Dataset Information

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with Citrobacter rodentium According to the Vitamin A Status.

ABSTRACT: Vitamin A (VA) deficiency and diarrheal diseases are both serious public health issues worldwide. VA deficiency is associated with impaired intestinal barrier function and increased risk of mucosal infection-related mortality. The bioactive form of VA, retinoic acid, is a well-known regulator of mucosal integrity. Using Citrobacter rodentium-infected mice as a model for diarrheal diseases in humans, previous studies showed that VA-deficient (VAD) mice failed to clear C. rodentium as compared to their VA-sufficient (VAS) counterparts. However, the distinct intestinal gene responses that are dependent on the host's VA status still need to be discovered. The mRNAs extracted from the small intestine (SI) and the colon were sequenced and analyzed on three levels: differential gene expression, enrichment, and co-expression. C. rodentium infection interacted differentially with VA status to alter colon gene expression. Novel functional categories downregulated by this pathogen were identified, highlighted by genes related to the metabolism of VA, vitamin D, and ion transport, including improper upregulation of Cl^- secretion and disrupted HCO₃^- metabolism. Our results suggest that derangement of micronutrient metabolism and ion transport, together with the compromised immune responses in VAD hosts, may be responsible for the higher mortality to C. rodentium under conditions of inadequate VA.

SUBMITTER: Chai Z

PROVIDER: S-EPMC9026425 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with Citrobacter rodentium According to the Vitamin A Status.

Chai Zhi Z Lyu Yafei Y Chen Qiuyan Q Wei Cheng-Hsin CH Snyder Lindsay M LM Weaver Veronika V Sebastian Aswathy A Albert István I Li Qunhua Q Cantorna Margherita T MT Ross Catharine C

Nutrients 20220408 8

Vitamin A (VA) deficiency and diarrheal diseases are both serious public health issues worldwide. VA deficiency is associated with impaired intestinal barrier function and increased risk of mucosal infection-related mortality. The bioactive form of VA, retinoic acid, is a well-known regulator of mucosal integrity. Using Citrobacter rodentium-infected mice as a model for diarrheal diseases in humans, previous studies showed that VA-deficient (VAD) mice failed to clear C. rodentium a ...[more]

PMID: 35458125

Similar Datasets

Project description:The gut microbiota plays a crucial role in susceptibility to enteric pathogens, including Citrobacter rodentium, a model extracellular mouse pathogen that colonizes the colonic mucosa. C. rodentium infection outcomes vary between mouse strains, with C57BL/6 and C3H/HeN mice clearing and succumbing to the infection, respectively. Kanamycin (Kan) treatment at the peak of C57BL/6 mouse infection with Kan-resistant C. rodentium resulted in relocalization of the pathogen from the colonic mucosa and cecum to solely the cecal luminal contents; cessation of the Kan treatment resulted in rapid clearance of the pathogen. We now show that in C3H/HeN mice, following Kan-induced displacement of C. rodentium to the cecum, the pathogen stably colonizes the cecal lumens of 65% of the mice in the absence of continued antibiotic treatment, a phenomenon that we term antibiotic-induced bacterial commensalization (AIBC). AIBC C. rodentium was well tolerated by the host, which showed few signs of inflammation; passaged AIBC C. rodentium robustly infected naive C3H/HeN mice, suggesting that the AIBC state is transient and did not select for genetically avirulent C. rodentium mutants. Following withdrawal of antibiotic treatment, 35% of C3H/HeN mice were able to prevent C. rodentium commensalization in the gut lumen. These mice presented a bloom of a commensal species, Citrobacter amalonaticus, which inhibited the growth of C. rodentium in vitro in a contact-dependent manner and the luminal growth of AIBC C. rodentium in vivo. Overall, our data suggest that commensal species can confer colonization resistance to closely related pathogenic species. IMPORTANCE Gut bacterial infections involve three-way interactions between virulence factors, the host immune responses, and the microbiome. While the microbiome erects colonization resistance barriers, pathogens employ virulence factors to overcome them. Treating mice infected with kanamycin-resistant Citrobacter rodentium with kanamycin caused displacement of the pathogen from the colonic mucosa to the cecal lumen. Following withdrawal of the kanamycin treatment, 65% of the mice were persistently colonized by C. rodentium, which seemed to downregulate virulence factor expression. In this model of luminal gut colonization, 35% of mice were refractory to stable C. rodentium colonization, suggesting that their microbiotas were able to confer colonization resistance. We identify a commensal bacterium of the Citrobacter genus, C. amalonaticus, which inhibits C. rodentium growth in vitro and in vivo. These results show that the line separating commensal and pathogenic lifestyles is thin and multifactorial and that commensals may play a major role in combating enteric infection.

