Prophylactic inhibition of LATS1/2 before high-dose irradiation promotes the regeneration of the damaged intestinal epithelium.

Abstract

Following radiation injury, intestinal epithelial cells adapt through cellular plasticity to regenerate and repopulate the damaged epithelium by activating Yap, a key effector protein of the Hippo signaling pathway. However, the impact of pharmacologically targeting the Hippo pathway on the regeneration of the irradiated intestinal epithelium remains poorly understood. Here, we investigated this question using NCGC-023, a selective and potent small-molecule inhibitor of Yap's upstream regulators LATS1/2. NCGC-023 treatment significantly increased active Yap protein expression in human enteroids and protected them against ionizing radiation (IR) in vitro. In mice, transient treatment with NCGC-023 before IR reduced radiation-induced DNA damage, suppressed premitotic apoptosis and aberrant mitosis in intestinal crypt cells, facilitated regenerative reprogramming of the damaged intestinal epithelium, and improved survival of mice subjected to IR doses that precipitate gastrointestinal acute radiation syndrome (GI-ARS). Mechanistically, NCGC-023 treatment before IR upregulated key signaling pathways controlled by LATS1/2, including Yap-dependent regenerative responses involving Il-33 and Yap-independent cellular responses to heavy metals mediated by metallothioneins. Moreover, NCGC-023 treatment did not exacerbate delayed injury in multiple organs of mice that survived 4 months post-irradiation. Together, these results demonstrate that transient NCGC-023 treatment before high-dose IR promotes the regeneration of the damaged intestinal epithelium. This proof-of-concept study supports further development of LATS1/2 inhibitors as prophylactic medical countermeasures for GI-ARS.