Wild-type and IL10-null mice have differential colonic epithelial gene expression responses to dietary supplementation with synbiotic Bifidobacterium animalis subspecies lactis and inulin

Prebiotics counteract the morphological and functional changes secondary to chronic cisplatin exposition in the proximal colon of mice

Cisplatin is an antimitotic drug able to cause acute and chronic gastrointestinal side effects. Acute side effects are attributable to mucositis while chronic ones are due to neuropathy. Cisplatin has also antibiotic properties inducing dysbiosis which enhances the inflammatory response, worsening local damage. Thus, a treatment aimed at protecting the microbiota could prevent or reduce the toxicity of chemotherapy. Furthermore, since a healthy microbiota enhances the effects of some chemotherapeutic drugs, prebiotics could also improve this drug effectiveness. We investigated whether chronic cisplatin administration determined morphological and functional alterations in mouse proximal colon and whether a diet enriched in prebiotics had protective effects. The results showed that cisplatin caused lack of weight gain, increase in kaolin intake, decrease in stool production and mucus secretion. Prebiotics prevented increases in kaolin intake, changes in stool production and mucus secretion, but had no effect on the lack of weight gain. Moreover, cisplatin determined a reduction in amplitude of spontaneous muscular contractions and of Connexin (Cx)43 expression in the interstitial cells of Cajal, changes that were partially prevented by prebiotics. In conclusion, the present study shows that daily administration of prebiotics, likely protecting the microbiota, prevents most of the colonic cisplatin-induced alterations.

Microbiota fermentation-NLRP3 axis shapes the impact of dietary fibres on intestinal inflammation

OBJECTIVE

Diets rich in fermentable fibres provide an array of health benefits; however, many patients with IBD report poor tolerance to fermentable fibre-rich foods. Intervention studies with dietary fibres in murine models of colonic inflammation have yielded conflicting results on whether fibres ameliorate or exacerbate IBD. Herein, we examined how replacing the insoluble fibre, cellulose, with the fermentable fibres, inulin or pectin, impacted murine colitis resulting from immune dysregulation via inhibition of interleukin (IL)-10 signalling and/or innate immune deficiency (Tlr5KO).

DESIGN

Mice were fed with diet containing either cellulose, inulin or pectin and subjected to weekly injections of an IL-10 receptor (αIL-10R) neutralising antibody. Colitis development was examined by serological, biochemical, histological and immunological parameters.

RESULTS

Inulin potentiated the severity of αIL10R-induced colitis, while pectin ameliorated the disease. Such exacerbation of colitis following inulin feeding was associated with enrichment of butyrate-producing bacteria and elevated levels of caecal butyrate. Blockade of butyrate production by either metronidazole or hops β-acids ameliorated colitis severity in inulin-fed mice, whereas augmenting caecal butyrate via tributyrin increased colitis severity in cellulose containing diet-fed mice. Elevated butyrate levels were associated with increased IL-1β activity, while inhibition of the NOD-like receptor protein 3 by genetic, pharmacologic or dietary means markedly reduced colitis.

CONCLUSION

These results not only support the notion that fermentable fibres have the potential to ameliorate colitis but also caution that, in some contexts, prebiotic fibres can lead to gut dysbiosis and surfeit colonic butyrate that might exacerbate IBD.

The effects of dietary Bacillus cereus QSI-1 on skin mucus proteins profile and immune response in Crucian Carp (Carassius auratus gibelio)

The objective of this study was to investigate the effect of dietary quorum quenching bacterium Bacillus cereus QSI-1 on skin mucus protein pattern and innate immune response in Crucian Carp (Carassius auratus gibelio). The differential proteomes of skin mucus of Crucian Carp were analyzed after administration of Bacillus cereus QSI-1 by isobaric tags for relative and absolute quantitation (iTRAQ) labeling, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 1974 proteins were quantified. Using a 1.5-fold change in expression as a physiological significant benchmark, 264 differentially expressed proteins were reliably quantified by iTRAQ analysis, including 130 up- and 134 down-regulated proteins after dietary Bacillus cereus QSI-1. Some Proteins that were involved in immunity included protein S100, annexin, histone H3, lymphocyte cytosolic protein 1, heat shock protein, L-plastin, keratin 91, etc. Furthermore, fish fed 5 × 10⁸ CFU/g Bacillus cereus QSI-1 supplemented diet showed an increase in alternative complement activity and lysozyme activity but expressed a decrease in superoxide dismutase activity in skin mucus (P < 0.05). However, administration of Bacillus cereus QSI-1 had no significant effects on total immunoglobulin level (P > 0.05). These results demonstrated that dietary administration of Bacillus cereus QSI-1 affects skin mucus protein profile and innate immune response in Crucian Carp, and also can enhance the disease resistance of Crucian Carp against A. hydrophila. This is the first report on proteomics analysis of skin mucus proteins in Crucian Carp after administration of quorum quenching bacterium Bacillus cereus, and the results will help to understand the mucosal immune responses to probiotics at the protein level in fish.

