eIF5A maintains intestinal epithelial homeostasis by sustaining intestinal stem cells.

Intestinal homeostasis is sustained by self-renewal of intestinal stem cells (ISCs), which continuously divide and produce proliferative transit-amplifying (TA) and then progenitor cells. Eukaryotic translation initiation factor 5A (eIF5A), a conserved translation factor, involves in a variety of cellular processes, yet its role in intestinal homeostasis remains unclear. Here, we demonstrate that eIF5A is indispensable for maintaining intestinal epithelial homeostasis. Conditional knockout of Eif5a in the adult mouse intestinal epithelium leads to stem cell loss, suppressed cell proliferation, and increased apoptosis within the crypts, concurrent with shortened gut length, reduced mouse body weight and rapid animal mortality. Consistently, Eif5a deletion in intestinal organoids also exhibits resembling cellular phenotypes. Mass spectrometry analysis reveals a significant downregulation of mitochondrial proteins, particularly those involved in mitochondrial translation, upon eIF5A depletion. Analysis of a published single-cell RNA sequencing dataset shows that mitochondrial translation-related genes, including Dars2, are highly expressed in ISC, TA and progenitor cells. Furthermore, eIF5A-deficient organoids exhibit impaired mitochondrial function, characterized by reduced ATP levels and increased reactive oxygen species (ROS). These findings highlight a critical role for eIF5A in sustaining intestinal epithelial homeostasis by regulating mitochondrial translation, providing a new insight into the molecular mechanism underlying intestinal stem cell renewal and tissue maintenance.