Faculty Collaboration Database

MicroRNA-103a regulates sodium-dependent vitamin C transporter-1 expression in intestinal epithelial cells. J Nutr Biochem 2019 03;65:46-53

Date

01/08/2019

Pubmed ID

30616065

Pubmed Central ID

PMC6420349

DOI

10.1016/j.jnutbio.2018.12.001

Scopus ID

2-s2.0-85059472038   3 Citations

Abstract

Intestinal absorption of ascorbic acid (AA) occurs via a Na⁺-dependent carrier-mediated process facilitated through the human sodium-dependent vitamin C transporters-1 &-2 (hSVCT1 and hSVCT2). Many studies have shown that hSVCT1 (product of the SLC23A1 gene) is expressed on the apical membrane of polarized enterocytes where it mediates AA absorption. hSVCT1 expression levels are therefore an important determinant of physiological vitamin C homeostasis. However, little is known about posttranscriptional mechanisms that regulate hSVCT1 expression in intestinal epithelia. In this study, we investigated regulation of hSVCT1 by microRNA (miRNA). A pmirGLO-SLC23A1-3'-UTR construct transfected into human intestinal cell lines (Caco-2 and NCM460 cells) showed markedly reduced luciferase activity. Bioinformatic analysis of the SLC23A1-3'-UTR predicted five miRNA binding sites (miR-103a, miR-107, miR-328, miR-384, and miR-499-5p) in the 3'-UTR. Expression of mature miR-103a was markedly higher compared to the other four putative miRNA regulators in both intestinal cell lines and mouse jejunal mucosa. Addition of a miR-103a mimic, but not a miR-103a mutant construct, markedly reduced the luminescence of the pmirGLO-SLC23A1-3'-UTR reporter. Reciprocally, addition of a miR-103a inhibitor significantly increased luciferase reporter activity. Addition of the miR-103a mimic led to a significant inhibition in AA uptake, associated with decreased hSVCT1 mRNA and protein expression in Caco-2 cells. In contrast, the miR-103a inhibitor increased AA uptake, associated with increased levels of hSVCT1 mRNA and protein. These findings provide the first evidence for posttranscriptional regulation of hSVCT1 by miRNA in intestinal epithelial cells.

Author List

Subramanian VS, Sabui S, Marchant JS, Said HM

Author

Jonathan S. Marchant PhD Chair, Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

3' Untranslated Regions
Animals
Ascorbic Acid
Caco-2 Cells
Cell Line
Colon
Gene Expression Regulation
Humans
Intestinal Mucosa
Luciferases
Mice, Inbred C57BL
MicroRNAs
Mutation
Sodium-Coupled Vitamin C Transporters