Cutting edge Seminar
※ Zoom online/ Please check the URL on “HIGO Cutting-Edge Seminar” at Moodle
Speaker: Isao Matsuo (Department of Molecular Embryology Research Institute, Osaka Women’s and Children’s Hospital Osaka Prefectural Hospital Organization)
Title: Intrauterine mechanical environment for early mammalian morphogenesis
Date&Time: 13 Feb. (Wed.) 2021, 12:00- 13:00
Venue: Zoom online/ Please check the URL on “HIGO Cutting-Edge Seminar” at Moodle
SUMMARY
Embryogenesis of a placental mammal proceeds in utero with the support of a nutrient supply and gas exchange from maternal tissues. In fact, recent advances in ex utero culture of mouse embryos demonstrate embryo-autonomous development of mammalian early embryogenesis. Given that the orderly development of implanted embryos in ex utero culture in time and space is still challenging, non-embryo autonomous mechanisms mediated by maternal tissues except such a nutrient supply seem to be involved in early mouse embryogenesis. Mouse embryos morphologically change from the spherical shape of pre-implanted blastocysts to the elongated egg-cylinder shape of post-implanted embryos. This morphological change is closely linked to mouse primary axis polarization, i.e., the emergence of distal visceral endoderm. However, the contribution of the mechanical environment provided by the uterus to embryogenesis remains unaddressed. Notably, how intrauterine pressures are produced, accurately adjusted, and exerted on embryos are completely unknown.
Here, we found that intrauterine pressures were produced by uterine smooth muscle contractions, showing the highest and most frequent periodic peaks just after implantation and contributed to egg-cylinder morphogenesis and consequent axis polarization as an important biomechanical environment in utero. Additionally, Reichert’s membrane, a specialized basement membrane that wraps around the implanted mouse embryo, played a crucial role as a shock absorber to protect embryos from the excess intrauterine pressures. Mechanistically, such pressures were adjusted within the sealed space between embryo and uterus created by Reichert’s membrane. Thus, we propose the buffer space sealed by Reichert’s membrane cushions and disperses intrauterine pressures for early mammalian development.
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