Defining Dysbiosis in Disorders of Movement and Motivation

The gut microbiota has emerged as a critical player in shaping and modulating brain function and has been shown to influence numerous behaviors, including anxiety and depression-like behaviors, sociability, and cognition. However, the effects of the gut microbiota on specific disorders associated with thalamo-cortico-basal ganglia circuits, ranging from compulsive behavior and addiction to altered sensation and motor output, are only recently being explored. Wholesale depletion and alteration of gut microbial communities in rodent models of disorders, such as Parkinson's disease, autism, and addiction, robustly affect movement and motivated behavior. A new frontier therefore lies in identifying specific microbial alterations that affect these behaviors and understanding the underlying mechanisms of action. Comparing alterations in gut microbiota across multiple basal-ganglia associated disease states allows for identification of common mechanistic pathways that may interact with distinct environmental and genetic risk factors to produce disease-specific outcomes.

Dietary or supplemental fermentable fiber intake reduces the presence of Clostridium XI in mouse intestinal microbiota: The importance of higher fecal bacterial load and density

OBJECTIVES

Clostridium difficile infection is a public health concern. C. difficile was found in healthy human intestine as a member of Clostridium XI. Because soluble fermentable fiber ingestion affects intestinal microbiota, we used fiber-containing diets to determine the intestinal microbial condition that could reduce the presence of Clostridium XI.

METHODS

Newly weaned male mice were assigned to three published diets: Control AIN-93G purified diet with only poorly fermented cellulose; Control plus 5% purified fermentable fiber inulin; Chow with wheat, soybean and corn that provide a mixture of unpurified dietary fibers. Methods were developed to quantify 24-hour fecal microbial load and microbial DNA density. The relative abundance of bacterial genera and the bacterial diversity were determined through 16S rRNA sequence-based fecal microbiota analysis.

RESULTS

Mice adjusted food intake to maintain the same energy intake and body weight under these three moderate-fat (7% w:w) diets. Chow-feeding led to higher food intake but also higher 24-h fecal output. Chow-feeding and 1-8 wk ingestion of inulin-supplemented diet increased daily fecal microbial load and density along with lowering the prevalence of Clostridium XI to undetectable. Clostridium XI remained undetectable until 4 weeks after the termination of inulin-supplemented diet. Fermentable fiber intake did not consistently increase probiotic genera such as Bifidobacterium or Lactobacillus. Chow feeding, but not inulin supplementation, increased the bacterial diversity.

CONCLUSIONS

Increase fecal microbial load/density upon fermentable fiber ingestion is associated with a lower and eventually undetectable presence of Clostridium XI. Higher bacterial diversity or abundance of particular genera is not apparently essential. Future studies are needed to see whether this observation can be translated into the reduction of C. difficile at the species level in at-risk populations.

Human and mouse microarrays-guided expression analysis of membrane protein trafficking-related genes in MDCK cells, a canine epithelial model for apical and basolateral differential protein targeting

MDCK cells are widely used to study the differential targeting of membrane transporters to apical and basolateral membrane but its canine origin limited the commercial tools available for the analysis of protein trafficking machinery. Because apical and basolateral membranes are only found in differentiated epithelial cells, genes critical for differential targeting may be specifically up-regulated upon MDCK cell differentiation. To search for these genes, a cross-species screening strategy was used. We first analyzed the human microarray data for protein trafficking-related genes that were up-regulated in colon carcinoma Caco2 cells upon differentiation. The results of mouse 44K gene expression microarray analysis were then used to extract additional candidate genes that showed higher expression in normal colon epithelium compared to primary embryonic fibroblasts. Finally, NCBI genomic sequence information was used to design RT-PCR primers for 13 candidate and 10 negative control genes and used to analyze MDCK cells at 2, 13 and 17 days after seeding. To determine whether the gene up-regulation was specific in epithelial differentiation, we also performed RT-PCR on rat non-differentiating intestinal IEC-6 cells and mouse C2C12 cells, a differentiating myoblast model. Of the 13 candidate genes, 3 genes, SDCBP2, KIF12, KIF27, met all criteria of specific up-regulation in differentiated MDCK cells. In addition, KIF13A showed up-regulation in differentiated MDCK and C2C12 cells but not in IEC-6 cells cultured for the same duration. The functions of these genes need to be analyzed in the future. This cross-species screening strategy may be useful for other non-human, non-rodent cell models.

Feed your gut with caution!

The intestinal epithelium, a single layer of cells organized into crypts and villi, is an important component of host defense against microbial community and its noxious metabolites. To preserve the epithelium integrity under constant exposure of intense physiological and environmental stressors, this surface is continuously and rapidly renewed by pluripotent intestinal epithelial stem cells that reside in the base of crypts. A recent study by Kaiko et al. shows that structural design of intestinal crypts protects the colonic epithelial stem/progenitor cells from proliferation-suppressing metabolites derived from the gut microbiota. Among these metabolites, butyrate is identified as the most potent inhibitor of colonic epithelial stem/progenitor cells proliferation. By rapidly metabolizing the butyrate, the colonocytes at the crypt further institute a metabolic barrier to protect the crypt-resident stem cells that fuel its renewal and repair.

