This Supplement proposal takes advantage of novel genetic model systems and bioinformatic approaches developed by two young investigators supported by the MDIBL COBRE P20 award (Comparative Biology of Tissue Repair, Regeneration and Aging; P20GM104318) and extends the impact of these approaches to solving the problems in Alzheimer?s disease (AD). Each of these studies proposes a pilot project that will allow the PI to seek competing support to pursue promising leads from the research proposed in this supplement request. COBRE Project 1 (Beck). Nuclei from AD neurons exhibit global mis-localization/degradation of nuclear lamin proteins and loss of heterochromatin marks both in human patients and animal models. Although these changes in chromatin architecture have been well characterized, the exact mechanism by which they contribute to degenerative changes in AD remains unknown. This proposal aims to determine how the disruption of nuclear chromatin architecture contributes to degenerative changes in AD. Our preliminary results demonstrate that, in normal young nuclei, only genes lacking CpG islands (CGI- genes) can reside within lamina-associated heterochromatin, when transcriptionally inactive. In this project, we will test the novel hypothesis that changes in chromatin architecture in AD cause mis-localization of CGI- genes that, in turn, triggers their uncontrolled expression in tissues/contexts where they should not be expressed. We will also examine whether CGI- gene mislocalization can be used as a diagnostic marker for AD in human clinical samples. COBRE Project 3 (Rollins). During AD, the association of Tau with the ribosome leads to its dysfunction. Such dysfunction is likely due to association of Tau with ribosomal protein 6 (RPS-6). This association coincides with the dephosphorylation of RPS-6, which is a potential mechanism by which Tau causes ribosome dysfunction and AD pathology. Using genetic models of RPS-6 phosphorylation we have generated in C.elegans, we will determine if phosphorylated RPS-6 reduces association of Tau with ribosomes. This will be accomplished by tracking the association of fluorescently tagged Tau with active ribosomes using fluorescent polysome profiling. Quantifying the association of Tau with the ribosome in RPS-6 mutants that cannot be phosphorylated or mimic constitutive phosphorylation will provide direct evidence that Tau association with the ribosome is controlled by RPS-6. Furthermore, measuring the lifespan and locomotion of the RPS-6 phospho-mutants in the presence of neuronally expressed Tau will determine whether phosphorylation of RPS-6 may alleviate symptoms of AD. Successful completion of these studies will show how nuclear structural changes leads to dysregulated gene expression in AD and support the development of new diagnostic markers of AD. This work will also clarify how Tau protein causes ribosome dysfunction in AD and support development of therapies targeting RPS-6 phosphorylation to slow the onset and progression Alzheimer?s disease.
COBRE Project 1 (Beck) Nuclei from Alzheimer?s disease (AD) neurons exhibit global mis-localization/degradation of nuclear lamin proteins and loss of heterochromatin marks both in human patients and animal models. Understanding of how these structural changes contribute to AD-related pathophysiology is critical for developing intervention delaying the onset of AD-associated degenerative changes. COBRE Project 3 (Rollins) An early event in the progression of Alzheimer?s disease is dysfunction of the ribosome. This dysfunction has been attributed to the association of pathogenic Tau with the ribosome. Detailed understanding of the molecular mechanisms by which Tau associates leads to ribosome dysfunction is critical for developing therapies that slow the onset and progression Alzheimer?s disease.
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