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

摘要 在美国，2型糖尿病(T2 DM)在美国人中的患病率特别高 印度(AI)社区。砷(As)，一种普遍存在的环境污染物，对人工智能的影响不成比例 社区，可以解释这种增加的风险。砷引起氧化应激和全身低度损伤 炎症导致靶组织中β细胞功能障碍和胰岛素抵抗。然而，AS对 由于这些发现缺乏连贯的机制，T2 DM一直存在争议。此前的研究主要集中在 关于表观基因组机制(例如，DNA甲基化、组蛋白修饰)，忽略了下游调控 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(M6A)，信使RNA上最普遍的表观转录修饰，它直接 参与了细胞应激反应。在实验系统中，砷诱导M6A反应。M6A还 调节T2 DM发病机制的关键过程，包括免疫反应和全身 发炎。M6A由一组称为读取器、写入器和擦除器(RWE)的蛋白质控制，负责 添加、解释和删除m6A标记。脂肪质量和肥胖相关蛋白(FTO)就是一个例子 一种砷敏感的m6A橡皮擦，与T2 DM和葡萄糖动态平衡有很强的联系。我们对老年人的初步研究 接触低水平砷的男性支持这些发现。我们建议检验改变了m6A的假设 在强心研究(SHS)中，RWE是AS相关T2 DM的可能机制。SHS是一种 亚利桑那州、俄克拉何马州和北达科他州/南达科他州人工智能社区正在进行的纵向研究，包括详细的临床 2型糖尿病和代谢综合征(METS)的数据。SHS已经测量了物种作为暴露数据，包括 儿童和成人的暴露窗口，在以前的研究中都与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m6A测序对mRNAm6A谱进行表位转录分析，并测量mRNAs的表达 在即将到来的SHS后续访问中，使用1100名参与者的全血进行20名RWE(计划于2022年- 23)。我们的具体目标是：1)确定过去和现在的AS暴露与表位翻译的关联 血液中m6A和RWEs基因表达水平的变化；2)确定血液中m6A的关联性 代谢标记物和蛋氨酸、临床T2 DM患病率和T2 DM控制的表位转录图谱 (糖化血红蛋白、蛋白尿)；3)开发一种预测性M6A指纹，量化T2 DM的风险 使用机器学习方法进行AS暴露。对于目标1和目标2，我们将进一步使用孟德尔 随机化以评估因果关系。高度人工智能成人群体的m6A谱特征 受T2 DM的影响，将揭示与糖尿病等普遍存在的毒物有关的生物学特征。此外 导致在美国和全球范围内减少AS暴露的干预措施，定义M6A和RWE在 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.