Glutamine deficiency links clindamycin-induced dysbiosis and intestinal barrier dysfunction in mice

Microbiome and metabolomic changes in rabbits induced by Folium sennae

Diarrhea is a serious health concern in livestock, affecting productivity and animal welfare. However, it remains a significant threat. Various practical therapies are being explored, such as prebiotics, probiotics, and organic acids, as well as chemical treatments including antibiotics, to combat this disorder. This study aims to explore the microbiome and metabolomic changes in rabbits with diarrhea. In the present study, diarrhea was induced in rabbits via oral gavage of Folium Sennae (FSAE), to assess body weights, diarrhea index, serum biochemical indicators, histopathology, microbiota, and metabolomics changes. Our study provides new insights into the mechanism of FSAE-induced diarrhea in rabbits and offers a novel mechanism for the interaction between gut microbiota, metabolomics, and gastrointestinal (GIT) dysfunction. Our results revealed that rabbits receiving FSAE showed a markedly higher diarrhea index and reduced body weight. Notably, levels of somatostatin, substance P, cholecystokinin, 5-hydroxytryptamine, vasoactive intestinal peptide, and acetylcholinesterase were significantly increased compared to control (P <  0.01). However, the levels of gastrin, motilin, enkephalin, and β-Endorphins were significantly decreased (P <  0.01). Microbial analysis revealed a significant reduction in microbial diversity (Shannon, Simpson, ACE, and chao1) and a decrease in Firmicutes, Campilobacterota, and Proteobacteria populations in FSAE-exposed rabbits. Additionally, 13 key metabolites associated with taurine and hypotaurine metabolism, alanine, aspartate and glutamate metabolism, starch and sucrose metabolism, histidine metabolism, and citrate cycle were identified in the colonic tissues. The present study concludes that FSAE-induced diarrhea in rabbits is associated with significant histopathological alterations in the colon, dysregulation of serum biochemical markers, and dysbiosis in metabolomics and gut microbiota. Our findings offer a novel model for investigating GIT dysfunction and its potential treatments.

Identification of subclusters and prognostic genes based on GLS-associated molecular signature in ulcerative colitis

Ulcerative colitis (UC) is a chronic and recurrent inflammatory disease that affects the colon and rectum. The response to treatment varies among individuals with UC. Therefore, the aim of this study was to identify and explore potential biomarkers for different subtypes of UC and examine their association with immune cell infiltration. We obtained UC RNA sequencing data from the GEO database, which included the training set GSE92415 and the validation set GSE87473 and GSE72514. UC patients were classified based on GLS and its associated genes using consensus clustering analysis. We identified differentially expressed genes (DEGs) in different UC subtypes through a differential expression analysis of the training cohort. Machine learning algorithms, including Weighted Gene Co-Expression Network Analysis (WGCNA), Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine Recursive Feature Elimination (SVM-RFE), were utilized to identify marker genes for UC. The CIBERSORT algorithm was used to determine the abundance of various immune cells in UC and their correlation with UC signature genes. Finally, we validated the expression of GLS through in vivo and ex vivo experiments. The expression of GLS was found to be elevated in patients with UC compared to normal patients. GLS and its related genes were able to classify UC patients into two subtypes, C1 and C2. The C1 subtype, as compared to the C2 subtype, showed a higher Mayo score and poorer treatment response. A total of 18 DEGs were identified in both subtypes, including 7 up-regulated and 11 down-regulated genes. Four UC signature genes (CWH43, HEPACAM2, IL24, and PCK1) were identified and their diagnostic value was validated in a separate cohort (AUC > 0.85). Furthermore, we found that UC signature biomarkers were linked to the immune cell infiltration. CWH43, HEPACAM2, IL24, and PCK1 may serve as potential biomarkers for diagnosing different subtypes of UC, which could contribute to the development of targeted molecular therapy and immunotherapy for UC.

Lactiplantibacillus plantarum Y42 in Biofilm and Planktonic States Improves Intestinal Barrier Integrity and Modulates Gut Microbiota of Balb/c Mice

In our previous study, Lactiplantibacillus plantarum Y42 showed some potential probiotic functions and the ability to form biofilm. The aim of this study was to compare the similarities and differences in the probiotic and physiological traits of L. plantarum Y42 in the biofilm and planktonic states. L. plantarum Y42 in the biofilm state was proven to have higher survival after passing through mimic gastrointestinal fluid, as well as excellent adhesion properties on the HT-29 cell monolayers, than those in the planktonic state. The expression of tight junction proteins (TJ proteins) of HT-29 cell monolayers treated by L. plantarum Y42 in the planktonic state increased, while similar changes were not observed in the HT-29 cells treated by the strain in the biofilm state. Furthermore, Balb/c mice were orally administered L. plantarum Y42 in the biofilm and planktonic states, respectively. Compared to the planktonic state, the oral administration of L. plantarum Y42 in the biofilm state significantly boosted IgA levels and improved the immunity of the mice. High-throughput sequencing showed that the diversity and structure of the intestinal flora of the mice were changed after the oral administration of L. plantarum Y42, including the up-regulated relative abundance of Lactobacillus in the intestinal tract of the mice, with no difference between the biofilm and planktonic states. Moreover, oral administration of L. plantarum Y42 in biofilm and planktonic states reduced the release of proinflammatory factors, to a certain extent, in the serum of the mice. The similarities and differences in the probiotic and physiological properties of L. plantarum Y42 in the biofilm and planktonic states can be contributed to the reasonable application of the strain.

