Of Mice and Down Syndrome
One of the most interesting conversations I had was with Katheleen Gardiner of the University of Denver. I have been aware of the incredible advances in human genomics and animal models for different diseases and conditions. One of my acquaintances here in Palo Alto, Jim White, has been funding research at Stanford and other labs on understanding Down Syndrome. If we really understood what impacts Down Syndrome has on different pathways, we could come up with therapies that would make life better for people with this condition.
Down Syndrome people have three genes from Chromosome 21, and this leads to overexpression of certain proteins that affect different processes. It's more complicated than that, but it seems clear that if we can deliver drugs that offset the effects of some of these extra genes (over 200, I think), that would mitigate some of the health and cognitive affects of Down Syndrome.
Katheleen's work is around mouse models of Down Syndrome. Her group is developing a database for Down syndrome and chromosome 21 "The Chromosome 21 gene function and pathway database" at http://chr21db.cudenver.edu. They are collecting, integrating and analyzing data on chromosome 21 genes and proteins, and their corresponding genes in model organisms.
The most exciting part of our conversation was around the impacts of estrogen and Prozac on some of the key pathways in cognitive impairment in Down Syndrome. We talked about the technical difficulties of making models in mice with all the DS genes: the more genes you add to the mouse model, the harder it is to get a mouse that will be viable (overdo it and the mice no longer can breed and sustain the line for research). Our discussion talked about adding the genes to existing mice that just focused on the pathways that estrogen and Prozac could affect, since these drugs are already approved in humans.
Finally, we discussed the difficulty of getting NIH to fund the development of new mouse lines because of the risks involved. If these mice already existed, it would be easier to get government funding for the research to see if these drugs were effective in a mouse that had more of the relevant genes.
What was really exciting to me was seeing how much promise there was in these research directions, and the need for risk capital to advance this kind of work!