Stem cells: master builders, drug testers, immortal elements

During embryo development, stem cells are a fleeting presence at the beginning of tissue and organ formation. If we could rewind the human developmental clock, to around 7-9-days after the egg is fertilised, we would witness a truly remarkable event, an extraordinary time when anything is possible. This is the true starting point for human development, when a group of cells develop that that can make any type of cell in the human body. These are the ‘ultimate’ stem cells.

But stem cells are not just important for a moment in time. In adults, stem cells are constantly required to sustain and repair tissues throughout life – they are the ‘master builders’. Like their embryonic counterparts, these cells share the characteristic of immortality, but are more restricted in their ability to develop into other cells: an embryonic stem cell can make every type of cell in the body, while an adult blood stem cell can make ten different types of blood cell but no other cell type.

Both types of stem cell present fundamental and fascinating questions for biologists. Stem cells fuel the turnover and repair of blood, intestine, skin and many other tissues. But under- or over-production of their output will lead to tissue damage and disease: how is this controlled so precisely? Stem cell properties can change with age and their control systems begin to break down – what causes this important system to alter and go awry?

A deeper understanding of the remarkable biology of stem cells could in future allow the production of safe and more reproducible starting materials for a wide range of applications, including cell therapies.

In certain disorders, stem cells grown in the laboratory could be used to supply new cells to renew damaged tissues and replace missing cells. In other conditions, stem cells in the body could be activated and their repair potential boosted by administering chemical or biological therapeutic agents.

As we learn how stem cells are controlled it may become possible to correct faulty behaviour that underlies some diseases, including forms of cancer. Learning how to prevent a decline in the number and activity of stem cells may help to maintain health during ageing. In addition, human stem cells grown in the laboratory can be used to produce experimental models of diseased tissues and to test therapeutic drugs.

Cambridge University has invested in recruiting high-quality investigators in mammalian stem cell research at both senior and junior levels. The Stem Cell Institute – a partnership between the University, the Wellcome Trust and the Medical Research Council – currently has 26 mainstream stem cell laboratories comprising more than 200 research staff and PhD students.

Research scientists, technology specialists and medical doctors work side by side in the Stem Cell Institute to create an international centre of excellence in stem cell biology and medicine. Cross-disciplinary approaches are commonplace and Institute investigators collaborate widely with colleagues elsewhere in the University and in other research centres. Joint research with bioindustry is also a key opportunity. Importantly, the Institute is also committed to rigorous high level training for PhD students to provide the next generation of stem cell scientists.

Our aim now is to expand to more than 30 groups in the next 5 years, an expansion made possible due to the future construction of a dedicated new building, scheduled to open in 2018 on the Cambridge Biomedical Campus. The combination of intellectual environment and excellent specialist research facilities will keep attracting leading scientists from around the world. Stem cells will continue to be one of Cambridge’s real success stories.

Professor Austin Smith is Director, and Professor Robin Franklin is Head of Translational Science, at the Wellcome Trust-MRC Cambridge Stem Cell Institute.