Adenosinergic Signaling Alters Natural Killer Cell Functional Responses

Area of Science:

• Immunology
• Cancer Biology
• Cellular Metabolism

Background:

• Adenosine, a purine metabolite, suppresses anti-tumor immunity by inhibiting natural killer (NK) cell function.
• Cytokine priming creates distinct NK cell activation states that influence their anti-tumor activity and response to purinergic signaling.
• Understanding these interactions is crucial for developing effective cancer immunotherapies.

Purpose of the Study:

• To investigate human NK cell responses to adenosinergic signaling under different cytokine priming conditions.
• To elucidate the impact of cytokine priming on NK cell activation, function, and metabolic reprogramming in the presence of adenosine.
• To identify potential therapeutic targets for enhancing NK cell-mediated anti-tumor immunity.

Main Methods:

• Human NK cells were primed with distinct cytokines (IL-2, IL-12, IL-15).
• Primed NK cells were exposed to adenosine, and responses were analyzed.
• Key readouts included cytokine expression (IFN-γ), activation markers (NKG2D), signaling pathways (mTOR), and transcriptional changes.
• Metabolic pathways (oxidative phosphorylation, glycolysis) were assessed.

Main Results:

• NK cells primed with IL-12 and IL-15 showed heightened responsiveness to adenosine compared to those primed with IL-2.
• Enhanced interferon-gamma (IFN-γ) production was observed in both CD56bright and CD56dim NK cell subsets.
• Adenosine modulated NKG2D expression and activated mTOR signaling.
• Transcriptional analysis revealed adenosine's role in upregulating immune response genes while downregulating cellular metabolism, including oxidative phosphorylation and glycolysis.
• These effects were dependent on the specific cytokine priming signature.

Conclusions:

• Cytokine priming significantly influences human NK cell responses to adenosinergic immunosuppression.
• Adenosine-induced effects on NK cells are pathway-specific, not a broad inhibition, and depend on priming status.
• Targeting NK cell immunometabolism, guided by priming signatures, holds promise for improving solid tumor immunotherapies.