Identifying MS4A6A+ macrophages as potential contributors to the pathogenesis of nonalcoholic fatty liver disease, periodontitis, and type 2 diabetes mellitus.

Purpose: Concrete epidemiological evidence has suggested the mutually-contributing effect respectively between nonalcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus (T2DM), and periodontitis (PD); however, their shared crosstalk mechanism remains an open issue. Method: The NAFLD, PD, and T2DM-related datasets were obtained from the NCBI GEO repository. Their common differentially expressed genes (DEGs) were identified and the functional enrichment analysis performed by the DAVID platform determined relevant biological processes and pathways. Then, the STRING database established a PPI network of such DEGs and topological analysis through Cytoscape 3.7.1 software along with the machine-learning analysis by the least absolute shrinkage and selection operator (LASSO) algorithm screened out hub characteristic genes. Their efficacy was validated by external datasets using the receiver operating characteristic (ROC) curve, and gene expression and location of the most robust one was determined using single-cell sequencing and immunohistochemical staining. Finally, the promising drugs were predicted through the CTD database, and the CB-DOCK 2 and Pymol platform mimicked molecular docking. Result: Intersection of differentially expressed genes from three datasets identified 25 shared DEGs of the three diseases, which were enriched in MHC II-mediated antigen presenting process. PPI network and LASSO machine-learning analysis determined 4 feature genes, of which the MS4A6A gene mainly expressed by macrophages was the hub gene and key immune cell type. Molecular docking simulation chosen fenretinide as the most promising medicant for MS4A6A+ macrophages. Conclusion: MS4A6A+ macrophages were suggested to be important immune-related mediators in the progression of NAFLD, PD, and T2DM pathologies.

Fut2 Deficiency Promotes Intestinal Stem Cell Aging by Damaging Mitochondrial Functions via Down-Regulating α1,2-Fucosylation of Asah2 and Npc1.

Fut2-mediated α1,2-fucosylation is important for gut homeostasis, including the intestinal stem cell (ISC). The stemness of ISC declines with age, and aging-associated ISC dysfunction is closely related to many age-related intestinal diseases. We previously found intestinal epithelial dysfunction in some aged Fut2 knockout mice. However, how Fut2-mediated α1,2-fucosylation affects ISC aging is still unknown. On this basis, the herein study aims to investigate the role of Fut2-mediated α1,2-fucosylation in ISC aging. Aging models in ISC-specific Fut2 knockout mice were established. ISCs were isolated for proteomics and N-glycoproteomics analysis. ISC functions and mitochondrial functions were examined in mice and organoids. Ulex europaeus agglutinin I chromatography and site-directed mutagenesis were used to validate the key target fucosylated proteins of Fut2. As a result, Fut2 knockout impaired ISC stemness and promoted aging marker expression in aged mice. Proteomics analysis indicated mitochondrial dysfunction in Fut2 knockout ISC. More injured mitochondria, elevated levels of reactive oxygen species, and decreased levels of adenosine 5'-triphosphate (ATP) in Fut2 knockout ISC were found. Moreover, respiratory chain complex impairment and mitophagy dysfunction in Fut2 knockout ISC were further noted. Finally, Fut2 was demonstrated to regulate mitochondrial functions mainly by regulating the α1,2-fucosylation of N-acyl sphingosine amidohydrolase 2 (Asah2) and Niemann-Pick type C intracellular cholesterol transporter 1 (Npc1). In conclusion, this study demonstrated the substantial role of Fut2 in regulating ISC functions during aging by affecting mitochondrial function. These findings provide novel insights into the molecular mechanisms of ISC aging and therapeutic strategies for age-related intestinal diseases.

Identification of CXC Chemokine Receptor 2 (CXCR2) as a Novel Eosinophils-Independent Diagnostic Biomarker of Pediatric Eosinophilic Esophagitis by Integrated Bioinformatic and Machine-Learning Analysis.

