Many recent studies have suggested that obesity is associated with chronic inflammation in fat tissues. Researchers at Sanford-Burnham Medical Research Institute (Sanford-Burnham) have discovered that an imbalance between an enzyme called neutrophil elastase and its inhibitor causes inflammation, obesity, insulin resistance, and fatty liver disease.
This enzyme is produced by white blood cells called neutrophils, which play an important role in the body's immune defense against bacteria. The researchers found that obese humans and mice have increased neutrophil elastase activity and decreased levels of á1-antitrypsin, a protein that inhibits the elastase. When the team reversed this imbalance in a mouse model and fed them a high-fat diet, the mice were resistant to body weight gain, insulin resistance (a precursor to type 2 diabetes), and fatty liver disease. Their study appears April 2 in Cell Metabolism.
"The imbalance between neutrophil elastase and its inhibitor, á1-antitrypsin, is likely an important contributing factor in the development of obesity, inflammation, and other health problems. Shifting this balance—by either reducing one or increasing the other—could provide a new therapeutic approach to preventing and treating obesity and several obesity-related conditions," said Zhen Jiang, Ph.D., assistant professor in Sanford-Burnham's Diabetes and Obesity Research Center at Lake Nona, Orlando and senior author of the study.
What happens when you reduce neutrophil elastase levels
This study began when Jiang and his team noticed that neutrophil elastase levels are particularly high and á1-antitrypsin levels are low in a mouse model of obesity. Then they saw the same thing in blood samples from human male volunteers.
To further probe this curious neutrophil elastase-obesity relationship, the researcher turned once again to mouse models. They found that mice completely lacking the neutrophil elastase enzyme don't get as fat as normal mice, even when fed a high-fat diet. Those mice were also protected against inflammation, insulin resistance, and fatty liver. The same was true in a mouse model genetically modified to produce human á1-antitrypsin, which inhibits neutrophil elastase.
Normal mice on a high-fat diet were also protected against inflammation, insulin resistance, and fatty liver when they were given a chemical compound that inhibits neutrophil elastase. This finding helps validate the team's conclusions about neutrophil elastase's role in inflammation and metabolism and also suggests that a medicinal drug could someday be developed to target this enzyme.
Mechanism: how neutrophil elastase influences inflammation and metabolism
How do high neutrophil elastase levels increase inflammation and cause weight gain and other metabolic problems?
Jiang and his team began connecting the mechanistic dots. They discovered that neutrophil elastase-deficient mice have increased levels of several factors, including adiponectin, AMPK, and fatty acid oxidation. These are known for their roles in increasing energy expenditure, thus helping the body burn excess fat.
This research was funded by a Sanford-Burnham start-up fund, the American Diabetes Association (grant 7-11-BS-72), U.S. National Institutes of Health (National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK094025), and U.K. Medical Research Council (grant U117512772).
The study was co-authored by Virginie Mansuy-Aubert, Sanford-Burnham; Qiong L. Zhou, Sanford-Burnham; Xiangyang Xie, Sanford-Burnham; Zhenwei Gong, Sanford-Burnham; Jun-Yuan Huang, Sanford-Burnham; Abdul R. Khan, Sanford-Burnham, National Institute for Biotechnology and Genetic Engineering, Pakistan; Gregory Aubert, Sanford-Burnham; Karla Candelaria, Sanford-Burnham; Shantele Thomas, Sanford-Burnham; Dong-Ju Shin, Sanford-Burnham; Sarah Booth, U.K. National Institute of Medical Research; Shahid M. Baig, National Institute for Biotechnology and Genetic Engineering, Pakistan; Ahmed Bilal, Allied Hospital, Punjab Medical College; Daehee Hwang, Institute for Systems Biology; Hui Zhang, Institute for Systems Biology, Johns Hopkins University; Robin Lovell-Badge, U.K. National Institute of Medical Research; Steven R. Smith, Sanford-Burnham, Translational Research Institute, Florida Hospital; Fazli R. Awan, National Institute for Biotechnology and Genetic Engineering, Pakistan; Zhen Y. Jiang, Sanford-Burnham
About Sanford-Burnham Medical Research Institute
Sanford-Burnham Medical Research Institute is dedicated to discovering the fundamental molecular causes of disease and devising the innovative therapies of tomorrow. Sanford-Burnham takes a collaborative approach to medical research with major programs in cancer, neurodegeneration, diabetes, and infectious, inflammatory, and childhood diseases. The Institute is recognized for its National Cancer Institute-designated Cancer Center and expertise in drug discovery technologies. Sanford-Burnham is a nonprofit, independent institute that employs 1,200 scientists and staff in San Diego (La Jolla), California and Orlando (Lake Nona), Florida. For more information, visit us at sanfordburnham.org.
Heather Buschman | EurekAlert!
Further reports about: > Biotechnology > Cancer > Diabetes > Genetic clues > Lake Baikal > Pakistan > Translational Research > blood cell > blood sample > childhood disease > fatty liver > health problem > high-fat diet > insulin resistance > liver disease > mouse model > synthetic biology > weight gain > white blood cell
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy