Biological Phenomena, Cell Phenomena, and Immunity Commons^™

Advancing Rna Virus Discovery And Biology With Whole Genome Sequencing, Mariah Katherine Taylor

Theses and Dissertations (ETD)

Two RNA virus families that pose a threat to human and animal health are Hantaviridae and Coronaviridae. These RNA viruses which originate in wildlife continue and will continue to cause disease, and hence, it is critical that scientific research define the mechanisms as to how these viruses spillover and adapt to new hosts to become endemic. One gap in our ability to define these mechanisms is the lack of whole genome sequences for many of these viruses. To address this specific gap, I developed a versatile amplicon-based whole-genome sequencing (WGS) approach to identify viral genomes of hantaviruses and severe acute …

Identification Of Effectors Of Synergistic Lethality In Candida Albicans-Staphylococcus Aureus Polymicrobial Intra-Abdominal Infection, Olivia Adele Todd

Theses and Dissertations (ETD)

Candida albicans, an opportunistic fungal pathogen, and Staphylococcus aureus, a ubiquitous pathogenic bacterium, are among the most prevalent causes of nosocomial infections and cause severe morbidity and mortality. Moreover, they are frequently coisolated from central venous catheters and deep-seated infections, including intra-abdominal sepsis. Relatively little is known about the complex interactions and signaling events that occur between microbes and even less so how microbial “cross-talk” shapes human health and disease.

Using a murine model of polymicrobial intra-abdominal infection (IAI), we have previously shown that coinfection with C. albicans and S. aureus leads to synergistic lethality whereas monomicrobial infection is nonlethal. …

Delineating The Upc2a Regulon In Candida Glabrata, Yu Li

Theses and Dissertations (ETD)

Candida glabrata is the second most common cause of invasive candidiasis. Intrinsic resistance has greatly limited the utility of the triazole antifungal, fluconazole, in the treatment of invasive fungal infection. The transcription factor Upc2 regulates the expression of sterol biosynthesis genes in yeast. Disrupting UPC2A in C. glabrata greatly increases its susceptibility to fluconazole (FLU) in both FLU-susceptible and -resistant clinical isolates. Therefore, the Upc2A and its target genes represent a potential pathway for overcoming FLU resistance in C. glabrata. We aimed to delineate the Upc2A regulon to determine its target genes involved in FLU resistance. Transcriptome sequencing (RNA-seq) analysis …

Characterization Of Genome-Wide Binding Of Nuclear-Factor I-X In Hematopoietic Progenitor Cells, Megan J. Walker

Theses and Dissertations (ETD)

We report that ectopic expression of Nfix in primary mouse HSPC extended their ex vivo culture from 20 to 40 days. HSPC overexpressing Nfix displayed hypersensitivity to supportive cytokines and reduced apoptosis when subjected to cytokine deprivation compared to controls. Ectopic Nfix resulted in elevated levels of c-Mpl transcripts and cell surface protein on primary murine HSPC as well as increased phosphorylation of STAT5, which is known to be activated down-stream of c-MPL signaling. Blocking c-MPL signaling by removal of its ligand, thrombopoietin (TPO), or addition of a c-MPL neutralizing antibody negated the anti-apoptotic effect of Nfix overexpression on cultured …

Roles Of Cytosolic Nucleic Acid Sensors In Cancer And Infection, Qifan Zhu

Theses and Dissertations (ETD)

Pattern recognition receptors are innate immune sensors that recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) with crucial roles in host defense against microbial infection, autoimmune diseases and cancer. Cytosolic nucleic acids including DNA and RNA originate from pathogens or self-cells, which form major groups of PAMPs and DAMPs. A range of nucleic acid sensors have evolved to sense various types of nucleic acids. How different DNA-sensing pathways regulate microbial infection and cancer is the focus of this dissertation.

Stimulator of IFN genes (STING) is a cytosolic innate immune sensor for cyclic dinucleotides that also serves a dual …

Pathogenicity And Protection Mediated By A Single Tcrβ In Experimental Autoimmune Encephalomyelitis, Tianhua Wu

Theses and Dissertations (ETD)

How the TCR repertoire, together with risk-associated major histocompatibility complex (MHC), imposes susceptibility for autoimmune disease is not fully understood. A small fraction of TCR α or β chains are “public”, and are shared by most individuals.High-throughput sequencing of the mouse TCRβ repertoire during myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmuneencephalomyelitis (EAE) identified a public TCRβ chain, TCRβ1, which was highly shared among individual mice and preferentially deployed during EAE. Retrogenic expression of TCRβ1 resulted in spontaneous early-onset EAE in mice with high penetrance and severity, despite being paired with a diverse endogenous TCRα repertoire. To further study autoimmunity conferred by …

Role Of Smarce1 And Bhlhe40 In Breast Cancer Metastasis, Aarti Sethuraman

Theses and Dissertations (ETD)

No abstract provided.

