Role of adipose mRNA modifications in metabolic disease

脂肪 mRNA 修饰在代谢疾病中的作用

• 批准号: 10453266
• 负责人: LIANGYOU RUI
• 金额: $ 47.42万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10453266
• 关键词: Adipocytes; Adipose tissue; Adrenergic Agents; Binding; Brown Fat; Catalytic Domain; Cells; Complex; Development; Diabetes Mellitus; Embryo; Exercise; Fatty Liver; Fatty acid glycerol esters; Functional disorder; Gene Expression Profiling; Gene Proteins; Genetic; Genetic Transcription; Glycerol; Growth; High Fat Diet; Hormones; Impairment; Insulin; Insulin Resistance; Knockout Mice; Life; Life Cycle Stages; Link; Lipase; Lipolysis; Liver; Mediating; Messenger RNA; Metabolic; Metabolic Diseases; Metabolism; Methylation; Methyltransferase; Modeling; Modification; Monoacylglycerol Lipases; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nonesterified Fatty Acids; Nuclear Export; Obesity; Obesity associated disease; Outcome; Pathway interactions; Post-Translational Protein Processing; Process; Protein Biosynthesis; Protein Family; Proteins; RNA; RNA Binding; RNA Splicing; Reaction; Reader; Research; Resistance; Role; Signal Transduction; Starvation; Sympathetic Nervous System; System; Testing; Tissue Expansion; Tissues; Transcript; Translations; Triglycerides; adipokines; adiponectin; base; cell behavior; diet-induced obesity; driving force; epitranscriptomics; fatty liver disease; gain of function; glucose metabolism; improved; insulin signaling; mRNA Decay; mRNA Precursor; mutant; neonatal death; new therapeutic target; non-alcoholic fatty liver disease; novel; obesity treatment; obesogenic; overexpression; trafficking

Abstract Excessive white adipose tissue (WAT) is a hallmark of obesity and a causal factor for obesity-associated disease. Adipose secretion of adipokines is also dysregulated in obesity, further impairing WAT crosstalk with other tissues. Extensive research has been focused on gene transcriptions and protein posttranslational modifications and substantially advanced our understanding of WAT growth and functions. Importantly, mRNA connects the genetic control to translation of proteins responsible for cellular activities and functions. Like protein modifications, RNA is also extensively and reversibly modified in its life cycle. N6-methyladenosine (m6A) is the predominant RNA modification and catalyzed by a Mettl3/Mettl14 methyltransferase complex (m6A writer). YTHD family proteins (m6A readers) bind to m6A-methylated RNAs and regulate pre-mRNA splicing, nuclear export, decay, and/or translation of target transcripts. Global deletion of Mettl3, Mettl14, or Ythdc1 results in embryonic/neonatal death in mice, demonstrating the essential role of the m6A system in development and survival. However, m6A-based epitranscriptomic reprogramming has not been explored in WAT, and there is a gap in our understanding of RNA modifications and metabolism in obesity. In the preliminary study, we generated and characterized adipocyte-specific Mettl14 (Mettl14Δfat) and Ythdc1 (Ythdc1Δfat) knockout mice. Remarkably, both Mettl14Δfat and Ythdc1Δfat mice were resistant to diet-induced obesity, type 2 diabetes, and liver steatosis. Gene expression analysis suggested that Mettl14 and Ythdc1 target the lipolysis machinery, β adrenergic signaling (stimulating lipolysis), insulin signaling (suppressing lipolysis), and adipokine secretion. Consistently, WAT lipolysis was substantially elevated in Mettl14Δfat mice and Ythdc1Δfat mice, particularly under β adrenergic-stimulated conditions, contributing to WAT reduction. Adipose adiponectin expression was elevated in Mettl14Δfat and Ythdc1Δfat mice, contributing to improved insulin resistance, glucose metabolism, and liver steatosis. We hypothesize that Mettl14 induces m6A methylation selectively in mRNAs governing the lipolysis machinery, β adrenergic signaling, insulin signaling, and adipokine expression. Ythdc1 directly binds to and regulates the metabolism (pre-mRNA splicing, nuclear export, decay) of these m6A-modificed mRNAs, thereby guiding lipolysis, WAT growth, and adipokine- mediated adipose crosstalk with other tissues. We will test this hypothesis in 3 Aims. Aim 1 is to determine whether Mettl14 inhibits lipolysis and increases WAT expansion through RNA m6A methylation. Aim 2 is to determine whether Ythdc1 suppresses lipolysis and promotes WAT expansion by regulating metabolism of its bound RNAs. Aim 3 is to delineate whether Mettl14/Ythdc1 axis coordinates adipose crosstalk with other tissues via adipokines. The outcomes are expected to establish a new adipose Mettl14/m6A/Ythdc1-based epitranscriptomic reprogramming paradigm in obesity and metabolic disease.

