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6. Medical College of Georgia’s Research Institute, Robert K. Yu Dr. Yu and his team have engaged in studying the basic biology of neural stem cells in preparation for developing a cell transplantation therapy to alleviate the devastating effects of many neurodegenerative disorders, including Sanfilippo disease (Mucopolysaccharidosis III). The stem cells are derived from the inner cell mass in the blastocytes at early embryonic stages. In recent years, it has been recognized that stem cells can also be harvested from other sources, such as the umbilical cord blood. These stem cells are self-renewable and pluripotential, meaning they can be developed into different cells types, such as nerve, muscle, and bone cells, etc. Dr. Yu has induced them to differentiate into neural stem cells (NSCs) or neural progenitor cells (NPCs) that are committed to developing into brain cells. For this reason, they can be harvested and transplanted into damaged brain and to re-populate the damaged areas. The transplantation therapy therefore represents a viable therapeutic approach for repairing the injured brain tissues. Dr. Yu and his team have learned much about the properties of the NSCs/NPCs and how they become populated and interact properly with each other in test tubes. In particular, he is focusing on the role of cell surface molecules called gangliosides. These molecules are critical in determining the properties of cells and the way they become different types of nerve cells. More importantly, they play many crucial roles in determining how nerve cells interact with each other, so once the cells are transplanted into damaged brain, they can integrate with existing brain cells. This basic knowledge is essential because Dr. Yu wants to make sure the donor cells survive, migrate, and grow normally within the recipient’s brain, and he wants to avoid abnormal growth of these cells, such as tumor growth. The work is therefore highly relevant to disease treatment. In the past year, Dr. Yu and his team of investigators have successfully transplanted these cells into the brain of animal models with MPSIII to see if they can correct the storage of heparan sulfate. Preliminary studies have shown that these cells grow and integrate inside the brain after transplantation. More importantly, the recipient animals survive the transplantation surgery for a prolonged time. Animals with MPS appear to have improved biological function, as assessed by behavioral tests, which is very encouraging. In addition to the above, Dr Yu and his team have started to explore a new technique, the so-called “transposon or piggyBac” technology, for gene therapy. This is a novel way to replace missing or defective genes, such as those missing in MPSIII, into the host chromosomes. This technique is gaining momentum in the gene therapy field. Embryonic stem (ES) cells may also be amenable to ex vivo engineering by DNA modifications that render them more suitable for gene therapy. Preliminary results from Dr. Yu’s laboratory have shown that it is feasible to fortify ES cells with specific enzymes that are missing in MPSIII using this technique. He plans to transplant those engineered cells into animal brain in order to restore the biological functions in the diseased tissue. He is keenly aware that the safety and efficacy of these strategies must be fully evaluated before their use in humans with MPSIII. In addition to the above animal studies, Dr. Yu established the first state-supported Umbilical Cord Blood Stem Cell Bank in the State of Georgia three years ago. This bank promises to provide researchers with viable human stem cells, which can be harvested from cord blood. In fact, the State of Georgia has reaffirmed its commitment to cord blood stem cell collection and research by appropriating additional funds, which amounts to $1.3 million, to support this facility in 2009 alone. In 2008, Governor Sonny Perdue appointed Dr. Yu as a member of the Commission of Saving the Cure for a term of three years. The purpose of this commission is to provide guidance on clinical and basic stem cell research in Georgia. It is anticipated that there will be sufficient stem cells for the treatment of a variety of diseases, including Sanfilippo disease, in the near future. |
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