A researcher at the Health Science Center has won a $200,000 grant to study brain molecular changes that reduce our ability to learn and remember as we age.
Ravi Ranjan, Ph.D., is one of only three Texas scientists to receive the New Scholar Award in Aging this year from the Ellison Medical Foundation. The award is for four years and is designed to provide significant support to young investigators selected for their potential to become leaders in the field of aging.
Dr. Ranjan, who studies aging in a fruit fly species called Drosophila melanogaster, is with the Health Science Center’s Sam and Ann Barshop Institute for Longevity and Aging Studies and is an assistant professor in the department of pharmacology at the Health Science Center. He was recruited from Harvard University in 2004.
Dr. Ranjan studies molecular mechanisms that change “synaptic plasticity” during aging. Synapses are points throughout the brain where nervous impulses are sent from one neuron to another. Like opposite rims of a canyon, a synapse consists of pre- and post-synaptic endings with a space between. Information is transmitted across these gulfs.
“As we grow, new synapses form in the brain, and the synaptic endings are very flexible,” Dr. Ranjan said. “This quality enables children to learn more readily. As we get older, learning at the same level and speed is not possible because the structure and function of our synapses change. They become more rigid as we age.”
Dr. Ranjan particularly focuses on the molecules glutamate and insulin. The release of these chemicals is important in learning and memory.
He is studying a fruit fly in which a gene called the “Methuselah gene” has been altered, resulting in greatly extended life span. In addition to long life, Dr. Ranjan has shown that Methuselah flies learn better during old age than unaltered flies do. This was demonstrated by pairing a tiny electric shock with a specific odor, and comparing how quickly the flies learned to avoid the odor.
Subsequently, Dr. Ranjan found that the synapses in the brains of Methuselah flies released smaller amounts of glutamate. He also showed that mutating the Methuselah gene only in insulin-secreting cells in the brain increased life span and may improve learning and memory.
“Fruit flies live 60 to 80 days, far from a human life span, but they yield valuable clues that one day might be useful in helping prevent the molecular changes that damage synapses and contribute to learning and memory problems of human aging,” Dr. Ranjan said. “The Ellison New Scholar Award is very important in helping me to continue and accelerate this research.”
Yidong Bai, Ph.D., assistant professor of cellular and structural biology at the Health Science Center, is a previous Ellison New Scholar Award winner. In addition, the Health Science Center has had several Ellison Senior Scholar in Aging Award winners, including Arlan Richardson, Ph.D.; Olivia Pereira-Smith, Ph.D.; Pamela Larson, Ph.D.; James Nelson, Ph.D.; Steven Austad, Ph.D.; Peter Hornsby, Ph.D.; and Jan Vijg, Ph.D.
The Ellison Medical Foundation supports basic biomedical research on aging relevant to understanding aging processes and age-related diseases and disabilities. The Foundation particularly wishes to stimulate new, creative research that might not be funded by traditional sources or that is often under-funded in the U.S.