Hyuna Lee, working under Professor Jeon, used a unique microfluidic platform to perform her biological research. Using this platform, she was able to culture neurons to isolate the axons from the soma, so that she could observe GFP-tagged mitochondrial movement in the axons. Through her research experience, Hyuna developed an appreciation for reading papers describing how other researchers conducted their studies. She found the constant friendship and support of the people in her lab to be particularly valuable. Hyuna intends to attend graduate school to further develop the passion she has developed for innocent lives shortened by incurable diseases.

Neurodegenerative diseases, such as Alzheimer’s disease, lead to permanent disabilities in muscular movements, memory and dementia. Mitochondrial transport is closely linked to neuronal function. Mitochondrial trafficking along microtubules delivers energy in the form of adenosine triphosphate (ATP), which is necessary for signal transmission and sustaining viability. Controversy remains regarding the direction and mechanisms by which mitochondria move in aging and diseased neurons. It is unclear whether axonal transport impairment is due to mutations in mitochondrial DNA or other cytoplasmic factors. We used a microfluidic culture platform to analyze mitochondrial trafficking patterns in axons by transfecting neurons with Mito-GFP and observing them under time-lapse microscopy to analyze differences in mitochondrial morphology, movement and interaction. Elongated mitochondria in soma and dendrites were less motile but moved steadily. Mitochondria in axons generally had short ovular shapes with rapid bidirectional movements and varying speeds. Many clusters of mitochondria were found in locations that required large amounts of ATP. We also observed mitofusion or mitofission, which may be indicators of neuron survival or death, respectively. This research is a first step in developing a model to closely reflect neuronal mitochondrial trafficking patterns.

Noo Li Jeon Henry Samueli  School of Engineering

Understanding the relationship between mitochondrial axonal transport and neurodegenerative diseases such as Alzheimer’s, Huntington’s and Parkinson’s is important in the search for successful treatments for these diseases. In tracking mitochondrial movement, it is important to distinguish the morphology of the dendrites and axons. The microfluidic culture platform Hyuna Lee used in her research establishes this distinction, providing a clear look at trafficking patterns throughout the neuron. The results of this study offer a better understanding of mitochondrial transport, a potential first step toward complete elucidation of the pathology of neurodegenerative diseases. Hyuna’s work demonstrates the success that can be achieved by undergraduate students who passionately devote themselves to their research.