miR-222 regulates cell growth, apoptosis, and autophagy of interstitial cells of Cajal isolated from slow transit constipation rats by targeting c-kit

Nanoemulsion based lipid nanoparticles for effective demethylcantharidin delivery to cure liver cancer

Demethylcantharidin (DEM) is a widely used antitumor drug; however, its poor tumor targeting and serious organotoxicity limit its application. The aim of this study was to develop a new drug delivery system for efficient delivery of DEM. Nanoemulsion based lipid nanoparticles containing demethylcantharidin (DNLNs) were prepared by loading nanoemulsions into lipid nanoparticles. The cells proliferation, apoptosis, cycle, and uptake were investigated by Cell counting kit-8 (CCK-8), flow cytometry, and in situ fluorescence assays, respectively. Then, we established the H22 tumor-bearing mouse model to evaluate the antitumor efficacy of DNLNs and further studied its organ toxicity and distribution. DNLNs significantly inhibited the proliferation and promoted apoptosis of H22 cells, and H22 cells could take up more DNLNs. Compared with DEM, DNLNs had certain tumor-targeting properties, and the tumor inhibition rate increased by 23.24%. Moreover, DNLNs can increase white blood cell count and reduce organ toxicity. This study paves the way for nanoemulsion-based lipid nanoparticle (NLNs)-efficient DEM delivery to treat liver cancer.

Integration of network pharmacology and experimental verifications reveals the Bian-Se-Tong mixture can alleviate constipation in STC rats by reducing apoptosis of Cajal cells via activating PI3K-Akt signaling pathway

Bian-Se-Tong mixture (BSTM) is an optimized formulation based on the classical prescription "Zhizhu pill", which is widely used in the clinical treatment of slow-transit constipation (STC). The potential molecular mechanism of BSTM therapy for STC was investigated by network pharmacology prediction combined with animal experiments. The active components of BSTM were screened via the TCMSP platform. The GeneCards, OMIM and DrugBank databases were used to search for STC targets. With the help of the Biogenet tool, a protein interaction network between drugs and disease targets was constructed, and the intersection network of the two was extracted to obtain the key targets of BSTM in the treatment of STC. GO and KEGG enrichment analyses of key targets were carried out with Metascape. Loperamide hydrochloride was used to establish an STC rat model, and the key targets and related pathways were preliminarily verified. The important signaling pathways included the PI3K-Akt, MAPK, IL-17, cAMP, and cell cycle signaling pathways. The experimental results showed that BSTM treatment increased the body weight of STC rats and increased the fecal particle number, fecal water content and intestinal carbon ink promotion rate within 24 h. Further pathological changes in the colon of the rats were also observed. In-depth mechanistic studies have shown that BSTM can significantly reduce the apoptosis of intestinal Cajal cells, downregulate the expression of Bax and c-Caspase 3, upregulate the expression of Bcl-2 and c-kit, and promote the phosphorylation of AKT. The results showed that BSTM can significantly relieve constipation in STC rats via a mechanism related to activating the PI3K-Akt signaling pathway and improving Cajal cell apoptosis.

Wei-Tong-Xin ameliorated cisplatin-induced mitophagy and apoptosis in gastric antral mucosa by activating the Nrf2/HO-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Tong-Xin (WTX) originated from the famous ancient Chinese formula "Wan Ying Yuan", recorded in the ancient Chinese medicine book "Zhong Zang Jing" by Hua Tuo. As "Jun" drugs, Dahuang and Muxiang have the effects of clearing heat and expelling fire, reducing food retention, regulating Qi and relieving pain. As "Chen" drug, Qianniuzi has the effect of assisting "Jun" drugs. Zhuyazao and Gancao, as "Zuo-Shi" drugs, can reduce toxicity and modulate the medicinal properties of other herbs.

AIM OF THE STUDY

The present study aimed to investigate the effect and mechanism of WTX on the oxidative stress of gastric antrum mucosa in mice with cisplatin (CIS)-induced dyspepsia.

MATERIALS

AND.

METHODS

A variety of experimental methods, including western blot, qRT-PCR, immunofluorescence and immunohistochemistry were performed in vivo and in vitro.

