Fig. 4

Proteome analysis revealed that vWF in plasma EVs related to the stage of MDD. (A) SDS-PAGE gel with silver staining. The gels contain protein standard (lane 1) and healthy control participants (HCs) (lane 2–4). Coverage of above 250 kDa protein (red dashed line) in plasma EV obtained HCs analyzed by LC-MS. (B) List of polypeptides within above 250 kDa protein identified in the proteomics analysis. (C) Representative image of western blotting for vWF protein (Molecular weight, 260 kDa) in plasma EVs (400 ng) obtained from HCs (n = 5) and patients with MDD (MDD, n = 5). (D) Representative image of western blotting for plasma EVs proteins (400 ng) in HCs (n = 5) with or without sialidase (SA) treatment. We detected the PVDF membrane strips with an antibody against human vWF. (E) Densitometric measurement of vWF antigen (Ag) in plasma EVs from HCs (n = 20) and patients with MDD (n = 21) by sandwich ELISA. The absorbance read at 450 nm. (F) ROC curve analysis using vWF Ag in plasma EVs for diagnosis of MDD. A cutoff value is 0.276 µg/mL by the closest-top-left method. (G) Paired box plots depicting individual patient data between patients with MDD (n = 10) in depressive state (DP) and remission state (REM). (H) ROC curve analysis using vWF Ag in plasma EVs for diagnosis of MDD. A cutoff value is 0.606 µg/mL by the closest-top-left method. We used Mann–Whitney U test or Student t-test to test for significance. **p < 0.01.