Publications by authors named "Renee L Greer"

The gut microbiota has been implicated as a major factor contributing to metabolic diseases and the response to drugs used for the treatment of such diseases. In this study, we tested the effect of cholestyramine, a bile acid sequestrant that reduces blood cholesterol, on the murine gut microbiota and metabolism. We also explored the hypothesis that some effects of this drug on systemic metabolism can be attributed to alterations in the gut microbiota.

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  • Microbiota from a high-fat/high-sugar diet contributes to type 2 diabetes by impairing mitochondrial function in white adipose tissue (WAT), impacting overall glucose metabolism.
  • *Mmp12+ macrophages are crucial in connecting microbiota-triggered inflammation with mitochondrial damage in WAT, which is linked to insulin resistance in obese individuals.
  • *Inhibiting MMP12 or having a genetic deficiency in Mmp12 improves glucose metabolism in regular mice, but not in germ-free mice, indicating that the effect is microbiota-dependent.
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  • Common variable immunodeficiency (CVID) can lead to a specific condition called CVID enteropathy (E-CVID), characterized by duodenal inflammation and malabsorption.
  • E-CVID patients show extremely low levels of IgA in their duodenal tissues compared to those without enteropathy, indicating a significant immunological abnormality.
  • The study also identified Acinetobacter baumannii as a potential harmful bacteria contributing to inflammation in E-CVID, which disrupts normal lipid metabolism in the intestines.
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  • The gut microbiome significantly influences health, and antibiotics are known to alter it, though their effects on glucose tolerance in lean mice remain underexplored.
  • In this study, researchers treated lean, normoglycemic mice with different antibiotics to evaluate changes in body weight, glucose metabolism, liver and ileum gene expression, and gut microbiota shifts.
  • Results showed that antibiotics reduced fasting glucose levels and altered glucose tolerance without affecting body weight, revealing potential interactions between the microbiome, gene expression, and glucose metabolism in a non-obese context.
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Background: Arsenic has antimicrobial properties at high doses yet few studies have examined its effect on gut microbiota. This warrants investigation since arsenic exposure increases the risk of many diseases in which gut microbiota have been shown to play a role. We examined the association between arsenic exposure from drinking water and the composition of intestinal microbiota in children exposed to low and high arsenic levels during prenatal development and early life.

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Cross-talk between the gut microbiota and the host immune system regulates host metabolism, and its dysregulation can cause metabolic disease. Here, we show that the gut microbe Akkermansia muciniphila can mediate negative effects of IFNγ on glucose tolerance. In IFNγ-deficient mice, A.

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Current approaches in human embryonic stem cell (hESC) to pancreatic beta cell differentiation have largely been based on knowledge gained from developmental studies of the epithelial pancreas, while the potential roles of other supporting tissue compartments have not been fully explored. One such tissue is the pancreatic mesenchyme that supports epithelial organogenesis throughout embryogenesis. We hypothesized that detailed characterization of the pancreatic mesenchyme might result in the identification of novel factors not used in current differentiation protocols.

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Objective: Despite widespread use of antibiotics for the treatment of life-threatening infections and for research on the role of commensal microbiota, our understanding of their effects on the host is still very limited.

Design: Using a popular mouse model of microbiota depletion by a cocktail of antibiotics, we analysed the effects of antibiotics by combining intestinal transcriptome together with metagenomic analysis of the gut microbiota. In order to identify specific microbes and microbial genes that influence the host phenotype in antibiotic-treated mice, we developed and applied analysis of the transkingdom network.

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The human gut is a unique organ in which hundreds of different microbial species find their habitat and in which different host physiologic functions, such as digestion, nutrition, and immunity, coexist. Although all these players were studied separately for decades, recently, there has been an explosion of studies demonstrating the essential role for interactions between these components in gut function. Furthermore, new systems biology methods provide essential tools to study this complex system as a whole and to identify key elements that define the crosstalk between the gut microbiota, immunity, and metabolism.

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Background & Aims: Pancreatic ductal adenocarcinoma (PDA) is a leading cause of cancer-related death. Through the process of acinar-to-ductal metaplasia (ADM), pancreatic acinar cells give rise to pancreatic intraepithelial neoplasia (PanIN), the most common precursor of PDA. However, even when Kras is activated in a majority of acinar cells, ADM and subsequent development of PanINs is inefficient in the absence of additional stresses.

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