Abstract

Natural Killer (NK) cells are innate lymphocytes that recognize virus-infected or malignant cells without prior sensitization. NK cells are activated when germline-encoded receptors identify target cells or through cytokine receptors. Upon activation, NK cells produce pro-inflammatory cytokines, IFN-g, and cytotoxic molecules, such as perforin and granzymes, to activate other immune cells or directly kill target cells. Effector function is closely linked to alterations in cellular metabolism, alongside the recognition of target cells by receptors. This is because metabolites are utilized as co-factors or substrates in epigenetic modifying enzymes, which regulates the gene expression. This mechanism, known as the metabolic-epigenetic crosstalk, has been extensively examined in other immune cells; however, much less is known in NK cells. ATP-citrate lyase (ACLY) is an enzyme associated with the citrate-malate shuttle, which generates cytosolic acetyl-CoA. As acetyl-CoA is a main provider of acetyl groups for lysine acetyltransferase, ACLY plays a major role in the metabolic-epigenetic crosstalk. Previous studies showed that treating ACLY inhibitor (BMS-303141) significantly downregulated the cytokine production in NK cells stimulated with IL-2/12 for 18 hours. In this study, we used a tamoxifen-inducible, NK-specific knockout (KO) mouse model to elucidate whether ACLY regulates cytokine production through modifications in the epigenome. In contrast to the inhibitor study, ACLY KO NK cells showed intact cytokine expression with overnight stimulation. However, IL-15 priming, which is a metabolically demanding stimulation, significantly impaired proliferation, glycolysis, and cytotoxic molecule production in ACLY KO NK cells. Moreover, ACLY KO NK cells showed impaired cytokine expression when stimulated with NKG2D or Ly49H, due to the varying expression of adaptor proteins, DAP10 and DAP12. The expression of genes associated with glycolysis, cytotoxicity, and adaptor proteins was regulated by histone acetylation, demonstrated by CUT&Tag sequencing. Supplementing with acetate, an alternative acetyl-CoA provider, while undergoing IL-15 priming rescued most of the impaired phenotypes of ACLY KO NK cells. In conclusion, this study enhances the understanding of how metabolites rewire epigenetic, which ultimately affects the effector function of NK cells.

Committee Chair

Megan Cooper

Committee Members

Jacqueline Payton; Jonathan Brestoff; Marina Cella; Todd Fehniger

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Immunology)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

8-2-2025

Language

English (en)

Author's ORCID

https://orcid.org/0000-0001-8103-1551

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Available for download on Thursday, July 29, 2027

Included in

Biology Commons

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