Jacqueline Liu did a stem cell research internship this summer in the laboratory of Gerhard Bauer at the University of California, Davis.
|Jacqueline Liu submitted this photo of adipocytes differentiated from mesenchymal stem cells to our #CIRMStemCellLab Instagram feed|
Specifically in my internship, I worked under the direction of my mentor, Dr. Claus Sondergaard, in the cardiac surgery department at the UCD Medical Center’s Institute for Regenerative Cures. At the time, he was working on developing a patch that could be placed onto the heart after a heart attack, hoping improve the condition of patients instead of merely prolonging the deleterious side effects. By seeding mesenchymal stromal cells (MSCs) onto a decellularized matrix, this patch could then regenerate blood vessels and restore blood flow to the heart, compensating for the loss after the heart attack.
For the project I worked on, I helped with reviewing the mechanisms of actions for these mesenchymal stromal cells, which are still rather mysterious. While we know that they have various healing factors, there is no specific reasoning other than the secreted factors. Even so, which factor? Why? At what levels? The ELISA assay I performed involved IL-8, a human protein often found in saliva. Through this immunoassay, I was able to compare the secretion levels of IL8 between the MSCs that were originally seeded on matrix and those that were grown on plastic. As a result, I found that the cells on matrix emitted almost 40 times as much protein as the ones on plastic, showing another advantage of using a matrix rather than only injecting the cells onto the site of injury. Seemingly, the MSCs prefer the matrix environment with something to bind to rather than floating freely.
Besides this assay, I mainly worked on characterizing MSCs according to the three criteria of plastic adherence, aptitude for trilineage differentiation, and display of certain antigen markers on the cell surface. To do so, I grew MSCs in a plastic flask and examined them under a microscope, thus displaying the cells’ adherence to plastic. Next, I differentiated the MSCs into osteocytes, adipocytes, and chondrocytes to satisfy the criterion of trilineage differentiation. Lastly, I performed flow cytometry to select for certain cell markers, completing the process and confirming that these cells were indeed mesenchymal stem cells and usable for future study.
Although I did not directly interact with in vivo experiments of MSCs on matrix or in the heart, I performed many of the basic duties needed before using these stem cells during in the large animal model or clinical trials. It is important to first characterize the cells and examine ones from different donors in order to consider which cells may be better for trials and hopefully treatments in the future. By doing these assays and characterizations I feel like I was able to contribute to the overall project and make a difference, though most likely minute, in the stem cell field.
Jacqueline sent us this video of her experience: