Neurotensin-induced miR-133? expression regulates neurotensin receptor 1 recycling through its downstream target aftiphilin.

ABSTRACT: Neurotensin (NT) triggers signaling in human colonic epithelial cells by activating the G protein-coupled receptor, the neurotensin receptor 1 (NTR1). Activated NTR1 traffics from the plasma membrane to early endosomes, and then recycles. Although sustained NT/NTR1 signaling requires efficient NTR1 recycling, little is known about the regulation of NTR1 recycling. We recently showed that NT/NTR1 signaling increases expression of miR-133?. Herein, we studied the mechanism of NT-regulated miR-133? expression and examined the role of miR-133? in intracellular NTR1 trafficking in human NCM460 colonocytes. We found that NT-induced miR-133? upregulation involves the negative transcription regulator, zinc finger E-box binding homeobox 1. Silencing of miR-133? or overexpression of aftiphilin (AFTPH), a binding target of miR-133?, attenuated NTR1 trafficking to plasma membrane in human colonocytes, without affecting NTR1 internalization. We localized AFTPH to early endosomes and the trans-Golgi network (TGN) in unstimulated human colonic epithelial cells. AFTPH overexpression reduced NTR1 localization in early endosomes and increased expression of proteins related to endosomes and the TGN trafficking pathway. AFTPH overexpression and de-acidification of intracellular vesicles increased NTR1 expression. Our results suggest a novel mechanism of GPCR trafficking in human colonic epithelial cells by which a microRNA, miR-133? regulates NTR1 trafficking through its downstream target AFTPH.

SUBMITTER: Law IK 

PROVIDER: S-EPMC4763298 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature