Since 2006, when Shinya Yamanaka, now the director of the Center for iPS Cell Research and Application at Kyoto University, discovered a method that could guide fully differentiated cells back to their pluripotent state, scientists have been using his recipe to produce induced pluripotent stem cells. The protocol relies on overexpressing the so-called Yamanaka factors, which are four transcription factors: Oct4, Sox2, Klf4, and cMyc (OSKM). While the technique reliably creates iPS cells, it can cause unintended effects, some of which can lead to cells to become cancerous. So researchers have worked to adjust the cocktail and understand the function of each factor.
No one had succeeded in creating iPS cells without forcing the overexpression of Oct4. It was thought that this was the most crucial factor of the four. At least until now.
If this works in adult human cells, it will be a huge advantage for the clinical applications of iPS cells.
Shinya Yamanaka, Kyoto University
Four years ago, Sergiy Velychko, a graduate student at the Max Planck Institute for Molecular Biomedicine in Hans Schlers lab, and his team were studying the role of Oct4 in creating iPS cells from mouse embryonic fibroblasts. He used vectors to introduce various mutations of the gene coding for Oct4 to the cells he was studying, along with a negative controlone that didnt deliver any Oct4. He was shocked to discover that even using his negative control, he was able to generate iPS cells.
Velychkos experiment was suggesting that it is possible to develop iPS cells with only SKM.
We just wanted to publish this observation, Velychko tells The Scientist, but he knew hed need to replicate it first because reviewers wouldnt believe it.
He and his colleagues, including Guangming Wu, a senior scientist in the lab, repeated the experiment several times, engineering vectors with different combinations of the four factors. SKMthe combination that didnt include Oct4was able to induce pluripotency in the cells with about 30 percent of the efficiency of OSKM, but the cells were of higher quality, meaning that the researchers didnt see evidence of common off-target epigenetic effects. They reported their results yesterday (November 7) in Cell Stem Cell.
Efficiency is not important. Efficiency means how many colonies do you get, explains Yossi Buganim, a stem cell researcher at the Hebrew University of Jerusalem, who was not involved in the study. If the colony is of low quality, the chances that eventually the differentiated cells will become cancerous is very high.
Finally, the team employed the ultimate test, the tetraploid complementation assay, in which iPS cells are aggregated with early embryos that otherwise would not have been able to form a fully functional embryo on their own. These embryos grew into mouse pups, meaning that the iPS cells the team created were capable of maturing into every type of cell in the animal.
Whats more is they found that the SKM iPS cells could develop into normal mouse pups 20 times more often than the OSKM iPS cells, suggesting that the pluripotency of iPS cells can be greatly improved by omitting Oct4 from the reprogramming factor cocktail.
The results will need to be verified in human cells, Buganim cautions. His team has developed methods for creating iPSCs that worked well in mouse cells only to be completely ineffective in humans.
Yamanaka himself was enthusiastic about the results, telling The Scientist in an email that his team would definitely try the method in other cell types, especially adult human blood cells and skin fibroblasts. If this works in adult human cells, it will be a huge advantage for the clinical applications of iPS cells.
S.Velychkoet al.,Excluding Oct4 from Yamanaka cocktail unleashes the developmental potential of iPSCs,Cell Stem Cell,doi:10.1016/j.stem.2019.10.002,2019.
Emma Yasinski is a Florida-based freelance reporter. Follow her on Twitter@EmmaYas24.
