title: Epidermal growth factor suppresses intestinal epithelial cell shedding through a MAPK-dependent pathway.
abstract: Cell shedding from the intestinal villus is a key element of tissue turnover that is essential to maintain health and homeostasis. However, the signals regulating this process are not well understood. We asked whether shedding is controlled by epidermal growth factor receptor (EGFR), an important driver of intestinal growth and differentiation. In 3D ileal enteroid culture and cell culture models (MDCK, IEC-6 and IPEC-J2 cells), extrusion events were suppressed by EGF, as determined by direct counting of released cells or rhodamine-phalloidin labeling of condensed actin rings. Blockade of the MEK-ERK pathway, but not other downstream pathways such as phosphoinositide 3-kinase (PI3K) or protein kinase C (PKC), reversed EGF inhibition of shedding. These effects were not due to a change in cell viability. Furthermore, EGF-driven MAPK signaling inhibited both caspase-independent and -dependent shedding pathways. Similar results were found in vivo, in a novel zebrafish model for intestinal epithelial shedding. Taken together, the data show that EGF suppresses cell shedding in the intestinal epithelium through a selective MAPK-dependent pathway affecting multiple extrusion mechanisms. EGFR signaling might be a therapeutic target for disorders featuring excessive cell turnover, such as inflammatory bowel diseases.
authors.affiliation: Department of Pediatrics, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
authors.forename: Jennifer C
authors.identifier: 0000-0001-5745-2241
authors.initials: JC
authors.lastname: Miguel
authors.affiliation: Department of Pediatrics, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
authors.forename: Adrienne A
authors.identifier: 0000-0003-1078-5473
authors.initials: AA
authors.lastname: Maxwell
authors.affiliation: Department of Pediatrics, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
authors.forename: Jonathan J
authors.identifier: 0000-0002-7213-7992
authors.initials: JJ
authors.lastname: Hsieh
authors.affiliation: Department of Medicine, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7UQ, UK.
authors.forename: Lukas C
authors.initials: LC
authors.lastname: Harnisch
authors.affiliation: Department of Surgery, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
authors.forename: Denise
authors.initials: D
authors.lastname: Al Alam
authors.affiliation: Department of Pediatrics, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.|Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA.
authors.forename: D Brent
authors.initials: DB
authors.lastname: Polk
authors.affiliation: Department of Surgery, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.|Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA.
authors.forename: Ching-Ling
authors.initials: CL
authors.lastname: Lien
authors.affiliation: Department of Medicine, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7UQ, UK mfrey@chla.usc.edu alastair.watson@uea.ac.uk.
authors.forename: Alastair J M
authors.initials: AJ
authors.lastname: Watson
authors.affiliation: Department of Pediatrics, University of Southern California Keck School of Medicine and The Saban Research Institute at Children's Hospital Los Angeles, Los Angeles, CA 90027, USA mfrey@chla.usc.edu alastair.watson@uea.ac.uk.|Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA.
authors.forename: Mark R
authors.identifier: 0000-0002-2561-5402
authors.initials: MR
authors.lastname: Frey
mesh_terms: D000818:Animals; D061945:Caspase Inhibitors / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D004285:Dogs; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D007422:Intestines / Q000166:cytology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015027:Zebrafish; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D061945:Caspase Inhibitors; D047428:Protein Kinase Inhibitors; D004815:Epidermal Growth Factor; D020929:Mitogen-Activated Protein Kinase Kinases; D020169:Caspases; D020741:rho GTP-Binding Proteins
keywords: Cell shedding; EGFR; Epidermal growth factor receptor; Epithelial cell; Inflammatory bowel disease; Intestinal epithelium; MAP kinases; MAPKs