Enterochromaffin Research Articles

Colonic 5-HT4 receptors are targets for novel prokinetic drugs.

5-HT4 receptors are G protein-coupled receptors that link to the stimulatory protein Gs which activates adenylate cyclase to increase intracellular cyclic AMP which then activates protein kinase A (PKA). 5-HT4 receptors are expressed by neurons in the central and peripheral nervous systems especially the enteric nervous system (ENS). In general, 5-HT4 receptors are stimulatory and their activation in the ENS enhances neurotransmitter release and propulsive motility patterns. 5-HT4 receptors are expressed by enterochromaffin (EC) cells, Goblet cells, and most enteric neurons. The study by Konen and colleagues in this issue of Neurogastroenterology and Motility features two novel 5-HT4 receptor agonists (5-HT4 -LA1 and 5-HT4 -LA-2) that are not absorbed from the gastrointestinal tract of mice and act locally in the colonic mucosa to stimulate propulsive motility. The authors show that 5-HT4 -LA1 and 5-HT4 -LA2 were not absorbed from the colon and that both drugs stimulated colonic transit when administered by gavage. Both agonists stimulated colonic glass bead expulsion, and 5-HT4 LA1 activation stimulated fecal output and increased fecal water content. These effects were detected in young and aged mice. 5-HT4 receptors were also localized to the epithelium of the human duodenum, ileum, and colon. These studies highlight novel 5-HT4 receptor agonists that have prokinetic actions on the GI tract. These drugs are not absorbed and act locally in the gut mucosa to stimulate propulsive motility while minimizing access to systemic 5-HT4 receptors and avoiding potential unwanted side effects.

Identification of a Metabolism-Related Signature for the Prediction of Survival in Endometrial Cancer Patients.

ObjectiveEndometrial cancer (EC) is one of the most common gynecologic malignancies. The present study aims to identify a metabolism-related biosignature for EC and explore the molecular immune-related mechanisms underlying the tumorigenesis of EC.MethodsTranscriptomics and clinical data of EC were retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Common differentially expressed metabolism-related genes were extracted and a risk signature was identified by using the least absolute shrinkage and selection operator (LASSO) regression analysis method. A nomogram integrating the prognostic model and the clinicopathological characteristics was established and validated by a cohort of clinical EC patients. Furthermore, the immune and stromal scores were observed and the infiltration of immune cells in EC cells was analyzed.ResultsSix genes, including CA3, HNMT, PHGDH, CD38, PSAT1, and GPI, were selected for the development of the risk prediction model. The Kaplan-Meier curve indicated that patients in the low-risk group had considerably better overall survival (OS) (P = 7.874e-05). Then a nomogram was constructed and could accurately predict the OS (AUC = 0.827, 0.821, 0.845 at 3-, 5-, and 7-year of OS). External validation with clinical patients showed that patients with low risk scores had a longer OS (p = 0.04). Immune/stromal scores and infiltrating density of six types of immune cells were lower in high-risk group.ConclusionsIn summary, our work provided six potential metabolism-related biomarkers as well as a nomogram for the prognosis of EC patients, and explored the underlying mechanism involved in the progression of EC.

