News | IMBA Study: Molecular Signals in Early Embryonic Development Originate from the Embryo
Using a blastoid model, researchers at Austria's Institute of Molecular Biotechnology (IMBA) revealed how molecular signals from the embryo during its earliest stages affect placental development and prepare the uterus. The findings provide important scientific evidence for understanding human fertility and were published in Cell Stem Cell.
Background:
Early embryos are generally considered very fragile and dependent on external support. However, using an innovative blastoid model, the IMBA team found that embryos have a strong capacity to guide their own development from the earliest stages. The study showed that embryos can release molecular signals that direct the formation of the future placenta and prepare the uterus to provide a suitable environment. This finding challenges the traditional view that early embryos only require external support.
Blastoids are in vitro models of the blastocyst, which forms during the first few days after fertilization, and are grown from embryonic stem cells. The IMBA team first developed blastoids from mouse stem cells in 2018 and successfully created them from human stem cells in 2021. This innovative model provides an ethical alternative for embryo research and has supported several major discoveries.
Breakthrough Findings:
Using mouse blastoids, researchers found that the earliest part of the embryo, consisting of about 10 cells, can direct the formation of the future placental component, consisting of about 100 cells, and induce changes in uterine tissue. IMBA laboratory director Nicolas Rivron said, "Through these signals, the embryo invests in its own future: it promotes the formation of tissues that support its development. The embryo controls the process and directs the creation of a supportive environment."
The team found that epiblast cells in the developing embryo secrete molecules that promote the self-renewal and proliferation of trophoblast cells, which later form the placenta. This process is fundamental to placental development. These molecules also cause trophoblast cells to secrete two other molecules, WNT6 and WNT7B, which signal the uterus to form a protective layer around the embryo.
Rivron explained, "Other researchers previously found that WNT molecules are involved in the uterine response, but we are the first to show that WNT6 and WNT7B are secreted by trophoblast cells in the blastocyst and signal the uterus to respond. This finding is significant because we have confirmed that both molecules are also present in trophoblast cells in human blastocysts."
Significance and Outlook:
To validate the finding, the team conducted implantation experiments with blastoids in mice and found that implantation efficiency was much higher than expected. Co-first author and Rivron laboratory postdoctoral researcher Yucheng Jin said, "We were very surprised to find that blastoids implanted in the uterus with very high efficiency. By changing properties of the trophoblast cells, such as WNT6/7B secretion levels, we could significantly alter the size of the protective uterine layer."
Implantation is a major limiting stage in human pregnancy, with approximately 50% of pregnancies failing at this point. Because WNT6 and WNT7B are also present in human blastocysts, researchers believe the finding may help explain why some pregnancies encounter problems. Rivron added, "We are repeating this experiment with human blastoids and uterine cells, entirely in culture dishes, to assess whether these fundamental developmental principles are conserved across species. Ultimately, these findings may support improvements in IVF procedures and the development of fertility treatments and contraceptives."
Interdisciplinary Collaboration and Social Impact:
Co-first author Viktoria Holzmann said, "Understanding these fundamental principles of embryonic development will help women gain greater control over their fertility. This may not only improve family planning but also advance gender equality in society."
News | IMBA Study: Molecular Signals in Early Embryonic Development Originate from the Embryo
News | IMBA Study: Molecular Signals in Early Embryonic Development Originate from the Embryo
Using a blastoid model, researchers at Austria's Institute of Molecular Biotechnology (IMBA) revealed how molecular signals from the embryo during its earliest stages affect placental development and prepare the uterus. The findings provide important scientific evidence for understanding human fertility and were published in Cell Stem Cell.
Background:
Early embryos are generally considered very fragile and dependent on external support. However, using an innovative blastoid model, the IMBA team found that embryos have a strong capacity to guide their own development from the earliest stages. The study showed that embryos can release molecular signals that direct the formation of the future placenta and prepare the uterus to provide a suitable environment. This finding challenges the traditional view that early embryos only require external support.
Blastoids are in vitro models of the blastocyst, which forms during the first few days after fertilization, and are grown from embryonic stem cells. The IMBA team first developed blastoids from mouse stem cells in 2018 and successfully created them from human stem cells in 2021. This innovative model provides an ethical alternative for embryo research and has supported several major discoveries.
Breakthrough Findings:
Using mouse blastoids, researchers found that the earliest part of the embryo, consisting of about 10 cells, can direct the formation of the future placental component, consisting of about 100 cells, and induce changes in uterine tissue. IMBA laboratory director Nicolas Rivron said, "Through these signals, the embryo invests in its own future: it promotes the formation of tissues that support its development. The embryo controls the process and directs the creation of a supportive environment."
The team found that epiblast cells in the developing embryo secrete molecules that promote the self-renewal and proliferation of trophoblast cells, which later form the placenta. This process is fundamental to placental development. These molecules also cause trophoblast cells to secrete two other molecules, WNT6 and WNT7B, which signal the uterus to form a protective layer around the embryo.
Rivron explained, "Other researchers previously found that WNT molecules are involved in the uterine response, but we are the first to show that WNT6 and WNT7B are secreted by trophoblast cells in the blastocyst and signal the uterus to respond. This finding is significant because we have confirmed that both molecules are also present in trophoblast cells in human blastocysts."
Significance and Outlook:
To validate the finding, the team conducted implantation experiments with blastoids in mice and found that implantation efficiency was much higher than expected. Co-first author and Rivron laboratory postdoctoral researcher Yucheng Jin said, "We were very surprised to find that blastoids implanted in the uterus with very high efficiency. By changing properties of the trophoblast cells, such as WNT6/7B secretion levels, we could significantly alter the size of the protective uterine layer."
Implantation is a major limiting stage in human pregnancy, with approximately 50% of pregnancies failing at this point. Because WNT6 and WNT7B are also present in human blastocysts, researchers believe the finding may help explain why some pregnancies encounter problems. Rivron added, "We are repeating this experiment with human blastoids and uterine cells, entirely in culture dishes, to assess whether these fundamental developmental principles are conserved across species. Ultimately, these findings may support improvements in IVF procedures and the development of fertility treatments and contraceptives."
Interdisciplinary Collaboration and Social Impact:
Co-first author Viktoria Holzmann said, "Understanding these fundamental principles of embryonic development will help women gain greater control over their fertility. This may not only improve family planning but also advance gender equality in society."
Story source:
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