This initiative represents the first internationally coordinated effort to provide a systematic and comparative survey of the hESC lines available from various research groups around the world
Scientists with the International Stem Cell Initiative (ISCI) have identified a set of common gene expression markers that may be used to reliably characterise diverse human embryonic stem cell (hESC) lines.
The results of the groundbreaking study are published in the July 2007 issue of Nature Biotechnology.
Stem cells offer great potential to develop new therapies for cancer, diabetes, spinal cord injury, and degenerative diseases of the nervous system, such as Parkinson's disease.
Well-characterised, stable cell lines that can be predictably reproduced are essential for successful stem cell research, yet scientists previously have not had a reliable means to understand similarities and differences among the cell lines available for study.
To address this challenge, ISCI employed technology from Applied Biosystems to carry out the first comparative study of a large and diverse collection of hESC lines from 17 laboratories in the USA, Europe, Israel, Japan, and Australia.
The team used several approaches to identify a reliable set of genetic markers to characterise hESCs, which included profiling 93 genes in 59 different cell lines.
A major finding from this first phase of the ICSI project was that all of the cell lines studied shared a number of key molecular signatures, despite different genetic constitutions and the various culture techniques to which they have been subjected.
It is expected that these newly identified molecular markers may be used to validate the potential of individual hESC lines to differentiate into other types of cells, also referred to as their pluripotency status.
The ISCI scientists used the Applied Biosystems 7900HT fast real-time PCR system and custom Applied Biosystems TaqMan Arrays to identify six key genetic markers and 14 additional genes highly correlated with a key pluripotency marker in all the cell lines tested.
Applied Biosystems worked with the ISCI researchers at the centralised analytical laboratory at the University of Sheffield in the UK, to select the assays, process the arrays and analyse the results.
"These findings are a crucial first step in ensuring that future advances in the field of stem cell research involve internationally coordinated quality standards," said Paul Gokhale of the Centre for Stem Cell Research at the University of Sheffield.
"Our collective aim is to provide openness, reliability, and the ability for scientists to confidently reproduce and extend each other's work".
As a result of this ISCI study, Applied Biosystems has developed the TaqMan Array Human Stem Cell Pluripotency Panel, which targets 96 genes for independent monitoring of hESC lines to help investigators compare cell lines derived from diverse sources.
The company said it has also created a TaqMan Array Mouse Stem Cell Pluripotency Panel comprised of mouse orthologs to the genes on the human panel.
The new TaqMan arrays, along with a complete line of TaqMan low-density array gene signature panels and more than 700,000 individual TaqMan Gene Expression Assays are available on the Applied Biosystems website.
"Stem cells have shown enormous potential for improving human health, and Applied Biosystems is fully committed to supporting our customers in their research in this emerging field," said Lars Holmkvist, president of Applied Biosystems, Europe.
"The results from the first phase of the ISCI project should provide scientists with greater confidence in the biological relevance of the data obtained from research using these stem cell lines, and ultimately lead to better disease treatment and progress in regenerative medicine".
The TaqMan Arrays used in this study are microfluidic cards that enable parallel analysis of up to eight biological samples across 12 to 384 pre-loaded TaqMan gene expression assays, without requiring liquid-handling robots or multi-channel pipettes.
To perform gene expression analysis, researchers simply add cDNA to the TaqMan arrays.
The arrays were then analysed by the Applied Biosystems 7900HT Fast Real-Time PCR System.
Real-time PCR is a laboratory method that measures changes in levels of DNA and RNA in samples.
The next phase of the ISCI work will expand on the current findings by adding additional hESCs to the study in order to further verify the team's initial results, as well as to test the effects of different culture media on hESC growth and differentiation, and on genetic changes in these cells.
A comprehensive registry of the ISCI cell lines and their molecular characteristics is now publicly available.
