NR3C1/Glucocorticoid receptor activation promotes pancreatic ß-cell autophagy overload in response to glucolipotoxicity
NR3C1/Glucocorticoid receptor activation promotes pancreatic ß-cell autophagy overload in response to glucolipotoxicity
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DOI：
10.1080/15548627.2023.2200625
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发表时间：
2023-04-20
期刊：
影响因子：
13.3
通讯作者：
Han，Xiao
中科院分区：
文献类型：
--
作者：
Wu，Tijun;Shao，Yixue;Han，Xiao
糖尿病是一种以慢性高血糖为特征的复杂异质性疾病。其核心原因是胰腺β细胞衰竭导致的胰岛素分泌进行性受损，通常是在预先存在胰岛素抵抗的背景下。最近的研究表明，巨自噬/自噬对于维持β细胞的结构和功能是必不可少的，而过度的自噬也参与β细胞功能障碍和死亡。目前尚不清楚自噬在β细胞中是起保护作用还是有害作用，而我们在这里报道它依赖于NR 3C 1/糖皮质激素受体激活。我们证明，在糖脂毒性条件下，β细胞中的NR 3C 1激活后，才发生有害的过度活跃的自噬，最终促进糖尿病。转录组和N6-甲基腺苷（m6 A）甲基化组显示，NR 3C 1增强上调RNA去甲基化酶FTO β-细胞中的（脂肪量和肥胖相关）蛋白，这导致四个核心Atg基因mRNA上的m6 A修饰减少。（自噬相关）基因（Atg 12，Atg 5，Atg 16 l2，Atg 9a），因此，过度活跃的自噬和有缺陷的胰岛素输出;相反，通过特异性FTO抑制剂Dac 51实现的FTO抑制阻止了NR 3C 1引发的过度自噬活化。重要的是，Dac 51有效地减轻了高血糖β细胞特异性NR 3C 1过表达小鼠中受损的胰岛素分泌和葡萄糖耐受不良。我们的结果确定NR 3C 1-FTO-m6 A修饰-Atggenes轴作为胰腺β细胞中平衡自噬通量的关键介质，这为糖尿病的治疗提供了新的治疗靶点。β NR 3C 1小鼠：胰腺β细胞特异性NR 3C 1过表达小鼠; cFBS：炭剥离FBS; Ctrl：对照; ER：内质网; FTO：脂肪量和肥胖相关; GC：糖皮质激素; GRE：糖皮质激素反应元件; GSIS：葡萄糖刺激的胰岛素分泌测定; HFD：高脂饮食; HG：高葡萄糖; HsND：非糖尿病人; HsT 2D：2型糖尿病人; i. p.：腹腔注射; KSIS：钾刺激胰岛素分泌测定; m6 A：N6-甲基腺苷; MeRIP-seq：甲基化RNA免疫沉淀测序; NR 3C 1/GR：核受体亚家族3，C组，成员1; NR 3C 1-Enhc.：NR 3C 1增强; NC：阴性对照; Palm.：棕榈酸酯; RNA-seq：RNA测序; T2 D：2型糖尿病; TEM：透射电子显微镜; UTR：非翻译区; WT：野生型。
Diabetes is a complex and heterogeneous disorder characterized by chronic hyperglycemia. Its core cause is progressively impaired insulin secretion by pancreatic β-cell failures, usually upon a background of preexisting insulin resistance. Recent studies demonstrate that macroautophagy/autophagy is essential to maintain architecture and function of β-cells, whereas excessive autophagy is also involved in β-cell dysfunction and death. It has been poorly understood whether autophagy plays a protective or harmful role in β-cells, while we report here that it is dependent on NR3C1/glucocorticoid receptor activation. We proved that deleterious hyperactive autophagy happened only upon NR3C1 activation in β-cells under glucolipotoxic conditions, which eventually promoted diabetes. The transcriptome and theN6-methyladenosine (m6A) methylome revealed that NR3C1-enhancement upregulated the RNA demethylase FTO (fat mass and obesity associated) protein in β-cells, which caused diminished m6A modifications on mRNAs of four coreAtg(autophagy related) genes (Atg12, Atg5, Atg16l2, Atg9a) and, hence, hyperactive autophagy and defective insulin output; by contrast, FTO inhibition, achieved by the specific FTO inhibitor Dac51, prevented NR3C1-instigated excessive autophagy activation. Importantly, Dac51 effectively alleviated impaired insulin secretion and glucose intolerance in hyperglycemic β-cell specific NR3C1 overexpression mice. Our results determine that the NR3C1-FTO-m6A modifications-Atggenes axis acts as a key mediator of balanced autophagic flux in pancreatic β-cells, which offers a novel therapeutic target for the treatment of diabetes.Abbreviations:3-MA: 3-methyladenine; AAV: adeno-associated virus; Ac: acetylation; Ad: adenovirus; AL: autolysosome; ATG: autophagy related; AUC: area under curve; Baf A1: bafilomycin A1; βNR3C1 mice: pancreatic β-cell-specific NR3C1 overexpression mice; cFBS: charcoal-stripped FBS; Ctrl: control; ER: endoplasmic reticulum; FTO: fat mass and obesity associated; GC: glucocorticoid; GRE: glucocorticoid response element; GSIS: glucose-stimulated insulin secretion assay; HFD: high-fat diet; HG: high glucose; HsND: non-diabetic human; HsT2D: type 2 diabetic human; i.p.: intraperitoneal injected; KSIS: potassium-stimulated insulin secretion assay; m6A: N6-methyladenosine; MeRIP-seq: methylated RNA immunoprecipitation sequencing; NR3C1/GR: nuclear receptor subfamily 3, group C, member 1; NR3C1-Enhc.: NR3C1-enhancement; NC: negative control; Palm.: palmitate; RNA-seq: RNA sequencing; T2D: type 2 diabetes; TEM: transmission electron microscopy; UTR: untranslated region; WT: wild-type.