The metabolic syndrome is a cluster of disorders that includes obesity, dyslipidemia, hypertension, non- alcoholic fatty liver disease and insulin resistance, all of which predispose to the development of diabetes and cardiovascular disease. Epidemiological and clinical data indicate that increased sugar, and particularly fructose, ingestion is a major contributor to the development of the metabolic syndrome and progression to diabetes. The mechanisms by which fructose consumption causes metabolic dysfunction remain elusive. Carbohydrate Responsive-Element Binding Protein (ChREBP) is a master transcriptional regulator of glycolytic and lipogenic gene programs which is activated by products of carbohydrate metabolism. SNPs in the ChREBP locus identified in genome-wide association studies predict features of the metabolic syndrome in human populations. We recently discovered a novel, potent constitutively active isoform of ChREBP, ChREBP-beta. In vivo, ChREBP-beta expression is acutely and robustly increased by fructose ingestion, but only modestly by glucose ingestion. Mice with whole-body genetic deletion of ChREBP die within several days of high-fructose feeding. In this proposal, we will pursue an integrative physiological approach to determine the role of ChREBP in fructose-induced metabolic disturbances. We hypothesize that ChREBP, and particularly ChREBP-beta, is a key regulatory element that is required for the normal adaptive metabolic response to fructose ingestion and also contributes to the development of metabolic disease and diabetes when sugar is consumed in excess. Using a combination of genetic and dietary interventions in mouse models, we will evaluate the role of ChREBP in integrated fuel homeostasis by pursuing the following three aims.
In Aim 1, using tissue-specific, loss-of-function mouse models, we will explore the physiologic and cellular mechanisms by which the absence of ChREBP impairs integrated fuel homeostasis and causes fructose intolerance.
In Aim 2, using a ChREBP gain-of-function mouse model combined with diets of different carbohydrate content and composition, we will explore a novel concept that the effects of ChREBP activity on integrated fuel homeostasis and insulin sensitivity depend on the nutritional context.
In Aim 3, we will develop a novel, ChREBP-beta isoform specific conditional loss-of-function mouse model to begin to determine the physiological significance of the distinct ChREBP isoforms in relation to integrated fuel metabolism and fructose induced metabolic disease. We anticipate that these studies will provide fundamental insight into mechanisms of fructose-induced metabolic disease and lay the groundwork for novel strategies for the prevention and treatment of obesity and diabetes.

Public Health Relevance

Increased sugar consumption is a major contributor to the obesity and diabetes epidemics, and the fructose component of table sugar appears to be particularly harmful. We have identified a key cellular factor called ChREBP that appears to play an important role in the biological response to fructose consumption. Using animal models, we will explore the function of this factor in fructose metabolism which will provide the crucial insiht needed to develop rational strategies to prevent and treat diabetes and obesity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK100425-01
Application #
8611060
Study Section
Special Emphasis Panel (ZRG1-EMNR-E (02))
Program Officer
Laughlin, Maren R
Project Start
2014-01-15
Project End
2018-12-31
Budget Start
2014-01-15
Budget End
2014-12-31
Support Year
1
Fiscal Year
2014
Total Cost
$378,450
Indirect Cost
$160,950
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
071723621
City
Boston
State
MA
Country
United States
Zip Code
02215
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Kim, Mi-Sung; Krawczyk, Sarah A; Doridot, Ludivine et al. (2016) ChREBP regulates fructose-induced glucose production independently of insulin signaling. J Clin Invest 126:4372-4386
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