Serotonin Deficiency Is Associated With Delayed Gastric Emptying

Gastrointestinal (GI) motility is regulated by serotonin (5-hydroxytryptamine [5-HT]), which is primarily produced by enterochromaffin (EC) cells in the GI tract. However, the precise roles of EC cell-derived 5-HT in regulating gastric motility remain a major point of conjecture. Using a novel transgenic mouse line, we investigated the distribution of EC cells and the pathophysiologic roles of 5-HT deficiency in gastric motility in mice and humans. We developed an inducible, EC cell-specific Tph1CreERT2/+ mouse, which was used to generate a reporter mouse line, Tph1-tdTom, and an EC cell-depleted line, Tph1-DTA. We examined EC cell distribution, morphology, and subpopulations in reporter mice. GI motility was measured invivo and exvivo in EC cell-depleted mice. Additionally, we evaluated 5-HT content in biopsy and plasma specimens from patients with idiopathic gastroparesis (IG). Tph1-tdTom mice showed EC cells that were heterogeneously distributed throughout the GI tract with the greatest abundance in the antrum and proximal colon. Two subpopulations of EC cells were identified in the gut: self-renewal cells located at the base of the crypt and mature cells observed in the villi. Tph1-DTA mice displayed delayed gastric emptying, total GI transit, and colonic transit. These gut motility alterations were reversed by exogenous provision of 5-HT. Patients with IG had a significant reduction of antral EC cell numbers and 5-HT content, which negatively correlated with gastric emptying rate. The Tph1CreERT2/+ mouse provides a powerful tool to study the functional roles of EC cells in the GI tract. Our findings suggest a new pathophysiologic mechanism of 5-HT deficiency in IG.

Human gastrointestinal epithelia of the esophagus, stomach, and duodenum resolved at single-cell resolution

The upper gastrointestinal tract, consisting of the esophagus, stomach, and duodenum, controls food transport, digestion, nutrient uptake, and hormone production. By single-cell analysis of healthy epithelia of these human organs, we molecularly define their distinct cell types. We identify a quiescent COL17A1high KRT15high stem/progenitor cell population in the most basal cell layer of the esophagus and detect substantial gene expression differences between identical cell types of the human and mouse stomach. Selective expression of BEST4, CFTR, guanylin, and uroguanylin identifies a rare duodenal cell type, referred to as BCHE cell, which likely mediates high-volume fluid secretion because of continual activation of the CFTR channel by guanylin/uroguanylin-mediated autocrine signaling. Serotonin-producing enterochromaffin cells in the antral stomach significantly differ in gene expression from duodenal enterochromaffin cells. We, furthermore, discover that the histamine-producing enterochromaffin-like cells in the oxyntic stomach express the luteinizing hormone, yet another member of the enteroendocrine hormone family.

Construction of green fluorescent carbon dots with high quantum yield for cancer cell recognition and Fe3+ detection

Abstract Herein, green-emitting nitrogen-doped carbon dots (CDs) were prepared by one-step solvothermal method. After purified by precipitation and silica column chromatography procedures, the pure CDs had uniform particle size and excellent fluorescence performance. Upon excitation at 430 nm wavelength, the CDs exhibited the maximum emission at 530 nm with absolute quantum yield (QY) of 16.5% in water. The CDs showed low cytotoxicity, remarkable biocompatibility to three cell lines (MCF-7, QSG-7701, EC cells) and good photostability to PH. Besides, different labeling distributions of CDs in cancer cells (MCF-7) and normal cells (QSG-7701) were achieved so that they could be used to identify cancer cell. Moreover, the CDs had good selectivity to detect Fe3+ ion in aqueous solution. The above hold them have great potential application in bioimaging and environmental monitoring.

YAP-TEAD up-regulates IRS2 expression to induce and deteriorate oesophageal cancer.

Oesophageal cancer (EC) represents a significant cause of cancer worldwide. Yes‐associated protein (YAP) is reported to correlate with the initiation of multiple cancers including EC, but the underlying mechanism remains elusive. The current study aimed to investigate the molecular mechanism of YAP‐TEAD in the occurrence and progression of EC. EC tissues and cells were obtained, followed by determination of the expression of YAP, c‐Jun, pc‐Jun and IRS2. The effect of YAP‐TEAD on the biological EC cell processes was explored through gain‐ and loss‐of‐function approaches. The interaction between YAP and TEAD was detected by co‐immunoprecipitation. The binding of TEAD to the c‐Jun promoter was determined using chromatin immunoprecipitation. Tumour formation in the nude mice was detected in order to ascertain the effect of YAP and IRS2 in vivo. We found elevated YAP in the EC tissues and cells. YAP silencing led to a decrease in EC cell proliferation, invasion and sphere formation. YAP‐TEAD complex bound to the promotor of c‐Jun, and c‐Jun led to an increase in the expression of IRS2 through the JNK/c‐Jun pathway. Additionally, pc‐Jun and phosphorylated JNK were localized in the nuclear in addition to displaying enhanced expression in the EC tissues. IRS2 overexpression negated the inhibition of cell proliferation, invasion and sphere formation triggering YAP silencing. YAP up‐regulated IRS2 and aggravated EC in vivo. Taken together, YAP‐TEAD activates the JNK/c‐Jun pathway to up‐regulate IRS2, ultimately promoting EC progression. Therefore, YAP‐TEAD inhibition could be a promising therapeutic approach for EC treatment.

