Medical Sciences Commons^™

Studies On The Leukocyte-Associated Ig-Like Inhibitory Receptor-1 Signaling Pathway In T Lymphocytes, Chidi Zacheaus

Theses and Dissertations (ETD)

Inflammation is a natural process in which the immune system concertedly responds to pathogens and abnormal cell growth to protect the host. For an efficient/effective immune response that circumvents tissue atrophy, a delicate balance between stimulatory and inhibitory mechanisms is essential for the proper functioning of the immune system. Immuno-receptor Tyrosine-based Inhibitory Motif (ITIM)-bearing receptors in immune cells, including T lymphocytes, play a major role in preventing autoimmune responses. Leukocyte-associated Ig-like Inhibitory Receptor 1 (LAIR-1) is one of ITIM-bearing receptors. The mechanism by which LAIR-1 attenuates T-cell response has yet to be completely understood. In this study, I investigated a …

Tcf4 Is A Key Mediator Of Cell Identity And Oncogenesis In Neuroblastoma, Nour Aljouda

Theses and Dissertations (ETD)

Neuroblastomas (NB) are embryonal childhood tumors that derive from the multipotent neural crest cells (NCCs) of the peripheral nervous system. NB accounts for more than 15% of all childhood cancer-related deaths. Despite the most intensive multimodal therapy, more than 50% of patients with high-risk NB relapse with often fatal, resistant disease. Novel therapies are desperately needed to improve cure rates. Previous studies proposed that the deregulation of normal neural crest developmental programs contributes to NB oncogenesis by retaining the highly migratory and proliferative traits of NCCs. Thus, activation or repression of neural crest developmental pathways have been implicated in NB …

A Design, Development, And Evaluation Of Bio-Patch For Myocardial Tissue Repair, Yaya Zhang

Theses and Dissertations (ETD)

Introduction. Ischemic heart disease (IHD) is a major concern of human health issue. The structural repair and functional recovery of injured hearts is a major challenge in the clinical setting. Preclinical studies over last 10 years have demonstrated the potential of using stem cells to treat IHD, but the efficacy of this therapy is jeopardized by uncontrollable migration and low survival of the injected stem cells. An approach based on tissue engineering enabling target-specific stem cell delivery such as cardiac patches has emerged as an alternative solution for stem cell therapy for IHD. It employs scaffold materials to engulf various …

Investigation Of Clinically Relevant Fluconazole Resistance Mechanisms In The Fungal Pathogen Candida Parapsilosis, Laura Anne Doorley

Theses and Dissertations (ETD)

Invasive candidiasis is a severe fungal infection associated with significant morbidity and mortality, particularly among the critically ill and immunocompromised. Candida parapsilosis is the most common non-albicans species causing invasive Candida infections in pediatric and neonatal populations worldwide and is particularly common in the countries of South America, Western Asia, Mediterranean Europe, and Southern Africa. For many of these countries, fluconazole and other triazoles are the first line antifungal agents used for effective treatment of invasive Candida infection. Until recently, rates of fluconazole resistance among C. parapsilosis isolates were relatively low, therefore the determination of clinically relevant resistance mechanisms in …

Physiologically-Based Pharmacokinetic (Pbpk) Modeling For The Preclinical Development Of Spectinamide Antibiotics, Keyur R. Parmar

Theses and Dissertations (ETD)

Despite being an ancient disease caused by Mycobacterium tuberculosis (Mtb) and after decades of research, tuberculosis (TB) still affects millions of people every year worldwide. In 2018, the World Health Organization (WHO) reported that 10 million people developed tuberculosis and 1.5 million died of the disease. With the increase in the multidrug-resistant (MDR) and extensively drug-resistant (XDR) cases, the treatment for TB with the standard first and second-line therapy is becoming increasingly difficult. Therefore, there is an urgent need to find new anti-TB drugs as combination partners of existing and experimental classes of antimicrobial agents to shorten and simplify the …

Computer-Aided Drug Discovery For Helicobacter Pylori, Nicole Ann Vita

Theses and Dissertations (ETD)

Helicobacter pylori is a high-priority drug-resistant pathogen and is currently the only bacteria considered to be a class I carcinogen and there is a critical need to identify novel chemical matter to treat H. pylori infections. Hp is responsible for greater than 60% of gastric cancer related deaths and 89% of all gastric cancer morbidities. In a previous study, our lab identified novel Hp thienopyrmidine inhibitors that target respiratory complex I, an essential enzyme in respiration. Respiratory complex I is a large asymmetric multidomain and membrane bound enzyme and due to these innate features, it is not practical for biophysical …

Methods Development In Inflammatory Bowel Disease, Andrew B. Steimke

Theses and Dissertations (ETD)

Inflammatory bowel disease (IBD) is a disease that is classified into two subtypes: ulcerative colitis (UC) and Crohn’s disease (CD). Symptoms can range from mild discomfort to requiring surgical intervention and affects approximately 1-in-200 adults in America alone, with global incidence rates increasing. While many treatments exist for IBD, perhaps the main reason for the lack of a cure is that there are many different pathogeneses that all lead to a very similar expression of symptoms. Over 240 IBD loci have been identified to date, yet the causative allele that drives the association has only been identified in ~60 of …

A Cloning-Free Recyclable System For Crispr-Cas9 Mediated Mutant And Reversion Construction In Candida Albicans Clinical Isolates, Amanda K. Vogel

Theses and Dissertations (ETD)

Candida albicans is a ubiquitous opportunistic fungal pathogen and one of the most prevalent causes of fungal diseases worldwide. The reference isolate SC5314 is one of the most widely used strains for both experimental and genetic studies, but it is becoming increasingly evident that genetic diversity in clinical isolates plays an important role in antifungal resistance, virulence, and pathogenicity. These recent discoveries highlight the need for genetic tools that are capable of investigating genes in multiple strain backgrounds. Here we build on the SAT1-flipper method and combine it with CRISPR-Cas9 technology to achieve cloning-free homozygous deletion in a single transformation …

Inflammatory Response Following Hemorrhagic Stroke: The Role Of Cytokines, Patrick Devlin

Theses and Dissertations (ETD)

Hemorrhagic stroke is a dangerous form of stroke resulting from the rupturing of weakened blood vessels, releasing blood that increases intracranial pressure and causes the death of surrounding tissue. Treatment options are improving but remain limited, as evidenced by this condition being characterized by high rates of mortality as well as long-term morbidity. Unregulated inflammatory responses that occur following injury may be partially to blame for these poor outcomes. In response to any injury, the immune system releases cytokines to recruit immune cell activation and promote inflammation. But after hemorrhagic stroke, whether aneurysmal subarachnoid hemorrhage (aSAH) or intracerebral hemorrhage (ICH), …

Targeting Myeloid Protein Kinase C Signaling To Overcome Immune Suppression And Improve Immunotherapy In Cancer, Mehdi Chaib

Theses and Dissertations (ETD)

Checkpoint immunotherapy unleashes T cell antitumor potential which has revolutionized cancer treatment showing unprecedented long-term responses. However, most patients do not respond to immunotherapy which often correlates with a dysfunctional or immunosuppressive myeloid compartment. Immunosuppressive myeloid cells comprise Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) and can suppress T cells via production of immunosuppressive factors. Conversely, efficient cytotoxic T cell priming is dependent on the ability of antigen-presenting cells (APCs), mainly conventional dendritic cells (cDCs) and macrophages, to present or cross-present tumor antigens to T cells. Thus, targeting immunosuppressive myeloid cells while simultaneously enhancing APCs represents a promising strategy …

The Role And Immunogenicity Of Cbfa2t3-Glis2 In Pediatric Acute Megakaryoblastic Leukemia, Elizabeth A. Garfinkle

Theses and Dissertations (ETD)

