Effect Of ECAT1 And Granulosa Cell On Oocyte Development

Mammalian egg generation is a complex process,starting with primordial germ cell specialization to egg ovulation.On the world,15-20%of couples suffer from infertility.Among the infertile,half are females and oocyte developmental abnormalities are among the most important pathogenic factors.To explore the impact of EC AT1 and granulosa cell on oocyte development and provide theoretical support for assisted reproduction,we have carried out the following studies:1.Oocytes contain a large number of maternal genes that may play significant roles in oocyte maturation and early embryonic development.However,so far,the functions of many maternal genes have been only studied in experimental animals such as mouse,and rarely studied in human oocytes.ECAT1 is a part of SCMC and its functional role has been elucidated in mouse,but not in human oocyte maturation,fertilization and early embryonic development.We found that EC ATI mRNA was highly expressed in human ovaries,and ECAT1 protein was located in the cytoplasm of human oocytes and early embryos.ECAT1 RNAi in human GV oocytes resulted in the maturation arrest.Following ICSI,the oocytes after ECAT1 RNAi showed obvious abnormalities in fertilization,cleavage and embryonic development.Therefore,this study reveals a role of ECAT1 in human oocyte and embryonic development,and provides a molecular marker for the clinical diagnosis of infertility caused by abnormal oocyte or embryonic development.2.Improvement on the quality of oocyte maturation in vitro(IVM)is the focus of current research due to the need of assisted reproductive and scientific research on oocyte development.The quality of IVM oocytes is lower than that of oocytes maturated in vivo(IVO)and the co-culture of oocytes with granulosa cells can improve oocytes quality,however,the mechanism in which is still unknown.The IVO oocytes,naked IVM oocytes,and co-cultured oocytes were sequenced by single cell sequencing technology respectively.The results showed that co-culture of oocytes with granulosa cells could reduce the differences of transcription caused by IVM in oocytes.It was found by KEGG analysis of the differentially expressed genes that IVM could lead to abnormalities of lysosomes,glycerol phospholipid metabolism,tricarboxylic acid cycle,ribosome assembly,protein folding and autophagy,all of which can be reduced by co-culture of oocytes with granulosa cells.