Cell Biology Commons^™

Dna Damage Response Activates The Electron Transport Chain And Oxidative Metabolism By Two Parallel Mechanisms, Shreya Nagar

Theses and Dissertations

The DNA damage response (DDR) is an evolutionarily conserved process essential for cell survival. Major part of DDR is coordinated by DNA damage checkpoint (DDC). In addition to DDC, eukaryotic cells also have DNA replication checkpoint (DRC) that is distinct from the DDC and specifically signals slowly progressing or arrested replication forks. DDR involves stalling or arrest of the cell cycle, initiation of DNA repair, and altered regulation of transcription, translation, and the ubiquitin-proteasome system. DDR also triggers transcription shut-off of histone genes. One of the key outcomes of DDC/DRC activation is the increased synthesis of the deoxyribonucleoside triphosphates (dNTPs), …

Tgif1 Physiological Levels Limit Β-Cell Distress And Neonatal Diabetes, Creighton J. Friend

Theses and Dissertations

TGIF1 belongs to the superfamily of homeodomain proteins, which regulate a wide variety of biological functions, including cell stemness and specification of cell fate during early development. Perhaps surprisingly, we found that enforced expression in pancreatic progenitor cells during embryogenesis resulted in severe diabetes, hinting at the possibility that TGIF1 might regulate pancreas development. Subsequent genetic experiments targeting β-cells showed that TGIF1 affected β-cell function and homeostasis. Transcriptomic analysis revealed that TGIF1 expression inhibits the expression of essential components of UPR signaling, underscoring a potential mechanism in which TGIF1 disrupts protein folding and secretion. Congruently, TGIF1 expression led to a …

Nup211 Plays An Important Role In Regulating Mrna Export And Stress Response, Ayana Ikenouchi

Theses and Dissertations

Nup211 is a nuclear pore basket component in Schizosaccharomyces pombe and roles in the gating functions of NPCs. Using RT-qPCR, I found that in nup211-shutoff cells, the transcript levels of genes in mRNA export and stress-response pathways were significantly changed, suggesting nup211 is involved in regulating stress response pathways.

Characterization Of The Responses To Chronic Stress In Caenorhabditis Elegans, Amy Laura Knight

Theses and Dissertations

Exposure to chronic temperature stress influences organismal phenotypes that are important for human health, agriculture, and ecology. In this thesis, the model organism Caenorhabditis elegans was used to study the effects of temperature stress on reproduction and lifespan. It was found that worms demonstrated a rapid shut down in egg-laying between 18-24 hours of exposure to 28°C. Despite this reproductive defect, the overall lifespan of worms was unaffected. At the molecular level, heat shock factor 1 (HSF-1), a regulator of the protective molecular pathway known as the heat shock response (HSR), was identified as important for progeny production during heat …

Development Of New Treatments For Asthma And Neuropathic Pain Based On Ɣ-Aminobutyric Acid A Receptor (Gabaar) Ligands, Nicolas Mark Zahn

Theses and Dissertations

The γ-aminobutyric acid A receptor (GABAAR) is a ligand-gated pentameric chloride channel consisting of several identified subunits: α1-6, β1-3, γ1-3, δ, ε, π, θ, ρ1-3.1-2 Typical arrangement of subunits consists of two α subunits, two β subunits, and one γ subunit.3 GABAARs have two binding sites for the endogenous ligand γ-aminobutyric acid (GABA), between the α and β subunits. GABAARs also have a binding site for positive allosteric modulators, such as benzodiazepines, between the α and γ subunits.4-5 Due to their ability to treat anxiety, epilepsy, insomnia, and muscle relaxation, benzodiazepines are widely prescribed pharmaceuticals.6-7 Still, adverse effects result from …

Identifying The Human Homologs Of Yeast Rab Proteins Ypt10 & Ypt11 And A Global-Scale Louse Endosymbiont Genome Variation, Nathaniel P. Smith

Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is a late-onset fatal neurodegenerative disease that causes loss of upper and/or lower motor neurons, and currently has no treatment or cure available. Over 90% of cases occur spontaneously with unknown causes, highlighting the complexity of the disease, and only 10% of cases are linked to heritable genetic mutations. Numerous ALS-linked genes are conserved through evolution, and model organisms may therefore provide opportunities to understand disease pathology at a molecular or cellular level, proving instrumental in identifying therapeutic targets. ALS subtype 8 (ALS8) is caused by an autosomal dominant P56S mutation in the VAPB gene that …

Evaluating The Biological Activities Of Novel Histone Deacetylase Inhibitors (Hdaci) In Adherent And Nonadherent Tumor Cell Lines, Samer Alanani

Theses and Dissertations

Epigenetic dysregulations are linked to many human diseases including neurodegenerative disorders, immunodeficiencies, cardiac disease, and most notably cancer. Changes in the mechanisms of histone modifications have been recognized as hallmarks of carcinogenesis. One of these modifications is histone acetylation which is regulated by the activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). The reversible actions of these enzymes govern the acetylome and maintain its balance allowing for activation and repression of gene transcription. However, aberrant overexpression of HDACs in certain tumors is associated with decreased levels of transcription leading to tumor progression and survival. Hence, small-molecule histone deacetylase inhibitors …

Negative Regulation Of The Kinase Lin-45 By The E3/E4 Ubiquitin Ligase Ufd-2, Augustin Deniaud

Theses and Dissertations

The serine/threonine kinase BRAF is a key part of the Ras-Raf-MEK-ERK pathway, an inducer of cell growth, differentiation, and survival. In humans, activating mutations, most commonly BRAF(V600E), have been detected in several cancers, including melanoma and thyroid cancer. In the Caenorhabditis elegans ortholog LIN-45, the equivalent mutation LIN-45(V627E) results in elevated Raf-MEK-ERK signaling. We performed an unbiased genetic screen to identify negative regulators of LIN-45(V627E). Here, we report the identification of the E3/E4 ubiquitin ligase UFD-2, and show it is a negative regulator of LIN-45 protein activity and levels. Loss of UFD-2 leads to accumulation of wild-type LIN-45 protein as …

Divergent Regulatory Roles Of Nurd Chromatin Remodeling Complex Subunits Gatad2 And Chd4 In Caenorhabditis Elegans, Nicole Lynn Golden

Theses and Dissertations

During stress, a protective cellular network known as the heat shock response (HSR) is induced to maintain protein-folding homeostasis, or proteostasis. While the HSR is essential for stress resistance, its misregulation is associated with neurodegenerative disease and cancer. Using the nematode model organism Caenorhabditis elegans, we have identified the chromatin remodeling complex NuRD (nucleosome remodeling and deacetylase) as a novel regulator of the HSR. Here, we begin with a brief introduction of the HSR and chromatin remodeling complexes in C. elegans, prior to presenting our findings in a series of two chapters. In chapter one, we outline a set of …

Distinct Spatiotemporal Regulation Of The Cytoprotective Heat Shock Response In Caenorhabditis Elegans, Rosemary Nadine Plagens

Theses and Dissertations

Every organism studied to-date utilizes the heat shock response (HSR) to maintain protein-folding homeostasis (proteostasis) during temperature or other protein-folding stress. The HSR has been well characterized using acute heat stress (HS) in single-celled models, but less is known about how distinct cell types and tissues respond to HS. Furthermore, how metazoans respond to prolonged HS at the molecular level remains relatively unexplored. The model organism C. elegans, with its genetic tractability and distinct tissues and behaviors, has been used extensively in the field to characterize the acute HSR, but with considerable variability across labs regarding HS temperature and duration. …

Herbal Extracts As Neuroprotective Agents In An In-Vitro Model Of Aluminum Neurotoxicity, Nada Ezzelarab

Theses and Dissertations

Background: Aluminum toxicity due to environmental or industrial exposure, medical applications, or from cooking utensils is a serious medical problem. The current study aims to investigate three herbal extracts: pomegranate peel extract, Achillea fragrantissima extract, and papaya fruit extract to combat this neurotoxicity.

Methods: Chemical characterization of the three extracts were evaluated using HPLC MS while their neuroprotective activity was assayed using MTT assay on SHSY5Y cells and nitric oxide levels.

