Medicine and Health Sciences Commons^™

Systems Genetics And Systems Biology Analysis Of Paraquat Effects In Bxd Recombinant Inbred Mice, Carolina Del Valle Torres Rojas

Theses and Dissertations (ETD)

Paraquat (PQ) is a chemical herbicide that is used in many countries including the United States. It is also highly acutely toxic to humans and has been used as a means of suicide. As PQ is applied mainly in agricultural settings, it moves to soil and well water. Chronic low dose exposure via drinking water may have adverse effects on humans, including increased risk for sporadic Parkinson’s disease (sPD). The etiology of sPD is unclear and the most accepted hypothesis states it is the result of the interaction between environmental factors and genetic susceptibility. Increasing evidence led us to infer …

Dissecting Drivers Of Basal Immunity And Acute Responses To Viral Infection, Aisha Nadia Hegab Souquette

Theses and Dissertations (ETD)

Heterogeneity in the human immune system can lead to limited vaccine efficacy, poor response to therapeutics, increased susceptibility to immune mediated diseases, and differential outcome to infection. Studies to date have suggested a role for biological, environmental, and genetic factors in immune variation; however, they are often focused on a specific subset of the population (e.g. ancestral group, age range) which can exclude phenotypes unique to a diverse population and bias results. To address this gap, we have utilized samples from healthy or influenza virus infected subjects from 8 distinct populations in 5 countries to conduct an integrative analysis of …

Role Of Cerebral Vasculature And Effect Of Circulating Exosomes In Propagation Of Systemic Inflammatory Responses Into The Central Nervous System, Mahesh Chandra Kodali

Theses and Dissertations (ETD)

Sepsis-associated encephalopathy (SAE) is an acutely progressing brain dysfunction induced by systemic inflammation. The mechanism of initiation of neuroinflammation during SAE, which ultimately leads to delirium and cognitive dysfunction, remains elusive. The goal of this project was to study the molecular events of SAE to capture its onset and progression into the central nervous system (CNS), and further identify the cellular players involved in mediating acute inflammatory signaling. Gene expression profiling on the cerebral vessels isolated from the brains of the mice treated with peripheral lipopolysaccharide (LPS) revealed that the cerebral vasculature responds within minutes to acute systemic inflammation by …

Attenuation Of Interferon Responses In The Obese Host And Ramifications For Influenza Virus Evolution, Rebekah Reed Honce

Theses and Dissertations (ETD)

The most insidious pandemic of modern life does not arise from an infectious agent but rather from malnutrition. With its global incidence tripling over the past three decades, obesity is a major public health concern. Obesity’s rising prevalence has also illuminated its impact on communicable diseases. Following the 2009 H1N1 influenza A virus pandemic, obesity was identified as a risk factor for increased disease severity and mortality in infected individuals. Obesity causes a chronic state of meta-inflammation with systemic implications for immunity, including delayed antiviral responses to influenza virus infection, poor recovery, and impaired immunological memory. However, the majority of …

Vitamin D Levels Affect Survival In A Bcr-Abl Acute Lymphoblastic Leukemia Mouse Model But Do Not Cause Vitamin-Drug Interactions, Kavya Annu

Theses and Dissertations (ETD)

It is a well-established phenomenon that dietary components containing CYP3A inducers or inhibitors if co-administered with drugs that are CYP3A4 substrates lead to marked drug-drug interactions. Because vitamin D is known to regulate intestinal CYP3A expression and gut CYP3A expression plays an important role in pre-systemic metabolism of CYP3A drugs, we determined the impact of vitamin D (VD3) status on systemic exposure and efficacy of chemotherapeutic agents that are CYP3A substrates. We employed VD3 sufficient and deficient mice to perform pharmacokinetics (PK) and anti-leukemic efficacy studies.