Background: Eosinophilic esophagitis (EoE) is a complex allergic condition frequently accompanied by various atopic comorbidities in children, which significantly affects their life qualities. Therefore, this study aimed to evaluate pivotal molecular markers that may facilitate the diagnosis of EoE in pediatric patients. Methods: Three available EoE-associated gene expression datasets in children: GSE184182, GSE 197702, GSE55794, along with GSE173895 were downloaded from the GEO database. Differentially expressed genes (DEGs) identified by "limma" were intersected with key module genes identified by weighted gene co-expression network analysis (WGCNA), and the shared genes went through functional enrichment analysis. The protein-protein interaction (PPI) network and the machine learning algorithms: least absolute shrinkage and selection operator (LASSO), random forest (RF), and XGBoost were used to reveal candidate diagnostic markers for EoE. The receiver operating characteristic (ROC) curve showed the efficacy of differential diagnosis of this marker, along with online databases predicting its molecular regulatory network. Finally, we performed gene set enrichment analysis (GSEA) and assessed immune cell infiltration of EoE/control samples by using the CIBERSORT algorithm. The correlations between the key diagnostic biomarker and immune cells were also investigated. Results: The intersection of 936 DEGs and 1446 key module genes in EoE generated 567 genes, which were primarily enriched in immune regulation. Following the construction of the PPI network and filtration by machine learning, CXCR2 served as a potential diagnostic biomarker of pediatric EoE with a perfect diagnostic efficacy (AUC = ~1.00) in regional tissue/peripheral whole blood samples. Multiple infiltrated immune cells were observed to participate in disrupting the homeostasis of esophageal epithelium to varying degrees. Conclusion: The immune-correlated CXCR2 gene was proved to be a promising diagnostic indicator for EoE, and dysregulated regulatory T cells (Tregs)/neutrophils might play a crucial role in the pathogenesis of EoE in children.

Insights into the liver-eyes connections, from epidemiological, mechanical studies to clinical translation.

Maintenance of internal homeostasis is a sophisticated process, during which almost all organs get involved. Liver plays a central role in metabolism and involves in endocrine, immunity, detoxification and storage, and therefore it communicates with distant organs through such mechanisms to regulate pathophysiological processes. Dysfunctional liver is often accompanied by pathological phenotypes of distant organs, including the eyes. Many reviews have focused on crosstalk between the liver and gut, the liver and brain, the liver and heart, the liver and kidney, but with no attention paid to the liver and eyes. In this review, we summarized intimate connections between the liver and the eyes from three aspects. Epidemiologically, we suggest liver-related, potential, protective and risk factors for typical eye disease as well as eye indicators connected with liver status. For molecular mechanism aspect, we elaborate their inter-organ crosstalk from metabolism (glucose, lipid, proteins, vitamin, and mineral), detoxification (ammonia and bilirubin), and immunity (complement and inflammation regulation) aspect. In clinical application part, we emphasize the latest advances in utilizing the liver-eye axis in disease diagnosis and therapy, involving artificial intelligence-deep learning-based novel diagnostic tools for detecting liver disease and adeno-associated viral vector-based gene therapy method for curing blinding eye disease. We aim to focus on and provide novel insights into liver and eyes communications and help resolve existed clinically significant issues.

Fucose promotes intestinal stem cell-mediated intestinal epithelial development through promoting Akkermansia-related propanoate metabolism.

Intestinal stem cells (ISCs) are critical for the development and rapid turnover of intestinal epithelium. The regulatory effects of gut microbiota and their metabolites on ISCs stemness remain elusive. Fucose has been demonstrated to mediate host-microbe interactions in the intestine. However, the association between fucose, gut bacteria, and ISCs stemness remains unclear. To investigate the effects of fucose on ISCs-mediated intestinal epithelial cells (IECs) development, we administered fucose to 4-week-old mice for 4 weeks. ISCs stemness, IECs proliferation, and differentiation were examined. Variations in gut microbes and metabolism were detected using 16S rDNA sequencing and metabolomic analysis. Fucose was added to the bacterial culture medium to further study its effects on metabolism. Crypts were isolated from the mouse ileum for organoids culture in vitro to evaluate the effects of metabolites and the underlying mechanism. The results showed that fucose accelerated ISCs proliferation and secretory lineage differentiation in mice, whereas antibiotics eliminated these effects. The composition and functions of gut bacteria were altered by fucose treatment, while significant increases in Akkermansia and propanoate metabolism were noted. Propionic acid and propionate have been shown to promote organoid development. Fucose fermentation increases the production of propionic acid in Akkermansia muciniphila and enhances its ability to increase the stemness of ISCs. Moreover, ileal contents from fucose-treated mice promoted organoid development in a Gpr41/Gpr43-dependent manner. Fucose administration activates the Wnt signaling pathway in ISCs, and Wnt inhibitors suppress the effects of fucose. We conclude that fucose accelerates ISC-mediated intestinal epithelial development by promoting Akkermansia-related propanoate metabolism. These findings provide new insights into the promotion of gut homeostasis and the application potential of fucose as a prebiotic.