CBFA2T3-GLIS2 is the most prevalent fusion oncogene in pediatric acute megakaryoblastic leukemia in patients without Down syndrome (non-DS-AMKL) and is associated with an event free survival of only 8% even with high intensity chemotherapy and stem cell transplant in first remission. A cryptic inversion event on chromosome 16 joins the three nervy homology regions (NHR) of CBFA2T3 to the five zinc fingers of GLIS2. This configuration enables the encoded chimeric transcription factor to bind GLIS consensus sequences throughout the genome and recruit transcriptional activators and repressors to alter gene expression and enhance self-renewal capability. Few cooperating mutations have been identified …

A Neurophysiological Investigation Of Listening Effort In Normal Hearing Adults Using Fnirs And Pupillometry, Jessica Defenderfer

Theses and Dissertations (ETD)

Real-world conversations are often accompanied by some sort of interference that challenges the clarity of the speaker’s message, causing listeners to exert more effort to understand speech. Previous research has demonstrated that when listening to speech becomes difficult, various regions of the brain are recruited beyond those which engage during optimal listening conditions. However, the neural correlates that underly listening effort are not fully understood. Importantly, the pupillary response can be used to index listening effort, such that pupil size increases with increasing cognitive demand. I proposed that pupillometry can be used to characterize the cortical response, such that changes …

Cellular Dynamics And Disease Outcome Of Type 3 Streptococcus Pneumoniae Clinical Isolates Differ Between Strains, Taylor Rae Plunkett White

Theses and Dissertations (ETD)

Streptococcus pneumoniae is a bacterial pathogen that continues to be a major cause of disease around the world. It is not only the number one cause of bacterial pneumonia but also the cause of about 15% of the deaths of children under 5 around the world. There is a lot of research done on this organism, but with around 100 known serotypes and each one producing a unique capsule, there is still much more to be studied. The Etiology of Pneumonia in the Community (EPIC) study conducted by the CDC observed the burden of hospitalizations caused by pneumonia while determining …

Developing Targeted Therapies For T-Cell Acute Lymphoblastic Leukemia, Jianzhong Hu

Theses and Dissertations (ETD)

Introduction Acute lymphoblastic leukemia (ALL) is the most common cancer in children, and risk-adapted chemotherapies have dramatically improved the outcomes of this disease. Compared to B-cell ALL, T-cell ALL (T-ALL) is more aggressive and has worse outcomes from chemotherapy. There is a great unmet need to develop biomarkers and novel targeted therapies for this type of cancer. Working together with internal and external collaborators, we performed a large-scale pharmacotyping assay in over 300 primary ALL samples. By combining pharmacotypying and genomic profiling of these samples, we identified a substantial T-ALL population that showed strong response to dasatinib, a known ABL1 …

A Rodent Animal Model For Forelimb To Lower Jaw Reorganization In Primary Somatosensory Cortex (Si) Barrel Field, Violeta Pellicer Morata

Theses and Dissertations (ETD)

The goal of this study is to examine mechanisms underlying cortical reorganization in rat primary somatosensory (SI) cortex that follows forelimb deafferentation. The majority of human patients suffering from limb loss or brachial plexus avulsion injury, as well as patients that receive brachial plexus anesthesia, report phantom limb sensations/pain which are often associated with cortical reorganization. Patients with upper-limb deafferentation report sensations of the missing hand during tactile stimulation of the face, and this phenomenon has been termed hand-to-face remapping. We sought to develop a rodent model of deafferentation; our model system is the rat SI cortex barrel field present …

Mitophagy-Mediated Regulation Of Ros Homeostasis During Hsc Activation Contributes To Cell Fate, Amber Lynne Smith

Theses and Dissertations (ETD)

The ability of hematopoietic stem cells to self-renew and differentiate is required for the maintenance of all blood lineages under basal physiologic conditions and in response to inflammatory stress. The degradative capacity of the autophagy-lysosomal system is a determinant of hematopoietic stem cell (HSC) activation status with low autophagy predicting activation of HSCs, and autophagy deficiency causing the spontaneous loss of quiescence and HSC exhaustion. Although an increase in mitochondrial activity has been suggested as the cause of HSC depletion in autophagy-defective models, the contribution of mitophagy to HSC function remains to be elucidated. Here, we capitalized on the observation …

Characterizing And Overcoming Resistance To Aminomethylspectinomycins In Gram-Negative Bacteria, Nisha Das

Theses and Dissertations (ETD)

Spectinomycin (SPC) is a broad-spectrum aminocyclitol antibiotic. Its use in agriculture has led to widespread resistance in enteric bacteria, necessitating the development of more effective analogs. Aminomethyl spectinomycins (amSPC) are modified spectinomycins with increased potency against many bacterial species. These species include Legionella pneumophila, which harbors a chromosomally encoded aminoglycoside modifying enzyme (AME). In this study, we follow up on this observation and examine the extent to which the amSPCs are substrates for AMEs through adenylation (ANTs) and phosphorylation (APH). APH(9)-Ia and ANT(3")(9) were expressed in E. coli BL21(DE3) and purified using the Ni-affinity chromatography. The ability of AMEs to …

The Effect Of Cancer Cachexia Progression On The Feeding Regulation Of Skeletal Muscle Protein Turnover, Brittany R. Franch

Theses and Dissertations (ETD)

Cancer cachexia is defined as the unintentional loss of skeletal muscle mass with or without fat loss that cannot be reversed by conventional nutritional support. Cachexia occurs in ~20% of cancer patients. More specifically, 50% of lung cancer patients, the most common cancer worldwide, develop cachexia. Cachexia occurs most often in lung and gastrointestinal cancers, whereas breast and prostate have the lowest rate of cachexia. Cancer-induced cachexia disrupts skeletal muscle protein turnover (decreasing protein synthesis and increasing protein degradation). Skeletal muscle’s capacity for protein synthesis is highly sensitive to local and systemic stimuli that are controlled by mTORC1 and AMPK …

Identifying The Molecular Cause Of Extreme Endoplasmic Reticulum Dilation In Pediatric Osteosarcoma And Its Relationship To The Disease, Rachael Wood

Theses and Dissertations (ETD)

Pediatric osteosarcoma tumors are characterized by an unusual abundance of grossly dilated endoplasmic reticulum and an immense genomic instability that has complicated identifying new effective molecular therapeutic targets. Here we report a novel molecular signature that encompasses the majority of 108 patient tumor samples, PDXs and osteosarcoma cell lines. These tumors exhibit reduced expression of four critical COPII vesicle proteins that has resulted in the accumulation of procollagen-I protein within ‘hallmark’ dilated ER. Using CRISPR activation technology, increased expression of only SAR1A and SEC24D to physiologically normal levels was sufficient to restore both collagen-I secretion and resolve dilated ER morphology …

Environmental And Genetic Factors Affecting Bone Diseases And Phenotypes In Mouse Models, Wei Dong

Theses and Dissertations (ETD)

Bone diseases and phenotypes are affected in multiple ways. We focused on studying the effects of genetic and environmental factors, especially their impact on bone properties. Firstly, we investigated the effects of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid, on protecting bone from vitamin D deficiency in mice fed on a diet lacking or supplemented with vitamin D (VD). We found that the VD-deficient diet enhanced the length of femur and tibia bones (P<0.05), and increased bone volume (BV; P<0.01) and the trabecular bone volume fraction (BV/TV; P <0.01) compared to the D+ diet. When given BCP-containing diet, mice exhibited higher BV and bone mineral density (BMD; P<0.05) than the control group. The trabecular and cortical bone were also affected by VD and BCP. In addition, the inclusion of dietary BCP improved the serum concentrations of klotho (P < 0.05). In summary, these data indicate that BCP enhances the level of klotho in the serum, leading to improved bone properties and mineralization in an experimental mouse model. Under conditions lacking UV light, the D-deficient diet could affect multiple properties of bone, including trabecular and cortical bone, in mice. The D-deficient diet can also result in weight loss in mice.

