Canadian Researchers Control Stem Cell Differentiation

A research group at the Hospital for Sick Children in Toronto, Canada (SickKids), has this week announced that through adding a single gene into stem cells they have managed to control the differentiation of the pluripotent cells, which can form more than 200 different tissues, into early endoderm cells that can form the basis of organs in the digestive and respiratory systems.

The findings, published in the journal 'Stem Cell', represent a step towards a greater mastery over the often unpredictable and uncontrollable cells, which are hoped one day to form the basis of a diverse range of treatments. As co-author of the study, Dr Janet Rossant, chief of research at SickKids said of stem cells in an interview with the Canadian TV Network 'CTV': "The good news is they can make every cell type. The bad news is they can make every cell type". Thus, one of the main problems hampering stem cell research and treatment development to date has been the inevitable tendency of stem cells to turn into undesired forms of cell and thus to make the production of pure batches of one form of cell incredibly difficult. This new technique brings the production of one particular kind of diversified stem cell under some form of control and results in a pure population of progenitor cells that seem to endlessly proliferate; 'a starting population' stated Dr Cheryle Seguin, the lead author of the study, 'that we can tailor to grow the tissue type or the organ we want to replace'.

Previous techniques, such as placing the stem cells in specially formulated growth hormone solutions or by seeding them into particular cultures, have failed to produce consistent results. The new technique, which involves the addition of a gene named SOX17, instead impacts upon gene transcription (the way in which the DNA of the cell is interpreted) and thus means that the stem cell will always differentiate into the same cell type. Having produced a pure population of endoderm progenitor cells it is then far easier to use chemical processes to guide the stem cells into becoming specific tissues such as liver or lung. The genetic technique appears to be so reliable that it renders external factors that would usually impact upon differentiation largely irrelevant. Thus the researchers found that even when the modified stem cells were put into conditions optimised for creating other forms of cells (for instance nerve, gut and muscle) they still became the desired endoderm cells.

In a press statement, SickKids said that controlling stem cell differentiation was 'an important leap' that 'in the future will lead us into new pathways in regenerative medicine'. The research group, which also includes academics from the Stem Cell and Cancer Research Institute at McMaster University and from Mount Sinai Hospital, is now working on applying their technique, which has so far only been used on embryonic stem cell, to 'reprogrammed' adult stem cells.