Investigation of autophagy and differentiation of myenteric interstitial cells of Cajal in the pathogenesis of gastric motility disorders in rats with functional dyspepsia

A bibliometric analysis of interstitial cells of Cajal research

Objective

The significance of interstitial cells of Cajal (ICC) in the gastrointestinal tract has garnered increasing attention. In recent years, approximately 80 articles on ICC have been published annually in various journals. However, no bibliometric study has specifically focused on the literature related to ICC. Therefore, we conducted a comprehensive bibliometric analysis of ICC to reveal dynamic scientific developments, assisting researchers in exploring hotspots and emerging trends while gaining a global perspective.

Methods

We conducted a literature search in the Web of Science Core Collection (WoSCC) from January 1, 2013, to December 31, 2023, to identify relevant literature on ICC. We employed bibliometric software, namely VOSviewer and CiteSpace, to analyze various aspects including annual publication output, collaborations, research hotspots, current status, and development trends in this domain.

Results

A total of 891 English papers were published in 359 journals by 928 institutions from 57 countries/regions. According to the keyword analysis of the literature, researchers mainly focused on "c-Kit," "expression," "smooth muscle," and "nitric oxide" related to ICC over the past 11 years. However, with "SIP syncytium," "ANO1," "enteric neurons," "gastrointestinal stromal tumors (GIST)," and "functional dyspepsia (FD)," there has been a growing interest in the relationship between ANO1, SIP syncytium, and ICC, as well as the role of ICC in the treatment of GIST and FD.

Conclusion

Bibliometric analysis has revealed the current status of ICC research. The association between ANO1, SIP syncytium, enteric neurons and ICC, as well as the role of ICC in the treatment of GIST versus FD has become the focus of current research. However, further research and collaboration on a global scale are still needed. Our analysis is particularly valuable to researchers in gastroenterology, oncology, and cell biology, providing insights that can guide future research directions.

Chaihu Shugan Powder inhibits interstitial cells of cajal mitophagy through USP30 in the treatment of functional dyspepsia

ETHNOPHARMACOLOGICAL RELEVANCE

Chaihu Shugan Powder (CHSGP) has significant clinical efficacy in the treatment of functional dyspepsia (FD), but the specific mechanism requires further study.

AIM OF STUDY

The aim of this study was to investigate the therapeutic effect of CHSGP on FD rats and the underlying mechanism of the effect on interstitial cells of cajal (ICC) mitophagy.

MATERIALS AND METHODS

The tail-clamping stimulation method was utilized to establish an FD rat model in vivo. Gastric emptying rate and small intestinal propulsion rate test, H&E staining, and Immunohistochemistry were conducted to evaluate the therapeutic effects of CHSGP on FD rats. In vitro, the regulatory effect of CHSGP on CCCP-mediated ICC mitophagy was further investigated by CCK8, Transmission electron microscope, immunofluorescence co-staining, Quantitative polymerase chain reaction and Western blot to reveal the potential mechanisms of CHSGP inhibited ICC mitophagy.

RESULTS

Animal experiments provided evidence that CHSGP promoted gastric motility, increased ICC numbers, reduced Parkin expression, and elevated USP30 expression in FD rats. In vitro, further mechanism research demonstrated that CHSGP decreased LC3Ⅱ/LC3Ⅰ、PINK1、Parkin、PHB2 protein expression and increased USP30 protein expression. Furthermore, CHSGP increased Mfn2 protein expression by suppressing activation of the PINK1/Parkin pathway when USP30 is knocked down, consequently reducing CCCP-induced ICC mitophagy.

CONCLUSIONS

These results suggest that CHSGP may treat FD against CCCP-induced ICC mitophagy by the up-regulation of via PINK1/Parkin pathway.

Effects of natural products on functional constipation: analysis of active ingredient and mechanism

Constipation is a prevalent clinical ailment of the gastrointestinal system, yet its pathogenesis remains ambiguous. Despite the availability of numerous treatment modalities, they are insufficient in resolving the issue for patients. This work conducted a comprehensive review of the existing literature pertaining to the utilization of natural products for the treatment of constipation, with a focus on the efficacy of natural products in treating constipation, and to provide a comprehensive summary of their underlying mechanisms of action. Upon conducting a thorough review of the extant literature, we found that natural products can effectively treat constipation as modern synthetic drugs and compounded drugs with acetylcholinesterase (AChE) effects, rich in fiber and mucus, and the effects of increasing the tension of the ileum and gastrointestinal tract muscle, mediating signaling pathways, cytokine, excitability of the smooth muscle of the gastrointestinal tract, and regulating the homeostasis of intestinal flora. However, there is a wide variety of natural products, and there are still relatively few studies; the composition of natural products is complex, and the mechanism of action of natural products cannot be clarified. In the future, we need to further improve the detailed mechanism of natural products for the treatment of constipation.

Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases

Autophagy is a cellular catabolic process characterized by the formation of double-membrane autophagosomes. Transmission electron microscopy is the most rigorous method to clearly visualize autophagic engulfment and degradation. A large number of studies have shown that autophagy is closely related to the digestion, secretion, and regeneration of gastrointestinal (GI) cells. However, the role of autophagy in GI diseases remains controversial. This article focuses on the morphological and biochemical characteristics of autophagy in GI diseases, in order to provide new ideas for their diagnosis and treatment.

Total Flavonoids of Aurantii Fructus Immaturus Regulate miR-5100 to Improve Constipation by Targeting Fzd2 to Alleviate Calcium Balance and Autophagy in Interstitial Cells of Cajal

Aurantii Fructus Immaturus total flavonoids (AFIF) is the main effective fraction extracted from AFI, which has a good effect on promoting gastrointestinal motility. This study aimed to investigate AFIF which regulates miR-5100 to improve constipation symptoms in mice by targeting Frizzled-2 (Fzd2) to alleviate interstitial cells of Cajal (ICCs) calcium ion balance and autophagy apoptosis. The constipated mouse model was induced by an antibiotic suspension, and then treated with AFIF. RNA-seq sequencing, luciferase assay, immunofluorescence staining, transmission electron microscopy, ELISA, flow cytometry, quantitative polymerase chain reaction (PCR), and Western blot were applied in this study. The results showed that AFIF improved constipation symptoms in antibiotic-induced constipated mice, and decreased the autophagy-related protein Beclin1 levels and the LC3-II/I ratio in ICCs. miR-5100 and its target gene Fzd2 were screened as key miRNAs and regulator associated with autophagy. Downregulation of miR-5100 caused increased expression of Fzd2, decreased proliferation activity of ICCs, increased apoptotic cells, and enhanced calcium ion release and autophagy signals. After AFIF treatment, miR-5100 expression was upregulated and Fzd2 was downregulated, while autophagy-related protein levels and calcium ion concentration decreased. Furthermore, AFIF increased the levels of SP, 5-HT, and VIP, and increased the expression of PGP9.5, Sy, and Cx43, which alleviated constipation by improving the integrity of the enteric nervous system network. In conclusion, AFIF could attenuate constipation symptoms by upregulating the expression of miR-5100 and targeting inhibition of Fzd2, alleviating calcium overload and autophagic death of ICCs, regulating the content of neurotransmitters, and enhancing the integrity of the enteric nervous system network.

Effects of Saikosaponin D on Apoptosis, Autophagy, and Morphological Structure of Intestinal Cells of Cajal with Functional Dyspepsia

OBJECTIVE

Functional dyspepsia (FD) is one of the most common gastrointestinal diseases, with a global prevalence of 10%-30%. However, the specific pathogenesis of FD has not yet been determined. As such, the aim of this study was to investigate the effects of saikosaponin D (SSD) administration on the apoptosis, autophagy, and morphological structure of the intestinal cells of Cajal (ICCs) in FD.

METHODS

A rat model of FD was constructed by stimulating the rat tail with a sponge clamp at one-third of the distal tail length. An autophagy model was constructed for ICCs using glutamate. The apoptosis rate in each group of cells was determined using flow cytometry. The expressions of ghrelin and substance P (SP) were detected using ELISA.

