Converting adult somatic cells to pluripotent stem cells using a single virus

January 7, 2009

A Boston University School of Medicine-led research team has discovered a more efficient way to create induced Pluripotent Stem (iPS) cells, derived from mouse fibroblasts, by using a single virus vector instead of multiple viruses in the reprogramming process. The result is a powerful laboratory tool and a significant step toward the application of embryonic stem cell-like cells for clinical purposes such as the regeneration of organs damaged by inherited or degenerative diseases, including emphysema, diabetes, inflammatory bowel disease, and Alzheimer's Disease.

Their research titled "iPS Cell Generation Using a Single Lentiviral Stem Cell Cassette" appears on line in the journal Stem Cells.

Prior research studies have required multiple retroviral vectors for reprogramming -- steps that depended on four different viruses to transfer genes into the cells' DNA - essentially a separate virus for each reprogramming gene (Oct4. Klf4, Sox2 and cMyc). Upon activation these genes convert the cells from their adult, differentiated status to what amounts to an embryonic-like state.

However, the high number of genomic integrations -- 15 to 20 -- that typically occurs when multiple viruses are used for reprogramming, poses a safety risk in humans, as some of these genes (i.e. cMyc) can cause cancer. In addition, the viruses can integrate in cell locations turning on potential oncogenes.

The major milestone the six-member research team, led by Gustavo Mostoslavsky, Boston University Assistant Professor of Medicine in the Gastroenterology Section, achieved was combining the four vectors into a single "stem cell cassette" containing all four genes. The cassette (named STEMCCA) is comprised of a single multicistronic mRNA encoding the four transcription factors using a combination of 2A peptide technology and an internal ribosomal entry site (IRES).

With the STEMCCA vector, the researchers were able to generate iPS cells more efficiently -- 10 times higher than previously reported studies.

"The use of a single lentiviral vector for the derivation of iPS cells will help reduce the variability in efficiency that has been observed between different laboratories, thus enabling more consistent genetic and biochemical characterizations of iPS cells and the reprogramming process," the researchers concluded.

"We believe that the specific design of the cassette together with the fact that all four genes are expressed from the same transcript could account for the high efficiency we obtained" commented Cesar A. Sommer, first author in the paper and a postdoctoral fellow at Boston University Medical School's Gastroenterology Section.

Most importantly, several iPS clones were generated with a single viral integration, a major advance compared to the multiple integrations observed in other studies.

"Now we could move forward toward the elimination of the whole cassette using recombination technologies", noted Mostoslavsky.

Darrell N. Kotton, another co-author on the paper and an Assistant Professor at Boston University Medical School's Pulmonary Section mentioned that preliminary studies already confirmed that the STEMCCA vector works with high efficiency for the reprogramming of human cells.

Source: Boston University

Explore further: Team finds the way to generate potentially safer stem cells in the laboratory

Related Stories

Singapore scientists discover rejuvenation factors

August 13, 2015

Scientists from A*STAR's Genome Institute of Singapore (GIS) have discovered metabolic rejuvenation factors in eggs. This critical finding furthers our understanding of how cellular metabolism changes during aging, and during ...

Reprogramming the oocyte

August 26, 2015

(Phys.org)—Among other things, the egg is optimized to process the sperm genome. The cytoplasmic factors that make this possible also give the egg the ability to reprogram the nuclei from other kinds of cells if these nuclei ...

From pluripotency to totipotency

August 4, 2015

While it is already possible to obtain in vitro pluripotent cells (ie, cells capable of generating all tissues of an embryo) from any cell type, researchers from Maria-Elena Torres-Padilla's team have pushed the limits of ...

Production of iPS cells: Discovery of the fifth element

July 8, 2015

Since 2006, research has succeeded in generating, from specialised adult cells, induced pluripotent cells (iPS cells), with huge potential applications, particularly for regenerative medicine. However, the process has still ...

Recommended for you

Long-sought chiral anomaly detected in crystalline material

September 3, 2015

A study by Princeton researchers presents evidence for a long-sought phenomenon—first theorized in the 1960s and predicted to be found in crystals in 1983—called the "chiral anomaly" in a metallic compound of sodium and ...

Making nanowires from protein and DNA

September 3, 2015

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be ...

Ice sheets may be more resilient than thought

September 3, 2015

Sea level rise poses one of the biggest threats to human systems in a globally warming world, potentially causing trillions of dollars' worth of damages to flooded cities around the world. As surface temperatures rise, ice ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.