Can humans "reproduce asexually" through stem cells in the future?

Human life begins with a fertilized egg

On the 5th day of development, further division and cell differentiation produce a hollow structure called a blastocyst

The development of human embryos takes place in the mother's body, so it is difficult to study

For these reasons, knowledge about the key developmental steps of embryo formation at the blastocyst stage and early remodeling after implantation is still largely unknown

Recently, in a research report published in the international journal Nature Communications, scientists from the California Institute of Technology and other institutions have used human stem cells to create an embryo-like structure, which is similar to The natural embryo formed by the union of sperm and egg is different

This structure is made up of so-called pluripotent stem cells

Source: https:// 

These structures are formed by a special type of pluripotent stem cells, which can produce different types of cells, and then self-assemble to form a special structure, which is clearly reminiscent of embryonic shapes

These pluripotent stem cells were originally isolated from a real human embryo by other researchers and have been kept in a laboratory environment ever since

Before researchers can achieve the development accuracy of human stem cells and mouse stem cells, they have further work to do

In the current study, the researchers aim to develop a series of measures that will allow them to reconstruct the spatiotemporal lineage of human early development.

Researchers evaluated the multi-differentiation potential of hEPSCs on a 3D medium platform to simulate the fate of early embryonic cells

However, they also found that their cell line composition is not perfect, and these cells mainly adopt intermediate transcription states

Description of the blastocyst lineage

Image source: Nat Commun 12, 5550 (2021)

In this study, the hepsc-derived structure still has certain limitations in terms of molecular and epigenetic plasticity, which will lead to the weak activation of important genes (such as GATA3, SOX2, and SOX17 genes), leading to the failure of pedigree norms

Recently, researchers have described various alternative methods of using primitive or induced pluripotent stem cells to create human blastocyst-like structures

It also has a proper structure formation, and has certain cavities and internal cell clusters
.
The formation rate of human primitive blastocyst-like structures is 9.
4% ~ 12.
8%, and the formation rate of human induced pluripotent stem cells is 5.
8% ~ 18%
.

Although the structure of induced pluripotent stem cells appears to have morphology and transcriptional organization, scientists have questioned the identity of trophectoderm-like cells because they appear to be more similar to the reported amniotic membrane-like cells
.

This discovery, combined with the findings of this article, the researchers propose that in the human embryonic development model derived from stem cells, there is a certain disconnect between the underlying morphology and the cell behavior or the identity of the transcription cell
.

In this study, the researchers demonstrated the ability to produce similar but very different gene expression patterns
.
This highlights the uncoupling of morphology and gene expression in these models
.
Of course, these have yet to be further explored and studied by future generations
.

Cystic structures derived from hepsc may show implant-like morphological remodeling during culture
.

Image source: Nat Commun 12, 5550 (2021)
.
doi: 10.
1038 / s41467-021-25853-4

The ability to produce embryo-like structures from stem cells means that no additional donated embryos are required
.
In addition, such structures can be created in large numbers by researchers
.
Therefore, this model system can help understand the developmental process of early embryos without being limited by the limited availability of human embryos
.

For example, it may interfere with the expression of specific genes and study the effects of this on developmental processes
.
In addition, the system can also be used to understand how different cell components coordinate their development at very early stages, and the impact of this cell crosstalk in later developmental stages
.

The researchers proposed that hEPSCs are not equivalent to totipotent embryonic cells
.
They can only partially describe the offspring of embryonic cells
.
This may reflect the different molecular trajectories and the intermediate states adopted by these cells
.
This prompted the researchers to conduct this study
.

The production of inappropriately differentiated cells has been observed; nonetheless, these cells are capable of producing multicellular structures, exhibiting some key morphological features and patterns similar to early human natural embryos
.

Therefore, the system proposed by the researchers may provide another method that may be applied to a fully functional embryonic platform in vitro
.
In summary, the results of this article show that the new stem cell platform developed by researchers may provide new clues and insights for understanding stem cell models of embryonic development
.

Original search:

Sozen, B.
, Jorgensen, V.
, Weatherbee, BAT et al.
Reconstructing aspects of human embryogenesis with pluripotent stem cells.
Nat Commun 12, 5550 (2021).
doi: 10.
1038/s41467-021-25853-4