A Fiber-Rich Diet and Radiation-Induced Injury in the Murine Intestinal Mucosa

Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific pro-inflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.

Colonic Mucosal Immune Activation in Mice with Ovalbumin-Induced Allergic Airway Disease: Association between Allergic Airway Disease and Irritable Bowel Syndrome

Recent studies on the pathophysiology of irritable bowel syndrome (IBS) have focused on the role of mast cells (MCs) in intestinal mucosal immunity. A link between allergic airway diseases (AADs) and IBS has been suggested because both diseases have similar pathophysiology. We aimed to investigate whether the induction of AAD in mice could lead to inflammation of the colonic mucosa, similar to IBS. We also evaluated whether this inflammatory response could be suppressed by administering a therapeutic agent. Mice were divided into three groups: control, AAD-induced, and salbutamol-treated. An AAD mouse model was established by intraperitoneal injection and nasal challenge with ovalbumin. Mice with AAD were intranasally administered salbutamol. Analyses of cytokine levels, MC count, and tryptase levels in the intestinal mucosa were performed to compare the changes in inflammatory responses among the three groups. Inflammation was observed in the intestinal mucosa of mice in the AAD group. This inflammation in AAD mice was suppressed after salbutamol treatment. Our study demonstrates that AAD induces an inflammatory response similar to that in IBS, suggesting a possible association between IBS and AADs. In patients with IBS with such allergic components, salbutamol may have the potential to alleviate the inflammatory response.

Using a ligate intestinal loop mouse model to investigate Clostridioides difficile adherence to the intestinal mucosa in aged mice

Interaction of Clostridioides difficile spores with the intestinal mucosa contributes to the persistence and recurrence of the infection. Advanced age is one of the main risk factors for C. difficile infection and recurrence of the disease. However, interaction of C. difficile spores with the intestinal mucosa during aging has not been evaluated. In the present work, using intestinal ligated loop technique in a mouse model, we analyzed C. difficile spore adherence and internalization to the ileum and colonic mucosa during aging. Additionally, we provide visual documentation of the critical steps of the procedure. Consequently, our data suggest that spore internalization in the ileum and colonic mucosa is higher in elderly mice rather than adults or young mice. Also, our data suggest that spore adherence to the ileum and colonic mucosa decreases with aging.

Nutritional Deficiencies in Celiac Disease: Current Perspectives

Gluten-induced T-cell-mediated immune response damages the villous structure that significantly affects the functioning of the small intestinal mucosa [...]

An Intramuscular Multivalent Vaccine Against Pathogenic Escherichia Coli Injected in Suckling Piglets Reduced the Prevalence of Pathogenic E. Coli and Lawsonia Intracellularis Until Slaughter

Background: The present study aims to evaluate the efficacy of an intramuscular multivalent Escherichia coli vaccine for suckling piglets against infection not only by pathogenic E. coli but also by pathogens involved in Porcine Enteric Disease Complex (PEDC). Vaccinated Group had piglets vaccinated at days 10 and 20 of life with Colidex-C® (Vetia Animal Health, Spain), and Control Group had piglets that received sterile saline solution injection at the same days of life. We collected fecal samples in the farm from animals presenting diarrhea and intestinal mucosa swabs and ileum and colon tissue at slaughter and then performed PCR to identify E. coli virulence factors genes. Furthermore, we performed PCR to identify Lawsonia intracellularis, Brachyspira hyodisenteriae, and Salmonella spp.Results: Regarding fecal samples, 0% from Vaccinated Group was positive for E. coli, while Control Group had 94.1% of positive samples (p<0.0001). With respect to intestinal mucosa swab, 0% of the samples from Vaccinated Group were positive for E. coli, while 100% from Control Group were positive (p=0.001). Regarding ileum and colon tissue samples, 35% were positive for E. coli in Vaccinated Group and 85% in Control Group (p=0.001); Gcnt had a higher frequency of F41 (p=0.018), LT (p=0.018) and Sta (p=0.028) virulence factors genes. No sample was positive for Salmonella spp. nor for B. hyodisenteriae, but there were positive samples L. intracellularis; real-time PCR was performed and the frequencies found were 40% and 20% of ileum and colon positive samples in Vaccinated Group and 100% for ileum and 70% for colon in Control Group (p<0.001 for ileum and p=0.001 for colon).Conclusion: The results indicate that the E. coli vaccine for piglets may be a strategy to control E. coli infection. E. coli vaccines emerge as a probable strategy to help control L. intracellularis and, maybe, other enteric pathogens of pigs not evaluated in this study.