First, using hCYP3A4 transgenic mouse model we evaluated the intestinal, hepatic and renal expression …

Eukaryotic Initiation Factor 5a2 (Eif5a2) Contributes To Ovarian Tumor Growth And Metastasis, Guannan Zhao

Theses and Dissertations (ETD)

Ovarian cancer has the highest mortality rate among all gynecological malignancies due to lack of effective biomarkers for early diagnosis. The majority of ovarian cancer patients are already at an advanced stage when diagnosed. In addition, ovarian cancers often become chemoresistant and metastatic, and recur following initial chemotherapy.

Genetic Variation And Sex Mediate Differential Responses To ∆-9-Tetrahydrocannabinol Among Inbred Mice, Cory Parks

Theses and Dissertations (ETD)

The plant Cannabis sativa has been used by people for both recreational and medicinal use for thousands of years, but scientific investigation of the plant and its components didn’t begin until the early nineteen hundreds when Cannabis components known as phytocannabinoids were characterized and later isolated. In the 1970’s, ∆9-tetrahydrocannabinol (THC) was isolated and recognized as the major constituent responsible for the psychoactive and intoxicating effects associated with consumption of cannabis. This opened the door for intensive research in the field that lead to the discovery of the endogenous cannabinoid system and its associated receptors, effectors of signaling, and biosynthetic …

Veru-111 As An Oral Tubulin Inhibitor Suppressing Triple-Negative Breast Cancer And Evaluation Of Novel Tubulin Inhibitors For Cancer Therapy, Shanshan Deng

Theses and Dissertations (ETD)

Triple negative breast cancer (TNBC) has aggressive clinical features strongly associated with poorer overall prognosis and higher mortality rates relative to other molecular subtypes. FDA-approved drugs, such as paclitaxel, are effective in treating TNBC. Yet, treatment failure is commonly observed due to the development of acquired chemoresistance, which remains a clinical challenge for TNBC therapy.

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 …

Validation And Application Of A Novel Target-Based Whole-Cell Screen To Identify Antifungal Compounds, Christian Alexander Dejarnette

Theses and Dissertations (ETD)

Traditional approaches to drug discovery are inefficient and have several key limitations that constrain our capacity to rapidly identify and develop novel experimental therapeutics. To address this, we have devised a second-generation target-based whole-cell screening assay based on the principles of competitive fitness, which can rapidly identify target-specific and physiologically-active compounds. Briefly, strains expressing high, intermediate, and low levels of a preselected target protein were constructed, tagged with spectrally distinct fluorescent proteins (FPs), and mixed together. The pooled strains were then grown in the presence of various small molecules, and the relative growth of each strain within the mixed culture …

Conditional Loss Of Engrailed 1/2 In Rhombic Lip-Derived Neurons Increases Intrinsic Rhythmicity And Decreases Overall Variability Of Eupneic Respiration, Angela P. Taylor

Theses and Dissertations (ETD)

Evidence for a cerebellar role during cardiopulmonary challenges has long been established, but investigation into cerebellar involvement in eupneic breathing has been inconclusive. Given the view of the cerebellum (CRB) as a temporally coordinating structure, any investigation into the CRB during respiration must evaluate rhythm and variability of the respiratory sequence. In this study, we chose an elegant model of cerebellar neuropathology, Atoh1-En1/2 CKO, where mutant animals have conditional loss of the developmental patterning gene Engrailed 1/2 in rhombic lip-lineage neurons and exhibit a proportional scaling-down of neuron number in hypoplastic lobules of the CRB. We utilized whole-body unrestrained plethysmography …

The Characterization Of Hematopoiesis In Murine Fetal Bone Marrow, Trent Daniel Hall

Theses and Dissertations (ETD)

Hematopoietic stem cells (HSCs) and their downstream progenitors are a heterogeneous population of cells that are indispensable for lifelong hematopoiesis and are often utilized in the clinic for the treatment of hematologic maladies via hematopoietic stem cell transplantation (HSCT). Over several decades, it has been discovered that HSCs arise in the dorsal aorta of the developing embryo, migrate to the fetal liver (FL), and undergo a large expansion before reaching their final resting place in the bone marrow (BM). Many resources have been invested in understanding the roles of the different niches HSCs encounter along their journey. A greater understanding …

