Medical Sciences Commons^™

Molecular Characterization Of Glioblastoma Cancer Stem Cells, Jo Meagan Garner

Theses and Dissertations (ETD)

Malignant gliomas are locally aggressive, highly vascular tumors that have an overall survival time less than 14 months, and current therapies provide little improvement in the disease course and outcome. While glioblastoma multiforme (GBM) patients present uniform histological phenotypes, the molecular determinants of the disease vary considerably between individual cases resulting in complicated prognosis. The heterogeneity, aggressiveness and rapid tumor relapse of GBM is believed to be sustained by cancer stem-like cell populations that are able to initiate and maintain tumors. Although CSCs represent only a small fraction of cells within a tumor, their high tumor-initiating capacity and therapeutic resistance …

Preliminary Study On How Tumor Suppressor Nf2 Inhibits Transcriptional Coactivators Yap/Taz In The Developing Mouse Brain, Yu He

Theses and Dissertations (ETD)

Normal brain development requires precise coordination of neural progenitor proliferation and differentiation, the mechanism of which is not well known. Recently the tumor suppressor neurofibromatosis 2 (Nf2) was shown to regulate the balance of neural progenitor proliferation and differentiation in the developing mouse brain through the Hippo pathway effectors, transcriptional coactivators Yap/Taz. The molecular mechanism of how Nf2 regulates Yap/Taz is not understood. Here I showed that Nf2 regulated the Yap/Taz activity by decreasing the stability of Yap/Taz. The regulation was independent of Yap-S366 phosphorylation, which is required for Yap degradation. I also showed that Nf2 did not regulate Lats1/2 …

Persistant Gata2 Expression Promotes Self-Renewal Of Myeloid Progenitors And Blocks Lymphoid Differentiation., Satish Kumar Nandakumar

Theses and Dissertations (ETD)

The transcription factor GATA2 is highly expressed in hematopoietic stem cells (HSCs) and is downregulated during differentiation. Overexpression of GATA2 is frequently observed in acute myeloid leukemia. In previous studies, enforced expression of GATA2 using a MSCV GATA2 retroviral vector blocked differentiation of HSC and progenitors without inducing leukemia. We hypothesized that a lower dose of GATA2 can relieve the HSC block and eventually transform myeloid progenitors into leukemia stem cells. To test this hypothesis we generated a MSCV GATA2-ERT vector in which nuclear concentration of GATA2 can be regulated by Tamoxifen (TAM). The GATA2-ERT protein was confirmed to leak …

Characterization Of Cre Mouse Models To Target Cns Barriers For Generating Conditional Knockouts Of Abc Transporters, Rachel L. Scheib

Theses and Dissertations (ETD)

The central nervous system (CNS) includes the brain and spinal cord, where both possess a blood to brain and a blood to cerebrospinal fluid (CSF) barrier. The blood-brain barrier (BBB) and blood-CSF barrier (BCSFB) regulate the passage of many molecules to maintain and protect these sensitive organs from harmful xenobiotics (i.e. drugs, pollutants, etc.) or physiologic changes (i.e. glucose, ion, or water composition). These barriers also express ABC transporters, including P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP), which are known to contribute to efflux of endogenous toxins and therapeutics from the CNS. Pgp and BCRP expression and activity are …

Developmental Characterization Of The Choroid Plexus In Sialidosis (Neu1 Deficient) Mice, Danielle Lee Helton

Theses and Dissertations (ETD)

The lysosomal sialidase Neuraminidase-1 (Neu1) initiates the hydrolysis of sialoglycoconjugates by cleaving their terminal sialic acid residues. Neu1 creates a complex with the carboxypeptidase protective protein/cathepsin A (PPCA), which is necessary for its catalytic activation and its transport to the lysosomal compartment. In humans, a primary deficiency of this enzyme leads to a pediatric, catastrophic, neurodegenerative lysosomal storage disorder called sialidosis. Mice deficient in Neu1 exemplify the early-onset severe form of sialidosis. Our laboratory has recently discovered that loss of Neu1 exacerbates the process of lysosomal exocytosis (LyEXO) in various cell types by influencing the sialic acid content of lysosomal …

Determinants Of Upper Genital Tract Complications In A Chlamydial Urogenital Mouse Model, Enitra N. Jones

Theses and Dissertations (ETD)

Genital Chlamydia trachomatis infection is a major public health concern. Chlamydia is the most commonly reported infection in the United States and the most common bacterial sexually transmitted infection worldwide. Unrecognized infection endangers female reproductive health by serious complications such as Pelvic Inflammatory Disease, ectopic pregnancy, and involuntary infertility. Widespread Chlamydia control programs were implemented more than two decades ago to improve women's reproductive health but, despite initial success, the number of chlamydial infections reported have increased.