Results: Using HPLC-MS chromatography, we have identified twenty-one compounds in the hydro-alcoholic Achillea fragrantissima, seventeen were determined in the pomegranate peel, eleven were assessed in the Carica papaya …

Reducing Seed Coat Fiber Content And Pod Shatter, And Engineering Medium Chain Fatty Acids-Containing Oil, In The Oilseed Crop Pennycress ( Thlaspi Arvense L. ), Maliheh Esfahanian

Theses and Dissertations

The overall goal of this thesis was to genetically improve agronomic traits of pennycress (Thlaspi arvense L.; Field Pennycress) and demonstrate the production of value-added designer seed oils to domesticate pennycress and enable its establishment as a new winter annual oilseed/meal/cover crop to be grown in temperate regions of the world. In the U.S. Midwest, pennycress can be double cropped on existing farmland during the time between corn harvest and subsequent planting of soybeans the following spring. Pennycress has the potential to produce 2,000 lbs/acre seeds, which at 33% by weight oil content and 20% protein, would yield 85 gallons/acre …

Characterizing Ferroptosis Pathways In In Vitro Motor Neuron Models, Alejandra Martinez

Theses and Dissertations

Ferroptosis is a non-apoptotic regulated form of cell death driven by the toxic accumulation of lipid peroxides and the presence of iron. The mechanism by which ferroptosis operates requires further investigation; here I will discuss the findings regarding the role of ferroptosis in different cellular models as well as the genes that may be involved with either promoting or hindering the ferroptotic pathway. NSC-34 is a hybrid cell line of neuroblastoma and primary spinal cord cells that can be differentiated into a motor neuron-like state allowing the characterization of ferroptosis in two distinct cellular conditions. Additionally, iNIL cells are a …

Comparison Of Semi-Automated And Manual Differential Separation Methods For Mock Sexual Assault Samples, Stephanie Rink

Theses and Dissertations

In the event of a sexual assault, separation of suspect from victim DNA is possible through differential extraction if the evidentiary mixture consists of female epithelial cells and male spermatozoa. The basis of differential extraction is the differing properties of epithelial and sperm cell membranes, specifically the comparative sturdiness of the proteins making up the sperm head containing the male DNA. Effective retrieval and separation of male and female DNA fractions is important in generating high-quality STR profiles that can be utilized in identifying suspects in a sexual assault case. Differential extraction has been conventionally performed using Proteinase K (PK) …

A Mechanism Behind The Mechanotransduction Of Surface Characteristics In Osteoblasts, Otto J. Juhl Iv

Theses and Dissertations

Biomaterials for use in bone regeneration and healing range from metal and metal alloy implants to hydrogel-based solutions. These materials can be optimized to increase bone healing and integration by improving the mechanical and biological properties. Regardless of the material itself, the cell-substrate interaction is key to the success of the biomaterial once implanted. Substrate surface characteristics such as roughness, wettability, and particle density are well-known contributors to a substrate’s overall osteogenic potential, and therefore the substrate's overall success. Unfortunately, it is still unknown how these substrate surface characteristics are transduced into intracellular signals by cells, preventing specific tailoring of …

Impact Of Targeting Glycosylated Ceramides On Tumorigenic Properties, And Characterization Of Sphingolipids In Head And Neck Tumors, Katherine E. Hylton

Theses and Dissertations

Sphingolipids play a crucial role in signaling, membrane structure, and migration, making them important molecules in cancer development, metastasis, and drug resistance. While some sphingolipids have been associated with pro-apoptotic or pro-survival behaviors, the role of many sphingolipids in cancer remains poorly defined. Chapter 1 of this study investigated the impact of three enzymes that compose most of the ceramide to Lc3 ceramide pathway – UGCG, GBA, and B3GNT5 – and how their alteration impacts chemoresistance and basal membrane invasion in vitro. It was found that the CΒE-induced inhibition of GBA, which converts glucosylceramide to ceramide, has no effects on …

The Role Of Autophagy And Senescence In The Responses Of Non-Small Cell Lung Cancer Cells To Chemotherapy And Radiation, Nipa H. Patel

Theses and Dissertations

Cancer-associated deaths account for the second-highest mortality rates in the United States. Primary modalities of treatment often include surgery, radiation, and chemotherapy, and may also incorporate targeted therapy and immunotherapy. However, resistance to these treatments remains high, resulting in disease reoccurrence and poor survival rates. While apoptosis or cell death of tumor cells is the ideal outcome for anti-cancer therapy, this is often not the case, and in fact cancer cells may upregulate several pathways, such as autophagy and senescence, as a means to undergo alternative cell fate and evade apoptotic cell death. An essential tumor suppressor gene, TP53, …

A Molecular Toolset For The In Vivo Detection Of A Sulfolobus Islandicus Leucyl Trna Synthetase Paralog, Nicholas Michael Bretz