Genomic Instability And The Oncohistone H3k27m Drive Gliomagenesis In A Murine Model, Lee J. Pribyl

Theses and Dissertations (ETD)

Maintaining genome stability is crucial for human health and it is of particular importance in neural cells during early brain development. Genome maintenance occurs at two broad stages; surveillance during DNA replication and DNA damage repair in differentiating and mature cells. Neural cells are particularly sensitive to DNA strand breaks and defective DNA damage responses can result in detrimental effects on the nervous system, including cancer. Multiple DNA repair pathways play critical roles in preventing DNA damage accumulation in stem and neural progenitor cells. The mechanisms that protect progenitor genomes also suppress DNA mutations that can result in cancer. A …

Investigation Of A Novel Mitophagy Regulatory Pathway And Chemical Inducer, Jane E. Craig

Theses and Dissertations (ETD)

Mitochondria are vital organelles that coordinate cellular energy homeostasis and also have important roles in cell death. Therefore, the removal of damaged or excessive mitochondria through autophagy, a process called mitophagy, is critical for maintaining proper cellular function. Much of the research elucidating the mechanism and regulation of autophagy was performed in yeast cells, so there is still a lot of mystery surrounding how mitophagy is promoted and regulated in mammals in general and in different tissues. The most well understood mechanism involved in mitophagy is the PINK1-PARKN pathway. However, studies often rely on severe mitochondrial damage using CCCP that …

Mean Arterial Pressure In Acute Ischemic Stroke Study, Mary Angela Grove

Theses and Dissertations (ETD)

Background. There is little, if any, evidence available on the validation of blood pressure (BP) measurements obtained in the acute care setting. Despite this, acute stroke practitioners trust and rely on non-invasive blood pressure (NIBP) devices to guide acute ischemic stroke (AIS) patients’ treatment. Although systolic blood pressure (SBP) has been found to be the most unreliable measurement displayed on NIBP devices, treatment decisions for AIS are based on them. Today, 25 years after the FDA’s approval of alteplase, practitioners continue to use BP parameters of 185/110 and 180/105 to guide the initiation of alteplase bolus and infusion, although the …

Renal And Cardiovascular Outcomes Associated With Cannabis Use In Veterans With Advanced Chronic Kidney Disease Transitioning To Dialysis, Praveen Kumar Potukuchi

Theses and Dissertations (ETD)

Background: Legalization of cannabis and its constituents may lead to increased exposure of a higher number of consumers to cannabis use, including those with chronic kidney disease (CKD). We expect increase in cannabis use, especially, in patients with compromised kidney function. However, there is sparse literature on the effects of cannabis use on cardiorenal and mortality outcomes among patients with advanced CKD. Objectives: The main goal of the current study was to examine the effect of cannabis use on renal and cerebrovascular outcomes as well as mortality in patients with advanced CKD. Using a nationwide cohort of US veterans with …

Understanding Human Astrovirus From Pathogenesis To Treatment, Virginia Hargest

Theses and Dissertations (ETD)

While human astroviruses (HAstV) were discovered nearly 45 years ago, these small positive-sense RNA viruses remain critically understudied. These studies provide fundamental new research on astrovirus pathogenesis and disruption of the gut epithelium by induction of epithelial-mesenchymal transition (EMT) following astrovirus infection. Here we characterize HAstV-induced EMT as an upregulation of SNAI1 and VIM with a down regulation of CDH1 and OCLN, loss of cell-cell junctions most notably at 18 hours post-infection (hpi), and loss of cellular polarity by 24 hpi. While active transforming growth factor- (TGF-) increases during HAstV infection, inhibition of TGF- signaling does not hinder EMT induction. …

