Ahhh the Node, my favourite part of the embryo: nice cup shape you can lie back in and get a whirly cilia massage…. OK, on with the post.
So it seems that everyone is working on stem cells now. They’re all the rage. Students come through for a rotation and ask “do you work on stem cells?”, grants with some aim that includes stem cells seem to do better than regular dev bio grants, and of course the papers….well the papers speak for themselves. But is this such a surprise and does this have any bearing on those of us who study embryonic development but haven’t cultured a stem cell other than maybe to make a knockout mouse? The answer is that it depends what you care to study, and whether you care if there is a difference between the two.
Because really stem cell biology is but an integral part of developmental biology. Stem cells, especially the non-cultured variety, are a normal part of embryonic development (or in the case of cancer stem cells, a rather unfortunate return). Isolating and culturing these stem cells is really figuring out how to freeze them in that transient state. In fact one might as well call development embryonic stem cell allocation (or something more clever). Most of you don’t need convincing, as many of the giants in stem cell biology were first giants in developmental biology (Rossant, Melton, Martin, Keller, and so on), and they simply applied the principles of embryology that they had developed to isolate the specific cell types that do their thing in the embryo. Not really simple, but you get the point.
When there were no stem cell journals, papers on stem cells or progenitors were published in development journals. Now of course we still have developmental biology journals, but a flurry of stem cell-specific journals have appeared, some bearing influential imprints, and these have done very well. I do however like the new trend, espoused recently by Development, of enthusiastically marrying back the two fields, like a happy homecoming or two good friends who parted ways years ago. It’s natural, it makes sense, and it certainly fits with what is hot right now in stem cell biology, which is helping stem cells find a path to a particular lineage and coax them become the cell type you wish to have in the dish. Sound familiar? Indeed the reverse trend is also taking place, with the stem cell journals publishing papers with a very developmental angle.
Of course the promise of therapeutics that stem cells bring distinguishes part of that field from developmental biology, but that’s the reason for it, often not the actual research that goes behind it. (Although the irony is that perhaps developmental biology’s fruits will severely diminish the therapeutic potential of stem cells: who needs the chance of a teratoma when you can just reprogram that skin cell straight into a nice neuron? )
So good friends meet again, hang out for a while, get to know each other again. As stem cell biology advances along lineage paths, and developmental biology takes a dip in the stem cell pool, we will do this with the comforting thought that we’re all doing the same thing: discovering where we come from and how we got here.