Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCLA scientists find molecular differences between embryonic stem cells and reprogrammed skin cells

06.07.2009
UCLA researchers have found that embryonic stem cells and skin cells reprogrammed into embryonic-like cells have inherent molecular differences, demonstrating for the first time that the two cell types are clearly distinguishable from one another.

The data from the study suggest that embryonic stem cells and the reprogrammed cells, known as induced pluripotent stem (iPS) cells, have overlapping but still distinct gene expression signatures.

The differing signatures were evident regardless of where the cell lines were generated, the methods by which they were derived or the species from which they were isolated, said Bill Lowry, a researcher with the Broad Stem Cell Research Center and a study author.

"We need to keep in mind that iPS cells are not perfectly similar to embryonic stem cells," said Lowry, an assistant professor of molecular, cell and developmental biology. "We're not sure what this means with regard to the biology of pluripotent stem cells. At this point our analyses comprise just an observation. It could be biologically irrelevant, or it could be manifested as an advantage or a disadvantage."

The study appears in the July 2, 2009 issue of the journal Cell Stem Cell.

The iPS cells, like embryonic stem cells, have the potential to become all of the tissues in the body. However, iPS cells don't require the destruction of an embryo.

The study was a collaboration between the labs of Lowry and UCLA researcher Kathrin Plath, who were among the first scientists and the first in California to reprogram human skin cells into iPS cells. The researchers performed microarray gene expression profiles on embryonic stem cells and iPS cells to measure the expression of thousands of genes at once, creating a global picture of cellular function.

Lowry and Plath noted that, when the molecular signatures were compared, it was clear that certain genes were expressed differently in embryonic stem cells than they were in iPS cells. They then compared their data to that stored on a National Institutes of Health data base, submitted by laboratories worldwide. They analyzed that data to see if the genetic profiling conducted in other labs validated their findings, and again they found overlapping but distinct differences in gene expression, Lowry said.

"This suggested to us that there could be something biologically relevant causing the distinct differences to arise in multiple labs in different experiments," Lowry said. "That answered our first question: Would the same observation be made with cell lines created and maintained in other laboratories?"

Next, UCLA researchers wanted to confirm their findings in iPS cell lines created using the latest derivation methods. The cells from the UCLA labs were derived using an older method that used integrative viruses to insert four genes into the genome of the skin cells, including some genes known to cause cancer. They analyzed cell lines derived with newer methods that do not require integration of the reprogramming factors. Their analysis again showed different molecular signatures between iPS cells and their embryo-derived counterparts, and these signatures showed a significant degree of overlap with those generated with integrative methods.

To determine if this was a phenomenon limited to human embryonic stem cells, Lowry and Plath analyzed mouse embryonic stem cells and iPS lines derived from mouse skin cells and again validated their findings. They also analyzed iPS cell lines made from mouse blood cells with the same result

"We can't explain this, but it appears something is different about iPS cells and embryonic stem cells," Lowry said. "And the differences are there, no matter whose lab the cells come from, whether they're human or mouse cells or the method used to derive the iPS cells. Perhaps most importantly, many of these differences are shared amongst lines made in various ways."

Going forward, UCLA researchers will conduct more sophisticated analyses on the genes being expressed differently in the two cell types and try to understand what is causing that differential expression. They also plan to differentiate the iPS cells into various lineages to determine if the molecular signature is carried through to the mature cells. In their current study, Lowry and Plath did not look at differentiated cells, only the iPS and embryonic stem cells themselves.

Further study is crucial, said Mark Chin, a postdoctoral fellow and first author of the study.

"It will be important to further examine these cells lines in a careful and systematic manner, as has been done with other stem cell lines, if we are to understand the role they can play in clinical therapies and what effect the observed differences have on these cells," he said.

The stem cell center was launched in 2005 with a UCLA commitment of $20 million over five years. A $20 million gift from the Eli and Edythe Broad Foundation in 2007 resulted in the renaming of the center. With more than 150 members, the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research is committed to a multi-disciplinary, integrated collaboration of scientific, academic and medical disciplines for the purpose of understanding adult and human embryonic stem cells. The center supports innovation, excellence and the highest ethical standards focused on stem cell research with the intent of facilitating basic scientific inquiry directed towards future clinical applications to treat disease. The center is a collaboration of the David Geffen School of Medicine, UCLA's Jonsson Cancer Center, the Henry Samueli School of Engineering and Applied Science and the UCLA College of Letters and Science.

Kim Irwin | EurekAlert!
Further information:
http://www.ucla.edu
http://www.stemcell.ucla.edu

More articles from Life Sciences:

nachricht Rochester scientists discover gene controlling genetic recombination rates
23.04.2018 | University of Rochester

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>