Plasma metabolome and skin proteins in Charcot-Marie-Tooth 1A patients

ObjectiveCharcot-Marie-Tooth 1A (CMT1A) disease is the most common inherited neuropathy that lacks of therapy and of molecular markers to assess disease severity. Herein, we have pursued the identification of potential biomarkers in plasma samples and skin biopsies that could define the phenotype of CMT1A patients at mild (Mi), moderate (Mo) and severe (Se) stages of disease as assessed by the CMT neuropathy score to contribute to the understanding of CMT pathophysiology and eventually inform of the severity of the disease.MethodsWe have used: (i) a high-throughput untargeted metabolomic approach of plasma samples in a cohort of 42 CMT1A patients and 15 healthy controls (CRL) using ultrahigh liquid chromatography coupled to mass spectrometry and (ii) reverse phase protein microarrays to quantitate the expression of some proteins of energy metabolism and of the antioxidant response in skin biopsies of a cohort of 70 CMT1A patients and 13 healthy controls.ResultsThe metabolomic approach identified 194 metabolites with significant differences among the four groups (Mi, Mo, Se, CRL) of samples. A multivariate Linear Discriminant Analysis model using 12 metabolites afforded the correct classification of the samples. These metabolites indicate an increase in protein catabolism and the mobilization of membrane lipids involved in signaling inflammation with severity of CMT1A. A concurrent depletion of leucine, which is required for the biogenesis of the muscle, is also observed in the patients. Protein expression in skin biopsies indicates early loss of mitochondrial and antioxidant proteins in patients’ biopsies.ConclusionThe findings indicate that CMT1A disease is associated with a metabolic state resembling inflammation and sarcopenia suggesting that it might represent a potential target to prevent the nerve and muscle wasting phenotype in these patients. The observed changes in metabolites could be useful as potential biomarkers of CMT1A disease after appropriate validation in future longitudinal studies.

本数据集旨在探究血浆样本和皮肤活检中潜在的生物标志物，以界定Charcot-Marie-Tooth 1A（CMT1A）疾病患者的轻度（Mi）、中度（Mo）和重度（Se）阶段的表型，评估标准为CMT神经病变评分。本研究旨在加深对CMT病理生理学的理解，并最终为疾病的严重程度提供信息。研究方法包括：采用超高效液相色谱联用质谱技术，对42例CMT1A患者和15例健康对照者（CRL）的血浆样本进行高通量非靶向代谢组学分析；以及采用反向相蛋白微阵列技术，对70例CMT1A患者和13例健康对照者的皮肤活检样本中某些能量代谢和抗氧化反应相关蛋白的表达进行定量分析。研究结果显示，代谢组学方法在四组样本（Mi、Mo、Se、CRL）中识别出194种具有显著差异的代谢物。使用12种代谢物构建的多变量线性判别分析模型，能够正确分类样本。这些代谢物表明蛋白质分解代谢增加，与CMT1A疾病严重程度相关的信号炎症相关膜脂质动员。同时观察到肌生成所需的亮氨酸的消耗也在患者中减少。皮肤活检中的蛋白表达表明患者活检样本中早期线粒体和抗氧化蛋白的丢失。结论指出，CMT1A疾病与类似炎症和肌肉萎缩的代谢状态相关，这表明它可能成为预防患者神经和肌肉萎缩表型的潜在靶点。观察到的代谢物变化，在未来的纵向研究中经过适当的验证后，可能作为CMT1A疾病的潜在生物标志物。