Targeting RNF8 effectively reverses cisplatin and doxorubicin resistance in endometrial cancer

BackgroundEndometrial cancer (EC) is one of the most frequent gynecological malignancy worldwide. However, resistance to chemotherapy remains one of the major difficulties in the treatment of EC. Thus, there is an urgent requirement to understand mechanisms of chemoresistance and identify novel regimens for patients with EC. We found that protein and mRNA expression levels of RNF8 were significantly increased in both cisplatin and doxorubicin resistant EC cells. Cell survival assay showed that RNF deficiency significantly enhanced the sensitivity of resistant EC cells to cisplatin and doxorubicin (P < 0.01). In addition, chemoresistant EC cells exhibited increased NHEJ efficiency. Knockout of RNF8 in chemoresistant EC cells significantly reduced NHEJ efficiency and prolonged Ku80 retention on DSB. Moreover, cisplatin resistant AN3CA xenograft showed that RNF8 deficiency overcame cisplatin resistance. Our in vitro and in vivo assays provide evidence for RNF8, which is a NHEJ factor, serving as a promising, novel target in EC chemotherapy.

Pancreastatin Reduces Alternatively Activated Macrophages, Disrupts the Epithelial Homeostasis and Aggravates Colonic Inflammation. A Descriptive Analysis.

Ulcerative colitis (UC) is characterized by modifying alternatively activated macrophages (AAM) and epithelial homeostasis. Chromogranin-A (CHGA), released by enterochromaffin cells, is elevated in UC and is implicated in inflammation progression. CHGA can be cleaved into several derived peptides, including pancreastatin (PST), which is involved in proinflammatory mechanisms. Previously, we showed that the deletion of Chga decreased the onset and severity of colitis correlated with an increase in AAM and epithelial cells’ functions. Here, we investigated PST activity in colonic biopsies of participants with active UC and investigated PST treatment in dextran sulfate sodium (DSS)-induced colitis using Chga−/− mice, macrophages, and a human colonic epithelial cells line. We found that the colonic protein expression of PST correlated negatively with mRNA expression of AAM markers and tight junction (TJ) proteins and positively with mRNA expression of interleukin (IL)-8, IL18, and collagen in human. In a preclinical setting, intra-rectal administration of PST aggravated DSS-induced colitis by decreasing AAM’s functions, enhancing colonic collagen deposition and disrupting epithelial homeostasis in Chga+/+ and Chga−/− mice. This effect was associated with a significant reduction in AAM markers, increased colonic IL-18 release, and decreased TJ proteins’ gene expression. In vitro, PST reduced Chga+/+ and Chga−/− AAM polarization and decreased anti-inflammatory mediators’ production. Conditioned medium harvested from PST-treated Chga+/+ and Chga−/− AAM reduced Caco-2 cell migration, viability, proliferation, and mRNA levels of TJ proteins and increased oxidative stress-induced apoptosis and proinflammatory cytokines release. In conclusion, PST is a CHGA proinflammatory peptide that enhances the severity of colitis and the inflammatory process via decreasing AAM functions and disrupting epithelial homeostasis.