Glycyrrhetinic acid reverses antibiotic-induced intestinal epithelial injury through RNA-binding protein human antigen R (HuR)

BACKGROUND

The application/abuse of antibiotics can cause antibiotic-induced intestinal injury (AIJ), a typical clinical issue that disturbs intestinal homeostasis. However, the underlying post-transcriptional mechanism of AIJ remains unknown. Glycyrrhetinic acid (GA) is one of the main components of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Batalin (Fabaceae), and findings of our previous study showed that GA can maintain intestinal homeostasis post-transcriptionally through the RNA-binding protein human antigen R (HuR).

PURPOSE

This study aimed to elucidate the role of HuR in AIJ and the protective effects of GA on AIJ.

STUDY DESIGN AND METHODS

Clindamycin hydrochloride was used to clarify the effect of the antibiotic on the intestinal epithelium. Intestinal epithelium cell-6 (IEC-6) and Caco2 cells were used to demonstrate the in vitro effects of the antibiotic and GA on intestinal cells. HuR plasmid and siRNA were used to overexpress or silence HuR in vitro. SD rats were induced by using clindamycin hydrochloride capsules (250 mg/kg i.g.) for 7 consecutive days to construct the in vivo AIJ model. Rats of the AIJ model group were administrated GA (10 and 20 mg/kg i.g.) for 7 days, and subsequently, the protective effect of GA on the intestinal epithelium was evaluated.

RESULTS

In vitro results showed that the antibiotic (150-500 μM) suppressed proliferation, induced a delay in restitution after wounding, and caused cell cycle arrest at the G0/G1 phase in IEC-6 and Caco-2 cells. Moreover, the expression levels of HuR and its downstream gene, occludin and cyclin D1, decreased after treatment with the antibiotic (500 μM). Overexpression of HuR and GA (10 and 20 μM) reversed the antibiotic-induced inhibition of proliferation and G0/G1 phase arrest, and the antibiotic-induced decrease in HuR, occludin, and cyclin D1 expression was reversed after GA treatment (10 and 20 μM) in IEC-6 cells. In vivo results revealed the antibiotic-induced epithelial injury of both the small intestines (shortened and spared mucosa) and the large intestines (injured/deformed glands, reduced number of cup cells, and evident inflammatory cell infiltration), all of which were ameliorated after GA treatment (10 and 20 μM).

CONCLUSION

Antibiotics induce intestinal epithelial injury through HuR, and GA can exert a protective effect on AIJ by restoring HuR levels.

A Scoring System Based on Nutritional and Inflammatory Parameters to Predict the Efficacy of First-Line Chemotherapy and Survival Outcomes for De Novo Metastatic Nasopharyngeal Carcinoma

PURPOSE

We aimed to develop a simple scoring system based on baseline inflammatory and nutritional parameters to predict the efficacy of first-line chemotherapy and survival outcomes for de novo metastatic nasopharyngeal carcinoma (mNPC).

PATIENTS AND METHODS

We retrospectively collected ten candidate inflammatory and nutritional parameters from de novo mNPC patients who received platinum-based first-line chemotherapy treatment. We examined the effects of these ten candidate variables on progression-free survival (PFS) using the Cox regression model. We built a risk-scoring system based on the regression coefficients associated with the identified independent prognostic factors. The predictive accuracy of the scoring system was evaluated and independently validated.

RESULTS

A total of 460 patients were analyzed. Four independent prognostic factors were identified in a training cohort and were used to construct the scoring system, including nutritional risk index, C-reactive protein level, alkaline phosphatase level, and lactate dehydrogenase level. Based on the score obtained from the scoring system, we stratified patients into three prognostic subgroups (low: 0-1 point, intermediate: 2-3 points, and high: 4 points) associated with significantly different disease control rates (94.7% vs. 92.5% vs. 66.0%, respectively) and survival outcomes (3-year PFS: 55.8% vs. 29.1% vs. 11.9%, respectively). The scoring system had a good performance for the prediction of short-term disease control (area under the receiver operating characteristic curve [AUC]: 0.701) and long-term survival outcomes (time-dependent AUC for 5-year PFS: 0.713). The results were internally validated using an independent cohort (AUC for predicting disease control: 0.697; time-dependent AUC for 5-year PFS: 0.713).

CONCLUSION

We developed and validated a clinically useful risk-scoring system that could predict the efficacy of first-line chemotherapy and survival outcomes in de novo mNPC patients. This system may help clinicians to design personalized treatment strategies.