Medicine and Health Sciences Commons^™

Regulation Of Cancer Metastasis By Protein Kinase D1: A Global Regulatory Cascade, Aditya Ganju

Theses and Dissertations (ETD)

Protein Kinase D1 (PKD1) is a serine threonine kinase which is downregulated in Prostate, Breast and Colon Cancer. It functions as a tumor suppressor in different cancer cells. Downregulation of PKD1 is known to be associated with aggressiveness of the cancer. PKD1 is known to regulate many key oncogenic signaling pathways such as E-cadherin, β-catenin and Androgen Receptor signaling pathways. Aberrant expression of these oncogenic pathways leads to transformation of cells from normal to malignant phenotype, thereby leading to increased proliferation, growth and metastasis to distant organs of these cancer cells. Literature evidence also points to the fact that E-cadherin …

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

Theses and Dissertations (ETD)

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

Dissecting The Physiological Roles Of Ulk1/2 In The Mouse Brain, Bo Wang

Theses and Dissertations (ETD)

Mammalian UNC-51–like kinases 1 and 2 (ULK1 and ULK2), Caenorhabditis elegans UNC-51 and Drosophila melanogaster Atg1 are redundant serine/threonine kinases that regulate flux through the autophagy pathway in response to various types of cellular stress. C. elegans UNC-51 and D. melanogaster Atg1 also promote axonal growth and defasciculation, and disruption of these genes results in defects in axon guidance in invertebrates. Germline Ulk1/2-deficient mice die perinatally. Therefore, we used a conditional-knockout approach to investigate the roles of ULK1/2 in the brain. Mice lacking Ulk1 and Ulk2 in their central nervous systems (CNS) showed defects in axonal pathfinding and defasciculation affecting …

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

Theses and Dissertations (ETD)

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

Environmental Signaling Through The Target Of Rapamycin Complex 1 (Torc1) And The Regulation Of Epigenetic Mechanisms, Jason J. Workman

Theses and Dissertations (ETD)

The gene expression profile of a eukaryotic cell is responsive to a variety of extracellular stimuli, including nutrient availability, which allows cells to toggle between anabolism and catabolism based on the favorability of their environment. Much of this information is relayed through signaling complexes, such as the target of rapamycin complex 1 (TORC1), to downstream chromatin modifying enzymes. These enzymes impact the gene regulatory process through altered histone post-translation modifications, changes in chromatin structure, and docking of chromatin regulatory complexes. Yet, despite preliminary studies suggesting that TORC1 affects epigenetic mechanisms, including histone H3 lysine 56 acetylation (H3K56ac), almost nothing is …

Role Of Occludin In The Regulation Of Epithelial Tight Junctions, Bhargavi Manda

Theses and Dissertations (ETD)

Tight junctions (TJ) constitute the primary component of epithelial barrier function, a disruption of which is involved in the pathogenesis of many gastrointestinal, pulmonary and renal diseases. Occludin is the major transmembrane protein of TJ, a deletion of which leads to a complex phenotype including chronic inflammation in several epithelial tissues of occludin deficient mice and poor TJ integrity in epithelial cell lines. Its down regulation was seen in Crohn’s disease, tumors of the colon, brain, endometrium and breast cancer. Occludin is also known to be a target that enables Hepatitis C Virus infection and bacterial pathogenesis. But the specific …

Multipronged Approach To Study Glaucoma-Associated Phenotypes, Sumana Rameshbabu Chintalapudi

Theses and Dissertations (ETD)

Glaucoma refers to a group of conditions characterized by death of RGCs, increase in intraocular pressure is usually a precursor to glaucoma and irreversible optic neuropathy leads to visual impairment and blindness. Recent advances have seen a surge of new ideas and technologies to aid in the early detection, efficacious treatments and neuroprotection. Despite advances we face several challenges in understanding the pathophysiology of glaucoma. One of the many challenges scientists and ophthalmologists are facing is, to better understand IOP, its role in glaucomatous damage and design safer, more predictable IOP-lowering therapies. Another challenge is to find a practical method …

