Unexpected opposing biological effect of genetic risk factors for Parkinson's disease
Unexpected opposing biological effect of genetic risk factors for Parkinson's disease
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帕金森病遗传危险因素的意外相反生物学效应
DOI：
10.1101/702340
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Keatinge M
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文献类型：
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作者：
Keatinge M
双等位基因葡萄糖脑苷脂酶（GBA）突变导致溶酶体贮积症戈谢病（GD），而异源GBA变异体是帕金森病（PD）最强和最常见的遗传危险因素。在PD中也报告了其他溶酶体贮积症基因变体的过度负担，特别是SMPD 1（编码酸性鞘磷脂酶（ASM））。然而，GBA和SMPD 1是否在遗传上相互作用尚不清楚。斑马鱼是测试这种相互作用的理想脊椎动物系统。我们先前描述了agba 1 −/−突变斑马鱼系，其显示了人类GD的关键标志。在这项工作中，我们描述了联合葡萄糖脑苷脂酶（GCase）和ASM缺乏ingba 1 −/−; smpd 1 −/−双突变斑马鱼的生物学相互作用。我们观察到，与gba 1 −/−或smpd 1 −/−相比，斑马鱼的葡萄糖神经酰胺、神经酰胺和其他关键鞘脂或其代谢物ingba 1 −/−; smpd 1 −/−显著增加。出乎意料的是，我们观察到ASM失活对行为和疾病持续时间的显著改善作用，导致特征性运动表型的拯救和存活率的提高。我们确定了线粒体呼吸链功能的完全拯救和脂质过氧化的正常化是观察到的拯救效应ingba 1 −/−; smpd 1 −/−的潜在机制。在人神经母细胞瘤SH-SY 5 Y细胞中，ASM敲除和GCase抑制的组合意外地导致单体α-突触核蛋白（PD中的关键致病蛋白）的减少，这与大自噬通量的变化无关。我们的工作突出了调查基因-基因相互作用的下游功能后果的重要性，在复杂的相互作用途径，以确定任何复合risk.Significance statementThe遗传风险变异对疾病发病率的累加效应是一个流行的，但往往未经证实的假设。溶酶体疾病基因葡萄糖脑苷脂酶1（GBA 1）和鞘磷脂酶1（SMPD 1）的变异是帕金森病（PD）的危险因素。斑马鱼非常适合研究基因间的相互作用。我们研究了engba 1 −/−和smpd 1 −/− ingba 1 −/−; smpd 1 −/−双突变斑马鱼之间的遗传相互作用，并观察到鞘磷脂酶缺乏对gba 1 −/−相关表型的意外改善作用，由于线粒体功能的拯救，运动行为延长和正常化。在SH-SY 5 Y神经母细胞瘤细胞中的补充实验显示，在存在葡萄糖脑苷脂酶和鞘磷脂酶联合抑制的情况下，α-突触核蛋白意外降低。我们的研究强调了任何假定的基因-基因相互作用的功能验证的重要性。
Biallelicglucocerebrosidase (GBA)mutations cause the lysosomal storage disorder Gaucher disease (GD), while heterozygousGBAvariants are the strongest and most common genetic risk factor for Parkinson disease (PD). An excessive burden of other lysosomal storage disorder gene variants, in particular forSMPD1(encoding for acid sphingomyelinase (ASM)) has also been reported in PD. However, it is unclear whetherGBAandSMPD1interact genetically. Zebrafish are an ideal vertebrate system to test for such interactions. We previously characterised agba1−/−mutant zebrafish line which displayed key hallmarks of human GD. In this work, we describe the biological interaction of combined glucocerebrosidase (GCase) and ASM deficiency ingba1−/−;smpd1−/−double mutant zebrafish. We observed a marked increase of glucosylceramide, ceramide and other key sphingolipids or their metabolites ingba1−/−;smpd1−/−compared togba1−/−orsmpd1−/−zebrafish. Unexpectedly, we observed a marked ameliorating effect of ASM inactivation on behaviour and disease duration ingba1−/−, resulting in a rescue of the characteristic motor phenotype and improved survival ingba1−/−;smpd1−/−. We identified complete rescue of mitochondrial respiratory chain function with normalisation of lipid peroxidation as the underlying mechanism for the observed rescue effect ingba1−/−;smpd1−/−. Combined ASM knockdown and GCase inhibition in human neuroblastoma SH-SY5Y cells unexpectedly lead to a decrease in monomeric α-synuclein, a key pathogenic protein in PD, which was independent of changes in macroautophagy flux. Our work highlights the importance of investigating the downstream functional consequences of gene-gene interactions in complex interacting pathways to determine any composite risk.Significance statementThe additive effect of genetic risk variants on disease incidence is a popular but frequently unproven hypothesis. Variants in the lysosomal disease genesglucocerebrosidase1(GBA1) andsphingomyelinase(SMPD1) are risk factors for Parkinson’s disease (PD). Zebrafish are ideally suited to study gene-gene interaction. We investigated a genetic interaction betweengba1−/−andsmpd1−/−ingba1−/−;smpd1−/−double-mutant zebrafish and observed an unexpected ameliorating effect of sphingomyelinase deficiency on thegba1−/−related phenotype with prolonged survival and normalisation of motor behaviour due to rescue of mitochondrial function. Complementing experiments in SH-SY5Y neuroblastoma cells revealed an unexpected lowering of α-synuclein in the presence of combined glucocerebrosidase and sphingomyelinase inhibition. Our study highlights the importance of functional validation for any putative gene-gene interactions.