One of the hypotheses put forth to explain increased chlamydial reporting suggests that a longterm caveat of control initiatives is interference with the …

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 …

A Novel Mechanism Of Enhanced Susceptibility To Bacterial Pneumonia In Influenza-Infected Hosts, Hazem Elsayed Ghoneim

Theses and Dissertations (ETD)

Viruses such as influenza suppress host immune function by a variety of methods. This may result in a significant morbidity through several pathways, including facilitation of secondary bacterial pneumonia from pathogens such as Streptococcus pneumoniae. Lungresident alveolar macrophages (AMs) act as the first line of innate cellular immunity against respiratory bacterial pathogens, including pneumococcus. Therefore, they represent an attractive target for study Before investigating the impact of influenza infection on resident AMs, we first characterized different subsets of lung-resident macrophages in naïve mice using a novel in vivo labeling approach in conjunction with multicolor flow cytometric analysis and confocal microscopic …

Nkg2d Ligands In Cancer, Neha Das Gupta

Theses and Dissertations (ETD)

NK cell transplantation has been increasingly used to treat cancers that are resistant to chemotherapy. However, not all cancers are susceptible to NK cell killing. The prevalence and mechanisms of NK cell resistance have not been well elucidated. Because NKG2D is a major activating receptor on NK cells, we sought to test the hypothesis that NKG2D is the primary pathway in tumor cell recognition. Herein, we comprehensively assessed 20 cancer cell lines representing a broad array of cancer types. In line with our primary hypothesis, no cancer cell lines that expressed low levels of NKG2D ligands were susceptible to NK …

Full-Gestational Exposure To Nicotine And Ethanol Results In Long-Term Dysregulation In The Ventral Tegmental Area, Emily Elizabeth Roguski

Theses and Dissertations (ETD)

Nicotine is considered a gateway drug for other drugs of abuse. The majority of smokers that begin smoking in adolescence, continue into adulthood. Multiple factors have been linked with smoking initiation, including maternal smoking. Drug exposure during pregnancy has long been suspected to exert deleterious effects on the fetal brain. Concurrent use of smoking and drinking alcohol throughout pregnancy is an all too frequent occurrence in the human population especially in disadvantaged and younger women.

The present study investigated the potential contributing factors for the enhanced nicotine selfadministration as seen in offspring with gestational exposure to nicotine and ethanol (Nic+EtOH).* …

Attenuation Of Parenteral Nutritionassociated Liver Disease By Omega-3 Long-Chain Polyunsaturated Fatty Acids, Emma Monique Tillman

Theses and Dissertations (ETD)

No abstract provided.

Adenylyl Cyclase 2 Selectively Regulates Il-6 Expression In Human Bronchial Smooth Muscle Cells, Amy Sue Bogard

Theses and Dissertations (ETD)

Adenylyl cyclase (AC) catalyzes the formation of the ubiquitous second messenger cAMP. AC isoforms differ in their tissue distribution, cellular localization, regulation, and protein interactions, and most cells express multiple isoforms. We hypothesized that cAMP produced by different AC isoforms regulates unique cellular responses. Overexpression of individual isoforms had distinct effects on forskolin (Fsk)-induced expression of a number of known cAMP-responsive genes in human bronchial smooth muscle cells (BSMC) and human embryonic kidney cells (HEK-293). Most notable, in BSMC overexpression and activation of AC2 enhanced interleukin 6 (IL-6) expression, but overexpression of AC3 or AC6 had no effect. IL-6 production …

Erg11-Mediated Azole Resistance In Candida Albicans, Stephanie Ann Flowers

Theses and Dissertations (ETD)

Although many medically important Candida species are commensal to the gut or colonizers of the skin, these organisms have the propensity to cause disease in the event of a waning immune system. Clinical manifestations of infections with Candida species can range from superficial mucosal infections to deep organ involvement usually resulting from haematogenous spread of infection. Despite significant progress made in the management of patients with fungal infections, the emergence of antifungal resistant clinical isolates creates significant problem in regards to antifungal prophylaxis and empirical treatment strategies. Antifungal resistance is associated with high mortality rates and hefty medical costs. The …

Regulation Of Secretory Phospholipase A2 By Thyroid Hormone, Pragya Sharma

Theses and Dissertations (ETD)

Rationale: Low grade inflammation has been correlated with elevated risk of hepatic steatosis and atherosclerosis. Secretory phospholipase A2 group IIA (PLA2g2a) enhances the progression of several chronic inflammatory diseases including arthritis and atherosclerosis. The potential linkage of hypothyroidism with inflammation led us to examine the modulation of sPLA2 expression by thyroid hormone (T3) in liver.

