Life Sciences Commons^™

Human Plcg2 Haploinsufficiency Results In A Novel Immunodeficiency, Joshua Brandon Alinger

Arts & Sciences Electronic Theses and Dissertations

NK cells are critical for the recognition and lysis of herpesvirus-infected cells. Patients with NK cell immunodeficiency may suffer from unusually severe and/or recurrent herpesvirus infections; however, the genetic cause is frequently unknown. PLCG2 encodes a signaling protein in NK cell and B cell receptor signaling, in which dominant-negative or gain-of-function mutations may cause cold urticaria, antibody deficiency, or autoinflammation. However, loss-of-function mutations and PLCG2 haploinsufficiency have never been reported in human disease. We examined 2 families with autosomal dominant NK cell immunodeficiency with dual high-dimensional techniques, mass cytometry and whole-exome sequencing, to identify the cause of disease. We identified …

Quantitative Characterization Of Microbial Ecologies In Dysbiosis And Infection, Eric Keen

Arts & Sciences Electronic Theses and Dissertations

In 1973, Theodosius Dobzhansky famously wrote that nothing in biology makes sense except in the light of evolution. Today, nearly 50 years later, little in microbiology – or in biology, for that matter – makes sense except in the light of genomics. Microbial genomics populates the field with innumerable testable hypotheses for evaluation in vitro and in vivo, allows us to monitor microbial populations in real time and at a massive scale, and underpins our approach to entire domains of microbiology, including microbial evolution. In this Thesis, I present three studies from my graduate research united by their common theme …

Structural Analysis And Vaccine Efficacy Of Hla Mutants, Kelly Tomaszewski

Arts & Sciences Electronic Theses and Dissertations

Staphylococcus aureus is a commensal of the human skin and also a major human pathogen. Currently, there has been no successful vaccine despite many approaches over the last two decades. S. aureus α-hemolysin (Hla), a potent cytotoxin, plays an important role in the pathogenesis of S. aureus diseases, through the activation of its receptor, ADAM10. We utilized three distinct Hla mutants with differing structural and ADAM10 binding properties to examine for vaccine efficacy. Our studies have demonstrated immunization with each vaccine candidate antigens provided significant protection against S. aureus skin infection yet elicited distinguishable immune responses. We have also generated …

Investigation Of Ifnγ-Induced Control Of Intracellular Pathogens, Michael Mcallaster

Arts & Sciences Electronic Theses and Dissertations

Genes required for the lysosomal degradation pathway of autophagy play key roles in topologically distinct cellular processes with significant physiologic importance. One of the first-described of these ATG gene-dependent processes is the requirement for a subset of ATG genes in interferon-γ (IFNγ)-induced inhibition of norovirus and Toxoplasma gondii replication. In this dissertation we identified novel components that are required for or that negatively regulate this immune mechanism. Enzymes involved in the conjugation of UFM1 to target proteins including UFC1 and UBA5, negatively regulated IFNγ-induced inhibition of norovirus replication via effects of Ern1. We identified and confirmed that IFNγ-induced inhibition of …

The Regulation Of Plasmodium Falciparum Metabolism By Haloacid Dehalogenase Proteins, Philip Frasse

Arts & Sciences Electronic Theses and Dissertations

Malaria is an enormous financial and public health burden for much of the world, infecting over 200 million and killing over 400,000 people every year. While much progress has been made combating malaria in the past few decades, those advances have slowed in recent years, partially due to the emergence of resistance to all known antimalarials used to date. To achieve the goal of eliminating malaria as a major global health problem, new therapeutics need to be developed, targeting novel categories of parasite biology. One poorly understood area of parasite biology is the regulation of various metabolic pathways. We have …

Type I Interferon Regulation Of Chikungunya Virus Pathogenesis, Marissa Christine Locke

Arts & Sciences Electronic Theses and Dissertations

Chikungunya virus (CHIKV) is an arthritogenic alphavirus that acutely causes fever as well as severe joint and muscle pain. Chronic musculoskeletal pain persists in a substantial fraction of patients for months to years after the initial infection, yet we still have a poor understanding of the mechanisms responsible for chronic disease. While replicating virus has not been detected in joint-associated tissues of patients with persistent arthritis nor in various animal models at convalescent time points, viral RNA is detected months after acute infection. However, there has been a lack of tools to study the mechanisms of chronic CHIKV disease. To …

