Life Sciences Commons^™

Providing Experimental Evidence For Mouse Telomerase Reverse Transcriptase As A Novel And Unique Adult Neural Stem Cell Marker, Caroline Dean Curtis

Electronic Theses and Dissertations

With the prevalence of neurodegenerative pathologies in our society today it is imperative that we begin to look at novel approaches to the underlying problem of dying neurons that are not replaced. Adult neural stem cells exist naturally and could potentially be manipulated into targeted repair of damaged brains, given substantial research. The first step in this process is to find a way to specifically mark the earliest subset of these cells, the quiescent adult neural stem cells. Here we provide evidence for the existence of a novel and unique qANSC marker in mouse telomerase reverse transcriptase (mTERT). mTERT has …

Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush

Electronic Theses and Dissertations

There are thirteen known endogenous EGF-like ligands. We previously reported that Betacellulin (BTC) increases ligand-mediated corneal wound healing more than Epidermal Growth Factor (EGF) [Peterson et al. (2014) IOVS 55(5):2870-80], although the molecular reason for this is unknown. Despite being better at promoting wound healing via enhanced cell migration, BTC has reduced receptor affinity and weaker induction of EGFR phosphorylation. These data indicate that BTC’s response is not due to enhanced affinity or EGFR-kinase activity. Receptor phosphorylation and proximity ligation assays indicate that BTC treatment significantly increases ErbB3 phosphorylation and EGFR:ErbB3 heterodimers. BTC traffics EGFR at a faster rate than …

The Effect Of Wild Blueberry Bioactives On Endothelial Cell Migration And Angiogenesis: An In Vitro Mechanistic, Genomic And Proteomic Approach, Panagiotis Tsakiroglou

Electronic Theses and Dissertations

The goal of this study is to investigate the effects of wild blueberry fractions (Anthocyanins and Phenolic acids) on vascular function and physiology. More specifically the potential effects of the above fractions and their combination in physiological concentrations on endothelial cell migration, angiogenesis, gene expression and proteins synthesis of markers related to the above processes. The objectives are to study whether anthocyanins, phenolic acids and their combinations (ACNs:PAs) affect: a) cell proliferation, b) speed of endothelial cell migration, c) angiogenesis, d) gene expression of genes critical for cell migration and angiogenesis such as RAC1, RHOA, AKT1, eNOS and VEGF and …

Characterization Of Phosphorylated G Protein Function And Membrane Culstering By Super Resolution Imaging, Sarah A. Alamer

Electronic Theses and Dissertations

Heterotrimeric G proteins play crucial roles in various signal transduction pathways, where they act as molecular switches in transducing a signal from G protein coupled receptors (GPCRs) at the plasma membrane to downstream effectors. Although their mechanism of action is mostly concentrated at the plasma membrane, their dynamic membrane organization and how it is regulated are not understood. Due to the diffraction limited resolution of fluorescence microscopy, studying the precise organization of membrane proteins can be challenging. In this study, we took advantage of super-resolution fluorescence photoactivation localization microscopy (FPALM) to overcome this challenge. Dictyostelium discoideum was used as a …

Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich

Electronic Theses and Dissertations

Arsenic is a metalloid that contaminates drinking water supplies worldwide. Due to concerns for human health, the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) have established a safe level in drinking water of ≤ 10 ppb. Arsenic has been shown to have carcinogenic effects in humans at high and low doses. Chronic exposure may result in dermal conditions such as hyperkeratosis and hyperpigmentation. Recently, arsenic exposure has also been linked to lower IQ values in children. The effect of arsenic on neurogenesis, specifically eye development, has not been widely explored. This study aimed to examine the …

Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle

Electronic Theses and Dissertations

Background: Human arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic metabolizing enzyme found in almost all tissues. NAT1 can additionally hydrolyze acetyl-coenzyme A (acetyl-CoA) in the absence of an arylamine substrate. NAT1 expression varies inter-individually and is elevated in several cancers including estrogen receptor positive (ER+) breast cancers. Additionally, multiple studies have shown the knockdown of NAT1, by both small molecule inhibition and siRNA methods, in breast cancer cells leads to decreased invasive ability and proliferation and decreased anchorage-independent colony formation. However, the exact mechanism by which NAT1 expression affects cancer risk and progression remains unclear. Additionally, consequences …

