Life Sciences Commons^™

Serine-Dependent Sphingolipid Synthesis Is A Metabolic Liability Of Aneuploid Cells, Sunyoung Hwang, H. Tobias Gustafsson, Ciara O’Sullivan, Gianna Bisceglia, Xinhe Huang, Christian Klose, Andrej Schevchenko, Robert C. Dickson, Paola Cavaliere, Noah Dephoure, Eduardo M. Torres

Molecular and Cellular Biochemistry Faculty Publications

Aneuploidy disrupts cellular homeostasis. However, the molecular mechanisms underlying the physiological responses and adaptation to aneuploidy are not well understood. Deciphering these mechanisms is important because aneuploidy is associated with diseases, including intellectual disability and cancer. Although tumors and mammalian aneuploid cells, including several cancer cell lines, show altered levels of sphingolipids, the role of sphingolipids in aneuploidy remains unknown. Here, we show that ceramides and long-chain bases, sphingolipid molecules that slow proliferation and promote survival, are increased by aneuploidy. Sphingolipid levels are tightly linked to serine synthesis, and inhibiting either serine or sphingolipid synthesis can specifically impair the fitness …

Regulation Of Liver Mitochondrial Metabolism During Hibernation By Post-Translational Modification, Katherine E. Mathers

Electronic Thesis and Dissertation Repository

Hibernation, characterized by a seasonal reduction in metabolism and body temperature, allows animals to conserve energy when environmental conditions (e.g. temperature, food availability) are unfavourable. During hibernation, small mammals such as the 13-lined ground squirrel (Ictidomys tridecemlineatus) cycle between two distinct metabolic states: torpor, where metabolic rate is suppressed by >95% and body temperature falls to ~5 °C, and interbout euthermia (IBE), where metabolic rate and body temperature rapidly increase and are maintained at euthermic levels several hours. Suppression of metabolism during entrance into torpor is paralleled by rapid suppression of liver mitochondrial metabolism. In my thesis, I …

Cholesterol Regulation Of Pulmonary Endothelial Calcium Entry Following Chronic Hypoxia, Bojun Zhang

Biomedical Sciences ETDs

Chronic hypoxia (CH)-induced pulmonary hypertension (PH) is associated with diminished ATP-induced endothelial Ca2+ entry as well as membrane cholesterol in pulmonary arteries. Store-operated Ca2+ entry (SOCE) and depolarization-induced Ca2+ entry are major components of the response to ATP and are similarly decreased after CH. Because endothelium-dependent vasodilation is closely associated with pulmonary endothelial [Ca2+]i, the blunted agonist-induced Ca2+ influx in pulmonary artery endothelial cells (PAEC) may contribute to the development of CH-induced PH. Interestingly, impaired agonist-induced Ca2+ influx in PAEC following CH can be restored by membrane cholesterol supplementation. In the current studies, we hypothesized that impaired Ca2+ entry in …

Insights Into The Therapeutic Potential Of Salt Inducible Kinase 1: A Novel Mechanism Of Metabolic Control, Randi Fitzgibbon

Dissertations & Theses (Open Access)

Salt inducible kinase 1 (SIK1) has been considered a stress-inducible kinase since it was first cloned in 1999. Continued efforts since this time have been dedicated to characterizing the structure and function of SIK1. Such research has laid the ground work for our understanding of SIK1 action and regulation in tissue and stimuli dependent manners. The fundamental findings of this dissertation continue in this tradition and include investigations of SIK1 regulatory mechanisms in skeletal muscle cells, the cellular and physiological effects of SIK1 loss of function in vitro and in vivo, and intracellular metabolic and mitochondrial regulation by this …

Exogenous Ubiquitin: Role In Myocardial Inflammation And Remodeling Post- Ischemia/Reperfusion Injury, Stephanie Scofield

Electronic Theses and Dissertations

Sympathetic stimulation occurs in the heart after injuries such as ischemia/reperfusion (I/R) and myocardial infarction and affects myocardial remodeling. Prolonged sympathetic stimulation can result in myocardial dysfunction through its effects on cardiac myocyte apoptosis and myocardial fibrosis. Ubiquitin (UB) is well known for its role of tagging old or damaged proteins for degradation via the UB-proteosome pathway. The role of exogenous UB however, is not fully understood. Previously, our lab showed that β-adrenergic receptor (β-AR) stimulation increased levels of extracellular UB in the conditioned media of adult rat ventricular myocytes and that UB inhibits β-AR-stimulated apoptosis. This study investigates the …