RESULTS

In vivo, WTX restored the number and function of interstitial cells of Cajal (ICCs), accompanied by the inhibition of lipid peroxidation. Moreover, WTX inhibited the activation of Parkin-dependent mitophagy and apoptosis. In vitro, WTX activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway and inactivated mitophagy in GES-1 cells. To explore the role of Nrf2 in WTX's improvement of CIS-induced cell damage, Nrf2 inhibitor ML385 was used in cell experiments. We found that ML385 counteracted the regulation of WTX on mitophagy and apoptosis. Finally, N-acetylcysteine (NAC), a reactive oxygen species (ROS) scavenger, was applied in our experiments, and the results suggested that WTX suppressed the CIS-induced apoptosis via mitochondrial pathway.

CONCLUSIONS

The above results, for the first time, indicated that WTX inhibited mitophagy and apoptosis of gastric antral mucosal cells induced by CIS through the Nrf2/HO-1 signaling pathway.

Effects of Banxia Xiexin Decoction on apoptosis of interstitial cells of cajal by regulation of MiR-451-5p: An in vivo and in vitro study

ETHNOPHARMACOLOGICAL RELEVANCE

Banxia Xiexin Decoction (BXD) is a traditional Chinese medical formula applied to gastrointestinal (GI) motility disorders. Previous studies showed that miR-451-5p was down-regulated in rats with GI motility disorders induced by gastric electrical dysrhythmia. Interstitial cells of cajal (ICCs) are pacemakers for GI motility, while loss of ICCs is responsible for GI motility disturbance. Thus, the underlying interaction mechanisms for BXD regulating ICCs apoptosis via miR-451-5p remain to be explored.

AIM OF THE STUDY

In this work, the main objectives were to examine the efficacy of BXD on ICCs via miR-451-5p both in GI motility disorders rats model and in vitro, as well as the potential contributions of SCF/c-kit signaling.

MATERIALS AND METHODS

Rats with gastric electrical dysrhythmia were established in male SD rats by using a single-day diet and a double fasting method (drinking diluted hydrochloric acid water during the period) for 4 weeks. The gastric slow wave (GSW) recording, RT-qPCR, and western blot were performed to examine the effects of BXD on ICCs apoptosis in rats with GED and miR-451-5p expression. In vitro assays included CCK-8, flow cytometry analysis, RT-qPCR, and western blot were applied to investigate the potential molecular mechanism of BXD on ICCs apoptosis via miR-451-5p.

RESULTS

BXD promoted gastric motility, reduced ICCs apoptosis, and elevated miR-451-5p in GED rats. In addition, miR-451-5p was significantly up-regulated in ICCs after BXD treatment compared with that in ICCs with miR-451-5p inhibitor transfection. Meanwhile, high miR-451-5p expression with either BXD treatment or miRNA mimics enhanced ICCs proliferation and inhibit apoptosis. Moreover, overexpression of miR-451-5p can reverse G0/G1 arrest in ICCs by BXD treatment. Further, SCF and c-kit protein levels were detected to demonstrate that modulation of miR-451-5p by BXD treatment was involved in this signaling.

CONCLUSIONS

Through this study, we demonstrated that BXD could promote ICCs proliferation and inhibit apoptosis via miR-451-5p and may involve the modulations of SCF/c-kit signaling, thus suggesting a new therapy basis for GI motility dysfunction from the perspective of modulation of ICCs apoptosis by targeting miR-451-5p.

Electroacupuncture Alleviates Functional Constipation in Mice by Activating Enteric Glial Cell Autophagy via PI3K/AKT/mTOR Signaling

OBJECTIVE

To investigate autophagy-related mechanisms of electroacupuncture (EA) action in improving gastrointestinal motility in mice with functional constipation (FC).

