UC Riverside researcher develops novel method to grow human embryonic stem cellsAugust 20, 2008RIVERSIDE, Calif. - The majority of researchers working with human embryonic stem cells (hESCs) - cells which produce any type of specialized adult cells in the human body - use animal-based materials for culturing the cells. But because these materials are animal-based, they could transmit viruses and other pathogens to the hESCs, making the cells unsuitable for medical use. Now, a stem-cell scientist at UC Riverside has devised a method of growing hESCs in the lab that uses no animal-derived materials - an important advance in the use of hESCs for future medical purposes. Because of their tremendous potential, hESCs are considered promising sources for future cell therapy to treat diseases such as Parkinson's disease and diabetes mellitus. Noboru Sato, an assistant professor of biochemistry, developed the new method, which is not only cleaner and easier to use than conventional methods of culturing hESCs but also results in hESCs whose pluripotency - the potential to differentiate into any of the specialized cells of the body such as neurons, cardiac muscles, and insulin-producing cells - is uncompromised. Currently in labs worldwide, many researchers grow hESCs on Matrigel-coated culture plates, Matrigel being the trade name for a gelatinous extract, taken from mouse tumor cells, that contains extracellular matrices (ECMs), made up of special proteins. The Matrigel coating provides the scaffolding to which the hESCs first attach and then grow in undifferentiated colonies before differentiating into specialized cells. "The development of animal-free coating methods for hESCs still remains a major challenge due to the complexity of ECMs and insufficient knowledge about how hESCs control cell-cell and cell-ECM interactions," explained Sato, who led the research project. His lab identified a specific signaling pathway, called Rho-Rock, which the hESCs use during colony formation and which plays an important role in physical interactions between hESCs. When the researchers blocked the pathway, they found, as expected, that the normal colony formation of hESCs was considerably impaired. They also found that the hESCs maintained their pluripotency. "Until now, it was generally assumed that the hESC colony formation was pivotal for maintaining pluripotency," Sato said. "But we show that pluripotency can be retained independent of close cell-cell contact." Prue Talbot, the director of UCR's Stem Cell Center of which Sato is a member, noted that Sato's discovery could affect the way embryonic stem cells are grown in the future. "His work is certainly an important step forward in both understanding signal transduction pathways in stem cells and in the development of an improved methodology for culturing stem cells," she said. Study results appear online in the Aug. 20 issue of the Public Library of Science (PLoS) ONE. In the study, Sato's group extensively screened various types of scaffold materials in combination with Y27632, a chemical compound that blocks the Rho-Rock pathway, and found that the Matrigel coating could be replaced with "poly-D-lysine," a chemically synthesized ECM. The major advantages of poly-D-lysine over Matrigel are that poly-D-lysine is completely animal-free, easy to handle, and its quality is consistent. "We found that the growth of the hESCs under this novel culture condition was almost identical to the growth of hESCs on Matrigel-coated culture plates, with no compromise in pluripotency," Sato said. Having started his career as a physician in Japan, Sato began researching stem cell biology as a research fellow at The Rockefeller University, NY, one of the foremost research centers in the world. He accepted a faculty position in the Department of Biochemistry at UCR in 2006. He was joined in the research project by Nicole Harb of UCR and Trevor K. Archer of the National Institute of Environmental Health Sciences (NIEHS), NC. The research was a collaboration between UCR and NIEHS, and funded by UCR start-up funds to Sato and a grant to Archer from the National Institutes of Health. "Our research goal is to understand the basic mechanisms underlying unique biological functions of pluripotent stem cells, and to translate the obtained knowledge into future medical applications," Sato said. His group is now focusing on applying his technique to the latest stem cell technology, "induced pluripotent stem (iPS) cells," which are pluripotent stem cells artificially derived from adult cells without using embryos. "Our next step is to produce new animal-free iPS cell lines," Sato said. UCR's Office of Technology Commercialization has applied for a patent on Sato's discovery and is looking for industrial partners interested in further developing it. University of California - Riverside |
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| Related Stem Cells Current Events and Stem Cells News Articles New discovery about the formation of new brain cells The generation of new nerve cells in the brain is regulated by a peptide known as C3a, which directly affects the stem cells' maturation into nerve cells and is also important for the migration of new nerve cells through the brain tissue, reveals new research from the Sahlgrenska Academy published in the journal Stem Cells. Umbilical cord blood stem cell transplant may help lung, heart disorders Two separate studies published in the current issue of Cell Transplantation (18:8), - now freely available on-line have shown that transplanted human-derived umbilical cord blood (UCB) stem cells transplanted in an animal model had positive therapeutic effects on specific lung and heart disorders the animal models. Gene mismatch influences success of bone marrow transplants A commonly inherited gene deletion can increase the likelihood of immune complications following bone marrow transplantation, an international team of researchers reports in the November 22 advance online issue of Nature Genetics. New research shows versatility of amniotic fluid stem cells For the first time, scientists have demonstrated that stem cells found in amniotic fluid meet an important test of potential to become specialized cell types, which suggests they may be useful for treating a wider array of diseases and conditions than scientists originally thought. First reconstitution of an epidermis from human embryonic stem cells Stem cell research is making great strides. This is yet again illustrated by a study carried out by the I-STEM* Institute (I-STEM/ Inserm UEVE U861/AFM), published in the Lancet on 21 November 2009. The I-STEM team, directed by Marc Peschanski has just succeeded in recreating a whole epidermis from human embryonic stem cells. Bone Implant Offers Hope for Skull Deformities A synthetic bone matrix offers hope for babies born with craniosynostosis, a condition that causes the plates in the skull to fuse too soon. Your Own Stem Cells Can Treat Heart Disease The largest national stem cell study for heart disease showed the first evidence that transplanting a potent form of adult stem cells into the heart muscle of subjects with severe angina results in less pain and an improved ability to walk. The transplant subjects also experienced fewer deaths than those who didn't receive stem cells. Is hepatic differentiation of embryonic stem cells induced by valproic acid and cytokines? Embryonic stem (ES) cells, known for their capacity to proliferate indefinitely and differentiate into almost all types of cells including hepatocytes, have raised the hope of cellular replacement therapy for liver failure. Paradoxical protein might prevent cancer One difficulty with fighting cancer cells is that they are similar in many respects to the body's stem cells. By focusing on the differences, researchers at Karolinska Institutet have found a new way of tackling colon cancer. The study is presented in the prestigious journal Cell. U of M researchers find 2 units of umbilical cord blood reduce risk of leukemia recurrence A new study from the Masonic Cancer Center, University of Minnesota shows that patients who have acute leukemia and are transplanted with two units of umbilical cord blood (UCB) have significantly reduced risk of the disease returning. More Stem Cells Current Events and Stem Cells News Articles |
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