Parkinson’s disease (PD), the second most common neurodegenerative disorder, is characterized by Lewy bodies, pathogenic protein aggregates that include alpha-synuclein oligomers. The missense mutation p.G192R in the RAB39B gene was recently found to cause X-linked dominant PD. Loss of function mutations in RAB39B are associated with X-linked intellectual disability and autism spectrum disorder. RAB39B is a member of the human Rab GTPase family which plays a role in early autophagosome formation and is implicated in intracellular vesicular trafficking. This project investigates how defects in endolysosomal trafficking caused by the p.G192R mutation in RAB39B gene leads to parkinsonism and neurodegeneration. Because RAB39B is highly conserved, we developed a Drosophila model as human RAB39B and Drosophila RAB39 share 75% similarity in amino acid sequence, including 100% identity at p.G192 and flanking amino acids. Using CRISPR/Cas9 genome editing, we created a RAB39G196R Drosophila model that we are currently characterizing for possible neurodegenerative phenotypes. We are examining locomotor deficits and lifespan in RAB39G196R mutant flies compared to isogenic controls, as well as protein aggregation by Western blot. Complementary to the Drosophila model, we developed a human neuronal model by generating induced pluripotent stem cells (iPSCs) from peripheral blood mononuclear cells (PBMC) of an affected male and similar age unaffected male family member kindred with X-linked PD due to the p.G192R mutation. We are investigating endolysosomal trafficking defects in neurons differentiated from iPSCs using antibodies specific for early and late endosomes and lysosomes. We are also examining whether insoluble ubiquitinated protein aggregates and oligomerizes alpha-synuclein are present in RAB39BG192R neurons compared to control neurons. Understanding mechanisms underlying the pathogenesis of X-linked Parkinson’s disease will elucidate the development of PD and potential novel therapeutic targets.

Parkinson's Disease (PD) is a progressive neurodegenerative disease characterized by slowness or stiffness of movement and cognitive impairment. PD is characterized neuropathologically by Lewy Body (LB) aggregates that include lipids, proteins and oligomerized alpha-synuclein. Mutations in the gene glucosidase, beta acid 1 (GBA), are not only the most common genetic risk factor for PD but also accelerate the progression of the disease. We hypothesize that mutations in GBA may mediate faster spread of pathogenic protein aggregation from neuron to neuron. Our previous work has implicated GBA in extracellular vesicle (EV) regulation, suggesting a non-cell autonomous mechanism for GBA accelerating propagation of LBs. To test this hypothesis, we are first exploring how GBA influences EV biogenesis in neurons and astrocytes by examining endolysosomal trafficking in GBA mutated neurons and astrocytes, as well as controls, differentiated from human induced pluripotent stem cells (iPSCs). Our initial results indicate that neurons heterozygous for a GBA null mutation have impaired endolysosomal trafficking with enlarged early endosomes and lysosomes, while astrocytes heterozygous for GBA null do not have impaired early trafficking. These results suggest that GBA mutations differently affect different cell types in the brain and improve our understanding of how GBA influences the spread of LB pathology. I image the iPSC derived neurons and astrocytes using a confocal microscope, for endolysosomal markers and distributions. The goal of this work is to identify novel therapeutic targets for slowing PD progression. 

The composition of metropolitan governance has many effects on land use decisions, budget allocations, housing development, transportation planning, and racial, economic, and social equity in urban areas. However, there has been little academic inquiry into the effect of regional governance structure on transportation accessibility. This paper seeks to examine statistical linkages between regional governance fragmentation and trends toward and away from greater transportation accessibility in metropolitan areas. I perform a comparative statistical analysis of 47 of the 50 largest Metropolitan Statistical Areas, examining census data from 2002 to 2022 and transit accessibility data from the University of Minnesota Accessibility Observatory from 2014 to 2021 to examine this relationship. The causal factor I investigate is metropolitan governance fragmentation, which I capture through a Governance Fragmentation Index (GFI). The dependent variable, transportation accessibility, is captured through an Accessibility Gap Index, which categorizes transportation access through accessibility levels throughout each Metropolitan Statistical Area, utilizing data from the Accessibility Observatory from 2014 to 2021. My analysis controls for potential confounding variables, such as geographic area, population size, poverty levels, and region. I expect to find that lower levels of governance fragmentation in a Metropolitan Statistical Area will be associated with greater gains in transportation accessibility. Whether or not a significant relationship is identified, the research conducted will contribute to literature and ongoing research surrounding metropolitan governance and transportation accessibility.