Egfr Signaling From The Early Endosome., Julie A. Gosney

Electronic Theses and Dissertations

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is an integral component of proliferative signaling. When activated by a ligand at the plasma membrane, EGFR dimerizes with another ErbB family receptor, leading to kinase domain activation and transphosphorylation of C-terminus tyrosine residues. These phosphotyrosines act as crucial regulators of EGFR signaling as effector proteins dock to the receptor at these sites. The receptor undergoes clathrin-mediated endocytosis into early endosomes, where it can then be trafficked to a lysosome for degradation. However, the kinase domain of EGFR retains its activity during trafficking, suggesting that EGFR can continue …

Unfolded Protein Response Pathways In Skeletal Muscle Homeostasis., Kyle R. Bohnert

Electronic Theses and Dissertations

Skeletal muscle mass, contractile properties, and metabolic function are regulated through the coordinated activation of multiple intracellular signaling pathways and genetic reprogramming. The endoplasmic reticulum (ER) plays a pivotal role in protein folding and calcium homeostasis in many cell types, including skeletal muscle. Disruption of calcium levels or accumulation of misfolded proteins in the ER lumen leads to stress, which results in the activation of a signaling network called the unfolded protein response (UPR). Further, recent studies have suggested that in certain conditions, UPR pathways can be activated independent of ER stress. However, the role of ER stress and the …

Pi3k/Akt Signaling Activates Hsf1 To Preserve Proteostasis And Sustain Growth, Zijian Tang

Electronic Theses and Dissertations

Signaling through oncogenic PI3K/AKT kinase pathway is crucial to cell and organ growth. Phosphorylation by AKT has long been perceived as a key factor to enhance protein biosynthesis that enables cell growth and survival. Here, we report that HSF1, the master regulator of the proteotoxic stress response (PSR), is a new AKT substrate. Beyond mobilizing the PSR under heat shock, the AKT-mediated HSF1 activation supports robust growth. In a mouse model of human megalencephaly, expression of a constitutively active PI3KCAsuffices to drive brain overgrowth, and strikingly, it also provokes proteomic chaos including protein aggregation and amyloidogenesis. Deletion of Hsf1 …

Tarbp2 -Mediated Post-Transcriptional Regulation Of Gene Expression During Murine Embryonic Development And Spermatogenesis, Sri Ramulu N. Pullagura

Electronic Theses and Dissertations

Micro RNAs (miRNAs), which are ~22 nucleotide (nt) long RNA molecules and several RNA binding proteins (RBPs) engage in an RNA dependent post-transcriptional gene silencing process known as RNA interference (RNAi). In the canonical miRNA biogenesis pathway, an enzyme known as DICER cleaves the ~70nt pre-miRNA to a ~22nt long miRNA that is loaded into the RNAi effector mechanism, the RNA induced silencing complex (RISC).

Several in vitro studies provide suggestive evidence that mammalian double stranded RNA binding proteins (dsRBPs), such as TARBP2, act as DICER cofactors in miRNA processing and RISC loading to promote RNAi activity. A screen attempting …

Deciphering The Role Of Adrenergic Hormones In Embryonic Cardiac Calcium Signaling And Metabolism, Jessica Peoples

Electronic Theses and Dissertations

The adrenergic hormones norepinephrine (NE) and epinephrine (EPI) are critical regulators of mammalian cardiovascular physiology. NE and EPI mediate stress responses to enhance cardiovascular function, however dysregulation of adrenergic signaling leads to heart failure, congenital heart malformations, and sudden cardiac death. Adrenergic hormone-expressing cells were found in the early embryonic heart, and NE has been determined essential for embryonic cardiac development. Despite extensive work in adults, the regulatory roles and adrenergic targets of these hormones during embryonic cardiac development have not yet been fully determined. Prior transcriptomic studies from our lab showed that expression of signal transduction and metabolic genes …

Mechanisms By Which Mechanotransduction Promotes Proliferation In Keratinocytes, Chhavi Chaudhary

Electronic Theses and Dissertations

Chronic wounds are wounds that do not heal within 30 days and often they can last over a year. Interference in any of the wound healing stages may hinder the process. Some of the local and systemic factors such as infection, old age, diabetes, AIDS, and the regular application of corticoids may also have negative effects on the healing process. Cell proliferation is an important phase in epidermal wound healing in which surviving epithelial cells replicate independently into daughter cells through mitosis and maintain a balance between cell growth and cell loss during the cell cycle. Physical and chemical stimuli …

Identification Of Macropinocytosis Regulating Proteins And Signaling From Macropinosomes, Louise Monga