RESULTS

The body weight and food intake of male and female rats in the SSD group were consistently higher than those in the model group. The SSD group showed substantial improvement compared with the model group, with no inflammatory cell infiltration and normal gastric mucosal structures. After intervention with SSD, the ultrastructure of the ICCs considerably improved and was clear. Compared with the model group, the expressions of LC3 I/II, ghrelin, and SP proteins in the SSD group were significantly upregulated, and the apoptosis rate was significantly reduced.

CONCLUSION

The administration of SSD improved ICC morphology and structure, inhibited excessive autophagy, and improved FD, a gastrointestinal motility disorder, by regulating ghrelin and SP levels.

Chaihu Shugan San promotes gastric motility in rats with functional dyspepsia by regulating Drp-1-mediated ICC mitophagy

CONTEXT

Chaihu Shugan San (CHSGS) was effective in the treatment of functional dyspepsia (FD).

OBJECTIVE

To investigate the mechanism of CHSGS in FD through dynamin-related protein 1 (Drp-1)-mediated interstitial cells of cajal (ICC) mitophagy.

MATERIALS AND METHODS

Forty Sprague-Dawley (SD) rats were randomly divided into control, model, mdivi-1, mdivi-1 + CHSGS and CHSGS groups. Tail-clamping stimulation was used to establish the FD model. Mdivi-1 + CHSGS and CHSGS groups were given CHSGS aqueous solution (4.8 g/kg) by gavage twice a day. Mdivi-1 (25 mg/kg) was injected intraperitoneally once every other week for 4 w. Mitochondrial damage was observed by corresponding kits and related protein expressions were assessed by Immunofluorescence and (or) Western Blot.

RESULTS

Compared with the mean value of the control group, superoxide dismutase (SOD) and citrate synthase (CS) in the model group were decreased by 11% and 35%; malondialdehyde (MDA) and reactive oxygen species (ROS) were increased by 1.2- and 2.8-times; ckit fluorescence and protein expressions were decreased by 85% and 51%, co-localization expression of LC3 and voltage dependent anion channel 1 (VDAC1), Drp-1 and translocase of the outer mitochondrial membrane 20 (Tom20) were increased by 10.1- and 5.4-times; protein expressions of Drp-1, Beclin-1, and LC3 were increased by 0.5-, 1.4-, and 2.5-times whereas p62 was decreased by 43%. After mdivi-1 and (or) CHSGS intervention, the above situation has been improved.

DISCUSSION AND CONCLUSION

CHSGS could improve mitochondrial damage and promote gastric motility in FD rats by regulating Drp-1-mediated ICC mitophagy.

Systems biology strategy through integrating metabolomics and network pharmacology to reveal the mechanisms of Xiaopi Hewei Capsule improves functional dyspepsia

Functional dyspepsia (FD) is one of the more common functional disorders, with a prevalence of 20-25 %. It seriously affects the quality life of patients. Xiaopi Hewei Capsule (XPHC) is a classic formula originated from the Chinese Miao minority. Clinical studies have demonstrated that XPHC can effectively alleviate the symptoms of FD, but the molecular mechanism has not been elucidated. The purpose of this work is to investigate the mechanism of XPHC on FD by integrating metabolomics and network pharmacology. The mice models of FD were established, and gastric emptying rate, small intestine propulsion rate, serum level of motilin and gastrin were evaluate to study the interventional effect of XPHC on FD. Next, a metabolomics strategy has been developed to screen differential metabolites and related metabolic pathways induced by XPHC. Then, prediction of active compounds, targets and pathways of XPHC in treating FD were carried out by commonly used network pharmacological method. Finally, two parts of the results were integrated to investigate therapeutic mechanism of XPHC on FD, which were preliminary validated based on molecular docking. Thus, twenty representative different metabolites and thirteen related pathways of XPHC in treating FD were identified. Most of these metabolites were restored using modulation after XPHC treatment. The results of the network pharmacology analysis showed ten crucial compounds and nine hub genes related to the treatment of FD with XPHC. The further integrated analysis focused on four key targets, such as albumin (ALB), epidermal growth factor receptor (EGFR), tumor necrosis factor (TNF) and roto-oncogene tyrosine-protein kinase Src (SRC), and three representative biomarkers such as citric acid, L-leucine and eicosapentaenoic acid. Furthermore, molecular docking results showed that ten bioactive compounds from XPHC have good binding interactions with the four key genes. The functional enrichment analysis indicated that the potential mechanism of XPHC in treating FD was mainly associated with energy metabolism, amino acid metabolism, lipid metabolism, inflammatory reactions and mucosal repair. Our work confirms that network pharmacology-integrated metabolomics strategyis a powerful means to reveal the therapeutic mechanisms of XPHC improves FD, which contribute its further scientific research.

