Effect of gut flora mediated-bile acid metabolism on intestinal immune microenvironment

Synbiotics containing sea buckthorn polysaccharides ameliorate DSS-induced colitis in mice via regulating Th17/Treg homeostasis through intestinal microbiota and their production of BA metabolites and SCFAs

Inflammatory Bowel Disease (IBD) is a chronic condition whose incidence has been rising globally. Synbiotic (SYN) is an effective means of preventing IBD. This study investigated the preventive effects and potential biological mechanisms of SYN (Bifidobacterium longum, Lactobacillus acidophilus, and sea buckthorn polysaccharides) on DSS-induced colitis in mice. The results indicated that dietary supplementation with SYN has a significant improvement effect on DSS mice. SYN ameliorated disease activity index (DAI), colon length, and intestinal barrier permeability in mice. In addition, RT-qPCR results indicated that after SYN intervention, the expression levels of pro-inflammatory factors (IL-6, IL-1β, TNF-α, and IL-17F) and transcription factor RORγt secreted by Th17 cells were significantly reduced, and the expression levels of anti-inflammatory factors (IL-10 and TGF-β) and transcription factor Foxp3 secreted by Treg cells were robustly increased. 16S rDNA sequencing analysis revealed that key intestinal microbiota related to Th17/Treg balance (Ligilactobacillus, Lactobacillus, Bacteroides, and Akkermansia) was significantly enriched. At the same time, a significant increase in microbial metabolites SCFAs and BAs was observed. We speculate that SYN may regulate the Th17/Treg balance by restructuring the structure and composition of the intestinal microbiota, thereby mitigating DSS-induced colitis.

High temperature aggravated hypoxia-induced intestine toxicity on juvenile Chinese mitten crab (Eriocheir sinensis)

High temperature and hypoxia in water due to global warming threaten the growth and development of aquatic animals. In natural or cultured environments, stress usually does not occur independently, whereas the synergistic effect of high temperature and hypoxia on Chinese mitten crab (Eriocheir sinensis) are rarely reported. In this study, 450 juvenile crabs were equally divided into control group (24 °C ± 0.5 °C, DO 6.8 ± 0.1 mg/L), hypoxia stress group (24 °C ± 0.5 °C, DO 1 ± 0.1 mg/L) and combined stress group (30 °C ± 0.5 °C, DO 1 ± 0.1 mg/L), and the intestinal health status, microbial diversity and metabolite profiles were evaluated for 24 h treatment. The results showed that hypoxia stress induced the expression level of pro-inflammatory related genes were significantly up-regulated in intestine of juvenile E. sinensis, and intestinal peritrophic membrane factor related genes were significantly down-regulated. High temperature further amplified the effects of hypoxia on pro-inflammatory and peritrophic membrane factor-related genes. Interesting, hypoxia stress induced a significant up-regulated of intestinal antioxidant-related genes, whereas high temperature reversed this trend. In addition, single stress or/and combined stress led to changes in intestinal microbiota diversity and abundance, and intestinal metabolite profiles. Compared with hypoxia stress, the synergistic effect of high temperature and hypoxia led to an increase in the abundance of pathogenic bacteria and a decrease in the abundance of probiotic bacteria. Moreover, intestinal metabolic pathways were significantly changed, especially amino acid metabolism and glycerophospholipid metabolism. Therefore, the results indicated that hypoxia stress could induce intestinal inflammatory response and oxidative stress, and lead to abnormal changes in intestinal microbiota and metabolic profiles, whereas high temperature further aggravate the toxic effects of hypoxia on the intestine. This study preliminarily revealed the synergistic toxic effects of high temperature and hypoxia on the intestine of juvenile E. sinensis.

