On the physical level, substantial improvements in the interferon-beta treated mice were noticed. "At twelve weeks of age the physical performance of the mice that received the active substance was significantly improved compared to the control group. We gave them a locotronic test, where they have to cross a kind of ladder. This test is used to check motor co-ordination when walking. We also put them through a beam-walking test, which enables us to measure their balance and limb co-ordination. The treated mice did much better in both of these tests", Dr. Sittler will say.
Further proof of the positive effects of interferon-beta came from analysis of the PML nuclear bodies, involved in many cellular processes such as transcriptional regulation and apoptosis. A subset of these nuclear bodies is responsible for regulating the degradation of accumulated misfolded proteins in the cell nucleus. The treated mice had more, and very much larger, PML bodies, and they were present in the Purkinje cells, responsible for motor co-ordination emanating from the cerebellum The researchers further found that these PML bodies were clastosomes, the specialised nuclear bodies involved in the degradation of mutant ataxin-7 and other polyglutamine-containing proteins. "This, together with the physical improvements we saw in the interferon-beta treated mice, was the proof we needed that our findings in the cell could be successfully transferred to living animals", says Dr. Sittler.
"Now that we have found that interferon-beta can slow progression of disease in SCA7 mice, we believe that, after confirmation in another mouse model, it would be merited to test its effects on humans in a clinical trial,", she will say. "Such trials are difficult in rare diseases, since a special design is needed to test a hypothesis on a small number of patients. However, there are a number of
|Contact: Mary Rice|
European Society of Human Genetics