Date of Award

Fall 2024

Document Type

Open Access Dissertation

Department

Biological Sciences

First Advisor

Katie Kathrein

Second Advisor

Katherine Ryker

Abstract

The hematopoietic compartment is tasked with the establishment and maintenance of the entire blood program in steady-state and in response to stress. Key to this process are hematopoietic stem cells (HSCs), which possess the unique ability to self-renew and differentiate to replenish blood cells throughout an organism’s lifetime. Recent work has illustrated the vast mechanisms involved in regulating stress-induced hematopoiesis, including cytokine-mediated lineage bias, gene signature changes in aged HSCs associated with chronic inflammation, the impact of clonal hematopoiesis and stress tolerance. Inhibitor of Growth 4 (Ing4) has been identified as a critical regulator of HSC homeostasis. We show that Ing4 deficiency promotes gene expression signatures associated with activation, yet HSCs are arrested in G0 and express several markers of quiescence. Thus, Ing4 deficiency promotes a poised state in HSCs, where they appear transcriptionally primed for activation, but remain in a resting state. Expanding this line of inquiry to examine multipotent progenitor cells (MPPs) from Ing4-deficient mice, we observe increased quiescence as compared to WT MPPs, as well as increased activation of Ing4-/- MPPs following exposure to low dose irradiation and 5-FU treatment. Furthermore, in a sorted transplant assay, MPPs from Ing4-deficient mice allowed for robust chimerism and multilineage reconstitution of the hematopoietic program. Taken together, Ing4-/- MPPs may be more agile in transitioning to an activated state than WT MPPs.

Graduate Teaching Assistants (GTAs) facilitate a high proportion of undergraduate courses but have historically received little training in pedagogy. At the University of South Carolina, Teaching Assistant Orientation, GRAD 701 and several Certificate Programs are available to GTAs through the Center for Teaching Excellence to provide professional development and support to meet the wide variety of needs that diverse GTAs experience. From Fall 2020 to Fall 2022, more than 1,000 GTAs entered graduate programs at the University of South Carolina and completed short surveys to capture their confidence in their teaching ability, excitement about their GTA role and concerns at various points during their first semester of graduate school. We found GTAs in STEM degree programs are similarly confident in their ability to complete teaching-related responsibilities and excited about their GTA role as GTAs in non-STEM programs. GTAs, regardless of degree program, express great concern about time and tasks management. Finally, changes in STEM GTAs’ levels of concern show overall similar trends to GTAs in non-STEM programs, though STEM GTAs stand out as remaining especially concerned about promoting a positive classroom environment and communicating with students through the end of the semester. Opportunities for expanded professional development offerings or enacting other supports for all GTAs and specific GTA groups could meaningfully address these concerns.

Rights

© 2025, Georgina Alice Anderson

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