Network pharmacology and experimental studies for deciphering the molecular targets and mechanisms of Chaihu Shugan powder in the treatment of functional dyspepsia

BACKGROUND

Chaihu Shugan powder (CSP) is a prevalent prescription product used in the treatment functional dyspepsia (FD) in China. However, the underlying pharmacological mechanisms involved in the treatment of FD remain unclear.

OBJECTIVE

To explore the key components of CSP and their molecular targets and mechanisms in the treatment of FD.

METHODS

Active compounds for CSP were identified from the TCMSP and SymMap databases, and the relevant targets were predicted. FD-related targets were obtained from the CTD database. In addition, using the protein-protein interactions (PPI) analysis, the common targets were obtained. Furthermore, the compound-target networks were created with Cytoscape. Finally, molecular docking was performed to identify the core targets and validate them experimentally.

RESULTS

In total, 78 active compounds and 671 related targets of CSP were obtained. PPI network analysis identified 15 key FD-related compound targets. Molecular docking revealed that sitosterol and hyndarin exhibited good binding activities with AKT1 and IL6, respectively. Animal experiments have shown that CSP effectively increased the protein levels of AKT1 and reduced the serum levels of IL-6 in FD rats.

CONCLUSION

This study provides a theoretical evidence for the analysis of the molecular targets and mechanisms of the action of CSP in FD.

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.

Research progress of treatment of functional dyspepsia with traditional Chinese medicine compound based on cell signal pathway

Functional dyspepsia (FD) is the most common clinical gastrointestinal disease, with complex and prolonged clinical symptoms. The prevalence of FD is increasing year by year, seriously affecting the quality of life of patients. The main causes of FD are related to abnormal gastrointestinal dynamics, increased visceral sensitivity, Helicobacter pylori (HP) infection, intestinal flora disturbance and psychological factors. A review of the relevant literature reveals that the mechanisms of traditional Chinese medicine (TCM) in the treatment of FD mainly involve the following pathways:5-HT signal pathway, AMPK signal pathway,C-kit signal pathway, CRF signal pathway, PERK signal pathway,NF-κB signal pathway. Based on a holistic concept, TCM promotes gastrointestinal motility, regulates visceral sensitivity and alleviates gastrointestinal inflammation through multiple signal pathways, reflecting the advantages of multi-level, multi-pathway and multi-targeted treatment of FD.

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.

Investigation of the improving effect of raw and charred hawthorn on functional dyspepsia based on interstitial cells of Cajal

Background

Raw hawthorn (RH) is a traditional Chinese medicine commonly used to treat indigestion. Charred hawthorn (CH) is obtained from RH by charring. It is reported that the effect of CH treatment on dyspepsia is stronger than RH. However, this has not been fully proven. The purpose of this study was to compare the effects of RH and CH on functional dyspepsia (FD) model rats. And contribute to the development of dietary therapy for dyspepsia.

Methods

SPF-grade male SD rats were divided into 5 groups: the control group, the model group, the Mos group, the RH group, and the CH group. The FD rat model was established by using the methods of water restriction, fasting, tilting cage restraint, day and night upside down, swimming, and tail damping. The body weight of rats in each group was recorded. And the gastric emptying rate, intestinal propulsive rate, and the levels of motilin (MTL), gastrin (GAS), and 5-HT in serum were compared in each group. The expression of C-kit in the stomach and small intestine of each group was compared by immunofluorescence and PCR.

