METTL3-Mediated STING Upregulation and Activation in Kupffer Cells Contribute to Radiation-Induced Liver Disease via Pyroptosis

Biao Wang; Yang Zhang; Hao Niu; Xiaomei Zhao; Genwen Chen; Qianqian Zhao; Guifen Ma; Shisuo Du; Zhaochong Zeng

doi:10.1016/j.ijrobp.2023.10.041

METTL3-Mediated STING Upregulation and Activation in Kupffer Cells Contribute to Radiation-Induced Liver Disease via Pyroptosis

Int J Radiat Oncol Biol Phys. 2024 May 1;119(1):219-233. doi: 10.1016/j.ijrobp.2023.10.041. Epub 2023 Oct 31.

Authors

Biao Wang¹, Yang Zhang¹, Hao Niu¹, Xiaomei Zhao¹, Genwen Chen¹, Qianqian Zhao¹, Guifen Ma¹, Shisuo Du², Zhaochong Zeng³

Affiliations

¹ Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai, China; Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China.
² Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai, China; Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China. Electronic address: du.shisuo@zs-hospital.sh.cn.
³ Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai, China; Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China. Electronic address: zeng.zhaochong@zs-hospital.sh.cn.

PMID: 37914138
DOI: 10.1016/j.ijrobp.2023.10.041

Abstract

Purpose: Radiation therapy is a vital adjuvant treatment for liver cancer, although the challenge of radiation-induced liver diseases (RILDs) limits its implementation. Kupffer cells (KCs) are a crucial cell population of the hepatic immune system, and their biologic function can be modulated by multiple epigenetic RNA modifications, including N⁶-methyladenosine (m⁶A) methylation. However, the mechanism for m⁶A methylation in KC-induced inflammatory responses in RILD remains unclear. The present study investigated the function of m⁶A modification in KCs contributing to RILD.

Methods and materials: Methylated RNA-immunoprecipitation sequencing and RNA transcriptome sequencing were used to explore the m⁶A methylation profile of primary KCs isolated from mice after irradiation with 3 × 8 Gy. Western blotting and quantitative real-time PCR were used to evaluate gene expression. DNA pulldown and chromatin immunoprecipitation assays were performed to verify target gene binding and identify binding sites.

Results: Methylated RNA-immunoprecipitation sequencing revealed significantly increased m⁶A modification levels in human KCs after irradiation, suggesting the potential role of upregulated m⁶A in RILD. In addition, the study results corroborated that methyltransferase-like 3 (METTL3) acts as a main modulator to promote the methylation and gene expression of TEAD1, leading to STING-NLRP3 signaling activation. Importantly, it was shown that IGF2BP2 functions as an m⁶A "reader" to recognize methylated TEAD1 mRNA and promote its stability. METTL3/TEAD1 knockdown abolished the activation of STING-NLRP3 signaling, protected against RILD, and suppressed inflammatory cytokines and hepatocyte apoptosis. Moreover, clinical human normal liver tissue samples collected after irradiation showed increased expression of STING and interleukin-1β in KCs compared with nonirradiated samples. Notably, STING pharmacologic inhibition alleviated irradiation-induced liver injury in mice, indicating its potential therapeutic role in RILD.

Conclusions: The results of our study reveal that TEAD1-STING-NLRP3 signaling activation contributes to RILD via METTL3-dependent m⁶A modification.

MeSH terms

Animals
Humans
Kupffer Cells* / metabolism
Liver Neoplasms* / metabolism
Methyltransferases / genetics
Mice
NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
Pyroptosis
RNA, Messenger / genetics
RNA-Binding Proteins / physiology
Up-Regulation

Substances

NLR Family, Pyrin Domain-Containing 3 Protein
RNA, Messenger
METTL3 protein, human
Methyltransferases
IGF2BP2 protein, human
RNA-Binding Proteins