Fucose ameliorates the proinflammatory property of Fusobacterium nucleatum in colitis via altering its metabolism.

Introduction: Previous studies reported that fucose plays a protective role in inhibiting pathogens. Fusobacterium nucleatum (Fn) was recently found to promote the progression of colitis. However, the effects of fucose on Fn are poorly understood. This study aimed to explore whether fucose could ameliorate the proinflammatory property of Fn in colitis and the underlying mechanisms. Methods: To validate our hypothesis, mice were administrated with Fn and fucose-treated Fn (Fnf) before dextran sulfate sodium (DSS) treatment to establish Fn related colitis model. The metabolism variation of Fn was detected by metabolomic analysis. To verify the effects of bacterial metabolites on intestinal epithelial cells (IECs), Caco-2 cells were treated with bacterial supernatant. Results: More severe inflammation, intestinal barrier damage, autophagy block, and apoptosis in the colon were noted in DSS mice that were administrated with Fn or Fnf. However, the severity degree in Fnf+DSS group was less compared to Fn+DSS group. Metabolic pathways of Fn were altered after fucose treatment and proinflammatory metabolites were decreased. The supernatant of Fnf induced a lower level of inflammation than Fn in Caco-2 cells. One of the decreased metabolites, homocysteine thiolactone (HT), was proven to induce inflammatory effects in Caco-2 cells. Discussion: In conclusion, fucose ameliorates the proinflammatory property of Fn via altering its metabolism and these findings provide evidence for the application of fucose as functional food or prebiotic in the treatment of Fn related colitis.

FUT2-dependent fucosylation of HYOU1 protects intestinal stem cells against inflammatory injury by regulating unfolded protein response.

The intestinal epithelial repair after injury is coordinated by intestinal stem cells (ISCs). Fucosylation catalyzed by fucosyltransferase 2 (FUT2) of the intestinal epithelium is beneficial to mucosal healing but poorly defined is the influence on ISCs. The dextran sulfate sodium (DSS) and lipopolysaccharide (LPS) model were used to assess the role of FUT2 on ISCs after injury. The apoptosis, function, and stemness of ISCs were analyzed using intestinal organoids from WT and Fut2ΔISC (ISC-specific Fut2 knockout) mice incubated with LPS and fucose. N-glycoproteomics, UEA-1 chromatography, and site-directed mutagenesis were monitored to dissect the regulatory mechanism, identify the target fucosylated protein and the corresponding modification site. Fucose could alleviate intestinal epithelial damage via upregulating FUT2 and α-1,2-fucosylation of ISCs. Oxidative stress, mitochondrial dysfunction, and cell apoptosis were impeded by fucose. Meanwhile, fucose sustained the growth and proliferation capacity of intestinal organoids treated with LPS. Contrarily, FUT2 depletion in ISCs aggravated the epithelial damage and disrupted the growth and proliferation capacity of ISCs via escalating LPS-induced endoplasmic reticulum (ER) stress and initiating the IRE1/TRAF2/ASK1/JNK branch of unfolded protein response (UPR). Fucosylation of the chaperone protein HYOU1 at the N-glycosylation site of asparagine (Asn) 862 mediated by FUT2 was identified to facilitate ISCs survival and self-renewal, and improve ISCs resistance to ER stress and inflammatory injury. Our study highlights a fucosylation-dependent protective mechanism of ISCs against inflammation, which may provide a fascinating strategy for treating intestinal injury disorders.

Intestinal epithelium-specific Fut2 deficiency promotes colorectal cancer through down-regulating fucosylation of MCAM.

