Anti grp75

Total proteins were isolated from WJ‐MSC, hNPC and WJ‐MSC‐derived EV lysates using the radioimmunoprecipitation assay buffer (RIPA buffer; Sigma) for 30 min on ice, cleared by centrifugation for 30 min at 12 000 g at 4°C for 30 min and quantified using the detergent compatible (DC) protein assay kit (Bio‐Rad, Hercules, CA, USA). Each sample was loaded on 4%–12% SDS‐PAGE gels, transferred onto nitrocellulose membranes through the Trans‐Blot Turbo Transfer System (Bio‐Rad) and incubated in a blocking buffer (TBST 1X with 5% nonfat dry milk) for 1 h. Membranes were incubated with a primary antibody overnight shaking at 4°C in TBST 1X with 1% nonfat dry milk. Anti‐CD63 (mouse, 1:1000, Invitrogen), anti‐CD9 (mouse, 1:1000, Invitrogen), anti‐TSG101 (mouse, 1:1000, Invitrogen), and anti‐GRP75 (rabbit, 1:2000, Proteintech, Thermo Fisher Scientific), anti‐COL1A1 (rabbit, 1:1000; Abcam), anti‐COL2A1 (rabbit, 1:1000, Abcam), and anti‐tubulin (1:5000, Abcam, Cambridge, UK) primary antibodies were utilized. Anti‐mouse and anti‐rabbit HRP‐conjugated antibodies (1:10000, Abcam) were used and chemiluminescence signals were detected using ChemiDoc (Bio‐Rad) and Quantity One software (Bio‐Rad) to quantify the signal intensity of different bands.