Sunday, January 04, 2009

Stem Cell Research with Neural Injury

Regardless of personal opinion regarding stem cell research, some remarkable things are being learned about stem cells and exactly how they can help people with a wide variety of illnesses, injury and disease. Not the least of which is MS. The following is an article written by Roy Riblet, Ph.D. a member of the Multiple Sclerosis National Research Institute. If you would like more information you can contact him dierectly at There are also other papers regarding new and ongoing research on their web site
Developmental Genetics: Manipulating Stem Cells to repair neural injury
The aims of this project will lead to regenerating neural tissues from stem cells for the purpose of repairing damage to the nervous system caused by disease, such as multiple sclerosis, or injury from stroke or trauma. We seek to:
1. Identify genes that regulate the development of stem cells into all neural cell types, and identify the mechanisms controlled by these genes to reveal potential targets for therapeutic intervention.
2. Screen small molecule libraries for drug candidates that will appropriately direct stem cell differentiation towards particular mature cell types needed for tissue restoration.
Multiple sclerosis is a demyelinating disease of the central nervous system. Much attention is now focused on developing therapies to promote oligodendrocyte formation or to transplant oligodendrocytes to remyelinate damaged areas and regain function in the central nervous system. Neural Stem (NS) cells can be isolated from fetal or adult brain and can act as a source of myelinating transplants, but for greatest efficacy these cells must first be directed to the oligodendrocyte progenitor (OP) pathway. We are able to isolate and grow populations of neural stem cells and crudely direct their differentiation in culture. We will now screen and compare various effector molecules and small molecule libraries to identify compounds that will efficiently direct, for example, NS -> OP transitions. These cells can be used for remyelination transplant therapy. Alternatively, the differentiation directing compounds may be effective in inducing remyelination by endogenous NS without involving transplants.
We have in place three analytical systems to track, characterize and quantify the differentiation stages and pathways shown in the Figure. First, we have been using fluorescent antibodies and histochemical stains to identify individual cells at each developmental stage in our cultures. Next we are beginning to use Reverse Transcription-Polymerase Chain Reaction (RT-PCR) to follow induction and repression of specific critical genes involved in these differentiation steps. Lastly we are accumulating appropriate cDNA clones to construct microarrays for fluorescent hybridization analysis of the cultured cells. This will produce detailed global measurements of expression changes in a large spectrum of genes to get a complete picture of the changes in these cells as they mature, and of the effects of candidate small molecules that we identify as effective in directing differentiation.
Embryonic stem (ES) cells in culture will develop into NS at a rate which is mouse strain dependent, i.e., is genetically controlled. Therefore we will analyze several mouse strains and compare their transition rates on each step of the developmental pathways. We will correlate this data with the gene expression comparisons we generate simultaneously. This should identify the critical genes that regulate differentiation at each step and allow us to focus on these as intervention targets. In addition, a program to induce mutations in ES cells that affect the ES -> NS transition has yielded several mutants that increase this rate tenfold. We are collaborating with the research group that made these mutants to genetically map and identify these genes. We can then evaluate them as candidates for intervention and drug development.

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