When a cell undergoes stress conditions, such as oxidation or aging, an increase in protein instability can occur and prevent proper cell functions. Small Heat Shock Proteins (sHSPs) are molecular chaperones that work to maintain a healthy proteome by associating with misfolded “client” proteins to delay aggregation under such conditions. HSPB5, a human sHSP, is ubiquitously expressed throughout the body. HSPB5’s disease mutant, R120G, is a defective chaperone associated with cataracts and desmin-related myopathy. It is still unknown how this mutation is detrimental despite many years of research. My research aims to understand how this mutation retunes the electrostatic properties of HSPB5, affecting its chaperone activity. Residue R120 is part of an electrostatic network that helps create an important structural feature in the folded region of HSPB5, the alpha-crystallin domain (ACD). In the unmutated (WT) protein, the ACD surface is overall positively charged. Substitution of the positive R120 to glycine alters both ACD’s structure and electrostatics. I generated two mutants, R120K (retaining positive charge) and R120D (switching to negative charge) to investigate how R120 plays a role in ACD’s conformation. Using a negatively-charged molecule, ATP, as an “electrostatic” probe in 2D NMR, I observed differences between its binding affinity to my R120 variants. I found that only R120K ACD behaves similar to WT ACD, suggesting a possible correlation between charge potential and ACD’s interactions with ATP. Currently, I am investigating if charge potential affects chaperone activity through aggregation assays with a client protein, human γD-crystallin, found in the lens and implicated in cataracts. I predict that WT and R120K, with similar electrostatic properties, will have similar chaperone activity. R120G and R120D, prevalently in an “active” state, will have higher chaperone activity. Understanding how such mutations affect HSPB5’s conformations and chaperone activity is a step forward in understanding sHSPs’ chaperone mechanism.

Recently there has been interest in two possible sources of mass in the outer solar system. First, observations of recently discovered remote outer solar system objects have suggested the presence of a ninth planet. Different numerical simulations have suggested either a less massive (1.5-3 Earth masses) planet with a semimajor axis of 250-500 AU from the Sun (the Earth orbits at 1 AU), or a more massive (5-15 Earth masses) planet at 400-800 AU. Second, data from the New Horizons spacecraft has suggested that there may be an additional roughly circular belt of objects, similar to the Kuiper Belt, beyond 60 AU. This raises the question of whether this belt would be compatible with some or all of the proposed forms of planet 9. To answer this question, I ran a series of orbital dynamics simulations with randomly generated test particles representing the proposed second Kuiper Belt, and different masses and orbital parameters for planet 9. By looking at how planet 9 changed the orbits of the test particles over the period of the simulation, I concluded that although planet 9 would not significantly affect objects orbiting at 60-100 AU, in the most extreme cases, it would significantly broaden the distribution of orbital inclinations of objects beyond 100 AU. Astronomical deep and wide surveys conducted over the next few years have the potential to detect both planet 9, and objects beyond the Kuiper Belt. If second Kuiper Belt objects are discovered, these objects having a wider-than-expected range or orbital inclinations would point to gravitational disturbances, such as those caused by planet 9. Alternatively, if planet 9 is discovered, these simulations suggest that a second Kuiper Belt would need to be more inclined than has been so far assumed.

Small heat shock proteins (sHSP) are a family of molecular chaperones whose function is to delay the harmful aggregation of other proteins. Protein aggregation is associated with neurological disorders such as Alzheimer's disease and Parkinson's disease. In many tissues, multiple sHSPs are coexpressed and tend to assemble into hetero-oligomers. Hetero-oligomers are complexes of two or more different protein species. The extent and mechanism by which these hetero-oligomeric complexes form is yet to be fully understood. The goal of my discovery-driven research is to assess how the properties of sHSP hetero-oligomers differ from the properties of homo-oligomers. In my project, I focus on three sHSPs that are highly expressed in muscle: HSPB1, HSPB5, and HSPB6. Each of these proteins exhibit different behavior when on their own. HSPB1 and HSPB5 form a distribution of large homo-oligomers, whereas HSPB6 forms a small homo-dimer. One of the most characteristic properties of the small heat shock proteins is formation of oligomers that span different sizes. Thus I am primarily determining the sizes and composition of the sHSP hetero-oligomers. I performed a comprehensive study to characterize the sizes of the hetero-oligomers using three complementary methods: analytical size exclusion chromatography, mass photometry, and native gel electrophoresis. I have found that HSPB6 is able to readily incorporate into hetero-oligomers as the concentration of the other sHSP is increased, and that the complexes are formed in a distribution of intermediate sizes. I am currently working on assessing the ability of the hetero-oligomers to act as molecular chaperones by aggregation assays. I predict the hetero-oligomers will delay protein aggregation more efficiently than HSPB6 on its own. The findings of my project give insight into why sHSPs are coexpressed and form hetero-oligomers in cells. Understanding these hetero-oligomers sheds light into the complex pathways of sHSP function. 

