ORCID
https://orcid.org/0000-0003-3735-2643
Date of Award
9-1-2023
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Natural killer (NK) cells are innate lymphoid cells that play important roles in antiviral and antitumor responses through their cytotoxicity mechanisms and the ability to modulate immune responses through production of cytokines such as IFN-g. NK cells are able to execute these responses rapidly and without prior sensitization due to their germline-encoded receptors. Recent work in the field of immunometabolism has highlighted the impact that changes in cellular metabolism can have on immune cell function, including NK cell effector functions. Our lab has previously reported activation-specific metabolic requirements for IFN-g production by resting murine NK cells in vitro, which IL-15 priming, abrogates. To investigate how IL-15 priming alters the requirements for IFN-g production, we assessed chromatin accessibility, ITAM signaling, and transcriptional changes. We found that IL-15 priming leads to a switch to transcriptional regulation of Ifng in response to activating receptor engagement, similar to cytokine-stimulated resting NK cells and in contrast to the translational regulation observed in activating receptor-stimulated resting NK cells or NK cells cultured for the same duration, in low dose IL-15. This switch in Ifng regulation in the primed cells was not due to chromatin accessibility changes in the Ifng locus or changes in ITAM signaling. Transcriptional regulation of Ifng was associated with a common signature of Myc target upregulation. To determine the potential role of Myc in IFN-g production, two approaches were used to manipulate c-Myc: a pharmacological approach to inhibit c-Myc transcription factor activity, and a genetic model to acutely delete c-Myc. While the pharmacological approach suggested c-Myc acts as a transcription factor to regulate Ifng transcription in primed NK cells, the genetic approach revealed that c-Myc is in fact not required for Ifng transcription. In summary, this work demonstrates that IL-15 dose and culture time can dramatically alter chromatin accessibility and regulatory networks in murine NK cells, cautioning that interpretation of NK cell studies should take into account culture conditions. Furthermore, it advances our understanding of IFN-g regulation in murine NK cells.
Language
English (en)
Chair and Committee
Megan Cooper
Recommended Citation
Cimpean, Maria, "IL-15 and IFN-g regulation in murine NK cells" (2023). Arts & Sciences Electronic Theses and Dissertations. 3138.
https://openscholarship.wustl.edu/art_sci_etds/3138