Dysfunction of S100A4+ effector memory CD8+ T cells aggravates asthma

Progressive loss of effector functions, especially IFN-? secreting capability, in effector memory CD8+ T (CD8+ TEM) cells plays a causal role in asthma worsening. However, the mechanisms of CD8+ TEM cell dysfunction remain elusive. Here, we report that S100A4 drives CD8+ TEM cell dysfunction, impairing their protective memory response and promoting asthma worsening in OVA-induced asthma model. We find that allergic CD8+ TEM cells contain two subsets based on S100A4 expression. S100A4+ subsets exhibit dysfunctional effector phenotypes with increased proliferative capability, whereas S100A4- subsets retain effector function but are more inclined to apoptosis, giving rise a dysfunctional CD8+ TEM cell pool. Mechanistically, S100A4 upregulation of mitochondrial metabolism results in a decrease of acetyl-CoA levels, which impair the transcription of effector genes, especially ifn-?, facilitating cell survival, tolerance and memory potential. Our findings thus reveal general insights into how S100A4 reprograms CD8+ TEM cells into dysfunctional and less protective phenotypes to promote asthma worsening. Overall design: Protein-coding mRNA sequencing (RNA-seq) analysis of S100A4+ and S100A4- CD8+ TEM cells. There were three samples for each cell population.