Polyamine sequestration of 2′3′-cGAMP constrains intercellular transmission and STING engagement to subvert antitumor immunity
Yunjin Ma, Chunyuan Zhao, Jiacheng Guo, Yue Fu, Wei Wang, Jiangong Zhang, Kun Zhao, Xiangbo Meng, Zhongshang Yuan, Chengjiang Gao, Mutian Jia, Ying Qin, Hui Song, Wei Zhao
Yunjin Ma, Chunyuan Zhao, Jiacheng Guo, Yue Fu, Wei Wang, Jiangong Zhang, Kun Zhao, Xiangbo Meng, Zhongshang Yuan, Chengjiang Gao, Mutian Jia, Ying Qin, Hui Song, Wei Zhao
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Research Article Immunology Metabolism

Polyamine sequestration of 2′3′-cGAMP constrains intercellular transmission and STING engagement to subvert antitumor immunity

Abstract

The cyclic dinucleotide 2′3′–cyclic guanosine monophosphate–adenosine monophosphate (2′3′-cGAMP) serves as a central immunotransmitter that propagates stimulator of interferon gene–dependent (STING-dependent) innate immunity across tissues; however, how microenvironmental metabolites regulate its spatiotemporal dynamics remains unknown. Here, we identified polyamines (spermine and spermidine) as critical rheostats controlling 2′3′-cGAMP functionality. Mechanistically, polyamines sequestered 2′3′-cGAMP into polymer-like aggregates, blocking intercellular propagation and suppressing intracellular STING activation by reducing ligand-receptor binding affinity. Deficiency of spermidine and spermine N1-acetyltransferase 1 (SAT1), the rate-limiting enzyme in polyamine catabolism, elevated polyamine levels to entrap extracellular 2′3′-cGAMP and inhibit STING activation. Synergistic administration of endogenous 2′3′-cGAMP with SAT1 stabilizer N1,N11-diethylnorspermine restored 2′3′-cGAMP bioavailability and STING signaling, facilitated type I interferon responses to reprogram immunologically suppressive tumors into immunologically active states and enhanced tumor clearance. Our study established polyamine–cGAMP interactions as a critical spatiotemporal regulatory mechanism for tissue-level immunity, providing a unified model for metabolite-mediated cyclic GMP-AMP synthase–STING (cGAS-STING) regulation across diseases.

Authors

Yunjin Ma, Chunyuan Zhao, Jiacheng Guo, Yue Fu, Wei Wang, Jiangong Zhang, Kun Zhao, Xiangbo Meng, Zhongshang Yuan, Chengjiang Gao, Mutian Jia, Ying Qin, Hui Song, Wei Zhao

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Figure 1

Spermine and spermidine selectively inhibit 2′3′-cGAMP propagation.

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Spermine and spermidine selectively inhibit 2′3′-cGAMP propagation. (A) ...
(A) In vitro extracellular 2′3′-cGAMP–induced STING activation assay method. Images were created with BioRender. (B) In vitro STING activation assay measured as the amount of IFN-β secretion from PMs pretreated with a 10 μM endogenous metabolite library for 1 hour, followed by 2′3′-cGAMP stimulation as in (A). Fold changes were calculated as IFN-β production in metabolite-pretreated samples versus untreated controls upon 2′3′-cGAMP stimulation. The R package Enhanced Volcano was used to visualize endogenous metabolites regulating STING activation. (C) In vitro 2′3′-cGAMP uptake assay measuring intracellular 2′3′-cGAMP in PMs pretreated with the top 20 IFN-β secretion-inhibiting metabolites from (B), followed by 2′3′-cGAMP stimulation. Fold changes were calculated as 2′3′-cGAMP entrance in metabolite-pretreated samples versus untreated controls upon 2′3′-cGAMP stimulation. (D) Images and quantified fluorescence intensity of PMs pretreated with 10 μM polyamines for 1 hour and subsequently stimulated with 2′3′-cGAMP-Cy5 for 4 hours. Scale bars: 2 μm. (E–L) ELISA analysis of CDNs entry (E–H), cytokine expression (I and J), qPCR analysis of cytokines (K), or IB analysis of indicated antibodies (L) in PMs pretreated with polyamines, stimulated with CDNs. (M and N) ELISA analysis of 2′3′-cGAMP entry and cytokines expression in Cgas–/– mouse PMs incubated with lysates from doxorubicin-treated B16F10 cells for 24 hours. (O–Q) ELISA analysis of IFN-β secretion (O and P) or IB analysis (Q) in mouse PMs pretreated with polyamines or N1-acetylpolyamines, stimulated with CDNs. Statistical significance was determined using unpaired 2-sided t test, and adjustments were made for multiple comparisons in C–K and M–P. The data are shown as the mean ± SEM. *P <0.05, **P <0.01. Similar results were obtained from 3 independent experiments. Put, putrescine; Spm, spermine; Spd, spermidine; US, unstimulated.