J Neurogastroenterol Motil.  2018 Oct;24(4):656-668. 10.5056/jnm18037.

MicroRNA-200a Targets Cannabinoid Receptor 1 and Serotonin Transporter to Increase Visceral Hyperalgesia in Diarrhea-predominant Irritable Bowel Syndrome Rats

• Hou Q
• Huang Y
• Zhang C
• Zhu S
• Li P
• Chen X
• Hou Z
• Liu F

• KMID: 2422855
• DOI: http://doi.org/10.5056/jnm18037

Abstract

BACKGROUND/AIMS
MicroRNAs (miRNAs) were reported to be responsible for intestinal permeability in diarrhea-predominant irritable bowel syndrome (IBS-D) rats in our previous study. However, whether and how miRNAs regulate visceral hypersensitivity in IBS-D remains largely unknown.
METHODS
We established the IBS-D rat model and evaluated it using the nociceptive visceral hypersensitivity test, myeloperoxidase activity assay, restraint stress-induced defecation, and electromyographic (EMG) activity. The distal colon was subjected to miRNA microarray analysis followed by isolation and culture of colonic epithelial cells (CECs). Bioinformatic analysis and further experiments, including dual luciferase assays, quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay, were used to detect the expression of miRNAs and how it regulates visceral hypersensitivity in IBS-D rats.
RESULTS
The IBS-D rat model was successfully established. A total of 24 miRNAs were differentially expressed in the distal colon of IBS-D rats; 9 were upregulated and 15 were downregulated. Among them, the most significant upregulation was miR-200a, accompanied by downregulation of cannabinoid receptor 1 (CNR1) and serotonin transporter (SERT). MiR-200a mimic markedly inhibited the expression of CNR1/SERT. Bioinformatic analysis and luciferase assay confirmed that CNR1/SERT are direct targets of miR-200a. Rescue experiments that overexpressed CNR1/SERT significantly abolished the inhibitory effect of miR-200a on the IBS-D rats CECs.
CONCLUSIONS
This study suggests that miR-200a could induce visceral hyperalgesia by targeting the downregulation of CNR1 and SERT, aggravating or leading to the development and progression of IBS-D. MiR-200a may be a regulator of visceral hypersensitivity, which provides potential targets for the treatment of IBS-D.

Keyword

CNR1; Diarrhea; Hypersensitivity; Irritable bowel syndrome; MiR-200a; SERT

MeSH Terms

Animals
Blotting, Western
Colon
Computational Biology
Defecation
Diarrhea
Down-Regulation
Enzyme-Linked Immunosorbent Assay
Epithelial Cells
Hyperalgesia*
Hypersensitivity
Irritable Bowel Syndrome*
Luciferases
Microarray Analysis
MicroRNAs
Models, Animal
Permeability
Peroxidase
Rats*
Real-Time Polymerase Chain Reaction
Receptors, Cannabinoid*
Serotonin Plasma Membrane Transport Proteins*
Serotonin*
Up-Regulation
Luciferases
MicroRNAs
Peroxidase
Receptors, Cannabinoid
Serotonin
Serotonin Plasma Membrane Transport Proteins