What have your Ph.D. studies focused on?
“My Ph.D. studies have focused on the regeneration of salivary gland, which is an organ that is responsible for the production of saliva in our mouths. Salivary glands play an important role in our body, keeping moisture in our mouths, helping us to swallow and digest food, and aiding in speech. Like any other part of our bodies, things can go wrong with them. Dry mouth, or xerostomia, is a group of incurable conditions caused by aging, radiation/chemical exposure, or aberrant inflammation in the salivary glands. These are widespread conditions where the lack of saliva production causes symptoms like burning sensations in the mouth, sticky saliva, oral fungal infections, difficulty speaking, swallowing, and so on.
During my thesis, we evaluated whether cell-derived strategies, in this case, extracellular vesicles (EVs) could be a potential new therapy to repair salivary gland injury and restore function following radiotherapy or in autoimmune diseases. EVs are membrane-bound lipid bilayer vesicles secreted by cells or body liquids, with a strong capacity to deliver essential information between cells. Secreted EVs from stem cells have become a hot topic with high research and clinical interest since they avoid concerns about the risks associated with directly injecting stem cells into the human body.
In Papers I and Paper III of my thesis, we examined stem cell-derived therapies' potential on two most common conditions of xerostomia, which are acute irradiated and chronic immune dysregulation-caused salivary gland hypofunction. Then, to translate the knowledge from Paper I and III, a new model that could use human samples needed to be found, this is Paper II, in which we developed a bioengineered model for salivary gland disease that can be used to evaluate regeneration and test pharmaceutical trials (like EV therapy). We also developed advanced light sheet fluorescence microscopy imaging for it. Lastly, we developed a histology process without xylene and a more objective histological evaluation (via scoring system) in Paper IV. This will not only help us better understand animal research that is normally done today, but also help in finally translating these findings to treatments for human diseases and lead to more timesaving and accurate histological verification in the future clinical scenario.
Overall, this work has led to the development of a set of in vitro and in vivo tools to research salivary gland diseases and test available treatments. We hope this PhD project will contribute to improved knowledge for salivary gland research and evaluation of potential new therapies such as cell-free and tissue engineering treatments in the future,” explained Dong.
Can you tell us more about the cover of your thesis?
“For the front cover, I chose an image based on the light sheet-based microscopy imaging technique that we used. The reason why we wanted to use this, is that compared to confocal microscopy imaging, light-sheet microscopy imaging offers fast, high resolution, true volume, and in-depth imaging with low photobleaching, minimal phototoxicity. It also can create images of transparent tissues at cellular and subcellular levels at high spatial and temporal resolutions and the ability to generate serial optical tissue sections that allow for 3D reconstruction of tissue structures.
All of these unique capabilities of light sheet microscopes allow for the acquisition of challenging specimens and works well for tissues that are very thick. We just need to perform optical clearing to make the tissue transparent and produce an image based on the whole tissue. This image is the achievement of our endeavor in optimizing the protocol to do this light sheet fluorescence microscopy on our precision-cut salivary gland slices. So, these are the reasons why I choose this for my front cover,” noted Dong.
How did you end up doing a Ph.D. at Lund Stem Cell Center?
“My five years of undergraduate and three years of graduate studies in China, changed my ideas and shaped my choices, setting me down this path. I studied oral medicine in the beginning with the intention to study oral surgery. In my clinical rotations, I met patients with oral cancer, experiencing the dry mouth symptoms after radiotherapy. The empathy of human beings is hard to be removed from memory. I admit that I had many unforgettable moments during my clinical training, but this patient with xerostomia post-radiation really touched me a lot and I couldn’t let it go for a long time.
So, I decided to continue studying this by studying abroad with a Ph.D. program at Nagoya University where my Ph.D. started. I learned about how stem cell free therapies could be a way to help these patients while preserving or even giving them a better quality of life. Then I participate a joint degree program, which allowed me to discover Dr. Darcy Wagner's and her lab which studies bioengineering to fabricate artificial organ in lab. Something that I was super interested in even before I went to Nagoya University. So, I came to Lund University to study with Dr. Darcy Wagner and learn about bioengineered salivary glands. This became a joint study between Nagoya University and Lund University (the Lund Stem Cell Center) from June 2021 to September 2022. Now I am back in Nagoya, and preparing my thesis defense this February,” explained Dong.
What have you found the most enjoyable during your Ph.D. studies?
“I think the most enjoyable part has been working in such professional lab for and working with nice research members during this study process. I was delayed by the pandemic and had to shorten my study period in Lund. For my supervisor, Dr. Darcy, this made it more difficult for her to offer assistance in my Ph.D. But Dr. Darcy is a very professional researcher and quite nice and generous person. She often gave me encouragement and I enjoyed this teaching style based on trust. I think this is something we lack in our educational system here in Asia. She has also built a good, scientific lab environment. So, I could also learn and work under a well administrated and organized lab, which also became the foundation for my achievements during the Ph.D. process. So, experiencing these different kind of teaching methods from supervisors, and working habits from co-workers in different backgrounds, also the running styles between different labs, was an enjoyable aspect of this study period” highlighted Dong.
What has been the most challenging aspect?
“The challenging part, I think relates more to the time limit of joint study and Lund University’s graduation requirement to have four papers for a Ph.D. thesis. I think for Ph.D. students, this pressure might in some ways ruin their interest in academia. So, Ph.D. students need to have more efficient solutions to collaborate with others and be creative about how their Ph.D. study can be evolved and navigated to reach the graduation level, especially during the unusual time between 2019 to 2022. I think creativity to find replaceable types of studies to face the lack of animal or human samples is needed, which is also somethings that pandemic enabled us to think about more,” noted Dong.
What are your plans following your Ph.D. defense?
“Right now, the future is quite open, with many possibilities to consider. Different places have their unique occupational culture. I’ll see what exciting things the future may hold,” reflected Dong.
Any tips or advice for future Ph.D. students?
“Yes, I have at least one. In the first year, after admission to a Ph.D. project, Ph.D. students have to write their individual study plans. This is a very good chance for them to improve their understanding and discuss more with their professors about their whole Ph.D. overview. Additionally, once every year, this individual study plan will be asked to be updated or modified. So, each time it's modified, I recommend summarizing your thoughts based on your own research progress as this will help to arrange the later study quite well. So, if they seize the chance created by writing and modifying their individual study plans and put a good amount of effort into creating a great and feasible study plan, this will set them on the right path right from the start all the way to the end. So future Ph.D. students should utilize this opportunity to be sure to summarize critically and communicate effectively and react responsibly to the feedback given from their supervisors and team-members as well,” concluded Dong.