A team of Harvard School of Public Health (HSPH) scientists report finding a molecular "switch" that can "turn off" some cellular processes that are protective against aging and metabolic diseases.
While more research is needed, the findings may open doors for new drug treatments to halt or slow development of metabolic diseases like type 2 diabetes or heart disease. The research findings appear in the December 1, 2010 issue of Cell Metabolism.
Scientists want to better understand why some people – often those who are older, overweight, or obese – develop metabolic syndrome, a condition characterized by a group of risk factors, including high blood glucose, high cholesterol, insulin resistance, fatty liver, and increased abdominal fat. This condition increases the risk of heart disease, type 2 diabetes, and other diseases, including cancer.
Using genetically altered mouse models, senior author Chih-Hao Lee, assistant professor of genetics and complex diseases at HSPH, first author Shannon Reilly, an HSPH graduate student, and their colleagues focused on the role of the protein SMRT (silencing mediator of retinoid and thyroid hormone receptors) in the aging process. They found aged cells accumulate more SMRT and wanted to see if SMRT increases the damaging effects of oxidative stress on mitochondria, the cell component that converts food and oxygen into energy and powers metabolic activities. Oxidative stress is a cellular process that damages DNA, protein, and other cell functions and can lead to age-related diseases such as type 2 diabetes, Alzheimer's, Parkinson's, and atherosclerosis.
In laboratory experiments, Reilly, Lee, and colleagues found that in older animals SMRT acts like a "switch," turning off the protective cellular activities of proteins known as peroxisome proliferator-activated receptors (PPARs). PPARs help regulate genes that promote fat burning to maintain lipid (blood fat) balance and reduce oxidative stress. The researchers were able to reduce the negative effects of oxidative stress by giving antioxidants or drugs known to turn the protective activities of PPARs back on.
The scientists knew that oxidative damage causes the body to age. What they did not know is why aged cells have more oxidative damage. "The significance of our study is that we show SMRT facilitates this process," Lee said. "In other words, the normal metabolic homeostasis is maintained, in part, by PPARs. SMRT acts as a metabolic switch to turn off PPAR activities when the cells age."
PPAR drugs have been used to increase insulin sensitivity and lower blood lipid levels. "Our study shows PPARs might also be used to boost the body's ability to handle oxidative stress," Lee said.
"With what we have learned, we believe SMRT is one of the key players that causes age-dependent decline in mitochondrial function by blocking PPAR activity, and we've found a way to boost the body's ability to better handle metabolic and oxidative stress," Lee said. "This finding is significant since increased oxidative stress, coupled with reduced metabolic function, contributes to the aging process and the development of age-related metabolic diseases."
In collaboration with epidemiologists at HSPH, the team found genetic variations in the human SMRT gene that are associated with risk of type 2 diabetes. "Through this study we were able to validate that our findings in the animal model apply to human diseases," Lee said.
Support for the study was from the National Institutes of Health as well as from the American Diabetes Association and American Heart Association. Lee received a Career Incubator Fund from HSPH that also supported the work.
"Nuclear Receptor Corepressor SMRT Regulates Mitochondrial Oxidative Metabolism and Mediates Aging-Related Metabolic Deterioration," Shannon M. Reilly, Prerna Bhargava, Sihao Liu, Matthew R. Gangl, Cem Gorgun, Russell R. Nofsinger, Ronald M. Evans, Lu Qi, Frank Hu, Chih-Hao Lee. Cell Metabolism, December 2010.
Visit the HSPH website for the latest news, press releases and multimedia offerings.
Harvard School of Public Health (http://www.hsph.harvard.edu) is dedicated to advancing the public's health through learning, discovery, and communication. More than 400 faculty members are engaged in teaching and training the 1,000-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children's health to quality of care measurement; from health care management to international health and human rights. For more information on the school visit: http://www.hsph.harvard.eduHSPH on Twitter: http://twitter.com/HarvardHSPH
Marjorie Dwyer | EurekAlert!
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences