309 PROTEOMIC ANALYSIS OF THE BLASTOCOEL FLUID AND REMAINING CELLS OF BOVINE BLASTOCYSTS

Human embryonic stem cells (hESC) are derived from the human blastocystand possess the potential to differentiate into any cell type present in the adult human body. Human ESC are considered to have great potential in regenerative medicinefor the future treatment of severe diseases and conditions such as Parkinson’s disease, diabetes, and spinal cord injury. One of today’s challenges in regenerative medicineis to define proper culture conditions for hESC. The natural milieu in the blastocystmay provide clues on how to improve culture conditions, and the aim of the present study was to determine the proteome of the blastocoelfluid and the remaining cells of bovine blastocysts. Bovine blastocystswere produced by in vitro fertilization of oocytes retrieved from slaughterhouse ovaries. The blastocoelfrom 195 blastocysts(1–8 nL per blastocyst) were isolated by micromanipulationand analysed by nano-HPLC tandem mass spectrometry along with the remaining cells of the blastocyst. Searching the mass spectrometry data against a combined bovine database (SwissProt/TrEMBL), we identified 263 proteins in the blastocoelfluid and 1606 proteins in the cellular compartmentof the blastocyst. A Venn diagramshowed 124 proteins in overlap between the two compartments of the blastocyst. Several heat shock proteins and specific antioxidants were identified in both the blastocoeland cell material. A selection of proteins identified in the blastocoelfluid is to be tested on hESC in cell culture experiments, with proliferation of undifferentiated cells as the primary endpoint. The results from this study provide new knowledge about early mammalian preimplantation development, and the data can be used in the continued pursue of improving culture conditions for hESC, which further facilitates the clinical application of these cells.