Project description:Overall hypothesis: RNAseq can be used to examine and compare the vitamin A (VA) effect, Infection effect caused by Citrobacter rodentium (C. rodentium), and the Interaction effect (VA status × C. rodentium infection) in mouse small intestine (SI) and colon, on the scale of global transcriptome. Methods: Vitamin A deficient (VAD) mice were generated by feeding VAD diet to the pregnant C57/BL6 dams and their post-weaning offspring. Vitamin A sufficient (VAS) mice were fed with purified diet containing normal amount of VA. At weaning, mice were maintained on their respective diets and assigned to one of the four treatment groups (non-infected VAD, infected VAD, non-infected VAS and infected VAS) until the end of the experiments. For the infected groups, age-matched VAD or VAS mice were orally inoculated with C. rodentium. Mice during early (SI study) or peak (colon study) C. rodentium infection were euthanized in two separate studies. The SI study focused on SI and analyses were performed on samples collected 5 days post-infection. The colon study analyzed samples on post-infection day 10, the peak of C. rodentium infection. Total mRNA extracted from SI and colon were sequenced using Illumina HiSeq 2500 platform. Three to six biological replicates were sequenced in each group. Differentially Expressed Gene (DEG), Gene Ontology (GO) enrichment, and Weighted Gene Co-expression Network Analysis (WGCNA) were performed to characterize expression patterns and co-expression patterns. Results: a) differentially expression genes (DEGs) corresponding to VA effect were present in both the SI and colon. In SI, DEGs altered by VA were mainly involved in the retinoid metabolic pathway and immunity-related pathways. Novel target genes (e.g. Mbl2, Mmp9, Cxcl14, and Nr0b2) and cell types (based on Tuft cell and mast cell markers) under the regulation of VA were suggested by differential expression analysis coupled with the co-expression network analysis. In regard to the colon, VA demonstrated an overall suppressive effect on the cell division pathway. Finally, the comparison of co-expression modules between SI and colon indicated distinct regulatory networks in these two organs. b) In the SI, no Infection effect was detected during early infection, whereas in the colon, during peak of C. rodentium infection: 1) It has been shown that infection upregulated innate and adaptive immune functions, epithelial proliferation, apoptosis, endoplasmic reticulum stress, and reactive oxygen species production, as well as downregulated ion and water absorption. This helped to confirm the findings in previous studies, consolidating the knowledge-base about the host response to C. rodentium, 2) Pathways (e.g. neuron activity, smooth muscle contraction, vascular constriction, and developmental regulation) and additional ion transporters previously not known to be influenced by C. rodentium were suggested as potential mechanisms responsible for the diarrhea pathology and host response. 3) Retinoic acid receptor (RAR) and vitamin D receptor (VDR) signaling pathways appeared to be downregulated by infection, indicating that the malabsorption of micronutrients might be a danger signal for the host to switch from homeostasis to an anti-infection mode. c) In the SI, no Interaction (VA status × C. rodentium infection) effect was detected during early infection. In colon, 1329 genes corresponded to the Interaction effect. During the peak of C. rodentium infection, the sufficient stimulation of cell division, protein catabolism, apoptosis, transcription regulation, MHC class I, interferons, and cytokine signaling might be of key importance for the resistance of VAS mice. In addition, the proper maintenance of the proliferation, differentiation, migration, and activation of T cells and leukocytes during peak infection may also confer the VAS hosts with higher survival and clearance rate. On the other hand, our data suggested that the higher rate of lethal dehydration observed in infected VAD mice, may be attributed to the disrupted of HCO3- metabolism and an improperly high level of Cl- secretion. Conclusions: VA alters the gene expression profile in both SI and colon, whereas the Infection effect and the Interaction effect were only observed in colon during peak of C. rodentium infection, but not in the SI during early infection. Our studies suggest novel target genes and cell types under the regulation of VA in the SI, and indicate that the resistance of the VAS hosts may be attributed to the concordant control over ion/water absorption, immune functions, as well as the balance between epithelial hyperplasia and apoptosis.

Project description:UnlabelledThe Gram-negative enteric bacterium Citrobacter rodentium is a natural mouse pathogen that has been extensively used as a surrogate model for studying the human pathogens enteropathogenic and enterohemorrhagic Escherichia coli. All three pathogens produce similar attaching and effacing (A/E) lesions in the intestinal epithelium. During infection, these bacteria employ surface structures called fimbriae to adhere and colonize the host intestinal epithelium. For C. rodentium, the roles of only a small number of its genome-carried fimbrial operons have been evaluated. Here, we report the identification of a novel C. rodentium colonization factor, called gut colonization fimbria (Gcf), which is encoded by a chaperone-usher fimbrial operon. A gcfA mutant shows a severe colonization defect within the first 10 days of infection. The gcf promoter is not active in C. rodentium under several in vitro growth conditions; however, it is readily expressed in a C. rodentium Δhns1 mutant lacking the closest ortholog of the Escherichia coli histone-like nucleoid structuring protein (H-NS) but not in mutants with deletion of the other four genes encoding H-NS homologs. H-NS binds to the regulatory region of gcf, further supporting its direct role as a repressor of the gcf promoter that starts transcription 158 bp upstream of the start codon of its first open reading frame. The gcf operon possesses interesting novel traits that open future opportunities to expand our knowledge of the structure, regulation, and function during infection of these important bacterial structures.ImportanceFimbriae are surface bacterial structures implicated in a variety of biological processes. Some have been shown to play a critical role during host colonization and thus in disease. Pathogenic bacteria possess the genetic information for an assortment of fimbriae, but their function and regulation and the interplay between them have not been studied in detail. This work provides new insights into the function and regulation of a novel fimbria called Gcf that is important for early establishment of a successful infection by C. rodentium in mice, despite being poorly expressed under in vitro growth conditions. This discovery offers an opportunity to better understand the individual role and the regulatory mechanisms controlling the expression of specific fimbrial operons that are critical during infection.

