Hello! My name is Madison Cornwell, and I am an undergraduate researcher and CNSI EUREKA Intern currently working in the lab of Dr. Kenneth Kosik through the Neuroscience Research Institute at UCSB.
During my freshman year, I determined to break through the obstacles and fierce competition restricting many students from becoming an integral member of a research team. After dabbling in a Marine Biology Lab in my first quarter, the EUREKA internship empowered me to obtain a position in a cutting edge medical research lab.
It only took a few days to realize I had found my passion.
Alzheimer’s (AD) is a neurodegenerative disease characterized by both intracellular neurofibrillary tangles (NFTs) and extracellular aggregates of beta-amyloid found within specific regions of the brain including the hippocampus, which is responsible for memory. In an Alzheimer’s patient, hyperphosphorylated tau detaches from microtubules in the neuronal axon and accumulates within the cell, forming NFTs that cause neuron malfunction and eventual cell death. Developing a drug that would target these aggregates of tau could improve the lives of millions of Alzheimer’s patients worldwide.
During the winter and spring quarter of my freshman year, my research focused upon one candidate of interest; the phenothiazine methylene blue (MB) that had been shown to disintegrate tau tangles in vitro. To test the viability of this interaction in an in vivo model, Israel and I studied the effects of MB upon NFTs using a transgenic AD mouse model. Through intraperitoneal injection, we treated mice with different concentrations of MB daily for one week. We then collected the brain tissues and used fluorescent immunohistochemistry to detect NFTs in the hippocampus. Intriguingly, when viewed under the microscope, we observed that the MB treatments seemed to actually increase the fluorescent signal of hyperphosphorylated tau. Quantification of the intensity of fluorescence in histological samples of treated and untreated mice reinforced this visual observation. Through this experiment, our hypothesis, stating that Methylene blue decreases levels of hyperphosphorylated tau in vivo as it does in vitro, was proven incorrect. Concluding in early June, this project left me simultaneously curious, confused, and eager to investigate as I boarded the Amtrak train for a summer with my family.
Returning in the fall, Israel and I discussed published research exploring the different roles of Methylene Blue. We discovered that it had been identified as an inhibitor of Hsp70 ATPase activity. Hsp70 is part of multichaperone complex consisting of Hsp70 and Hsp90 connected by the protein Hop. Within this complex, Hsp70 is the chaperone protein responsible for the disposal and degradation of damaged or defective proteins through interaction with CHIP (Carboxyl-terminus of Hsp70 Interacting Protein) an E3 ubiquitin ligase. Our data illustrated an increase in hyperphosphorylated tau with the addition of Methylene Blue. If Methylene blue inhibits the activity of Hsp70 in vivo, and this inhibition of Hsp70 increases the level of hyperphosphorylated tau within the neurons of the hippocampus, then this interaction would explain our results from the spring.
Following this conversation, we decided to test our adjusted hypothesis by designing a new experiment to observe the effect of an Hsp90 inhibitor upon the level of hyperphosphorylated tau within the hippocampus of the same transgenic AD model mice. We chose the drug Celastrol.
Today marked the last of 15 daily injections of 3xTg mice with different concentrations of Celastrol. After so many days of treatment, I am feeling pretty confident with the process of IP injections. We are wondering whether we extended the treatment too long, however. By the last few days, the area of injection seemed to thicken with scar tissue, making treatment more difficult. Tomorrow Israel and I will perform heart perfusions with PBS to clear the brain of blood, and then extract and the brains to be soaked in paraformaldehyde. This forms methylene bridges or cross-links between the peptides (chains of amino acids forming proteins) of the tissue so that they are firm and ready for vibratome slicing on Thursday.
I am the Resident Assistant of the Women in Science and Technology Residence Hall at UCSB. While heading to dinner today, I realized I spent the entirety of my one-on-one session with the Assistant Resident Director (who was a Business and Economics major) explaining my research project and answering all his questions. That is when you know you are doing what you love.