Life Sciences Commons^™

Analysis Of Band 4.1b In Integrin-Mediated Cell Adhesion And Signaling, Youngsin Jung

Dissertations and Theses (Open Access)

Band 4.1B is a cytoskeletal adaptor protein that regulates various cellular behavior; however, the mechanisms by which Band 4.1B contributes to intracellular signaling are unclear. This project addresses in vivo and in vitro functions for Band 4.1B in integrin-mediated cell adhesion and signaling. Band 4.1B has been shown to bind to β8 integrin, although cooperative functions of these two proteins have not been determined. Here, functional links between β8 integrin and Band 4.1B were investigated using gene knockout strategies. Ablation of β8 integrin and Band 4.1B genes resulted in impaired cardiac morphogenesis, leading to embryonic lethality by E11.5. These embryos …

Delineating The Mechanism(S) Of Bdnf/Trkb Mediated Proliferation In Neuroblastoma, Timothy C. Graham

Dissertations and Theses (Open Access)

Delineating the mechanism(s) of BDNF/TrkB mediated proliferation in Neuroblastoma

Timothy Christopher Graham, B.S.

Supervisory Professor: Patrick Zweidler-McKay, MD/PhD

Neuroblastoma is the most common extra-cranial solid tumor in children, arising from neural crest precursor cells.  The neurotrophin receptors (TrkA/B/C) have been implicated as important prognostic markers, linking the biology of the tumor to patient outcome.  High expression of TrkA and TrkC receptors have been linked to favorable biological features and high patient survival, while TrkB is expressed in unfavorable, aggressive tumors.  Several studies suggest that high levels and activation of TrkB by its ligand brain-derived neurotrophic factor (BDNF) stimulates tumor cell …

Mechanisms Regulating The P120-Catenin/Kaiso Pathway, Ji Yeon Hong

Dissertations and Theses (Open Access)

The Wnt pathways contribute to many processes in cancer and developmental biology, with β-catenin being a key canonical component. P120-catenin, which is structurally similar to β-catenin, regulates the expression of certain Wnt target genes, relieving repression conferred by the POZ/ zinc-finger transcription factor Kaiso. In my first project, employing Xenopus embryos and mammalian cell lines, I found that the degradation machinery of the canonical Wnt pathway modulates p120-catenin protein stability, especially p120 isoform-1, through mechanisms shared with b-catenin. Exogenous expression of destruction-complex components such as GSK3b or Axin promotes p120-catenin degradation, and consequently, is able to rescue developmental phenotypes resulting …

Atm Signaling To Tsc2: Mechanisms And Implications For Cancer Therapy, Angela Alexander

Dissertations and Theses (Open Access)

Ataxia telangiectasia mutated (ATM) is a critical component of the cellular response to DNA damage, where it acts as a damage sensor, and signals to a large network of proteins which execute the important tasks involved in responding to the damage, namely inducing cell cycle checkpoints, inducing DNA repair, modulating transcriptional responses, and regulating cell death pathways if the damage cannot be repaired faithfully. We have now discovered that an additional novel component of this ATM-dependent damage response involves induction of autophagy in response to oxidative stress. In contrast to DNA damage-induced ATM activation however, oxidative stress induced ATM, occurs …

Role Of Synapsin In Long-Term Synaptic Facilitation In Aplysia, Anne Hart

Dissertations and Theses (Open Access)

Enhanced expression of the presynaptic protein synapsin has been correlated with certain forms of long-term plasticity and learning and memory. However, the regulation and requirement for enhanced synapsin expression in long-term memory remains unknown. In the present study the technical advantages of the marine mollusc Aplysia were exploited in order to address this issue. In Aplysia, learning-induced enhancement in synaptic strength is modulated by serotonin (5-HT) and treatment with 5-HT in vitro of the sensorimotor synapse induces long-term facilitation (LTF) of synaptic transmission, which lasts for days, as well as the formation of new connections between the sensory and …

