Protein complexes associated with β‐catenin differentially influence the differentiation profile of neonatal and adult CD8 + T cells
The canonical Wnt signaling pathway is a master cell regulator involved in CD8+ T cell proliferation and differentiation. In human CD8+ T cells, this pathway induces differentiation into memory cells or a “stem cell memory like” population, which is preferentially present in cord blood. To better understand the role of canonical Wnt signals in neonatal or adult blood, we compared the proteins associated with β‐catenin, in nonstimulated and Wnt3a‐stimulated human neonatal and adult naive CD8+ T cells. Differentially recruited proteins established different complexes in adult and neonatal cells. In the former, β‐catenin‐associated proteins were linked to cell signaling and immunological functions, whereas those of neonates were linked to proliferation and metabolism. Wnt3a stimulation led to the recruitment and overexpression of Wnt11 in adult cells and Wnt5a in neonatal cells, suggesting a differential connexion with planar polarity and Wnt/Ca2+ noncanonical pathways, respectively. The chromatin immunoprecipitation polymerase chain reaction β‐catenin was recruited to a higher level on the promoters of cell renewal genes in neonatal cells and of differentiation genes in those of adults. We found a preferential association of β‐catenin with CBP in neonatal cells and with p300 in the adult samples, which could be involved in a higher self‐renewal capacity of the neonatal cells and memory commitment in those of adults. Altogether, our results show that different proteins associated with β‐catenin during Wnt3a activation mediate a differential response of neonatal and adult human CD8+ T cells.