Project description:BackgroundVitamin B12 supplements typically contain doses that far exceed the recommended daily amount, and high exposures are generally considered safe. Competitive and syntrophic interactions for B12 exist between microbes in the gut. Yet, to what extent excessive levels contribute to the activities of the gut microbiota remains unclear. The objective of this study was to evaluate the effect of B12 on microbial ecology using a B12 supplemented mouse model with Citrobacter rodentium, a mouse-specific pathogen. Mice were fed a standard chow diet and received either water or water supplemented with B12 (cyanocobalamin: ~120 μg/day), which equates to approximately 25 mg in humans. Infection severity was determined by body weight, pathogen load, and histopathologic scoring. Host biomarkers of inflammation were assessed in the colon before and after the pathogen challenge.ResultsCyanocobalamin supplementation enhanced pathogen colonization at day 1 (P < 0.05) and day 3 (P < 0.01) postinfection. The impact of B12 on gut microbial communities, although minor, was distinct and attributed to the changes in the Lachnospiraceae populations and reduced alpha diversity. Cyanocobalamin treatment disrupted the activity of the low-abundance community members of the gut microbiota. It enhanced the amount of interleukin-12 p40 subunit protein (IL12/23p40; P < 0.001) and interleukin-17a (IL-17A; P < 0.05) in the colon of naïve mice. This immune phenotype was microbe dependent, and the response varied based on the baseline microbiota. The cecal metatranscriptome revealed that excessive cyanocobalamin decreased the expression of glucose utilizing genes by C. rodentium, a metabolic attribute previously associated with pathogen virulence.ConclusionsOral vitamin B12 supplementation promoted C. rodentium colonization in mice by altering the activities of the Lachnospiraceae populations in the gut. A lower abundance of select Lachnospiraceae species correlated to higher p40 subunit levels, while the detection of Parasutterella exacerbated inflammatory markers in the colon of naïve mice. The B12-induced change in gut ecology enhanced the ability of C. rodentium colonization by impacting key microbe-host interactions that help with pathogen exclusion. This research provides insight into how B12 impacts the gut microbiota and highlights potential consequences of disrupting microbial B12 competition/sharing through over-supplementation. Video Abstract.

Project description:Opioids analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit their use. It has been recently demonstrated that morphine treatment results in significant disruption in gut barrier function leading to increased translocation of gut commensal bacteria. Further study indicated distinct alterations in the gut microbiome and metabolome following morphine treatment, contributing to the negative consequences associated with opioid use. However, it is unclear how opioids modulate gut homeostasis in the context of a hospital acquired bacterial infection. In the current study, a mouse model of C. rodentium infection was used to investigate the role of morphine in the modulation of gut homeostasis in the context of a hospital acquired bacterial infection. Citrobacter rodentium is a natural mouse pathogen that models intestinal infection by enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) and causes attaching and effacing lesions and colonic hyperplasia. Morphine treatment resulted in 1) the promotion of C. rodentium systemic dissemination, 2) increase in virulence factors expression with C. rodentium colonization in intestinal contents, 3) altered gut microbiome, 4) damaged integrity of gut epithelial barrier function, 5) inhibition of C. rodentium-induced increase in goblet cells, and 6) dysregulated IL-17A immune response. This is the first study to demonstrate that morphine promotes pathogen dissemination in the context of intestinal C. rodentium infection, indicating morphine modulates virulence factor-mediated adhesion of pathogenic bacteria and induces disruption of mucosal host defense during C. rodentium intestinal infection in mice. This study demonstrates and further validates a positive correlation between opioid drug use/abuse and increased risk of infections, suggesting over-prescription of opioids may increase the risk in the emergence of pathogenic strains and should be used cautiously. Therapeutics directed at maintaining gut homeostasis during opioid use may reduce the comorbidities associated with opioid use for pain management.

Dataset Information

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with Citrobacter rodentium According to the Vitamin A Status.

Publications

Transcriptional Profiling of the Small Intestine and the Colon Reveals Modulation of Gut Infection with <i>Citrobacter rodentium</i> According to the Vitamin A Status.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets