Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC
PZ HTL SA

Insulin Resistance Also Mediated by White Blood Cells

By BiotechDaily International staff writers
Posted on 13 Aug 2012
Image: False-color scanning electron micrograph (SEM) of a neutrophil (Photo courtesy of UC San Diego School of Medicine).
Image: False-color scanning electron micrograph (SEM) of a neutrophil (Photo courtesy of UC San Diego School of Medicine).
Researchers have now found that neutrophils play a role in mediating the development of insulin resistance, the central characteristic of type 2 diabetes. The discovery also provides a potential new treatment target.

Using live mouse models as well as cultured liver and fat cells, a study team based at the University of California, San Diego, School of Medicine (La Jolla, CA, USA) discovered that an enzyme secreted by neutrophils called neutrophil elastase (NE) impairs insulin signaling and boosts resistance. Conversely, deletion of NE in obese mice fed a high-fat diet improved insulin sensitivity. “These results are largely unexpected. Although several immune cells have been established in the etiology of insulin resistance, the role of neutrophils in this process has remained unclear until now,” said Da Young Oh, co-author and assistant project scientist in the laboratory of study leader Jerrold M. Olefsky, MD and professor of medicine.

Chronic low-grade inflammation is an important cause of systemic insulin resistance. Neutrophils are the first immune cells to respond to tissue inflammation and can promote chronic inflammation by helping to recruit additional white blood cells - macrophages. Oh noted that neutrophils were considered to be “transient infiltrates” incapable of sustaining chronic, low-grade inflammation. “Our studies now suggest neutrophils possess powerful immune modulatory effects,” Oh said. Specifically, neutrophils use NE to activate a signaling pathway that triggers macrophages to secrete proinflammatory cytokines. NE degrades IRS1, a key protein in the insulin-signaling pathway in both liver and fat cells. The scientists noted that although NE has been shown to degrade this protein in lung cancer cells, the effect on insulin target tissues such as liver and adipose is striking.

The insulin-mediating role of neutrophils makes them a new target for developing treatments of insulin resistance in particular and diabetes in general. “One could, in theory, take an NE activity inhibitory approach to reverse or improve insulin resistance,” Oh said, noting that NE inhibiting drugs are already used for treatment of emphysema in Japan and are being tested in the United States for both emphysema and type 1 diabetes.

The findings have been reported in the August 5, 2012, advance online edition of the journal Nature Medicine.

Related Links:

University of California, San Diego, School of Medicine



comments powered by Disqus

Channels

Genomics/Proteomics

view channel
Image: This novel, flexible film that can react to light is a promising step toward an artificial retina (Photo courtesy of the American Chemical Society).

Novel Nanofilm May Be Artificial Retina Precursor

Researchers have used advanced nanotechnology techniques to develop a light-sensitive film that has potential for future artificial retina applications. Investigators at the Hebrew University of Jerusalem... Read more

Biochemistry

view channel

Blocking Enzyme Switch Turns Off Tumor Growth in T-Cell Acute Lymphoblastic Leukemia

Researchers recently reported that blocking the action of an enzyme “switch” needed to activate tumor growth is emerging as a practical strategy for treating T-cell acute lymphoblastic leukemia. An estimated 25% of the 500 US adolescents and young adults diagnosed yearly with this aggressive disease fail to respond to... Read more

Business

view channel

R&D Partnership Initiated to Reduce Development Time for New Drugs

nanoPET Pharma, GmbH (Berlin, Germany) signed an open-ended framework contract with the international pharmaceutical company Boehringer Ingelheim (Ridgefield, CT, USA). By developing customized contrast agents for research in both basic and preclinical studies, nanoPET Pharma will contribute to the enhancement of Boehringer... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.