Dr. Armstrong is a developmental biologist, and studies the connection between nutrition/diet and stem cells. She focuses on trying to understand how fat cells in the fruit fly Drosophila communicate with stem cells in the ovary to impact egg production. She is currently a McCausland Fellow, a three-year program for promising early-career faculty at the University of South Carolina.

Dr. Armstrong went to the University of Virginia for her undergraduate degree, followed by Master’s at the College of William and Mary, where she studied the nematode worm C. elegans. She completed her Ph.D. and postdoctoral training at Johns Hopkins University. As a graduate student, she was very involved with MInDs (Mentoring to Inspire Diversity in Science), a group that provides support and outreach to students from underrepresented groups from elementary through graduate school. She continues that investment in mentoring and outreach at all levels of education.

Maintaining all the tissues of the body requires a lot of energy and so trade-offs have to be made, especially in situations where food is scarce. Thus, it makes sense that these self-renewal processes are highly sensitive to diet. In the fruit fly Drosophila melanogaster, it is known that the germline stem cells (GSCs) - the cells in the ovary that make egg cells - grow and divide faster when the flies have a nutrient-rich diet. It was also shown by Dr. Armstrong that disrupting fat cells in the fly “fat body” (sort of equivalent to their liver) causes GSCs to die and the fly to stop ovulating.

So, somehow the fat body communicates to the ovary. In a followup study, Dr. Armstrong compared female flies with a nutrient-rich diet to female flies with a nutrient-poor diet and identified a large number of metabolic pathways that changed depending on diet (based on the abundance of the proteins in these pathways). The nutrient-rich diet increased activity of anabolic pathways that make building blocks that cells need to grow and divide. However, the cells in the fat body are mostly not growing and dividing, so they must be transferring these building blocks to some other cell type.

To ask whether these building blocks were being transferred to GSCs, Dr. Armstrong blocked some of these metabolic pathways. She found that without these building blocks being made in the fat body, most of the GSCs in the ovary died. To show that this was specifically related to diet, she also blocked the ability of the fat body cells to break down fatty acids (which are present at high levels in the nutrient-rich but not nutrient-poor diet) and saw a similar effect.

This study helps to show that there’s an interesting connection between diet, the fat body, and the ovary. However, there are still a lot of details to be fleshed out - which is what Dr. Armstrong is working on now in her lab!