Ghrelin ameliorates TNF-a induced anti-proliferative and pro-apoptotic effects and promotes intestinal epithelial restitution

Abstract

Abstract Introduction: TNF-a is one of the major cytokine released by the invading mucosal leukocytes during acute exacerbations of inflammatory bowel disease (IBD). It interferes with the inherent restitutive potential of mucosal epithelial cells through inhibition of proliferation, cell migration and induction of cellular apoptosis. Ghrelin is a recently discovered peptide with mitogenic and anti-apoptotic properties. We hypothesized that ghrelin would modulate the TNF-a induced anti-proliferative, anti-migratory and pro-apoptotic effects to enhance mucosal healing in IBD. Methods: Non-transformed and transformed intestinal epithelial cell lines (FHs74Int, IEC-6 & Caco-2) were treated with TNF-a, ghrelin and ghrelin receptor antagonist in the presence or absence of specific cAMP, PI3K, EGFR, ERK1/2 inhibitors. Proliferation was determined by MTT assay, apoptosis by TUNEL staining and epithelial restitution by Podolsky's cell monolayer repair assay. Western blotting was employed to assess ghrelin's cytoprotective and prolifer ative role in the presence of TNF-a in relation to EGFR, PI3K/Akt, ERK1/2 pathways and caspase-3 profiling. Results: Ghrelin abrogates high dose TNF-alpha induced anti-proliferative and pro-apoptotic effects (p Conclusions: Ghrelin abolishes TNF-a induced anti-proliferative and pro-apoptotic effects and promotes intestinal epithelial restitutive behavior. Therapeutic utility of ghrelin in mucosal protection and regeneration in IBD warrants further investigation.