Project description:Innate lymphoid cells (ILCs) can promote host defense, chronic inflammation or tissue protection and are regulated by cytokines and neuropeptides. However, their regulation by diet and microbiota-derived signals remains unclear. We show that an inulin fiber diet promotes Tph1-expressing inflammatory ILC2s (ILC2INFLAM) in the colon which produce IL-5 but not tissue-protective amphiregulin (AREG), resulting in accumulation of eosinophils. This exacerbates inflammation in a murine model of intestinal damage and inflammation in an ILC2- and eosinophil-dependent manner. Mechanistically, inulin fiber diet elevated microbiota-derived bile acids, including cholic acid (CA) that induced expression of ILC2-activating IL-33. In IBD patients, bile acids, their receptor farnesoid X receptor (FXR), IL-33, and eosinophils were all upregulated compared to controls, suggesting relevance of this diet-ILC2 axis in human IBD pathogenesis. Together, these data reveal that dietary fiber-induced changes in microbial metabolites operate as a rheostat that governs protective versus pathologic ILC2 responses with relevance to precision nutrition for inflammatory diseases.
Project description:Whole transcriptome analysis of genes expressed by spleen basophils in response to gasttrointestinal helminth infection, compared to naïve animals, analyzing the role of basophil-intrinsic Notch signaling using a basophil specific inhibition of Notch (Mcpt8Cre-DNMAML)
Project description:Innate lymphoid cells (ILCs) can promote host defense, chronic inflammation or tissue protection and are regulated by cytokines and neuropeptides. However, their regulation by diet and microbiota-derived signals remains unclear. We show that an inulin fiber diet promotes Tph1-expressing inflammatory ILC2s (ILC2INFLAM) in the colon which produce IL-5 but not tissue-protective amphiregulin (AREG), resulting in accumulation of eosinophils. This exacerbates inflammation in a murine model of intestinal damage and inflammation in an ILC2- and eosinophil-dependent manner. Mechanistically, inulin fiber diet elevated microbiota-derived bile acids, including cholic acid (CA) that induced expression of ILC2-activating IL-33. In IBD patients, bile acids, their receptor farnesoid X receptor (FXR), IL-33, and eosinophils were all upregulated compared to controls, suggesting relevance of this diet-ILC2 axis in human IBD pathogenesis. Together, these data reveal that dietary fiber-induced changes in microbial metabolites operate as a rheostat that governs protective versus pathologic ILC2 responses with relevance to precision nutrition for inflammatory diseases.
Project description:The majority of experiments investigating the immune response to gastrointestinal helminth infection use a single bolus infection. However, in situ individuals are repeatedly infected with low doses. Therefore, to model natural infection, mice were repeatedly infected (trickle infection) with low doses of Trichuris muris. Trickle infection resulted in the slow acquisition of immunity reflected by a gradual increase in worm burden followed by partial expulsion. Flow cytometry revealed that the CD4+ T cell response shifted from Th1 dominated to Th2 dominated, which coincided with an increase in Type 2 cytokines. The development of resistance following trickle infection was associated with increased worm expulsion effector mechanisms including goblet cell hyperplasia, Muc5ac production and increased epithelial cell turn over. Depletion of CD4+ T cells reversed resistance confirming their importance in protective immunity following trickle infection. In contrast, depletion of group 2 innate lymphoid cells did not alter protective immunity. T. muris trickle infection resulted in a dysbiotic mircrobiota which began to recover alpha diversity following the development of resistance. These data establish trickle infection as a robust and informative model for analysis of immunity to chronic intestinal helminth infection more akin to that observed under natural infection conditions and confirms the importance of CD4+ T cell adaptive immunity in host protection.
Project description:To assess the utility of diet modulation as a promising avenue to modulate ferroptosis in the colon, we examined the combinatorial effect of n-3 vs. n-6 polyunsaturated fatty acids (PUFA) and highly fermentable vs. poorly fermentable fiber on ferroptosis induction in preclinical models and healthy human adults. In vitro treatment of immortalized mouse colonocytes with docosahexaenoic acid, a n-3 PUFA enriched in fish oil, and butyrate, a short chain fatty acid generated by colonic microbial fermentation of fiber, reduced cell viability and interactively (P < 0.05) increased lipid peroxidation, a key biomarker for ferroptosis, compared to counterpart treatments. Addition of the ferroptosis inhibitor, ferrostatin-1, significantly blocked the combined effects of docosahexaenoic acid and butyrate on colonocyte lipid oxidation and cell death in vitro. In vivo treatment of mice fed fish oil and highly fermentable fiber (pectin) vs. control, corn oil (contains n-6 PUFA) and poorly fermentable fiber (cellulose) significantly (P < 0.05) promoted lipid peroxidation and the induction of ferroptosis transcriptional networks exclusively in colonic epithelial cells. In addition, as part of a randomized controlled crossover pilot study in humans, supplemental fermentable fiber (35 g/d soluble corn fiber) and fish oil (6 g/d n-3 PUFA) upregulated intestinal ferroptosis related gene expression, as compared to similar doses of maltodextrin plus corn oil. Our findings demonstrate that dietary fish oil and fermentable fiber act synergistically to induce ferroptosis in colonocytes. These important and often overlooked interactions between diet and the gut microbiome help to explain the anti-cancer benefit of the pesco-vegetarian diet.
