Doctor of Philosophy, Case Western Reserve University, 2011, EECS - System and Control Engineering

Systems biology has sometimes been defined as the application of systems science and engineering concepts to biological problems. This dissertation illustrates the usefulness of this approach in understanding the regulation of the mammalian cell cycle. Cell growth and division are fundamental properties of life, and the dysregulation of cell cycle control is central to the development of cancer. Understandably then, the cell cycle has historically been a popular subject for mathematical modeling efforts and we review 154 models developed over the past 80 years. Beyond mathematics however, understanding systems requires the evaluation of models against data. The work presented herein illustrates an approach for estimating the median dynamic expression profiles of cell cycle regulatory molecules from a flow cytometric snapshot of an asynchronous population, and applies this data to the modification and calibration of a computational model of mammalian cell cycle control. This contribution illustrates the value of the systems biology approach in integrating existing evidence, interpreting data, and driving new hypotheses regarding the organizing principles of biological systems. Having used single cell data to model the median trajectory of a population, we then investigate approaches to simulate cell-cell variation and reproduce the distribution of cells originally measured with flow cytometry. This comprehensive methodology also establishes an approach to studying proliferative diseases, such as hematopoietic cancers, which can be easily sampled and measured using flow cytometry. As only one static measurement is needed to define the underlying expression profile, this may provide an entry point to applying computational models and systems engineering methodologies to the treatment of individual patients.

Doctor of Philosophy, The Ohio State University, 2021, Biomedical Sciences

Few therapeutic options exist for the 15-25% of melanoma patients whose disease is driven by oncogenic NRAS. NRAS is a member of the RAS family of proto-oncogenic GTPase proteins which trigger signal transduction pathways involved in cellular motility, survival, proliferation, and metabolism. Therapeutic targeting of NRAS is a decades-old challenge, hindered by the inability to develop small molecule inhibitors specific for the mutant protein. Furthermore, oncogenic NRAS can circumvent treatments targeting post-translational RAS modifications, interacting partners, and downstream signaling pathways. Current first-line therapies for NRAS-driven melanoma are immune-based. While such drugs are effective in 40-50% of individuals, many patients suffer from high-grade adverse events and only a subset of responders experience durable remissions. With NRAS-driven melanomas being the most aggressive subtype of this disease, new and effective therapeutic options are needed. Oncogenic NRAS mutations primarily affect codons 12, 13, and 61, resulting in constitutive GTP-binding, activation, and downstream signal transduction. However, each NRAS-driven malignancy shows selection bias for a different subset of NRAS mutants. For example, NRAS-driven melanomas are enriched for genetic mutations in codon 61 (>80%) while mutations in acute myeloid leukemia primarily occur in codons 12 and 13. This mutational bias remains poorly understood, especially in melanoma where the codon 61 alterations are not directly attributed to ultraviolet light. I developed a suite of conditional, Nras knock-in mouse models (LSL-Nras Q61R, -K, -L, -H, -P, -Q; G12D and G13D, -R) to test the hypothesis that NRAS mutants commonly observed in melanoma possess functional properties required for efficient melanocyte transformation. Expression of these alleles in melanocytes revealed that the melanomagenic potential of each NRAS variant parallels the frequency of that mutation in human melanoma. Specifical (open full item for complete abstract)

Master of Sciences, Case Western Reserve University, 2021, Biology

ACF7 (actin crosslinking family protein-7) is a large actin-bundling and microtubule/actin crosslinking protein that is primarily responsible for cytoskeletal organization and integrity. Hair cells contain specialized subcellular structures to enable hearing, including the actin-rich cuticular plate and the circumferential band. ACF7 localizes to the cuticular plate and circumferential band of both mice and zebrafish. Due to known roles of ACF7 in the cytoskeleton of cell types throughout metazoans, it is plausible that ACF7 plays a vital role in the subcellular architecture of hair cell. To determine the function of ACF7 in hair cells, we used a Pax2-Cre/loxP system that removes three exons of the Macf1 actin binding domain in all descending cells of Pax2-expressing otic progenitors. Surprisingly, our data in four-week old conditional knockout mice suggests that hair cells have normal survivability, morphology, polarity, and hearing capabilities, demonstrating that the loss of ACF7 does not impact hearing in adult mice.