BACKGROUND: Our previous study showed that fucosyltransferase 2 (Fut2) deficiency is closely related to colitis. Colitis increases the risk for the development of colorectal cancer (CRC). This study aimed to investigate the effect and underlying mechanism of action of Fut2 in CRC. METHODS: Intestinal epithelium-specific Fut2 knockout (Fut2△IEC) mice were used in this study. CRC was induced using azoxymethane (AOM) and dextran sulfate sodium (DSS). Immunofluorescence was used to examine the fucosylation levels. Proteomics and N-glycoproteomics analyses, Ulex Europaeus Agglutinin I (UEA-I) affinity chromatography, immunoprecipitation, and rescue assay were used to investigate the mechanism of Fut2 in CRC. RESULTS: The expression of Fut2 and α-1,2-fucosylation was lower in colorectal tumor tissues than in the adjacent normal tissues of AOM/DSS-induced CRC mice. More colorectal tumors were detected in Fut2△IEC mice than in control mice, and significant downregulation of melanoma cell adhesion molecule (MCAM) fucosylation was detected in the colorectal tumor tissues of Fut2△IEC mice. Overexpression of Fut2 inhibited cell proliferation, invasion and tumor metastasis in vivo and in vitro in SW480 and HCT116 cells. Moreover, fucosylation of MCAM may be a mediator of Fut2 in CRC. Peracetylated 2-F-Fuc, a fucosyltransferase inhibitor, repressed fucosylation modification of MCAM and reversed the inhibitory effects of Fut2 overexpression on SW480 cell proliferation, migration, and invasion. Our results indicate that Fut2 deficiency in the intestinal epithelium promotes CRC by downregulating the fucosylation of MCAM. CONCLUSIONS: The regulation of fucosylation may be an potential therapy for CRC, especially in patients with Fut2 gene defects.

Promoting Effect of L-Fucose on the Regeneration of Intestinal Stem Cells through AHR/IL-22 Pathway of Intestinal Lamina Propria Monocytes.

The recovery of the intestinal epithelial barrier is the goal for curing various intestinal injurious diseases, especially IBD. However, there are limited therapeutics for restoring intestinal epithelial barrier function in IBD. The stemness of intestinal stem cells (ISCs) can differentiate into various mature intestinal epithelial cells, thus playing a key role in the rapid regeneration of the intestinal epithelium. IL-22 secreted by CD4+ T cells and ILC3 cells was reported to maintain the stemness of ISCs. Our previous study found that L-fucose significantly ameliorated DSS-induced colonic inflammation and intestinal epithelial injury. In this study, we discovered enhanced ISC regeneration and increased intestinal IL-22 secretion and its related transcription factor AHR in colitis mice after L-fucose treatment. Further studies showed that L-fucose promoted IL-22 release from CD4+ T cells and intestinal lamina propria monocytes (LPMCs) via activation of nuclear AHR. The coculture system of LPMCs and intestinal organoids demonstrated that L-fucose stimulated the proliferation of ISCs through an indirect manner of IL-22 from LPMCs via the IL-22R-p-STAT3 pathway, and restored TNF-α-induced organoid damage via IL-22-IL-22R signaling. These results revealed that L-fucose helped to heal the epithelial barrier by accelerating ISC proliferation, probably through the AHR/IL-22 pathway of LPMCs, which provides a novel therapy for IBD in the clinic.

Necrosulfonamide ameliorates intestinal inflammation via inhibiting GSDMD-medicated pyroptosis and MLKL-mediated necroptosis.

Inflammatory bowel disease (IBD) is a chronic relapsing disorder of the gastrointestinal tract, while the present therapeutic efficacy is insufficient. In recent years, numerous studies have shown that necrosulfonamide (NSA) played a protective role in many inflammatory diseases by blocking mixed lineage kinase domain-like protein (MLKL) polymerization. However, the protective effect of NSA in dextran sodium sulfate (DSS)-induced colitis has not been reported. In the present study, we used DSS to establish mouse models of acute colitis to explore the proactive effect of NSA. Our study showed that NSA alleviated symptoms of DSS-induced colitis through reducing weight loss and disease activity index (DAI) score. Furthermore, NSA inhibited macrophages and CD4+/CD8 + T-cell accumulation in colon tissue caused by DSS. In addition, we found that NSA had the therapeutic effects on DSS-induced colitis. Mechanistically, we detected the expression level of phosphorylated MLKL, the release of LDH, cytokines, and N-gasdermin D (N-GSDMD) to examine necroptosis and pyroptosis pathways. We found NSA alleviated the severity of DSS-induced colitis by inhibiting the expressions of phosphorylated MLKL and N-GSDMD in vivo. In vitro experiments, we found NSA inhibited the release of inflammatory factors and LDH and the expressions of N-GSDMD in bone marrow-derived macrophages. Furthermore, we found NSA inhibited the expression of phosphorylated MLKL and necroptosis of NCM460 cell through western blot and flow cytometer. In general, this study reveals that NSA inhibits pyroptosis and necroptosis pathways to eventually alleviate intestinal inflammation, which may serve as a potential candidate for IBD therapy.