Gut microbiota and metabolites as predictors of biologics response in inflammatory bowel disease: A comprehensive systematic review

Nonresponse to biologic agents in patients with inflammatory bowel disease (IBD) poses a significant public health burden, and the prediction of response to biologics offers valuable insights for IBD management. Given the pivotal role of gut microbiota and their endogenous metabolites in IBD, we conducted a systematic review to investigate the potential of fecal microbiota and mucosal microbiota and endogenous metabolomic markers as predictors for biotherapy response in IBD patients. A total of 38 studies were included in the review. Following anti-TNF-α treatment, the bacterial community characteristics of IBD patients exhibited a tendency to resemble those observed in healthy controls, indicating an improved clinical response. The levels of endogenous metabolites butyrate and deoxycholic acid were significantly associated with clinical remission following anti-TNF-α therapy. IBD patients who responded well to vedolizumab treatment had higher levels of specific bacteria that produce butyrate, along with increased levels of metabolites such as butyrate, branched-chain amino acids and acetamide following vedolizumab treatment. Crohn's disease patients who responded positively to ustekinumab treatment showed higher levels of Faecalibacterium and lower levels of Escherichia/Shigella. In conclusion, fecal microbiota and mucosal microbiota as well as their endogenous metabolites could provide a predictive tool for assessing the response of IBD patients to various biological agents and serve as a valuable reference for precise drug selection in clinical IBD patients.

The obeticholic acid can positively regulate the cancerous behavior of MCF7 breast cancer cell line

BACKGROUND

The diagnosis and treatment processes of cancer are among the main challenges of medical science in recent decades. The use of different therapeutic agents is one of the most common methods frequently utilized for cancer treatment. Accumulating evidence points to a potential effect of Obeticholic acid (OCA), a specific ligand for farnesoid X receptor, on the regulation of cancer-associated pathways. In spite of tremendous efforts to introduce OCA into the clinical setting, there is a great deal of uncertainty about its impact on breast cancer treatment. This study was performed to evaluate the effects of OCA on breast cancer.

METHODS AND RESULTS

In this experiment, the MCF-7 (Michigan Cancer Foundation-7) cell line was treated with 0.1 µM OCA, and cancerous characteristics of the MCF-7 cell line was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide) assay, gelatin zymography, western blot, Real-time PCR, flow cytometry, and ELISA techniques. The results indicated that OCA increased the rate of apoptosis and the expression levels of PPARα (Peroxisome proliferator-activated receptor alpha) and TIMP-1 (tissue inhibitor of metalloproteinase-1) genes in this cell line, while it reduced the mRNA levels of MMP7 (matrix metalloproteinase 7) and Bcl-2 (B-cell lymphoma 2) genes, as well as the protein levels of the active form of AKT (protein kinase B), Erk1/2 (extracellular signal-regulated kinase 1/2) and STAT3 (Signal transducers and activators of transcription-3). Also, OCA decreased the activity of MMP9, while it increased the secretion of VEGF-A (vascular endothelial growth factor-A).

CONCLUSIONS

It seems that OCA can exert anti-cancer effects on the MCF-7 cells by reducing growth, proliferation, migration, invasion, and regulation of the expression of genes involved in cancer-associated pathways. However, it should be noted that further studies are warranted to establish this concept, especially the increase of VEGF-A can be considered a challenge for the results of this study.

FXR Friend-ChIPs in the Enterohepatic System

Chronic liver diseases encompass a wide spectrum of hepatic maladies that often result in cholestasis or altered bile acid secretion and regulation. Incidence and cost of care for many chronic liver diseases are rising in the United States with few Food and Drug Administration-approved drugs available for patient treatment. Farnesoid X receptor (FXR) is the master regulator of bile acid homeostasis with an important role in lipid and glucose metabolism and inflammation. FXR has served as an attractive target for management of cholestasis and fibrosis; however, global FXR agonism results in adverse effects in liver disease patients, severely affecting quality of life. In this review, we highlight seminal studies and recent updates on the FXR proteome and identify gaps in knowledge that are essential for tissue-specific FXR modulation. In conclusion, one of the greatest unmet needs in the field is understanding the underlying mechanism of intestinal versus hepatic FXR function.