Objective: Most of the studies of phospholipase A2 group IIA (PLA2g2a) have been conducted with macrophages and vascular smooth muscle cells with regard to atherosclerosis. The liver is one of the major contributors to the total pool of extracellular PLA2g2a. The aim of the present …

Identification Of Novel Hif1a Target Genes That Regulate Tumor Progression And Metastasis, Danielle L. Peacock

Theses and Dissertations (ETD)

Hypoxia is a hallmark of most solid tumors. In response to hypoxic stress tumor cells adapt by regulating survival, metabolism and angiogenesis. The heterodimeric HypoxiaInducible Factor (HIF) transcription factors are the master regulators of this response. HIFs play key roles in many critical aspects of cancer biology including angiogenesis, stem cell maintenance, metabolic reprogramming, invasion, metastasis and resistance to radiation therapy and chemotherapy. Overexpression of HIF-1α and HIF-2α has been documented in multiple human cancers and HIF-1 protein is over-expressed in ~30% of primary breast tumors and ~70% of metastases, which independently correlates with poor prognosis and decreased survival in …

Macromolecular Complexes Of Cystic Fibrosis Transmembrane Conductance Regulator Alter Fluid Transport In Inflammatory Bowel Disorders, Kavisha Arora

Theses and Dissertations (ETD)

Macromolecular complexes of cystic fibrosis transmembrane conductance regulator (CFTR) comprise of network of proteins that can regulate cAMP-/cGMP-activated CFTR chloride channel function. We report the physical and functional coupling of CFTR with nitric oxide (NO) producing enzyme-inducible nitric oxide synthase (iNOS) at the apical plasma membrane in inflammatory bowel disease (IBD). The complex formation requires the scaffolding protein Na+ /H+ exchanger regulatory factor 2 (NHERF2). We demonstrate that iNOS is overexpressed at or near the apical plasma membrane of gut epithelial cells in IBD and, through the stimulation of the NO-cGMP pathway, generates compartmentalized cGMP underneath the plasma membrane. This …

The Protumorigenic Role Of Caspase-8 In Neuroblastoma, Devin Drew Twitchell

Theses and Dissertations (ETD)

Neuroblastoma (NB), the most common extracranial solid tumor in children, accounts for 15% of cancer-related deaths in pediatric patients. Caspase-8 (casp8), a proapoptotic protein, is silenced in approximately, 50-70% of neuroblastoma patient samples. Loss of casp8 has been suggested to increase NB metastasis and correlated, in some studies, with advanced-stage NB. Furthermore, decreased casp8 expression may facilitate neuroblastoma tumorigenesis by protecting cells from cell death mediated by either integrins or chemotherapeutics. Paradoxically, casp8 expression is maintained in 30-50% of NB patient samples giving rise to the possibility that casp8 may provide selective advantages for NB tumorigenesis. Caspase-8 is shown to …

Virologic Factors Contributing To The Genetic Diversification Of Influenza Viruses Circulating In North American Swine, Thomas Paul Fabrizio Ii

Theses and Dissertations (ETD)

The purpose of this study was to determine mechanisms of reassortment of swine influenza viruses and determine if certain reassortant gene combinations can drive evolution and host adaptation in the context of the triple reassortant internal gene (TRIG) cassette. The TRIG contains a unique combination of a human polymerase basic 1 (PB1) gene with avian polymerase basic 2 (PB2) and polymerase acidic (PA) genes. The remaining internal genes, nucleoprotein (NP), matrix (M), and non-structural (NS) are of swine origin. This differs considerably from classical swine lineage viruses which are drifted variants of the 1918 pandemic with all swine origin genes. …

Functional Study Of Hemogen Knockout Mouse Model, Peng Gao

Theses and Dissertations (ETD)

Mouse Hemogen (Hemgn) is regarded as a homologue of human Erythroid Differentiation Associated Gene (EDAG). EDAG overexpression has been postulated for association with some leukemia cases. Meanwhile, Hemgn has been found to contribute to Hoxb4 mediated hematopoietic stem cell expansion. Based on these postulations and evidences, a Hemgn knockout mouse model has been generated to study its function in normal and stress hematopoiesis. I confirmed the Hemgn expression in hematopoietic organs including bone marrow and spleen, as well as round spematids in testis. Hemgn is expressed in mouse hematopoietic stem cells and erythroid progenitor cells. Moreover, Hemgn was also found …

