I went to a morning session on stem cells on day 2 of the Society for Biomolecular Science meeting in Phoenix, a meeting focused on advancements in drug discovery and screening technology. After this, it’s all epigenetics.
Stephen Haggarty, Director of the Stanley Center Department of Chemical Neurology spoke on stem cells as genetically accurate disease models. The idea here is that you can take cells from a patient (and relatives) and use the clever trick first reported by Yamanaka et al. to convert skin fibroblast cells into stem cells, called induced pluripotent stem cells, or iPS cells. What this gets you is a genetically identical population of cells to do experiments or drug screening on. Since they all share the genetic mutation or mutations that are responsible for the disease affecting the patient, they’ll give you an early indication of how the drug would affect the patient. The challenge here is getting a population of cells that actually act in the dish as they would in the patient, and Dr. Haggerty reports progress his group has made in this area.
Ever since Yamanaka’s paper came out, the promise of the technique was to create patient specific stem cells for either rejection-free transplants or drug screening, yet we’re only just starting to see cell lines become available for use in this way. There are many issues related to the technique of inducing the stemness that causes cells to behave in ways that isn’t true to the disease, and the degree to which one cell within a tissue differs from neighboring cells in the same diseased tissue varies are problems that are only just beginning to be addressed. However, using a heritable and common neurological disorder, Fragile X syndrome, in which the genes involved are known, he’s derived some patient specific cells which act like the disease cells do in the body. Using fibroblasts from the Coriell repository, a repository of cells including those from diseased individuals, they derived some iPS cell lines that accurately behave as do cells isolated from a diseased individual and therefore make a good disease model. This approach could still run into complications from the effects of the stem cell induction process, but it seems fairly promising.
Work on a more complex genetic disorder, Bipolar disorder, is ongoing.
‘Technical note: Lithium for bipolar disorder is an old therapy, but Li also inhibits GSK3beta, activating Wnt and promoting cell division and other stem cell properties, so expect some interesting hits to be found in this area.