Copper-Mediated Regulation Of A Traditional Iron Uptake System In Uropathogenic Escherichia Coli., George Lwanga Katumba

Arts & Sciences Electronic Theses and Dissertations

Transition metals constitute an important part of the host-pathogen interface. Iron is an essential nutrient that functions as a cofactor for numerous bacterial and host proteins, as either a ligand for oxygen in carrier proteins or an enzyme catalytic site due to its natural redox properties. As part of the innate immune response, infected hosts sequester iron from pathogens to limit their growth, a phenomenon known as nutritional immunity. On the other hand, copper ions are deployed at infection sites as a potent antimicrobial agent to kill bacteria. The ability to survive within multiple, often harsh, microenvironments is fundamental to …

Investigating The Role Of Bladder Epithelial Stem Cells In Bladder Mucosal Remodeling And Defense Against Infection, Seongmi Kim Russell

Arts & Sciences Electronic Theses and Dissertations

Urinary tract infections (UTIs) can be highly recurrent, and the mechanism(s) governing recurrence susceptibility are mostly unknown. Here I demonstrate bladder epithelial (urothelial)-intrinsic trained immunity as part of a differential mucosal remodeling response to an initial UTI. I established urothelial stem cell (USC) lines from isogenic mice with different UTI histories (naïve, chronic, or self-resolving) and discovered 2880 differential genome-accessible regions, indicating differential epigenetic reprogramming dependent on infection history. Differentiation of USC lines in vitro resulted in polarized urothelial cultures that recapitulated distinct remodeling morphologies seen in vivo and exhibited altered gene expression, including genes involved in cell death pathways. …

Regulation Of Host-Microbe Interactions In Autoimmunity And Antiviral Immunity By Cytosolic Nucleic Acid Sensing And Interferon Signaling, Derek Jerome Platt

Arts & Sciences Electronic Theses and Dissertations

Cytosolic nucleic acid sensing and interferon (IFN) signaling are central to the host immune response to microbial pathogens. However, dysregulation of immunological pathways such as these can result in devastating autoimmune disease. In order to provide a robust immune response to pathogen without causing harm to self, the host immune system must engage in a delicate balancing act, interacting with microbes and determining whether they are commensal or pathogenic. The cGAS-STING pathway is a key regulator of host-microbe interactions by cytosolic nucleic sensing and IFN signaling. Loss of function in the cGAS-STING pathway leads to increased susceptibility to pathogenic threats, …

Gut Reactions: Quantitative Predictions Of The Responses Of Human Gut Microbiota To Medical Interventions, Amy Elizabeth Langdon

Arts & Sciences Electronic Theses and Dissertations

The collection of microbes known as the human microbiome perform vital functions for their host, and when this community becomes unhealthy, its dysbiosis is implicated in a myriad of diseases. The gut microbiota in particular are known to suppress colonization of opportunistic pathogens, regulate the immune system, aid in nutrient breakdown, produce vitamins, and a growing number of other functions. In order to intervene in a dysbiotic microbial ecology, we can try to remove unwanted microbes or try to recolonize the gut with microbes expected to be beneficial. This dissertation provides an overview of the state of medical interventions for …

The Roles Of Capsular Polysaccharides And Diet In The Immune Response To A Bacteroides Thetaiotaomicron Antigen, Samantha Hsieh

Arts & Sciences Electronic Theses and Dissertations

The environment is well recognized to modulate immune responses within the intestinal mucosa in a general fashion. However, the connection between the effects of the environment on the immune response directed towards specific intestinal microbes is unclear. Progress in this area has been hampered by the lack of a model system in which the immune responses to a specific antigen in a gut symbiont can be examined. To this end, we developed a novel CD4+ T cell model, termed BθOM, that is specific for a dominant antigen in the gut symbiont Bacteroides thetaiotaomicron (B. theta). In this work, we use …

Genetic Variations In The Regulation And Biosynthesis Of Polycyclic Tetramate Macrolactams, Yunci Qi

