This article is transferred from: People.cn-Yunnan Channel
People.cn, Kunming, July 20th (Reporter Li Faxing) The reporter learned from Kunming University of Science and Technology that a team led by Li Tianqing, Ai Zongyong and Ji Weizhi published a research paper titled Dissecting peri-implantation development using cultured human embryos and embryo-like assembloids in the internationally renowned journal Cell Research on the 17th. text. This study lays an important foundation for in-depth understanding of female infertility or fetal birth defects, and for exploring corresponding diagnosis and treatment strategies.
According to reports, human beings start from the fertilized egg formed by the combination of sperm and egg. The fertilized egg undergoes multiple cleavage and blastomere rearrangement, and a blastocyst is formed 6-7 days after fertilization. The human blastocyst is a hollow circular structure composed of about 200 cells, which implants into the uterine wall on the 6th to 7th day of the embryo (E6-7), and begins to develop after implantation. In the late blastocyst stage, the outer trophoblast cells gradually produce the placenta, the inner inner cell mass (ICM) splits into the hypoblast, which produces the yolk sac, and the epiblast differentiates into the three final germ layers, which eventually form the fetus to produce individuals. With the implantation of the blastocyst in the mother’s uterus, the embryo develops into the peri-implantation stage, and the epiblast and hypoblast gradually develop to form the three-dimensional structure of the double blastoderm, amniotic cavity, and yolk sac, and are specialized to produce post-implantation epiblast, extraembryonic endoderm/mesoderm, amnion, primordial germ cells, and primitive streaks and other cell lineages. For a long time, because the peri-implantation embryo is located in the mother's uterus and its size is small (hundreds of microns), relevant materials cannot be obtained for research, so it has been in a "black box" state.
In the process of embryonic development, the peri-implantation stage is a critical period that determines whether the embryo can develop normally. Implantation failure, pregnancy loss, and fetal birth defects are closely related to abnormal development of peri-implantation embryos, but the mechanisms are unclear. An important reason is the lack of understanding of the mechanism of embryonic development at the relevant stage. Therefore, an in-depth analysis of the development mechanism of human peri-implantation embryos will help to understand the relationship between embryo development and disease occurrence, thereby providing an important basis for the diagnosis and treatment of infertility (implantation failure or pregnancy loss) and fetal birth defects.
The study carried out by the research team of Kunming University of Science and Technology has for the first time drawn a complete cell map of the human peri-implantation embryo, and defined different cell lineages and the interaction between these lineages. On this basis, in order to make up for the ethical, embryo number and technical limitations of using human embryos for research, the researchers used human stem cells to develop a new artificially synthesized embryo, which for the first time reproduced the developmental characteristics, three-dimensional structure (double blastoderm, amniotic cavity and yolk sac) and cell lineage (extraembryonic endoderm/mesoderm, primordial germ cells and primitive streak) of human peri-implantation embryos.
This study is the first to systematically reveal the developmental dynamics, lineage characteristics, gene signals, and functions of key signaling pathways in the process of determining the fate of different lineages in human peri-implantation embryos. This study greatly advances the understanding of human peri-implantation embryo development. In addition, artificially synthesized embryos provide a new model for further exploration of lineage specification, signal interaction and tissue pattern after implantation of human embryos, and also provide a new platform for drug development and toxicology testing for abnormal embryo development.