My second project is to evaluate the bone properties in a mouse model with Il-1rn mutation. When knockout for IL-1rn, mice of Balb/c genomic background exhibited …

Ecology Of Hantaviruses In Rodent Reservoirs And Their Early Innate Immune Responses In Human Model Systems, Evan Peter Williams

Theses and Dissertations (ETD)

The spillover of zoonotic RNA viruses is responsible for a great deal of the disease outbreaks in human populations. These spillover events are set to continue due to anthropogenic and environmental changes that impact the distribution of these viruses. The viruses in the family Hantaviridae are classified as one of these emerging zoonotic RNA viruses. The spillover of the viruses in this family are responsible for two severe human diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). These viruses are distributed across the globe and are responsible for a large number of human disease cases with …

The Molecular Mechanisms Of Estrogen Receptor Α On Two Single Nucleotide Polymorphisms To Regulate Wnt Signaling In Osteoblasts, Sarocha Suthon

Theses and Dissertations (ETD)

Osteoporosis is the most common bone metabolic disorder, affecting over 200 million people globally. It is characterized by bone mass depletion and microarchitectural deterioration, leading to bone fragility and susceptibility to bone fracture. Genetic factors, estrogen deficiency, and dysregulation of the WNT signaling pathway contribute to the development of this disease. Genome-wide association studies have predicted that the single nucleotide polymorphisms (SNPs) rs2887571 and rs9921222 associate with low bone mass, but the mechanism of these SNPs has remained unknown. Analysis of osteoblasts from 112 different joint replacement patients reveals that the genotype of rs2887571 correlates with WNT5B expression, and the …

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 …

Role Of Smad2 And Smad3 On Adipose Tissue Development And Function, Roshan Kumari

Theses and Dissertations (ETD)

Introduction: Obesity and its associated metabolic syndrome are major medical problems worldwide including United States. Adipose tissue is the primary site of energy storage, playing important roles in health. Adipose tissue also has other critical functions, producing adipocytokines and contributing to normal nutrient metabolism, which in turn play important roles in satiety, inflammation, and total energy homeostasis. Activin A and activin B play important roles in maintaining body composition and energy homeostasis. This dissertation highlights the role of activin/SMADs signaling in adipose tissue development, function, and maintenance.

SMAD2/3 proteins are downstream mediators of transforming growth factor-β (TGFβ) family signaling, including …

Effects Of Genetics And Sex On Hippocampal Gene Expression And Adolescent Behaviors Following Neonatal Ethanol Exposure In Bxd Recombinant Inbred Mice, Jessica A. Baker

Theses and Dissertations (ETD)

Fetal alcohol spectrum disorders (FASD) are the leading preventable neurodevelopmental disorders in the western world. A hallmark symptom of FASD is cognitive and learning deficits that present in early childhood and continue throughout adulthood. Teratogenic effects of alcohol include increased cell death in the hippocampus, a brain region critically important in learning and memory. Genetics have been shown to have a role in the severity of alcohol’s teratogenic effect on the developing brain. Previous work in our lab identified differential vulnerability to ethanol-induced call death in the hippocampus using fourteen BXD strains and the two parental strains. The goal of …

Taste Learning In Insular Cortex: Plasticity Is Influenced By Experience Type, Stephanie Marie Staszko

Theses and Dissertations (ETD)

The gustatory cortex (GC) has long been studied as the main cortical area encoding taste stimuli and likely integrates sensory, visceral, and emotional information to guide taste-related behaviors. However, our understanding of cortical taste coding on a single-cell level has only become clear in recent years. The anatomical location of GC on the lateral and ventral surface of the brain makes it difficult to target with traditional imaging methods. Thus, much of what we know about cortical taste coding and cortical taste plasticity has been derived either from multiunit electrode recordings or anesthetized imaging experiments, techniques which lack the ability …