Arts & Sciences Electronic Theses and Dissertations

Streptomyces are Gram-positive and filamentous bacteria with high-G+C genomes, which have yielded over half of all clinically used antibiotics plus many other useful compounds. Genome analyses indicate that these bacteria possess biosynthetic gene clusters (BGCs) encoding for many more antibiotic-like compounds than they are known to produce. The apparent silence of many BGCs poses a significant roadblock to genome-mining efforts for novel drugs. To understand BGC silence, I compared several Streptomyces that harbor the widespread BGC for polycyclic tetramate macrolactam (PTM) antibiotics to explore the genetic variations that differentiate robustly expressed BGCs from silent BGCs. To test the prevalent hypothesis …

Examining Early Interactions Between Innate Airway Resident Immune Cells And Mtb-Specific Factors During Pulmonary Infection With Mycobacterium Tuberculosis, Micah D. Dunlap

Arts & Sciences Electronic Theses and Dissertations

Mycobacterium tuberculosis (Mtb) is the leading cause of death by an infectious agent in the world today, infecting roughly one quarter of humans. Despite this, the mechanisms of early pathogenesis and host protective innate immune responses remain poorly understood and uncharacterized.

Lung resident Alveolar Macrophages (AMs) are the first host contact with Mtb bacilli after inhalation and are thus key mediators of the early pulmonary immune response. AMs are generally believed to reside entirely in the airway, but it was recently demonstrated that they have the capacity to egress and enter into granulomas during pulmonary infection with hypervirulent Mtb. Furthermore, …

Ascension And Adhesion Of Uropathogenic Escherichia Coli During Pyelonephritis, Lisa Kristine Mclellan

Arts & Sciences Electronic Theses and Dissertations

The ability of uropathogenic Escherichia coli (UPEC) to successfully establish an infection within the urinary tract relies on the pathogen to be able to navigate the complex interactions between pathogen and host. During a urinary tract infection (UTI), UPEC must ascend, adhere, and form bacterial communities in various infection niches, from the bladder (cystitis) to the kidneys (pyelonephritis). Each of these steps is critical for bacterial survival, and host and pathogen factors required at each stage can vary depending on host sex and anatomic niche. Preclinical modeling of pyelonephritis and sex effects on UTI has been limited due to the …

Prodrug Activation In Staphylococci And The Implications For Antimicrobial Development, Justin J. Miller

Arts & Sciences Electronic Theses and Dissertations

Antibiotic resistance is an increasing concern for global health care, with some estimates suggesting that 10 million people will die from antibiotic resistant infections in the year 2050. Fueling this prospect, few antimicrobials are being actively developed and recently commercial entities have fled from the development of new anti-infectives. New antimicrobials and drug development strategies are urgently needed to revitalize this critical pipeline. While many putative antibiotics demonstrate promising in vitro potency, they routinely fail in vivo due to poor drug-like properties (e.g. oral bioavailability, serum-half life, toxicity) resulting in overly expensive drug development pipelines. Fortunately, drug-like properties can be …

Investigating The Integration-Independent Role Of Hiv-1 In In The Viral Life Cycle, Jennifer Elliott

Arts & Sciences Electronic Theses and Dissertations

Human immunodeficiency virus type 1 (HIV-1) relies on a handful of essential enzymes for replication. Among these, the viral integrase enzyme (IN) plays a pivotal role in the viral life cycle by catalyzing the integration of the reverse-transcribed viral DNA into the host chromosome. While integration is the canonical role of IN, new research has uncovered an additional vital role for IN during virion morphogenesis. This dissertation elucidates how IN contributes to proper packaging of the viral RNA genome (vRNA) within the viral capsid and examines the fate of improperly formed viral particles in target cells.IN is proposed to mediate …

Understanding The Molecular Mechanisms Of Photoferrotrophy And Phototrophic Extracellular Electron Uptake, Dinesh Gupta

Arts & Sciences Electronic Theses and Dissertations

Several anoxygenic phototrophs grow by utilizing soluble iron or insoluble mixed-valence iron minerals (such as rust) as electron donors to fix carbon dioxide using light energy, a process called photoferrotrophy. Photoferrotrophs can also use electron donors such as poised electrodes that serve as proxies for rust via phototrophic extracellular electron uptake (EEU). Despite the recognition that these two related microbial processes contribute to various biogeochemical cycles such as iron and carbon, the electron uptake mechanisms underlying photoferrotrophy and phototrophic EEU are poorly understood. To address the key knowledge gaps in our understanding of these microbial metabolisms, here we characterized Rhodopseudomonas …