Cocaine Dependence: The Role Of Serotonin Genes In, Lorena Maili

Dissertations and Theses (Open Access)

Animal studies have shown that behavioral responses to cocaine-related cues are altered by serotonergic medications. The effects of pharmacological agents on serotonin receptors 2a (5-HT2A) and 2c (5-HT2C), have yielded results suggesting that selective 5-HT2A antagonists and 5-HT2C agonists promote the disruption of cocaine-associated memories. One measure of cocaine related cues in humans is attentional bias, in which cocaine dependent individuals show greater response latency for cocaine related words than neutral words. Data from our laboratory shows that cocaine dependent subjects have altered attentional bias compared to controls. The purpose of this thesis was to investigate the role of the …

Defining The Role Of Egfr Acetylation In Cellular Processes: Clinical Implications, Hui Song

Dissertations and Theses (Open Access)

Epidermal growth factor receptor (EGFR) is a cell membrane tyrosine kinase receptor and plays a pivotal role in regulating cell growth, differentiation, cell cycle, and tumorigenesis.  Deregulation of EGFR causes many diseases including cancers.  Intensive investigation of EGFR alteration in human cancers has led to profound progress in developing drugs to target EGFR-mediated cancers.  While exploring possible synergistic enhancement of therapeutic efficacy by combining EGFR tyrosine kinase inhibitors (TKI) with other anti-cancer agents, we observed that suberoylanilide hydroxamic acid (SAHA, a deacetylase inhibitor) enhanced TKI-induced cancer cell death, which further led us to question whether SAHA-mediated sensitization to TKI was …

Molecular Mechanism By Which The Escherichia Coli Nucleoid Occlusion Factor, Slma, Keeps Cytokinesis In Check, Nam K. Tonthat

Dissertations and Theses (Open Access)

Cell division or cytokinesis is one of the most fundamental processes in biology and is essential for the propagation of all living species. In Escherichia coli, cell division occurs by ingrowth of the membrane envelope at the cell center and is orchestrated by the FtsZ protein. FtsZ self-assembles into linear protofilaments in a GTP dependent manner to form a cytoskeletal scaffold called the Z-ring. The Z-ring provides the framework for the assembly of the division apparatus and determines the site of cytokinesis. The total amount of FtsZ molecules in a cell significantly exceeds the concentration required for Z-ring formation. Hence, …

Cop 9 Signalosome Subunit 6 Stabilizes Cop1, A Novel E3 Ubiquitin Ligase For 14-3-3Σ, Hyun Ho Choi

Dissertations and Theses (Open Access)

14-3-3σ, a gene upregulated by p53 in response to DNA damage, exists as part of a positive-feedback loop which activates p53 and is a human cancer epithelial marker downregulated in various cancer types. 14-3-3σ levels are critical for maintaining p53 activity in response to DNA damage and regulating signal mediator such as Akt. Here, we identify Mammalian Constitutive Photomorphogenic 1 (COP1) as a novel E3 ubiquitin ligase for targeting 14-3-3σ through proteasome degradation. We show for the first time that COP9 signalosome subunit 6 (CSN6) associates with COP1 and is involved in 14-3-3σ ubiquitin-mediated degradation. Mechanistic studies show that CSN6 …

Developmental And Cellular Functions Of Delta-Catenin, Dongmin Gu

Dissertations and Theses (Open Access)

Catenins have diverse and powerful roles in embryogenesis, homeostasis or disease progression, as best exemplified by the well-known beta-catenin. The less studied delta-catenin likewise contains a central Armadillo-domain. In common with other p120 sub-class members, it acts in a variety of intracellular compartments and modulates cadherin stability, small GTPase activities and gene transcription. In mammals, delta-catenin exhibits neural specific expression, with its knock-out in mice correspondingly producing cognitive defects and synaptic dysfunctions.

