Background and aims

Mouse models of colitis have been used to study the pathogenesis of inflammatory bowel disease (IBD) and for pre-clinical development of therapeutic agents. Various epigenetic pathways have been shown to play important regulatory roles in IBD. Reversible N⁶-methyladenosine (m⁶A) methylation represents a new layer of post-transcriptional gene regulation that affects a variety of biological processes. We aim to study how deletion of a critical component of m⁶A writer complex, METTL14, in T cells affects the development of colitis.

Methods

Conditional Mettl14 was lineage specifically deleted with CD4-regulated Cre in T cells. Colitis phenotype was determined by H&E staining, colon weight-to-length ratio and cytokine expression. We additionally utilized T cell transfer model of colitis and adoptive transfer of regulatory T cells. Mice were treated with antibiotics to determine if the colitis could be attenuated.

Results

METTL14 deficiency in T cells induced spontaneous colitis in mice. This was characterized by increased inflammatory cell infiltration, increased colonic weight-to-length ratio and increased Th1 and Th17 cytokines. The colitis development was due to dysfunctional regulatory T (T_reg) cells, as adoptive transfer of WT T_reg cells attenuated the colitis phenotype. The METTL14-deficient T_reg cells have decreased RORγt expression compared with WT controls. METTL14 deficiency caused impaired induction of naïve T cells into induced T_reg cells. Antibiotic treatment notably attenuated the colitis development.

Conclusion

Here we report a new mouse model of spontaneous colitis based on perturbation of RNA methylation in T cells. The colitis is T cell-mediated and dependent on the microbiome. This model represents a new tool for elucidating pathogenic pathways, studying the contribution of intestinal microbiome and preclinical testing of therapeutic agents for inflammatory bowel disease.

中文翻译：

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通过缺失 T 细胞中的 RNA m6A 甲基转移酶成分 METTL14 诱导小鼠自发性结肠炎的新模型。

背景和目标

结肠炎小鼠模型已被用于研究炎症性肠病 (IBD) 的发病机制和治疗药物的临床前开发。各种表观遗传途径已被证明在 IBD 中发挥重要的调节作用。可逆的N ⁶ -甲基腺苷 (m ⁶ A) 甲基化代表了影响各种生物过程的转录后基因调控的新层。我们的目标是研究T 细胞中 m ⁶ A writer 复合体 METTL14的关键成分的缺失如何影响结肠炎的发展。

方法

条件性Mettl14在 T 细胞中被 CD4 调节的 Cre 特异性删除。结肠炎表型通过 H&E 染色、结肠重量与长度比和细胞因子表达确定。我们还利用了结肠炎的 T 细胞转移模型和调节性 T 细胞的过继转移。小鼠接受抗生素治疗以确定结肠炎是否可以减轻。

结果

T 细胞中的 METTL14 缺陷诱导小鼠自发性结肠炎。其特征是炎症细胞浸润增加、结肠重量与长度比增加以及 Th1 和 Th17 细胞因子增加。结肠炎的发展是由于功能失调的调节性 T (T _reg ) 细胞，因为 WT T _reg细胞的过继转移减弱了结肠炎表型。与 WT 对照相比，METTL14 缺陷型 T _reg细胞的 RORγt 表达降低。METTL14 缺陷导致幼稚 T 细胞向诱导性 T _reg细胞的诱导受损。抗生素治疗显着减弱了结肠炎的发展。

结论

在这里，我们报告了一种基于 T 细胞中 RNA 甲基化扰动的自发性结肠炎新小鼠模型。结肠炎是 T 细胞介导的，依赖于微生物组。该模型代表了一种阐明致病途径、研究肠道微生物组的贡献和炎症性肠病治疗药物的临床前测试的新工具。