AMPK is a metabolic checkpoint for cDC1 identity and function — ASN Events
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  3. AMPK is a metabolic checkpoint for cDC1 identity and function

AMPK is a metabolic checkpoint for cDC1 identity and function (#163)

Pedro P. Cunha 1 , Inês R. Lopes 1 , Mariana Gadelho-Gonçalves 1 , Ilia Kurochkin 2 3 , Marta Pinto 1 , Margarida Brás 1 , Daniel Oliveira 1 , Hugo Moreira 1 , Lee Dung-Fang 4 , Carlos-Filipe Pereira 1 2 3 5
  1. CiBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
  2. Division of Immuno-Oncology, Lund Stem Cell Center, Lund University, Lund, Sweden
  3. Wallenberg Center for Molecular Medicine, Lund University, Lund, Sweden
  4. Department of Integrative Biology and Pharmacology, The University of Texas, Texas, USA
  5. Science for Life Laboratory (SciLifeLab), Lund University, Lund, Sweden

Metabolic adaptations support immune cell function, and in dendritic cells, mitochondrial rewiring promotes antigen cross-presentation. However, the regulators of this process and the mechanisms by which tumors impair dendritic cell metabolism remain unclear. Here, we used PU.1-, IRF8- and BATF3-mediated reprogramming of fibroblasts and cancer cells into conventional type 1 dendritic cell (cDC1)-like cells to identify targetable metabolic barriers to immunogenic dendritic cell identity and function.

Following reprogramming, cDC1-like cells progressively accumulated mitochondria and increased their oxygen consumption rate, mirroring the metabolic identity of natural cDC1s. We found that PU.1 binds the mitochondrial biogenesis drivers GABPB1 and PGC-1β, whose accesibility increased across reprogramming. Pharmacologic disruption of mitochondria difficulted the acquisition of the cDC1 phenotype, while stimulating oxidative phosphorylation with glucose-to-galactose substitution enhanced reprogramming efficiency. Proteomic and metabolomic profiling of reprogrammed cells revealed a coordinated shift from glycolysis toward oxidative phosphorylation. Reprogramming efficiency was decreased by tumor-like metabolic conditions, including hypoxia, glutamine deprivation and, notably, high glucose, which is intrinsic to the glycolytic phenotype of cancer cells.

We performed an shRNA screen of druggable kinases and phosphatases, identifying AMPK as a top facilitator of cDC1 reprogramming. Silencing of AMPK or its activator CAMKK2 decreased reprogramming, whereas depletion of the phosphatase PP2A or pharmacological AMPK activation enhanced it. Reprogramming increases AMPK phosphosites on TSC2, YAP1, and PFKFB3, linking AMPK kinase activity to mTOR, YAP, and glycolytic programmes. AMPK activation increased mitochondrial mass and function, and production of TNF-α and IL-12 in reprogrammed cDC1s. In vivo, systemic administration of an AMPK agonist synergized with cDC1 reprogramming immunotherapy to recruit intratumoral GZMB+CD8+T cells and reduce mouse melanoma B16 tumor growth. 

Together, these results identify AMPK as an essential metabolic checkpoint for cDC1s identity and function. Pharmacological activation of this checkpoint can overcome tumor-imposed metabolic barriers and potentiate cDC1-based cancer immunotherapies.