FOXC1 and FOXC2 promote endothelial-derived R-spondin 3 and CXCL12 signals in intestinal regeneration after ischemia-reperfusion injury

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. The 10X Genomics Chromium platform was used to obtain single cell transcriptomes from the distal jejuna of two control mice and two endothelial cell-specific Foxc1 and Foxc2 compound knockout mice 18.5 hours after small intestinal ischemia and reperfusion injury.