Featured Research

from universities, journals, and other organizations

'Body clock' dysregulation underlies obesity, more

Date:
May 14, 2014
Source:
Texas A&M AgriLife Communications
Summary:
A team of scientists has investigated how 'body clock dysregulation' might affect obesity-related metabolic disorders. "Animal sleeping and eating patterns, including those of humans, are subject to a circadian rhythmicity," one researcher said. "And previous studies have shown an association between the dysregulation of circadian or body clock rhythms and some metabolic disorders," adding that this study affirms that eating unhealthy foods causes health problems and that it's much worse to eat unhealthy foods at the wrong time.

A team of Texas A&M University System scientists have investigated how "body clock dysregulation" might affect obesity-related metabolic disorders.

The team was led by Dr. Chaodong Wu, associate professor in the department of nutrition and food sciences of Texas A&M's College of Agriculture and Life Sciences, and Dr. David Earnest, professor in the department of neuroscience and experimental therapeutics, Texas A&M Health Science Center.

Study results were published recently on the Journal of Biological Chemistry website.

"Animal sleeping and eating patterns, including those of humans, are subject to a circadian rhythmicity," Earnest said. "And previous studies have shown an association between the dysregulation of circadian or body clock rhythms and some metabolic disorders."

Wu said circadian clocks in peripheral tissues and cells drive daily rhythms and coordinate many physiological processes, including inflammation and metabolism.

"And recent scientific observations suggest that disruption of circadian clock regulation plays a key role in the development of metabolic diseases, including obesity and diabetes," he noted.

He said this study affirms that eating unhealthy foods causes health problems and that it's much worse to eat unhealthy foods at the wrong time. It also indicates that "time-based treatment may provide better management of metabolic diseases.

"To promote human health, we need not only to eat healthy foods, but also more importantly to keep a healthy lifestyle, which includes avoiding sleeping late and eating at night," he said.

Wu and Earnest said while previous studies using mice with genetic mutation of the removal of core clock genes has indicated that specific disruption of circadian clock function alters metabolism or produces obesity, the mechanism remained unknown. As key components of inflammation in obesity, macrophages, which are immune cells, contain cell-autonomous circadian clocks that have been shown to gate inflammatory responses.

"Our hypothesis was that overnutrition causes circadian clock dysregulation, which induces pro-inflammatory activity in adipose tissue. This then worsens inflammation and fat deposition, leading to systematic insulin resistance," Wu said.

To test the hypothesis, the team conducted experiments with "reporter mice" in which the circadian rhythmicity of various types of cells could be monitored by looking at their reporter activity. Accordingly, the reporter mice were put on a 12-hour light-dark cycle and were fed a high-fat diet. Additional reporter mice were fed a low-fat diet and served as controls. In this set of experiments, the team was able to characterize the effects of a high-fat diet on circadian clock rhythmicity and inflammatory responses in immune cells, or macrophages.

To further define a unique role for circadian clock dysregulation in metabolic disorders, the team conducted "bone marrow transplantation" experiments, through which the rhythmicity of circadian clocks was disrupted only in a specific type of immune cells. After high-fat diet feeding, the transplanted mice were used for collection of blood and tissue samples. A number of physiological and immunological assays also were performed on the mice.

Earnest said results showed that during obesity, that is when mice were fed a high-fat diet, the rhythmicity of circadian clocks in immune cells of fat tissue is dysregulated by a prolonged rhythmic period. This is, in turn, is linked to increased accumulation of immune cells in fat tissue and decreased whole-body insulin sensitivity.

"Animals on a high-fat diet display metabolic problems associated with obesity," Earnest said. "The problems are worsened in animals whose circadian clocks in immune cells are disrupted."

Earnest and Wu said the study will help those involved in human health and nutrition better understand the underlying mechanisms related to obesity and diabetes.


Story Source:

The above story is based on materials provided by Texas A&M AgriLife Communications. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. Xu, H. Li, S.-L. Woo, S.-M. Kim, V. R. Shende, N. Neuendorff, X. Guo, T. Guo, T. Qi, Y. Pei, Y. Zhao, X. Hu, J. Zhao, L. Chen, L. Chen, J.-Y. Ji, R. C. Alaniz, D. J. Earnest, C. Wu. Myeloid cell-specific Disruption of Period1 and Period2 Exacerbates Diet-induced Inflammation and Insulin Resistance. Journal of Biological Chemistry, 2014; DOI: 10.1074/jbc.M113.539601

Cite This Page:

Texas A&M AgriLife Communications. "'Body clock' dysregulation underlies obesity, more." ScienceDaily. ScienceDaily, 14 May 2014. <www.sciencedaily.com/releases/2014/05/140514182814.htm>.
Texas A&M AgriLife Communications. (2014, May 14). 'Body clock' dysregulation underlies obesity, more. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2014/05/140514182814.htm
Texas A&M AgriLife Communications. "'Body clock' dysregulation underlies obesity, more." ScienceDaily. www.sciencedaily.com/releases/2014/05/140514182814.htm (accessed August 29, 2014).

Share This




More Health & Medicine News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. Video provided by Newsy
Powered by NewsLook.com
How A 'Rule Of Thumb' Could Slow Down Drinking

How A 'Rule Of Thumb' Could Slow Down Drinking

Newsy (Aug. 28, 2014) A study suggests people who follow a "rule of thumb" when pouring wine dispense less than those who don't have a particular amount in mind. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins