Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Genomics and Proteomics Core Laboratory, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Brain Behav. 2023 Mar;13(3):e2897. doi: 10.1002/brb3.2897. Epub 2023 Feb 7.
Autoimmune encephalitis (AE) is caused by autoantibodies attacking neuronal cell surface antigens and/or synaptic antigens. We previously demonstrated that S100A6 was hypomethylated in patients with AE and that it promoted B lymphocyte infiltration through the simulated blood-brain barrier (BBB). In this study, we focused on the epigenetic regulation of S100A6, the process by which S100A6 affects B lymphocyte infiltration, and the therapeutic potential of S100A6 antibodies.
We enrolled and collected serum from 10 patients with AE and 10 healthy control (HC) subjects. Promoter methylation and 5-azacytidine treatment assays were conducted to observe the methylation process of S100A6. The effect of S100A6 on B lymphocytes was analyzed using an adhesion assay and leukocyte transendothelial migration (LTEM) assay. A LTEM assay was also used to compare the effects of the serum of HCs, serum of AE patients, S100A6 recombinant protein, and S100A6 antibodies on B lymphocytes.
The promoter methylation and 5-azacytidine treatment assays confirmed that S100A6 was regulated by DNA methylation. The adhesion study demonstrated that the addition of S100A6 enhanced adhesion between B lymphocytes and a BBB endothelial cell line in a concentration-dependent manner. The LTEM assay showed that the serum of AE patients, as well as S100A6, promoted B lymphocyte infiltration and that this effect could be attenuated by S100A6 antibodies.
We clarified that S100A6 was under epigenetic regulation in patients with AE and that it helped B lymphocytes to adhere to and infiltrate the BBB endothelial layer, which could be counteracted by S100A6 antibodies. Therefore, the methylation profile of S100A6 could be a marker of the activity of AE, and countering the effect of S100A6 may be a potential treatment target for AE.
自身免疫性脑炎（AE）是由自身抗体攻击神经元细胞表面抗原和/或突触抗原引起的。我们之前证明，AE 患者的 S100A6 呈低甲基化状态，并且它通过模拟血脑屏障（BBB）促进 B 淋巴细胞浸润。在这项研究中，我们专注于 S100A6 的表观遗传调控、S100A6 影响 B 淋巴细胞浸润的过程以及 S100A6 抗体的治疗潜力。
我们招募并收集了 10 名 AE 患者和 10 名健康对照（HC）受试者的血清。进行启动子甲基化和 5-氮杂胞苷处理实验，以观察 S100A6 的甲基化过程。使用黏附实验和白细胞跨内皮迁移（LTEM）实验分析 S100A6 对 B 淋巴细胞的影响。LTEM 实验还用于比较 HC 血清、AE 患者血清、S100A6 重组蛋白和 S100A6 抗体对 B 淋巴细胞的影响。
启动子甲基化和 5-氮杂胞苷处理实验证实 S100A6 受 DNA 甲基化调控。黏附实验表明，S100A6 的添加以浓度依赖的方式增强了 B 淋巴细胞与 BBB 内皮细胞系之间的黏附。LTEM 实验表明，AE 患者的血清以及 S100A6 促进了 B 淋巴细胞的浸润，而 S100A6 抗体可以减弱这种作用。
我们阐明了 AE 患者的 S100A6 受到表观遗传调控，它有助于 B 淋巴细胞黏附和浸润 BBB 内皮层，而 S100A6 抗体可以拮抗其作用。因此，S100A6 的甲基化谱可能是 AE 活动的标志物，拮抗 S100A6 的作用可能是 AE 的潜在治疗靶点。
