The exact cellular and molecular mechanisms for the progression of amyloidogenic diseases such as Alzheimer’s and Parkinson’s disease are elusive. During amyloidogenesis, soluble protein monomers aggregate to form soluble oligomers, which further aggregate to form insoluble, êžµ-sheet rich fibrils. The Daggett lab investigates the involvement of a nonstandard secondary structure called É‘-sheet in the aggregation pathway of amyloidogenic proteins. The É‘-sheet hypothesis states that É‘-sheet is formed in the soluble oligomeric species during protein aggregation. This soluble, oligomeric form of the protein with É‘-sheet secondary structure is implicated to be the toxic species in amyloidogenesis and a driver of disease pathology. One amyloidogenic protein is É‘-synuclein, the major constituent of Lewy bodies, which are a pathological hallmark of Parkinson's disease. Preliminary data reveal the presence of É‘-sheet in Parkinson's disease patient samples, showing promise for detection of Parkinson’s disease earlier than previously possible utilizing É‘-sheet secondary structure. I am working on connecting the É‘-sheet hypothesis with the amyloidogenesis of É‘-synuclein by using synthetic É‘-synuclein to link together data from different types of experiments. Experiments I conducted include the purification of É‘-synuclein from E. coli, thioflavin T aggregation assays to measure the progression of the protein from monomer to fibril, circular dichroism spectroscopy to measure the predominant secondary structure in a peptide solution, and a soluble oligomer binding assay to detect the amount of É‘-sheet content in patient or synthetic peptide samples. The purpose of my experiments is to demonstrate that É‘-sheet is formed during the amyloidogenesis of É‘-synuclein prior to fibril formation by linking together the above experiments, supporting the idea that detection of É‘-sheet in patient samples may lead to methods of catching the progression of amyloid diseases earlier than previously possible.

As of 2021, Alzheimer’s Disease (AD) afflicts 6.2 million Americans. This number is expected to climb rapidly in the coming decades as the number of individuals at the age of increased risk rises. AD is characterized by the deposition of insoluble, β-sheet-rich amyloid plaques of the amyloid β (Aβ) peptide. However, the AD-causing toxicity of Aβ is mediated by soluble, oligomeric species of the peptide formed in the process of aggregating into plaques (amyloidogenesis). These oligomers have been shown to adopt a unique secondary structure known as “α-sheet.” The onset of AD is typically sporadic, but some cases, known as familial Alzheimer’s Disease (FAD), are inherited via mutations in Aβ. None of these mutations have been studied for their ability to adopt the pathogenic α-sheet conformation. Therefore, I am investigating the impact of the Arctic (E22G), Iowa (D23N), Flemish (A21G), and Osaka (E22Δ) mutations on the amyloidogenesis and toxicity of Aβ to explain their role in FAD. I accomplish this through a Soluble Oligomer Binding Assay (SOBA) designed in the Daggett Lab to capture and quantify α-sheet conformations. Additionally I use circular dichroism, MTT cell toxicity assays and Thioflavin-T curves to investigate the aggregation pathway of these mutants. I have found that these mutations confer unique aggregation patterns to Aβ. Many of these Aβ mutants appear to adopt a stabilized α-sheet consistent with their tie to FAD. This provides an explanation of how these mutants cause FAD and offers insight into the factors that contribute to the adoption of α-sheet structure and pathogenesis of AD.

The misfolding and consequent aggregation of amyloid peptides to form insoluble fibril plaques has long been known to be implicated in amyloid diseases such as Alzheimer's Disease (AD), Type 2 Diabetes (T2D), and Transthyretin Amyloidosis (ATTR Amyloidosis). More recently, these peptides have been shown to form intermediates of unique secondary structure called alpha-sheet. Furthermore, it has been shown that these alpha-sheet intermediates, rather than the insoluble fibrils, are the toxic conformation of amyloid peptides, causing effects such as the death of neural cells and beta-cells, in AD and T2D respectively. Using this knowledge, in this project we have characterized the aggregation and structure of the amyloid peptides such as amyloid-beta and islet amyloid polypeptide under reproduceable conditions and through a variety of techniques such as thioflavin T fluorescence assays and circular dichroism. Additionally, we have shown the ability of synthetic alpha-sheet peptides to inhibit amyloid aggregation and reduce overall fibril content. Using this idea of selective alpha-sheet binding, we have developed a soluble oligomer binding assay (SOBA) that is able to detect toxic amyloid species. These SOBA experiments have shown promising results and have been used to confirm amyloid aggregation pathways as well as detect toxic amyloid at physiologically relevant concentrations, with applications in the early diagnosis of amyloid diseases.

Implications of social media on social relationships, especially those of younger people, has been widely studied in recent years as adoption of various apps grew rapidly during the late 2010s. Within this research has been a focus on the use of social media to maintain relationships. Snapchat is one of the most popular social media platforms used among Gen-Z individuals. This study investigates how college students used Snapchat during early 2021 in the COVID-19 pandemic to keep up with their friends when more typical forms of engagement were suspended. The study targeted concepts such as relational maintenance, relational closeness, relational well-being, and comparison to face-to-face communication. The study started with four virtual focus groups where I gained firsthand accounts of Snapchat use by UW students. My advisor and I then created a survey based on responses from these focus groups and administered it online to people recruited from 17 college-centric subreddits from across the United States. Results indicated a dichotomy between members of Gen-Z in their Snapchat use, where a certain portion found Snapchat to be related to positive developments within their friend group while the other portion saw the app providing an inadequate amount of closeness and maintenance. These findings suggest that Gen-Z should not be generalized as one homogenous group, but, rather, recognized as two subsets of a generation who have differing views and preferences when it comes to the influence of their virtual communication habits on their friendships. When looking at the present state of the COVID-19 pandemic, this study would be worth conducting again to identify differences now that in-person meetings have become more common.