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4 posts from April 2009

April 30, 2009

Stem cells going green

The recent discovery that human skin cells can be induced to become stem cells has exciting implications for studying disease and for future cell therapies. However, very few stem cells are normally found in these experiments. So, how do we overcome this problem? Within our lab at the Hospital for Sick Children we developed a method to identify human stem cells by turning them green. The method, reported in Nature Methods (April 26 online doi:10.1038/nmeth.1325; print forthcoming May 2009) quickly isolates the best stem cells so that we can then pick the best stem cell colonies that glow green under the microscope and expand them to study human disease in a petri dish.

After showing the system worked on normal mouse and human cells, it was used to isolate stem cells from both a patient and a mouse with Rett Syndrome, an autism spectrum disorder that affects girls. Rett Syndrome is caused by a mutation in the MECP2 gene and affects nerve cell maturation in the brain. Our research showed we could make nerve cells from the patient stem cells. These cells can be used in the future to investigate how nerve cells mature in patients with autism, how they signal to their neighbours and to find drugs to correct the defects.

As a further application of this technique, these mature cell types made from iPS cells could be used for transplantation therapy with some diseases or injuries, but there is a risk that any stem cells left in the culture could form tumours in the recipient. We noticed that tumours did not form if we transferred pure populations of mature cells into mice, but if green stem cells were also present then tumours were quickly established. In other words, the green reporter gene monitored the presence of tumour-forming stem cells prior to transplantation and could be used to remove them.

-- Akitsu Hotta and James Ellis, Hospital for Sick Children

April 17, 2009

International stem cell environments: a world of difference

A publication arising out of the Lay of the Land workshop, has been published by Nature Reports Stem Cells: (2009) doi:10.1038/stemcells.2009.61. See

The Lay of the Land workshop was the first key milestone for the Stem Cell Network funded project, “The Stem Cell Research Environment: Drawing the Evidence and Experience Together”, led by PI Timothy Caulfield, and co-PI’s Bartha Knoppers, Edna Einsiedel and Michael McDonald.  The Lay of the Land brought together an international group of scholars to consider the current ‘lay of the land’ of the international stem cell research environment by examining existing evidence and identifying areas requiring further exploration. 

This piece, “International stem cell environments: a world of difference” highlights the key themes arising from this focused consideration.  An extended and more comprehensive review will be published at a later date as the introduction to a special issue of Stem Cell Reviews and Reports, along with the five background papers presented at the workshop. 

-- Amy Zarzeczny, Caulfield group, University of Alberta

April 07, 2009

Janet Rossant delivers Dame Anne McLaren Memorial lecture in Oxford

The opening line of her June 12, 2007 obituary in the London Times simply states, “Dame Anne McLaren was an exceptional scientist.”  The obituary goes on to document an extraordinary career that laid a foundation for much of today’s research into genetics, stem cells and reproductive biology. However it also describes a woman who recognized the societal impact of her research, and worked hard as a member of numerous commissions and committees to contribute to the development ethical guidelines under which these new fields of science could evolve with the confidence of the public.

It is particularly apposite that Dr. Janet Rossant, head of research at the Hospital for Sick Children in Toronto, and Deputy Scientific Director of the Stem Cell Network should yesterday deliver the 2nd annual lecture given in McLaren’s honour at the UK’s National Stem Cell Network meeting in Oxford. Not only is Janet recognized as one of the world’s leading stem cell biologists, Janet has been intimately involved in the development of the ethical guidelines that govern stem cell research in Canada and abroad, first as chair of the CIHR working group that promulgated the first CIHR Guidelines for human pluripotent stem cell research, and subsequently as a member of a committee of the National Academy of Sciences in the US. Janet continues this critical role within the Stem Cell Network as co-chair of the SCN’s Policy Development Committee.

Janet’s talk yesterday focused on the different conditions and triggers by which pluripotent cells (in this case from the mouse) will turn into either embryonic stem cells (ES Cells) or trophoblast cells (TS Cells) (the first cells to differentiate in the fertilized egg that provide nutrients to the embryo and go on to form the placenta). Janet ably demonstrated that there is much to be learned about how stem cells develop from the study of TS Cells, while equally there is much to be learned about TS cells (and by extension many early developmental cues that may impact pregnancy) from the study of ES cells. Indeed this is a wider theme to which the vast majority of stem cell scientists subscribe. So much of what we have learned about stem cells has been from the comparison of different cell types. Limiting studies solely to one type (e.g. adult or cord blood) would in fact slow rather than accelerate research in those areas.

Research owes a great debt of gratitude to scientists such as Dame Anne McLaren and Dr. Janet Rossant, who think deeply about the wider societal implications of their work, and willingly invest time with the public and with policymakers to ensure appropriate research guidelines are put in place.

-- Drew Lyall, SCN Executive Director, from Oxford, UK

April 06, 2009

SCN members to present at UC Tech Transfer Forum

Leading Canadian, Californian and British stem cell investigators will be among those presenting at the UC System-Wide Technology Transfer Forum's Stem Cell and Regenerative Medicine event on April 15 in San Francisco. The focus of the event will be successes, challenges and promises in regenerative medicine as well as strategies to bridge the commercialization gap. Note that this is an invitation only event.

Researchers from the University of California will join Stem Cell Network and UK stem cell scientists in a series of panels and sessions addressed to an industry and research audeince. Attending as part of the SCN contingent are:

Profiles of research and commercialization opportunities for each of the researchers listed above will be available in the near future on a soon-to-be relaunched SCN Web site.