Dysregulated pathways and potential biomarkers in dermatomyositis plasma-derived extracellular vesicles

Extracellular vesicles (EVs) have been implicated in dermatomyositis pathogenesis, but their protein content is not well characterized. We collected EVs from plasma, isolated them using sequential ultracentrifugation and size-exclusion chromatography, and analyzed their content by mass spectrometry. Protein biomarkers that distinguish patients with DM from controls were assessed using the random forest algorithm. Out of these, select proteins were identified as highly potential disease biomarkers, and their abundance was confirmed in a separate cohort using ELISA. Thirty-five proteins were differentially expressed and 67 were uniquely detected in the patient cohort. The following proteins displayed the most significant differential expression and were validated in a separate cohort of patients: The antioxidant enzyme glutathione peroxidase 3 (GPX3), and two complement proteins, Ficolin-2 (FCN2) and SERPING1 were less abundant in patients' EVs. Surfactant protein B (SFTPB) was expressed almost exclusively in patients with lung disease, suggesting that it may be a marker for pulmonary involvement. In summary, we identified GPX3, FCN2 and SERPING1 as biomarkers in DM. Our data underline the importance of oxidative stress and complement regulation in DM. SFTPB is a potential biomarker for pulmonary involvement.

细胞外囊泡（Extracellular vesicles, EVs）已被证实与皮肌炎的发病机制相关，但其蛋白质组成尚未得到充分表征。我们从血浆中收集细胞外囊泡，采用顺序超速离心结合尺寸排阻色谱法进行分离，并通过质谱技术对其内容物开展分析。利用随机森林算法评估了可区分皮肌炎患者与健康对照者的蛋白质生物标志物。从中筛选出数种具有极高潜力的疾病相关生物标志物，并通过ELISA在独立队列中验证了它们的表达丰度。本研究共鉴定出35种差异表达蛋白，另有67种蛋白仅在患者队列中被检测到。其中，以下蛋白呈现出最为显著的差异表达，并在另一组患者队列中得到了验证：抗氧化酶谷胱甘肽过氧化物酶3（GPX3），以及两种补体蛋白——纤维胶凝蛋白2（FCN2）与SERPING1，它们在患者来源的细胞外囊泡中表达丰度更低。表面活性蛋白B（SFTPB）几乎仅在伴有肺部受累的皮肌炎患者中表达，提示其可作为肺部累及的潜在标志物。综上，本研究鉴定出GPX3、FCN2及SERPING1可作为皮肌炎的生物标志物。我们的研究结果凸显了氧化应激与补体调控在皮肌炎发病机制中的重要性。SFTPB则有望成为皮肌炎肺部累及的潜在生物标志物。