Gene Therapy And Stem Cell Therapy To Improve The Outcome Of Human Islet Transplantation, Hao Wu

Theses and Dissertations (ETD)

Since its first introduction in 1990s, the Edmonton Protocol for human islet transplantation has helped more than 500 patients with type 1 diabetes worldwide and met great success from bench to bedside. The Edmonton Protocol involves isolating islets from a cadaveric donor pancreas by enzymatic digestion and infusing into the patient's portal vein. Each recipient usually receives islets from two or three donors for an optimal outcome and is dosed with two immunosuppressive drugs, sirolimus and tacrolimus and a monoclonal antibody drug daclizumab to prevent the graft rejection. However, despite the administration of immunosuppressive drugs and the recent improvement in …

Metabotropic Glutamate Receptor 5 In The Medial Prefrontal Cortex: Role In Cocaine Sensitization And Addiction, Kristin Marie Timmer

Theses and Dissertations (ETD)

Cocaine sensitization is associated with cocaine-induced hyperexcitability of pyramidal projection neurons within the medial prefrontal cortex (mPFC). Such hyperexcitability presumably results in increased glutamatergic input to reward-affiliated brain regions such as the ventral tegemental area (VTA) and nucleus accumbens (NAc), consequently facilitating drugseeking behavior. Metabotropic glutamate receptor 5 (mGluR5) has been implicated in cocaine addiction and demonstrated to increase neuronal excitability, therefore, the aim of the present study was to investigate the effect of intra-mPFC mGluR5 manipulation on behavioral and neurochemical sensitization and drug-seeking. Bilateral cannulae were implanted into the mPFC of male Sprague-Dawley rats and mGluR5 antagonist MTEP (15 …

N200 And P300 Evoked By Stimuli Straddling Category Boundary In Lexical Context, Ji Young Lee

Theses and Dissertations (ETD)

Background and Objectives: Event-related potentials (ERPs) like N200 and P300 have been reported to reflect the categorical perception of speech. The purpose of the present study is to explore whether these ERP components reflect the influence of lexical context on categorical perception. Findings may provide evidence for bottom-up or top-down processing of speech. Methods: On a seven step series of the /bi/-/pi/ continuum, a two-forced choice labeling test was administered in two conditions: /bi/ context (e.g. bee sting) and /pi/ context (e.g. pea soup). From the labeling results, Stimulus 1which is a prototypical /bi/ was selected for standard stimuli, and …

Hematopoietic Stem Cell Threshold Sensing Controls Regulatory Pathways Facilitating Clinically Relevant Ex Vivo Expansion For Stem Cell Transplantation, Andrew D. Lasiter

Theses and Dissertations (ETD)

The ex vivo expansion of hematopoietic stem cells (HSCs) for transplantation has threefold importance: 1.) First, because of the rarity of stem cells there often isn’t a sufficient supply obtainable from common sources for larger children and adults. 2.) Secondly, patient morbidity and time to hematopoietic reconstitution following myeloablative preconditioning is improved by administering a larger pool of HSCs. 3.) Lastly, gene therapies for hematological diseases still require a robust supply of HSCs to offset varying degrees of inefficiency in vector mediated transfection protocols. These reasons, and others, have been an impetus for many discoveries made within four primary subdivisions …

Mrp4 Is A Crucial Regulator Of Testosterone Biosynthesis, Jessica Ann Morgan

Theses and Dissertations (ETD)

The physiological role of multidrug resistance protein 4 (Mrp4) in the testes is unknown. It was discovered that Mrp4 is expressed primarily in mouse and human Leydig cells; however, there is no current evidence that Mrp4 regulates testosterone biosynthesis. The role of Mrp4 was investigated in Leydig cells where testosterone production is regulated by cAMP, an intracellular second messenger formed when the luteinizing hormone (LH) receptor (Lhr) is activated. As Mrp4 regulates cAMP, we compared testosterone levels in our Mrp4 WT and KO mice. Prepubertal KO mice had significantly reduced testicular testosterone, impaired gametogenesis, and disrupted cAMP homeostasis, resulting in …

Anti-Apoptotic Mcl-1 Localizes To The Mitochondrial Matrix And Couples Mitochondrial Fusion To Respiration, Rhonda Perciavalle

Theses and Dissertations (ETD)

