Isolation and identification of placental exosomes from maternal serum / 医学研究生学报

ABSTRACT

Objective During pregnancy , exosomes can be released from the placenta into maternal circulation and play im-portant roles in normal pregnancy or placenta-related diseases .We aimed to establish a simple and efficient method for isolating and i-dentifying placental exosomes from maternal serum and lay a foundation for the studies of pregnancy -related diseases . Methods Using sucrose gradient centrifugation with 8% PEG6000 precipitation twice , we isolated and purified placenta-derived exosomes from normal maternal serum and detected their molecular markers CD 63 , CD81 and PLAP by Western blot , followed by silver staining anal-ysis of the protein profile of the exosome pellet .We identified the morphology of the placenta-derived exosomes by transmission electron microscopy ( TEM) and measured the size and distribution of the particles by dynamic light scattering ( DLS) . Results Silver stai-ning of the protein profiles of the exosomes after sucrose gradient centrifugation clearly revealed the bands of the protein molecules . Western blot showed the expressions of CD 63, CD81, and PLAP in the 21-34%density layer, which demonstrated the presence of serum placental exosomes mainly in the 1.09-1.16 g/mL density layer.TEM exhibited that the placenta-derived exosomes were round or oval cup-shaped, specifically expressing PLAP, and the particles were uniform in size, with a mean diameter of (41.79 ±11.94) nm. Conclusion A simple, fast, and efficient method was successfully established for isolating placenta-derived exosomes from ma-ternal serum, which provides a basis for studying the roles of placental exosomes in normal pregnancy and placenta -related diseases.