Research Project: Modification of Diurnal Patterns to Promote Health in Models for Human Metabolic Dysfunction

Location: Dietary Prevention of Obesity-related Disease Research

2022 Annual Report

Objectives
Objective 1 - Define how dietary fatty acids and exercise alter peripheral biological rhythms and metabolic dysfunction. • Subobjective 1.A. Define whether long-chain n3 polyunsaturated fatty acids correct the obesity-mediated peripheral circadian clock dysfunction. • Subobjective 1.B. Define the extent to which exercise overrides peripheral clock dysfunction and metabolic dysfunction. Objective 2 - Define the impact of diet timing on colonic bile acid pathways and inflammation. Objective 3 - Define the impact of dietary fiber composition on colonic bile acid pathways and inflammation. Objective 4 - Define the mechanisms and the influence of daily physical activity timing to improve bone health. • Subobjective 4.A. Determine the mechanisms through which the timing of exercise alters the diurnal pattern of bone turnover, bone cell physiology, calcium utilization, and bone structure. • Subobjective 4.B. Determine the efficacy of morning vs evening exercise to maximize bone anabolic effects.

Approach
Disruption of biological rhythms in peripheral organs by environmental cues leads to metabolic dysfunction and disorders, including obesity. Food and physical exercise can drive the biological rhythms in peripheral organs. This project will examine the ability of dietary components (dietary fatty acids and fiber), exercise, and the timing of food consumption and exercise to correct the disrupted biological rhythms in peripheral organs and restore metabolic homeostasis. This project will address three questions: (1) Do changes in dietary fatty acid composition and exercise override the disrupted peripheral biological rhythms and restore metabolic homeostasis? (2) Does the timing of food intake and dietary fiber composition regulate bile acid pathways and attenuate colonic inflammation? (3) Does the timing of physical exercise make differences in regulating the diurnal pattern of bone metabolism and improving bone formation? Rodent studies will be performed to address each of these questions. In addition, a human clinical trial will be performed to translate question 3 results to humans. This project takes innovative approaches to addressing these questions in the context of modifying the diurnal patterns to promote health. Results from this research will provide valuable information of how dietary fatty acids and exercise minimize metabolic dysfunction and prevent associated disorders, a greater understanding of food timing and dietary fiber in regulating bile acid pathways and informing guidance for reducing colonic inflammation, and a greater understanding of timing of exercise training in improving bone health, particularly to people with bone loss associated with advancing age.

Progress Report
Objective 1. Research continued on investigating the effects of the daily timing of eating and dietary fatty acids on metabolic health in rodent models of human adult obesity. Obesity disturbs the daily rhythm of the biological clock that controls metabolic homeostasis. Eating irregularity contributes to obesity. Time-restricted feeding to the active phase of the day may restore biological rhythms in rodent models of obesity. Fish oil (a rich source of long-chain n3-polyunsaturated fatty acids) improves insulin sensitivity and reduces the risk of obesity in laboratory rodents. ARS scientists are currently investigating the benefits of time-restricted feeding and dietary supplementation with long-chain n3-polyunsaturated fatty acid in restoring the daily biological rhythms and reducing the risk of adult obesity. As a subordinate project of Objective 1, ARS scientists have extended their research to investigate the effects of biological rhythm disturbance on pubertal metabolic health. Childhood obesity is associated with adulthood obesity and is a risk factor for breast cancer in women. In these investigations, ARS scientists focused on the impact of alterations in the biological clock on (1) metabolic homeostasis and (2) early stage of breast cancer in pubertal models of obesity. Objective 2. Research continued on investigating whether time-restricted feeding (TRF, without reducing energy intake) reduces colonic inflammation in a mouse model of obesity. It has been shown that TRF improves colon health. However, the molecular impact of TRF on colonic inflammation remains to be determined. Body weight, body composition, blood, liver, fecal samples, and the colon have been collected to assess the effects of TRF on colonic inflammation via multiple-omics approaches (e.g., microbiome, metabolome). Objective 3. ARS scientists completed a study investigating the mechanisms and the impact of resistant starch against colonic inflammation in a mouse model fed an obesity-causing diet. The consumption of a high-fat, low-fiber Western-style diet contributes to obesity, a risk factor for colonic inflammation and ensuing colon cancer. Conversely, diets rich in fiber (e.g., resistant starch) reduce the risk of intestinal disorders and cancer. In this study, ARS scientists used biochemical, histological, and multi-omics approaches including microbiome and metabolome to determine whether an increase in dietary resistant starch reduces inflammation and early cancer markers in the colon in a mouse model of obesity. As subordinate projects of Objective 3, (1) ARS scientists have been analyzing the fecal oncogenic signatures in the inflammatory colon of a mouse study which was designed to determine the underlying mechanistic basis of obesogenic diets and colonic inflammation. (2) ARS scientists have been analyzing the metabolome of colonic contents collected from a mouse study which was designed to determine the underlying metabolic basis of obesity-related colon cancer. Objective 4. Research continued on investigating the mechanisms and the influence of the time of day of exercise on bone metabolism in ovariectomized rats – a model of human menopause. ARS scientists completed sample analyses collected from an animal study investigating the impact of the daily timing of exercise on bone. Female ovariectomized or sham-operated Sprague Dawley rats exercised at either rest phase, early active phase, or late active phase five days per week for 12 weeks. Body composition, body weight, serum bone biomarkers, bone structure, and gene expressions were measured to determine the effects of exercise at different times on these parameters. In addition, ARS scientists have written and submitted a protocol for Subobjective 4B determining the effects of the time of day exercise on bone related changes in postmenopausal women. The protocol has been submitted for Institutional Review Board review. As a subordinate project of Objective 4, ARS scientists were collaborating with a scientist at Mount Sinai School of Medicine and finished analyses of bone samples collected from a study investigating the role of follicle-stimulating hormone in regulating bone mass and body composition in mice. Studies show that follicle-stimulating hormone regulates the development, growth, and reproductive processes of the body and is a potential therapeutic target for preventing osteoporosis and obesity.