Neuroanatomical Maps And Taste Reactivity To Sweet, Umami, And Bitter Taste In The Pbn Of C57bl/6j Mice, Jennifer Marie Saputra

Theses and Dissertations (ETD)

Humans can distinguish at least five different taste qualities, sour, salty, bitter, sweet, and umami (the savory taste of certain amino acids). In neuroscience research, behavioral testing is used to measure the ability of rodents (including inbred mice) to discriminate between the different taste qualities. Taste reactivity and two-bottle preference are behavioral tests that are utilized to investigate different aspects of taste. These tests involve either voluntary or forced consumption of taste stimuli, respectively. Either test can be used to infer the preference and palatability of the stimulus consumed by an animal.

In order to understand the basis of taste …

Evaluating The Therapeutic Effect Of An Hsp90 Inhibitor In Mouse Models Of Alzheimer’S Disease, Bin Wang

Theses and Dissertations (ETD)

The excessive accumulation of amyloid peptides (Aβ) represents one major pathological hallmark of Alzheimer’s disease (AD), which is most notably characterized by synaptic dysfunction. Strategies targeting heat shock protein 90 (Hsp90) inhibition have been widely investigated in the treatment of cancer for over two decades. Its application in the treatment of neurodegenerative diseases however, has emerged more recently in the last decade. The role of the Hsp90 chaperone in clearing misfolded protein aggregates has been well established (in vitro only), but its function in synaptic activity remains elusive.

In our study, we utilized a widely used Hsp90 inhibitor, 17-AAG …

The Roles Of Nuclear Receptor Nr4a1 In Cancer Cell Proliferation And Skeletal Muscle Differentiation, Alexa Farmer

Theses and Dissertations (ETD)

Nuclear receptors (NRs) constitute a major class of drug targets in the treatment of various cancer types. NRs respond to cellular signals and become activated upon ligand binding to transcriptionally modulate expression of target genes. NR4A1 (Nur77) is a member of the NR4A family of nuclear receptors and displays an oncogenic profile in many cancer models. It is often upregulated in adult solid malignancies and is known to promote cell proliferation and survival. Knockdown studies of NR4A1 in cancer cell lines results in decreased cell growth and angiogenesis and increased apoptosis, suggesting NR4A1 is an oncogenic protein. Due to the …

Repeated Zolpidem Treatment Effects On Sedative Tolerance, Withdrawal, Mrna Levels, And Protein Expression, Brittany T. Wright

Theses and Dissertations (ETD)

Zolpidem and benzodiazepines (BZs) potentiate the inhibitory action of gamma-Aminobutyric acid (GABA) by allosterically binding to GABAA receptors (GABAAR). Prolonged use of GABAAR positive allosteric modulators (PAM) can lead to behavioral tolerance, the diminished response to the same drug dose with repeated use, and withdrawal, a group of symptoms that occur due to abrupt end of drug treatment. Zolpidem is a short-acting, non-BZ GABAAR PAM whose potential for tolerance and withdrawal is unclear. Zolpidem demonstrates sedative efficacy similar to BZs and has become a main treatment of insomnia in lieu of BZs. Zolpidem replaced BZs due to lower incidences of …

Investigating The Regulation And Function Of The Nr4a Nuclear Receptors In Cancer, Jordan A. Beard

Theses and Dissertations (ETD)

The nuclear receptor (NR) superfamily represents a structurally-conserved group of ligand-regulated transcription factors. These proteins have critical roles in various physiological and pathological processes, including cancer, and have been targets of drug therapy. The orphan NR subfamily 4A (NR4A), which includes the NR4A1 (Nur77), NR4A2 (Nurr1), and NR4A3 (Nor-1) genes, has been implicated in adult solid tumors and has been characterized as pro-tumorigenic mediator of cell proliferation, transformation, migration, and drug resistance. Alternatively, in leukemia, NR4A1 and NR4A3 have been described as tumor suppressors in hematologic malignancies. Members of the NR4A family are commonly overexpressed in cancer and this has …

Examining The Roles Of Gabaa Receptor Subtypes In Anxiety And Anxiolysis: Focusing On The Basolateral Amygdala, Yudong Gao

