Functional analysis of glia in tauopathy

Alzheimer's disease is the most common neurodegenerative disorder and is characterized clinically by cognitive dysfunction. Classic neuropathological features of the disease include the formation of extracellular amyloid plaques, intraneuronal deposition of abnormally phosphorylated and aggregated tau protein into neurofibrillary tangles, and gliosis. Glial pathology has generally been considered a secondary, or reactive, change. However, recent advances in understanding normal and pathological glial biology have instead suggested that glia may play an active role in neurological disorders, including Alzheimer’s disease. Here we take a genetic approach to define proteins and pathways mediating the influence of glia on Alzheimer’s-associated neurodegeneration. Taking advantage of the advanced molecular and genetic tools, short lifespan, and conserved glial biology in Drosophila we will identify glial proteins and pathways that can influence tau neurotoxicity in aging adult brains. In proof of principle studies, we have validated a novel system for studying non-cell autonomous neurodegeneration in tauopathy and show that our assay system works in the context of unbiased screening. In addition, based on the observation that many genes implicated in Alzheimer’s disease through genome wide genetic association studies (GWAS) are expressed predominantly or substantially in glial cells, we will test the effect of upregulating and downregulating these GWAS-derived gene candidates in fly glia on tau-induced neurotoxicity. To additionally connect our genetic model experiments with the authentic human disease, we will use state-of-the-art informatics tools to integrate functional genetic data with Alzheimer’s disease transcriptomics and proteomics. Since our systems analysis will be performed on a glial subtype-specific basis our studies can not only outline glial networks modulating the toxicity of tau to neurons, but also provide functional insight into newly defined glial subtypes. Our studies will develop fundamental insights into glia cell biology in health and disease and will expand the array of cellular and molecular targets relevant for therapy development in Alzheimer’s disease and related neurodegenerative disorders.