Researchers have made two big discoveries involving embryonic stem cells. For one, they discovered that certain tissue contains the information necessary for it to form complex structures like an organ. In this case, they found that ectoderm when exposed to hypothalamic neuroepithelia in the presence of Sonic Hedgehog Protein, would form invaginated and hollow vesicles. These vesicles are similar to pituitary precursor organ called Rathke’s pouch. This tissue even exhibited the characteristic chemical markers associated with this tissue.

Second, they found that interfering with the Notch signaling pathway could induce coricotrophs differentiation. These cells, found in the anterior pituitary, are responsible for releasing the adrenocorticotropic hormone. This tissue was highly functional, even after implantation, and highlights how manipulation of signaling pathways such as Notch can induce differentiation.

As a student heavily interested in tissue engineering, I picked this article because I find stem cells fascinating because they offer an alternative solution to the traditional methods of cell-scaffold based artificial tissue. With stem cells, one could repair or fix an organ without having to replace it. This however, is far in the future as currently we are having difficult turning embryonic stem cells into any adult cell line in tissue (which is only the first step). What is relevant, however, is that the mechanisms behind stem cell differentiation can allow for the development of better in-vitro tissue, which I plan to get involved in an undergraduate lab working in.

Source: http://www.nature.com/nature/journal/v480/n7375/full/480044a.html

Picture 1: Development of Pituitary and Hypothalamus. While this picture is only somewhat related to the article, it shows how complex the tissue system is. If we can get tissues to perform some of these functions in vitro, it would be a big leap in tissue engineering.