Pollutant removal in soils, for example through bioremediation, has long been touted as a potential solution to anthropogenically induced climate change impacts by improving soil health. Yet, these efforts are not often implemented at large-scales, and when they are, pollutant run-off and greenhouse gas (GHG) emissions outpace existing attempts. As atmospheric GHGs continue to rise outside of the safe operating space, it becomes crucial to search for avenues that offset them. Soils have huge potential to store carbon long-term, but when soils are polluted, it impacts their carbon storage capacity. It is clear we are in dire need of sustainable solutions that remove soil pollutants, increase soil carbon storage, and promote a healthy soil community. The physiological pathways that exist in plants, bacteria, and fungi are often interlinked, and evidence shows that certain interactions can ultimately lead to the storage of carbon in soils. Therefore, we hypothesize that the delivery of synergistic bacteria, fungi, and biochar via hydrogel beads will promote plant and soil communities’ ability to increase soil nutrients for plant uptake while removing pollutants and facilitating carbon storage. Preliminary data from our study, in which we applied mixed fungal-bacterial-char hydrogel beads to polluted soils growing Sorghum bicolor or Helianthus anuus, demonstrated that our novel biotechnology has potential to decrease heavy metal concentrations and toxic compounds. Additionally, we have begun analyzing the carbon storage potential through Loss on Ignition methodology, which provides measures of soil organic and inorganic carbon. Preliminary measurements show that soils that received hydrogels with an encased fungal-microbial-char consortia also increase soil carbon. These studies will not only inform the efficacy of hydrogel-delivered biofertilizers in terms of plant growth and productivity, but will also build a foundation for future research into how to promote soil health to mitigate the negative impacts of climate change.

Orofacial cleft (OFC) is a relatively common birth defect that has major impacts on affected individuals and their families. Underlying causes of OFC include genetics and environmental influences. Genome-wide association studies (GWAS) and linkage analyses have revealed genes in which DNA variants are enriched in OFC cases relative to in unaffected individuals in the same ethnic group. Only a portion of the genetic causes have been identified. Here we focus on ARHGAP29, which was identified in several GWAS of OFC. To uncover the role of this gene in craniofacial morphogenesis, and to identify other members of its regulatory pathway, we are working on deleting a paralog of this gene, arhgap29b, in zebrafish embryos. To this end, we have designed four CRISPR guide RNAs that target specific exons in the arhgap29b gene and injected them into zebrafish embryos. We predict that such embryos will a) harbor mutations in the arhgap29b gene, which we plan to test with PCR and sequencing, and b) display abnormal morphogenesis of the face, which we plan to test by microscopy. Alternatively, we may observe a) but not b). In this event we would simultaneously disrupt the other paralog, arhgap29a. These findings will advance our understanding of genes associated with orofacial cleft, hopefully leading to improved diagnosis and underpinning the design of therapies for this disorder.

In this project, I explore the settler colonial dynamics that shape Wilderness Therapy, a for-profit carceral institution that has come under scrutiny for allegations of abuse despite their mission of curing “troubled teens” through the healing benefits of the outdoors. Specifically, I investigate the relationship of Wilderness Therapy to Indigenous land dispossession, violent cure-based medical models, and power and privilege within incarcerated communities. As someone who has been to Wilderness Therapy, I am interested in exploring the web of entanglements among carceral institutions, and how my experience and research can dismantle the carceral state and prioritize equitable reparations. My research takes the form of a novel written in a hybrid structure that braids fiction and nonfiction sections. The fiction part of my novel follows a student through her journey at Desert Destinies, a made-up Wilderness Therapy Center based on the average statistics of my research. The thesis of the nonfiction work postulates that Wilderness Therapy perpetuates slow colonial violence, meaning violence that replicates colonial structures and takes place in hidden ways over such a long period of time that it is invisibilized and naturalized. My research has taken many different forms and has been guided by various methodological approaches, including ethnographic research; close readings of archival documents, including my own journals from my time incarcerated; bibliographic research in the fields of Indigenous Studies, Settler Colonial Studies, and the Environmental Humanities; and creative writing. Through this project, I hope to imagine a decolonial future beyond the carceral state in which we address the slow violence inflicted by society on a personal and community level.