METHODS

According to a random number table, the Kunming mice were divided into the normal control, FC and EA groups in Experiment I. The autophagy inhibitor 3-methyladenine (3-MA) was used to observe whether it antagonized the effects of EA in Experiment II. An FC model was established by diphenoxylate gavage. Then the mice were treated with EA stimulation at Tianshu (ST 25) and Shangjuxu (ST 37) acupoints. The first black stool defecation time, the number, weight, and water content of 8-h feces, and intestinal transit rate were used to assess intestinal transit. Colonic tissues underwent histopathological assessment, and the expressions of autophagy markers microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1 were detected by immunohistochemical staining. The expressions of phosphoinositide 3-kinases (PI3K)-protein kinase B (AKT)-mammalian target of rapamycin (mTOR) signaling pathway members were investigated by Western blot and quantitative reverse transcription-polymerase chain reaction, respectively. The relationship between enteric glial cells (EGCs) and autophagy was observed by confocal immunofluorescence microscopy, localization analysis, and electron microscopy.

RESULTS

EA treatment shortened the first black stool defecation time, increased the number, weight, and water content of 8-h feces, and improved the intestinal transit rate in FC mice (P<0.01). In terms of a putative autophagy mechanism, EA treatment promoted the expressions of LC3 and Beclin-1 proteins in the colonic tissue of FC mice (P<0.05), with glial fibrillary acidic protein (GFAP) and LC3 significantly colocalized. Furthermore, EA promoted colonic autophagy in FC mice by inhibiting PI3K/AKT/mTOR signaling (P<0.05 or P<0.01). The positive effect of EA on intestinal motility in FC mice was blocked by 3-MA.

CONCLUSION

EA treatment can inhibit PI3K/AKT/mTOR signaling in the colonic tissues of FC mice, thereby promoting EGCs autophagy to improve intestinal motility.

Effects of Emodin on Protein Expression Related to Autophagy of Interstitial Cells of Cajal in Diabetic Rats

This work aims to investigate the effects and mechanism of emodin in treating diabetic gastroenteropathy and colonic dysmotility in STZ + HS/HF diet induced diabetic gastroenteropathy rats. Diabetic colonic dysmotility model was established by high-fat/high-glucose (HS/HF) feeding combined with streptozotocin (STZ). Emodin was divided into high, medium and low dose groups. After eight weeks of intervention, fasting blood glucose (FBG) and body weight were measured. Gastrointestinal transmission time was evaluated. Serum vasoactive intestinal peptide (VIP) and substance P (SP) were detected. Colonic protein expression of selective autophagy adaptor proteins p62 and beclin1 were detected by immunohistochemistry. Colonic protein expression of beclin1, autophagy related gene 5 (Atg5), C-kit and p62 were detected by Western blot. After treating with emodin, gastrointestinal transmission rate was improved. The expression of serum SP was increased and serum VIP was decreased. Colonic c-kit and p62 were up-regulated. The expressions of beclin1 and Atg5 were down-regulated. Emodin can improve colonic dysmotility and promote the recovery of colonic motility and intestinal defecation in diabetic rats. Its mechanism may involved with up-regulating the expression of C-kit and P62, down-regulating the expression of Beclin1 and Atg5 in colon, which are associated with colon over-autophagy of Cajal interstitial cell (ICC).

Latilactobacillus sakei Furu2019 and stachyose as probiotics, prebiotics, and synbiotics alleviate constipation in mice

Introduction

Slow transit constipation (STC) is a common disorder in the digestive system. This study aimed to evaluate the effects of stachyose (ST) and Latilactobacillus sakei Furu 2019 (L. sakei) alone or combined on diphenoxylate-induced constipation and explore the underlying mechanisms using a mouse model.

Methods

ICR mice were randomly divided into five groups. The normal and constipation model groups were intragastrically administrated with PBS. The ST, L. sakei, and synbiotic groups were intragastrically administrated with ST (1.5 g/kg body weight), alive L. sakei (3 × 10⁹ CFU/mouse), or ST + L. sakei (1.5 g/kg plus 3 × 10⁹ CFU/mouse), respectively. After 21 days of intervention, all mice except the normal mice were intragastrically administrated with diphenoxylate (10 mg/kg body weight). Defecation indexes, constipation-related intestinal factors, serum neurotransmitters, hormone levels, short-chain fatty acids (SCFAs), and intestinal microbiota were measured.

