De Jesus Dario F, Zhang Zijie, Brown Natalie K, Li Xiaolu, Gaffrey Matthew J, Kahraman Sevim, Wei Jiangbo, Hu Jiang, Basile Giorgio, Xiao Ling, Rana Tariq M, Mathews Clayton, Powers Alvin C, Atkinson Mark A, Eizirik Decio L, Dhe-Paganon Sirano, Parent Audrey V, Qian Wei-Jun, He Chuan, Kulkarni Rohit N
bioRxiv. 2023 Feb 16:2023.02.16.528701. doi: 10.1101/2023.02.16.528701.
Type 1 Diabetes (T1D) is characterized by autoimmune-mediated destruction of insulin-producing β-cells. Several observations have renewed interest in the innate immune system as an initiator of the disease process against β-cells. Here, we show that N -Methyladenosine (m A) is an adaptive β-cell safeguard mechanism that accelerates mRNA decay of the 2'-5'-oligoadenylate synthetase (OAS) genes to control the antiviral innate immune response at T1D onset. m A writer methyltransferase 3 (METTL3) levels increase drastically in human and mouse β-cells at T1D onset but rapidly decline with disease progression. Treatment of human islets and EndoC-βH1 cells with pro-inflammatory cytokines interleukin-1 β and interferon α mimicked the METTL3 upregulation seen at T1D onset. Furthermore, m A-sequencing revealed the m A hypermethylation of several key innate immune mediators including and in human islets and EndoC-βH1 cells challenged with cytokines. METTL3 silencing in human pseudoislets or EndoC-βH1 cells enhanced OAS levels by increasing its mRNA stability upon cytokine challenge. Consistently, gene therapy, to prolong Mettl3 overexpression specifically in β-cells, delayed diabetes progression in the non-obese diabetic (NOD) mouse model of T1D by limiting the upregulation of pointing to potential therapeutic relevance. Mechanistically, the accumulation of reactive oxygen species blocked METTL3 upregulation in response to cytokines, while physiological levels of nitric oxide promoted its expression in human islets. Furthermore, for the first time to our knowledge, we show that the cysteines in position C276 and C326 in the zinc finger domain of the METTL3 protein are sensitive to S-nitrosylation (SNO) and are significant for the METTL3 mediated regulation of OAS mRNA stability in human β-cells in response to cytokines. Collectively, we report that m A regulates human and mouse β-cells to control the innate immune response during the onset of T1D and propose targeting METTL3 to prevent β-cell death in T1D.
1型糖尿病（T1D）的特征是自身免疫介导的胰岛素生成β细胞破坏。一些观察结果重新引发了人们对固有免疫系统作为针对β细胞疾病进程启动者的兴趣。在此，我们表明N - 甲基腺苷（m⁶A）是一种适应性β细胞保护机制，可加速2'-5'-寡腺苷酸合成酶（OAS）基因的mRNA衰变，以在T1D发病时控制抗病毒固有免疫反应。在T1D发病时，人类和小鼠β细胞中的m⁶A写入器甲基转移酶3（METTL3）水平急剧增加，但随着疾病进展迅速下降。用促炎细胞因子白细胞介素-1β和干扰素α处理人类胰岛和EndoC-βH1细胞，模拟了T1D发病时所见的METTL3上调。此外，m⁶A测序揭示了在受到细胞因子攻击的人类胰岛和EndoC-βH1细胞中，包括[具体基因名称未给出]和[具体基因名称未给出]在内的几种关键固有免疫介质的m⁶A超甲基化。在人类假胰岛或EndoC-βH1细胞中敲低METTL3，通过在细胞因子攻击时增加其mRNA稳定性来提高OAS水平。一致地，通过基因治疗，特别是在β细胞中延长Mettl3的过表达，通过限制[具体基因名称未给出]的上调，延缓了T1D非肥胖糖尿病（NOD）小鼠模型中的糖尿病进展，表明其具有潜在的治疗相关性。从机制上讲，活性氧的积累阻断了METTL3对细胞因子的上调反应，而生理水平的一氧化氮促进了其在人类胰岛中的表达。此外，据我们所知，我们首次表明METTL3蛋白锌指结构域中C276和C326位置的半胱氨酸对S-亚硝基化（SNO）敏感，并且对于METTL3介导的人类β细胞中OAS mRNA稳定性在细胞因子反应中的调节具有重要意义。总体而言，我们报告m⁶A调节人类和小鼠β细胞以控制T1D发病期间的固有免疫反应，并提出靶向METTL3以预防T1D中的β细胞死亡。
