INVESTIGATOR: Christopher Burtner, Roger Williams University
MENTOR: Matt Kaeberlein, University of Washington
THEME: Neuroscience

ABSTRACT: The prevalence of chronic disease states, such as neurodegeneration, cancer, vascular disease, and metabolic syndrome, rises precipitously in aged populations of humans. The purpose of the proposed research is to obtain a global understanding of genetic factors that extend life span in genetically tractable model systems, and to test whether experimental methods that delay mortality in model organisms also delay the onset of age-associated neurodegeneration. To identify genes involved in longevity, a genetic screen of yeast strains harboring single-gene deletions is performed using a high-throughput life span assay. Importantly, this experiment has recently been adapted into a classroom-based authentic research module appropriate for freshmen in college, and can accommodate up to 12 students in three-week blocks of time. The list of long-lived deletion strains (of which there are currently 34) acts as a starting point for thesis-driven research projects for upperclass students. ‘Hits’ from the screen will first be tested for their effect to increase the life span of the nematode C. elegans, an evolutionarily divergent eukaryote, by knocking down nematode genes that are orthologous to the yeast gene via RNA interference (RNAi). This aim provides a clearer view of the conservation of genetic factors involved in aging, which may be translatable to higher eukaryotes, such as mice. Genes involved in extending the life span of both yeast and C. elegans will then be tested for their ability to ameliorate phenotypes associated with proteotoxicity in two neurodegenerative models of C. elegans, Huntington’s disease and Alzheimer’s disease. The aggregation of a polyglutamine tract protein (implicated in Huntington’s disease) will be evaluated when longevity-associated genes are manipulated by RNAi. Using similar conditions, motility assays will be performed in C. elegans that express amyloid-beta, which is associated with Alzheimer’s. Lastly, the proposed research develops a facile and multiplexed CRISPR-based activation platform that is used to determine the effect of gene over-expression on yeast life span. This system can be programmed to specifically up-regulate the expression of a gene of interest by changing the sequence of an accessory guide RNA required for CRISPR targeting. This research will be extended to explore the feasibility of using a CRISPR-based activation method in C. elegans by feeding the guide RNA to the animals, similar to the established method of delivering RNAi in nematodes.

Relevance: Neurodegeneration leads to cognitive impairment and is a leading cause of morbidity in the elderly. The identification of genetic pathways that increase cellular and organismal longevity have the potential to delay disease progression. The characterization and interplay of these pathways is informative to the development of therapeutic approaches for neurodegeneration, such Alzheimer’s and Huntington’s disease.