Biochemistry, Biophysics, and Structural Biology Commons^™

Functional Analysis Of Recurrent Non-Coding Variants In Human Melanoma, Paula Maria Godoy

Arts & Sciences Electronic Theses and Dissertations

Worldwide incidence rates of cutaneous melanoma are increasing, and while survival rates for early stages of melanoma are high, rates drop precipitously for metastatic melanomas or those that are unable to be targeted by currently available treatments. As melanomas have a propensity to quickly metastasize, understanding the contributions of melanoma initiation remains critical for early intervention. Onset of melanoma is characterized most by mutations that stimulate mitogen-activated protein kinase (MAPK) signaling, disrupt DNA damage checkpoints, and trigger mechanisms to bypass senescence through elongation of telomeres. Additionally, in zebrafish melanoma models, the earliest cluster of melanoma-initiating cells activate expression of a …

Defining The Role Of Rare Genetic Variants That Drive Risk And Pathogenesis Of Alzheimer’S Disease, Matthew James Rosene

Arts & Sciences Electronic Theses and Dissertations

Alzheimer’s disease (AD) is the leading cause of dementia and is pathologically defined by the aggregation of extracellular amyloid plaques and intracellular neurofibrillary tangles. Rare heritable mutations within the genes for amyloid precursor protein (APP) and presenilin 1 (PSEN1), and presenilin 2 (PSEN2) cause early onset AD and account for approximately 1% of AD cases. While the majority of AD cases are late-onset (LOAD), which is defined by a markedly more complex genetic architecture that is comprised of many genetic risk factors that influence AD through multiple cellular pathways. The advent of deep sequencing analyses have allowed for the identification …

Slo2.1 Channels: A New Molecular Mechanism To Regulate Uterine Excitability, Juan Jose Ferreira

Arts & Sciences Electronic Theses and Dissertations

At the end of pregnancy, the uterus transitions from a non-contractile state to a highly contractile state. Two processes primarily drive this transition. First, from the 28th week of pregnancy until labor, the resting membrane potential of uterine (myometrial) smooth muscle cells (MSMCs) gradually becomes more positive (depolarizes) (Parkington et al. 1999). Second, at the end of pregnancy, MSMCs express more oxytocin receptors and become more sensitive to oxytocin (Kimura et al. 1996). However, the detailed mechanisms by which these processes occur have not been determined. My central hypothesis was that the Na+-activated K+ channel SLO2.1 plays a key role …

Mechanisms Of Natural Killer Cell Anti-Tumor Function And Homeostasis, Julia Alexandra Wagner

Arts & Sciences Electronic Theses and Dissertations

Natural killer (NK) cells are innate lymphoid cells (ILCs) that mediate anti-tumor and anti-viral immune responses. They do so via two primary effector functions: cytokine production and direct cytotoxicity. Unlike adaptive T and B lymphocytes, NK cells do not rearrange their DNA to express a predominant antigen-specific receptor, and instead express a variety of stochastically-expressed, germline DNA-encoded activating and inhibitory receptors whose signals integrate to govern their functional responses. What results is a diverse repertoire of NK cells capable of recognizing a variety of malignantly-transformed or virally-infected cells. Studies from several groups have established the anti-tumor potential of NK cells, …

Potentiation Of Tmem16a Currents By Clca1 In Cystic Fibrosis Airway, Kayla Berry

Arts & Sciences Electronic Theses and Dissertations

In the airway, proper activity of the anion channel cystic fibrosis transmembrane conductance regulator (CFTR) contributes to innate immune defense by maintaining a hydratedand alkaline mucus layer through the conductance of chloride and bicarbonate ions. This allows potentially pathogenic microorganisms to be trapped, quickly killed, and cleared via mucociliary clearance, thus preventing microbial colonization of the lungs. In cystic fibrosis (CF), this activity is impaired, resulting in repeated pulmonary infections that damage the lung and, if severe and prolonged, may lead to premature death without lung transplantation. Available therapies remain focused on targeted rescue of the CFTR mutation. However, given …

Etv2/Myct1 Axis In The Regulation Of Tumor Angiogenesis And Anti-Tumor Immunity, Ashraf Ul Kabir

Arts & Sciences Electronic Theses and Dissertations

Angiogenesis is a critical determinant of neoplastic growth and metastatic spread. As such, anti-angiogenic approaches have long been tried to throttle down tumor progression. However, current anti-angiogenic treatments so far have produced modest clinical benefits. Further in-depth research has provided rationales behind these disappointing and apparent perplexing clinical outcomes. It is now established that VEGF (vascular endothelial growth factor) and other prominent current angiogenic targets are neither specific to the vascular system nor the pathological conditions explaining the sub-optimal angiogenic control following the existing treatments. This suggests that anti-angiogenesis could still be a viable strategy for cancer patients should there …

Homeostatic T Cell Receptor Interactions With Self-Peptide Tune Cd4+ T Cell Function, Juliet Marie Bartleson

Arts & Sciences Electronic Theses and Dissertations

Homeostatic T Cell Receptor Interactions with Self-Peptide Tune CD4+ T Cell Function

by

Juliet Marie Bartleson

Doctor of Philosophy in Biology and Biomedical Sciences

Immunology

Washington University in St. Louis, 2021

Professor Paul M. Allen, Chair

Mature CD4+ T cells circulate throughout peripheral secondary lymphoid organs using their T cell receptor (TCR) to surveil peptide presented on major histocompatibility complex class II molecules (pMHC) in search of cognate, antigenic peptide. In the absence of an immune challenge, however, the TCR is continuously interacting with self-pMHC, which induces a relatively weak TCR signal known as tonic signaling. These homeostatic TCR:self-pMHC interactions …

Targeting The Phgdh-Mtor Metabolic Axis In Osteosarcoma, Richa Rathore

Arts & Sciences Electronic Theses and Dissertations

Altering cellular energy metabolism has been highlighted as one of the emerging hallmarks of cancer. The reprogramming of bioenergetic pathways towards enhanced glycolysis, rather than the mitochondrial oxidative phosphorylation indicative of normal cells, results in increased biomass production and is associated with the activation of various oncogenes. The increased or decreased expression of key metabolic enzymes has been identified as a potential family of biomarkers that could serve as the targets for novel metabolic-based therapies in cancer.

The serine, glycine, and one-carbon (SGOC) metabolism pathway consists of a series of enzymes and metabolites that drive protein and lipid production, enhanced …

Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm⁻²) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …

A Mechanistic And Genomic Analysis Of Molluscum Contagiosum Virus Immune Evasion, Ian Benjamin Harvey

Arts & Sciences Electronic Theses and Dissertations

Molluscum contagiosum virus (MCV) is a common human-specific poxvirus with a proclivity for

infecting children and the immune-compromised. A characteristic MCV infection is restricted to

the epidermal layers of the skin and can persist for weeks to years in an otherwise healthy

individual. The high clinical burden of MCV is at odds with our limited knowledge regarding how

it successfully evades the human immune response, which is in part due to the lack of an animal

model or cell line to propagate the virus. Through this dissertation, we have uncovered and

characterized a novel mechanism by which MC80, a protein …

Mechanisms Of Cross-Presentation By Cdc1s, Derek James Theisen

Arts & Sciences Electronic Theses and Dissertations

Classical dendritic cells (cDCs) are specialized antigen presenting cells that can be divided into distinct subsets based on the types of pathogens they respond to and the type of immune response they generate. The cDC1 subset is specialized in priming CD8 T cell responses through the process of cross-presentation. During cross-presentation, exogenous protein antigens are taken up by cDC1 and presented on MHCI molecules, allowing for the priming of CD8 T cells during conditions when DCs themselves are not directly infected. The ability to cross-present in vivo is unique to cDC1, and is essential for anti-viral responses and rejection of …

Phantoms To Placentas: Mr Methods For Oxygen Quantification, Kelsey Meinerz

Arts & Sciences Electronic Theses and Dissertations

Molecular oxygen (O2) is vital for efficient energy production and improper oxygenation is a hallmark of disease or metabolic dysfunction. In many pathologies, knowledge of tissue oxygen levels (pO2) could aid in diagnosis and treatment planning. The gold standard for pO2 measures in tissue are implantable probes, which are invasive, require surgery for placement, and are inaccessible to certain regions of the body. Methods for determining pO2 both non-invasively and quantitatively are lacking. The slight paramagnetic nature of O2 provides opportunities to non-invasively characterize pO2 in tissue via magnetic resonance (MR) techniques. As such, O2 can be treated as a …