Role of peripheral 5-HT1D, 5-HT3 and 5-HT7 receptors in the mechanical allodynia induced by serotonin in mice

Serotonin (5-HT) acts as a neurotransmitter in the central nervous system (CNS) and as a mediator released by enterochromaffin cells to regulate intestinal motility. However, this amine also plays an important role as an inflammatory mediator and induces phenotypic changes of nociceptors. Despite the wide knowledge of the role of 5-HT in nociception, most studies have focused on its role in the CNS, while a clear information about its role in peripheral tissues is still lacking. In the present study, we investigated the role of peripheral 5-HT receptors in the nociceptive response induced by 5-HT or carrageenan in mice by using antagonists that target different 5-HT receptors. Mechanical nociceptive threshold was measured with an analgesimeter and evaluated after intraplantar (i.pl.) injection of 5-HT or carrageenan. 5-HT antagonists were injected via the i.pl. route. 5-HT (10, 20, 40 or 80 μg/paw) or carrageenan (100 μg/paw) induced mechanical allodynia. Pretreatment with isamoltane (5 μg; 5-HT1B antagonist) or ketanserine (1 μg; 5-HT2A antagonist) did not affect the mechanical allodynia induced by 5-HT. This response was inhibited by BRL 15572 (10 μg; 5-HT1D antagonist) or SB 269970 (25 μg; 5-HT7 antagonist). On the other hand, mechanical allodynia induced by 5-HT or carrageenan was exacerbated by ondansetron (10, 20 or 40 μg; 5-HT3 antagonist). The results indicate that activation of 5-HT1D and 5-HT7 receptors plays a role in the mechanical allodynia induced by 5-HT in mice. This study also demonstrates the inhibitory role of peripheral 5-HT3 receptors in the nociceptive response induced by 5-HT or carrageenan.

Physiological Role of Intestinotropic Glucagon Like Peptides in Health and Disease

Gastrointestinal hormones are the set of hormones which are secreted from the enteroendocrine cells of gastrointestinal tract. They coordinate functions like nutrient assimilation, food intake and signal transduction of various physiological processes. The remarkable enteroendocrine cells include enterochromaffin (EC) cells, enterochromaffin like (ECL) cells, G cells, D cells, M/Mo cells, S cells, K cells, I cells, N cells and L cells. Out of them, L cells in the ileum and colon secrete GLP-1, GLP-2, oxyntomodulin, peptide YY from glucagon coding gene (GCG) or proglucagon gene. GLP-1 is reported to perform functions like glycemia, glucose dependent insulin secretion, gastric emptying, regulation of food intake, β cell proliferation whereas GLP-2 is reported for variety of functions like regulation of mucosal growth in small and large intestine, enterocyte glucose transport nutrient absorption, inhibition of gastric emptying as well as gastric acid secretion, stimulation of intestinal blood flow, relaxation of intestinal smooth muscle. These intestinotropic glucagon like peptides channelize several homeostatic mechanisms and involve in the target specific actions all the way. The above mentioned functions of intestinotropic glucagon like peptides might be due torapid release by means of neural reflex and delayed release driven by the presence of food in the gut.

Gut bacteria-derived 5-hydroxyindole is a potent stimulant of intestinal motility via its action on L-type calcium channels.

Microbial conversion of dietary or drug substrates into small bioactive molecules represents a regulatory mechanism by which the gut microbiota alters intestinal physiology. Here, we show that a wide variety of gut bacteria can metabolize the dietary supplement and antidepressant 5-hydroxytryptophan (5-HTP) to 5-hydroxyindole (5-HI) via the tryptophanase (TnaA) enzyme. Oral administration of 5-HTP results in detection of 5-HI in fecal samples of healthy volunteers with interindividual variation. The production of 5-HI is inhibited upon pH reduction in in vitro studies. When administered orally in rats, 5-HI significantly accelerates the total gut transit time (TGTT). Deciphering the underlying mechanisms of action reveals that 5-HI accelerates gut contractility via activation of L-type calcium channels located on the colonic smooth muscle cells. Moreover, 5-HI stimulation of a cell line model of intestinal enterochromaffin cells results in significant increase in serotonin production. Together, our findings support a role for bacterial metabolism in altering gut motility and lay the foundation for microbiota-targeted interventions.

