Mex3a Marks a Slowly Dividing Subpopulation of Lgr5+ Intestinal Stem Cells

Publication date: Available online 9 March 2017
Source:Cell Stem Cell
Author(s): Francisco M. Barriga, Elisa Montagni, Miyeko Mana, Maria Mendez-Lago, Xavier Hernando-Momblona, Marta Sevillano, Amy Guillaumet-Adkins, Gustavo Rodriguez-Esteban, Simon J.A. Buczacki, Marta Gut, Holger Heyn, Douglas J. Winton, Omer H. Yilmaz, Camille Stephan-Otto Attolini, Ivo Gut, Eduard Batlle
Highly proliferative Lgr5+ stem cells maintain the intestinal epithelium and are thought to be largely homogeneous. Although quiescent intestinal stem cell (ISC) populations have been described, the identity and features of such a population remain controversial. Here we report unanticipated heterogeneity within the Lgr5+ ISC pool. We found that expression of the RNA-binding protein Mex3a labels a slowly cycling subpopulation of Lgr5+ ISCs that contribute to all intestinal lineages with distinct kinetics. Single-cell transcriptome profiling revealed that Lgr5+ cells adopt two discrete states, one of which is defined by a Mex3a expression program and relatively low levels of proliferation genes. During homeostasis, Mex3a+ cells continually shift into the rapidly dividing, self-renewing ISC pool. Chemotherapy and radiation preferentially target rapidly dividing Lgr5+ cells but spare the Mex3a-high/Lgr5+ population, helping to promote regeneration of the intestinal epithelium following toxic insults. Thus, Mex3a defines a reserve-like ISC population within the Lgr5+ compartment.

Graphical abstract

Teaser

Lgr5+ intestinal stem cells are considered to be a homogeneous and rapidly proliferating population. Barriga et al. show that the RNA binding protein Mex3a defines a subset of slowly proliferating Lgr5+ cells that contribute to all intestinal lineages with slow kinetics, are resistant to chemotherapy, and support intestinal regeneration.


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