The in vitro production of gametes from stem cells has elicited the interest of the professional and public alike in recent years. What if we could re-create gametogenesis in a dish to discover why it sometimes fails in our patients? What if we can make oogonia and spermatogonia in vitro, and test pollutants and new drugs in large experiments, instead of relying on imperfect animal models?
Today, Professor Jacob Hanna in an excellent master lecture reviewed the achievements made so far, and looked ahead to the (not so) long road ahead. Stem cells exist in two pluripotent state, primed and naïve, and, although both can differentiate in most of the cell types in the human body, naïve stem cells are a step ahead when it comes to gametogenesis. Problem is, naïve human stem cells are hard to come by. What we usually derive from the ICM of blastocyst stage embryos are those of the primed kind, and scientists have been trying to revert them to the naïve state for several years.
Different concoctions of growth factors and inhibitors have been used, and Professor Hanna’s lab has been at the forefront of this research. In very recent years, his group has identified the gene SOX17 as a master regulator of the naïve state, a discovery that, as he explained this morning, allows modulating human stem cells to give rise to primordial germ cells (the precursors of gametes) in vitro in the human species.
Professor Hanna answered a few questions from the audience in which he indicated that, although efforts are in place to push these in vitro obtained primordial germ cells to differentiate further to mature gametes, that objective still lies far ahead for now.
The session represented another great example of how basic research supports our knowledge of infertility knowledge, and feeds the clinical medicine of tomorrow!
Rita Vassena, Member of the Executive Committee