Results

RH and CH could increase weight, improve the gastric emptying rate and intestinal propulsive rate, and promote the secretion of motilin (MTL), gastrin (GAS), and 5-HT in the serum of FD rats. RH and CH can upregulate the expression of the characteristic protein c-kit of ICC in the stomach and small intestine of FD model rats, and the effect of CH is stronger than RH.

Conclusion

RH and CH may increase the number of interstitial cells of Cajal (ICC) in the gastrointestinal tract by upregulating c-kit expression, thus improving gastrointestinal motility in FD model rats. And compared with RH, CH has certain advantages.

Xiangsha Liujunzi Decoction improves gastrointestinal motility in functional dyspepsia with spleen deficiency syndrome by restoring mitochondrial quality control homeostasis

BACKGROUND

Xiang Sha Liu Junzi decoction (XSLJZD) is a famous traditional Chinese medicinal prescription for the treatment of functional dyspepsia (FD) in spleen deficiency. However, its therapeutic mechanism has not been fully clarified.

PURPOSE

The present study aimed to determine the role of mitochondrial quality control (MQC)-mediated gastrointestinal motility disorder in FD treated with XSLJZD by using spleen-deficient FD rats and gastrointestinal smooth muscle cells (GSMCs).

METHODS

In vivo, an FD with spleen deficiency syndrome model was established by gastric perfusion with iodoacetamide solution combined with the modified multiple platform method (MMPM), followed by intragastric gavage with XSLJZD for 4 weeks. Improvement of pathological symptoms was evaluated based on food intake, water intake, grip strength, gastric histopathological changes, gastric emptying rate, small intestinal propulsion rate, and average amplitude and frequency of smooth muscle strips. The mitochondrial ultrastructure was observed by transmission electron microscopy. The colocalization of LC3 and Parkin with mitochondria was detected by immunofluorescence. The expression and localization of Drp1 proteins were detected by immunohistochemistry. In vitro, GSMCs were treated with different concentrations of XSLJZD-CS for 24 h, followed by treatment with 20 μM carbon cyanide 3-chlorophenylhydrazone (CCCP) for 4 h. Cell viability, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mtROS), cellular ATP generation and mitochondrial Keima (mtKeima) expression were examined. Both in vivo and in vitro, gene expression was assessed by Western blotting. All experiments were performed in duplicate.

RESULTS

Disorders of the mitochondrial quality control system existed in gastric smooth muscle in FD spleen deficiency syndrome. XSLJZD administration promoted the contraction of gastric smooth muscle and restored mitochondrial function by downregulating the colocalization of LC3 or Parkin with mitochondria, reducing the ratio of LC3II/LC3I, decreasing the expression of PINK1, Parkin and Drp1 and increasing the expression of p62 to restore mitochondrial morphology and function. In vitro studies showed that the improvement in mitochondrial function by XSLJZD was related to PINK1-parkin-mediated mitochondrial quality control.

CONCLUSION

We demonstrated that XSLJZD can improve gastrointestinal motility disorder in functional dyspepsia with spleen deficiency syndrome, which was related to reconstruction of the mitochondrial quality control system by restraining PINK1/Parkin-mediated mitophagy and division. This study illustrates a novel clinical significance of herbal medicine in the treatment of FD and clarifies the important role of MQC in treating gastrointestinal motility disorder.

Interstitial Cells of Cajal: Potential Targets for Functional Dyspepsia Treatment Using Medicinal Natural Products

Introduction

The pathophysiology of functional dyspepsia (FD) remains uncertain, but the interstitial cells of Cajal (ICCs), pacemakers that regulate gastrointestinal motility, are garnering attention as key modulators and therapeutic targets in FD. This review comprehensively discusses the involvement of ICCs in the pharmacologic actions of FD and as therapeutic targets for herbal products for FD.

Methods

A search of the literature was performed using PubMed by pairing “interstitial cells of Cajal” with “medicinal plant, herbal medicine, phytotherapy, flavonoids, or traditional Chinese medicine (TCM).”