Electronic Theses and Dissertations

Understanding macrophage cell biology is important due to macrophages key roles in human health and diseases including proper immune function, wound healing, atherosclerosis, and cancer. Despite their importance, relatively little is understood about macrophage activation, growth factor signaling, and cytoskeletal regulation. This thesis presents data from investigations into mechanisms of macrophage growth factor signaling and actin polymerization for ruffling and macropinocytosis. Alt-R CRISPR-Cas9 method and dextran uptake assay were used to knock out individual genes (SHP-1, Lyn, Syk, BTK, Vav1) and determine their role in macropinocytosis and CSF-1R signaling. Dextran uptake was disrupted in SHP-1 and Lyn targeted knockout cells, …

Origins Of Animal Cell Adhesion, Jennyfer Mora Mitchell

Electronic Theses and Dissertations

A fundamental requirement for multicellularity is cell adhesion. This includes mechanisms by which cells adhere to each other and to their secreted extracellular matrix (ECM). Two well characterized adhesion complexes in animals include: 1) adherens junctions (AJs), which are involved in cell-cell adhesion and composed of cadherin receptors, p120-, α- and β-catenin, and 2) focal adhesions (FAs), which are involved in cell-ECM adhesion and include proteins such as integrins, vinculin, paxillin, talin and focal adhesion kinase (FAK). The molecular components of AJs are widely conserved in animals, and largely absent in non-animals. In contrast, the molecular components of FAs have …

Superresolved Three-Dimensional Analysis Of The Spatial Arrangement Of The Human Immunodeficiency Virus Type-1 (Hiv-1) Envelope Glycoprotein At Sites Of Viral Assembly, Carmen Anne Buttler

Electronic Theses and Dissertations

Human Immunodeficiency Virus type 1 (HIV-1) replicates by forcing infected host cells to produce new virus particles, which assemble form protein components on the inner leaflet of the host cell's plasma membrane. This involves incorporation of the essential viral envelope glycoprotein (Env) into a structural lattice of viral Gag proteins. The mechanism of Env recruitment and incorporation is not well understood. To better define this process, we seek to describe the timing of Env-Gag encounters during particle assembly by measuring angular positions of Env proteins about the surfaces of budding particles. Using three-dimensional superresolution microscopy, we show that Env distributions …

Evaluating The Interaction Between The Human Melanocortin-2 Receptor And The Accessory Protein, Mrap1: Chimeric Receptor And Alanine Substitution Studies On Transmembrane Domain 4, Extracellular Loop 2, And Transmembrane Domain 5, Perry Victoria Davis

Electronic Theses and Dissertations

The melanocortin-2 receptor (MC2R) is the most complex due to its trafficking and ligand selectivity requirements for proper activation. The MC2R requires the melanocortin receptor accessory protein-1 (MRAP1) for proper trafficking and activation of the receptor by the melanocortin hormone, ACTH. MRAP1 is a single transmembrane-spanning domain protein that creates a homodimer with another MRAP1 protein. Furthermore, MRAP2 creates a heterodimer with the MC2R. Previous studies have shown that the MRAP1 protein contains an activation motif required for activation of MC2R and this activation motif located on the extracellular space side of the plasma membrane of the cell. The objective …

The Identification And Segmentation Of Astrocytoma Prior To Critical Mass, By Means Of A Volumetric/Subregion Regression Analysis Of Normal And Neoplastic Brain Tissue, Lyn Higgins

Electronic Theses and Dissertations

As the underlying cause of Glioblastoma Multiforme (GBM) is presently unclear, this research implements a new approach to identifying and segmenting plausible instances of GBM prior to critical mass. Grade-IV Astrocytoma, or GBM, is an aggressive and malignant cancer arising from star-shaped glial cells, or astrocytes, where the astrocytes, functionally, assist in the support and protection of neurons within the central nervous system and spinal cord. Subsequently, our motivation for researching the ability to recognize GBM is that the underlying cause of the mutation is presently unclear, leading to the operative that GBM is only detectable through a combination of …

Environmental And Physiological Regulation Of Yellow Stingray Color Change, Theresa Rose Gunn

Electronic Theses and Dissertations

Many reef fishes exhibit dynamic coloration and body patterns that can change under nervous or hormonal control. Several species of benthic sharks and rays likely alter melanin in the skin to provide background matching for camouflage. The yellow stingray (Urobatis jamaicensis) is a benthically-oriented elasmobranch with elaborate spot patterns that provide effective camouflage within its habitats. This patterning, when coupled with the ability to alter melanin in response to background color, could increase background matching effectiveness in these species. The yellow stingray has been anecdotally noted to lighten or darken skin color.However, it is unclear whether this type …