MCL-1, an anti-apoptotic BCL-2 family member that is essential for the survival of multiple cell lineages, is also among the most highly amplified genes in cancer. Although MCL-1 is known to oppose cell death, precisely how it functions to promote survival of normal and malignant cells is poorly understood. Here, I report that different forms of MCL-1 reside in distinct mitochondrial locations and exhibit separable functions. On the outer mitochondrial membrane, a MCL-1 isoform acts like other anti-apoptotic BCL-2 molecules to antagonize apoptosis, whereas an amino-terminally truncated isoform of MCL-1 that is imported into the mitochondrial matrix is necessary to …

The Role Of Bip Nucleotide Exchange Factor Sil1 In Immunoglobulin Biosynthesis, Tyler Sanford

Theses and Dissertations (ETD)

BiP is an essential endoplasmic reticulum resident molecular chaperone of the HSP70 family that binds exposed hydrophobic regions of unfolded proteins. Substrates bound by BiP are protected from dangerous non-specific interaction with other unfolded proteins via their aggregation prone exposed hydrophobic regions, which are normally buried in the native state, and act as BiP binding targets. For these substrates to mature into the native state, BiP must be released. Like all HSP70 family members, cycles of BiP binding and release are nucleotide dependent and facilitated by two genres of cochaperones, HSP40s, and nucleotide exchange factors (NEFs). HSP40s function in stimulating …

Discovery Of Dihydroartemisinin And Dasatinib Drug Combination To Cure Pooroutcome Bcr-Abl+ Acute Lymphoblastic Leukemia, Harpreet Singh

Theses and Dissertations (ETD)

Oncogenic signaling by the Philadelphia chromosome-encoded BCR-ABL fusion kinase initiates and drives both Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myelogenous leukemia (CML). Food and Drug Administration (FDA)- approved BCR-ABL-specific kinase inhibitors (BCR-ABL–KIs) imatinib, dasatinib and nilotinib induce prolonged remissions in CML but poor leukemia-reduction and relapse-control in Ph+ ALL. The relative primary BCR-ABL–KI-resistance in Ph+ ALL patients carrying predominantly BCR-ABLWT disease cannot be attributed to drug-resistant BCR-ABL mutations (BCR-ABLMUTANTS), and remains poorly understood.

We established a cell-based platform to evaluate the modulation of anti-Ph+ ALL activity of drugs by both tumor-extrinsic cytokines normally present in the leukemia …

Cns Penetration Of Tyrosine Kinase Inhibitors In Mouse Models, Mohamed Elmeliegy

Theses and Dissertations (ETD)

For the past three decades, advances in the treatment of central nervous system (CNS) tumors such as malignant glioma have only been modest. One particular challenge facing treatment of brain tumors is the delivery of therapeutically effective concentrations of anti-cancer agents to the target site in the brain. The sanctuary of the brain is protected by several barrier systems such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). These barriers restrict the passage of anti-cancer drugs into the brain via several protective mechanisms.

In the present study, we used cerebral microdialysis sampling, a technique for sampling unbound …

Hp Turns 17: T Helper 17 Cell Response During Hypersensitivity Pneumonitis (Hp) And Factors Controlling It, Hossam Abdelsamed

Theses and Dissertations (ETD)

Hypersensitivity Pneumonitis (HP) is an interstitial lung disease caused by repeated inhalation of a wide range of environmental antigens. It is characterized by alveolitis, granuloma formation, and fibrosis. Since HP is a T cell-mediated disease, it is important to determine the type of T cell response associated with granuloma formation and the factors that control this response. We hypothesized that HP is associated with a predominant Th17 cell response where both T-bet and TLRs 2 and 9 are controlling T cell response during HP. The results demonstrated a predominant Th17 response associated with granuloma formation in the lungs of C57BL/6J …

The Molecular Basis Of Fitness And Transmissibility Of Neuraminidase Inhibitor Resistant Influenza A Viruses, Susu Duan

Theses and Dissertations (ETD)

Neuraminidase (NA) inhibitors including oral oseltamivir and inhaled zanamivir are among the first line of defense against influenza virus infection. Development of resistance to NA inhibitors is a huge drawback for limited options for the control of influenza. During the first decade of NA inhibitor use, the detection rates of resistance to both NA inhibitors had remained low in circulating influenza viruses. However, the 2008~2009 season was marked by a radical increase of prevalence of oseltamvir resistance from <1% to >90% in worldwide surveillance in less than a year. The resistance was solely linked to NA H275Y variants of seasonal H1N1 viruses, …