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- Title
HTLV-1 Tax-Mediated Inhibition of FOXO3a Activity Is Critical for the Persistence of Terminally Differentiated CD4<sup>+</sup> T Cells.
- Authors
Olagnier, David; Sze, Alexandre; Bel Hadj, Samar; Chiang, Cindy; Steel, Courtney; Han, Xiaoying; Routy, Jean-Pierre; Lin, Rongtuan; Hiscott, John; van Grevenynghe, Julien
- Abstract
The mechanisms involved in the persistence of activated CD4+ T lymphocytes following primary human T leukemia/lymphoma virus type 1 (HTLV-1) infection remain unclear. Here, we demonstrate that the HTLV-1 Tax oncoprotein modulates phosphorylation and transcriptional activity of the FOXO3a transcription factor, via upstream activation of the AKT pathway. De novo HTLV-1 infection of CD4+ T cells or direct lentiviral-mediated introduction of Tax led to AKT activation and AKT-dependent inactivation of FOXO3a, via phosphorylation of residues Ser253 and Thr32. Inhibition of FOXO3a signalling led to the long-term survival of a population of highly activated, terminally differentiated CD4+Tax+CD27negCCR7neg T cells that maintained the capacity to disseminate infectious HTLV-1. CD4+ T cell persistence was reversed by chemical inhibition of AKT activity, lentiviral-mediated expression of a dominant-negative form of FOXO3a or by specific small interfering RNA (siRNA)-mediated silencing of FOXO3a. Overall this study provides new mechanistic insight into the strategies used by HTLV-1 to increase long-term maintenance of Tax+CD4+ T lymphocytes during the early stages of HTLV-1 pathogenesis.
- Subjects
T cells; LYMPHOCYTES; LEUKEMIA; HTLV-I infections; LYMPHOMAS
- Publication
PLoS Pathogens, 2014, Vol 10, Issue 12, p1
- ISSN
1553-7366
- Publication type
Article
- DOI
10.1371/journal.ppat.1004575