Project description:Alternative stable states in the intestinal ecosystem: proof of concept in a rat model and a perspective of therapeutic implications
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.
Project description:Opioid analgesics are frequently prescribed in the United States and worldwide. However, serious side effects such as addiction, immunosuppression and gastrointestinal symptoms limit long term use. In the current study using a chronic morphine-murine model a longitudinal approach was undertaken to investigate the role of morphine modulation of gut microbiome as a mechanism contributing to the negative consequences associated with opioids use. The results revealed a significant shift in the gut microbiome and metabolome within 24 hours following morphine treatment when compared to placebo. Morphine induced gut microbial dysbiosis exhibited distinct characteristic signatures profiles including significant increase in communities associated with pathogenic function, decrease in communities associated with stress tolerance. Collectively, these results reveal opioids-induced distinct alteration of gut microbiome, may contribute to opioids-induced pathogenesis. Therapeutics directed at these targets may prolong the efficacy long term opioid use with fewer side effects.
Project description:An alternative to the animal model to address the microbiome-host molecular interactions. We describe the development and applicability of 3D microfluidic devices equipped with a peristaltic-like movement to enhance the robustness and to address the interspecies differences that may reduce the major roadblock to therapeutic implementations.
Project description:A human gut-on-a-chip microdevice was used to coculture multiple commensal microbes in contact with living human intestinal epithelial cells for more than a week in vitro and to analyze how gut microbiome, inflammatory cells, and peristalsis-associated mechanical deformations independently contribute to intestinal bacterial overgrowth and inflammation. This in vitro model replicated results from past animal and human studies, including demonstration that probiotic and antibiotic therapies can suppress villus injury induced by pathogenic bacteria. By ceasing peristalsis-like motions while maintaining luminal flow, lack of epithelial deformation was shown to trigger bacterial overgrowth similar to that observed in patients with ileus and inflammatory bowel disease. Analysis of intestinal inflammation on-chip revealed that immune cells and lipopolysaccharide endotoxin together stimulate epithelial cells to produce four proinflammatory cytokines (IL-8, IL-6, IL-1β, and TNF-α) that are necessary and sufficient to induce villus injury and compromise intestinal barrier function. Thus, this human gut-on-a-chip can be used to analyze contributions of microbiome to intestinal pathophysiology and dissect disease mechanisms in a controlled manner that is not possible using existing in vitro systems or animal models. 6 samples, 2 biological replicates for each 3 conditions.
Project description:Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Using a mouse model mimicking pediatric antibiotic use, we found that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide altered both host and microbiota development. Early-life PAT accelerated total mass and bone growth, and resulted in progressive changes in gut microbiome diversity, population structure, and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. While control microbiota rapidly adapted to a change in diet, PAT slowed the ecological progression, with delays lasting several months in response to the macrolide. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment. C57BL/6J mice received three antibiotic courses: at days 10-15, 28-31, and 37-40 of life, amoxicillin or tylosin.Livers were collected at age 22 weeks, RNA was extracted, and transcriptional differences were measured by microarray analysis.
Project description:Cognitive impairment (CI) is a prevalent neurological condition characterized deficient attention, causal reasoning, learning and/or memory. Many genetic and environmental factors increase risk for CI, and the gut microbiome is increasingly implicated. However, the identity of gut microbes associated with CI risk, their effects on CI, and their mechanisms of action remain unclear. Here we examine the gut microbiome in response to restricted diet and intermittent hypoxia, known environmental risk factors for CI. Modeling the environmental factors together in mice potentiates CI and alters the gut microbiota. Depleting the microbiome by antibiotic treatment or germ-free rearing prevents the adverse effects of environmental risk on CI, whereas transplantation of the risk-associated microbiome into naïve mice confers CI. Parallel sequencing and gnotobiotic approaches identify the pathobiont Bilophila wadsworthia as enriched by the environmental risk factors for CI and as sufficient to induce CI. Consistent with CI-related behavioral abnormalities, B. wadsworthia and the risk-associated microbiome disrupt hippocampal activity, neurogenesis and gene expression. The CI induced by B. wadsworthia and by environmental risk factors is associated with microbiome-dependent increases in intestinal IFNy-producing Th1 cells. Inhibiting Th1 cells abrogates the adverse effects of both B. wadsworthia and environmental risk factors on CI. Together, these findings identify select gut bacteria that contribute to environmental risk for CI in mice by promoting inflammation and hippocampal dysfunction.
Project description:<p>This project explores the nature of the human intestinal microbiome in healthy children and children with recurrent abdominal pain. The overall goal is to obtain a robust knowledge-base of the intestinal microbiome in children without evidence of pain or gastrointestinal disease, children with functional abdominal pain, and children with abdominal pain and changes in bowel habits (irritable bowel syndrome). Multiple strategies have been deployed to navigate and understand the nature of the intestinal microbiome in childhood. These strategies include 454 pyrosequencing-based strategies to sequence 16S rRNA genes and understand the detailed composition of microbes in healthy and disease groups. Microarray-based hybridization with the PhyloChip and quantitative real-time PCR (qPCR) probes are being applied as complementary strategies to gain an understanding of the intestinal microbiome from various perspectives. Data collected and analyzed during the HMP UH2 and UH3 Demo project, from a set of healthy and IBS children may enable the identification of core microbiomes in children in addition to variable components that may distinguish healthy from diseased pediatric states. We are currently analyzing the dataset for the presence of disease-specific signatures in the human microbiome, and correlating these microbial signatures with pediatric health or IBS disease status. This study explores the nature of core and variable human microbiomes in pre-adolescent healthy children and children with recurrent abdominal pain.</p>