Results

From the 55 articles screened in the initial survey, 34 articles met our study criteria. The search results showed that herbal products can directly depolarize ICCs to generate pacemaker potentials and increase the expression of c-kit and stem cell factors, helping to repair ICCs. Under certain pathological conditions, medicinal plants also protect ICCs from oxidative stress and/or inflammation-induced impairment. Two representative herbal decoctions (Banhasasim-tang, 半夏泻心汤, and Yukgunja-tang, 六君子汤) have been shown to modulate ICC functions by both clinical and preclinical data.

Conclusion

This review strongly indicates the potential of herbal products to target ICCs and suggests that further ICC-based studies would be promising for the development of FD treatment agents.

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

BACKGROUND

Excessive autophagy and apoptosis of the interstitial cells of Cajal (ICC) have been identified in gastrointestinal (GI) motility disorders including slow transit constipation (STC). MicroRNA 222 (miR-222) has been shown to affect GI motility. This study aimed to explore whether miR-222 influences apoptosis and excessive autophagy of isolated ICC.

METHODS

miR-222, c-kit, and stem cell factor (SCF) were evaluated in colon tissues in STC rats compared with normal control by qRT-PCR and western blot analysis. The condition of autophagy of colon tissue was observed by transmission electron microscope. ICC were isolated from the colon of STC rats. Cell Counting Kit-8 (CCK-8) assay and wound healing assay were carried out to examine the cell viability and migration rate. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and Annexin V-Flourescein Isothiocyanate/Propidine Iodide (FITC/PI) apoptosis detection kit. Western blot analysis was performed to detect the c-kit and SCF expression; apoptosis-related proteins Bcl-2, Bax, caspase-3, and pro-caspase-3; and autophagy-related proteins LC3B and Beclin-1. The connection between miR-222 and c-kit was detected by bioinformatics and luciferase activity analysis.

RESULTS

miR-222 expression was significantly higher, whereas c-kit and SCF expressions were markedly lower in STC rats' colon tissue compared with normal control. Meanwhile, STC rats exhibited excessive autophagy in colon tissue than normal control. Inhibition of miR-222 expression promoted cell proliferation as well as migration and inhibited autophagy, whereas upregulation of miR-222 had the opposite effect. In addition, miR-222 upregulation induced apoptosis and excessive autophagy compared with normal controls (NC). Western blot analysis showed that miR-222 overexpression caused decreased c-kit and SCF protein levels compared with NC. Bioinformatics and luciferase activity analysis revealed that miR-222 could be a predictive regulator of c-kit.

CONCLUSION

miR-222 induces apoptosis and excessive autophagy of ICC and may serve as potential biomarker for ICC loss in STC.

Suppressive effect of Aurantii Fructus Immaturus and Atractylodis Macrocephalae Rhizoma on glutamic acid-induced autophagy of interstitial cells of Cajal

OBJECTIVE

To investigate the effects of Aurantii Fructus Immaturus (Zhishi, ZS) and Atractylodis Macrocephalae Rhizoma (Baizhu, BZ)-containing serum on glutamate-induced autophagy in rat colonic interstitial cells of Cajal (ICCs) and to analyze the underlying mechanism.

METHODS

Rat colonic ICCs cultured in vitro were identified by fluorescence and then stimulated with glutamic acid (5 mmol/L) for 24 h to establish a cell model of autophagy. The cells were then treated with different concentrations of ZSBZ-containing serum or rat serum. The viability of the ICCs was detected with cell counting kit-8 assays, and cell apoptosis rates were examined with flow cytometry. The ultrastructure and autophagosomes in the ICCs were observed using transmission electron microscopy. The effects of ZSBZ-containing serum on apoptosis-associated mediators were assessed by Western blotting and real-time quantitative polymerase chain reaction. In addition, microtubule-associated protein light chain 3 (LC3), p-phosphoinositide 3-kinase (p-PI3K), p-Akt and p-mammalian target of rapamycin (p-mTOR) expression was detected via Western blotting analysis.