Results

Our results showed that three interventions with ST, L. sakei, and synbiotic combination (ST + L. sakei) all alleviated constipation, and synbiotic intervention was superior to ST or L. sakei alone in some defecation indicators. The RT-PCR and immunohistochemical experiment showed that all three interventions relieved constipation by affecting aquaporins (AQP4 and AQP8), interstitial cells of Cajal (SCF and c-Kit), glial cell-derived neurotrophic factor (GDNF), and Nitric Oxide Synthase (NOS). The three interventions exhibited a different ability to increase the serum excitatory neurotransmitters and hormones (5-hydroxytryptamine, substance P, motilin), and reduce the serum inhibitory neurotransmitters (vasoactive intestinal peptide, endothelin). The result of 16S rDNA sequencing of feces showed that synbiotic intervention significantly increased the relative abundance of beneficial bacteria such as Akkermansia, and regulated the gut microbes of STC mice. In conclusion, oral administration of ST or L. sakei alone or combined are all effective to relieve constipation and the symbiotic use may have a promising preventive effect on STC.

METTL3 contributes to slow transit constipation by regulating miR-30b-5p/PIK3R2/Akt/mTOR signaling cascade through DGCR8

BACKGROUND

N6-methyladenosine (m6A) is the most prevalent methylation modification of eukaryotic RNA, and methyltransferase-like 3 (METTL3) plays a vital role in multiple cell functions. This study aimed to investigate the role of m6A methylase METTL3 in slow transit constipation (STC).

MATERIAL AND METHOD

The expression of METTL3 and DGCR8 was measured in STC tissues and glutamic acid-induced interstitial cells of Cajal (ICCs). The effects of METTL3, miR-30b-5p, and DGCR8 on the biological characteristics of ICCs were investigated on the basis of loss-of-function analyses. Luciferase reporter assay was used to identify the direct binding sites of miR-30b-5p with PIK3R2.

RESULTS

The results showed that the METTL3, DGCR8, miR-30b-5p, and the methylation level of m6A were significantly increased in STC tissues and glutamic acid-induced ICCs. Silencing of METTL3 and miR-30b-5p inhibited apoptosis, autophagy, and pyroptosis of glutamic acid-induced ICCs. Moreover, overexpression of miR-30b-5p reversed the cytoprotection of METTL3 knockdown in glutamic acid-induced ICCs. Besides, DGCR8 knockdown could facilitate cell growth and decrease apoptotic glutamic acid-induced ICCs. Mechanically, we illustrated that METTL3 in glutamic acid-induced ICCs significantly accelerated the maturation of pri-miR-30b-5p by m6A methylation modification, resulting in the reduction of PIK3R2, which results in the inhibition of PI3K/Akt/mTOR pathway and ultimately leads to the cell death of STC.

CONCLUSIONS

Collectively, these data demonstrated that METTL3 promoted the apoptosis, autophagy, and pyroptosis of glutamic acid-induced ICCs by interacting with the DGCR8 and successively modulating the miR-30b-5p/PIK3R2 axis in an m6A-dependent manner, and METTL3 may be a potential therapeutic target for STC.

Electroacupuncture Improves Intestinal Motility through Exosomal miR-34c-5p Targeting SCF/c-Kit Signaling Pathway in Slow Transit Constipation Model Rats

