Recipient Organization
OKLAHOMA STATE UNIVERSITY
(N/A)
STILLWATER,OK 74078
Performing Department
Human Sciences
Non Technical Summary
Chronic inflammation and the corresponding pro-oxidative state produced by activated immune cells damage many tissues that can lead to the development of numerous chronic conditions including insulin resistance (IR), obesity, and type 2 diabetes (T2D). Obesity and T2D are all major health issues in the US particularly in Oklahoma. More than one-third (36.5%) of US adults are obese and Oklahoma was the seventh worst state in the prevalence of obesity. The rise in obesity leads to the development of many chronic conditions including IR, heart disease and T2D. In 2015, 30.3 million Americans (9.4%) had diabetes and another 84.1 million had pre-diabetes. Based on these alarming statistics, it is apparent that obesity and T2D are having a significant impact on the quality of life of many Americans along with the economic burden it represent to our healthcare system. Therefore, it is imperative to understand factors that contribute to obesity and T2D and develop effective prevention and treatment strategies to reduce the impact of these conditions, particularly in Oklahoma. This study will investigate the role of the anti-inflammatory molecule interleukin (IL)-10 in the development of IR.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Recent findings demonstrate the importance of IL-10 in reducing inflammation in the gut and the skeletal muscle. However, to our knowledge there are limited studies that examined the effects of IL-10 on other tissues important in glucose homeostasis such as the liver and adipose tissue. In addition to IL-10, the western diet (WD, high fat and high sugar)) increases inflammation through its effects on the immune cells particularly T cells and the gut bacterial population. A distinct intestinal microbial population which subsequently alters short chain fatty acid (SCFAs) levels is linked to the development of obesity and T2D. The aims of this proposed study are:Aim 1: To investigate the effects of IL-10 on: a) glucose homeostasis and if the anti-inflammatory effects of IL-10 protect tissues important in glucose homeostasis (e.g. small intestine, liver, adipose tissue, and muscle); and b) the gut bacterial population and SCFAs production and if these changes alter T cell populations within the gut and leads to systemic and tissue inflammation.Aim 2: To identify intervention strategies (e.g. wheat germ (WG) supplementation) that can positively affect the gut microbiome, SCFAs production, and T cell populations which can subsequently attenuate obesity and markers of IR in the context of Western diet and absence of IL-10.These effects will be investigated in wild type and IL-10 knock-out (KO) mouse models under conditions consistent with the normal and Western diet. The approach of using natural products such as WG or their bioactive components to reduce or prevent chronic disorders particularly obesity, IR and T2D has been the long-term goal of our laboratory.
Project Methods
We have designed a series of animal experiments that will enable us to gain an understanding as to how IL-10 protects against obesity and IR. These experiments will also allow us to investigate how the changes in the gut microbiome and subsequent SCFAs production alter T cell populations (e.g. Th17 and T regulatory cells) and if their activation within the gut contributes to systemic and inflammation in tissues vital to glucose homeostasis. Additionally, whether these changes are attenuated by dietary manipulations and its relationship to IR will also be explored. In terms of the dietary factors that will be manipulated, we will investigate the extent to which the Western diet exacerbates or supplementation with WG improves the aforementioned parameters in the absence of IL-10. These experiments will require that we maintain a mouse colony of IL-10 KO mice. Initial breeding pairs of the IL-10 KO mice will be purchased from Jackson Laboratories (Bar Harbor, ME) as well as age- and gender-matched C57BL/6 mice for each experiment.Due to scope of the proposed work and the number of animals required, we have developed our experiments in three phases. In Phase I, we will investigate the effects of IL-10 on glucose homeostasis and the corresponding shifts in T cell population over time under normal dietary conditions. Male IL-10 KO and wild-type (WT) mice will be maintained on a control diet (AIN-93)46 with study end-points at 3 and 6 mos. The earliest time point that demonstrates significant alterations in glucose homeostasis and an inflammatory response will be designated as the single study end-point for all subsequent experiments. In Phase II, a similar experiment will be designed to determine whether the Western diet exacerbates the inflammatory response in IL-10 KO mice. The control or AIN-93 diet will be formulated to provide 10% kcal from fat compared to the Western diet which will provide 45% kcal from fat and be high in refined sugars.46-47 Finally, in Phase III, we will investigate how supplementing the diet with WG will affect the microbiome, increase luminal SCFA, alter T cell population and subsequent alterations in markers of IR.Throughout all experiments, mice will be housed in groups (n=3-4/cage), have free access to deionized water, and will be matched-fed to control for food intake in each mouse strain. Body weights will be recorded on a weekly basis. At the end of each experiment, mice will be anesthetized, undergo a whole body dual-energy x-ray absorptiometry (DXA) scan to assess body composition, and then bled from the carotid artery. An aliquot of whole blood will be used to determine a complete blood count (i.e., total white cell counts and differentials). Serum and tissues important in glucose homeostasis (e.g. muscle, liver, adipose tissue, and gut samples) will be collected. All procedures will strictly adhere to the guidelines set forth by the Oklahoma State University Animal Care and Use Committee. All the methodology proposed in our study will be conducted to accomplish each of the proposed aims listed below.Aim 1:A. To investigate the effects of IL-10 on glucose homeostasis and if the anti-inflammatory effects of IL-10 protect tissues important in glucose homeostasis (e.g. small intestine, liver, adipose tissue, and muscle).B. To investigate the effects of IL-10 on the gut microbiome and SCFAs production and if these changes alter T cell populations (e.g. Th17 and T regulatory cells) within the gut and leads to systemic and tissue inflammation.Aim 2. To identify intervention strategies (e.g. wheat germ supplementation) that can positively affect the gut microbiome, SCFAs production, T cell populations which can subsequently attenuate obesity and markers of IR in the context of Western diet and absence of IL-10.