Theses and Dissertations (ETD)

The investigation of the differential roles GABA_A receptor (GABA_AR) subtypes play in mediating various behaviors such as fear and anxiety was an intriguing research topic over the past decade. At present, most evidence suggests that benzodiazepine (BZ)-induced anxiolysis is primarily mediated by GABA_ARs containing the α2-subunit (α2-subtype). However, there is conflicting evidence as to whether α1- and α3-subtypes might also be involved in BZ-induced anxiolysis. In an attempt to further discern the role played by different α-subtype GABA_ARs in BZ-induced anxiolysis both systemically and within the basolateral amygdala (BLA), a brain region crucial …

Interaction Between Two E3 Ligases, Nedd8ylated Cullin And Hhari, Kheewoong Baek

Theses and Dissertations (ETD)

RBR (RING1-in between RING-RING2) is a special type of E3 ubiquitin ligase containing three zinc-binding RING (Really Interesting New Gene) domains, while adopting mechanisms of HECT (Homologous to E6-AP Carboxyl Terminus) for substrate ubiquitination. Most well known RBRs include Parkin and HOIP, which are associated with Parkinson’s disease and innate immune deficiency. However, it is not well known how the RBR proteins gain activity, as they are known to be autoinhibited. Here I show that a specific F430A, E431A, E503A triple mutation of RBR protein HHARI (Human homologue of Ariadne) and its interaction with NEDD8ylated cullin RING ligase can both …

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

Theses and Dissertations (ETD)

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

Regulation Of Irf-3-Dependent Innate Immune Signaling Pathway By The Plpro Domain Of Non-Structural Protein 3 (Nsp3) Of Severe Acute Respiratory Syndrome (Sars) Coronavirus, Sandra Nicole Lester

Theses and Dissertations (ETD)

The induction of Type I Interferons (IFNs) is a powerful and rapid innate defense mechanism against viral infection, and many viruses have developed elaborate strategies to overcome the antiviral effects of IFN, ensuring their survival and replication. Severe acute respiratory syndrome coronavirus (SARS-CoV) is a highly pathogenic virus that causes severe lung disease in humans and is associated with high mortality rates. SARS-CoV, like all other successful viruses, encode proteins that counteract the innate immune response. A number of reports have indicated the papain-like protease (PLpro) domain of SARS-CoV Non-Structural Protein 3 (NSP3) as a powerful interferon antagonist, by suppressing …

Novel Oncogenic Drivers In Pediatric Gliomagenesis, Alexander K. Diaz

Theses and Dissertations (ETD)

Pediatric high-grade gliomas (pHGGs), with a two-year survival rate of less than 20%, are some of the most aggressive human cancers. This dissertation begins with our analysis of 127 pHGGs, including brainstem (BS) and non-brainstem (NBS) tumors, from 118 patients using next-generation sequencing technologies. Nearly one-third of BS-HGGs, also known as diffuse intrinsic pontine gliomas (DIPGs), harbored somatic heterozygous missense mutations in ACVR1, coding for a receptor serine-threonine kinase involved in bone morphogenetic protein (BMP) signaling. These alterations led to gain-of-function as evidenced by increased phosphorylation of downstream targets in primary astrocytes and zebrafish embryo ventralization. Whole-genome sequencing and …

Mild Traumatic Brain Injury With Associated Visual System Dysfunction: Investigating Histopathology, Functional Correlates, And A Novel Therapeutic Immune Modulator, Natalie M. Guley

Theses and Dissertations (ETD)

Background. Traumatic brain injury (TBI) is a significant source of morbidity and mortality worldwide. Injuries associated with moderate to severe TBI can be profound, and have historically overshadowed the significant impact mild TBI (mTBI) can have on the lives of affected individuals. Mild TBI can manifest in a number of different ways, but one of the most significant and often debilitating is its impact on the visual system. In order to further investigate the underlying pathology of mTBI and test potential therapeutics, we developed a mouse model of mTBI induced by blast overpressure. In this model, a 50-60 psi …

