FoxL1 mesenchymal cells are a critical source of Wnt5a for midgut elongation during mouse embryonic intestinal development.

Wnt5a is a non-canonical Wnt ligand that is essential for normal embryonic development in mammals. The role of Wnt5a in early intestinal development has been examined in gene ablation models, where Wnt5a mice exhibit strikingly shortened intestines. However, the exact cellular source of Wnt5a has remained elusive, until a recent study found that FoxL1-expressing mesenchymal cells (FoxL1 cells), which are localized directly beneath the intestinal epithelium, express Wnt5a.