Switch in Cell's 'Power Plant' Declines With Age, Says Research

A protein normally involved in blood pressure regulation in a surprising place: tucked within the little "power plants" of cells, the mitochondria, researchers at the Johns Hopkins University School of Medicine have found.
 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.