The dynamic role of ufmylation in endothelium

Endothelial cells not only form a physical barrier but also play key roles in vascular homeostasis by regulating vascular tone, hemostasis, and inflammatory response. Understanding new mechanisms underlying endothelial homeostasis can unlock novel strategies for combating cardiovascular diseases. Ubiquitin-fold modifier 1 (UFM1) is an ubiquitin-like protein that covalently modifies protein substrates via a highly conserved E1 (UBA5)-E2 (UFC1)-E3 (UFL1) enzymatic cascade. However, the molecular mechanisms by which ufmylation regulates endothelial function remain elusive. Interestingly, we observed that the UFL1 locus is significantly associated with coronary artery diseases, which implies the importance of ufmylation in vascular diseases. Here, we hypothesized that ufmylation in endothelial cells is indispensable for vascular development. We generated pan endothelial-specific E3 (UFL1) knockout (UFL1 ECKO ) mice using Cdh5 Cre mice. UFL1 deficient mice showed perinatal lethality at P0. E16.5 UFL1 ECKO embryos showed severe hemorrhage and disrupted blood vessel formation suggesting defects in angiogenesis. To gain mechanistic insights into the function of ufmylation in endothelial cells, we silenced UFL1 and UFM1 in human umbilical vein endothelial cells (HUVECs). We found that silencing UFL1 and UFM1 impaired cell viability, suppressed cell proliferation and endothelial migration, suggesting an indispensable role of ufmylation in vascular development. Bulk-RNA sequencing of UFL1 and UFM1 deficient HUVECs showed that differentially expressed genes (DEGs) were mostly enriched in cell cycle and inflammatory response gene sets. Tamoxifen-inducible UFL1 ECKO mice show decreased cardiac functions. Overall, our results indicate that ufmylation is essential for endothelial cell homeostasis to maintain angiogenesis. 700000-20300-04250000-12200-61100-NHLBI0027 700000-20300-04250000-12100-64076-AHA00235 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.