RESUMO
Fasting is associated with improved outcomes in cancer. Here, we investigated the impact of fasting on natural killer (NK) cell anti-tumor immunity. Cyclic fasting improved immunity against solid and metastatic tumors in an NK cell-dependent manner. During fasting, NK cells underwent redistribution from peripheral tissues to the bone marrow (BM). In humans, fasting also reduced circulating NK cell numbers. NK cells in the spleen of fasted mice were metabolically rewired by elevated concentrations of fatty acids and glucocorticoids, augmenting fatty acid metabolism via increased expression of the enzyme CPT1A, and Cpt1a deletion impaired NK cell survival and function in this setting. In parallel, redistribution of NK cells to the BM during fasting required the trafficking mediators S1PR5 and CXCR4. These cells were primed by an increased pool of interleukin (IL)-12-expressing BM myeloid cells, which improved IFN-γ production. Our findings identify a link between dietary restriction and optimized innate immune responses, with the potential to enhance immunotherapy strategies.
Assuntos
Jejum , Células Matadoras Naturais , Camundongos Endogâmicos C57BL , Animais , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Camundongos , Humanos , Neoplasias/imunologia , Medula Óssea/imunologia , Medula Óssea/metabolismo , Camundongos Knockout , Interferon gama/metabolismo , Interferon gama/imunologia , Baço/imunologia , Baço/metabolismo , Imunidade Inata/imunologia , Interleucina-12/metabolismo , Interleucina-12/imunologia , Receptores CXCR4/metabolismoRESUMO
Natural killer (NK) cells are a vital part of the innate immune system capable of rapidly clearing mutated or infected cells from the body and promoting an immune response. Here, we find that NK cells activated by viral infection or tumor challenge increase uptake of fatty acids and their expression of carnitine palmitoyltransferase I (CPT1A), a critical enzyme for long-chain fatty acid oxidation. Using a mouse model with an NK cell-specific deletion of CPT1A, combined with stable 13C isotope tracing, we observe reduced mitochondrial function and fatty acid-derived aspartate production in CPT1A-deficient NK cells. Furthermore, CPT1A-deficient NK cells show reduced proliferation after viral infection and diminished protection against cancer due to impaired actin cytoskeleton rearrangement. Together, our findings highlight that fatty acid oxidation promotes NK cell metabolic resilience, processes that can be optimized in NK cell-based immunotherapies.