突破 Alu 双重 RNA 的自我耐受性 导致 MDA5 介导的炎症
Sadeem Ahmad1, Xin Mu1, Fei Yang1
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA.
Cell
|February 4, 2018
概括
MDA5受体的异常激活会导致像艾卡迪-古提耶氏综合征 (AGS) 这样的免疫疾病,这是由于Alu反元素的细胞dSRNA. 这些自我dsRNAs被MDA5的AGS变体识别,导致免疫系统的失调.
科学领域:
- 免疫学
- 分子生物学
- 遗传学
背景情况:
- 异常激活先天免疫受体,如MDA5,与艾卡迪-古提耶氏综合征 (AGS) 等免疫疾病有关.
- MDA5是病毒双链RNA (dsRNA) 的传感器,对于启动抗病毒免疫反应至关重要.
- 对细胞dRNA的自我耐受性丧失可能会引发不适当的免疫激活.
研究的目的:
- 研究艾卡迪-古提耶氏综合征中构成MDA5激活的机制.
- 确定 Alu 逆元素及其衍生 dsRNA 在 MDA5 激活中的作用.
- 探索细胞环境对MDA5自我/非自我歧视的影响.
主要方法:
- 开发和应用一种新的RNase保护/RNA测序方法 (RNA-seq).
- 对不同dRNA结构,包括细胞Alu-dsRNA的MDA5线索形成的分析.
- 研究细胞RNA度对MDA5寡合化的影响.
主要成果:
- 在AGS中构成MDA5的激活是由来自Alu反元素的细胞dSRNA的耐受性损失引起的.
- 在AGS中发现的MDA5变异体对dsRNA结构不规则的敏感性降低,从而使丝组装在Alu-dsRNA上.
- 发现富含RNA的细胞环境抑制了异常的MDA5寡合化,这表明了环境依赖的免疫感应.
结论:
- 在识别dRNA时MDA5的效率增加以牺牲自我识别为代价,导致自身免疫性疾病.
- Alu-dsRNAs作为内源性,类似病毒的元素, 塑造了灵长类的免疫系统.
- 了解细胞dSRNA和反元素对MDA5的调节,可以深入了解免疫平衡和疾病的发生.
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