Background. The pathogenesis of slow transit constipation (STC) is associated with exosomal miR-34c-5p. Electroacupuncture (EA) improves gastrointestinal motility in gastrointestinal disorders, especially STC. Our study aimed to explore the mechanism by which EA improves intestinal motility by modulating the release of exosomes and the transmission of exosomal miR-34c-5p. Methods. Fifty rats were randomly divided into five groups. STC model rats were induced, and GW4869, the exosome release inhibitor, was used to inhibit the release of exosome. The serum exosomes were authenticated under a transmission electron microscope and nanoparticle tracking analysis. RT-qPCR detected the expression of miR-34c-5p in serum exosomes and colonic tissues. The fecal number in 24 hours, Bristol scores, and intestinal transit rates were used to assess intestinal motility. Subsequently, hematoxylin and eosin (H&E) staining was used to examine the colonic mucosal histology. Finally, the expression of stem cell factor (SCF) and receptor tyrosine kinase (c-Kit) protein was measured using immunohistochemistry staining. Results. We found that EA upregulated exosomal miR-34c-5p in serum and downregulated miR-34c-5p in colonic tissues ( $P<0.01$ ). EA improved fecal numbers in 24 hours, Bristol scores, and intestinal transit rates in STC rats ( $P<0.01$ ). EA recovered the colonic histological structure and enhanced the expression of SCF and c-Kit protein ( $P<0.01$ ). The therapeutic effect of EA was attenuated after inhibiting the release of the exosome. Conclusion. Our results indicated that EA improves intestinal motility in STC rats by transporting of exosomal miR-34c-5p targeting the SCF/c-Kit signaling pathway.

Mechanistic Prediction of Chinese Herb Compound (Zhi Zhu Ma Ren Pill) in the Treatment of Constipation Using Network Pharmacology and Molecular Docking

Background: Constipation is one of the most prevalent chronic gastrointestinal diseases. Notably, previous studies have demonstrated that Chinese herbal compounds may exert effects on constipation. The present study aimed to predict the mechanisms underlying the effects of Zhi Zhu Ma Ren Pill (ZZMRP), which includes Aurantii Fructus Immaturus, Atractylodis Macrocephalae Rhizoma, Fructus Cannabis, Paeonia lactiflora and Radix Asteris in the treatment of constipation, using network pharmacology and molecular docking. Methods: The components and target information of ZZMRP were accessed using the Traditional Chinese Medicine Systems Pharmacology database and analysis platform, and the associated targets of constipation were obtained from the GeneCards, Disgenet, Online Mendelian Inheritance in Man, DrugBANK and Therapeutic Target Database databases. The major targets were subsequently selected using a Venn diagram and network topology analysis, which was followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was performed to authenticate the binding activity between active components and core targets. Results: A total of 44 active components, 249 targets of ZZMRP and 1501 targets associated with constipation were acquired. A total of 122 intersection targets were discovered between ZZMRP and constipation. Subsequently, 18 key targets were authenticated, including tumor protein 53, RAC-alpha serine/threonine-protein kinase, JUN and caspase-3. GO and KEGG pathway enrichment analysis indicated that mitogen-activated protein kinase, tumor necrosis factor, and phosphoinositide 3-kinase/protein kinase B signaling pathways may be involved in the treatment of constipation using ZZMRP. Molecular docking suggested that quercetin, kaempferol, and luteolin exhibited high binding affinities with several of the primary targets. Conclusions: The active components, core targets, and signaling pathways of ZZMRP in the treatment of constipation were predicted, which may be applicable to the development of treatments for constipation and application of ZZMRP.

Characterization of Circular RNA Expression Profiles in Colon Specimens of Patients with Slow Transit Constipation

Background

Slow transit constipation (STC) is a clinical syndrome characterized by a decreased urge to defecate and delayed colonic transit. Circular RNAs (circRNAs) are a recently discovered class of regulatory RNAs that have emerged as critical biomarkers and regulators of various diseases. However, the expression profiles and mechanisms underlying circRNA regulation in human STC tissues have not been explored.

Methods

High-throughput RNA sequencing technology was used to compare the differences in circRNA expression profiles in colon samples taken from patients with STC or controls. Bioinformatics analyses were performed on the host genes of the differentially expressed circRNAs (DE-circRNAs), a competing endogenous RNA network was constructed, and the expression levels of some DE-circRNAs were verified using quantitative real-time polymerase chain reactions (qRT-PCR).

Results

There were 190 DE-circRNAs identified in the STC group. Bioinformatics analysis predicted that the DE-circRNAs were enriched in the relaxation of smooth muscle, actin binding, actin cytoskeleton organization, dilated cardiomyopathy, and cardiac muscle contraction. These results suggest that muscle diseases may be related to the pathogenesis of STC. The expression levels of the 12 most differentially expressed circRNAs were verified using qRT-PCR. In addition, circRNA–microRNA–mRNA regulatory networks were constructed using the 8 most significant circRNAs. Some mRNAs predicted to be closely related to smooth muscle function were found in these networks.