My work instead employed the amphibian, Xenopus laevis, to explore delta-catenin’s physiological functions in a distinct vertebrate system. Initial isolation and characterization indicated delta-catenin’s expression in Xenopus. Unlike …

Altered Responses To Endoplasmic Reticulum Stress In Pancreatic Cancer, Jennifer H. Choe

Dissertations and Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) represents the fourth most common cause of cancer-associated death in the United States. Little progress has been made in understanding how proteotoxic stress affects rapidly proliferating pancreatic tumor cells. Endoplasmic reticulum (ER) stress occurs when protein homeostasis in the ER lumen is perturbed. ER stress activates the unfolded protein response (UPR) to reduce the protein load in the ER. Under conditions of moderate ER stress, the UPR promotes cell cycle arrest which allows time for successful protein load reduction and enables cell survival. However, under conditions of high levels of ER stress the UPR induces cellular …

Investigating The Effects Of Silencing Epha2 In Metastatic Breast Cancer Cells, Stephanie Erzinger

Dissertations and Theses (Open Access)

EphA2, also known as ECK (epithelial cell kinase), is a transmembrane receptor tyrosine kinase that is commonly over-expressed in cancers such as those of the prostate, colon, lung, and breast. For breast cancers, EphA2 overexpression is most prominent in the ER-negative subtype, and is associated with a higher rate of lung metastasis. Studies conducted to demonstrate the role of EphA2 in a non-cancerous environment have shown that it is very important in developmental processes, but not in normal adult tissues. These results make EphA2 a prospective therapeutic target since new therapies are needed for the more aggressive ER-negative breast cancers. …

The Neural Substrates Of Multisensory Speech Perception, Audrey R. Nath

Dissertations and Theses (Open Access)

Comprehending speech is one of the most important human behaviors, but we are only beginning to understand how the brain accomplishes this difficult task. One key to speech perception seems to be that the brain integrates the independent sources of information available in the auditory and visual modalities in a process known as multisensory integration. This allows speech perception to be accurate, even in environments in which one modality or the other is ambiguous in the context of noise. Previous electrophysiological and functional magnetic resonance imaging (fMRI) experiments have implicated the posterior superior temporal sulcus (STS) in auditory-visual integration of …

Stromal Derived Growth Factor Alpha (Sdf-1Α) Induces The Differentiation Of Bone Marrow Progenitor Cells (Bmcs) Into Pericytes By Regulating Platelet Derived Growth Factor B (Pdgf-B) Transcription, Randala Hamdan

Dissertations and Theses (Open Access)

We previously demonstrated that bone marrow cells (BMCs) migrate to TC71 and A4573 Ewing’s sarcoma tumors where they can differentiate into endothelial cells (ECs) and pericytes and, participate in the tumor vascular development. This process of neo-vascularization, known as vasculogenesis, is essential for Ewing’s sarcoma growth with the soluble vascular endothelial growth factor, VEGF₁₆₅, being the chemotactic factor for BMC migration to the tumor site. Inhibiting VEGF₁₆₅ in TC71 tumors (TC/siVEGF_7-1) inhibited BMC infiltration to the tumor site and tumor growth. Introducing the stromal-derived growth factor (SDF-1α) into the TC/siVEGF_7-1 tumors partially restored vasculogenesis …

The Role And Mechanism Of The Homeobox Gene Dlx4 In Transforming Growth Factor-B Resistance In Cancer, Bon Q. Trinh

Dissertations and Theses (Open Access)

Transforming growth factor-b (TGF-b) is a cytokine that plays essential roles in regulating embryonic development and tissue homeostasis. In normal cells, TGF-b exerts an anti-proliferative effect. TGF-b inhibits cell growth by controlling a cytostatic program that includes activation of the cyclin-dependent kinase inhibitors p15^Ink4B and p21^WAF1/Cip1 and repression of c-myc. In contrast to normal cells, many tumors are resistant to the anti-proliferative effect of TGF-b. In several types of tumors, particularly those of gastrointestinal origin, resistance to the anti-proliferative effect of TGF-b has been attributed to TGF-b receptor or Smad mutations. However, these mutations are absent from many …