Project description:To assess the utility of diet modulation as a promising avenue to modulate ferroptosis in the colon, we examined the combinatorial effect of n-3 vs. n-6 polyunsaturated fatty acids (PUFA) and highly fermentable vs. poorly fermentable fiber on ferroptosis induction in preclinical models and healthy human adults. In vitro treatment of immortalized mouse colonocytes with docosahexaenoic acid, a n-3 PUFA enriched in fish oil, and butyrate, a short chain fatty acid generated by colonic microbial fermentation of fiber, reduced cell viability and interactively (P < 0.05) increased lipid peroxidation, a key biomarker for ferroptosis, compared to counterpart treatments. Addition of the ferroptosis inhibitor, ferrostatin-1, significantly blocked the combined effects of docosahexaenoic acid and butyrate on colonocyte lipid oxidation and cell death in vitro. In vivo treatment of mice fed fish oil and highly fermentable fiber (pectin) vs. control, corn oil (contains n-6 PUFA) and poorly fermentable fiber (cellulose) significantly (P < 0.05) promoted lipid peroxidation and the induction of ferroptosis transcriptional networks exclusively in colonic epithelial cells. In addition, as part of a randomized controlled crossover pilot study in humans, supplemental fermentable fiber (35 g/d soluble corn fiber) and fish oil (6 g/d n-3 PUFA) upregulated intestinal ferroptosis related gene expression, as compared to similar doses of maltodextrin plus corn oil. Our findings demonstrate that dietary fish oil and fermentable fiber act synergistically to induce ferroptosis in colonocytes. These important and often overlooked interactions between diet and the gut microbiome help to explain the anti-cancer benefit of the pesco-vegetarian diet.
Project description:The intestine is a site of diverse functions including digestion, nutrient absorption, immune surveillance, and microbial symbiosis. As such, intestinal homeostasis is vital for overall wellbeing. Faecal microRNAs (miRNAs) offer valuable non-invasive insights into the transcriptional state of the intestine. However, typical faecal miRNA yields and profiles remain incompletely characterised. Here, we develop an optimised protocol for faecal miRNA detection, and describe a reproducible murine faecal miRNA profile across several studies by performing a meta-analysis. By examining faecal miRNA changes during chronic infection with the gastrointestinal helminth, Trichuris muris, we identify the altered expression of miRNAs associated with fibrosis, barrier integrity and wound healing. Fibrosis was confirmed in vivo, suggesting a role for these miRNAs in regulating wound healing during chronic infection where the production of classical wound healing Th2 cytokines are low. Further implementations of this technique can identify novel hypotheses and therapeutic strategies in diverse disease contexts.
Project description:Trichuris muris is very closely related to the human parasite T. trichiura sharing cross reactive antigens. Moreover, it is a remarkably tractable model system for dissecting immune responses and host parasite relationships and is actively being investigated in a number of laboratories worldwide. T. muris is a naturally occurring nematode parasite of mice which resides in the caecum and colon and has a direct oral faecal life cycle. High-throughput sequencing of Trichuris muris transcriptome for de novo assembly of transcripts. The main objective of this project is to recognize genes expressed in given life stages. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
Project description:Oxylipins derived from dietary polyunsaturated fatty acids (PUFAs) are key determinants of intestinal health, homeostasis and inflammatory disorders, such as colitis-associated colorectal cancer (CAC). Previous research has independently linked a high dietary omega (ω)-6:ω-3 PUFA ratio, or intestinal helminth infection, to an increased risk of CAC. However, whether these two factors interact to exacerbate disease risk and whether oxylipins contribute to this is unknown. In this study, we report that infection with the helminth Heligmosomoides polygyrus bakeri (Hpb) exacerbates tumour formation when combined with a high ω-6:ω-3 PUFA ratio diet. Dietary increases in tumour burden correlated with heightened levels of arachidonic acid (AA) and AA-derived lipoxygenase (LOX) oxylipins in the colon, including the 12/15-LOX product 12-hydroxyeicosatetraenoic acid, prior to disease onset. Although helminth infection further increased the production of 12/15-LOX oxylipins and increased expression of Alox15, responsible for producing these metabolites, inhibition of cyclooxygenase-dependent prostaglandin production with aspirin prevented helminth-exacerbation of disease. Helminth-infected mice exhibited increased phosphorylation of β-catenin in the colon, which was inhibited by EP2 and 4 antagonists. Moreover, administration of an EP agonist increased tumour burden in naive mice fed a high w-6:w-3 PUFA ratio diet, to the levels seen in helminth-exacerbation of disease. These data suggest that dietary changes in fatty acid composition coordinate with helminth-induced activation of EP signalling to exacerbate tumour development.