Uncoupling of STING Accumulation and Activation upon Chromosome-Derived Extrachromosomal Circular DNA Formation
- 1Kyoto University
Abstract
The innate immune system maintains cellular homeostasis by recognizing cytosolic nucleic acids. While the cGAS-STING pathway is well characterized in detecting non-self-DNA, its response to self-DNA originating from the host nucleus remains unclear. Extrachromosomal circular DNA (eccDNA), a form of self-DNA often enriched in cancer, has been implicated in immune modulation, yet its ability to activate cGAS-STING remains unresolved. Here, we developed a Cre-loxP-based eccDNA reporter system, where Cre-mediated eccDNA formation triggers expression of the fluorescent protein mCitrine, enabling time-resolved, single-cell analysis of chromosome-derived eccDNA dynamics and STING activation. Using an mRuby3-STING reporter, we found that low-dose plasmid transfection induced STING activation, as evidenced by modest STING accumulation and downstream cytokine induction. Cells carrying chromosome-derived cytosolic eccDNA also showed a modest, cGAS-dependent accumulation of STING. However, this accumulation was uncoupled from detectable STING-Ser366 phosphorylation or induction of downstream cytokines. These findings indicate that chromosome-derived eccDNA does not drive detectable STING signaling under the conditions tested, and that STING accumulation and its activation are mechanistically separable steps. This work provides a foundation for understanding the immunological roles of eccDNA in genome instability and cancer.
Related
- Extrachromosomal circular DNA formation follows a 10.5-bp periodicity reflecting the minor groove orientation around nucleosomes
- Sex chromosome and gonadal regulation of cardiac myofibroblast activation decoupled using mechanically tunable hydrogels and the Four Core Genotypes model
- Nrf2 Activation Induces Fibroblast Senescence and Promotes Melanosome Accumulation in a Fibroblast-Keratinocyte Co-Culture Model
- 3′‐UTR Hypermethylation and ABA Signaling Coordinate Transcriptional Activation of SWEET14 for High Sugar Accumulation in Citrus
- Activation of the Hippo pathway by the MIAT/miR-877-5p/UBN2 axis contributes to keloid formation
BibTeX
@misc{dushimyineza2026uncoupling,
title = {{Uncoupling of STING Accumulation and Activation upon Chromosome-Derived Extrachromosomal Circular DNA Formation}},
author = {H. Dushimyineza and J. Cai and M. T. Hayashi},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.23.761201},
url = {https://www.biorxiv.org/content/10.64898/2026.10.23.761201v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Uncoupling of STING Accumulation and Activation upon Chromosome-Derived Extrachromosomal Circular DNA Formation
AU - H. Dushimyineza
AU - J. Cai
AU - M. T. Hayashi
PY - 2026
DA - 2026/10/23
PB - bioRxiv
DO - 10.64898/2026.10.23.761201
UR - https://www.biorxiv.org/content/10.64898/2026.10.23.761201v1
AB - The innate immune system maintains cellular homeostasis by recognizing cytosolic nucleic acids. While the cGAS-STING pathway is well characterized in detecting non-self-DNA, its response to self-DNA originating from the host nucleus remains unclear. Extrachromosomal circular DNA (eccDNA), a form of self-DNA often enriched in cancer, has been implicated in immune modulation, yet its ability to activate cGAS-STING remains unresolved. Here, we developed a Cre-loxP-based eccDNA reporter system, where Cre-mediated eccDNA formation triggers expression of the fluorescent protein mCitrine, enabling time-resolved, single-cell analysis of chromosome-derived eccDNA dynamics and STING activation. Using an mRuby3-STING reporter, we found that low-dose plasmid transfection induced STING activation, as evidenced by modest STING accumulation and downstream cytokine induction. Cells carrying chromosome-derived cytosolic eccDNA also showed a modest, cGAS-dependent accumulation of STING. However, this accumulation was uncoupled from detectable STING-Ser366 phosphorylation or induction of downstream cytokines. These findings indicate that chromosome-derived eccDNA does not drive detectable STING signaling under the conditions tested, and that STING accumulation and its activation are mechanistically separable steps. This work provides a foundation for understanding the immunological roles of eccDNA in genome instability and cancer.
ER -