Stem cell scientists identify key regulator controlling formation of blood-forming stem cells
September 26, 2013

Stem cell scientists have moved one step closer to producing blood-forming stem cells in a Petri dish by identifying a key regulator controlling their formation in the early embryo, shows research published online today in Cell. 
The work was reported by Dr. Gordon Keller, Director of the McEwen Centre for Regenerative Medicine, and Senior Scientist at Princess Margaret Cancer Centre, both at University Health Network. Dr. Keller is also Professor in the Department of Medical Biophysics at the University of Toronto and holds a Canada Research Chair in stem cell biology.
Using mouse models to study the process of blood cell development, Dr. Keller and his team demonstrated that the retinoic acid signalling pathway is required for formation of blood-forming stem cells. Retinoic acid is produced from vitamin A and is essential for many areas of human growth and development.   
When the researchers genetically disrupted the pathway that produces retinoic acid in mice, no blood-forming stem cells were produced. When they activated the pathway at the precise stage when stem cells develop, they observed a large increase in the number of blood-forming stem cells.  
"Understanding how different cells and tissues are made in the embryo provides important clues for producing human cell types from pluripotent stem cells in a Petri dish,” says Dr. Keller.

Pluripotent stem cells are master stem cells that are able to generate many different cell types including heart, blood, pancreas and liver. To make a specific cell type from pluripotent stem cells, one must direct them down the appropriate developmental path in the Petri dish.  
Dr. Keller adds: “Our findings have identified a critical regulator for directing pluripotent stem cells to make blood-forming stem cells, bringing us one step closer to our goal of developing a new and unlimited source of these stem cells for transplantation for the treatment of different blood cell diseases.”    
This research was funded by the Canadian Institutes of Health Research and the U.S.-based National Institutes of Health. Dr. Keller’s research is also supported by the McEwen Centre for Regenerative Medicine, The Toronto General & Western Hospital Foundation, and The Princess Margaret Cancer Foundation.
About McEwen Centre for Regenerative Medicine 
The McEwen Centre for Regenerative Medicine was founded by Rob and Cheryl McEwen in 2003 and opened its doors in 2006. The McEwen Centre for Regenerative Medicine, part of Toronto-based University Health Network, is a world leading centre for stem cell research, facilitating collaboration between renowned scientists from 5 major hospitals in Toronto, the University of Toronto and around the world. Supported by philanthropic contributions and research grants, McEwen Centre scientists strive to introduce novel regenerative therapies for debilitating and life threatening illnesses including heart disease, spinal cord injury, diabetes, diseases of the blood, liver and arthritis.
About University Health Network 
University Health Network includes Toronto General and Toronto Western Hospitals, Princess Margaret Cancer Centre, and Toronto Rehabilitation Institute. The scope of research and complexity of cases at University Health Network has made it a national and international source for discovery, education and patient care. It has the largest hospital-based research program in Canada, with major research in cardiology, transplantation, neurosciences, oncology, surgical innovation, infectious diseases, genomic medicine and rehabilitation medicine. University Health Network is a research hospital affiliated with the University of Toronto.
Media contact: Jane Finlayson, Public Affairs, (416) 946-2846 
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