Master of Education (MEd), Bowling Green State University, 2010, Curriculum and Teaching

This research investigates the perceptions of biology lectures and labs according to the SETGO program students. Beliefs about the integration of biology lectures and labs, and whether biology labs cause students to use higher-order thinking skills will also be assessed in this research. There has been a push in recent years to reform traditional biology lab methods to be more inquiry-based to develop students' higher-order thinking skills. Biology lectures and labs should also have a sense of connectivity. Students should not feel like they are in two different classes when go between lab and lecture. Therefore, the students were asked how important it was for their biology lecture's content to be related to their lab's activities. Students identified that it was extremely important to have their lectures and lab linked. They also explained that their labs were not causing them to use higher-order thinking skills.

Master of Arts, The Ohio State University, 1963, Graduate School

PHD, Kent State University, 2024, College of Arts and Sciences / School of Biomedical Sciences

Many neurochemicals that affect social behavior also play a role in mediating bone development and metabolism. In primates, higher levels of neuropeptide Y and serotonin in humans and chimpanzees, compared to monkeys, are associated with decreased levels of aggression and increased social competence, respectively. Additionally, apes have higher levels of acetylcholine (ACh) and lower levels of dopamine, corresponding to internally driven and autonomous social behavior. Humans, conversely, have relatively low ACh and high dopamine, corresponding to externally driven social behavior and social conformity. ACh is specifically associated with the control of internally versus externally motivated behaviors in the striatum and is also known to promote osteoblastogenesis, bone formation, and to also inhibit bone resorption. However, the relationship between neurochemicals in the brain, bone, and behavior has, to date, remained relatively unexplored. In this dissertation, I investigate potential relationships among ACh concentrations and bone architecture by examining rats of differing levels of domestication and also among primates. I show that, in wild-caught and laboratory-raised rats, skeletal ACh concentrations, trabecular spacing, cortical bone density, and cortical area are lower in laboratory-raised rats, while bone volume is higher. Additionally, skeletal ACh may account for 40.8% of variation in trabecular spacing and 35.5% of variation in bone volume among rats. Though the difference in skeletal ACh among groups was consistent with expectations, our other findings largely contrast with currently available literature, warranting further research into the relationship between skeletal and neural ACh. I also show that, while in a highly limited primate sample, there is no relationship between skeletal and neural ACh concentrations, the methods used to explore this relationship could be used in future studies. Lastly, I show that in exploring the relationship between (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2024, Nutrition

Drug resistance in both cancer and infectious disease is a major driver of mortality across the globe. In infectious disease, the emergence of antimicrobial resistance (AMR) outpaces our ability to develop novel drugs, and within-host evolution confounds the use of previously effective drugs during the course of treatment. In cancer, while targeted therapies have improved outcomes for some, many patients continue to face metastatic, drug-resistant disease, with limited therapeutic options available. As both disease types are driven by clonal evolution, a complementary approach to treatment that leverages tools and ideas from evolutionary biology has been beneficial. However, this evolutionary-inspired therapy has thus far been limited in its consideration of drug variation in time and space within a patient (pharmacokinetics) and variable pathogen response to drug (pharmacodynamics). In this dissertation, we describe novel computational and experimental approaches that integrate pharmacokinetics and pharmacodynamics to allow for more physically realistic models of the evolution of drug resistance. We apply these approaches to gain novel insights into drug dosing regimens and drug diffusion in tissue. In Chapters 1 and 2, we briefly review integrated pharmacokinetics and pharmacodynamics in the study of drug resistance and survey the current evidence of fitness costs to drug resistance in cancer. In Chapter 3, we developed a novel, fluorescence-based time-kill protocol for estimating drug dose-dependent death rates in bacteria. In Chapter 4, we described a software package, FEArS, that allows for efficient agent-based simulation of evolution under time-varying drug concentration. In Chapter 5, we leverage both of these methods to gain insight into why some antimicrobial treatments fail using computational modeling and simulated clinical pharmacokinetics. In Chapter 6, we use spatial agent-based modeling to examine how drug diffusion in tissue can promote tumor hetero (open full item for complete abstract)

