Yang Yiying, Zhang Ying, Xie Shasha, Liu Ke, Liu Meidong, Li Yisha, Luo Hui, Zuo Xiaoxia, Zhang Huali, Guo Muyao
Department of Rheumatology, Xiangya Hospital, Department of Pathophysiology, Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.
Sepsis Translational Medicine Key Lab of Hunan Province, Changsha, Hunan, China.
Mol Med. 2025 Jun 12;31(1):236. doi: 10.1186/s10020-025-01295-2.
METTL3, an m6A methyltransferase, enhances germinal center responses. This study explores its role in lupus B cells and its impact on B-cell activation.
METTL3 and m6A levels in B cells from systemic lupus erythematosus (SLE) patients and lupus-prone mice were analyzed using m6A dot blot, RT-qPCR, western blotting, and flow cytometry. B-cell activation and differentiation were induced with lipopolysaccharide (LPS). The effects of METTL3 overexpression or inhibition on B-cell maturation were assessed . In Raji B cells, METTL3 and PAX5 knockdowns were performed to examine their regulatory relationship. EMSA and dual-luciferase assays confirmed PAX5 binding to the METTL3 promoter, while RIP and actinomycin D assays evaluated METTL3’s interaction with PAX5 mRNA. MeRIP-seq profiled m6A modifications across B-cell subsets.
METTL3 expression and m6A levels were significantly elevated in B cells from SLE patients, with METTL3 levels positively correlating with disease activity. Elevated m6A and METTL3 levels were observed in both naïve and activated B cells but decreased markedly during differentiation into ASCs, both and . MeRIP-seq analysis identified distinct m6A methylation patterns among B-cell subsets, particularly in key transcription factors critical for B-cell activation and differentiation. METTL3 facilitated pre-B cell development in bone marrow and maintained the balance of splenic B-cell subsets in mice. Furthermore, METTL3 preserved B-cell identity and enhanced activation. Mechanistically, METTL3 bound to mRNA, stabilizing it via m6A modification and promoting PAX5 expression. In turn, PAX5 directly bound to the promoter, driving its expression.
The elevated expression of METTL3 in lupus B cells is linked to the maintenance of autoreactive B-cell hyperresponsiveness, contributing to the pathogenesis of SLE. The reciprocal regulation between METTL3 and PAX5 highlights a critical mechanism underlying B-cell activation and persistence in autoimmune conditions like lupus.
The online version contains supplementary material available at 10.1186/s10020-025-01295-2.
m6A甲基转移酶METTL3可增强生发中心反应。本研究探讨其在狼疮B细胞中的作用及其对B细胞活化的影响。
使用m6A斑点印迹、RT-qPCR、蛋白质印迹和流式细胞术分析系统性红斑狼疮（SLE）患者和狼疮易感小鼠B细胞中METTL3和m6A水平。用脂多糖（LPS）诱导B细胞活化和分化。评估METTL3过表达或抑制对B细胞成熟的影响。在Raji B细胞中，进行METTL3和PAX5敲低以检查它们的调控关系。电泳迁移率变动分析（EMSA）和双荧光素酶测定证实PAX5与METTL3启动子结合，而RNA免疫沉淀（RIP）和放线菌素D测定评估METTL3与PAX5 mRNA的相互作用。MeRIP-seq分析了B细胞亚群中的m6A修饰情况。
SLE患者B细胞中METTL3表达和m6A水平显著升高，METTL3水平与疾病活动度呈正相关。在幼稚和活化B细胞中均观察到m6A和METTL3水平升高，但在分化为浆细胞样效应细胞（ASCs）的过程中均显著降低。MeRIP-seq分析确定了B细胞亚群之间不同的m6A甲基化模式，特别是在对B细胞活化和分化至关重要的关键转录因子中。METTL3促进小鼠骨髓中前B细胞的发育，并维持脾脏B细胞亚群的平衡。此外，METTL3维持B细胞特性并增强其活化。机制上，METTL3与PAX5 mRNA结合，通过m6A修饰使其稳定并促进PAX5表达。反过来，PAX5直接与METTL3启动子结合，驱动其表达。
狼疮B细胞中METTL3表达升高与自身反应性B细胞高反应性的维持有关，促进了SLE的发病机制。METTL3和PAX5之间的相互调节突出了狼疮等自身免疫性疾病中B细胞活化和持续存在的关键机制。
在线版本包含可在10.1186/s10020-025-01295-2获取的补充材料。
