NFATc1 Regulation of TRAIL Expression in Human Intestinal Cells

Qingding Wang,Chi-Wing Chow,Heidi L Weiss,B Mark Evers,Yuning Zhou

doi:10.1371/journal.pone.0019882

Qingding Wang, Chi-Wing Chow + Show 3 more

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https://doi.org/10.1371/journal.pone.0019882

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Abstract

TNF-related apoptosis-inducing ligand (TRAIL; Apo2) has been shown to promote intestinal cell differentiation. Nuclear factor of activated T cells (NFAT) participates in the regulation of a variety of cellular processes, including differentiation. Here, we examined the role of NFAT in the regulation of TRAIL in human intestinal cells. Treatment with a combination of phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187 (Io) increased NFAT activation and TRAIL expression; pretreatment with the calcineurin inhibitor cyclosporine A (CsA), an antagonist of NFAT signaling, diminished NFAT activation and TRAIL induction. In addition, knockdown of NFATc1, NFATc2, NFATc3, and NFATc4 blocked PMA/Io increased TRAIL protein expression. Expression of NFATc1 activated TRAIL promoter activity and increased TRAIL mRNA and protein expression. Deletion of NFAT binding sites from the TRAIL promoter did not significantly abrogate NFATc1-increased TRAIL promoter activity, suggesting an indirect regulation of TRAIL expression by NFAT activation. Knockdown of NFATc1 increased Sp1 transcription factor binding to the TRAIL promoter and, importantly, inhibition of Sp1, by chemical inhibition or RNA interference, increased TRAIL expression. These studies identify a novel mechanism for TRAIL regulation by which activation of NFATc1 increases TRAIL expression through negative regulation of Sp1 binding to the TRAIL promoter.

Highlights

The mammalian intestinal mucosa undergoes a process of continual renewal, characterized by active proliferation of stem cells localized near the base of the crypts, progression of these cells up the crypt-villus axis with cessation of proliferation and subsequent differentiation into one of the four primary cell types [1]
Nuclear factor of activated T cells (NFAT) activation increases Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression in HT29 cells Previously, we have shown that inhibition of PI3-kinase, which augments enterocyte-like differentiation of HT29 and Caco-2 human colon cancer cells [9], increased TRAIL expression [10]
NFAT transcription factors bind to the TRAIL promoter, our results showed that NFATc1 increased TRAIL promoter activity independent of direct binding to the promoter

Summary

Introduction

The mammalian intestinal mucosa undergoes a process of continual renewal, characterized by active proliferation of stem cells localized near the base of the crypts, progression of these cells up the crypt-villus axis with cessation of proliferation and subsequent differentiation into one of the four primary cell types [1]. Exposure of the fetal human intestine cell line, tsFHI, to recombinant TRAIL increased the expression levels of the canonical differentiation marker dipeptidylpeptidase IV (DPPIV) and the cyclin-dependent kinase inhibitors p21Waf and p27Kip1 [11], which mediate the induction of growth arrest and the stabilization of differentiated traits, respectively. Together, these studies demonstrate an important role for TRAIL in the regulation of intestinal cell differentiation

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