Neurodegeneration

The long-term goal of my laboratory is to understand the cellular basis of neurodegeneration. We are testing the idea that neurodegeneration results from derangements in relatively few but strategic sub-cellular pathways. By identifying critical components of these pathways one could begin to not only understand the biology of neurodegeneration, but also embark on the design of novel therapeutic agents.

We are currently studying the autosomal dominant disorder Spinocerebellar Ataxia Type 1 (SCA1), a relentless disease that affects cerebellar Purkinje cells and brainstem neurons. This disorder is caused by a polyglutamine expansion in the involved disease protein and is thus similar to a growing number of disorders, including Huntington disease, that share this mutational mechanism. Patients with SCA1 begin to display cerebellar signs characterized by motor incoordination or ataxia in early to mid adulthood. Unfortunately there is no treatment for this disease and patients eventually succumb from the complications of brainstem dysfunction.

Current projects:

Testing the transcriptional hypothesis in SCA1 pathogenesis:
One of the earliest features of this disease is change in the gene expression signature within neurons affected in this disease. We are elucidating the pattern of gene expression changes in the vulnerable Purkinje cell population and identifying the contribution of these alterations to pathology.

Testing the role of the vascular and angiogenic factor VEGF in SCA1 pathogenesis.
One of the genes that we have already found to be down-regulated is the neurotrophic and angiogenic factor VEGF. Importantly, we have discovered that genetic or pharmacologic replenishment of VEGF mitigates SCA1 pathogenesis. These results suggest a novel therapeutic strategy for this incurable disease, and a possible cross-talk between the degenerating cerebellum and its microvasculature. We are pursuing mechanistic experiments to learn how low VEGF mediates SCA1 pathology. In addition, we are working actively towards testing the potential for VEGF as a therapy in human ataxic disorders.

Testing the role of ataxin-1 misfolding and clearance in disease pathogenesis.
Several studies suggest that ataxin-1 accumulates in neurons because of its inability to be cleared by the protein-misfolding chaperone pathway. We are testing different strategies to promote ataxin-1 clearance.

In addition to spinocerebellar ataxia, we are also studying genetic parkinsonian and dystonic syndromes.