Accomplishments
1. Fat tissue-derived bioactive chemicals contribute to male breast cancer development and growth. Male breast cancer is a rare but highly invasive cancer with poor prognosis. Obesity is a risk factor for breast cancer. Body fat produces biological active chemicals (for example, monocyte chemotactic protein-1, MCP-1) that may contribute to breast cancer growth. ARS scientists found that depletion of MCP-1 from body fat tissues results in a slower mammary tumor growth rate and smaller mammary tumors in male obese mice. This research provides insight into the role of fat-derived bioactive chemicals in male breast cancer development and growth. It is of interest to scientists in government, academia, and industry. Findings from this work demonstrate the importance of obesity prevention in promoting human health and wellbeing.

2. Metabolism of lung cancer differs from that of the healthy lungs. Lung cancer is the leading cause of cancer-related deaths to both men and women in the United States. Cancerous metabolism may be associated with the aggressiveness of disease progression. ARS scientists found that amino acid and energy metabolism in lung cancer tissues differ from that in the healthy lung tissues and that obesity exacerbates the lung cancer-mediated metabolic abnormality. Findings from this research provide insights into lung cancer metabolism which can be useful in designing further studies aimed at diet and lung cancer prevention.

3. Depletion of monocyte chemotactic protein-1 from the body mitigates the growth and metabolism of lung cancer. Cancer cells consumes more energy and nutrients than normal healthy organs for its rapid growth. Monocyte chemotactic protein-1 (MCP-1) is a bioactive chemical mainly derived from body fat mass and other organs. Its elevation in the body may facilitate cancer growth. ARS scientists found that depletion of MCP-1 from the entire body mitigates lung tumor growth and alters energy metabolism in a mouse model of lung cancer. This research provides insight into MCP-1 in lung cancer metabolism and growth. It is of interest to scientists in government, academia, and industry working on lung cancer prevention and treatment.

4. Consumption of an obesogenic high fat diet increases leaky gut risk. Diet-related obesity is associated with an increased risk of intestinal inflammation. While it is known that obesogenic diets such as high fat diets increase bile acids and ensuing inflammation in the colon, the underlying mechanisms remain to be elucidated. ARS scientists in Grand Forks, North Dakota, demonstrated that colonic bile acids reduce cell-cell connection in the gut. These findings provide cellular insights into the detrimental effect of high-fat consumption on gut health. These findings will build the foundation for clinical trials to evaluate the role of diet in gut health and colon health promotion in humans. The research will have impact for scientists in government, academia, and industry studying the roles of diet in colon health.