Cell Cycle Regulatory Roles Of Estrogen Receptor Alpha (Erα) In Breast Cancer Cells, Sonia Javanmoghaddam

Dissertations and Theses (Open Access)

Previous studies have shown that Estrogen Receptor alpha (ERα) is an important indicator for diagnosis, prognosis and treatment of breast cancers. However, the question remains as to the role of ERα in the cell in the presence versus absence of 17-β estradiol  In this dissertation the role of ERα in both its unliganded and liganded state, with respect to the cell cycle will be explored.  The cell line models used in this project are ER-positive MCF-7 cells with and without siRNA to ERα and ER-positive MDA-MB-231 cells that have been engineered to express ERα. Cells were synchronized and the cell …

Physician Perceptions Of Risk Regarding Mood Disorders And Pharmacological Management During Pregnancy: What Is Current Practice?, Laura G. Hendon

Dissertations and Theses (Open Access)

Mood disorders are the most common form of mental illness and one of the leading causes of morbidity worldwide.  Major depressive disorder and bipolar disorder have a lifetime prevalence of 16.2% and 4.4%, respectively.  Women comprise a substantial proportion of this population, and an estimated 500,000 pregnancies each year involve women with a psychiatric condition.  Management with psychotropic medications is considered standard of care for most patients with mood disorders.  However, many of these medications are known human teratogens.  Because pregnant women with mood disorders face a high risk of relapse if unmanaged, the obstetrician faces a unique challenge in …

Cell Polarity Regulates Organ Growth Through The Hippo Pathway, Chiao-Lin Chen

Dissertations and Theses (Open Access)

Defects in apical-basal cell polarity and abnormal expression of cell polarity determinants are linked to human cancer. Loss of polarity is highly correlated with malignancy. In Drosophila, perturbation of apical-basal polarity, including overexpressing the apical determinant Crumbs, can lead to uncontrolled tissue growth. Cells mutant for the basolateral determinant scribble overproliferate and can form neoplastic tumors. Interestingly, scribble mutant clones that arise in wild-type tissues are eliminated and therefore do not manifest their tumorigenic potential. However, the mechanisms by which cell polarity coordinates with growth control pathways in developing organs to achieve appropriate organ size remain obscure.

To investigate …

Role Of Vitamin-D3 And Retinoic Acid In A Human Thp-1 Macrophage Model Of Mycobacterium Tuberculosis Infection, Jaymie L. Estrella

Dissertations and Theses (Open Access)

Mycobacterium tuberculosis (Mtb) replicates within the human macrophages and we investigated the activating effects of retinoic acid (RA) and vitamin D3 (VD) on macrophages in relation to the viability of Mtb. A combination of these vitamins (RAVD) enhanced the receptors on THP-1 macrophage (Mannose receptor and DC-SIGN) that increased mycobacterial uptake but inhibited the
subsequent intracellular growth of Mtb by inducing reactive oxygen species (ROS) and autophagy. RAVD also enhanced antigen presenting and homing receptors in THPs that suggested an activated phenotype for THPs following RAVD treatment. RAVD mediated activation was also associated with a marked phenotypic change in Mtb …

Multiple Posttranscriptional Regulatory Features Control Expression Of Ethanolamine Utilization Genes In Enterococcus Faecalis, Kristina A. Fox

Dissertations and Theses (Open Access)

Enterococcus faecalis is a Gram-positive bacterium that lives as a commensal organism in the mammalian gastrointestinal tract, but can behave as an opportunistic pathogen.  Our lab discovered that mutation of the eutK gene attenuates virulence of E. faecalis in the C. elegans model host.  eutK is part of the ethanolamine metabolic pathway which was previously unknown in E. faecalis.  I discovered the presence of two unique posttranscriptional regulatory features that control expression of eut locus genes.  The first feature I found is an AdoCBL riboswitch, a cis-acting RNA regulatory element that acts as a positive regulator of gene …

