SMN Protein Can Be Reliably Measured in Whole Blood with an Electrochemiluminescence (ECL) Immunoassay: Implications for Clinical Trials.
SMN Protein Can Be Reliably Measured in Whole Blood with an Electrochemiluminescence (ECL) Immunoassay: Implications for Clinical Trials.
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DOI：
10.1371/journal.pone.0150640
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Paushkin S
中科院分区：
文献类型：
--
作者：
Zaworski P;von Herrmann KM;Taylor S;Sunshine SS;McCarthy K;Risher N;Newcomb T;Weetall M;Prior TW;Swoboda KJ;Chen KS;Paushkin S
脊髓性肌萎缩症(SMA)是由编码存活运动神经元(SMN)蛋白的存活运动神经元1(SMN1)基因缺陷引起的。目前临床上开发的大多数SMA的治疗方法旨在增加SMN蛋白的表达，需要能够量化可到达组织中SMN蛋白水平增加的敏感方法。我们建立了一种灵敏的基于电化学发光的免疫分析方法，用于检测全血和其他组织中的SMN蛋白，最小体积要求为5μL。用该方法检测SMA患者和健康对照组全血中SMN蛋白水平，发现SMN蛋白水平与SMN拷贝数有关，拷贝数为4的SMA患者SMN蛋白水平高于拷贝数为2和3的SMA患者。在四周的健康个体中，SMN蛋白水平没有显著变化，也不受昼夜节律的影响。几乎一半的SMN蛋白存在于血小板中。我们发现，在C/C等位基因小鼠中，SMN蛋白水平在新生阶段很高，在出生后的头几周下降，然后在成年期保持稳定。重要的是，中枢神经系统中的SMN蛋白水平与C/C等位基因小鼠全血中的SMN水平相关。这些发现对测量SMN上调治疗后全血中SMN蛋白的诱导有一定意义。
Spinal muscular atrophy (SMA) is caused by defects in the survival motor neuron 1 (SMN1) gene that encodes survival motor neuron (SMN) protein. The majority of therapeutic approaches currently in clinical development for SMA aim to increase SMN protein expression and there is a need for sensitive methods able to quantify increases in SMN protein levels in accessible tissues. We have developed a sensitive electrochemiluminescence (ECL)-based immunoassay for measuring SMN protein in whole blood with a minimum volume requirement of 5μL. The SMN-ECL immunoassay enables accurate measurement of SMN in whole blood and other tissues. Using the assay, we measured SMN protein in whole blood from SMA patients and healthy controls and found that SMN protein levels were associated with SMN2 copy number and were greater in SMA patients with 4 copies, relative to those with 2 and 3 copies. SMN protein levels did not vary significantly in healthy individuals over a four-week period and were not affected by circadian rhythms. Almost half of the SMN protein was found in platelets. We show that SMN protein levels in C/C-allele mice, which model a mild form of SMA, were high in neonatal stage, decreased in the first few weeks after birth, and then remained stable throughout the adult stage. Importantly, SMN protein levels in the CNS correlated with SMN levels measured in whole blood of the C/C-allele mice. These findings have implications for the measurement of SMN protein induction in whole blood in response to SMN-upregulating therapy.