RESULTS

Compared to those in the model group, ICC viability and apoptosis rates were significantly increased by ZSBZ-containing serum (P < 0.05). In addition, the expression levels of Beclin-1, LC3, p-PI3K, p-Akt and p-mTOR were significantly lower (P < 0.05) and Bcl-2 expression was higher in the ZSBZ-containing serum treatment groups than in the model group (P < 0.05).

CONCLUSION

Our findings demonstrated that ZSBZ protects glutamic acid-stimulated ICCs, and this beneficial effect may be mediated by a reduction in autophagy via inhibition of the PI3K/Akt/mTOR pathway.

Interstitial cells of Cajal are diminished in critically ill patients: Autopsy cases

OBJECTIVE

Gastrointestinal dysmotility in critically ill patients is important as enteral nutrition is crucial. However, normal gut motility is impaired under conditions of critical illness subsequent to severe insult. Interstitial cells of Cajal (ICC) form an extensive network associated with the myenteric plexus in the enteric nervous system. There are few reports about ICC distribution in critically ill patients. The aim of this study was to evaluate ICC in critically ill patients.

METHODS

Postmortem colon harvest was obtained from critically ill patients. Control specimens were obtained from patients without bowel movement problems who underwent hemicolectomy. The tissues were stained with c-Kit for ICC. The number of ICC was identified by counting from 10 high-power fields (HPFs).

RESULTS

Specimens from six patients were analyzed and compared with those from six control patients. All patients had abnormalities of crypt architecture and inflammatory cell infiltrations. Mucosal thickness tended to be lower in the critically ill patients than in the controls (147 ± 47 versus 231 ± 127 μm; P = 0.15). Muscle layer thickness tended to be higher in the critically ill patients than in the controls (494 ± 163 versus 394 ± 258 μm; P = 0.44). ICC in the critically ill patients were almost depleted in the colon compared with those in the controls. Significantly fewer ICC were present in the critically ill patients than in the controls (0.45 versus 7.25 cells/HPF; P < 0.05).

CONCLUSIONS

Critical illness is associated with diminished numbers of ICC in the colon. This finding could have implications for dysmotility in critically ill patients.

Effect of Chaihu Shugan Powder-Contained Serum on Glutamate-Induced Autophagy of Interstitial Cells of Cajal in the Rat Gastric Antrum

Gastrointestinal (GI) motility disorder is caused by excessive autophagy of the interstitial cells of Cajal (ICC). Chaihu Shugan Powder (CSP) is a traditional Chinese medicine with therapeutic benefits in GI motility disorders; however, the underlying mechanism of its therapeutic effect in GI disorders, especially autophagy of ICC, remains unclear. Thus, this study investigated the effects of CSP-contained serum on glutamate-induced autophagy in rat gastric ICC, exploring its underlying mechanism. In vitro cultured rat stomach ICC were identified by fluorescence microscopy and then stimulated with glutamate (5 mmol/L) for 3 h to establish the autophagy model. These cells were then treated with 10% CSP-containing serum or the autophagy inhibitor 3-methyladenine (3-MA; 5 mmol/L) for 24 h. The control group was cultured with only 10% serum containing physiological saline. The viability of ICC was measured by the CCK-8 assay. The ultrastructure and autophagosomes of ICC were observed using transmission electron microscopy. LC3 expression was detected by immunofluorescence, and LC3, Beclin1, Bcl2, and PI3KC3 expression was detected by western blot analysis. Transmission electron microscopy showed abundant endoplasmic reticulum, mitochondria, and other organelles in the control group, whereas the cells in the autophagy model control group had clear autophagic vacuoles, which were not apparent in both CSP and 3-MA groups. ICC viability was significantly increased by CSP and 3-MA interventions (P < 0.01), accompanied by a decrease in LC3 fluorescence (P < 0.01). Moreover, the expression levels of LC3II/I, Beclin1, and PI3KC3 were significantly decreased (all P < 0.01) with CSP and 3-MA treatment, while Bcl2 expression level was higher than that of the model group (P < 0.01). Thus, CSP can reduce autophagic damage by enhancing Bcl2 expression and downregulating the expression of LC3, Beclin1, and PI3KC3 to protect ICC. These results highlight the potential of CSP in the treatment of GI motility disorders.