Q&A video with Paul Episode 2: stem cell & CRISPR questions answered

This is the second in a series of videos I’m doing where I answer questions about the stem cell field. You can see the Episode 1 video here.

Today I tackle more questions on the stem cell field. If you have more stem cell questions, let me know and I’ll try to answer them next time.

One reader asked me about stem cells for stroke and about one company, Athersys, in particular, but I haven’t had time to tackle that one in such a way as to do it justice so stay tuned on that good question.

I realized after the fact that regarding stem cell epigenetics I should have said broadly that this is a process of regulation of gene expression.

Artificial embryo tech reported in Science: how big is this?

Can you make an artificial embryo?

Developmental biologist Magdalena Zernicka-Goetz has long been on the trail of this seemingly almost uncatchable quarry.

With her team’s publication in Science today they took a big step forward on this path even if some major hurdles remain. You can see her discussion of the research in the YouTube video above along with interesting comments from her graduate student, Sarah Harrison who was the first author. Congrats to both.

The paper, Harrison, et al, is entitled “Assembly of embryonic and extra-embryonic stem cells to mimic embryogenesis in vitro”. The murine embryo-like structures are referred to as ETS-embryos since they are derived from both Embryonic stem cells and Trophoblast Stem cells.

The potential applications of this artificial ETS-embryo technology moving forward are broad, but there are some limits to the current version of the method. For instance, not all germ layers are represented. New Scientist quoted Robin Lovell-Badge about these limitations:

Robin Lovell-Badge at the Francis Crick Institute in London says that the embryos lack two other types of cell layer required to develop the bodies’ organs: ectoderm, which forms skin and the central nervous system, and endoderm, which makes our internal organs.”

artificial embryos

Figure 2 Series of images showing the development of ETS-embryos over a period of 5 days. Trophoblast-derived cells are stained with a DNA marker only and ESC-derived cells stained with Oct4

The team hopes to address that with future versions.

Could one ever create ‘real” living mouse embryos this way?

From New Scientist:

“We’re not planning to make a mouse in the lab using stem cells,” says Zernicka-Goetz. But she is hopeful that adding yolk sac stem cells will allow these artificial embryos to survive long enough to study the beginnings of organs like the heart.”

Another provocative open question that Harrison calls “the elephant in the room” in the video is whether this type of technology could work with human cells to make human embryo-like structures. If that is possible, a great deal of innovative research could be catalyzed, but of course huge ethical questions would emerge along the way. Harrison highlighted differences in mouse and human embryogenesis that could also be a challenge.

Of course one can more simply make early embryos through IVF, but a new perhaps tractable system like ETS-embryos may enable more flexible studies involving use CRISPR for instance. Would it bypass ethical concerns in the human context if someone went down that path? It all depends on how one defines an embryo.

Disclosure: Cell Guidance Systems, an advertiser on this blog, has licensed the embryo technology and conducted the interview in the video, but this is not a sponsored post.