Incidence and patterns of secondary malignancies in patients with neuroendocrine neoplasms: A SEER database analysis.

374 Background: Neuroendocrine tumors (NETs) are comprised of a group of biologically and clinically heterogenous malignancies arising from a variety of anatomic sites, the majority of which lie within the gastrointestinal tract. Prior literature has reported on the association between NETs and other primary malignancies (OPM), most of which also end up being within the gastrointestinal tract, but these studies are limited by small sample sizes. We aim to further analyze the association of NETs and OPM on a larger scale using a population-based cancer registry. Methods: Malignant primary cancer with NET features were identified from the Surveillance Epidemiology and Ends Results (SEER) registry between 1975 and 2017. The histology/behavior of NET included carcinoid tumor, neuroendocrine carcinoma, pancreatic endocrine tumor, atypical carcinoid tumor, and other including insulinoma, glucagonoma, gastrinoma, VIPoma, somatostatinoma and enterochromaffin cell carcinoid. First NET observation from each patient was examined. Patients with NET were grouped into three categories: only one primary cancer with NET, first primary cancer with NET and first primary cancer without NET based on sequence number of primary cancer recorded in SEER. Distribution of NET between gastrointestinal (GI) and non-GI sites was described. Demographics were compared by NET sequence group and between GI and non-GI sites. Results: 45,896 patients with NET were analyzed (77.9% Caucasian, 47.0% male, median age 62.0 years). More than half (65.7%) of the NETs were observed in GI sites. Within the GI tract, 31.3% were in the small intestine, 25.1% in the rectum, 16.6% in pancreatobiliary, and &lt; 11% in other GI locations. Age at NET diagnosis was younger in those with GI NETs (median 60.0 vs 65.0, p &lt; 0.001 ). 71.2% of NET found in only cancer diagnosis, 10.4% of NET in first followed by a second primary malignancy, and 18.4% in a non-NET primary followed by NET. Mean age was 58.9 for NET primary only, 61.0 for NET primary first and 68.3 for non-NET primary first (p &lt; 0.0001). More Caucasian patients had non-NET primary first (82.3%) compared to NET primary only (76.9%) and NET primary first (75.5%). No gender differences were observed amongst the three groups. Carcinoid tumor histology was more prevalent in NET primary first (78.6%) compared to NET primary only (67.3%) and non-NET primary first (66.6%), while neuroendocrine carcinoma histology was more prevalent in NET only (27.4%) and non-NET first (29.3%) compared to NET first. Conclusions: 28.8% of patients with NETs were found to have OPM, either preceding or following their NET diagnosis. It is imperative that patients with NET undergo age-appropriate cancer screening to help identify any concurrent malignancies. Further research is warranted to identify the location of such additional malignancies and the timeframe in which they occur in relation to the NET.

Mechanisms underlying the promotion of 5-hydroxytryptamine secretion in enterochromaffin cells of constipation mice by Bifidobacterium and Lactobacillus.

5-Hydroxytryptamine (5-HT) could play a role in alleviating symptoms in constipation. However, the mechanism underlying the role of intestinal flora in the promotion of 5-HT secretion by enterochromaffin cells (ECs) and regulation of the gastrointestinal endocrine system remains unclear. A constipation mouse model was constructed, and the 5-HT, chromogranin A (CGA), substance P (SP), motilin (MTL), dopamine, and noradrenaline expression levels were measured using enzyme-linked immunosorbent assay(Elisa) and immunofluorescence, and key proteins, such as the transient receptor potential (TRP) ion channels/tryptophan hydroxylase (TPH) and olfactory receptor (OR), were determined using western blot. Flow cytometry and in vivo imaging were used to observe microbial colonization in the intestinal tracts of mice. Bifidobacterium animalis F1-7 (F1-7), Lactobacillus paraccasei F34-3 (F34-3), and Lactobacillus plantarum FWDG (FWDG) promoted 5-HT secretion. F1-7 and F34-3 induced CGA expression, increased catecholamine secretion, and activated the CGA/α2A adrenoreceptor (ADRα2A) cascade signal in ECs. FWDG increased noradrenaline levels and activated the ADRα2A signal in ECs. SP content increased in F1-7 and F34-3, and MTL expression increased in FWDG via the above signal. F1-7 and F34-3 downregulated TRPV4 and upregulated TPH, whereas FWDG upregulated OR2A4 for promoting 5-HT secretion by ECs. Finally, we observed that F1-7, F34-3, and FWDG were well colonized in the large intestine. F1-7, F34-3, and FWDG promoted 5-HT secretion in ECs of constipation mice by activating the CGA/ADRα2A cascade signal and regulating the TRP/TPH-OR pathways.

CircRNA circ_0004370 promotes cell proliferation, migration, and invasion and inhibits cell apoptosis of esophageal cancer via miR-1301-3p/COL1A1 axis.

BackgroundThe aim of this study was to investigate the circ_0004370 expression in EC, its effects on cell proliferation, apoptosis, migration, invasion, and epithelial–mesenchymal transition (EMT) process, and the underlying regulatory mechanisms in EC.MethodsThe protein levels of COL1A1 and EMT-related proteins were detected by western blot. The role of circ_0004370 on cell viability, proliferation, and apoptosis was analyzed by Cell Counting Kit-8 (CCK-8) assay, colony formation assay, and flow cytometry, respectively. The transwell assay was used to examine cell migration and invasion. The binding sites between miR-1301-3p and circ_0004370 or COL1A1 were predicted by starbase software and confirmed by dual-luciferase reporter assay and RNA pull-down assay.ResultsWe discovered that circ_0004370 was remarkably upregulated in EC tissues and cells. Knockdown of circ_0004370 inhibited cell proliferation, migration as well as invasion, and promoted apoptosis in vitro, while its effect was rescued by miR-1301-3p inhibition. And circ_0004370 mediated the EMT process in EC cells. Moreover, we explored its regulatory mechanism and found that circ_0004370 directly bound to miR-1301-3p and COL1A1 was verified as a target of miR-1301-3p. COL1A1 was highly expressed in EC cells and upregulation of COL1A1 reversed the effects of miR-1301-3p on cell proliferation, migration, invasion, and apoptosis. In addition, silencing of circ_0004370 reduced tumor volumes and weights in vivo. We showed that circ_0004370/miR-1301-3p/COL1A1 axis played the critical role in EC to regulate the cell activities.ConclusionCirc_0004370 promotes EC proliferation, migration and invasion, and EMT process and suppresses apoptosis by regulating the miR-1301-3p/COL1A1 axis, indicating that circ_0004370 may be used as a potential therapeutic target for EC.

An Incidental Finding of Duodenal Carcinoid Tumor

Neuroendocrine tumors (NETs) are rare, well-differentiated tumors that arise from enterochromaffin cells and are typically found within the digestive tract. Many NETs found within the gastrointestinal tract (GI) are located in the ileum, with duodenal NETs relatively rare. We describe a 56-year-old morbidly obese female who underwent upper gastrointestinal endoscopy (EGD) for refractory gastroesophageal reflux disease (GERD) and was incidentally diagnosed with a grade I NET within the duodenal bulb, which was subsequently resected. As these tumors are often indolent, it is important for clinicians to be cognizant of acting on these incidental findings to help prevent the systemic effects of carcinoid syndrome.

Serotonin as a Mitogen in the Gastrointestinal Tract: Revisiting a Familiar Molecule in a New Role.

