Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer. We used microarrays to compare the transcriptome Aim2 deficent mice to wild type mice in colon tumor and colitis samples. Here were 12 mice in total, 3 for each genotype and tissue combination.
Project description:Colorectal cancer is a leading cause of cancer-related deaths. Mutations in the innate immune receptor AIM2 are frequently identified in patients with colorectal cancer, but how AIM2 modulates colonic tumorigenesis is unknown. Here, we found that Aim2-deficient mice were hypersusceptible to colonic tumor development. Production of inflammasome-associated cytokines and other inflammatory mediators were largely intact in Aim2-deficient mice, however, intestinal stem cells were prone to uncontrolled proliferation. Aberrant Wnt signaling expanded a population of tumor-initiating stem cells in the absence of AIM2. Susceptibility of Aim2-deficient mice to colorectal tumorigenesis was enhanced by a dysbiotic gut microbiota, which was reduced by reciprocal exchange of gut microbiota with wild-type healthy mice. These findings uncover a synergy between a specific host genetic factor and gut microbiota in determining the susceptibility to colorectal cancer. Therapeutic modulation of AIM2 expression and microbiota has the potential to prevent colorectal cancer.
Project description:Iron is an essential metal for both animals and microbiota, and neonates and infants of humans and animals, in general, are at the risk of iron insufficient. However, excess dietary iron usually causes negative impacts on the host and microbiota. This study aimed to investigate over-loaded dietary iron supplementation on growth performance, the distribution pattern of iron in the gut lumen and the host, intestinal microbiota, and intestine gene expression profile of piglets. Sixty healthy weaning piglets were randomly assigned to six groups: fed with diets supplemented with ferrous sulfate monohydrate at the dose of 50ppm (Fe50 group), 100ppm (Fe100 group), 200ppm (Fe200 group), 500ppm (Fe500 group), and 800ppm (Fe800) for three weeks. The results indicated that increasing iron had no effects on growth performance but increased diarrheal risk and iron deposition in intestinal digesta, tissues of intestine and liver, and serum. High iron also reduced serum iron-binding capacity, apolipoprotein, and immunoglobin A. The RNA-sequencing analysis revealed that iron changed colonic gene expression profile, such as interferon gamma-signal transducer and activator of transcription 2 based anti-virus and bacteria gene network. Increasing iron also shifted cecal and colonic microbiota, such as reducing alpha diversity, Clostridiales and Lactobacillus reuteri, and increasing Lactobacillus and Lactobacillus amylovorus. Collectively, this study demonstrated that high dietary iron increased diarrheal incidence, changed intestinal immune response-associated gene expression, and shifts gut microbiota. The results would enhance our knowledge of iron effects on the gut and microbiome in piglets, and further contribute to understanding these aspects in humans.
Project description:Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the development and quality of immune responses. However, the factors and mechanisms involved remain to be elucidated. Here, we demonstrate that DR-induced optimization of immunological memory requires co-operation between memory T cells, the intestinal microbiota, and myeloid cells. Our data indicate that DR enhances the ability of memory T cells to recruit and activate myeloid cells in the context of a secondary infection. Concomitantly, DR promotes expansion of the commensal Bifidobacteria within the large intestine, which supplies the short-chain fatty acid acetate to myeloid cells. Acetate conditioning of the myeloid compartment during DR enhances their capacity to kill pathogens. Enhanced host protection during DR is abolished when Bifidobacteria expansion is prevented, indicating that microbiota configuration and function critically dictates immune responsiveness to this dietary intervention. Altogether, DR induces both memory T cells and the gut microbiota to produce essential, distinct factors that converge on myeloid cells to promote optimal pathogen control. These findings reveal how nutritional cues promote adaptation and co-operation between multiple immune cells and the gut microbiota, which synergize to optimize immunity and protect the collective metaorganism.
Project description:Mild or transient dietary restriction (DR) improves many aspects of health and aging. Emerging evidence from us and others has demonstrated that DR also optimizes the development and quality of immune responses. However, the factors and mechanisms involved remain to be elucidated. Here, we demonstrate that DR-induced optimization of immunological memory requires co-operation between memory T cells, the intestinal microbiota, and myeloid cells. Our data indicate that DR enhances the ability of memory T cells to recruit and activate myeloid cells in the context of a secondary infection. Concomitantly, DR promotes expansion of the commensal Bifidobacteria within the large intestine, which supplies the short-chain fatty acid acetate to myeloid cells. Acetate conditioning of the myeloid compartment during DR enhances their capacity to kill pathogens. Enhanced host protection during DR is abolished when Bifidobacteria expansion is prevented, indicating that microbiota configuration and function critically dictates immune responsiveness to this dietary intervention. Altogether, DR induces both memory T cells and the gut microbiota to produce essential, distinct factors that converge on myeloid cells to promote optimal pathogen control. These findings reveal how nutritional cues promote adaptation and co-operation between multiple immune cells and the gut microbiota, which synergize to optimize immunity and protect the collective metaorganism.
Project description:We report that dietary iron protects mice from infection by Citrobacter rodentium. Iron induces a state of insulin resistance and increases glucose availability in the gut, thereby attenutating C. rodentium virulence. Additionally the pathogen appears to be driven towards a long-term commensal state. Here, we identify mutations in persistent and avirulent Citrobacter rodentium isolates from mice given an iron supplemented diet.
Project description:Purpose: Helminth infection and dietary intake can affect the intestinal microbiota, as well as the immune system. Methods: Here we analyzed the relationship between fecal microbiota and blood profiles of indigenous Malaysians, referred to locally as Orang Asli, in comparison to urban participants from the capital city of Malaysia, Kuala Lumpur. Results: We found that helminth infections had a larger effect on gut microbial composition than did dietary intake or blood profiles. Trichuris trichiura infection intensity also had the strongest association with blood transcriptional profiles. By characterizing paired longitudinal samples collected before and after deworming treatment, we determined that changes in serum zinc and iron levels among the Orang Asli were driven by changes in helminth infection status, independent of dietary metal intake. Serum zinc and iron levels were associated with changes in the abundance of several microbial taxa. Conclusions: There is considerable interplay between helminths, micronutrients and the microbiota on the regulation of immune responses in humans.
Project description:Our preliminary data suggest that differential gut microbiota modulates acetaminophen-induced hepatotoxicity (APAP toxicity) in mice model. The goal of our study is to determine whether commensal gut microbiota modulates the hepatic gene expressions potentially responsible for modulating APAP toxicity.
Project description:Dietary lipids and gut microbiota may both influence adipose tissue physiology. By feeding conventional and germ-free mice high fat diets with different lipid compositon we aimed to investigate how dietary lipids and the gut microbiota interact to influence inflammation and metabolism in the liver