Bachelor of Science (BS), Ohio University, 2024, Environmental and Plant Biology

Caryophyllaceae flowers have a wide range of morphological appearances, particularly in regards to their stamens and petaloids. In order to determine how these structures evolved, I reviewed the phylogenetic relationships, mature morphology, and developmental pathways of flowers in the family. I concluded that in addition to an antesepalous whorl of stamens, there was likely a whorl of some ancestral structure in the alternisepalous position. This structure may have been a petal, a stamen, or a transitionary staminode, but it diversified in various lineages into the numerous forms we see today.

Doctor of Philosophy, The Ohio State University, 2024, Molecular Genetics

The formation of morphological structures of multicellular organisms relies on appropriate cell fate decisions being made. These decisions depend on highly coordinated, tightly regulated signaling network dynamics. Many cell fate decisions rely on the highly conserved EGF signaling pathway. In particular, the EGF pathway is important for the cell fate decisions of the vulval precursor cells (VPCs) in Caenorhabditis nematodes. These cells go on to form the egg-laying structure called the vulva. Reducing EGF signaling pathway activity via small molecules, like the U0126 MEK inhibitor, and mutants, like null mutants of the sur-2 Mediator complex subunit, cause species-specific fates in C. elegans and C. briggsae. In C. elegans, the P12 also uses EGF signaling activity to induce cell fates; this cell becomes part of the hindgut in later development. I hypothesized that knockdown of the EGF pathway results in the loss of cell fates in both C. elegans and C. briggsae P12 with a stronger response in C. elegans, as we see in the VPCs. I found that both U0126 treatment and sur-2 mutation resulted in fewer induced cells in both organs, with a stronger effect in C. elegans lab strains than in C. briggsae lab strains. This effect was compounded in response to combination treatment. Across multiple wild-type strains, C. elegans isolates generally had more loss of cell fates in both the VPCs and P12 compared to the C. briggsae isolates. Finally, I identified several perturbations that were insufficient to induce species-specific differences, either by causing no phenotype or by resulting in organism death. Loss of EGF pathway activity reduces the cell fates taken in both the C. elegans and C. briggsae P12 with a stronger response in C. elegans, mirroring the VPCs. In summary, we can conclude that loss of EGF pathway activity results in species-specific phenotypes of both the VPCs and P12 in C. elegans and C. briggsae; these species-specific cell fate phenotypes are similar across (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Biomedical Sciences

My interdisciplinary research integrated bioinformatics and immuno-oncology, focusing on leveraging high-dimensional biological data to understand immune cell characteristics in tumor microenvironment (TME). From the biological point of view, my focus has been on the diverse CD8+ T cell landscape of TME, especially the phenomenon of T cell exhaustion, which impairs anti-tumor immunity. My work aims to understand underlying exhaustion mechanisms and to enhance the effectiveness of immunotherapies by elucidating the heterogeneity and regulatory mechanismss of exhausted T cells using single-cell RNA-seq and spatially resolved omics data. Specifically, I validated biological hypotheses by leveraging both in-house and publicly available scRNA-seq and spatially resolved omics data. In the sex bias study, I confirmed the regulatory role of the androgen receptor in T cell exhaustion in bladder cancer. Furthermore, I also corroborated the function of the GARP-TGFβ axis in immune evasion using TCGA's bulk RNA-seq data, which indirectly promoted T cell exhaustion and undermined immunotherapy. Moving from biology to computation, I leveraged general graph representation models to learn and represent patterns of regulatory mechanisms in specific cell types and functional tissue units (FTUs) from scRNA-seq and spatially resolved omics data. I established an R package and web server, IRIS-FGM and IRIS3, to discover the regulatory pattern using scRNA-seq. Regarding spatially resolved omics data, I formulated RESEPT, a deep learning framework, to effectively characterize and visualize histological patterns and gene expression coherence in spatial domains. Furthermore, I developed SpaGFT to provide an unbiased representation method of FTU patterns. After establishing those general methods, I also fine-tuned these computational tools using specific cases and provided novel hypotheses. Refinement of IRIS3 with sex-specific scRNA-seq data led to the identification of unrecognized (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2023, Pharmacology

