From mouse to man, towards a cure for autoimmune diseases
FUNDED: JANUARY 2020
FUNDED BY: the generosity of Barbara Donnell, Bill Passey & Maria Silva,
and 2019-20 Various Donors
What was the goal of your SPARK project?
More than 50 million Americans suffer from autoimmune diseases, and these numbers are rising at alarming rates. We know that patient immune cells damage healthy organs in autoimmune disease, but scientists don’t understand exactly why these immune cells go off course. The thymus is where the body sorts helpful T cells from harmful T cells. T cells that recognize healthy tissue should be educated not to cause autoimmune disease, but in some cases this education is disturbed and harmful autoreactive T cells are the result. We’ve learned a lot about this process by studying mouse models, but we need more tools to see T cell receptor (TCR) selection in action. With my SPARK award, I worked to set up an organoid culture system for human T cells, starting from stem cells isolated from human thymus samples. My hope is to use this system to interfere during human T cell development and assess the functional profile and TCR repertoire of mature T cells.
“Model systems are crucial scientific tools on the road to novel therapeutics. In order to take the next step toward our goal of ‘Life Without Disease,’ we need to take our findings into human studies, which is what I hope to do with this SPARK project.”
Pivoting during a pandemic
I had just started quality control of all my reagents to set up the organoids when the pandemic began and the Institute restricted access to scientists not working on COVID-19 research. So I had to freeze all the cell lines down again and wait until my access to the lab would be restored. Growing these cultures takes about 30 days, and the cells need my attention at least every three days, so it is a commitment to start a culture and access to it is critical. Because of this, I had to wait until the Institute had more clarity on the internal COVID-19 testing program that would allow employees to access the labs more regularly in order to run experiments. In addition, throughout the 2020-2021 school year, I had two elementary school-age children at home doing virtual school, which made planning harder since someone had to stay at home with them to supervise them while also trying to work from home. Once pandemic restrictions were relaxed enough for my children to attend summer camps and have full-time care in 2021, I could get started on long-term cultures, titrate my inhibitors and test which time points would be best for the actual experiment to generate the cells used for single cell sequencing. I’m grateful that the extensions granted to my cohort allowed me the opportunity to run these experiments and continue my project once our work-home routines normalized again.
SPARK project results:
We used an organoid culture system for human T cells, starting from stem cells, and tested if we could mimic the genetic models of mouse T cell generation by adding pharmaceutical compounds to the culture. We used single cell RNA sequencing to compare the nature of the generated T cells with those from normally-developed T cells. In addition, we wanted to get an idea of the ability of the cells to recognize a human body’s own tissue and organs. For this purpose, we obtained the genetic sequences of the key structure of the T cell that recognizes its target.
We found that the use of a pharmaceutical compound (2-DG) during human T cell organoid culture mimics the genetic defect we observed in mouse models. This means that it is likely that similar mechanisms underlie the generation of functional T cells in humans and in mice. Identifying how we can manipulate these processes will significantly boost our knowledge of the pathways leading to autoimmunity and will aid in the design of effective new strategies to cure or even prevent autoimmunity.
What’s next for this project?
I will build on these data and perform in-depth analyses of the TCR sequences we found. I will need to score the self-reactivity computationally and answer the question of whether inhibiting glycolysis during beta-selection alters the recognition of self-antigens. When I have this data, I will work with my Principal Investigator, Hilde Cheroutre, Ph.D., to add it to the paper I hope to prepare and submit to journals in 2022. Additionally, if the hypothesis proves right, this will be important preliminary data to submit an R01 grant to the National Institutes of Health on this project.
I’m also excited to share that Dr. Cheroutre and I will continue to build on this project together, thanks to a $400,000 grant from Praespero (a Canadian charity focused on funding autoimmune disease research) received in fall 2022.
What’s next for Greet?
For me personally, I really want to focus now on elaborating on the mechanism behind our findings in the mouse models. The more detail we can uncover, the better our options for publishing a paper or securing follow-on funding will be, and my options for my future career will depend on that. I must admit that when I joined LJI, my aspiration was to start my own lab one day and contribute to the scientific fields of T cell function and how they relate to autoimmunity and cancer. But with time, and especially having lived through the pandemic, I can see myself achieving professional goals in a company setting as well. Most importantly, I want to eventually transition to a leadership scientist position that will utilize my medical and scientific background to contribute to moving the health sciences forward.