH2AX after TCR activation. A paradoxical observation was that although CD4+ EMRA T cells exhibit defective telomerase activity after activation, they have significantly longer telomeres than central memory (CM)-like (CD27+CD45RA−) and EM (CD27−CD45RA−) CD4+ T cells. This suggested that telomerase activity was actively inhibited in this population. Because proinflammatory cytokines such as TNF-α inhibited telomerase activity in T cells via a p38 MAPK pathway, we investigated the involvement of p38 signaling in CD4+ EMRA T cells. We found that the expression of both total and phosphorylated p38 was highest in the EM and EMRA compared with that of other CD4+ T cell subsets. Furthermore, the inhibition of p38 signaling, especially in CD4+ EMRA T cells, significantly enhanced their telomerase activity and survival after TCR activation. Thus, activation of the p38 MAPK pathway is directly involved in certain senescence characteristics of highly differentiated CD4+ T cells. In particular, CD4+ EMRA T cells have features of telomere-independent senescence that are regulated by active cell signaling pathways that are reversible.
Item Type: | Article |
---|---|
Date Type: | Publication |
Status: | Published |
Schools: | Medicine |
Subjects: | Q Science > QR Microbiology > QR180 Immunology |
Publisher: | American Association of Immunologists |
ISSN: | 0022-1767 |
Last Modified: | 04 Jun 2017 03:58 |
URI: | https://orca.cardiff.ac.uk/id/eprint/29879 |
Citation Data
Cited 156 times in Scopus. View in Scopus. Powered By Scopus® Data
Actions (repository staff only)
![]() |
Edit Item |