Serotonin signaling is ubiquitous in the gastrointestinal (GI) system, where it acts as a neurotransmitter in the enteric nervous system (ENS) and influences intestinal motility and inflammation. Since its discovery, serotonin has been linked to cellular proliferation in several types of tissues, including vascular smooth muscle, neurons, and hepatocytes. Activation of serotonin receptors on distinct cell types has been shown to induce well-known intracellular proliferation pathways. In the GI tract, potentiation of serotonin signaling results in enhanced intestinal epithelial proliferation, and decreased injury from intestinal inflammation. Furthermore, activation of the type 4 serotonin receptor on enteric neurons leads to neurogenesis and neuroprotection in the setting of intestinal injury. It is not surprising that the mitogenic properties of serotonin are pronounced within the GI tract, where enterochromaffin cells in the intestinal epithelium produce 90% of the body’s serotonin; however, these proliferative effects are attributed to increased serotonin signaling within the ENS compartment as opposed to the intestinal mucosa, which are functionally and chemically separate by virtue of the distinct tryptophan hydroxylase enzyme isoforms involved in serotonin synthesis. The exact mechanism by which serotonergic neurons in the ENS lead to intestinal proliferation are not known, but the activation of muscarinic receptors on intestinal crypt cells indicate that cholinergic signaling is essential to this signaling pathway. Further understanding of serotonin’s role in mucosal and enteric nervous system mitogenesis may aid in harnessing serotonin signaling for therapeutic benefit in many GI diseases, including inflammatory bowel disease, malabsorptive conditions, and cancer.

An in vitro screening method for probiotics with antidepressant-like effect using the enterochromaffin cell model.

Certain probiotics can regulate the host's neurobehavioral function through the microbiota-gut-brain axis. However, screening these probiotics is mainly carried out in animal models, and is costly and inefficient. Herein, a putative enterochromaffin cell line (RIN14B) was used as an in vitro pre-screening model; 30 bacterial strains were tested for bacteria-stimulated tryptophan hydroxylase 1 gene (Tph1) expression and 5-hydroxytryptophan/5-hydroxytryptamine secretion. All strains were further validated for their neurobehavioral effects in chronic stress-induced depressive mice. Using partial least squares (PLS) modeling of in vitro and in vivo datasets, we found that the level of Tph1 mRNA in RIN14B significantly correlated with the performance of a forced swim test and sucrose preference test, and serum corticosterone level in chronically stressed mice. Four strains were identified as the best candidates among 30 strains using principal component analysis on all in vivo measures, and unsurprisingly, three of them could enhance Tph1 expression in RIN14B, which further proved that the RIN14B-based screening method (especially the detection of bacteria-stimulated Tph1 mRNA) has good predictive validity and screening efficiency for the strain's antidepressant-like capacity. Collectively, this study provides a novel in vitro method for screening probiotics (or other related bioproducts) with antidepressant-like potential.

Chloroacetanilide herbicide-induced rat enterochromaffin cell tumors: a case study within the context of the IPCS framework, for analyzing the relevance of a cancer mode of action for humans

The WHO International Programme on Chemical Safety (IPCS) framework for analyzing the relevance of a cancer mode of action (MoA) for humans (IPCS cancer-HRF) is an application to assess human relevance of tumorigenic hazards found through rodent bioassays. The chloroacetanilide herbicides, butachlor and alachlor, induced enterochromaffin-like (ECL) cell tumors in rat stomachs, at the highest doses. This study analyzed the human relevance of this tumor by applying the IPCS cancer-HRF using published data. In a postulated MoA, early key events (KEs) included decreased mucosal thickness in the fundic region, due to reduced parietal cells. The following KEs included increased pH of gastric acid and hypergastrinemia, leading to enhanced cell proliferation and hyperplasia, and resulting in the outcome of an ECL cell tumor. The data showed consistencies in dose-response and temporal concordance with the KEs and specificity in the tumor response, providing strengthened evidence of the KEs. While the early KE was not the same, similar MoAs have already been established for omeprazole and ciprofloxacin. The integrated data indicated that the postulated MoAs were biologically plausible. Alternative MoAs were excluded.. Based on sufficient evidence, an MoA was established in rats. When addressing chemically inducible MoAs of human relevance, KEs of hypergastrinemia and trophic ECL cell hyperplasia were judged to not be qualitatively and quantitatively plausible in humans. The MoA in rats is unlikely to be present in humans; however, the potential effects on parietal cells cannot be excluded. Thus, the IPCS cancer-HRF is very useful for assessing human relevance.

