Selenium alters miRNA profile in an intestinal cell line: evidence that miR-185 regulates expression of GPX2 and SEPSH2.
METHODS
Intake of the essential micronutrient selenium (Se) has health implications. This work addressed whether some effects of Se on gene expression are exerted through microRNAs (miRNA).


RESULTS
Human colon adenocarcinoma cells (Caco-2) were grown in Se-deficient or Se-adequate medium for 72 h. RNA was extracted and subjected to analysis of 737 miRNA using microarray technology. One hundred and forty-five miRNA were found to be expressed in Caco-2 cells. Twelve miRNA showed altered expression after Se depletion: miR-625, miR-492, miR-373*, miR-22, miR-532-5p, miR-106b, miR-30b, miR-185, miR-203, miR1308, miR-28-5p, miR-10b. These changes were validated by quantitative real-time PCR (RT-qPCR). Transcriptomic analysis showed that Se depletion altered expression of 50 genes including selenoproteins GPX1, SELW, GPX3, SEPN1, SELK, SEPSH2 and GPX4. Pathway analysis identified arachidonic acid metabolism, glutathione metabolism, oxidative stress, positive acute phase response proteins and respiration of mitochondria as Se-sensitive pathways. Bioinformatic analysis identified 13 transcripts as targets for the Se-sensitive miRNA; three were predicted to be recognised by miR-185. Silencing of miR-185 increased GPX2 and SEPSH2 expression.


CONCLUSIONS
We propose that miR-185 plays a role in up-regulation of GPX2 and SEPHS2 expression. In the case of SEPHS2 this may contribute to maintaining selenoprotein synthesis. The data indicate that micronutrient supply can regulate the cell miRNA expression profile.
Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK; Human Nutrition Research Centre, Newcastle University, Newcastle upon Tyne, UK.
Anabel
A
Maciel-Dominguez
Daniel
D
Swan
Dianne
D
Ford
John
J
Hesketh
D018938:Caco-2 Cells / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D005979:Glutathione Peroxidase / Q000235:genetics*; D006801:Humans; D007422:Intestines / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics*; D010770:Phosphotransferases / Q000235:genetics*; D012643:Selenium / Q000494:pharmacology*; D015854:Up-Regulation
C552431:MIRN185 microRNA, human; D035683:MicroRNAs; C117436:GPX2 protein, human; D005979:Glutathione Peroxidase; D010770:Phosphotransferases; C000591223:selenophosphate synthetase 2, human; D012643:Selenium
Epithelial cells; MicroRNA; Micronutrient; Selenoprotein; Transcriptomics