Polycomb Repressive Complex 2-Mediated Chromatin Repression Guides Effector CD8+ T Cell Terminal Differentiation and Loss of Multipotency

Publication date: Available online 11 April 2017
Source:Immunity
Author(s): Simon M. Gray, Robert A. Amezquita, Tianxia Guan, Steven H. Kleinstein, Susan M. Kaech
Understanding immunological memory formation depends on elucidating how multipotent memory precursor (MP) cells maintain developmental plasticity and longevity to provide long-term immunity while other effector cells develop into terminally differentiated effector (TE) cells with limited survival. Profiling active (H3K27ac) and repressed (H3K27me3) chromatin in naive, MP, and TE CD8⁺ T cells during viral infection revealed increased H3K27me3 deposition at numerous pro-memory and pro-survival genes in TE relative to MP cells, indicative of fate restriction, but permissive chromatin at both pro-memory and pro-effector genes in MP cells, indicative of multipotency. Polycomb repressive complex 2 deficiency impaired clonal expansion and TE cell differentiation, but minimally impacted CD8⁺ memory T cell maturation. Abundant H3K27me3 deposition at pro-memory genes occurred late during TE cell development, probably from diminished transcription factor FOXO1 expression. These results outline a temporal model for loss of memory cell potential through selective epigenetic silencing of pro-memory genes in effector T cells.

Graphical abstract

Teaser

Cytotoxic CD8⁺ T cells either terminally differentiate and die or form a rapidly responding population of memory T cells after pathogen clearance. Gray et al. define a temporal model for how effector T cells lose memory cell potential through selective epigenetic silencing of pro-memory genes.


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