Early Translational III
Stem Cell Use:
Embryonic Stem Cell
Multiple Sclerosis (MS) is a disease of the central nervous system (CNS) caused by inflammation and loss of cells that produce myelin, which normally insulates and protects nerve cells. MS is a leading cause of neurological disability among young adults in North America. Current treatments for MS include drugs such as interferons and corticosteroids that modulate the ability of immune system cells to invade the CNS. These therapies often have unsatisfactory outcomes, with continued progression of neurologic disability over time. This is most likely due to irreversible tissue injury resulting from permanent loss of myelin and nerve destruction. The limited ability of the body to repair damaged nerve tissue highlights a critically important and unmet need for MS patients. The long-term goal of our research is to develop a stem cell-based therapy that will not only halt ongoing loss of myelin but also lead to remyelination and repair of damaged nerve tissue. Our preliminary data in animal models of human MS are very promising and suggest that this goal is possible. Research efforts will concentrate on refining techniques for production and rigorous quality control of clinically-compatible transplantable cells generated from high-quality human pluripotent stem cell lines, and to verify the therapeutic activity of these cells. We will emphasize safety and development of the most therapeutically beneficial cell type for eventual use in patients with MS.
Statement of Benefit to California:
One in seven Americans lives in California, and these people make up the single largest health care market in the United States. The diseases and injuries that affect Californians affect the rest of the US and the world. Many of these diseases involve degeneration of healthy cells and tissues, including neuronal tissue in diseases such as Multiple Sclerosis (MS). The best estimates indicate that there are 400,000 people diagnosed with MS in the USA and 2.2 million worldwide. In California, there are approximately 160,000 people with MS – roughly half of MS patients in the US live in California. MS is a life-long, chronic disease diagnosed primarily in young adults who have a virtually normal life expectancy but suffer from progressive loss of motor and cognitive function. Consequently, the economic, social and medical costs associated with the disease are significant. Estimates place the annual cost of MS in the United States in the billions of dollars. The development of a stem cell therapy for treatment of MS patients will not only alleviate ongoing suffering but also allow people afflicted with this disease to return to work and contribute to the economic stabilization of California. Moreover, a stem cell-based therapy that will provide sustained recovery will reduce recurrence and the ever-growing cost burden to the California medical community.
The team has been highly productive during the first year of work on this award. A major goal of the project is to evaluate the efficacy of neural progenitor cell transplantation to promote remyelination following virus induced central nervous system damage. With intracranial infection by the virus mouse hepatitis virus (MHV), mice develop paralysis due to immune mediated destruction of cells that generate myelin. Using protocols developed in the Loring laboratory, neural precursor cells (NPC) were derived from the human embryonic stem cell line H9. Mice developing paralysis due to intracranial infection with MHV were subject to intraspinal transplantation of these NPC, resulting in significant clinical recovery beginning at 2-3 weeks following transplant. This clinical effect of NPC transplantation remained out to six months, suggesting that these NPC are effective for long-term repair following demyelination. Despite this striking recovery, these human ES cell derived NPC were rapidly rejected. Several protocols for the generation of NPC for transplantation have been characterized, with the greatest clinical impact observed for NPC cultures bearing a high level of expression of TGF beta I and TGF beta II. These findings support the hypothesis that transplanted NPC reprogram the immune system within the central nervous system (CNS), leading to the activation of endogenous NPC and other repair mechanisms. Thus, it may not be necessary to induce complete immune suppression in order to promote remyelination and CNS repair following NPC transplantation for demyelinating diseases such as multiple sclerosis.