MicroRNA overexpression in slow transit constipation leads to reduced NaV1.5 current and altered smooth muscle contractility. Issue 5 (22nd November 2019)

• Record Type: Journal Article
• Authors: Mazzone, Amelia; Strege, Peter R; Gibbons, Simon J; Alcaino, Constanza; Joshi, Vikram; Haak, Andrew J; Tschumperlin, Daniel J; Bernard, Cheryl E; Cima, Robert R; Larson, David W; Chua, Heidi K; Graham, Rondell P; El Refaey, Mona; Mohler, Peter J; Hayashi, Yujiro; Ordog, Tamas; Calder, Stefan; Du, Peng; Farrugia, Gianrico; Beyder, Arthur
• Is Part Of: Gut. Volume 69:Issue 5(2020)
• Page Start: 868
• Page End: 876
• Publication Date: 2019-11-22
• Subjects: motility disorders -- intestinal motility -- intestinal ion transport -- genetics -- constipation; Gastroenterology -- Periodicals; 616.33
• DOI: 10.1136/gutjnl-2019-318747
• Languages: English
• ISSNs: 0017-5749

Abstract

Abstract : Objective: This study was designed to evaluate the roles of microRNAs (miRNAs) in slow transit constipation (STC). Design: All human tissue samples were from the muscularis externa of the colon. Expression of 372 miRNAs was examined in a discovery cohort of four patients with STC versus three age/sex-matched controls by a quantitative PCR array. Upregulated miRNAs were examined by quantitative reverse transcription qPCR (RT-qPCR) in a validation cohort of seven patients with STC and age/sex-matched controls. The effect of a highly differentially expressed miRNA on a custom human smooth muscle cell line was examined in vitro by RT-qPCR, electrophysiology, traction force microscopy, and ex vivo by lentiviral transduction in rat muscularis externa organotypic cultures. Results: The expression of 13 miRNAs was increased in STC samples. Of those miRNAs, four were predicted to target SCN5A, the gene that encodes the Na + channel NaV 1.5. The expression of SCN5A mRNA was decreased in STC samples. Let-7f significantly decreased Na + current density in vitro in human smooth muscle cells. In rat muscularis externa organotypic cultures, overexpression of let-7f resulted in reduced frequency and amplitude of contraction. Conclusions: A small group of miRNAs is upregulated in STC, and many of these miRNAs target the SCN5A-encoded Na + channel NaV 1.5. Within this set, a novel NaV 1.5 regulator, let-7f, resulted in decreased NaV 1.5 expression, current density and reduced motility of GI smooth muscle. These results suggest NaV 1.5 and miRNAs as novel diagnostic and potential therapeutic targets in STC.