GBP4 is an Accurate Diagnostic Biomarker and a Potential Treatment Target for Crohn’s Disease

Background: Extensive evidence has shown that immune cell infiltration is associated with the pathogenesis of Crohn’s disease (CD). In the present study, we explored the potential mechanism underlying the pathogenesis biomarkers for CD.Methods: The GSE179285 dataset containing sequence data for intestinal mucosal was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in the intestinal mucosa of CD patients and healthy individuals were then identified. The infiltration pattern of 22 immune cell types was assessed using the CIBERSORT algorithm. The DEGs and 22 immune cell types were combined to find the key gene network using weighted gene co-expression network analysis (WGCNA), and pathway enrichment analyzes were performed on the hub module in the WGCNA. A linear regression model for the relationship between the expression of the hub genes in CD patients and infiltration of immune cells were also developed. The utility and accuracy of the hub genes for CD diagnosis were assessed using receiver operating characteristic (ROC) analysis. The accuracy of the model was validated using GSE20881 dataset. Results: There were 1135 DEGs between the intestinal mucosal tissue of CD patients and healthy individuals. Of these DEGs, 711 genes were upregulated, whereas 424 of them were downregulated. There was also a significant difference in the infiltration of immune cells to the intestinal mucosal between the CD patients and healthy individuals. WGCNA revealed that the turquoise module genes were strongly correlated with the infiltration of M1 macrophages (cor=0.68, p=10-16). Pathway enrichment analysis further showed the genes in the turquoise module mainly regulated the secretion of interferon-gamma and other immune effector molecules. Finally, the expression of GBP4, the identified hub gene, strongly correlated with the infiltration of M1 macrophages (adjusted r-squared=0.661, p<2x10-16), and is a relatively good marker for CD diagnostic prediction (AUC=0.736). The relationship between GBP4 expression and infiltration of M1 macrophages (adjusted r-squared=0.435, p<2x10-16) and prognostic value of the gene (AUC=0.702) were verified using the GSE20881 validation dataset.Conclusion: GBP4 is a potential biomarker for accurate CD diagnosis. The expression of GBP4 promotes the infiltration of M1 macrophages to the intestinal mucosa of CD patients.

Hobit confers tissue-dependent programs to type 1 innate lymphoid cells

Identification of type 1 innate lymphoid cells (ILC1s) has been problematic. The transcription factor Hobit encoded by Zfp683 has been proposed as a major driver of ILC1 programs. Using Zfp683 reporter mice, we showed that correlation of Hobit expression with ILC1s is tissue- and context-dependent. In liver and intestinal mucosa, Zfp683 expression correlated well with ILC1s; in salivary glands, Zfp683 was coexpressed with the natural killer (NK) master transcription factors Eomes and TCF1 in a unique cell population, which we call ILC1-like NK cells; during viral infection, Zfp683 was induced in conventional NK cells of spleen and liver. The impact of Zfp683 deletion on ILC1s and NK cells was also multifaceted, including a marked decrease in granzyme- and interferon-gamma (IFNγ)–producing ILC1s in the liver, slightly fewer ILC1s and more Eomes+ TCF1+ ILC1-like NK cells in salivary glands, and only reduced production of granzyme B by ILC1 in the intestinal mucosa. NK cell–mediated control of viral infection was unaffected. We conclude that Hobit has two major impacts on ILC1s: It sustains liver ILC1 numbers, while promoting ILC1 functional maturation in other tissues by controlling TCF1, Eomes, and granzyme expression.

Identification of Pharmacological Autophagy Regulators of Active Ulcerative Colitis

Background: Ulcerative colitis (UC) is a chronic recurrent disease of unknown etiology. Recently, it has been reported that autophagy-related gene polymorphism is closely associated with increased risk of UC, and the therapeutic effect of some UC drugs is mediated by regulating autophagy pathways. This study aims to identify pivotal autophagy-related regulators in UC pathogenesis and provide novel molecular targets for the treatment of active UC.Methods: Gene expression profiles and clinical information of active UC patients were obtained from GEO databases. CIBERSORT was adopted to evaluate the immune cell infiltration. We used weighted gene co-expression network analysis (WGCNA) and differential expression analysis to identify the pivotal modules and genes associated with active UC. Subsequently, we conducted validation in the validation set and explored its relationship with commonly used UC therapeutics.Results: 36 healthy controls and 46 active UC patients have been obtained from the training set of GSE53306, GSE87466, and GSE134025. There were 423 differentially expressed genes (DEGs) found, which dramatically enriched in autophagy-related pathways. And more infiltration of mast cells, activated T cells, dendritic cells, and M1 macrophages were observed in the intestinal mucosa of active UC, while more infiltration of resting immune cells and M2 macrophages in healthy controls. WGCNA indicated that the turquoise and blue modules were the critical modules. CASP1, SERPINA1, and CCL2 have been identified as the hub autophagy-related genes of active UC, after combining DEGs and 232 autophagy-related genes from HADb with the genes of turquoise and blue modules, respectively. We further verified that CASP1, SERPINA1, and CCL2 were positively associated with active UC and served as an autophagy-related biomarker for active UC. Moreover, increased SERPINA1 in the involved intestinal mucosa was reduced in patients with active UC who responded to golimumab or glucocorticoid therapy. But, neither CASP1, SERPINA1, and CCL2 were changed by treatment of 5-aminosalicylic acid (5-ASA) and azathioprine.Conclusion: CASP1, SERPINA1, and CCL2 are autophagy-related hub genes of active UC. And SERPINA1 may serve as a new pharmacological autophagy regulator of UC, which provides a new target for the use of small molecules targeting autophagy in the treatment of active UC.