Read more:
Oct4, Considered Vital for Creating iPSCs, Actually Isnt Needed - The Scientist
- Politics of Stem Cell Research - May 7th, 2011 [May 7th, 2011]
- Obama Ends Funding Ban for Stem Cell Research - May 8th, 2011 [May 8th, 2011]
- Stem Cell Research: A Father's Fight - May 10th, 2011 [May 10th, 2011]
- Human Embryonic stem cell research - May 11th, 2011 [May 11th, 2011]
- Frost Over The World - Stem Cell Research and Turkey -26 Oct - May 20th, 2011 [May 20th, 2011]
- McCain Favors Embryonic Stem Cell Research - May 20th, 2011 [May 20th, 2011]
- US divided over stem cell research reversal - 09 Mar 09 - May 21st, 2011 [May 21st, 2011]
- The Politics and Promise of Stem Cell Research - May 22nd, 2011 [May 22nd, 2011]
- Inside Story - Obama to end stem cell research ban - March 9 - Part1 - May 30th, 2011 [May 30th, 2011]
- Cardiovascular Therapies: Spotlight on Stem Cell Research - Douglas Boyd - June 3rd, 2011 [June 3rd, 2011]
- The Human Embryo and Embryonic Stem Cell Biology: Spotlight on Stem Cell Research - June 3rd, 2011 [June 3rd, 2011]
- US appeals court lifts stem cell research ban - June 7th, 2011 [June 7th, 2011]
- Trailer for Mapping Stem Cell Research: Terra Incognita - June 9th, 2011 [June 9th, 2011]
- Politics: President Obama on Stem Cell Research - June 10th, 2011 [June 10th, 2011]
- Stem Cell Research Documentary - June 11th, 2011 [June 11th, 2011]
- TEDxSingapore - Susan Lim - Hype and hope of stem cell research - June 13th, 2011 [June 13th, 2011]
- Lou Gehrig's Disease (ALS): Spotlight on Stem Cell Research - Wrapup - June 14th, 2011 [June 14th, 2011]
- The Next Frontier in Stem Cell Research - June 17th, 2011 [June 17th, 2011]
- Robert Klein: Stem Cell Research - June 22nd, 2011 [June 22nd, 2011]
- Fibrocell Stem-Cell Wrinkle Smoother Wins FDA Clearance - June 23rd, 2011 [June 23rd, 2011]
- The Politics of Stem Cell Research - June 23rd, 2011 [June 23rd, 2011]
- A Dose of Reality on Alternative Stem Cell Treatments: What you don't know can hurt you - June 28th, 2011 [June 28th, 2011]
- Governor Tim Pawlenty Discusses Stem Cell Research - June 30th, 2011 [June 30th, 2011]
- The EU and stem cell research - July 5th, 2011 [July 5th, 2011]
- Parkinson's Disease: Spotlight on Stem Cell Research - Jeff Bronstein - July 6th, 2011 [July 6th, 2011]
- Cardiovascular Therapies: Spotlight on Stem Cell Research - Yung-Wei Chi - July 7th, 2011 [July 7th, 2011]
- Spotlight on Cancer Stem Cell Research - July 11th, 2011 [July 11th, 2011]
- A Stem Cell Story - July 12th, 2011 [July 12th, 2011]
- Bishop Blair bars support for Komen breast cancer group - July 13th, 2011 [July 13th, 2011]
- Stem Cell Research In Toronto - July 14th, 2011 [July 14th, 2011]
- Arthritis: Spotlight on Stem Cell Research - Introduction - July 14th, 2011 [July 14th, 2011]
- Huntington's Disease: Spotlight on Stem Cell Research 2007 - Han Keirstead - July 15th, 2011 [July 15th, 2011]
- TMconfUK2011-08 - Stem Cell Research in the UK - Prof Charles Ffrench-Constant - July 16th, 2011 [July 16th, 2011]
- UCSF opens stem cell research building - July 16th, 2011 [July 16th, 2011]
- HIV/AIDS: Spotlight on Stem Cell Research - John Zaia - July 17th, 2011 [July 17th, 2011]
- Deafness: Spotlight on Stem Cell Research - Ebenezer Yamoah - July 22nd, 2011 [July 22nd, 2011]
- Spotlight on Basic Stem Cell Research - Irv Weissman - July 25th, 2011 [July 25th, 2011]
- Diabetes: Spotlight on Stem Cell Research - Peter Butler - July 27th, 2011 [July 27th, 2011]
- Parkinson's Disease: Spotlight on Stem Cell Research - Arnold Kriegstein - July 27th, 2011 [July 27th, 2011]
- HIV/AIDS: Spotlight on Stem Cell Research - Loren Leeds - July 27th, 2011 [July 27th, 2011]
- Alzheimer's Disease: Spotlight on Stem Cell Research - Leeza Gibbons - August 2nd, 2011 [August 2nd, 2011]
