Intestinal ischemia induces mucosal damage while simultaneously activating intestinal stem cells (ISCs), which subsequently regenerate the damaged intestinal epithelium. However, whether angiocrine factors secreted from vascular endothelial cells (ECs) - blood and lymphatic ECs (BECs and LECs, respectively) – regulate ISC-mediated regeneration have yet to be elucidated. Here, we identify FOXC1 and FOXC2 as essential regulators of angiocrine signaling in regeneration of the small intestine after ischemia-reperfusion (I/R) injury. EC- and LEC-specific deletions of Foxc1, Foxc2, or both in mice augment I/R-induced intestinal damage by causing defects in vascular regrowth, expression of the chemokine CXCL12 and the Wnt activator R-spondin 3 in BECs and LECs, respectively, and activation of Wnt signaling in ISCs. Treatment with CXCL12 and R-spondin 3 rescues the I/R-induced intestinal damage in EC- and LEC-Foxc mutant mice, respectively. This study provides evidence that FOXC1 and FOXC2 are required for intestinal regeneration by stimulating angiocrine CXCL12 and Wnt signaling.

Impaired development and maintenance of Schlemm’s canal (SC) are associated with perturbed aqueous humor outflow and intraocular pressure. The angiopoietin (ANGPT)/TIE2 signaling pathway regulates SC development and maintenance, whereas the molecular mechanisms of crosstalk between SC and the neural crest (NC)-derived neighboring tissue, the trabecular meshwork (TM), are poorly understood. Here, we show NC-specific forkhead box (Fox)c2deletion in mice results in impaired SC morphogenesis, loss of SC identity, and elevated intraocular pressure. Visible-light optical coherence tomography analysis further demonstrated functional impairment of the SC in response to changes in intraocular pressure in NC-Foxc2-/-mice, suggesting altered TM biomechanics. Single-cell RNA-sequencing analysis identified that this phenotype is predominately characterized by transcriptional changes associated with extracellular matrix organization and stiffness in TM cell clusters, including increased matrix metalloproteinase expression, which can cleave the TIE2 ectodomain to produce soluble TIE2. Moreover, endothelial-specificFoxc2deletion impaired SC morphogenesis because of reduced TIE2 expression, which was rescued by deleting the TIE2 phosphatase VE-PTP. Thus, Foxc2 is critical in maintaining SC identity and morphogenesis via TM–SC crosstalk.