Humanity is facing an epidemic of interrelated obesity-associated disorders including insulin-resistance, hyperlipidemia, hepatic steatosis and hypertension that are collectively referred to as metabolic syndrome. Pioneering work by Jeff Gordon and colleagues have demonstrated that a central component of metabolic syndrome, namely obesity, is influenced by the ability of an individual's intestinal microbiota to mediate energy harvest from ingested food. Our work, which this competitive renewal application seeks to sustain, has developed the hypothesis that gut microbiota plays a pivotal role in numerous aspects of metabolic syndrome primarily via driving low-grade inflammation. This hypothesis builds upon the inflammatory explanation for insulin resistance that seeks to explain the causal link between obesity and type 2 diabetes. However, our hypothesis holds that inflammation is not purely a consequence of obesity but, rather, alterations in gut microbiota drive low-grade inflammation that promote adiposity via driving lipogenesis and interfering with metabolic receptor signaling (e.g. insulin and leptin receptors). Work performed under this grant demonstrates that such alterations in microbiota composition can originate from a variety of underlying causes including an innate immune deficiency, timely presence of pathobiont bacteria, or select food additives. That altered microbiota are not merely a marker of inflammation but drive inflammation and metabolic syndrome in these mouse models is supported by our demonstration that transplanting them recapitulates the low-grade inflammation/metabolic syndrome phenotype in the recipients. While the specific microbial species whose abundance is altered differs depending upon mouse strain, vivarium, and underlying cause of low-grade inflammation, this project has revealed general functional features of microbiotas associated with models of metabolic syndrome. Specifically, we've observed that microbiotas associated with metabolic syndrome, in mice, express high levels of activators of the innate immune system and, moreover, penetrate the inner mucus layer thus encroaching upon intestinal epithelial cells. Our long-term goal is to define the molecular events that result in such alterations and develop approaches to restore a more beneficial host-microbiota relationship thus allowing design of modalities to ameliorate the metabolic syndrome epidemic in humans. Herein, we propose to advance toward this goal.

Public Health Relevance

Humanity is facing an epidemic of inter-related metabolic diseases collectively referred to as metabolic syndrome, the hallmarks of which include obesity, insulin resistance, hyperglycemia, hyperlipidemia, and hepatic steatosis. Metabolic syndrome greatly increases risk of developing diabetes, cardiovascular disease, and liver dysfunction. The incidence of metabolic syndrome and its highly morbid, chronic, and very costly downstream diseases threaten to overwhelm the world's healthcare systems and economies thus making it an enormous public health problem in dire need of reckoning. This proposal seeks to investigate mechanisms by which alterations in the gut microbiota might promote metabolic syndrome. Work will be performed in humans and tractable mouse models. We envisage that our work will increase understanding of mechanisms that might underlie the epidemic increase in metabolic disease in humanity and/or advance the possibility of manipulating the gut microbiota to treat and/or prevent metabolic disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK099071-05
Application #
9323386
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Perrin, Peter J
Project Start
2013-08-01
Project End
2020-06-30
Budget Start
2017-07-01
Budget End
2018-06-30
Support Year
5
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Georgia State University
Department
Miscellaneous
Type
Organized Research Units
DUNS #
837322494
City
Atlanta
State
GA
Country
United States
Zip Code
30302
Etienne-Mesmin, Lucie; Chassaing, Benoit; Adekunle, Oluwaseyi et al. (2018) Toxin-positive Clostridium difficile latently infect mouse colonies and protect against highly pathogenic C. difficile. Gut 67:860-871
Zou, Jun; Chassaing, Benoit; Singh, Vishal et al. (2018) Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health. Cell Host Microbe 23:41-53.e4
Chassaing, Benoit; Van de Wiele, Tom; De Bodt, Jana et al. (2017) Dietary emulsifiers directly alter human microbiota composition and gene expression ex vivo potentiating intestinal inflammation. Gut 66:1414-1427
Etienne-Mesmin, Lucie; Chassaing, Benoit; Gewirtz, Andrew T (2017) Tryptophan: A gut microbiota-derived metabolites regulating inflammation. World J Gastrointest Pharmacol Ther 8:7-9
Viennois, Emilie; Merlin, Didier; Gewirtz, Andrew T et al. (2017) Dietary Emulsifier-Induced Low-Grade Inflammation Promotes Colon Carcinogenesis. Cancer Res 77:27-40
Etienne-Mesmin, Lucie; Chassaing, Benoit; Adekunle, Oluwaseyi et al. (2017) Genome Sequence of a Toxin-PositiveClostridium difficileStrain Isolated from Murine Feces. Genome Announc 5:
Chassaing, Benoit; Vijay-Kumar, Matam; Gewirtz, Andrew T (2017) How diet can impact gut microbiota to promote or endanger health. Curr Opin Gastroenterol 33:417-421
Zhang, Benyue; Oyewole-Said, Damilola; Zou, Jun et al. (2017) TLR5 signaling in murine bone marrow induces hematopoietic progenitor cell proliferation and aids survival from radiation. Blood Adv 1:1796-1806
Chassaing, Benoit; Raja, Shreya M; Lewis, James D et al. (2017) Colonic Microbiota Encroachment Correlates With Dysglycemia in Humans. Cell Mol Gastroenterol Hepatol 4:205-221
Miles, Jennifer P; Zou, Jun; Kumar, Matam-Vijay et al. (2017) Supplementation of Low- and High-fat Diets with Fermentable Fiber Exacerbates Severity of DSS-induced Acute Colitis. Inflamm Bowel Dis 23:1133-1143

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