Genetic factors are primarily responsible for multiple sclerosis (MS), although environmental factors also play a role. However, cell lines with a MS genome currently are not available for research. Recent studies suggest that human embryonic stem cell (hESC) lines with MS genome could be derived by fusing hESC to fibroblasts from MS patients. Neural and immune cell types could be differentiated from these hESC cells with MS genome. These hybrids would provide a platform to study the genetic factors of MS, and to study the interactions between environmental factors and MS susceptibility which is believed to be genetic. Most importantly, they could provide MS susceptible cells with identical genome to different research laboratories for conducting research and comparing results. These hybrid hESC lines could provide target MS cells to facilitate new drug and treatment developments, pre-clinical toxicity studies. We believe they will greatly accelerate MS research while avoiding the technological and societal difficulty of generating hESC by nuclear transfer. The overall goals of this proposal are: 1) Derive hESC lines with MS genomes for MS research and treatment development. 2) Identify genetic factors related to MS susceptibility.
To achieve these goals, we propose to generate tetraploid hESC lines with MS genomes by fusing hESC lines with fibroblasts donated by MS patients and unrelated healthy individuals. Tetraploid hESCs containing normal genome could be used to factor out the tetraploid artifacts. Tetraploid hESC from a clone containing a MS genome and a clone with a normal genome would be terminally differentiated into astrocytes with our established protocols. Karyotyping and STR (short tandem repeat) genotyping would be performed to assess the stability of the tetraploid genome during neural differentiation (first year). Genetic factors related to MS would most likely cause difference in the maturation of neural progenitor. After the access of genome stability, tetraploid hESC containing MS or normal genomes along with diploid hESC would be differentiated to nestin positive neural progenitors. Gene expression profiling and network analysis would be used to investigate whether different gene regulation networks are involved in the neural differentiation of these cells. The unique gene networks in hESC with MS genome are the potential MS genetic factors. Gene expression profiling would be performed to access the difference of responding to inflammatory cytokines among these astrocytes (second year). Eventually, these cells would be used to study why remyelination fails in MS.
Statement of Benefit to California:
Approximately one of every thousand Californians suffered from multiple sclerosis (MS), which is the most common neural disorders without known cause, means of prevention, or cure. MS has a strong genetic component, but no definitive genetic factor has been identified despite intensive genetic screening at various populations. Here, we propose to derive hESC lines containing MS genomes, and study how a MS genome would alter the neural differentiation of hESC. This study could reveal biological pathways in the development of MS and MS susceptibility. These biological pathways could guide MS research into treatment, and perhaps even lead to the prevention of MS.