UCLA Ajijola Lab, Los Angeles, CA
This summer, I had the opportunity to intern at UCLA’s David Geffen School of Medicine in Dr. Ajijola’s neurocardiology lab. The focus of the lab is on the application of neuromodulatory therapies for treating patients with minor and severe cardiac arrhythmias and recognizing biomarkers of autonomic function capable of identifying arrhythmia and sudden death risk.
As someone who is not a biology major, it was difficult in the beginning trying to learn all the physiological terms and getting used to the routine of basic translational research. During the first couple weeks, I had the opportunity to get exposure to all the different projects being conducted on topics that spanned from understanding how cardiac sympathetic innervation remodels in response to ischemic or nonischemic cardiac injury to intra-ganglionic neural recordings and targeted induction of human disease models for experimental study. I was honestly mind-blown by the amount of projects going on at the same time and how Dr. Ajijola, in addition to seeing and treating his patients, was able to oversee all of them. At first, I was a little intimidated because I was the only undergraduate student in the lab, but all the graduate students and research assistants were extremely welcoming and became wonderful mentors for me throughout the entire internship.
Starting from the third week, I was given my own independent summer project, which was very nerve-wracking but also super exciting. My project focused on exploring the possible roles of neuropeptide Y (NPY). Past research has shown that NPY may be pro-arrhythmic by directly influencing ventricular electrophysiology by acting on the Y1 receptors on the ventricular myocytes, influencing electrophysiology and predisposing to ventricular arrhythmias. Sympathetic neurotransmitters like neuropeptide Y can be released in addition to noradrenaline. Targeting NPY receptors pharmacologically may therefore be a useful therapeutic strategy both to reduce heart rate and to prevent arrhythmias in the setting of heart attacks and chronic heart failure. While there are multiple Y receptors, past research has shown that the Y1 receptor is 270 times more receptive for NPY. My project focused on figuring out the correct dosage of BIBO3304, a highly selective Y1 receptor antagonist, through behavioral testing on mice. By seeing its effect on the heart rates of mice, we can better understand if NPY is just a mere biomarker or a causative agent of a failing heart, allowing us to further investigate therapeutic strategies both to reduce heart rate and to prevent arrhythmias.
In trying to figure out the correct dosage range of BIBO3304, we based our experimental protocol in administering the BIBO3304 off on past literature. Since NPY is released when the mouse is in a stressful condition, it was critical that the experimental procedure did not create unnecessary stress on the mice. As a result, the least invasive procedure we found was to train the mice to eat jelly, and record their ECG to monitor how their heart rate would change after taking BIBO3304. I was able to learn how to analyze mice ECG, and it was very interesting to see the similarities and differences in the patterns of a mice ECG versus a human ECG.
While I was very lucky to have the opportunity to have my own project, it was incredibly frustrating especially in the first phase of my experiment. By blocking the Y1 receptor, we expected the heart rate to decrease since the only other pathway possible for NPY to reach the cardiac myocyte is through the Y2 receptor in the vagus nerve, which decreases acetylcholine and the heart rate. However, during the first couple weeks of administering BIBO3304, we continued to see a pattern of increased heart rate across all the mice. At first, I changed the experimental procedure by increasing the dosage of the receptor antagonist because I thought the dosage wasn’t high enough to take effect. However, that didn’t change the unexpected result, which made me reassess the current experimental protocol: the sugar in the strawberry jelly or the poor absorption of BIBO through oral administration. So I decided to change the method of administering BIBO3304 through an intraperitoneal injection to ensure proper absorption of the medication. We tried many dose ranges, but confirmed that the 20mg/kg dosage was the correct dosage to administer.
We also had weekly lab meetings where I was able to practice my presentation skills and sum up our findings each week. Dr. Ajijola also gave us a chance to test our knowledge by throwing quick questions at us while we presented. While it was embarrassing at times to stumble over our thoughts, he taught me so much and made sure that I fully understood the concepts underlying my projects.
During my time at the internship, I was fortunate to be able to attend the 11th Congress of the International Society of Autonomic Neuroscience (ISAN) held at UCLA in July. This annual meeting provides a forum for autonomic neuroscience investigators from around the world to gather, discuss, and share ideas on a broad range of topics related to the autonomic nervous system. It was an incredible experience for me to actually see the relevance of my work through this meeting, and I was able to meet many renowned scientists from all over the world who wrote the papers I had to read in preparation for my project. Specifically, I read many papers by Neil Herring, a scientist from London, and it was very captivating to hear his research in person and actually be able to talk to him.
After my finishing my first project, I was assigned to start three new projects during my last two weeks of the internship. While it was a lot to try to balance all three projects at once, it gave me a lot of confidence that Dr. Ajijola believed in me to be able to handle this task. It allowed me to apply my skills that I learned from the first project and made me realize how much more prepared I have become for future research opportunities. One of the new projects is a continuation of my first project focusing on if BIBO has an effect on the mortality of mice with heart failure. Using the 20mg/kg dose I found in my first project, I administered this dose of BIBO3306, recorded the mice’s ECGs every week, and kept track of when the mice die to see its effects. Since I was only there for two more weeks since starting this project, I was not able to see the end result and effects, but am looking forward to hearing about the results in the next couple weeks.
My second project looked at the effects on heart rate if we prevented the acetylcholine release using a selective Y2 receptor antagonist, BIIE0246, in the parasympathetic pathway. Since acetylcholine is known to decrease heart rate, we hypothesized that by blocking the Y2 receptor which normally triggers acetylcholine release, we will be able to increase heart rate. The experimental protocol for this study was similar to that of my BIBO3306 project since we were trying to determine the dose range of BIIE0246. I was unable to figure out the correct dosage, but I am very hopeful that my fellow colleagues who take on the project after I leave will.
My final project focused on the sympathetic nervous system, which can affect heart rate, cardiac contractility, and resistance in vessels. The activity of SNS nerves are caused by a complex neural network including neurons and glia. The Gq G protein-couple receptor (Gq-GPCR) in the central nervous system regulates neuronal activity, but it is unclear how its signaling affects the sympathetic neurons or contributes in cardiovascular functions. In order to investigate whether Gq-GPCR activation modulates the regulatory effect of the SNS on the heart, we used mice expressing the Gq-coupled DREADD (designer receptors exclusively activated by designer drugs) selectively in GFAP+ glia (hM3Dq). We expected to see an increase in heart rate after the CNO administration for hM3Dq+ mice and no change for hM3Dq- mice. While we were unable to see an increase in heart rate within the fifteen minute span after the CNO administration, we saw an increase in the hM3Dq+ mice’s heart rates before we started the CNO administration and after.
Going into this internship, I was a little skeptical on whether or not research or the MD/Ph.D. route would be something I’m interested in. However, after this internship, I was surprised to see that I enjoyed my time in research. While I realized that research could potentially be my passion for the future, I am not sure if research including behavioral testing would be for me since I tend to develop attachments to the animals I work with. This has made me want to potentially explore other fields of research such as clinical research and other types of research potentially focused on psychology, my major.
My wonderful experience was only possible because of the Alumni Sponsored Internship Program, and I thank the Class of 1972 and the ’68 Center for Career Exploration for providing me with this opportunity. It has not only allowed me to develop useful skills, but also has allowed me to further pursue my interest in the medical field.