- Geron's Embryonic Stem Cell Clinical Trial for Spinal Cord Injury - August 3rd, 2011 [August 3rd, 2011]
- The Skin Gun stem cell research - August 10th, 2011 [August 10th, 2011]
- Deafness: Spotlight on Stem Cell Research - Karen Doyle - August 10th, 2011 [August 10th, 2011]
- Stem Cell Research: Huntington's Disease - August 14th, 2011 [August 14th, 2011]
- Adult and Non-Embryonic Stem Cell Research Conference at Notre Dame - August 20th, 2011 [August 20th, 2011]
- Stemcell Research and Aging - Panel 1 - August 22nd, 2011 [August 22nd, 2011]
- Texans for Stem Cell Research Learn for Life: KXAN Coverage Aired August 16th, 2011 - August 24th, 2011 [August 24th, 2011]
- Stem Cell Research: Macular Degeneration - September 18th, 2011 [September 18th, 2011]
- Brilliant Minds - Stem Cell Research | Tomorrow Today - September 25th, 2011 [September 25th, 2011]
- Ethics of Stem Cell Research (1) - September 29th, 2011 [September 29th, 2011]
- Legal and Public Policy Dimensions of Stem Cell Research - September 29th, 2011 [September 29th, 2011]
- Stem cell symposium - October 2nd, 2011 [October 2nd, 2011]
- StemCONN 2011, The Latest in Stem Cell Research - October 6th, 2011 [October 6th, 2011]
- Arthritis: Spotlight on Stem Cell Research - Mark Genovese - October 7th, 2011 [October 7th, 2011]
- Judy Roberson: Patient advocates drive stem cell scientists - October 8th, 2011 [October 8th, 2011]
- Sam Harris - Stem Cells and Morality - October 8th, 2011 [October 8th, 2011]
- Stem Cell Research, Ethics and Religion - October 9th, 2011 [October 9th, 2011]
- Stem Cells: Fulfilling the Promise - 2011 CIRM Grantee Meeting - October 10th, 2011 [October 10th, 2011]
- The Skin Gun (Stem Cell research to replace burnt off skin. Done in 3 days!) - October 13th, 2011 [October 13th, 2011]
- Alzheimer's Stem Cell Research Patient Advocate Spotlight: The Faces of Neurodegenerative Disease - Video - October 18th, 2011 [October 18th, 2011]
- Life in the Balance: Perspectives on Stem Cell Research - Video - October 18th, 2011 [October 18th, 2011]
- Stem Cell Research Funding Halt - Video - October 19th, 2011 [October 19th, 2011]
- Vatican lending hand in adult stem cell research - Video - October 20th, 2011 [October 20th, 2011]
- First Spinal-Cord Surgery With Stem Cells - Video - October 21st, 2011 [October 21st, 2011]
- Michael J. Fox Embryonic Stem Cell Research - Video - October 22nd, 2011 [October 22nd, 2011]
- stem cell research - Video - October 22nd, 2011 [October 22nd, 2011]
- Gayle Atteberry - Cloning - November 5th, 2011 [November 5th, 2011]
- It Takes Nerve: UC Irvine - Sue - November 6th, 2011 [November 6th, 2011]
- Embryonic Stem Cell Research - Video - November 9th, 2011 [November 9th, 2011]
- Adult Stem Cell Research Far Ahead of Embryonic - Video - November 10th, 2011 [November 10th, 2011]
- Is stem cell research a growing concern .flv - Video - November 10th, 2011 [November 10th, 2011]
- Forbes Discusses Stem Cell Research - Video - November 14th, 2011 [November 14th, 2011]
- Stem Cell Research Presentation - Video - November 16th, 2011 [November 16th, 2011]
- Benedict XVI: No embryonic stem cell research - Video - November 28th, 2011 [November 28th, 2011]
- Batten Disease: Spotlight on Stem Cell Research - A Father's Story - Video - November 30th, 2011 [November 30th, 2011]
- CIS 111 Digital Media Project - Stem Cell Research - Video - December 13th, 2011 [December 13th, 2011]
- Regenerative Medicine and Applications of Stem Cell Research - Video - December 20th, 2011 [December 20th, 2011]
- Stem Cell Research Today: Larry Goldstein - CIRM Science Writer's Seminar - Video - December 22nd, 2011 [December 22nd, 2011]
- CIRM Bridges Award: Building California's Stem Cell Research Workforce - Video - December 22nd, 2011 [December 22nd, 2011]