Progressive polyadenylation and m6A modification of Ighg1 mRNA maintain IgG1 antibody homeostasis in antibody-secreting cells

Authors:

Yu Wang, Shaocun Zhang, Na Kang, Lihui Dong, Haochen Ni, Sichen Liu, Siankang Chong, Zhenglin Ji, Zhengpeng Wan, Xiangjun Chen, Fei Wang, Yun Lu, Baidong Hou, Pei Tong, Hai Qi, Meng Michelle Xu, Wanli Liu

Keywords:

antibody-secreting cells; YTHDF1; m6A; IgG antibody; lupus

Abstract:

Antigen-specific antibodies are generated by antibody-secreting cells (ASCs). How RNA post-transcriptional modification affects antibody homeostasis remains unclear. Here, we found that mRNA polyadenylations and N6-methyladenosine (m6A) modifications maintain IgG1 antibody production in ASCs. IgG heavy-chain transcripts (Ighg) possessed a long 3′ UTR with m6A sites, targeted by the m6A reader YTHDF1. B cell-specific deficiency of YTHDF1 impaired IgG production upon antigen immunization through reducing Ighg1 mRNA abundance in IgG1⁺ ASCs. Disrupting either the m6A modification of a nuclear-localized splicing intermediate Ighg1 or the nuclear localization of YTHDF1 reduced Ighg1 transcript stability. Single-cell RNA sequencing identified an ASC subset with excessive YTHDF1 expression in systemic lupus erythematosus patients, which was decreased upon therapy with immunosuppressive drugs. In a lupus mouse model, inhibiting YTHDF1-m6A interactions alleviated symptoms. Thus, we highlight a mechanism in ASCs to sustain the homeostasis of IgG antibody transcripts by integrating Ighg1 mRNA polyadenylation and m6A modification.

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