The Epitranscriptome as a Novel Mechanism of Arsenic-Induced Diabetes.

总结 在美国，2型糖尿病（T2 DM）的患病率在美国人中特别高， 印第安人社区。砷（As）是一种普遍存在的环境污染物，对AI的影响不成比例 社区，可以解释这种增加的风险。砷诱导氧化应激和全身性低水平 炎症导致靶组织中的β细胞功能障碍和胰岛素抵抗。然而，As对 由于这些发现缺乏一致的机制，T2 DM一直存在争议。以前的研究都集中 关于表观基因组机制（例如，DNA甲基化，组蛋白修饰），忽略下游调控 可以更直接地塑造表型的机制。我们建议研究RNA修饰N6- 甲基腺苷（m6 A），信使RNA上最普遍的表观修饰，其直接 参与细胞应激反应。在实验系统中，砷诱导m6 A反应。m6a 调节T2 DM发病机制的关键过程，包括免疫反应和全身性 炎症m6 A由一组称为阅读器、写入器和擦除器（RWE）的蛋白质控制， 添加、解释和删除m6 A标记。脂肪量和肥胖相关蛋白（FTO）就是一个例子 砷敏感的m6 A橡皮擦与T2 DM和葡萄糖稳态密切相关。我们在老年人中的试点研究 暴露于低水平砷的男性支持这些发现。我们建议测试改变m6 A的假设， 和RWE是强心研究（SHS）中AS相关T2 DM的合理机制。SHS是一种 正在亚利桑那州、俄克拉荷马州和北/南达科他州的AI社区进行的纵向研究， T2 DM和代谢综合征（MetS）的数据。SHS测量了物种As暴露数据，包括 儿童期和成人期暴露窗，在先前的研究中均与T2 DM独立相关。 利用队列设计、暴露和表型数据、基础设施和研究团队，我们建议 通过m6 A测序进行mRNA m6 A谱的表位转录组学分析并测量mRNA表达 在即将到来的SHS随访访视（计划于2022年- 23）。我们的具体目标是：1）确定过去和现在的As暴露与epitranscriptomic 血液中m6 A和RWEs mRNA表达水平的概况; 2）确定血液中m6 A和RWEs mRNA表达水平的相关性。 代谢标志物和MetS、临床T2 DM患病率和T2 DM控制的表观转录谱 （糖化血红蛋白，白蛋白尿）; 3）开发预测性m6 A指纹，量化T2 DM的风险， to As暴露using运用machine机器learning学习approaches方法.对于目标1和2，我们将进一步使用孟德尔 随机化以评估因果关系。在AI成人群体中的m6 A谱的表征高度 T2 DM的影响将揭示将普遍的毒物如As与糖尿病联系起来的生物学特征。此外 导致干预措施，以减少美国和全球的As暴露，定义m6 A和RWE在以下方面的作用： T2 DM可能为未来的糖尿病治疗提供新的靶点。

SUMMARY In the United States, the prevalence of type 2 diabetes mellitus (T2DM) is particularly high among American Indian (AI) communities. Arsenic (As), a pervasive environmental contaminant disproportionately affecting AI communities, may explain this increased risk. Arsenic induces oxidative stress and systemic low-grade inflammation leading to β-cell dysfunction and insulin resistance in target tissues. However, the impact of As on T2DM has been disputed due to a lack of coherent mechanism for these findings. Previous studies have focused on epigenomic mechanisms (e.g., DNA methylation, histone modifications), overlooking downstream regulatory mechanisms that can more directly shape phenotypes. We propose to investigate the RNA modification N6- methyladenosine (m6A), the most prevalent epitranscriptomic modification on messenger RNA, which is directly involved in the cellular stress response. In experimental systems, arsenic induces a m6A response. m6A also modulates key processes underlying T2DM pathogenesis, including immune response and systemic inflammation. m6A is controlled by a group of proteins called reader, writer, and erasers (RWEs), responsible for adding, interpreting, and removing m6A marks. Fat mass and obesity-associated protein (FTO) is one example of an arsenic-sensitive m6A eraser with strong ties to T2DM and glucose homeostasis. Our pilot study in elderly men exposed to low-level arsenic supported these findings. We propose to test the hypothesis that altered m6A and RWEs are plausible mechanisms for As-related T2DM in the Strong Heart Study (SHS). The SHS is an ongoing longitudinal study in AI communities in Arizona, Oklahoma, and North/South Dakota with detailed clinical data for T2DM and metabolic syndrome (MetS). The SHS has measured speciated As exposure data covering childhood and adult exposure windows, both independently associated with T2DM in previous research. Leveraging the cohort design, exposure and phenotypic data, infrastructure, and study team, we propose to conduct epitranscriptomic analysis of mRNA m6A profiles via m6A sequencing and measure mRNA expression of 20 RWEs using whole blood from 1100 participants at the upcoming SHS follow up visit (scheduled for 2022- 23). Our specific aims are to: 1) determine the association of past and current As exposure with epitranscriptomic profiles of m6A and RWEs mRNA expression levels in blood; 2) determine the association of blood m6A epitranscriptomic profiles with metabolic markers and MetS, clinical T2DM prevalence, and T2DM control (glycated hemoglobin, albuminuria); 3) develop a predictive m6A fingerprint that quantifies the risk of T2DM due to As exposure using machine learning approaches. For aims 1 and 2 we will further use Mendelian randomization to assess causal relationships. Characterization of m6A profiles in a population of AI adults highly impacted by T2DM will reveal biological features linking a pervasive toxicant such as As to diabetes. In addition to leading to interventions to reduce As exposure in the US and globally, defining the roles of m6A and RWEs in T2DM may contribute to new targets for future diabetes therapies.