Benzalkonium Chlorides (BACs) are widely used as an antimicrobial disinfectant in a variety of food and consumer goods processing. Exposure to BACs has increased significantly due to the COVID-19 pandemic. BACs have been reported in common foods like fruits, milk, and other dairy products, raising concerns about the impact of BACs on human health via oral exposure. Recent work in our lab has reported that BACs are metabolized by cytochrome P450 (CYPs) 4Fs and 2D6 in the liver. However, there is a gap in knowledge regarding how BACs and BAC metabolites are distributed throughout the body, post-oral exposure. We hypothesize that insight into BAC disposition and distribution following an oral exposure route could lead to valuable knowledge of BAC accumulation and subsequent toxicity. In this study, we exposed male and female C57BL/6 mice to deuterated C12- and C16-BACs at 120 μg/g/day for one week via a gel food diet. We harvested liver, lung, heart, spleen, and intestinal section tissues at the end of the study, as well as fecal samples at two time points, and a singular urine time point. Through a targeted BAC and BAC metabolite quantitation analysis using liquid chromatography-mass spectrometry, we found omega-oxidation of the alkyl chain to carboxylic acid followed by beta-oxidation to be a major route of metabolism. Additionally, we found that the liver and big intestine had a higher metabolizing capacity than other tissues and the C16 BACs were preferentially metabolized compared to the C12 BACs. This work provided a deeper look into the disposition and metabolism of BACs and revealed organs that are susceptible to BAC exposure for future studies

The hallmark neuropathological finding of Parkinson’s Disease (PD) is the presence of intraneuronal protein aggregates, consisting of aggregated proteins and misfolded forms of alpha-synuclein. These intraneuronal protein aggregates, known as Lewy bodies, are implicated in many neurodegenerative diseases. Lewy pathology spread in a PD brain correlates with clinical disease progression. Glucosidase, beta, acid (GBA) gene mutations, the strongest genetic risk factor for PD, is also associated with accelerated disease progression and altered extracellular vesicles (EVs). EVs play a crucial role in intercellular communication and delivery of bioactive cargos throughout the central nervous system (CNS). I use a human neuronal cell culture model derived from induced pluripotent stem cells (iPSCs) to examine how GBA mutations alter EV composition, and investigate whether EVs truly act as a vehicle for the seeding of Lewy pathology in other cells, potentially accelerating the propagation of Lewy pathology throughout the CNS. To isolate and purify EVs from the conditioned media of neurons, I use centrifugation and size exclusion chromatography. I visualize and quantify the EV’s size and concentration using a ZetaView nanoparticle analyzer. I perform Western Blot Analysis for candidate cargo proteins within EVs, including alpha-synuclein, ubiquitinated proteins, and EV intrinsic proteins (CD-63 & CD-81). I isolate EVs from the media of GBA PD or WT control neurons expressing alpha-synuclein-GFP fusion protein and apply these EVs to GBA PD or WT neurons. I anticipate that EVs secreted by GBA versus control neurons will contain increased alpha-synuclein protein levels and that increased cell death, endolysosomal trafficking defects, and aggregation of endogenous alpha-synuclein will be associated with the uptake of GBA EVs by recipient neurons. This work will provide evidence supporting the role of GBA in influencing Lewy pathology propagation via EVs, which could elucidate a novel therapeutic mechanism that could be targeted to slow the progression of neurodegeneration.

