Study of recognition mechanism between mother and embryo using the xeno-hybrid placenta

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K19267
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: Isotani Ayako 奈良先端科学技術大学院大学, 先端科学技術研究科, 准教授 (20444523)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 母子間認識 / 異種 / 胎盤 / 脱落膜 / ハイブリッド

Outline of Final Research Achievements

If rat embryos are transferred into an immunodeficient surrogate mouse mother, they do not make it a pregnancy. This suggested that there was species-specific recognition between the mother and embryo. In this study, rat embryos, which were transferred into the immunodeficient surrogate mice, survived at embryonic day 5.5, but the embryos were small in size, and the extraembryonic tissues were not fully proliferated. Furthermore, no rat cells contributed to the trophoblast lineage when interspecies chimeric embryos produced from mouse and rat 8-cell stage embryos were transferred into immunodeficient surrogate mice. These findings suggested that trophoblast proliferation and differentiation were not induced by the interaction with trophoblasts of different species and that interaction with the decidua derived from the mother may be important.

Free Research Field

実験動物学

Academic Significance and Societal Importance of the Research Achievements

哺乳類において、妊娠の成立には、母体の子宮内膜と胚が相互に作用しあう母子間相互作用が必要不可欠である。最初の母子間相互作用である着床は、子宮に到達した胚（最外層に位置する栄養膜細胞)からのシグナルを受け、子宮内膜が肥厚して胚を包み込むように脱落膜が形成されてはじまる。本研究で、免疫不全マウスにラット胚や異種間集合キメラ胚を移植した実験により、脱落膜形成後に栄養芽細胞を含む異種の胚体外組織の増殖不全が認められ、母子間相互作用は、着床時だけでなく、脱落膜形成後も胚体外組織の増殖に重要であることが示された。このことは、原因不明の流産を繰返す習慣性流産の原因解明につながると期待できる。