5. Identification of plasma signatures for diet-induced obesity and colon cancer. Consumption of a high-fat diet links obesity to colon cancer in humans. However, the underlying metabolic basis remains to be determined. ARS scientists in Grand Forks, North Dakota, along with collaborators, demonstrated that chemical-induced colon cancer changes cholesterol metabolism in a mouse model of obesity. This research provides mechanistic and nutritional insights into the diet-related obesity and colon cancer. This work is of interest to health professionals, basic and clinical scientists, and the general public.

6. The time of day for exercise does not affect the beneficial effect of exercise on bone structure in older female rats. Changes of bone resorption and formation markers exhibit daily patterns, and disruption of the daily pattern affects the balance of bone turnover leading to bone deterioration. ARS scientists in Grand Forks, North Dakota, investigated whether the time of day for exercise alters bone metabolism in a rodent model. The study demonstrated that exercise increased femoral bone mass and there were no differences in bone structural parameters among rats exercised at different times. The findings are of interest to researchers in basic and clinical areas, as well as the general public as the study suggests that exercise benefits bone regardless of the time of day to exercise.

7. Blocking follicle stimulating hormone action with a novel antibody prevents obesity and increases bone mass in mice. The risk of developing osteoporosis and obesity is increased right before and during menopause. Follicle stimulating hormone (FSH), a hormone produced by pituitary gland in the brain, may play an important role in regulating these two health disorders. ARS scientists in Grand Forks, North Dakota, along with collaborators, demonstrated that blocking FSH action with a specific antibody decreased total mass and fat mass, and increased femoral bone mass and the expression of bone formation genes. The findings are of interest to basic scientists as the study suggests that targeting FSH action can be a potential therapeutic strategy for improving bone health and reducing obesity.

Review Publications
Yan, L., Sundaram, S., Rust, B.M., Picklo, M.J., Bukowski, M.R. 2021. Mammary tumorigenesis and metabolome in adipose specific monocyte chemotactic protein-1 deficient male MMTV-PyMT mice fed a high-fat diet. Frontiers in Oncology. 11. Article 667843. https://doi.org/10.3389/fonc.2021.667843.
Zeng, H., Umar, S., Liu, Z., Bukowski, M.R. 2021. Azoxymethane alters the plasma metabolome to a greater extent in mice fed a high fat diet compared to an AIN-93 diet. International Journal of Molecular Sciences. https://doi.org/10.3390/metabo11070448.
Yan, L., Sundaram, S., Rust, B., Picklo, M.J., Bukowski, M.R. 2022. Metabolomes of Lewis lung carcinoma metastases and normal lung tissue from mice fed different diets. Journal of Nutritional Biochemistry. 107. Article 109051. https://doi.org/10.1016/j.jnutbio.2022.109051.
Zeng, H., Safratowich, B.D., Cheng, W., Larson, K.J., Briske Anderson, M.J. 2022. Deoxycholic acid modulates cell-junction gene expression and increases intestinal barrier dysfunction in Caco-2 cell monolayers. Molecular Nutrition and Food Research. https://doi.org/10.3390/molecules27030723.
Chung, E., Elmassry, M., Cao, J.J., Kaur, G., Dufour, J., Hamood, A., Chwan-Li, S. 2021. Beneficial effect of dietary geranylgeraniol on glucose homeostasis and bone microstructure in obese mice is associated with suppression of proinflammation and modification of gut microbiome. Journal of Agricultural and Food Chemistry. 93:27-37. https://doi.org/10.1016/j.nutres.2021.07.001.
Cao, J.J., Jahns, L., Roemmich, J.N. 2021. Providing vegetables at the amount recommended by the Dietary Guidelines for Americans decreases urinary acidity and bone turnover: an 8-wk randomized controlled trial. Journal of Nutrition. 151:3413-3420. https://doi.org/10.1093/jn/nxab255.
Yan, L., Rust, B.M., Sundaram, S., Picklo, M.J., Bukowski, M.R. 2022. Alteration in plasma metabolome in high-fat diet-fed monocyte chemotactic protein-1 knockout mice bearing pulmonary metastasis of Lewis lung carcinoma. Nutrition and Metabolic Insights. 107. Article 109051. https://doi.org/10.1016/j.jnutbio.2022.109051.
Cao, J.J. 2022. Calcium consumption is beneficial to bone health in obese, postmenopausal women. Journal of Nutrition. 152:922-923. https://doi.org/10.1093/jn/nxac008.