Scientists are learning that the dynamic regulation of genes  as much as the genes themselves  shapes the fate of organisms. Now the discovery of a new epigenetic mechanism regulating genes in the brain under stress is helping change the way scientists think about psychiatric disorders and could open new avenues to treatment.
In trying to explain psychiatric disorders, genes simply cannot tell the whole story. The real answers are in the interaction of genes and the environment. Post-traumatic stress disorder requires some trauma, for instance, and people, for the most part, aren’t born depressed. Now research has revealed one mechanism by which a stressful experience changes the way that genes are expressed in the rat brain. The discovery of “epigenetic” regulation of genes in the brain is helping change the way scientists think about psychiatric disorders and could open new avenues to treatment.
Richard Hunter, a postdoc in Rockefeller University’s Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, found that a single 30-minute episode of acute stress causes a rapid chemical change in DNA packaging proteins called histones in the rat hippocampus, which is a brain region known to be especially susceptible to the effects of stress in both rodents and humans. The chemical change Hunter examined, called methylation, can either increase or decrease the expression of genes that are packaged by the histones, depending on the location of the methylation.
Richard G. Hunter, Ph.D. is Research Associate, Laboratory of Neurobiology and Behavior, Laboratory of Neuroendocrinology, Rockefeller University.
Richard’s doctoral studies were focused on understanding how the neuropeptide Cocaine-Amphetamine-Regulated Transcript (CART), interacted with the dopamine system in the basal ganglia, and he discovered that it was regulated primarily via D3 receptors in the nucleus accumbens. In addition, he helped to demonstrate that CART is both regulated by and exerts a regulatory influence on the hypothalamic-pituitary-adrenal (HPA) stress axis, a series of findings that awakened his curiosity about stress and neuroendocrinology.
His work at the Neuro-epigenetics working group at the Rockefeller University which he helped establish has led to further studies, now in progress, exploring the extent to which the large scale modification of hippocampal histones represents a “genomic stress response” perhaps specific to terminally differentiated neurons. He is deeply curious about the potential epigenetics has for producing new ways of looking at the biology of mental disease and aging and looks forward to the potential for new ideas and approaches to utilize the tools he has acquired in novel systems.
He coauthored Intra-Ventral Tegmental Area Injection of Rat Cocaine and Amphetamine-Regulated Transcript Peptide 55–102 Induces Locomotor Activity and Promotes Conditioned Place Preference, Species differences in brain distribution of CART mRNA and CART peptide between prairie and meadow voles, Regulation of Kainate Receptor Subunit mRNA by Stress and Corticosteroids in the Rat Hippocampus, Regulation of CART mRNA by Stress and Corticosteroids in the Hippocampus and Amygdala, CART in feeding and obesity, Studies of selected phenyltropanes at monoamine transporters, and CART Peptides: Modulators of Mesolimbic Dopamine, Feeding, and Stress.
Richard earned his Bachelor’s degree in Biology at the University of Texas at Austin in 1995 and his Ph.D. in Molecular and Systems Pharmacology at Emory University in 1994.
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