Conclusions

This study provides a helpful blueprint for researchers to select candidate circRNAs for further study of the pathogenesis of STC and screen potential biomarkers or targets for use in the diagnosis and treatment of STC.

Based on Network Pharmacology and Gut Microbiota Analysis to Investigate the Mechanism of the Laxative Effect of Pterostilbene on Loperamide-Induced Slow Transit Constipation in Mice

Background: Pterostilbene (PTE) is a natural polyphenol compound that has been proven to improve intestinal inflammation, but its laxative effect on slow transit constipation (STC) has never been studied. This study aims to investigate the laxative effect of PTE on loperamide (LOP)-induced STC mice and its influence on intestinal microbes through a combination of network pharmacological analysis and experimental verification.

Material and Methods: PTE was used to treat LOP-exposed mice, and the laxative effect of PTE was evaluated by the total intestinal transit time and stool parameters. The apoptosis of Cajal interstitial cells (ICCs) was detected by immunofluorescence. The mechanism of PTE’s laxative effect was predicted by network pharmacology analysis. We used western blot technology to verify the predicted hub genes and pathways. Malondialdehyde (MDA) and GSH-Px were tested to reflect oxidative stress levels and the changes of gut microbiota were detected by 16S rDNA high-throughput sequencing.

Results: PTE treatment could significantly improve the intestinal motility disorder caused by LOP. Apoptosis of ICCs increased in the STC group, but decreased significantly in the PTE intervention group. Through network pharmacological analysis, PTE might reduce the apoptosis of ICCs by enhancing PI3K/AKT and Nrf2/HO-1 signaling, and improve constipation caused by LOP. In colon tissues, PTE improved the Nrf2/HO-1 pathway and upregulated the phosphorylation of AKT. The level of MDA increased and GSH-Px decreased in the STC group, while the level of oxidative stress was significantly reduced in the PTE treatment groups. PTE also promoted the secretion of intestinal hormone and restored the microbial diversity caused by LOP.

Conclusion: Pterostilbene ameliorated the intestinal motility disorder induced by LOP, this effect might be achieved by inhibiting oxidative stress-induced apoptosis of ICCs through the PI3K/AKT/Nrf2 signaling pathway.

Current Treatment Options and Therapeutic Insights for Gastrointestinal Dysmotility and Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) have been re-named as disorders of gut-brain interactions. These conditions are not only common in clinical practice, but also in the community. In reference to the Rome IV criteria, the most common FGIDs, include functional dyspepsia (FD) and irritable bowel syndrome (IBS). Additionally, there is substantial overlap of these disorders and other specific gastrointestinal motility disorders, such as gastroparesis. These disorders are heterogeneous and are intertwined with several proposed pathophysiological mechanisms, such as altered gut motility, intestinal barrier dysfunction, gut immune dysfunction, visceral hypersensitivity, altered GI secretion, presence and degree of bile acid malabsorption, microbial dysbiosis, and alterations to the gut-brain axis. The treatment options currently available include lifestyle modifications, dietary and gut microbiota manipulation interventions including fecal microbiota transplantation, prokinetics, antispasmodics, laxatives, and centrally and peripherally acting neuromodulators. However, treatment that targets the pathophysiological mechanisms underlying the symptoms are scanty. Pharmacological agents that are developed based on the cellular and molecular mechanisms underlying pathologies of these disorders might provide the best avenue for future pharmaceutical development. The currently available therapies lack long-term effectiveness and safety for their use to treat motility disorders and FGIDs. Furthermore, the fundamental challenges in treating these disorders should be defined; for instance, 1. Cause and effect cannot be disentangled between symptoms and pathophysiological mechanisms due to current therapies that entail the off-label use of medications to treat symptoms. 2. Despite the knowledge that the microbiota in our gut plays an essential part in maintaining gut health, their exact functions in gut homeostasis are still unclear. What constitutes a healthy microbiome and further, the precise definition of gut microbial dysbiosis is lacking. More comprehensive, large-scale, and longitudinal studies utilizing multi-omics data are needed to dissect the exact contribution of gut microbial alterations in disease pathogenesis. Accordingly, we review the current treatment options, clinical insight on pathophysiology, therapeutic modalities, current challenges, and therapeutic clues for the clinical care and management of functional dyspepsia, gastroparesis, irritable bowel syndrome, functional constipation, and functional diarrhea.

