Huntington’s cure in flies lays groundwork for new treatment approaches

Boosting levels of two critical proteins that normally shut down during Huntington’s disease, researchers at UW–Madison and the Cold Spring Harbor Laboratory have cured fruit flies of the genetic, neurodegenerative condition.

Forms of the same proteins—known in short form as CREB and HSP-70—exist in all cells, including those of humans.

The study results, published online today by the Proceedings of the National Academy of Sciences, were a “logical finding” because of a growing body of work in the area, says senior author Jerry Yin, a UW–Madison molecular geneticist. Scientists previously knew, for example, that hiking the activity of either CREB or HSP-70 lessened symptoms in mice or flies with Huntington’s disease.

Completely reversing a disease by targeting a combination of proteins or genetic pathways, however, reflects the growing need to embrace a broader treatment paradigm in the realm of genetic disorders, says Yin.

In working with a disorder such as Fragile X Syndrome, for example, conventional therapies might focus all their efforts on repairing the genetic pathways that cause neurons to go awry. Meanwhile, “the defective gene is not just in one type of tissue,” says Yin. “And we are not yet sensitive to detecting the defects in those other tissues.”

Rather than focusing treatment strategies on single genetic pathways, then, Yin believes a promising alternative might be to simultaneously target a cocktail of gene-induced activities – all of which are set in motion, for example, by a single faulty gene.

Yin has long worked in the area of “triplet expansion” diseases such as Huntington’s and Fragile X, in which genes go haywire due to a coding defect. His collaborators on the recent fruit fly work include, among others, lead author Kanae Iijima-Ando of the Cold Spring Harbor Laboratory and UW–Madison assistant scientist Eric Drier.

Working with the simplistic genetics of flies is certainly a long way from the complex realities of humans, Yin says, particularly for diseases that can be attributed to dozens and even hundreds of abnormal gene functions.

Yet in some cases, it might turn out that gene pathways stemming from different genes converge at some point, into one common “superhighway,” says Yin. “If you know that, you can do something in the superhighway part,” he says.

Researchers studying epilepsy, for example, have discovered that at least 20 genes have a role to play in the onset of seizures, and dozens more may be involved. Though many might argue for directing research dollars to the continued search for epilepsy genes, Yin believes funding agencies should now consider investing in the search for these “superhighways” of gene convergence.

That search might be long and tedious, he adds, but it’s most certainly worth a shot. “I think the history of scientific discovery teaches us that we can’t predict anything. So we just have to play all the cards we can possibly play.”