Association of stress and functional gastrointestinal disorders in high school graduates.

BACKGROUND: Psychosocial factors are seemed as important causes of functional gastrointestinal disorders (FGIDs). However, the role of stress in FGIDs in high school students under the pressure of college entrance examination is largely unknown. The aim of this study is to investigate the association between the stress and FGIDs in high school graduates. METHODS: A cross-sectional survey was conducted in randomly selected high school fresh graduates. Questionnaires concerned health condition, living habits, gastrointestinal symptoms and life stress were given out and be finished voluntarily. Participants were diagnosed as FGIDs based on the Rome IV criteria. RESULTS: Stress level of FGIDs population was higher than control group and stress was independent predicted factor of high risk of FGIDs. The stressor "changes" was significantly correlated with functional gastroduodenal disorders (OR1.118(1.011-1.238)). Stressor "frustration" was significantly correlated with functional bowel disorders (OR1.038(1.006-1.071)). "Physiological reaction" was correlated with functional bowel disease and functional gastroduodenal disorders + functional bowel disorders (OR1.027(1.007-1.046) and OR1.055(1.000-1.113)). Students with more than one gastrointestinal symptom exhibited higher stress level. Moreover, there was mediation effect of stress in the association between gender, sleep quality, allergies and FGIDs. LIMITATIONS: This was a cross-section study and the sample included in the study were only from Wuhan, China. CONCLUSIONS: Our findings illustrated the predicted and mediated role of stress in FGIDs in high school fresh graduates. Different stressors and reactions to stressors contributed to different FGIDs. Intervening measures aimed at stress coping strategies were warranted for students in daily school life.

Gut microbiota-mediated lysophosphatidylcholine generation promotes colitis in intestinal epithelium-specific Fut2 deficiency.

BACKGROUND AND AIMS: Previous study disclosed Fucosyltransferase 2 (Fut2) gene as a IBD risk locus. This study aimed to explore the mechanism of Fut2 in IBD susceptibility and to propose a new strategy for the treatment of IBD. METHODS: Intestinal epithelium-specific Fut2 knockout (Fut2△IEC) mice was used. Colitis was induced by dextran sulfate sodium (DSS). The composition and diversity of gut microbiota were assessed via 16S rRNA analysis and the metabolomic findings was obtained from mice feces via metabolite profiling. The fecal microbiota transplantation (FMT) experiment was performed to confirm the association of gut microbiota and LPC. WT mice were treated with Lysophosphatidylcholine (LPC) to verify its impact on colitis. RESULTS: The expression of Fut2 and α-1,2-fucosylation in colonic tissues were decreased in patients with UC (UC vs. control, P = 0.036) and CD (CD vs. control, P = 0.031). When treated with DSS, in comparison to WT mice, more severe intestinal inflammation and destructive barrier functions in Fut2△IEC mice was noted. Lower gut microbiota diversity was observed in Fut2△IEC mice compared with WT mice (p < 0.001). When exposed to DSS, gut bacterial diversity and composition altered obviously in Fut2△IEC mice and the fecal concentration of LPC was increased. FMT experiment revealed that mice received the fecal microbiota from Fut2△IEC mice exhibited more severe colitis and higher fecal LPC concentration. Correlation analysis showed that the concentration of LPC was positively correlated with four bacteria-Escherichia, Bilophila, Enterorhabdus and Gordonibacter. Furthermore, LPC was proved to promote the release of pro-inflammatory cytokines and damage epithelial barrier in vitro and in vivo. CONCLUSION: Fut2 and α-1,2-fucosylation in colon were decreased not only in CD but also in UC patients. Gut microbiota in Fut2△IEC mice is altered structurally and functionally, promoting generation of LPC which was proved to promote inflammation and damage epithelial barrier.

L-fucose ameliorates the carcinogenic properties of Fusobacterium nucleatum in colorectal cancer.

