Browsing by Subject "Phenols"

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    A gut-derived metabolite alters brain activity and anxiety behaviour in mice
    (Springer Nature, 2022) Needham, Brittany D.; Funabashi, Masanori; Adame, Mark D.; Wang, Zhuo; Boktor, Joseph C.; Haney, Jillian; Wu, Wei-Li; Rabut, Claire; Ladinsky, Mark S.; Hwang, Son-Jong; Guo, Yumei; Zhu, Qiyun; Griffiths, Jessica A.; Knight, Rob; Bjorkman, Pamela J.; Shapiro, Mikhail G.; Geschwind, Daniel H.; Holschneider, Daniel P.; Fischbach, Michael A.; Mazmanian, Sarkis K.; Anatomy, Cell Biology and Physiology, School of Medicine
    Integration of sensory and molecular inputs from the environment shapes animal behaviour. A major site of exposure to environmental molecules is the gastrointestinal tract, in which dietary components are chemically transformed by the microbiota1 and gut-derived metabolites are disseminated to all organs, including the brain2. In mice, the gut microbiota impacts behaviour3, modulates neurotransmitter production in the gut and brain4,5, and influences brain development and myelination patterns6,7. The mechanisms that mediate the gut-brain interactions remain poorly defined, although they broadly involve humoral or neuronal connections. We previously reported that the levels of the microbial metabolite 4-ethylphenyl sulfate (4EPS) were increased in a mouse model of atypical neurodevelopment8. Here we identified biosynthetic genes from the gut microbiome that mediate the conversion of dietary tyrosine to 4-ethylphenol (4EP), and bioengineered gut bacteria to selectively produce 4EPS in mice. 4EPS entered the brain and was associated with changes in region-specific activity and functional connectivity. Gene expression signatures revealed altered oligodendrocyte function in the brain, and 4EPS impaired oligodendrocyte maturation in mice and decreased oligodendrocyte-neuron interactions in ex vivo brain cultures. Mice colonized with 4EP-producing bacteria exhibited reduced myelination of neuronal axons. Altered myelination dynamics in the brain have been associated with behavioural outcomes7,9-14. Accordingly, we observed that mice exposed to 4EPS displayed anxiety-like behaviours, and pharmacological treatments that promote oligodendrocyte differentiation prevented the behavioural effects of 4EPS. These findings reveal that a gut-derived molecule influences complex behaviours in mice through effects on oligodendrocyte function and myelin patterning in the brain.
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    Bisphenol A, Obesity, and Type 2 Diabetes Mellitus: Genuine Concern or Unnecessary Preoccupation?
    (Elsevier, 2014-07) Mirmira, Priyadarshini; Evans-Molina, Carmella; Department of Medicine, IU School of Medicine
    Bisphenol A or BPA is a ubiquitious industrial chemical found in a variety of plastic containers intended for food storage and in the epoxy resin linings of metal food and beverage cans, where it is used to prevent corrosion, food contamination, and spoilage. BPA has been recently linked to a wide variety of medical disorders and is known to have estrogenic activity with genomic as well as non-genomic estrogen-receptor mediated effects. Given rapidly increasing prevalence rates of metabolic disorders like obesity and Type 2 diabetes, BPA has recently come under intense scrutiny in scientific and lay communities as a potential endocrine disrupting compound with diabetogenic effects. The purpose of this review is to critically examine available literature investigating the link between BPA and alterations in metabolic health. Here, we discuss typical levels of exposure to BPA in daily life and analyze both epidemiological human data and mechanistic preclinical studies that have tested associations between BPA and obesity and diabetes. Finally, we summarize the current policies and views of national and international regulatory agencies regarding the safety of BPA use.