Mitochondria form dynamic networks and need to maintain a delicate balance between fission and fusion to satisfy the cell's energetic and metabolic requirements. Fission is necessary to ensure mitochondria are properly distributed throughout the cell and to remove damaged mitochondrial components. The dysregulation of mitochondrial dynamics resulting in either an abnormally fragmented or interconnected mitochondrial network is associated with a variety of pathologies. Mutations in dynamin-related protein 1 (Drp1), the master regulator of mitochondrial fission, have been identified in patients presenting with severe neurological defects. Patient-derived fibroblasts exhibit hyperfused mitochondria, indicating mitochondrial dysregulation. Thus, these clinically relevant mutations impair Drp1 function, but the mechanism by which these mutations disrupt mitochondrial fission was undetermined. To address this lack of knowledge, the overarching objective of this research was to elucidate the specific Drp1 functional defects that are caused by these disease-associated mutations to better understand the relationship between impaired Drp1 function and disease. Drp1 self-assembles around the outer mitochondrial membrane (OMM) and, subsequently, hydrolyzes GTP which provides the mechanical force required to cleave apart the mitochondrion. The recruitment of Drp1 to the OMM is mediated in part by lipid interactions. A mitochondria-specific lipid, cardiolipin, promotes Drp1 self-assembly, enhances its GTPase activity, and is believed to facilitate membrane constriction. Disease-associated mutations in Drp1 are predominantly located within the GTPase and middle domains, which mediate its capabilities for hydrolysis and self-assembly, respectively. We have employed an ensemble of biochemical and EM-based techniques to investigate the impact of these mutations on the self-assembly, lipid recognition, and enzymatic capabilities of Drp1. Ultimately, we have shown that even mutatio (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2023, Biological Sciences

All epithelia are characterized by keratins, which make up a type of intermediate filament (IF). In epithelial tumors, which account for the majority of clinical cancers, the loss of cytoskeletal integration is considered one of the first alterations in epithelial metaplasia. This may have something to do with the expression of keratins or rearrangement of keratin filaments. In this study, I employed shotgun proteomic analysis and bioinformatic tools to identify proteins that interact with keratin filaments and thus may contribute to the disintegration of cytoskeleton. Using four airway epithelial cell lines in culture, I confirmed they highly expressed Keratin 14 (K14) and its obligatory partners, Keratin 5 (K5) or Keratin 6A (K6A). This suggests that the predominant IF is made up of K14 paired with K5/K6A. Although samples were enriched in keratin-associated proteins by immunoprecipitation (IP) with an antibody directed against K14 and K17, additional keratins not specifically targeted were also captured. Proteomic analysis revealed a list of non-keratin proteins enriched by IP. Some were associated with actin and microtubules, 23 and 6 proteins, respectively. Most of these were not linearly related to keratin content by abundance, but the motor protein, dynein I heavy chain, showed a Pearson correlation coefficient (CC) of -0.84 with keratin. Similarly, of 54 proteins associated with focal adhesions, intercellular junctions, or membranes, only septin-9 had a CC suggesting its abundance tracked with that of keratins. Finally, I analyzed IP-specific proteins that were cytosolic or had unknown subcellular distribution. A CC of -0.91 was found for one of these proteins, namely 26S proteasome regulatory subunit 8 (Psmc5). Further investigation and validation of the dataset was done by GO Enrichment Analysis. Using a subset of proteins highly concentrated by IP, compared to controls, I found the GO functions predicted were intracellular transport, (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2023, EECS - Computer and Information Sciences