Theses and Dissertations

An ancient and ubiquitous set of enzymes known as the aminoacyl-tRNA synthetases are required for the viability of all organisms. The aminoacyl-tRNA synthetases catalyze the attachment of amino acids onto tRNA molecules. The aminoacylated, or charged, tRNA is then transported and utilized at the ribosome for the synthesis of proteins. The genome of the hyperthermophilic microorganism Sulfolobus islandicus (S. islandicus) harbors a unique leucyl-tRNA synthetase paralog, LeuRS-I, of unknown function. While its duplicate, LeuRS-F, carries out all the classical functions of LeuRS-family enzymes, LeuRS-I fails to charge leucine onto tRNALeu, despite its ability to activate this amino acid and bind …

Fibrinogen-Conjugated Gold-Coated Magnetite Nanoparticles For Targeting Activated Platelets In A Whole Blood System, Cammy Nu Truong

Theses and Dissertations

Activated platelets are a key component of the arterial thrombi responsible for heart attack and stroke. Tissue plasminogen activator (tPA) is currently the only FDA-approved drug for ischemic stroke. It works by dissolving fibrin, thus breaking down the clot and restoring blood flow to the brain. However, it must be administered within 4.5 hours of the onset of stroke. This leaves a significant number of patients who are ineligible for intervention and who have poor clinical outcomes. Additionally, tPA is not injury site-specific; consequently, the side effects range from mild to severe. We are investigating targeting activated platelets in occlusive …

Effect Of Non-Muscle Myosin Ii Inhibition On Epigenetics During Oligodendrocyte Development, Amr Almaktari

Theses and Dissertations

Non-Muscle Myosin II (NMII) is a mechanosensitive motor protein implicated in oligodendrocyte (OL) development. The inhibition of NMII is known to promote OL development and maturation. This project found that NMII inhibition does not affect oligodendrocyte development by altering their epigenetic profile.

Expression Analyses Of Hippocampal And Cortical Proteins In A Rat Model For Alzheimer’S Disease, Rangon Islam

Theses and Dissertations

Currently, Alzheimer’s disease (AD) has no cure. Using a rat AD model, we identified aberrantly expressed proteins during pre-pathology as potential biomarkers. The expression of certain biomarkers was reversed by diazoxide, a repurposed hypertension drug. These results suggest that drug repurposing at an early stage of AD has therapeutic potential.

Gene Regulatory Mechanisms Driving Temporal Dynamics Of Lineage Specific Differentiation In The Cranial Neural Crest, Maria R. Replogle

Theses and Dissertations

Genetic and environmental perturbations impacting neural crest (NC) development can result in pleiotropic structural and functional birth defects, many of which are associated with pediatric syndromes. As developmental precursors, the NC has the unique capacity to give rise to a diverse array of ectodermal and mesoectodermal cell types, from neurons and glia of the peripheral nervous system to the cartilage and bone of the face. In order to transition from a multipotent progenitor to a specific cell type, NC cells must undergo a series of dynamic morphological and behavioral transformations that gradually unfold over time. However, the NC is rare …

The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine

Theses and Dissertations

Patients with severe lung pathologies, such as Acute Respiratory Distress Syndrome (ARDS), often require mechanical ventilation as a clinical intervention; however, this procedure frequently exacerbates the original pulmonary issue and produces an exaggerated inflammatory response that potentially leads to sepsis, multisystem organ failure, and mortality. This acute lung injury (ALI) condition has been termed Ventilator-Induced Lung Injury (VILI). Alveolar overdistension, cyclic atelectasis, and biotrauma are the primary injury mechanisms in VILI that lead to the loss of alveolar barrier integrity and pulmonary inflammation. Stress and strains during mechanical ventilation are believed to initiate alveolar epithelial mechanotransduction signaling mechanisms that contribute …

Higher Tensile Forces Across Cellular Junctions And An Intact Nuclear Linc Complex Is Required For Epithelial Function And Stability, Fnu Vani Narayanan

Theses and Dissertations

Recent advances in three-dimensional (3D) cell culture systems have provided key insights into the understanding of biochemical and physiological states of native tissue. A significant progress in the field of mechanobiology involves measuring cellular traction forces in a more native 3D environment. However, the effects of mechanical forces exerted across cellular junctions and the nuclear LINC complex, in an organized 3D system has not been investigated thus far. Epithelial cells spontaneously form acini (also known as cysts or spheroids) with a single, fluid-filled central lumen, when grown in 3D matrices. The size of the lumen is dependent on apical secretion …

Disruption Of The Dream Complex Results In Cell Cycle Deregulation, Hayley C. Walston