Fusobacterium nucleatum (Fn) is considered a promoting factor in colorectal cancer (CRC); however, only a few studies have investigated therapies against Fn. L-fucose is a natural monosaccharide that has prebiotic potential. The present study aimed to investigate the effect of L-fucose on the carcinogenic properties of Fn. The HCT116 and SW480 colon cancer cell lines were treated with Fn and Fn+L-fucose (Fnf), respectively. The Cell Counting Kit-8 (CCK-8), colony formation, Transwell migration and invasion and wound healing assays were performed to assess the proliferative, migratory and invasive abilities of the cells, respectively. Western blot was performed to detect the protein levels of jak/stat3 pathway components and EMT. The results of the CCK-8, colony formation, Transwell and wound healing assays demonstrated that treatment with Fn significantly enhanced the proliferative, migratory and invasive abilities of HCT116 and SW480 colon cancer cells. Notably, these effects were significantly reversed following addition of L-fucose. Furthermore, L-fucose inhibited the carcinogenic properties of Fn to activate the stat3 pathway and epithelial-to-mesenchymal transition. Taken together, the results of the present study suggest that L-fucose ameliorates the carcinogenic properties of Fn in vitro, and thus may serve as a novel therapeutic target for flora-related colon cancer.

Diarrhea and altered inflammatory cytokine pattern in severe coronavirus disease 2019: Impact on disease course and in-hospital mortality.

BACKGROUND AND AIM: Dynamic changes of immunocyte subsets and inflammatory profiles in coronavirus disease 2019 (COVID-19) patients with gastrointestinal symptoms were undetermined. METHODS: A single-center retrospective analysis of 409 severe, hospitalized COVID-19 patients from 20 January to 29 February 2020 was performed. The longitudinal characteristics of immune inflammatory cytokines in patients with/without diarrhea were analyzed. The relations of diarrhea and immuno-inflammatory factors with illness course and clinical outcomes were further explored. RESULTS: Diarrhea was more common and more serious with longer duration (4.9 ± 1.5 vs 4.2 ± 1.5 days, P = 0.039) and higher frequency (5.5 ± 2.1 vs 4.0 ± 2.0 times/day, P = 0.001) in deceased patients than in the survivors. Also, diarrhea patients were more inclined to develop multi-organ damage: survivors have longer illness course (media 41.0 vs 36.0 days, P = 0.052) and hospital stays (media 27.0 vs 23.0 days, P = 0.041), and the deceased patients had higher mortality (33.0% vs 22.6%, P = 0.045) and earlier death (media 20.0 vs 25.0 days, P = 0.038). Progressively, neutrophilia and lymphopenia, especially the declined CD8+ T cells, were demonstrated in diarrhea patients relative to the non-diarrhea cases. The inflammatory cytokines including IL-6, IL-10, and TNF-α were intensively increased in patients with diarrhea. The multivariable logistic analysis showed longer duration of diarrhea (P = 0.036), higher neutrophil counts (P = 0.011), and lower lymphocyte counts (P < 0.001) were independent risk factors of in-hospital death. The proportional hazards model indicated that longer duration of diarrhea (P = 0.002), higher frequency of diarrhea (P = 0.058), higher neutrophil counts (P = 0.001), lower lymphocyte counts (P = 0.035), and decreased proportion of CD8+ T cells (P < 0.001) were independently associated with longer illness course of the survivors. CONCLUSIONS: Diarrhea patients were more likely to present with neutrophilia, lymphopenia, and cytokine storm and to develop multi-organ damage. The inflammatory patterns were independent factors associated with illness course of the survivors and in-hospital death of severe COVID-19.

Lactobacillus rhamnosus attenuates intestinal inflammation induced by Fusobacterium nucleatum infection by restoring the autophagic flux.

Autophagy plays a dual role in the responses to the gut microflora. The present study aimed to examine the effects of Lactobacillus rhamnosus (L. rhamnosus) on Fusobacterium nucleatum (F. nucleatum)­induced intestinal dysfunction and to elucidate the underlying mechanisms, with particular focus on autophagy. Inflammatory models were established by treatment with L. rhamnosus following F. nucleatum intervention using cells or a mouse model of dextran sulfate sodium (DSS)­induced acute colitis. Autophagosomes were visualized by confocal microscopy following transfection with a tandem GFP­mCherry­LC3 construct and also by transmission electron microscopy. Autophagy­associated protein levels were examined by western blot analysis and immunohistochemistry. It was observed that F. nucleatum induced the production of pro­inflammatory cytokines in Caco­2 cells and aggravated DSS­induced acute colitis. The autophagic flux was impaired following infection with F. nucleatum. L. rhamnosus treatment attenuated the inflammation induced by F. nucleatum infection and effectively recovered the impaired autophagic flux. In addition, the production of pro­inflammatory cytokines induced by F. nucleatum was enhanced with autophagy inhibitors or the RNA interference of autophagy­related gene 16 like 1 (Atg16L1) in Caco­2 cells. Notably, this inhibition of autophagy weakened the effects of L. rhamnosus. Finally, the PI3K/AKT/mTOR pathway was found to be involved in this process. On the whole, the present study demonstrates that the mediation of autophagy by L. rhamnosus may be involved in the protective effects against F. nucleatum­related intestinal inflammation. Thus, L. rhamnosus treatment may prove to be a novel therapeutic strategy for F. nucleatum­realated gut disorders.

