PM series: human naïve embryonic stem cells

In a short series, we will focus on various topics on personalized medicine in China. Third in this series: the on-going search for naive human stem cells.

At a cellular level, controlling multiplication and specialization drives growth and development. The less a cell is specialized, the more directions it can develop into. For instance, once a cell has started to develop into a brain cell, it will be complicated –though perhaps not impossible- to turn around and become a skin cell.

Finding the least specialized cell – know as the naive stem cell – may open up exciting developments in therapeutics and research. They are difficult to find, though: researchers have been looking for them in embryonic tissue, where they are mixed with a bunch of non-naive stem cells. From animal systems other than human, they have been pretty well identified and described. For numerous reasons – including obvious ethical ones – the hunt for the naive embryonic stem cell in humans has not been as productive yet.

An international consortium, from Germany, Canada, the UK and China has come one step closer in resolving the presence of naïve embryonic stem cells in human stem cells, either derived from induced stem cells, or cultured embryonic stem cells. They identified the molecular fingerprint of these cells.

The findings are promising, as the naïve stem cells can be labeled and collected for down-stream research. At the same time, the findings were unexpected: a prominent genomic structure that was associated to the naïve stem cell state appeared to be a functional trace of a virus that is only present in primate (monkey and ape) genomes. This does not fit with the expectation that maintaining a naïve state is conserved throughout, at least, vertebrate species. This study was published in nature