Theses and Dissertations

The Dimerization Partner, Rb-like, E2F, And MuvB (DREAM) complex was identified in humans due to homology of the genes involved in the D. melanogaster dREAM complex. It assembles during cellular arrest, or G0, to function as a transcriptional repressor of cell cycle genes. It is known that phosphorylation of LIN52 at serine 28 is necessary for the critical DREAM forming interaction between LIN52 and the pocket protein p130. Our laboratory has previously shown that gene editing of LIN52 to replace serine 28 with alanine (S28A) prevents phosphorylation by the kinase DYRK1A and inhibits DREAM formation. Here we have confirmed this …

Regulation Of The Microtubule Cytoskeleton And Cell Wall Development In Arabidopsis Thaliana, Christy J. Fornero

Theses and Dissertations

Regulation of the cortical microtubule cytoskeleton is critical for organized plant cell division. Arabidopsis ton1 and ton2 mutants display random cell division plane placement and lack the plant-specific cortical microtubule array that encircles the nucleus prior to mitosis. In wild type plants, this preprophase band (PPB) of cortical microtubules precisely marks the future division plane. The specific roles of TON1 and TON2 in PPB formation are not yet known. It is suspected that TON1 Recruiting Motif (TRM) proteins may be involved in TON1 and TON2 recruitment to the PPB. Here we describe results for the targeted disruption of a group …

Lorelei Localization And Ovule Ultrastructure In Arabidopsis Thaliana, Juleen May Dickson

Theses and Dissertations

Communication between the male and female gametophyte is vital to successful fertilization during sexual reproduction in plants. One of the proteins known to be important for communication between the male and female gametophyte is LORELEI (LRE). Several studies have shown that there are defects in pollen tube guidance and synergid degeneration, however this is the first study that shows that cell wall thickness in the female gametophyte may also be affected. Previous confocal studies have documented that LRE is present both in the filiform apparatus and found in puncta throughout the cytoplasm. This study confirmed this, but our studies suggest …

An Assessment Of Bsa Protein Hydrogel Biocompatibility In The Vertebrate Intestinal Tract, Ryan Joseph Garde

Theses and Dissertations

The fields of biomedicine and pharmacology have a mission to design methods to treat disease while minimizing adverse side effects using novel drug delivery systems. In developing new therapeutic systems, it is crucial to test that drug delivery systems target pathological cells and tissue and is non-toxic in healthy tissue. One promising method for targeted drug delivery is the use of hydrogels as carriers. Here, we studied the effects of bovine serum albumin (BSA) hydrogel consumption to assess the potential for hydrogel use in treating intestinal disease via oral administration. We investigated intestinal architecture and cell populations following hydrogel treatments …

Characterization Of Pth Type-2 Receptor ( Pth2rb ) And Its Endogenous Ligand Pth2 In Zebrafish Development, Nicholas Seitz

Theses and Dissertations

Members of the parathyroid hormone family of ligands, PTH (parathyroid hormone), PTH2, and PTHLH (parathyroid hormone-like hormone). These hormones interact with the class B GCPRs parathyroid hormone receptors PTH1R, PTH2R, and PTH3R to regulate a variety of biological processes. In mammals, PTH and PTHLH activate PTH1R and PTH3R to mediate serum calcium homeostasis, chondrogenesis, and bone maintenance. PTH2R activation by PTH2 has been studied primarily in regard to its neuroendocrine roles but is also found in the skin where it contributes to wound healing and keratinocyte differentiation. Still, little is known about the impacts of PTH2R signaling relative to PTH1R …

Molecular Mechanisms Mediating Morphogenesis Of The Basal Epithelial Tissue Fold During Midbrain-Hindbrain Boundary Formation In Zebrafish, Mike Roger Visetsouk

Theses and Dissertations

ABSTRACT

MOLECULAR MECHANISMS MEDIATING MORPHOGENESIS OF THE BASAL EPITHELIAL TISSUE FOLD DURING MIDBRAIN-HINDBRAIN BOUNDARY FORMATION IN ZEBRAFISH

by

Mike Roger Visetsouk

The University of Wisconsin-Milwaukee, 2019

Under the Supervision of Jennifer H. Gutzman, PhD

The formation of a fully functional organism requires the morphogenesis of cell and tissue structures during development. It is important to understand the mechanisms that mediate morphogenesis, since cell and tissue structures are crucial to physiological function. Here, we studied basal epithelial tissue folding as a model to determine the mechanisms of morphogenesis. We investigated a highly conserved basal tissue fold known as the midbrain-hindbrain boundary …