Regulation of Colonic Mucosal MicroRNA Expression via Multiple Targets in Visceral Hypersensitivity Rats by Tongxieyaofang

The role of miRNA in IBS pathogenesis, diagnosis and therapy: The latest thought

IBS is a prevalent clinical condition affecting bowel function. There is a restricted comprehension of its pathogenesis, an absence of particular diagnostic tools, and an insufficiency of efficient pharmacological remedies. MiRNAs are a highly conserved class of non-coding small molecule RNAs, with a length of 20-24 nucleotides. Research has shown the presence of a number of differentially expressed miRNAs in the colonic tissue and peripheral blood of IBS patients. Meanwhile, miRNAs have a critical role in gene expression and the pathology of IBS as they act as significant mediators of post-transcriptional gene silencing. The investigation of miRNA molecular regulatory networks proves useful in examining the convoluted pathogenesis of IBS. This paper presents a review of recent literature on miRNAs associated with IBS, explains how miRNAs contribute to the development of IBS, and assesses the potential usefulness of miRNA analysis for diagnosing and treating IBS.

Tong-Xie-Yao-Fang alleviates diarrhea-predominant irritable bowel syndrome in rats via the GCN2/PERK-eIF2α-ATF4 signaling pathway

BACKGROUND

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disease. Tong-Xie-Yao-Fang (TXYF), the traditional Chinese herbal medicine prescription, is a classic and effective prescription for the treatment of IBS-D, but its mechanism of action is not fully clarified.

OBJECTIVE

To evaluate the efficacy of TXYF in the treatment of IBS-D and to explore its potential mechanism of action.

METHODS

Changes in the serum levels of 50 free amino acids were targeted for detection by high-performance liquid chromatography (HPLC), and the expression of glucose-regulated protein 78 (GRP78), general control nonderepressible 2 (GCN2), and endoplasmic reticulum-resident kinase (PERK) was detected by immunohistochemistry examinations in healthy volunteers and IBS-D patients. The IBS-D rat was constructed by the three-factor superposition method of neonatal maternal separation, 2,4,6-trinitrobenzene sulfonic acid enema, and chronic unpredictable stress stimulation. The treatment effect of TXYF on IBS-D rats was observed by recording the body weight, grasp force, fecal water content (FWC), and abdominal withdrawal reflex (AWR) of rats before and after treatment. The effects of GCN2/PERK-eukaryotic initiation factor-2 (eIF2α) -activating transcription Factor 4 (ATF4) pathway proteins and gene expression were analyzed by western blotting, reverse transcription-polymerase chain reaction (RT-qPCR), and immunohistochemistry evaluations.

RESULTS

Compared with healthy volunteers, IBS-D patients exhibited lower levels of cysteine, γ-aminoacetic acid (GABA), homoproline, and lysine, and immunohistochemistry showed strong activation of GRP78, a marker of endoplasmic reticulum stress. Differential expression of GCN2 and PERK proteins was detected in IBS-D patients and rat colons. In the IBS-D rats, TXYF improved the body weight and grasp force, reduced the FWC, and improved the AWR score. TXYF increased the levels of p-GCN2 and GCN2 and reduced the levels of GRP78, p-PERK, PERK, p-eIF2α, and eIF2α, thereby affecting the expression of the apoptosis-related transcription factors ATF4, CHOP, Caspase-3, and Bcl-2.

CONCLUSION

Our study showed that TXYF improved IBS-D by inhibiting apoptosis. The anti-apoptosis effects were potentially mediated by regulating the GCN2/PERK-eIF2a-ATF4 signaling pathway.

Efficacy of Tong-Xie-Yao-Fang granule and its impact on whole transcriptome profiling in diarrhea-predominant irritable bowel syndrome patients: study protocol for a randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is one kind of common functional bowel disease with obscure pathogenesis, and exploration about whole transcriptome profiling in IBS-D is still negligible. Conventional medications have limited effects, which makes focus shifted to traditional Chinese medicine (TCM). Tong-Xie-Yao-Fang, as a classic herbal formula in TCM, is pretty effective and safe for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), but the underlying therapeutic mechanism remains unknown. We aim to verify the efficacy and safety of TXYF granule (the formula particles mixed together) in IBS-D and elucidate the gene-level mechanism of IBS-D and therapeutic targets of TXYF granule based on whole transcriptome analysis.