Hit Identification For Pkcζ Inhibitors: Structure-Based Optimization, Virtual Screening, And Biological Evaluation, Xiaoxin Wu

Theses and Dissertations (ETD)

Protein kinase C ζ (PKCζ) is believed to be a promising target for the treatment of some diseases, including inflammatory diseases, obesity and diabetes. Hit identification of PKCζ inhibitors was conducted by structure-based modification, virtual screening and biological evaluation. Among all the compounds selected and synthesized, compound JW-1-60A showed moderate activity against PKCζ at 30 μM and 100 μM. The molecular modeling studies showed that the binding mode of JW-1-61A was very close to the binding mode of JP-3-149, a reported PKCζ inhibitor with very potent activity, which might partially explain the moderate activity of JW-1-61A. Based on the structure …

Understanding Structural And Functional Mechanisms Of Emi1 Inhibition Of The Anaphase Promoting Complex, Edmond Randall Watson

Theses and Dissertations (ETD)

Healthy, reproducing cells create and destroy proteins in an ordered manner. Both the concentration and localization of protein pools is important to regulate the many cellular processes necessary for the life of the cell. In order to produce new proteins, cells degrade existing materials such as proteins and organelles that are dispensable or troublesome in order to recycle their raw components. Degradation is accomplished largely through two major pathways: in bulk through processes such as autophagy and phagocytosis, or in a targeted manner through the ubiquitin-proteasome pathway. Autophagy utilizes an encompassing body to encapsulate targets and surrounding materials for decomposition …

The Role Of Drak2 In T Cell Function And Autoimmunity, Tarsha L. Harris

Theses and Dissertations (ETD)

The immune system utilizes many regulatory mechanisms to limit immune responses and ensure that immune cells target foreign pathogens and not healthy cells of the body. However, some immune cells can escape these checkpoints and attack the body’s healthy cells, leading to tissue destruction and devastating autoimmune disorders. For example, multiple sclerosis (MS) occurs when immune cells attack the myelin sheath surrounding neurons of the central nervous system (CNS). Likewise, the destruction of pancreatic islet cells by dysregulated immune cells leads to type 1 diabetes (T1D). Remarkably, there are more than 80 types of autoimmune diseases. An estimated 50 million …

Antibodies To Heterogenous Nuclear Ribonucleoprotein A1 Penetrate Neurons Leading To Multiple Downstream Effects Resulting In Neurodegeneration, Joshua Nathan Douglas

Theses and Dissertations (ETD)

Multiple sclerosis (MS) is the most common demyelinating disorder of the central nervous system. MS is believed to occur in genetically susceptible individuals due to an unknown environmental stimulus. MS patients produce autoantibodies to heterogenous nuclear ribonuclearprotein A1 (hnRNP A1), an RNA binding protein (RBP) highly expressed in neurons. hnRNP A1 functions in pre-mRNA splicing, mRNA trafficking, and translation. Furthermore, the anti-hnRNP A1 antibodies are specific to a N-terminal region termed ‘M9’ which serves as a nuclear export sequence/nuclear localization sequence (NES/NLS) responsible for nuclear/cytoplasmic transport of the protein. In this manuscript we will provide data revealing that anti-hnRNP A1 …

Dissecting The Novel Roles Of Trim56 In Antiviral Innate Immunity, Baoming Liu

Theses and Dissertations (ETD)

The tripartite motif-containing (TRIM) proteins have emerged as a new class of host antiviral restriction factors, with several demonstrating roles in regulating innate antiviral responses. Of >70 known TRIMs, TRIM56 inhibits replication of bovine viral diarrhea virus, a ruminant pestivirus of the family Flaviviridae, but has no appreciable effect on VSV, a rhabdovirus. We have also shown that TRIM56 forms a complex with the Toll-like receptor-3 (TLR3) adaptor, TRIF, via its C-terminal residues 621-750, and augments TLR3-mediated interferon (IFN) induction and establishment of an antiviral state. Yet, TRIM56’s antiviral spectrum and the precise underlying mechanisms by which TRIM56 executes …