Half of the earth's photosynthetic activity occurs in the ocean. However, marine ecosystems generally have lower rates of carbon sequestration when compared to terrestrial ones. This is an opportunity to enable large scale carbon sequestration. The waters of the open ocean are nutrient deficient and can have low primary productivity. Supplying the limiting nutrients can theoretically enable rapid growth of photosynthetic cells but this growth must be contained or it will be lost to the ocean. By preparing these missing nutrients in hydrogels with efficient photosynthetic consortia, the growth process and inputs can be contained and the biomass harvested. The Winkler Lab is using this method to develope biological systems for carbon sequestration. I am researching the efficiency of microalgae and cyanobacteria consortia in seawater with native microbes. I aim to form cultures of photosynthetic marine microbes by inoculating hydrogels containing chlorella sp. in seawater samples. The objective is to optimize squestration with naturally occurring microbial consortia. Through multiple trials I have identified a mix of microbes and macroalgae cultured from the Puget Sound that exhibits rapid biomass production. Data is collected via microscopy, imaging and by measuring chemical oxygen demand and chlorophyll content. My aim is to compare this wild microbial mix to the Winkler lab's established mixes of cyanobacteria and microalgae and determine which is more effective in fixing carbon. Expected results will demonstrate this wild culture more efficient in low nutrient environments than the lab culture. Success in this project could help refine commercializable methods to remove atmospheric carbon dioxide and fight climate change. 

The heart is one of the most mechanically active organs in the body. In a mechanism known as the “Bainbridge Reflex”, the heart rate accelerates in response to the mechanical stretch induced by the increase in venous return. The cardiac pacemaker controls heart rate, and while stretch-activated channels have been identified in cardiac tissue, their molecular identity remains unknown. We hypothesize that PIEZO channels are the molecular determinant of the stretch-dependent heart rate acceleration responsible for the Bainbridge reflex. Using quantitative polymerase chain reaction (qPCR), we assessed the presence of Piezo1 and Piezo2 transcripts in the pacemaker, atrium, and ventricle of the mouse heart. Our findings revealed that both Piezo1 and Piezo2 are present in the three regions with significantly higher expression in the pacemaker and atria. Combining immunohystochemistry, tissue clearing, and super-resolution microscopy, we analyzed the distribution of Piezo1 and Piezo2 in mouse pacemaker explants. Our results show that Piezo2 is uniformly expressed in the pacemaker and surrounding atrial tissue, whereas Piezo1 exhibits higher expression levels outside the pacemaker. These results were further confirmed at the single-cell level, with immunostaining of Piezo1 and Piezo2 in isolated pacemaker cells (HCN4+) and transitional cells (HCN4-). We observed similar expression levels of Piezo2 in both cell types and increased Piezo1 expression in transitional cells. In addition, we observed distinct localization patterns for Piezo1 and Piezo2 at the subcellular level. Piezo1 predominantly localizes to the sarcolemma, while Piezo2 exhibits a striated distribution that colocalizes alternately with both the Z- and the M- line of the sarcomere. Given this pattern, half of the Piezo2 bands colocalize with the RyR. These results set the starting point to evaluate the functional role of PIEZO channels in the cardiac pacemaker.

Adolescence is a critical stage of development, a time in which social relations are pivotal to feelings of connectedness, belongingness, and wellbeing. Amidst the rise in usage of widespread social media platforms, adolescents have begun to seek out online-only friendships (OOFs), prompting our lab to explore the prevalence and quality of these social connections. We first gathered data from adolescents (n = 5756, ages 10-18) in Peru in 2020, during the COVID-19 lockdown. In 2023, we repeated and refined our prior analyses after gathering data from adolescents in Bolivia (n = 1071) and Uruguay (n = 647). We administered a Qualtrics survey asking participants to self-report on the number and perceived quality of OOFs and IPFs (in-person friendships), using the Network of Relationships Inventory (Furman and Buhmester, 1985). I served as a Research Assistant (RA) for the interACT Lab. I reviewed the literature on online friendships, performed data cleanup, and assisted on statistical analyses of our data. Given the lack of prior research on the topic, our lab sought to explore the quality of online friendships in order to provide a foundation for future investigations. Currently, our lab is analyzing the quality of IPFs vs. OOFs on the basis of self-reported levels of support, closeness, trust, and similar-interests. 79.8% of adolescents in our sample have OOFs. In addition, preliminary findings indicate that IPFs have more negative qualities than OOFs, and that OOFs have more negative qualities than IPFs . This work is important because not only does it examine adolescent technology usage in regard to social connectivity, but it also presents findings from the Global South, which is often underrepresented in psychology research. Our findings provide an understanding of the benefits and downsides of engaging in online-only friendships for adolescents in South America, a region that is too often underrepresented in psychology research.