Gene Discovery In Nonsyndromic Cleft Lip With Or Without Cleft Palate, Brett T. Chiquet

Dissertations and Theses (Open Access)

Nonsyndromic cleft lip with or without cleft palate (NSCLP), a common, complex orofacial birth defect that affects approximately 4,000 newborns each year in the United States, is caused by both genetic and environmental factors. Orofacial clefts affect the mouth and nose, causing severe deformity of the face, which require medical, dental and speech therapies. Despite having substantial genetic liability, less than 25% of the genetic contribute to NSCLP has been identified. The studies described in this thesis were performed to identify genes that contribute to NSCLP and to demonstrate the role of these genes in normal craniofacial development. Using genome …

A Novel Function For Aurora B Kinase In The Regulation Of P53 By Phosphorylation, Chris P. Gully

Dissertations and Theses (Open Access)

The mitotic kinase Aurora B plays a pivotal role in mitosis and cytokinesis and governs the spindle assembly checkpoint which ensures correct chromosome segregation and normal progression through mitosis.  Aurora B is overexpressed in breast and other cancers and may be an important molecular target for chemotherapy.  Tumor suppressor p53 is the guardian of the genome and an important negative regulator of the cell cycle. Previously, it was unknown whether Aurora B and p53 had mutual regulation during the cell cycle.  A small molecule specific inhibitor of Aurora B, AZD1152, gave us an indication that Aurora B negatively impacted p53 …

Regulation Of Set1-Mediated Methylation Of Dam1, John A. Latham

Dissertations and Theses (Open Access)

Eukaryotic genomes exist within a dynamic structure named chromatin in which DNA is wrapped around an octamer of histones forming the nucleosome. Histones are modified by a range of posttranslational modifications including methylation, phosphorylation, and ubiquitination, which are integral to a range of DNA-templated processes including transcriptional regulation. A hallmark for transcriptional activity is methylation of histone H3 on lysine (K) 4 within active gene promoters. In S. cerevisiae, H3K4 methylation is mediated by Set1 within the COMPASS complex. Methylation requires prior ubiquitination of histone H2BK123 by the E2-E3 ligases Rad6 and Bre1, as well as the Paf1 transcriptional …

The Role Of Il-6 In Adenosine-Mediated Pulmonary Fibrosis, Mesias Pedroza

Dissertations and Theses (Open Access)

Adenosine is a purinergic signaling molecule that regulates various aspects of inflammation and has been implicated in the pathogenesis of chronic lung diseases. Previous studies have demonstrated that adenosine up-regulates IL-6 production through the engagement of the A_2B adenosine receptor in various cell types, including alveolar macrophages. IL-6 is elevated in mouse models and humans with chronic lung disease, suggesting a potential role in disease progression. Furthermore, chronic elevation of adenosine in the lungs of adenosine deaminase deficient (Ada^-/-) mice leads to the development of pulmonary inflammation, alveolar destruction, and fibrosis, in conjunction with IL-6 elevation. …

The Role Of Cyclin E In Pkc Iota-Driven Early Ovarian Tumorigenesis, Angela Nanos-Webb

Dissertations and Theses (Open Access)

Among the gynecologic malignancies, epithelial ovarian tumors are the leading cause of death. For the past few decades, the only treatment has involved surgical resection of the tumor and/or general chemotherapies. In an attempt to improve treatment options, we have shown that several oncogenes that are overexpressed in ovarian cancer, PI3K, PKCiota, and cyclin E, all of which have been shown to lead to a poor prognosis and decreased survival, converge into a single pathway that could potentially be targeted therapeutically.

