Over- And Ectopic-Expression Of FoxN1 At Early Life Adversely Influences Lymphopoiesis

The study investigated the effects of over- and ectopic-expression of FoxN1 at early life stages using R26-STOPflox-FoxN1 mutant mice. It was found that prenatal over-expression of FoxN1 led to a lethal phenotype in newborns, characterized by abnormal skin permeability. Additionally, progressive FoxN1 expression in infant mice negatively impacted thymic epithelial cell development and T- and B-lymphopoiesis. While FoxN1 over-expression in adult mice could delay thymic aging, early induction in infants adversely affected thymocyte and hair follicle development. Thus, FoxN1 expression had stage and tissue-specific sensitivity, with early over-expression detrimentally influencing immature thymic, T-, and B-cell, and skin epithelial development.