Protein Trafficking Of Bk Channel Β1 Subunits In Cerebral Artery Myocytes, Xue Zhai

Theses and Dissertations (ETD)

Rationale: Large-conductance calcium (Ca²⁺)-activated potassium channels (BK) are expressed in arterial myocytes to control arterial contractility. It is composed of pore- forming BKα and auxiliary β1 subunits. Auxiliary β1 subunits associate with BKα which modulate Ca²⁺ sensitivity of BK channel. Previous data showed that BKα locates at cell membrane, whereas β1 subunits are primarily intracellular which regulated by Rab11A- positive recycling endosomes. Endothelin-1 (ET-1), a vasoconstrictor, induces contraction of myocytes. ET-1 inhibits BK channel but mechanisms are not fully understood. It is unclear that vasoconstrictors regulate the cellular distribution of BK channels. Furthermore, BK channels are involved …

Role Of Dendritic Cells In Pathology Of Respiratory Syncytial Virus Infection In Neonates, Bishwas Shrestha

Theses and Dissertations (ETD)

Respiratory syncytial virus (RSV) is one of the leading causes of bronchiolitis in children. We have shown that neonatal mice respond to primary RSV infection with T helper type 2 (Th2) biased immune responses, which are enhanced following reinfection. Dendritic cells (DCs) including myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) play important roles in driving host responses to RSV infection. mDCs present antigens to help Th cells differentiate, and pDCs protect against viral infection through type I interferons (IFNs). Despite data demonstrating importance of mDCs and pDCs in protection against RSV, it has not been studied in an age appropriate …

Endosomal Trafficking As A Determinant Of Antifungal Tolerance In The Pathogenic Fungus Candida Albicans, Arturo Luis Luna

Theses and Dissertations (ETD)

Several important antifungal drugs inhibit the synthesis of ergosterol, a lipid that modulates the thickness, fluidity and permeability of fungal cell membranes. These include the azole antifungals, which block ergosterol biosynthesis by inhibiting lanosterol demethylase (Erg11p). The resulting depletion of cellular ergosterol and the accumulation of ‘toxic’ sterol intermediates are both thought to cause plasma membrane dysfunction and ultimately growth arrest. However, the effects of ergosterol depletion upon the function of intracellular membranes and organelles are not well described. The purpose of this study was to characterize the effects of azole treatment upon the integrity of the Candida albicans vacuole, …

The Nucleolar Protein Nucleophosmin Undergoes Liquid-Liquid Phase Separation With Arginine-Rich Nucleolar Proteins Through Weak, Multivalent Electrostatic Interactions, Jaclyn Alicia Cika

Theses and Dissertations (ETD)

Nucleoli are nuclear membrane-less organelles that are the sites for ribosome biogenesis and serve as sensors of cellular stress. Weak, multivalent protein-protein interactions and interactions between disordered, low complexity domains (LCDs) and rRNA have been shown to promote liquid-liquid phase separation (LLPS) in vitro, suggesting a basis for the liquid-like behavior of nucleoli. Nucleophosmin (NPM1), a multifunctional and highly abundant nucleolar protein, exhibits structural features associated with LLPS suggesting a role in nucleolar organization. Specifically, NPM1 forms a pentamer through its N-terminal oligomerization domain and can bind to rRNA through its C-terminal nucleic acid binding domain. Multiple acidic tracts throughout …

Pten Signaling In Regulatory T Cells And Inflammatory Disease, Sharad Krishna Shrestha

Theses and Dissertations (ETD)

Regulatory T (Treg) cells suppress CD4+ T cell responses during homeostasis and inflammation to prevent autoimmunity and other immune disorders. Although the transcriptional and epigenetic programs impacting Treg cell function have been extensively studied, the signaling and metabolic pathways underlying Treg stability and function are not fully understood. In this study, we determined the role of the phosphatase PTEN in Treg cells. We found that specific depletion of PTEN in Treg cells results in excessive TH1 and T follicular helper cells (TFH) responses, associated with elevated germinal center (GC) B cells and spontaneous development of autoimmune and lymphoproliferative disease in …

Toll-Like Receptors 2 And 9 Are Important For Innate Immune Cell Activation And Recruitment In Hypersensitivity Pneumonitis, Kelly J. Andrews

Theses and Dissertations (ETD)

Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by repeated inhalation of environmental antigens. The disease is characterized by alveolitis and granuloma formation; however, some patients develop chronic HP (CHP), a restrictive lung disease characterized by fibrosis. Previous studies revealed that neutrophils are recruited into the lung via a MyD88- dependent pathway and regulate disease severity through cytokine production. Toll-like receptors (TLRs) 2 and 9 recognize conserved molecular patterns present in bacteria, and signal through the adaptor molecule MyD88. The goal of my project is to investigate the role of TLRs 2 and 9 in the pathogenesis of HP …

Systems Biology Approach To Identifying Host Interactive Pathways Modulating The Severity Of Streptococcal Sepsis, Nourtan Fatthy Abdeltawab

Theses and Dissertations (ETD)

Clinical outcomes of infectious diseases are controlled by complex interactions between the host and the pathogen. Epidemiological, genetic and molecular studies in my mentor’s laboratory provided evidence that in invasive Group A streptococcal (GAS) infections, genetic variations in both bacteria and patients influenced the severity of GAS sepsis. Allelic variations in class II human leukocyte antigens (HLA) contributed significantly to differences in the severity of group A streptococcal sepsis caused by the same virulent strain of the bacteria. HLA class II molecules present streptococcal superantigens (SAgs) to T cells, and variations in HLA class II molecules can strongly influence SAg …