缺乏Gdap1的诱导多能干细胞衍生运动神经元的快速退化引发了线粒体维持的先天免疫反应。

Rapid degeneration of iPSC-derived motor neurons lacking Gdap1 engages a mitochondrial-sustained innate immune response.

作者信息

León Marian, Prieto Javier, Molina-Navarro María Micaela, García-García Francisco, Barneo-Muñoz Manuela, Ponsoda Xavier, Sáez Rosana, Palau Francesc, Dopazo Joaquín, Izpisua Belmonte Juan Carlos, Torres Josema

机构信息

Departamento Biología Celular, Biología Funcional y Antropología Física, Universitat de València, Burjassot, 46100, València, Spain.

Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.

出版信息

Cell Death Discov. 2023 Jul 1;9(1):217. doi: 10.1038/s41420-023-01531-w.

Abstract

Charcot-Marie-Tooth disease is a chronic hereditary motor and sensory polyneuropathy targeting Schwann cells and/or motor neurons. Its multifactorial and polygenic origin portrays a complex clinical phenotype of the disease with a wide range of genetic inheritance patterns. The disease-associated gene GDAP1 encodes for a mitochondrial outer membrane protein. Mouse and insect models with mutations in Gdap1 have reproduced several traits of the human disease. However, the precise function in the cell types affected by the disease remains unknown. Here, we use induced-pluripotent stem cells derived from a Gdap1 knockout mouse model to better understand the molecular and cellular phenotypes of the disease caused by the loss-of-function of this gene. Gdap1-null motor neurons display a fragile cell phenotype prone to early degeneration showing (1) altered mitochondrial morphology, with an increase in the fragmentation of these organelles, (2) activation of autophagy and mitophagy, (3) abnormal metabolism, characterized by a downregulation of Hexokinase 2 and ATP5b proteins, (4) increased reactive oxygen species and elevated mitochondrial membrane potential, and (5) increased innate immune response and p38 MAP kinase activation. Our data reveals the existence of an underlying Redox-inflammatory axis fueled by altered mitochondrial metabolism in the absence of Gdap1. As this biochemical axis encompasses a wide variety of druggable targets, our results may have implications for developing therapies using combinatorial pharmacological approaches and improving therefore human welfare. A Redox-immune axis underlying motor neuron degeneration caused by the absence of Gdap1. Our results show that Gdap1 motor neurons have a fragile cellular phenotype that is prone to degeneration. Gdap1 iPSCs differentiated into motor neurons showed an altered metabolic state: decreased glycolysis and increased OXPHOS. These alterations may lead to hyperpolarization of mitochondria and increased ROS levels. Excessive amounts of ROS might be the cause of increased mitophagy, p38 activation and inflammation as a cellular response to oxidative stress. The p38 MAPK pathway and the immune response may, in turn, have feedback mechanisms, leading to the induction of apoptosis and senescence, respectively. CAC, citric acid cycle; ETC, electronic transport chain; Glc, glucose; Lac, lactate; Pyr, pyruvate.

摘要

夏科-马里-图思病是一种慢性遗传性运动和感觉性多神经病,主要累及施万细胞和/或运动神经元。其多因素和多基因起源描绘了该疾病复杂的临床表型以及广泛的遗传模式。与该疾病相关的基因GDAP1编码一种线粒体外膜蛋白。Gdap1发生突变的小鼠和昆虫模型再现了人类疾病的一些特征。然而,该基因在受疾病影响的细胞类型中的具体功能仍不清楚。在这里,我们使用来自Gdap1基因敲除小鼠模型的诱导多能干细胞,以更好地了解该基因功能丧失所导致疾病的分子和细胞表型。Gdap1基因缺失的运动神经元表现出一种脆弱的细胞表型,易于早期退化,表现为:(1)线粒体形态改变,这些细胞器的碎片化增加;(2)自噬和线粒体自噬激活;(3)代谢异常,表现为己糖激酶2和ATP5b蛋白下调;(4)活性氧增加和线粒体膜电位升高;(5)固有免疫反应增加和p38丝裂原活化蛋白激酶激活。我们的数据揭示了在缺乏Gdap1的情况下,由线粒体代谢改变所驱动的潜在氧化还原-炎症轴的存在。由于这个生化轴包含多种可成药靶点,我们的结果可能对采用联合药理学方法开发治疗方法具有启示意义,从而改善人类健康。缺乏Gdap1导致运动神经元退化的氧化还原-免疫轴。我们的结果表明,Gdap1基因缺失的运动神经元具有易于退化的脆弱细胞表型。分化为运动神经元的Gdap1诱导多能干细胞表现出代谢状态改变:糖酵解减少,氧化磷酸化增加。这些改变可能导致线粒体超极化和活性氧水平升高。过量的活性氧可能是线粒体自噬增加、p38激活和炎症作为细胞对氧化应激反应增加的原因。p38丝裂原活化蛋白激酶途径和免疫反应反过来可能具有反馈机制,分别导致细胞凋亡和衰老的诱导。CAC,柠檬酸循环;ETC,电子传递链;Glc,葡萄糖;Lac,乳酸;Pyr,丙酮酸。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/3d0f/10314916/a4ffe9d6a7dc/41420_2023_1531_Figa_HTML.jpg

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