Rectal Neuroendocrine Tumor: Clinical Case Report

The rectal neuroendocrine tumor (RNT) is a rare neoplasm that initiates in the neuroendocrine cells of the digestive tract called Kulchitsky cells, which originate from Lieberkün crypts. About 50% of patients are asymptomatic and their diagnosis is made incidentally by routine colonoscopies. This clinical report presents a neoplasm considered rare in a young patient and emphasizes the importance of its early diagnosis. A 23-year-old man, without comorbidities, was referred to the referral service to investigation a single occurrence of postprandial abdominal pain in the left flank. Polypoid fragment of the rectal mucosa was extracted during a colonoscopy, making it possible to perform a complete removal with free margins of the rectal NET. After histopathological and immunohistochemical evaluation, the diagnosis of RNT grade 1 was made. Although RNT is rare and asymptomatic, early screening is necessary to facilitate diagnosis in the early stage of the disease, leading to a greater possibility of treatment and a better prognosis of the disease.

Oral Administration of Penicillin or Streptomycin May Alter Serum Serotonin Level and Intestinal Motility via Different Mechanisms.

Background/AimsEnterochromaffin cells (EC cells) constitute the largest population of enteroendocrine cells and release serotonin (5-HT) in response to mechanical and chemical cues of the gastrointestinal tract (GIT). How EC cells respond to altered microbiota such as due to antibiotic treatments remain poorly understood. We hypothesized that the pacemaker channel HCN2 might contribute to the regulation of EC cells functions and their responses to antibiotics-induced changes in intestinal flora.MethodsMice were given either penicillin or streptomycin or both in drinking water for 10 consecutive days. The changes in the profile of short chain fatty acids (SCFAs) in the cecum following penicillin or streptomycin treatments were tested by GC-MS. Serum 5-HT content, whole intestinal transit time, fecal water content, cecum weight and expression of HCN2 and TPH1 in cecal mucosa were measured. Ivabradine (a HCN channels blocker) was used to explore the role of HCN2 in penicillin-induced changes in 5-HT availability and intestinal motility.ResultsHCN2 immunofluorescence was detected on intestinal EC cells. Both penicillin and streptomycin caused significant reduction in total SCFAs in the cecum, with the penicillin-treated group showing greater reductions in butyrate, isobutyrate and isovalerate levels than the streptomycin group. The expression of HCN2 was increased in the mice treated with penicillin, whereas TPH1 expression was increased in the mice treated with streptomycin. Mice treated with antibiotics all had larger and heavier cecum, elevated serum 5-HT level and increased fecal water content. Besides, mice treated with penicillin had prolonged intestinal transit time. Intraperitoneal injection of Ivabradine attenuated the effect of penicillin on serum 5-HT level, cecum size and weight, intestinal motility, and fecal water content.ConclusionDisruptions of the intestinal flora structure due to oral administration of penicillin may significantly increase serum 5-HT level and inhibit intestinal motility, at least partially through up-regulating the expression of HCN2. Oral administration of streptomycin may alter 5-HT availability by up-regulating TPH1 expression thus increasing synthesis of 5-HT. Alterations of intestinal flora composition due to exposure to different antibiotics may regulate 5-HT availability and intestinal motility through different mechanisms.