The quantity of this protein appears to decrease with age, but treating older mice with the blood pressure medication losartan can increase protein numbers to youthful levels, decreasing both blood pressure and cellular energy usage.
The researchers say these findings, published online during the week of August 15, 2011, in the Proceedings of the National Academy of Sciences, may lead to new treatments for mitochondrial–specific, age-related diseases, such as diabetes, hearing loss, frailty and Parkinson's disease.
"We've identified a functional and independently operated system that appears to influence energy regulation within the mitochondria," explains Jeremy Walston, M.D., professor of geriatric medicine at Hopkins. "This mitochondrial angiotensin system is activated by commonly utilized blood pressure medications, and influences both nitric oxide and energy production when signaled."
Previous research showed that manipulating angiotensin in the body's cells had unexpectedly affected mitochondrial energy production, so Walston and Peter Abadir , M.D., an assistant professor of geriatric medicine, decided to examine the role of angiotensin within the mitochondria. Using high-powered microscopy, they and their collaborators found evidence within the mitochondria of angiotensin as well as one of the protein receptors that bind to and detect it. They also pinpointed the angiotensin receptor's exact locations within the mitochondria of mouse kidney, liver, neuron and heart cells as well as in human white blood cells.
The team then treated mitochondria with a chemical known to activate the angiotensin receptors and measured the cell's response. This resulted in a decrease in oxygen consumption by half and a small increase in nitric oxide production—indicating less energy made by the mitochondria and lowered blood pressure, respectively. Explains Walston, "Activating angiotensin receptors within the mitochondria with these agents led to lowered blood pressure and decreased cellular energy use."
But they found even more than just an energy-regulating mechanism; after testing the angiotensin system in mitochondria of both young and old mice, they noticed a decrease by almost a third of the amount of the angiotensin receptor type 2 in the mitochondria in older mice, meaning that cells in older mice were unable to control energy use as well. The researchers then tried treating these older mice with the blood pressure lowering drug losartan daily for 20 weeks and found that the number of these receptors increased. "Treatment of the old mice with losartan resulted in a marked increase in the number of receptors that are known to positively influence blood pressure and decrease inflammation," says Walston.
Declining mitochondria are known to influence chronic diseases in older adults, explains Walston, whose next step is to translate studies from cell culture and animal based studies to human studies in hopes of developing new therapies. "Our findings will help us determine if the drugs that interact with this receptor will also lead to improvement of mitochondrial function and energy production. This, in turn, could facilitate the treatment of a number of chronic diseases of older adults."
This study was funded by the Johns Hopkins Older Americans Independence Center, the National Institute on Aging and the American Geriatrics Society.
Additional authors on this study from the Division of Geriatric Medicine and Gerontology at Johns Hopkins were Peter Abadir, Alka Jain, and Neal Fedarko.
John Lazarou | 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