Epstein-Barr virus suppresses N6-methyladenosine modification of TLR9 to promote immune evasion

Xiaoyue Zhang; Zhengshuo Li; Qiu Peng; Can Liu; Yangge Wu; Yuqing Wen; Run Zheng; Chenxiao Xu; Junrui Tian; Xiang Zheng; Qun Yan; Jia Wang; Jian Ma

doi:10.1016/j.jbc.2024.107226

Epstein-Barr virus suppresses N⁶-methyladenosine modification of TLR9 to promote immune evasion

J Biol Chem. 2024 Mar 25;300(5):107226. doi: 10.1016/j.jbc.2024.107226. Online ahead of print.

Authors

Xiaoyue Zhang¹, Zhengshuo Li¹, Qiu Peng¹, Can Liu¹, Yangge Wu¹, Yuqing Wen¹, Run Zheng¹, Chenxiao Xu¹, Junrui Tian¹, Xiang Zheng², Qun Yan³, Jia Wang⁴, Jian Ma⁵

Affiliations

¹ Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China; NHC Key Laboratory of Carcinogenesis, Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Hunan Key Laboratory of Nonresolving Inﬂammation and Cancer, Hunan Key Laboratory of Cancer Metabolism, Changsha, Hunan, China.
² Department of Pathology, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China.
³ Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, China.
⁴ Department of Immunology, Changzhi Medical College, Changzhi, Shanxi, China. Electronic address: czmcwj@czmc.edu.cn.
⁵ Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China; Cancer Research Institute, School of Basic Medical Science, Central South University, Changsha, Hunan, China; NHC Key Laboratory of Carcinogenesis, Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Hunan Key Laboratory of Nonresolving Inﬂammation and Cancer, Hunan Key Laboratory of Cancer Metabolism, Changsha, Hunan, China. Electronic address: majian@csu.edu.cn.

Abstract

Epstein-Barr virus (EBV) is a human tumor virus associated with a variety of malignancies, including nasopharyngeal carcinoma, gastric cancers, and B-cell lymphomas. N⁶-methyladenosine (m⁶A) modifications modulate a wide range of cellular processes and participate in the regulation of virus-host cell interactions. Here, we discovered that EBV infection downregulates toll-like receptor 9 (TLR9) m⁶A modification levels and thus inhibits TLR9 expression. TLR9 has multiple m⁶A modification sites. Knockdown of METTL3, an m⁶A "writer", decreases TLR9 protein expression by inhibiting its mRNA stability. Mechanistically, Epstein-Barr nuclear antigen 1 increases METTL3 protein degradation via K48-linked ubiquitin-proteasome pathway. Additionally, YTHDF1 was identified as an m⁶A "reader" of TLR9, enhancing TLR9 expression by promoting mRNA translation in an m⁶A -dependent manner, which suggests that EBV inhibits TLR9 translation by "hijacking" host m⁶A modification mechanism. Using the METTL3 inhibitor STM2457 inhibits TLR9-induced B cell proliferation and immunoglobulin secretion, and opposes TLR9-induced immune responses to assist tumor cell immune escape. In clinical lymphoma samples, the expression of METTL3, YTHDF1, and TLR9 was highly correlated with immune cells infiltration. This study reveals a novel mechanism that EBV represses the important innate immunity molecule TLR9 through modulating the host m⁶A modification system.

Keywords: Epstein-Barr virus; METTL3; TLR9; immune evasion; m(6)A modification.