Iatrogenic Electrocautery Damage And Cellular-Based Corrosion Of Total Joint Arthroplasty Biomaterials, Kirsten Carol Miller

Theses and Dissertations (ETD)

Introduction. The number of patients undergoing a Primary Total Knee Arthroplasty (PTKA) has been increasing steadily each year. Of those PTKA patients, 20% report long-term pain and/or some functional deficit. Cobalt-Chromium-Molybdenum (CoCrMo) alloy is one of the most used materials in Total Joint Arthroplasty (TJA) implants due the material’s high strength, high corrosion resistance, and biocompatibility. The release of metal ions and potential occurrence of metallosis in TJA has been shown to be detrimental to the longevity of the implant. The mechanisms leading to this increase in metal ion concentrations have been up for debate, with some believing it is …

Near-Field Electrospinning And Characterization Of Biodegradable Small Diameter Vascular Grafts, William E. King Iii

Theses and Dissertations (ETD)

The ideal “off the shelf” tissue engineering, small-diameter (< 6 mm inner diameter (ID)) vascular graft hinges on designing a template that facilitates transmural ingrowth of capillaries to regenerate an endothelized neointimal surface. Previous traditionally electrospun (TES) approaches to create bioresorbable vascular grafts lack the pore sizes required to facilitate transmural capillary ingrowth required for successful in situ neovascular regeneration. Therefore, the ability to create scaffolds with program-specific architectures independent of fiber diameter via the relatively recent sub-technique of near-field electrospinning (NFES) represents a promising solution to create tissue engineering vascular grafts. These programmed large pore sizes are anticipated to promote in situ regeneration and improve the outcomes as well as the quality of life of patients with arterial disease.

In this dissertation, we manufactured via NFES as well as characterized biodegradable polydioxanone (PDO) small-diameter vascular grafts. Chapter 1 introduces the need for off-the-shelf, small-diameter vascular grafts to facilitate in situ regeneration, the process and pore size limitations of TES vascular grafts, and the promising use of NFES to develop precisely tailored PDO vascular grafts. Chapter 2 describes the process of NFES and details the current progress in NFES of biomedical polymers as well as the major limitations that exist in the field. Chapters 3, 4, and 5 contain primary research …

Genomic Characterization Of Sickle Cell Mouse Models For Therapeutic Genome Editing Applications, Kaitly Jensen Woodard

Theses and Dissertations (ETD)

Sickle cell disease (SCD) is caused by a mutation of the β-globin gene (HBB), resulting in abnormal hemoglobin molecules that polymerize when deoxygenated, forming “sickle” shaped red blood cells (RBCs). Sickle RBCs lead to anemia, multi-organ damage and pain crises, beginning the first year of life. The onset of symptoms coincides with the developmental switch of β-like globin gene expression from fetal stage γ-globin to adult stage β-globin, resulting in a shift from fetal hemoglobin (HbF, α2γ2) to adult hemoglobin (HbA, α2β2). Some individuals harbor rare genetic variants in the extended β-globin gene cluster that cause constitutively elevated postnatal HbF, …

Antibiotic Tolerance And Heteroresistance: Associated Fitness Costs And Potential In Evading Antibiotic Killing, Tina H. Dao

Theses and Dissertations (ETD)

Streptococcus pneumoniae is a prominent human pathogen that causes both invasive and non-invasive diseases, such as otitis media, pneumonia, meningitis, and bacteremia. Although it is frequently an asymptomatic colonizer of the human nasopharynx, S. pneumoniae is a major cause of morbidity and mortality in the immune compromised population, young children, and the elderly. Up until the 1970s, S. pneumoniae was susceptible to almost all antibiotics. Since then, this pathogen has gained resistance to a variety of antibiotic treatments, including beta-lactams, macrolides, and fluoroquinolones.

In the first chapter, we focused on fluoroquinolone resistance in S. pneumoniae. Fluoroquinolones are one of the …