METHODS/DESIGN

This is a randomized, double-blind, and placebo-controlled clinical trial consisting of 2 weeks of run-in period, 12 weeks of treatment period, and 8 weeks of follow-up period. We will enroll 120 participants with IBS-D, who will be randomly assigned to the TXYF granule group and the placebo group, and recruit additional 10 healthy individuals as controls for mechanistic outcome. The two groups respectively take TXYF granule or placebo orally for treatment. The primary outcome is the response rate of IBS-Symptom Severity Score (IBS-SSS). The secondary outcomes include adequate relief (AR), IBS-Quality of Life Questionnaire (IBS-QOL), and long-term efficacy. Mechanistic outcome is the whole transcriptome profiling of the intestinal mucosae from IBS participants before and after the treatment and healthy individuals.

DISCUSSION

This trial will prove the effectiveness and safety of TXYF granule with high-quality evidence and provide a penetrating and comprehensive perspective on the molecular mechanism of IBS-D by whole transcriptome analysis, which makes us pinpoint specific biomarkers of IBS-D and therapeutic targets of TXYF.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-IOR-1900021785 . Registered on 9 March 2019.

Inhibition of miRNA-29a regulates intestinal barrier function in diarrhea-predominant irritable bowel syndrome by upregulating ZO-1 and CLDN1

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common chronic functional gastrointestinal disorder. MicroRNAs (miRNAs) have been identified to be involved in different physiological and pathological processes. In this study, the role of miRNA-29a in the potential mechanism underlying the function of the intestinal mucosal barrier in IBS-D was analyzed. Human intestinal mucosal epithelia from patients with IBS-D (diagnosed as meeting the Rome IV criteria) and healthy volunteers were collected. An IBS-D mouse model was established via induction with trinitro-benzene-sulfonic acid (TNBS), and the mice were injected with miRNA-29a inhibitor. Using transmission electron microscopy (TEM), the epithelial ultrastructure of the human intestinal mucosa was examined. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, the expression level of miRNA-29a was assessed. ELISA was used to analyze the activity of D-lactate (D-LA) and diamine oxidase (DAO). Through immunohistochemistry, RT-qPCR and western blotting, the expression of tight junction protein ZO-1 (ZO-1) and claudin-1 (CLDN1) was examined. In the human intestinal mucosal epithelia from patients with IBS-D, miRNA-29a was upregulated, ZO-1 and CLDN1 were downregulated, and the junctional complex (JC) was faint and discontinuous. In the IBS-D mouse model, treatment with miRNA-29a inhibitor downregulated D-LA and DAO activity, and increased the expression of ZO-1 and CLDN1 in the intestinal mucosal epithelium. In conclusion, the present study revealed that miRNA-29a is involved in the pathogenesis of IBS-D, probably by downregulating ZO-1 and CLDN1 expression, suggesting that miRNA-29a is likely to be an important regulator of intestinal barrier function and could be a possible therapeutic target for IBS-D.

Clinical Effects and Safety of Tongxieyaofang on Diarrhea Predominant Irritable Bowel Syndrome: A Meta-Analysis of Randomized Trails

Background. Tongxieyaofang (TXYF), a prescription originated from traditional Chinese medicine (TCM), has been widely used on treating Diarrhea Predominant Irritable Bowel Syndrome (IBS-D). The purpose of this meta-analysis was to investigate whether TXYF was effective and safe for IBS-D. Methods. We searched seven electronic databases including CENTRAL, MEDLINE, PubMed, CNKI, VIP, CBM, and Wanfang Data up to 26 July 2017. Randomized controlled trails (RCTs) were eligible, regardless of blinding. Risk of bias of included trials was evaluated according to the Cochrane Handbook. Results. The total number of participants analyzed in the meta-analysis was 3062, of which 1556 received TXYF, while 1506 received ordinary treatment. The primary outcome was clinical effective rate. Compared with conventional medication which included probiotics, pinaverium bromide, trimebutine, and Oryzanol, TXYF significantly improved the clinical effective rate (n=37, OR: 4.61; 95% CI: 3.67–5.78; P < 0.00001) and decreased the adverse events (n=10, OR: 0.26; 95% CI: 0.08–0.86; P = 0.03). There was not significant association with the score of abdominal pain, defecating frequency, fecal property, and total symptom. Conclusions. We suggested a moderate recommendation for TXYF on IBS-D, due to the fact that the risk of bias of the finally included trails was not high. Considering that all identified studies were not of high qualities and large samples, further rigorously designed and large scale RCTs were necessary to improve the applicability of our study results.