Radical and lunatic fringes modulate notch ligands to support mammalian intestinal homeostasis.

Preetish Kadur Lakshminarasimha Murthy,Kuei-Ling Tung,Anastasia Kristine Varanko,Xiling Shen,Fatih Semerci,Matthew S Bochter,Keli Xu,Rui Xi,Tara Srinivasan,Susan E Cole,Mirjana Maletic-Savatic

doi:10.7554/elife.35710

Abstract

Notch signalling maintains stem cell regeneration at the mouse intestinal crypt base and balances the absorptive and secretory lineages in the upper crypt and villus. Here we report the role of Fringe family of glycosyltransferases in modulating Notch activity in the two compartments. At the crypt base, RFNG is enriched in the Paneth cells and increases cell surface expression of DLL1 and DLL4. This promotes Notch activity in the neighbouring Lgr5+ stem cells assisting their self-renewal. Expressed by various secretory cells in the upper crypt and villus, LFNG promotes DLL surface expression and suppresses the secretory lineage . Hence, in the intestinal epithelium, Fringes are present in the ligand-presenting 'sender' secretory cells and promote Notch activity in the neighbouring 'receiver' cells. Fringes thereby provide for targeted modulation of Notch activity and thus the cell fate in the stem cell zone, or the upper crypt and villus.

Highlights

Lgr5+ Crypt Base Columnar cells (CBCs) located at the bottom of the crypts constantly self-renew to maintain the small intestinal epithelium, which is one of the fastest regenerative tissues in the body (Barker et al, 2007; van der Flier et al, 2009)
We analysed previously published microarray data on Lgr5+ CBCs and Paneth cells (Sato et al, 2011) and found that Rfng is significantly upregulated in Paneth cells (Figure 1—figure supplement 1A)
We isolated CBCs and Paneth cells (CD24high/SSChigh) from Lgr5-GFP mice by FACS using an established protocol (Sato et al, 2011; Sato et al, 2009) and found that the Paneth cells are enriched for Rfng (Figure 1A)

Summary

Introduction

Lgr5+ Crypt Base Columnar cells (CBCs) located at the bottom of the crypts constantly self-renew to maintain the small intestinal epithelium, which is one of the fastest regenerative tissues in the body (Barker et al, 2007; van der Flier et al, 2009). CBCs divide and move up the crypt into the progenitor or transit-amplifying zone where the cells rapidly proliferate and terminally differentiate into two major types: absorptive (enterocytes) and secretory (mainly Paneth and goblet cells). Enterocytes and goblet cells populate the villi while the Paneth cells move to the bottom of the crypt and provide a niche for the CBCs (van der Flier et al, 2009). Notch signalling pathway primarily consists of Notch receptors (NOTCH1-4) and ligands (DLL1-4 and JAG1-2) (Bray, 2006). Upon activation of a Notch receptor by a ligand, it undergoes successive cleavages by ADAM/TACE and g-secretase (Bray, 2006). The extracellular domain of the Notch receptor and ligands

Methods

Results

Conclusion