Meegan Sleeper, Graduate Research Assistant, Biochemistry Graduate Student
My research focuses on characterizing rare cell populations from bone marrow and peripheral blood with a specific emphasis on their progressive dysfunction in the aging process. Much of this work centers around hematopoietic stem cells (HSC). HSCs are residents of the bone marrow and give rise to all blood cells. The age-associated dysfunction of HSC and their progeny is a hallmark of an aging phenotype. The study of primary cells from the bone marrow presents several technical hurdles, ranging from techniques for cultivation outside of the body, to optimizing target cell harvesting, enrichment, and characterization. These challenges are compounded when we consider that there are subtle, yet often significant differences, in the behavior of blood cells between species. One of my favorite projects at Ichor involves optimizing the detection of rare engrafted donor cells in recipient mice, which is an important part of understanding the effects of transplanting donor cells to restore hematopoietic homeostasis in aged animals. There are many different models that can be used to track donor cells which only require a small quantity of peripheral blood for analysis. The donors in these models typically have a different phenotype from the recipient (e.g. GFP expression or unique surface antigens). This allows for donor and recipient cells to be distinguished in downstream analysis, enabling engraftment to be tracked over time. Flow cytometric analysis is a common (and my preferred) way to quantify the number of donor cells that are circulating in recipient blood. Not only can we track basic engraftment, but these cells can be further characterized post engraftment by looking at key surface markers, which can shed light on their function and activity after transplantation.