Dendritic Cell Development And Function, Vivek Durai

Arts & Sciences Electronic Theses and Dissertations

Dendritic cells (DCs) are a group of immune cells that include both classical dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs). cDCs are further comprised of two distinct subsets, cDC1s and cDC2s, which play critical roles in the initiation of innate and adaptive immune responses. Understanding how these lineages develop and function is therefore paramount. All DCs require the receptor tyrosine kinase Flt3 and its ligand Flt3L for their development, but the loss of Flt3L in mice leads to a more severe DC deficiency than does the loss of Flt3. This has led to speculation that Flt3L can bind to …

The Enzymatic Function Of The Tir Domain: From Axon Degeneration To Innate Immunity, Kow Essuman

Arts & Sciences Electronic Theses and Dissertations

The Toll/Interleukin-1 Receptor (TIR) domain is an evolutionarily ancient protein domain conserved from bacteria to eukaryotes, and is an essential signaling component of innate immunity pathways. In animal innate immunity, TIR domains have primarily been described for their scaffolding function in assembling protein complexes in host defense. In plant immunity, TIR domains are key components of the intracellular Nucleotide Binding Leucine rich repeat (NLR) immune receptors that confer resistance to pathogens. These NLR receptors trigger cell death and an immune response upon activation, but their mechanism has remained elusive. In bacteria, TIR domain proteins have been suggested to function as …

Investigating Biological Mechanisms Of Radiation Resistance In Advanced Stage Cervical Cancer, Fiona Ruiz

Arts & Sciences Electronic Theses and Dissertations

The current standard of care treatment for locally advanced cervical cancer is curative intent pelvic radiation with concurrently administered platinum chemotherapy (CRT). This treatment strategy is effective for many patients, but 33-50% of patients treated with CRT develop disease recurrence. Metastatic and recurrent cervical cancer is an incurable condition, and many of the currently available treatments are associated with significant morbidity and mortality. Identifying these patients upfront is a challenge that clinicians face when developing treatment strategies. Previous studies used to catalog the genomic and transcriptomic landscape of cervical cancer lacked high quality corresponding clinical follow up data for patients, …

Quantitatively Studying Tissue Damage In Multiple Sclerosis Using Gradient Recalled Echo Mri Sequences, Biao Xiang

Arts & Sciences Electronic Theses and Dissertations

Multiple Sclerosis (MS) is an unpredictable, often disabling disease of the central nervous system (CNS) that disrupts the flow of information within the brain, and between the brain the body. MS is the most common progressive neurologic disease of young adults, affecting approximately 2.3 million people worldwide. It is estimated that more than 700,000 individuals are affected by MS in United States. While MS has been studied for decades, the cause of it is still not definite and a fully effective treatment for MS is not yet available. Magnetic resonance imaging (MRI) has been used extensively in MS diagnosis and …

The Role Of Tumor Stromal Discoidin Domain Receptor 2 (Ddr2) In Breast Cancer Metastasis., Samantha Van Hove Bayer

Arts & Sciences Electronic Theses and Dissertations

Characteristics of breast tumor stroma, including altered collagen architecture and increased stiffness, are known to contribute to tumor invasion and metastasis. However, the cellular and molecular mechanisms by which these changes occur are not fully understood. To address this question, we used a mouse genetic model to delete Discoidin Domain Receptor 2 (DDR2) from mouse tumor stromal cells and interrogated breast cancer associated fibroblasts (CAFs) to determine the molecular events downstream of DDR2 action that may lead to changes in the tumor extracellular matrix (ECM). Our work revealed that the action of DDR2 in breast stromal cells is required for …

Development Of Lc-Ms For The Identification And Characterization Of Non-Adjacent Dna Photoproduct Formation In G-Quadruplex Forming Sequences, Claudia Posadas

Arts & Sciences Electronic Theses and Dissertations

Ultraviolet light is well known to induce cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts in duplex DNA, which interfere with DNA replication and transcription. Recently, a new class of DNA photoproducts known as anti cyclobutanepyrimidine dimers have been discovered, which form in G-quadruplex forming sequences in solution. G-quadruplex structures have been proposed to form in human DNA telomeres and certain promoters in vivo but evidence for their existence has been lacking. Since anti-cyclobutante pyrimidine dimers have been shown to form in G-quadruplex forming sequences, their formation in irradiated human cells could be used to confirm the existence …