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:Methylmercury (MeHg) is a ubiquitous environmental toxicant that is often detected in the tissues of fish-eating species. It has been well established that prenatal exposure to MeHg can lead to widespread brain damage and impaired neurological development resulting in defects ranging from severe cerebral palsy and cognitive deficits to impaired motor and sensory function. A wide range of environmental toxicants have been shown to induce transgenerational inheritance of diseases via changes in DNA methylation—a well-known epigenetic modification. Our previous research has demonstrated that developmental MeHg exposure may yield transgenerational inheritance of neurological dysfunction in adult F3-lineage zebrafish via quantitative neurobehavioral assays that evaluated the visual startle response, retinal electrophysiology, and locomotor function. The objective of the current study was to examine the correlation between neurobehavioral phenotypes and the transcriptome activity in the brain and retina of F3 zebrafish by RNA sequencing (RNAseq). Transcriptomic analyses of F3 generation MeHg-treated zebrafish (compared to control) revealed significant gene dysregulation in both the brain and retina. There were 1648 and 138 differentially expressed genes in the retina and brain, respectively (FDR <0.05). Thirty-five genes were commonly dysregulated in both organs. Gene set enrichment analysis revealed significantly enriched pathways including: neurodevelopment, visual functions, phototransduction, and motor movement. Moreover, commonly dysregulated genes were associated with circadian rhythm and metabolic pathways, as well as arginine and proline metabolism. To our knowledge, this is the first evidence of a transgenerational transcriptome induced by ancestral developmental exposure to MeHg in any species. If the transgenerational phenotypes, transcriptome, homologous biomarkers, or similar molecular pathways hold true for human populations, our findings have significant impact on global public health in terms of identifying the susceptible populations using biomarkers and preventing transgenerational inheritance of MeHg-induced neurobehavioral deficits.

Dataset Information

Metagenomic sequencing of adult zebrafish feces after SMZ exposure (Exposure of Danio rerio to environmental sulfamethoxazole may contribute to neurobehavioral abnormalities via gut microbiome disturbance)

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