Polarizing intestinal epithelial cells electrically through Ror2.

Lin Cao,Roderick H Scott,Min Zhao,Colin D Mccaig,Jin Pu,Gillian Milne,Hans Clevers,Siwei Zhao

doi:10.1242/jcs.146357

Abstract

ABSTRACTThe apicobasal polarity of enterocytes determines where the brush border membrane (apical membrane) will form, but how this apical membrane faces the lumen is not well understood. The electrical signal across the epithelium could serve as a coordinating cue, orienting and polarizing enterocytes. Here, we show that applying a physiological electric field to intestinal epithelial cells, to mimic the natural electric field created by the transepithelial potential difference, polarized phosphorylation of the actin-binding protein ezrin, increased expression of intestinal alkaline phosphatase (ALPI, a differentiation marker) and remodeled the actin cytoskeleton selectively on the cathode side. In addition, an applied electric field also activated ERK1/2 and LKB1 (also known as STK11), key molecules in apical membrane formation. Disruption of the tyrosine protein kinase transmembrane receptor Ror2 suppressed activation of ERK1/2 and LKB1 significantly, and subsequently inhibited apical membrane formation in enterocytes. Our findings indicate that the endogenous electric field created by the transepithelial potential difference might act as an essential coordinating signal for apical membrane formation at a tissue level, through activation of LKB1 mediated by Ror2–ERK signaling.

Highlights

Polarization of gut epithelial cells involves the generation of the brush border membrane (BBM) or apical membrane at the luminal side of the intestine
A physiological electric field induces cathodal polarization of intestinal epithelial cells We first mimicked the endogenous electric field established by applying a physiological electric field to cultured enterocytes to test the effects on the formation of polarization
Doxycycline (Dox)-induced LKB1 activity was required to form an apical membrane in single LS174T-W4 intestinal epithelial cells (Baas et al, 2004)

Summary

Introduction

Polarization of gut epithelial cells (enterocytes) involves the generation of the brush border membrane (BBM) or apical membrane at the luminal side of the intestine. Doxycycline (Dox)-induced LKB1 activity was required to form an apical membrane in single LS174T-W4 intestinal epithelial cells (Baas et al, 2004). When LS174T-W4 cells were treated with Dox or an applied physiological electric field plus Dox for 6 hours, 64%63.2 and 70%62.5 (mean6s.e.m.) of cells, respectively, showed an actin cap (apical membrane formation, supplementary material Fig. S2).

Results

Conclusion