Because of the ability of either PKCiota or cyclin E overexpression to independently induce anchorage-independent growth, a hallmark of …

Prevalence Of Premature Ovarian Failure In Women With Tuberous Sclerosis, Emily Gabitzsch

Dissertations and Theses (Open Access)

Tuberous Sclerosis Complex (TSC) is an autosomal dominant tumor suppressor disorder characterized by hamartomas, or benign growths, in various organ systems. Inactivating mutations in either the TSC1 or the TSC2 gene cause most cases of TSC. Recently, the use of ovarian specific conditional knock-out mouse models has demonstrated a crucial role of the TSC genes in ovarian function. Mice with complete deletion of Tsc1 or Tsc2 showed accelerated ovarian follicle activation and subsequent premature follicular depletion, consistent with the human condition premature ovarian failure (POF). POF is defined in women as the cessation of menses before the age of 40 …

Expression And Regulation Of Human Cytochrome P450 4f Isoforms In Tissue Samples And Under Tnf-Alpha Challenges, Jordan C. Bell

Dissertations and Theses (Open Access)

CYP4F (Cytochrome P4504F) enzymes metabolize endogenous molecules including leukotrienes, prostaglandins and arachidonic acid. The involvement of these endogenous compounds in inflammation has led to the hypothesis that changes in the inflamed tissue environment may affect the expression of CYP4Fs during the pro-inflammatory state, which in turn may modulate inflammatory conditions during the anti-inflammatory state. We demonstrated that inflamed tissues have different levels of CYP4F isoform expression profiles in a number of human samples when compared to the average population. The CYP4F isoform expression levels change with the degree of inflammation present in tissue. Further investigation in cell culture studies revealed …

Immune Modulation Of The Mycobacterium Tuberculosis Granulomatous Response, Kerry J. Welsh

Dissertations and Theses (Open Access)

Tuberculosis (TB) remains a major public health burden. The immunocompetant host responds to Mycobacterium tuberculosis (MTB) infection by the formation of granulomas, which initially prevent uncontrolled bacterial proliferation and dissemination. However, increasing evidence suggests that granuloma formation promotes persistence of the organism by physically separating infected cells from effector lymphocytes and by inducing a state of non-replicating persistence in the bacilli, making them resistant to the action of antibiotics. Additionally, immune-mediated tissue destruction likely facilitates disease transmission. The granulomatous response is in part due to mycobacterial glycolipid antigens. Therefore, studies were first undertaken to determine the innate mechanisms of mycobacterial …

Molecular Mechanisms Underlying The Transcriptional Regulation Of T Helper 17 And Regulatory T Cells, Gustavo Javier Martinez

Dissertations and Theses (Open Access)

CD4⁺ T helper (Th) lymphocytes are vital for integrating immune responses by orchestrating the function of other immune cell types. Naïve Th cells can differentiate into different effector subsets that are characterized by their cytokine profile and immune regulatory functions. These subsets include Th1, Th2, Th17, natural and inducible regulatory T cells (nTreg and iTreg respectively), among others. We focused our investigation on two Th lineages, Th17 and regulatory T cells, with opposing functions in the immune system. These subsets have been suggested to be reciprocally regulated since they both require TGF-b for their development. We investigated the role …

Comparison Of Clinical Knowledge Management Capabilities Of Commercially-Available And Leading Internally-Developed Electronic Health Records, Dean F Sittig, Adam Wright, Seth Meltzer, Linas Simonaitis, R Scott Evans, W Paul Nichol, Joan S Ash, Blackford Middleton

Faculty, Staff and Student Publications

BACKGROUND: We have carried out an extensive qualitative research program focused on the barriers and facilitators to successful adoption and use of various features of advanced, state-of-the-art electronic health records (EHRs) within large, academic, teaching facilities with long-standing EHR research and development programs. We have recently begun investigating smaller, community hospitals and out-patient clinics that rely on commercially-available EHRs. We sought to assess whether the current generation of commercially-available EHRs are capable of providing the clinical knowledge management features, functions, tools, and techniques required to deliver and maintain the clinical decision support (CDS) interventions required to support the recently defined …