RELEVANCE: Like embryonic stem cells, iPS cells can become any cell type in the body, a characteristic that could make them well-suited for therapeutic cell transplantation or for creating cell lines to study such diseases as Parkinson’s and Alzheimer’s. Inconsistencies in iPS cell quality reported in a number of recent studies have tarnished their promise, dampened enthusiasm, and fueled speculation that they may never be used therapeutically.
Tweaking the levels of factors used during the reprogramming of adult cells into induced pluriopotent stem (iPS) cells greatly affects the quality of the resulting iPS cells, according to Whitehead Institute researchers.
“This conclusion is something that I think is very surprising or unexpected—that the levels of these reprogramming factors determine the quality of the iPS cells,” says Whitehead Founding Member Rudolf Jaenisch. “We never thought they’d make a difference, but they do.”
An article describing this work is published in the December 2 issue of Cell Stem Cell.
iPS cells are made by introducing specific reprogramming genes into adult cells. These factors push the cells into a pluripotent state similar to that of embryonic stem (ES) cells. Like ES cells, iPS cells can become any cell type in the body, a characteristic that could make them well-suited for therapeutic cell transplantation or for creating cell lines to study such diseases as Parkinson’s and Alzheimer’s.
Since the creation of the first iPS cells in 2006, researchers using various reprogramming techniques have reported a broad spectrum of efficiency rates and quality of resulting iPS cells. Although researchers have shown iPS cells can fulfill all developmental tests applied to ES cells, recent reports have identified molecular differences that can influence their developmental potential and render them less-than-equivalent partners to ES cells. These inconsistencies have tarnished the promise of iPS cells, dampened enthusiasm, and fueled speculation that they may never be used therapeutically.
In one example reported last year, a lab created iPS cells using a cutting-edge technique in which a piece of DNA containing four reprogramming genes is safely integrated in the genome of adult mouse cells. In this highly publicized study, the resulting iPS cells performed poorly in tests of pluripotency and failed to produce adult mice, which is the most stringent test of pluripotency. Yet again this called into question the fidelity by which reprogramming factors could consistently generate fully reprogrammed cells equivalent to ES cells. Many in the field saw this as another nail in the coffin of iPS cells.
To Bryce Carey, first author of the Cell Stem Cell paper and a graduate student in Jaenisch’s lab at the time, this death knell seemed premature. He repeated the experiment, changing a few details, including the order in which the reprogramming factors were placed on the inserted piece of DNA. Surprisingly, such small alterations had a profound effect—more adult cells were converted to high-quality iPS cells than in the earlier, nearly identical study.
“We are trying to show that the reprogramming process is not as flawed as some have thought, and that you can isolate these fully pluripotent iPS cells that have all of the developmental potential as embryonic stem cells at a pretty high frequency,” says Carey, who is now a postdoctoral associate at Rockefeller University. “A lot of times these parameters are very difficult to control, so while the approach first described by [Shinya] Yamanaka back in 2006 is still the most reliable method for research purposes, we should be cautious in concluding there are inherent limitations. We show recovery of high-quality cells doesn’t have to be the exception.”
This work was supported by the National Science Foundation (NSF) and the National Institutes of Health (NIH).
Written by Nicole Giese* * *
* * *
“Reprogramming factor stoichiometry influences the epigenetic state and biological properties of induced pluripotent stem cells”
Cell Stem Cell, December 2, 2011
Bryce W. Carey (1,2), Styliani Markoulaki (1), Jacob Hanna (3,4), Dina A. Faddah (1,2), Yosef Buganim (1), Jongpil Kim (1), Kibibi Ganz (1), Eveline J. Steine (1), John P. Cassady (1,2), Menno P. Creyghton (1), G. Grant Welstead (1), Qing Gao (1), and Rudolf Jaenisch (1,2).1. Whitehead Institute for Biomedical Research, Cambridge, MA 02142
Nicole Giese | Newswise Science News
Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie
Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy