Stress responsive miR-31 is a major modulator of mouse intestinal stem cells during regeneration and tumorigenesis.

Abstract

Intestinal regeneration and tumorigenesis are believed to be driven by intestinal stem cells (ISCs). Elucidating mechanisms underlying ISC activation during regeneration and tumorigenesis can help uncover the underlying principles of intestinal homeostasis and disease including colorectal cancer. Here we show that <i>miR-31</i> drives ISC proliferation, and protects ISCs against apoptosis, both during homeostasis and regeneration in response to ionizing radiation injury. Furthermore, <i>miR-31</i> has oncogenic properties, promoting intestinal tumorigenesis. Mechanistically, <i>miR-31</i> acts to balance input from Wnt, BMP, TGFβ signals to coordinate control of intestinal homeostasis, regeneration and tumorigenesis. We further find that <i>miR-31</i> is regulated by the STAT3 signaling pathway in response to radiation injury. These findings identify <i>miR-31</i> as a critical modulator of ISC biology, and a potential therapeutic target for a broad range of intestinal regenerative disorders and cancers.