This dissertation presents a comprehensive approach to advancing proteomics and under-studied proteins in network biology, emphasizing the development of reliable algorithms, fair evaluation practices, and accessible computational tools. A key contribution of this work is the introduction of RoKAI, a novel algorithm that integrates multiple sources of functional information to infer kinase activity. By capturing coordinated changes in signaling pathways, RoKAI significantly improves kinase activity inference, facilitating the identification of dysregulated kinases in diseases. This enables deeper insights into cellular signaling networks, supporting targeted therapy development and expanding our understanding of disease mechanisms. To ensure fairness in algorithm evaluation, this research carefully examines potential biases arising from the under-representation of under-studied proteins and proposes strategies to mitigate these biases, promoting a more comprehensive evaluation and encouraging the discovery of novel findings. Additionally, this dissertation focuses on enhancing accessibility by developing user-friendly computational tools. The RoKAI web application provides a convenient and intuitive interface to perform RoKAI analysis. Moreover, RokaiXplorer web tool simplifies proteomic and phospho-proteomic data analysis for researchers without specialized expertise. It enables tasks such as normalization, statistical testing, pathway enrichment, provides interactive visualizations, while also offering researchers the ability to deploy their own data browsers, promoting the sharing of findings and fostering collaborations. Overall, this interdisciplinary research contributes to proteomics and network biology by providing robust algorithms, fair evaluation practices, and accessible tools. It lays the foundation for further advancements in the field, bringing us closer to uncovering new biomarkers and potential therapeutic targets in diseases like cancer, Alzheimer' (open full item for complete abstract)

Bachelor of Sciences, Ohio University, 2023, Biological Sciences

Globally, metastasis causes approximately 90% of mortality in cancer, making it a leading cause of death. In the United States, in both men and women, lung cancer is the second most prevalent cancer, with over 283,000 new cases estimated to be diagnosed in 2023. Both the tumor microenvironment (TME) and macropinocytosis have been shown to play a role in invasion, proliferation, and recurrence of cancers. Dr. Xiaozhuo Chen's lab at Ohio University studied the effects of the TME on cancer cells by performing RNA sequencing on A549. A549 are non-small cell human lung cancer (NSCLC) cells, which showed a consistent, significant upregulation of Stanniocalcin 1(STC1) gene expression when treated with extracellular ATP (eATP) and TGF-β. STC1 is a protein hormone involved in the regulation of the calcium phosphate balance, as well as ATP synthesis in mitochondria within the cell. Further studies showed that knock down of the STC1 gene led to reduced invasion and proliferation when compared to the untreated A549 cells. The aim of this project was to perform two main studies; one, to identify and assess macropinocytosis in a variety of cancer cell lines, and two, to investigate the effects of the STC1 gene on macropinocytosis. Using ATP concentration assays and IPA3 inhibition assays, macropinocytosis was examined in 11 cancer cell lines of varying cancer types. Macropinocytosis was confirmed with fluorescence microscopy by the colocalization of green fluorescent ATP and red fluorescent dextran. The impact of the knock-out of STC1 on macropinocytosis in A549 cells was investigated and quantified using ImageJ. The fluorescence microscopy study revealed that STC1 gene did play a role in macropinocytosis as predicted, which may be important for its effect on proliferation and invasion, the first step of metastasis.

Doctor of Philosophy, The Ohio State University, 2023, Biomedical Sciences

CD4+ T “helper” populations comprise a key subset of adaptive immune cells that are critical for orchestrating antigen-specific immune responses for both the clearance of pathogens and elimination of cancers. This population responds to insult-specific environmental signals, including those from cytokines, by differentiating into a number of functionally distinct subsets, which produce cytokines and interact with additional immune cells to effect their diverse functions. Of these, T follicular helper (TFH) cells are established coordinators of humoral immune responses, as they engage in bi-directional signaling with B cells, via both cell surface receptors and cytokine signals. Ultimately, this interaction is critical for the germinal center reaction, during which B cells are activated, proliferate, and are ultimately selected to support the generation of high-affinity B cell clones, and thus, high-affinity antibodies. This process is also required for the formation of long-lived plasma cell populations, which are a key part of both natural and vaccine-induced immunological memory. In contrast to this important role, TFH cells have also been implicated in autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, and others, for which the production of autoantibodies is a key aspect of pathogenesis. To date, the full scope of mechanisms underlying TFH cell differentiation are incompletely understood. Complicating this process, TFH cells are not comprised of a single, monolithic population, and numerous studies support the existence and function of ‘polyfunctional' TFH populations which exhibit characteristics of other CD4+ T cell subsets (recently reviewed in (1)). Thus, it will be important for TFH-focused work to identify not only shared, but also TFH-subset-specific, regulatory mechanisms. Here, I present findings regarding both cytokine- and transcription-mediated factor mechanisms by which TFH populations are regulated. First, we ide (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2022, Integrated Bioscience