Clostridium Butyricum CGMCC0313.1 Modulates Lipid Profile, Insulin Resistance and Colon Homeostasis in Obese Mice

Obesity is associated with a cluster of metabolic disorders and systemic low-grade inflammation involving multiple organs. Recent findings have suggested that intestine is a key organ altered in response to high fat diet (HFD) feeding. Probiotics mainly lactobacillus strains have earlier been implicated in alleviating metabolic disorders. Here we aimed to examine the effects of a naturally occurring butyrate-producing probiotic clostridium butyricum CGMCC0313.1 (CB0313.1) in limiting the development of HFD-induced obesity. Mice treated with CB0313.1 exhibited reduced lipid accumulation in liver and serum, lower circulating insulin levels and improved glucose tolerance and insulin sensitivity. Furthermore, CB0313.1 administration reversed the HFD-induced colonic inflammation as evidenced by reduced tumor necrosis factor (TNF)-α level and increases the interleukin (IL)-10 and IL-22 levels in colon tissue. Additionally to colonic inflammation, CB0313.1 also reduced the colon permeability by upregulating the tight junction (TJ) proteins (claudin-1 and occludin) and contributed to a decreased circulating endotoxin level. In colon content, CB0313.1 administration restored the reduced production of butyrate and other short chain fatty acids (SCFAs) caused by HFD feeding. In adipose tissue, lower transcriptional levels of pro-inflammatory TNF-α, IL-6, IL-1β and monocyte chemotactic protein (MCP)-1 in adipose tissue were observed in CB0313.1-treated mice. Collectively, our data demonstrated that CB0313.1, targeting colon inflammation and permeability, ameliorated HFD-induced obesity, insulin resistance as well as adipose inflammation.

A randomized, double-blind, placebo-controlled, clinical trial on probiotic soy milk and soy milk: effects on epigenetics and oxidative stress in patients with type II diabetes

This clinical trial aimed to discover the effects of probiotic soy milk and soy milk on MLH1 and MSH2 promoter methylation, and oxidative stress among type II diabetic patients. Forty patients with type II diabetes mellitus aged 35-68 years were assigned to two groups in this randomized, double-blind, controlled clinical trial. Patients in the intervention group consumed 200 ml/day of probiotic soy milk containing Lactobacillus plantarum A7, while those in the control group consumed 200 ml/d of conventional soy milk for 8 weeks. Fasting blood samples, anthropometric measurements, and 24-h dietary recalls were collected at the baseline and at the end of the study, respectively. Probiotic soy milk significantly decreased promoter methylation in proximal and distal MLH1 promoter region (P < 0.01 and P < 0.0001, respectively) compared with the baseline values, while plasma concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG) decreased significantly compared with soy milk (P < 0.05). In addition, a significant increase in superoxide dismutase (SOD) activity was observed in probiotic soy milk group compared with baseline value (P < 0.01). There were no significant changes from baseline in the promoter methylation of MSH2 within either group (P > 0.05). The consumption of probiotic soy milk improved antioxidant status in type II diabetic patients and may decrease promoter methylation among these patients, indicating that probiotic soy milk is a promising agent for diabetes management.

Quality of methods reporting in animal models of colitis

BACKGROUND

Current understanding of the onset of inflammatory bowel diseases relies heavily on data derived from animal models of colitis. However, the omission of information concerning the method used makes the interpretation of studies difficult or impossible. We assessed the current quality of methods reporting in 4 animal models of colitis that are used to inform clinical research into inflammatory bowel disease: dextran sulfate sodium, interleukin-10, CD45RB T cell transfer, and 2,4,6-trinitrobenzene sulfonic acid (TNBS).

METHODS

We performed a systematic review based on PRISMA guidelines, using a PubMed search (2000-2014) to obtain publications that used a microarray to describe gene expression in colitic tissue. Methods reporting quality was scored against a checklist of essential and desirable criteria.

RESULTS

Fifty-eight articles were identified and included in this review (29 dextran sulfate sodium, 15 interleukin-10, 5 T cell transfer, and 16 TNBS; some articles use more than 1 colitis model). A mean of 81.7% (SD = ±7.038) of criteria were reported across all models. Only 1 of the 58 articles reported all essential criteria on our checklist. Animal age, gender, housing conditions, and mortality/morbidity were all poorly reported.

CONCLUSIONS

Failure to include all essential criteria is a cause for concern; this failure can have large impact on the quality and replicability of published colitis experiments. We recommend adoption of our checklist as a requirement for publication to improve the quality, comparability, and standardization of colitis studies and will make interpretation and translation of data to human disease more reliable.