Immuno-Inflammatory Characteristics in Low Severity COVID-19 Patients with Digestive Symptoms.

AIM: The outbreak of Coronavirus Disease 2019 (COVID-19) has resulted in a global pandemic, with the main manifestations being of respiratory nature, including pneumonia. It is noteworthy that digestive symptoms are also observed in COVID-19 patients. In this article, we describe the immuno-inflammatory characteristics of low severity COVID-19 patients with digestive symptoms. METHODS: Patients with mild symptoms of COVID-19 were split into three groups based on the patients' symptoms. The first group displayed digestive symptoms only, the second group displayed respiratory symptoms only, and the last group displayed both digestive and respiratory symptoms. Patients were discharged based on negative results of rRT-PCR testing for SARS-CoV-2 from at least two sequential respiratory tract specimens collected ≥24 hours apart. Multiorgan function and immuno-inflammatory characteristics were analyzed for all of the three groups. RESULTS: Mild liver damage and activation of the immuno-inflammatory system were the most common abnormalities observed in patients with mild COVID-19 symptoms but no significant differences were found (P > 0.05). Patients with digestive symptoms were more likely to have slightly higher and later peak values of inflammatory cytokines during the subsequent course of disease (P < 0.05). In addition, a significant correlation between IL-2 and TNF level was found in the first group which included patients with digestive symptoms only (P < 0.05). CONCLUSIONS: Patients with mild cases of COVID-19 only displaying digestive symptoms are a special subtype. Patients in this group were more likely to have slightly higher and delayed peak values of inflammatory cytokines during the subsequent course of the disease. Prevention and clinical management of this type should be taken into consideration.

Digestive Symptoms in COVID-19 Patients With Mild Disease Severity: Clinical Presentation, Stool Viral RNA Testing, and Outcomes.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) most commonly presents with respiratory symptoms, including cough, shortness of breath, and sore throat. However, digestive symptoms also occur in patients with COVID-19 and are often described in outpatients with less severe disease. In this study, we sought to describe the clinical characteristics of COVID-19 patients with digestive symptoms and mild disease severity. METHODS: We identified COVID-19 patients with mild disease and one or more digestive symptoms (diarrhea, nausea, and vomiting), with or without respiratory symptoms, and compared them with a group presenting solely with respiratory symptoms. We followed up patients clinically until they tested negative for COVID-19 on at least 2 sequential respiratory tract specimens collected ≥24 hours apart. We then compared the clinical features between those with digestive symptoms and those with respiratory symptoms. RESULTS: There were 206 patients with low severity COVID-19, including 48 presenting with a digestive symptom alone, 69 with both digestive and respiratory symptoms, and 89 with respiratory symptoms alone. Between the 2 groups with digestive symptoms, 67 presented with diarrhea, of whom 19.4% experienced diarrhea as the first symptom in their illness course. The diarrhea lasted from 1 to 14 days, with an average duration of 5.4 ± 3.1 days and a frequency of 4.3 ± 2.2 bowel movements per day. Concurrent fever was found in 62.4% of patients with a digestive symptom. Patients with digestive symptoms presented for care later than those with respiratory symptoms (16.0 ± 7.7 vs 11.6 ± 5.1 days, P < 0.001). Nevertheless, patients with digestive symptoms had a longer duration between symptom onset and viral clearance (P < 0.001) and were more likely to be fecal virus positive (73.3% vs 14.3%, P = 0.033) than those with respiratory symptoms. DISCUSSION: We describe a unique subgroup of COVID-19 patients with mild disease severity marked by the presence of digestive symptoms. These patients are more likely to test positive for viral RNA in stool, to have a longer delay before viral clearance, and to experience delayed diagnosis compared with patients with only respiratory symptoms.