Cadherins are cell-adhesion molecules that play important roles in animal development, maintenance and/or regeneration of adult animal tissues. In order to understand cadherins' functions in adult vertebrate visual structures, one must study their distribution in those structures. First, I examined expression of cadherin-6, cadherin-7, protocadherin-17 and protocadherin-19 in the visual structures of normal adult zebrafish using RNA in situ hybridization, followed by studying expression of two Kruppel-like transcription factors (klf6a and klf7), that are known markers for regenerating adult zebrafish retinas and optic nerves, in normal adult zebrafish brain, normal and regenerating adult zebrafish retinas. Then, I investigated expression of these cadherins in regenerating adult zebrafish retinas using both RNA in situ hybridization and quantitative PCR. Finally, as the first step in elucidating molecular mechanisms underlying protocadherin-17 (one of the cadherins that I studied) function in zebrafish visual system development, I used DNA microarray analysis to study gene expression of zebrafish embryos with their protocadherin-17 expression blocked by morpholino antisense oligonucleotides (these embryos are called protocadherin- 17 morphants). The major findings include: 1) cadherin-6, cadherin-7, protocadherin-17 and protocadherin-19 were differently expressed in the retina and major visual structures of normal adult zebrafish brain. 2) klf6a and klf7 showed similar expression patterns in most visual structures in the adult fish brain, and in regenerating retinas, but klf6a appeared to be a superior regeneration marker based on RNA in situ hybridization. 3) These four cadherin molecules showed distinct expression patterns in the regenerating zebrafish retinas. 4) Several genes involved in vision and/or visual development were significantly downregulated in the protocadherin-17 morphants compared to control embryos. My results suggest that (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2022, Mathematics

Biology provides examples of complex systems whose mechanisms and properties allow organisms to develop in a highly reproducible, or robust, manner. One such system is the growth and development of leaves in Arabidopsis thaliana. The leaf development system results in thin but expansive leaves with remarkable consistency. This growth results from inputs such as gene interactions and the geometry, growth, and division of individual cells. We want to better understand how the genetic and cellular information controls leaf growth. Mathematical modeling provides tools to better understand complex biological systems. In the case of leaf growth, we can represent gene interactions and cell geometry mathematically to simulate leaf growth. We begin by constructing a one-dimensional model which describes the gene interactions in a single stationary vertical column of leaf cells. This model shows how gene interactions produce proper gene expression and identifies system components which contribute to robustness. We then expand to a two-dimensional model which describes the gene interactions in a two dimensional cross section of cells which grow and divide according to physical forces and genetic information. This model predicts the presence of an additional gene and explains how gene interactions cause perpetual cell growth and regulate leaf curling. It also predicts and explains the phenomenon that increasing levels of environmental noise preferentially result in downward curling, which we verify biologically. Together, these models help us understand the process of Arabidopsis leaf development.

Doctor of Philosophy (PhD), Wright State University, 2022, Biomedical Sciences PhD

Gene expression in mammalian cells requires complex nuclear choreography, and there is increasing evidence that spatiotemporal organization of chromatin and nuclear compartments plays an important role in gene expression. In this dissertation, I examined the function of SON, a splicing factor with a known role in nuclear organization, in chromatin-mediated gene expression. SON association with a transcriptionally inactive U2OS 2-6-3 reporter gene array provided a useful model to study SON's chromatin dynamics. I demonstrated that SON associates with the inactive but not the activated array, and that SON's RNA binding domains are not necessary for that association. Second, I discovered a new role for SON in maintaining chromatin condensation. Whereas chromatin decondensation is typically correlated with transcription activation, I have demonstrated that reporter transcripts are not produced at decondensed SON-depleted U2OS 2-6-3 reporter gene loci, and that SON-depleted loci contain histone H3 that is trimethylated on lysine 9, a marker for transcriptionally silent chromatin. We found that SON depleted reporter loci are still transcriptionally activatable, and that inhibiting transcription elongation is not sufficient to condense the enlarged SON depleted reporter locus. These findings suggest that higher order chromatin structure and transcription activation are functionally distinct mechanisms of gene regulation that can be uncoupled. Finally, I investigated SON's role in genome-wide chromatin organization. SON-depleted cells are more susceptible to DNase digestion, implicating SON in the maintenance of chromatin stability globally. In conclusion, this study demonstrates a new function for the splicing factor SON in maintaining chromatin organization.

