1. Production of neural cells from bone marrow stem cells.
Recent advances in stem cell technologies are expanding our ability to replace many types of tissues throughout the body. In our previous study, human neural stem cells (HNSCs), proliferated in vitro for more than a year and transplanted into 24-month-old rat brains, migrated and differentiated into both neurons and glia, and significantly improved the cognitive functions of these animals. Although HNSCs are a valuable source of transplantable material as an alternative to fetal neural tissue, the ideal replacement therapy would be the autologous transplantation of stem cells derived from the patient’s own tissues. Since we have succeeded in producing neural cells from human mesenchymal stem cells (HMeSCs), we propose the use of HMeSCs for neuroreplacement therapy. Our long-range goal is to identify the regulation of the mechanisms of stem cell lineage and to establish neuroreplacement therapy using HMeSCs isolated from individual patients. The central hypothesis of this application is that HMeSCs produce neural cells that are functionally similar to HNSC-derived cells. The objectives of this project are to find clues for the regulation of mechanisms for stem cell lineage, and to collect basic data for optimal neuroreplacement therapies using HMeSCs. The project is expected to provide fundamental data to develop clinical applications for MeSCs transplantation in patients with neurodegenerative diseases through autologus transplantation. Thus, these studies are expected to make a breakthrough in therapeutic strategies for neurodegenerative diseases. (Supported by NIH, R01 AG 23472.)

2. Physiological function of the beta-amyloid precursor protein on stem cell biology.
Although amyloid b (Ab) deposition has been a hallmark of Alzheimer’s disease (AD), the physiological function of the b-amyloid precursor protein (APP) is not yet clear. While much attention has focused on the neurotoxicity of Ab, recent studies suggest the involvement of the APP in neuroplasticity. Our preliminary studies indicate that APP functions in neural stem cell (NSC) biology. Our long-range goal is to identify whether abnormalities of APP metabolism or expression associated with AD pathology cause a deficit in adult neurogenesis. The central hypothesis of this application is that APP may play an important role in neuroplasticity by regulating the differentiation and migration of NSCs. The objective of this project is to understand the mechanisms and functions of APP in NSC biology.This project is expected to provide data that will lead to future studies characterizing NSC biology in patients with AD. Since neurodegeneration associated with glial activation is a major pathogenetic factor in AD, the proposed studies may point to novel therapeutic strategies for AD, including the augmentation of stem cell populations and modifications of APP metabolism. (Supported by Alzheimer Association IIRG-03-5577.)

3. Physiological function of reelin on stem cell biology.
Schizophrenia strikes one out of 100 young people in their prime of life. This illness not only costs society billions of dollars annually, but other costs such as the loss of individual potential, personal anguish, and family hardships are not measurable. Although many reports indicate that patients with schizophrenia express low levels of reelin, the physiological function and consequences of the downregulation of reelin in the adult brain is not yet clear. While much attention has been focused on reelin’s role in neuronal migration during corticogenesis, recent studies suggest the involvement of reelin in neuroplasticity. In addition, our preliminary studies indicate that reelin regulates neural stem cell (NSC) migration into the adult brain. Our long-range goal is to identify whether epigenetically downregulated reelin expression in schizophrenia causes a deficit in the neuroplasticity associated with NSC migration, which may be a risk factor for schizophrenia. The objective of this project is to understand the mechanisms of reelin expression and its functions in NSC migration from the molecular to the animal model level. The central hypothesis of this application is that reelin, in which the expression level is epigenetically regulated by DNA methylation of the promoter region, plays an important role in neuroplasticity by regulating the migration of NSCs. The proposed research is expected to provide fundamental data, which will lead to future studies on the characterization of NSC biology in patients with schizophrenia. Since deficits in neuroplasticity are a major contribution to schizophrenia symptomatology, these studies are expected to make a breakthrough in therapeutic strategies, which include augmentation of stem cell populations and modifications of reelin expression and its signaling pathways. (Preliminary study was published in PNAS)

4. Retinal differentiation of human stem cells
Blindness caused by retinal degeneration degrades the quality of life for millions, and with the aging of the population, contributes to the strain on the nation's health care resources. Macular degeneration, which affects 1.7 million people in the U.S., leads to the debilitating loss of vital central vision. Retinitis pigmentosa, which affects 100,000 people in the U.S., is one of the leading causes of blindness and is a disease in which the first symptoms usually show up in adolescence. While these diseases are complex and their causes are still under investigation, they result in the deterioration and loss of retinal cells. To date, there is no prevention or effective treatment for these diseases. Stem cell therapy offers the incredible possibility of treating these diseases by replacing damaged and destroyed cells. We are developing autologous cell therapy products for neuronal diseases and injuries based on its unique, patented (applied for) technology, which efficiently produces neural cells from human mesenchymal stem cells (HMeSCs). In preliminary experiments, the we have demonstrated in vivo that HMeSCs treated with the above technology after culturing with TGF-b3 migrated into the damaged retina and differentiated into opsin (photoreceptor marker)- positive cells. The objectives of this project are to evaluate production of retinal cells from HMeSCs. We propose to (1) investigate the optimal conditions for retinal differentiation of HMeSCs, (2) determine production of various kinds of retinal cells from HMeSCs, and (3) time-course assessment of HMeSCs’ migration and differentiation after transplantation. The proposed phase-1 studies are expected to provide fundamental data for the phase-2 studies, in which we will optimally treat HMeSCs and transplant these cells into retinal degeneration slow mouse and glaucoma disease models, which are animal models useful for the study of retinal degenerative diseases in humans. We will conduct functional recovery assessments (electroretinographic response) at the optimal time point after transplantation. These results will lead to the exciting possibility that our technology can be developed into a cell therapy to replace damaged retinal cells, and to restore vision utilizing cells easily obtained from the patient. This approach would avoid any of the inherent risks associated with allogeneic transplants and also would avoid the ethical and political controversies surrounding the clinical use of fetal tissue or embryonic stem cells. (Pending R41 EY015619-01)