Role of microRNAs in Disorders of Gut-Brain Interactions: Clinical Insights and Therapeutic Alternatives

Disorders of gut–brain interactions (DGBIs) are heterogeneous in nature and intertwine with diverse pathophysiological mechanisms. Regular functioning of the gut requires complex coordinated interplay between a variety of gastrointestinal (GI) cell types and their functions are regulated by multiple mechanisms at the transcriptional, post-transcriptional, translational, and post-translational levels. MicroRNAs (miRNAs) are small non-coding RNA molecules that post-transcriptionally regulate gene expression by binding to specific mRNA targets to repress their translation and/or promote the target mRNA degradation. Dysregulation of miRNAs might impair gut physiological functions leading to DGBIs and gut motility disorders. Studies have shown miRNAs regulate gut functions such as visceral sensation, gut immune response, GI barrier function, enteric neuronal development, and GI motility. These biological processes are highly relevant to the gut where neuroimmune interactions are key contributors in controlling gut homeostasis and functional defects lead to DGBIs. Although extensive research has explored the pathophysiology of DGBIs, further research is warranted to bolster the molecular mechanisms behind these disorders. The therapeutic targeting of miRNAs represents an attractive approach for the treatment of DGBIs because they offer new insights into disease mechanisms and have great potential to be used in the clinic as diagnostic markers and therapeutic targets. Here, we review recent advances regarding the regulation of miRNAs in GI pacemaking cells, immune cells, and enteric neurons modulating pathophysiological mechanisms of DGBIs. This review aims to assess the impacts of miRNAs on the pathophysiological mechanisms of DGBIs, including GI dysmotility, impaired intestinal barrier function, gut immune dysfunction, and visceral hypersensitivity. We also summarize the therapeutic alternatives for gut microbial dysbiosis in DGBIs, highlighting the clinical insights and areas for further exploration. We further discuss the challenges in miRNA therapeutics and promising emerging approaches.

Gut microbiota dysbiosis in functional gastrointestinal disorders: Underpinning the symptoms and pathophysiology

Functional gastrointestinal disorders (FGIDs), currently known as disorders of gut-brain interaction, are emerging microbiota-gut-brain abnormalities that are prevalent worldwide. The pathogenesis of FGIDs is heterogeneous and is intertwined with gut microbiota and its derived molecule-modulated mechanisms, including gut dysmotility, visceral hypersensitivity, gut immune abnormalities, abnormal secretion, and impaired barrier function. There has been phenomenal progress in understanding the role of gut microbiota in FGIDs by underpinning the species alternations between healthy and pathological conditions such as FGIDs. However, the precise gut microbiota-directed cellular and molecular pathogeneses of FGIDs are yet enigmatic. Determining the mechanistic link between the gut microbiota and gastrointestinal (GI) diseases has been difficult due to (i) the lack of robust animal models imitating the various aspects of human FGID pathophysiology; (ii) the absence of longitudinal human and/or animal studies to unveil the interaction of the gut microbiota with FGID-relevant pathogenesis; (iii) uncertainty about connections between human and animal studies; and (iv) insufficient data supporting a holistic view of disease-specific pathophysiological changes in FGID patients. These unidentified gaps open possibilities to explore pathological mechanisms directed through gut microbiota dysbiosis in FGIDs. The current treatment options for dysbiotic gut microbiota are limited; dietary interventions, antibiotics, probiotics, and fecal microbiota transplantation are the front-line clinical options. Here, we review the contribution of gut microbiota and its derived molecules in gut homeostasis and explore the possible pathophysiological mechanisms involved in FGIDs leading to potential therapeutics options.