Doctor of Philosophy, Case Western Reserve University, 2021, Genetics

Interrogating how somatic stem cells interpret and transmit the intricate web of extracellular and intracellular signals that regulate cell state is foundational to biology and informs regenerative medicine approaches for treating disease. Oligodendrocyte progenitor cells (OPCs) are stem cells in the developing and adult brain that form oligodendrocytes, which are responsible for myelinating and supporting neuronal axons. Here, we elucidate transcriptional regulators of the oligodendrocyte lineage in both physiologic and pathologic contexts to identify strategies for promoting myelin regeneration in disease. Oligodendrocyte formation follows a multi-step process of OPC differentiation into immature oligodendrocytes, followed by subsequent maturation to myelinating oligodendrocytes. The transcriptional regulators of oligodendrocyte maturation remain unknown. Here, we discovered that the transcription factor Sox6 forms developmental condensates across gene bodies in immature oligodendrocytes to stabilize this intermediate state. Loss of Sox6 prevented condensate gene activation and accelerated maturation of OPCs directly to myelinating oligodendrocytes. This work offers a novel approach to regenerate myelinating oligodendrocytes in disease. This multi-step differentiation process is impaired by low oxygen (hypoxia) as seen in stroke, premature birth, and respiratory distress syndromes. Foundational to the hypoxic response is the accumulation of evolutionarily conserved transcription factors called hypoxia-inducible factors (HIFs). While HIFs are transiently protective, chronic HIF accumulation drives distinct pathological responses in numerous tissues and exerts a powerful influence over cell fate decisions in a multitude of stem cell types, including impairing oligodendrocyte formation from OPCs. In this study, we demonstrate that non-canonical, cell-type-specific targets of HIF1a are sufficient to impair the expression of Sox10, which is required for oligode (open full item for complete abstract)

Bachelor of Science (BS), Ohio University, 2021, Neuroscience

Arteriovenous malformation (AVM) is a disease where the typical connections between arteries and veins are abnormal and enlarged, so blood flows more directly from arteries to veins. These enlarged vessels have compromised integrity and are very susceptible to rupture. Though it only affects 0.01% of the population, AVM accounts for 2% of all strokes. AVM can also cause other issues such as aneurism, migraines, and seizures. Treatments for AVM are limited, in part because of a lack of understanding about how the disease occurs and progresses. This thesis uses a mouse model of AVM that manipulates an important developmental signaling pathway to produce AVM-like abnormal arteriovenous connections. Using such disease models, we can advance our understanding of AVM and of potential treatments for AVM. Astrocytes are cells in the brain that contribute to tissue homeostasis and the blood-brain barrier. When the brain sustains damage or disease, astrocytes undergo changes to react and respond to the injury. These are known as reactive astrocytes. These astrocytes can respond in a myriad of ways. There is currently very little research on astrocytes in brain AVM. Astrocytes play such a vital role in brain homeostasis and repair processes that it would be very clinically relevant to understand how AVM affects them. In this thesis, I sought to determine whether astrocytes are reactive in the mouse model of AVM by testing hypertrophy and proliferation, two characteristics of reactive astrocytes. I also assessed levels of glial fibrillary acidic protein (GFAP) through measuring microscope image area, protein expression, and transcript expression in astrocytes. I also tested for changes in other transcripts that could provide evidence in support of astrocyte reactivity. Astrocyte hypertrophy and proliferation increased in the AVM mutant, as compared to controls, suggesting that astrocytes became reactive during AVM pathogenesis. Cortical and cerebellar tissue area with GFAP-p (open full item for complete abstract)