抽象的 过多的白色脂肪组织（WAT）是肥胖的标志，是肥胖相关的因果因素 疾病。脂肪因子的脂肪分泌在肥胖症中也失调，进一步损害了与 其他组织。广泛的研究集中在基因转录和翻译后蛋白质上 修改并大大提高了我们对WAT生长和功能的理解。重要的是，mRNA 将遗传控制与负责细胞活性和功能的蛋白质的翻译联系起来。喜欢 蛋白质修饰，RNA在其生命周期中也经过广泛和可逆的修饰。 N6-甲基腺苷 （M6A）是主要的RNA修饰，并由Mettl3/Mettl14甲基转移酶复合酶催化 （M6A作家）。 YTHD家族蛋白（M6A读取器）与M6A-甲基化的RNA结合并调节前MRNA 目标转录本的剪接，核出口，衰减和/或翻译。 METTL3，METTL14或 YTHDC1导致小鼠的胚胎/新生儿死亡，证明了M6A系统在 发展和生存。但是，尚未在 WAT，我们对肥胖症中RNA修饰和代谢的理解存在差距。在 初步研究，我们生成并表征了脂肪细胞特异性的mettl14（mettl14ΔFat）和ythdc1 （YTHDC1ΔFAT）敲除小鼠。值得注意的是，Mettl14ΔFAT和YTHDC1ΔFAT小鼠对饮食诱导的抗性 肥胖，2型糖尿病和肝脏脂肪变性。基因表达分析表明mettl14和ythdc1 靶向脂解机制，β肾上腺肾上腺素信号（刺激脂解），胰岛素信号（抑制 脂解）和脂肪因子分泌。一致地，在Mettl14ΔFat小鼠中显着升高WAT脂解 和YTHDC1ΔFAT小鼠，特别是在β肾上腺素刺激的条件下，导致还原。 在Mettl14ΔFAT和YTHDC1ΔFAT小鼠中，脂肪脂肪蛋白表达升高，有助于改善 胰岛素抵抗，葡萄糖代谢和肝脂肪变性。我们假设METTL14诱导M6A 甲基化在控制脂解机，β肾上腺肾上腺素信号，胰岛素信号传导的mRNA中，甲基化 和脂肪因子表达。 YTHDC1直接结合并调节新陈代谢（前MRNA剪接，核 这些M6A修饰的mRNA的出口，衰减，从而指导脂解，WAT生长和脂肪因子 - 介导的脂肪串扰与其他组织。我们将在3个目标中检验这一假设。目标1是确定 通过RNA M6A甲基化膨胀。目标2是 确定YTHDC1是否通过调节其代谢来抑制脂解和促进WAT膨胀 绑定的RNA。 AIM 3是描述Mettl14/Ythdc1轴是否与其他 通过脂肪因子组织。结果有望建立新的脂肪METTL14/M6A/YTHDC1 肥胖和代谢疾病中的同意重编程范式。