Polyglutamine toxicity in non-neuronal cells.

The neurodegenerative polyglutamine diseases are caused by an expansion of unstable polyglutamine repeats in various disease proteins. Although these mutant proteins are expressed ubiquitously in neuronal and non-neuronal cells, they cause selective degeneration of specific neuronal populations. Recently, increasing evidence shows that polyglutamine disease proteins also affect non-neuronal cells. However, it remains unclear how the expression of polyglutamine proteins in non-neuronal cells contributes to the course of the polyglutamine diseases. Here, we discuss recent findings about the expression of mutant polyglutamine proteins in non-neuronal cells and their influence on neurological symptoms. Understanding the contribution of non-neuronal polyglutamine proteins to disease progression will help elucidate disease mechanisms and also help in the development of new treatment options.