New Insights into Motor Neuron Disease

描述（由申请人提供）：本研究将分析运动神经元疾病（MND）的新原因。我们发现，在神经病变靶酯酶（NTE）基因突变导致常染色体隐性遗传MND（NTE-MND）。我们进一步表明，疾病特异性NTE突变存在于肌萎缩侧索硬化症（ALS）受试者的一个子集。NTE是一种膜磷脂酶，在有机磷（OP）诱导的迟发性神经病（OPIDN）中起关键作用。最近的研究表明，NTE可以调节cAMP依赖性蛋白激酶（也称为“蛋白激酶A”或PKA）。分析NTE突变的发病机制将为包括ALS在内的运动神经元疾病的发病机制提供新的见解。我们将确定“明显非家族性”ALS和海湾战争ALS受试者中NTE基因变异的性质和频率。我们将通过评估ALS特异性NTE突变对NTE酯酶活性、溶血磷脂酰胆碱（LPC）毒性和拯救sws果蝇（NTE-MND的无脊椎动物模型）神经变性的能力的影响来确定ALS特异性NTE突变的功能意义。我们将研究NTE作为PKA调节因子的功能，以及评估致病性NTE突变对这种调节的影响。我们将利用NTE-MND受试者的成纤维细胞培养物和诱导多能干细胞（IPS）方法来创建运动神经元培养物作为NTE-MND的体外模型。（类似的方法已被证明在研究其他两种运动神经元疾病，SOD 1突变ALS和脊髓性肌萎缩症中有用）。我们将研究NTE突变的发病机制，在这个体外系统，包括LPC毒性，PKA的异常调节和神经毒性OP化合物的脆弱性。从临床到实验室的研究将有助于我们进一步了解NTE-MND、ALS和相关运动神经元疾病的发病机制和最终治疗方法。缩略语：肌萎缩侧索硬化症（ALS）;毒死蜱氧磷（CPO）;环AMP（cAMP）;环AMP依赖性蛋白激酶（PKA）;二异丙基氟磷酸盐（DFP）;诱导多能干细胞（IPS）; 50%抑制浓度（IC 50）溶血磷脂酰胆碱（LPC）;米帕福克斯（MIP）;运动神经元疾病（MND）;神经病靶向酯酶（NTE），有机磷：OP;环AMP依赖性蛋白激酶（PKA）;瑞士奶酪蛋白（SWS）; sws =瑞士奶酪基因和果蝇突变株。

DESCRIPTION (provided by applicant): This investigation will analyze a novel cause of motor neuron disease (MND). We discovered that mutations in the neuropathy target esterase (NTE) gene cause autosomal recessive MND (NTE-MND). We further showed that disease-specific NTE mutations are present in a subset of subjects with amyotrophic lateral sclerosis (ALS). NTE is a membrane phospholipase that plays a critical role in organophosphorous (OP) induced delayed neuropathy (OPIDN). Recent studies indicate that NTE may regulate cAMP-dependent protein kinase (also known as "protein kinase A" or PKA). Analyzing NTE-mutation pathogenesis will provide fresh insights into mechanisms underlying motor neuron diseases including ALS. We will determine the nature and frequency of NTE gene variation in "apparently nonfamilial" ALS and Gulf War ALS subjects. We will determine the functional significance of ALS-specific NTE mutations by assessing their effect on NTE esterase activity, lysophosphatidylcholine (LPC) toxicity, and ability to rescue neurodegeneration in sws Drosophila, an invertebrate model of NTE-MND. We will investigate NTE function as a PKA regulatory factor; as well as assess the effect of pathogenic NTE mutations on this regulation. We will utilize fibroblast cultures from NTE-MND subjects and induced pluripotent stem (IPS) cell methods to create motor neuron cultures as in vitro model of NTE-MND. (A similar approach has proven useful in studying two other motor neuron diseases, SOD1-mutation ALS and spinal muscular atrophy). We will examine mechanisms of NTE-mutation pathogenesis in this in vitro system including LPC toxicity, aberrant regulation of PKA and vulnerability to neurotoxic OP compounds. Insights gained in this bedside-to-bench investigation will advance our knowledge of the pathogenesis and ultimately treatment for NTE-MND, ALS, and related motor neuron disorders. Abbreviations: Amyotrophic Lateral Sclerosis (ALS); chlorpyrifos oxon (CPO); cyclic AMP (cAMP); cyclic AMP dependent protein kinase (PKA); diisopropyl fluorophosphates (DFP); Induced Pluripotent Stem (IPS) cell; 50% inhibitory concentration (IC50) lysphophosphatidyl choline (LPC); mipafox (MIP); Motor Neuron Disease (MND); Neuropathy Target Esterase (NTE), Organophosphorous: OP; cyclic AMP dependent protein kinase (PKA); Swiss Cheese protein (SWS); sws = swiss cheese gene and Drosophila mutant strain.