Mechanisms Of Bak Activation In The Initiation Of Mitochondrial Apoptosis, Geetika Singh

Theses and Dissertations (ETD)

Mitochondrial apoptosis is crucial for normal mammalian development and adult homeostasis being regulated by B-Cell Lymphoma-2 (BCL-2) proteins. Deregulation of BCL-2 proteins form the basis for myriad of human pathologies including cancer and autoimmune diseases. Therefore, BCL-2 proteins are considered key therapeutic targets. BCL-2 homologous antagonist/killer (BAK) is an effector of outer mitochondrial membrane (OMM) pemeabilization or mitochondrial poration. Despite progress in understanding BAK-mediated mitochondrial poration, the underlying multi-step mechanism is not clearly defined. Here, we provide mechanistic details on the early steps in this process related to BAK activation, including transient direct activation and autoactivation. We demonstrate for the …

Selective Targeting Of Cyp3a5 Through Chemical And Genetic Approaches, William C. Wright

Theses and Dissertations (ETD)

Cytochrome P450 enzymes function to catalyze a wide range of reactions important for various biological processes. In humans, the CYP3A subfamily is particularly critical for drug response. Within this family are CYP3A4 and CYP3A5, which collectively metabolize greater than half of all currently prescribed drugs. These promiscuous enzymes can bind a broad and structurally diverse array of compounds, in turn leading to an increased risk of their modulation via small molecules. In the case of CYP3A5, which is over-expressed in some cancers, this leads to chemoresistance. Such aberrant expression and corresponding drug resistance merit a need to selectively target CYP3A5. …

Biochemical And Structural Characterization Of The Atg8/Lc3 Lipidation Pathway, Yumei Zheng

Theses and Dissertations (ETD)

Atg8 and its eukaryotic orthologues LC3 and GARBARAP family proteins (referred here to Atg8 family proteins) play crucial roles in autophagy through their covalent ligation to lipids, typically phosphatidylethanolamine (PE), in a process known as lipidation. Lipidation of Atg8 family proteins regulates numerous facets of the autophagy process, including regulating expansion of the phagophore membrane, recruiting selected cargoes for degradation, and providing an autophagosome membrane-bound platform mediating dynamic interactions with other regulatory proteins. Atg8 family proteins are ubiquitin-like proteins (UBLs), and their lipidation involves a divergent UBL conjugation cascade including Atg7, Atg3, and Atg12–Atg5-Atg16 acting as E1, E2, and E3 …

Integrated Multimodal Genomic Analyses Reveal Novel Mechanisms Of Glucocorticoid Resistance In Acute Lymphoblastic Leukemia, Robert J. Autry

Theses and Dissertations (ETD)

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Much has been discovered in recent decades regarding ALL biology, and the outcome of patients with ALL has vastly improved, especially in pediatric ALL patients. Despite very promising overall cure rates, patients who relapse have a greatly decreased prognosis with survival rates ranging from 30-60%. These numbers stand to improve even further with new targeted therapies that seek to improve or maintain cure rates while reducing treatment related toxicities which affect patients both acutely and chronically. Glucocorticoids (GCs) are essential components of modern chemotherapeutic intervention for ALL. Resistance to glucocorticoids …

Unraveling Molecular Mechanisms Underlying The Development Of Unconventional T Cells, Daniel Eduardo Bastardo Blanco

Theses and Dissertations (ETD)

The thymus supports and guides the generation of a diverse repertoire of mature T cells from precursors derived from the bone marrow. In addition to conventional CD4 and CD8 T cells, innate-like T cells also develop in the thymus and share features of the adaptive and the innate immune system. These ‘unconventional’ T cells have emerging roles in tissue homeostasis and disease, but the molecular mechanisms underpinning their development remain elusive. In this study, we uncovered the roles of the molecules RAPTOR and PTEN in the thymic development of unconventional T cells. Capitalizing on genetic deletion of RAPTOR, we found …