Epigenetic Regulation of Neurodegenerative Processes After Repetitive Traumatic Brain Injury

This research proposal addresses how metabolic alterations caused by two types of repetitive injury (blast and impact) lead to long-term epigenetic changes that result in neurodegeneration. This project aims to determine the consequences of TBI-mediated dysregulation of TCA metabolites (AKG and 2HG) in epigenetic regulation of neurodegeneration progression in a 3D in vitro brain tissue after single or repetitive mild blast/blunt injury. To address the goals of this project, we will use our unique
3D in vitro model of brain tissue that we developed to study the cellular and molecular mechanisms of blast and blunt impact injury. We will combine epigenetic and metabolic approaches to (1) determine whether the AKG: 2HG ratio correlates with mitochondrial dysfunction and neuronal network degeneration post single moderate
and repetitive mild blast or blunt injury; and (2) determine whether altering the AKG:2HG ratio therapeutically will improve neuronal recovery and mitochondrial dysfunction after a single moderate or mild repetitive blast or blunt injuries.

We have developed a novel 3D human brain-like tissue model to study the molecular mechanisms of injuries. This tissue model, composed of human neurons, astrocytes, and microglia seeded onto silk scaffolds and encased in a gel, allows for reproducible control over cellular composition, environment, and injury. We propose to expose these 3D brain-like cultures to mild repetitive blunt or blast injuries at different intervals and follow them over time using different techniques. This 3D culture system can be replicated many times to provide multiple small experiments that can be exposed to different conditions and grown for different lengths of time. In this way, we will have exquisite control over the exact parameters of the blast and blunt impacts that the cultures are exposed to and the length of time after this exposure. We will compare and contrast the metabolic state of these cultures after either blast or blunt impact injury and examine whether this metabolic state influences the structure of DNA within these cultures. We will also use a metabolic supplement to reverse the detrimental effects on these cultures. These repetitive injuries could have a lasting impact on patients' cognitive and physical performance and the risk of developing neurodegenerative diseases decades after these injuries. The life quality and expectancy of affected military personnel can be severely compromised. We, therefore, wish to identify mechanisms and tools to help identify when the brain is in a “vulnerable state” after multiple injuries.