q&more
My watch list
my.chemie.de  
Login  

News

Embryonic development in a Petri dish

3D cell culturing technique could replace mouse embryos

© Dennis Schifferl, Adriano Bolondi, Polly Burton, Jesse Veenvliet - MPI f. Mol. Genet.

Collage of fluorescent microscopic images of Trunk-Like-Structures generated from stem cells at several stages of their development in a dish. The trunk-like-structures have been stained for expression of different key developmental genes (colors). Some have been treated with drugs that target important developmental pathways, which leads to neural tube defects and overproduction of somites arranged like a bunch-of-grapes (e.g. top left).

14-Dec-2020: By growing mouse stem cells in a special gel, a Berlin research team succeeded to grow structures similar to parts of an embryo. The trunk-like structures develop the precursors for neural, bone, cartilage and muscle tissues from cellular clumps within five days. This could allow the investigation of the effects of pharmacological agents more effectively in the future – and on a scale that would not be possible in living organisms.

It would certainly spare mothers the hardships of pregnancy, but mammals do not grow in eggs. In a way, this is also impractical for science. While embryos of fish, amphibians or birds can be easily watched growing, mammalian development evades the gaze of the observer as soon as the embryo implants into the uterus. This is precisely the time when the embryo undergoes profound changes in shape and develops precursors of various organs – a highly complex process that leaves many questions unanswered.

But now a research team at the Max Planck Institute for Molecular Genetics in Berlin succeeded in replicating a central phase of embryonic development in a cell culture approach by growing the core portion of the trunk from mouse embryonic stem cells for the first time. The method recapitulates the early shape-generating processes of embryonic development in the Petri dish.

The structures are roughly a millimeter in size and possess a neural tube from which the spinal cord would develop. Furthermore, they have somites, which are the precursors of skeleton, cartilage and muscle. Some of the structures even develop the precursors of internal organs such as the intestine. After about five days, the parallels to normal development end.

“This model of embryonic development starts a new era,” says Bernhard G. Herrmann, Director at the Max Planck Institute for Molecular Genetics and Director of the Institute of Medical Genetics at Charité – Universitätsmedizin Berlin. “This allows us to observe embryogenesis of the mouse directly, continuously, and with large parallel numbers of samples – which would not be possible in the animal.”

It is considered quite easy to isolate early embryos from the tube or the uterus and grow them in the Petri dish, as long as they are still free to move. But once the embryo has implanted in the endometrium, isolation becomes extremely difficult. “We can obtain more detailed results more quickly, and without the need for animal research,” says Alexander Meissner, who like Herrmann is Director at the Max Planck Institute for Molecular Genetics and jointly supervised the study. “Of the more complex processes such as morphogenesis, we usually only get snapshots – but this changes with our model.”

A gel provides support and spatial orientation

So far, it has only been possible to grow cell clusters from embryonic stem cells, so-called gastruloids. “Cellular assemblies in gastruloids develop to a similar extent like in our trunk-like structures, but they do not assume the typical appearance of an embryo” says Jesse Veenvliet, one of the two lead authors of the study. “The cell clusters lack the signals that trigger their organization into a meaningful arrangement.”

In the cell culture, the required signal is generated by a special gel that mimics the properties of the extracellular matrix. This jelly-like substance consists of a complex mixture of extended protein molecules that is secreted by cells and is found throughout the body as an elastic filling material, especially in connective tissues. The utilization of this gel is the crucial “trick” of the new method. “The gel provides support to the cultured cells and orients them in space; they can distinguish inside from outside, for example,” says Veenvliet. It also prevents secreted molecules such as the matrix protein fibronectin from leaking into the cell culture medium. “The cells are able to establish better communication, which leads to better self-organization.”

Cells with similar properties as in the embryo

After four to five-days, the team dissolved the structures into single cells and analyzed them individually. “Even though not all cell types are present in the trunk-like structures, they are strikingly similar to an embryo of the same age,” says Adriano Bolondi, who is also lead author of the paper. Together with bioinformatician Helene Kretzmer, Bolondi and Veenvliet compared the genetic activity of the structures with actual mouse embryos. “We found that all essential marker genes were activated at the right time in the right places in the embryoids, with only a small number of genes being out of line,” says Bolondi.

The researchers introduced a mutation with known developmental effects into their model and could recreate the results from “real” embryos, further validating their model. They also provide examples of manipulating the developmental process with chemical agents.

Original publication:
Jesse V Veenvliet, Adriano Bolondi et al.; "Mouse embryonic stem cells self-organize into trunk-like structures with neural tube and somites"; Science; 2020

Facts, background information, dossiers

  • embryo development
  • 3D cell cultures
  • stem cells
  • embryos

More about MPI für molekulare Genetik

  • News

    A molecular switch for the X chromosome

    A large number of genes have to be switched on or off at different times during development. A particular challenge occurs when two copies of the same gene must acquire opposing states of activation within the same cell, as it is the case, for example, for the two X chromosomes in the femal ... more

More about Max-Planck-Gesellschaft

  • News

    Cells talk at each other to specialize different functions

    During development, cells must specialize their function in a well defined timeline: formation of different tissues must be coordinated from a pile of cells. The research group led by Aneta Koseska (former Max Planck Institute of Molecular Physiology (MPI), CAESAR Bonn) has now developed a ... more

    Genotoxic E. coli “caught in the act”

    Escherichia coli bacteria are constitutive members of the human gut microbiota. However, some strains produce a genotoxin called colibactin, which is implicated in the development of colorectal cancer. While it has been shown that colibactin leaves very specific changes in the DNA of host c ... more

    Keeping Sperm Cells on Track

    One essential component of each eukaryotic cell is the cytoskeleton. Microtubules, tiny tubes consisting of a protein called tubulin, are part of this skeleton of cells. Cilia and flagella, which are antenna-like structures that protrude from most of the cells in our body, contain many micr ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by:

 

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE