Studying the Epigenetic Effects of Cocaine on Mouse Brain


Engineering and Applied Sciences


Assistant Professor of Pharmacology

Project Summary

Dr. Elizabeth Heller’s lab studies the epigenetic effects of cocaine on genes in the mouse brain. Epigenetics is a relatively new field of study in genetics that explains how modifications to DNA can occur due to environment. My lab studies how cocaine can lead to changes in the expression of certain genes in the brain. In the past three months, I have assisted Ph.D. student Marco Carpenter and lab manager Sonia Lombroso in Marco’s Ph.D. thesis studying mice cocaine self-administration.

After finishing my benchwork tasks for the day, I would walk over from Smilow Research Building to the Translational Research Laboratories to handle a cohort of 25 mice. After a period of handling, I would put them in self-administration boxes which model the cocaine-seeking behavior of drug addicts. In these boxes, the more times the mouse spins the wheel, the more cocaine it receives. Thus, these self-administration boxes also reveal how much mice are seeking cocaine. The cohort I tested with Sonia and Marco was also a cohort that was being tested to see if mice can run progressive ratio self-administration. Progressive Ratio is increasing the number of times the wheel must be spun for each additional infusion of cocaine. Our trial run for progressive ratio was successful- our data clearly shows that mice can learn progressive ratio, which is a better paradigm for modeling cocaine addicts.

Running mice in self-administration experiments was the behavior side of Marco’s study. The biomolecular side involved screening CRISPR designed genes on transfected cells grown on cell medium. To quantify mRNA produced by these transfected cells, I had to run qPCR (quantitative Polymerase Chain Reaction) plates and analyze the results. Since mRNA is limited in quantity and is extremely fragile, after the process of extracting mRNA from transfected cells using the RNeasy kit from Qiagen, I had to make cDNA from the mRNA, and the cDNA is what I used in the qPCR plates. Aside from testing transfected cells, I also had to learn how to sac (euthanize) mice from the behavioral experiments and dissect their brains specifically looking for the Nucleus Accumbens (NAc), where the genes of interest affected by cocaine are located.

My summer with Dr. Heller’s lab was very rewarding. Every day was filled with new experiences and new skills to learn or to perfect. This lab allowed me to fully immerse myself in biomolecular sciences and provided me an opportunity to incorporate what I had learned from Biology in high school to the “real world.” It also gave me a chance to be more independent- this summer was the first time I have worked in a lab full-time as a job. I learned skills and techniques that will give me a boost in applying for careers in the biochemical engineering field, as well as skills on how to manage time in a research lab.

Studying the Epigenetic Effects of Cocaine on Mouse Brain