Examining The Electrical Excitation, Calcium Signaling, And Mechanical Contraction Cycle In A Heart Cell, Kristen Deetz, Nygel Foster, Darius Leftwich, Chad Meyer, Shalin Patel, Carlos Barajas, Matthias K. Gobbert, Zana Coulibaly

Spora: A Journal of Biomathematics

As the leading cause of death in the United States, heart disease has become a principal concern in modern society. Cardiac arrhythmias can be caused by a dysregulation of calcium dynamics in cardiomyocytes. Calcium dysregulation, however, is not yet fully understood and is not easily predicted; this provides motivation for the subsequent research. Excitation-contraction coupling (ECC) is the process through which cardiomyocytes undergo contraction from an action potential. Calcium induced calcium release (CICR) is the mechanism through which electrical excitation is coupled with mechanical contraction through calcium signaling. The study of the interplay between electrical excitation, calcium signaling, and mechanical …

Neuronal Degeneration And Short-Term Memory Impairment After Tbi, Obiamaraije Igwe

Posters-at-the-Capitol

Traumatic brain injury (TBI) was associated with impaired short-term memory with causes of vehicle accidents and falls. Protein plaques containing fibrinogen (Fg), are associated with memory loss. After TBI, Fg in blood was higher than normal (>~2 mg/ml), which resulted in increased Fg in extravascular space. Therefore, Fg bonded to its endothelial receptor intercellular adhesion molecule-1 (ICAM-1). Fg then interacted with cellular prion protein (PrPC), which had a strong effect on the loss of memory and cognition. Mechanisms of Fg and PrPC complex formation and its functional implication are not known. This present study tested the level of Fg-PrPC …

No Difference In Myosin Kinetics And Spatial Distribution Of The Lever Arm In The Left And Right Ventricles Of Human Hearts, Divya Duggal, S. Requena, Janhavi Nagwekar, Sangram Raut, Ryan Rich, Hriday Das, Vipul Patel, Ignacy Gryczynski, Rafal Fudala, Zygmunt Gryczynski, Cheavar Blair, Kenneth S. Campbell, Julian Borejdo

Physiology Faculty Publications

The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. …

Heads And Tails, Julie Simons

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Direct Antioxidant Properties Of Methotrexate: Inhibition Of Malondialdehyde-Acetaldehyde-Protein Adduct Formation And Superoxide Scavenging., Matthew C. Zimmerman, Dahn L. Clemens, Michael J. Duryee, Cleofes Sarmiento, Andrew Chiou, Carlos D. Hunter, Jun Tian, Lynell W. Klassen, James R. O'Dell, Geoffrey M. Thiele, Ted R. Mikuls, Daniel R. Anderson

Journal Articles: Cellular & Integrative Physiology

Methotrexate (MTX) is an immunosuppressant commonly used for the treatment of autoimmune diseases. Recent observations have shown that patients treated with MTX also exhibit a reduced risk for the development of cardiovascular disease (CVD). Although MTX reduces systemic inflammation and tissue damage, the mechanisms by which MTX exerts these beneficial effects are not entirely known. We have previously demonstrated that protein adducts formed by the interaction of malondialdehyde (MDA) and acetaldehyde (AA), known as MAA-protein adducts, are present in diseased tissues of individuals with rheumatoid arthritis (RA) or CVD. In previously reported studies, MAA-adducts were shown to be highly immunogenic, …

Prevention Of Renal Apob Retention Is Protective Against Diabetic Nephropathy: Role Of Tgf-Β Inhibition, Patricia G. Wilson, Joel C. Thompson, Meghan S. Yoder, Richard Charnigo, Lisa R. Tannock

Internal Medicine Faculty Publications

Animal studies demonstrate that hyperlipidemia and renal lipid accumulation contribute to the pathogenesis of diabetic nephropathy (DN). We previously demonstrated that renal lipoproteins colocalize with biglycan, a renal proteoglycan. The purpose of this study was to determine whether prevention of renal lipid (apoB) accumulation attenuates DN. Biglycan-deficient and biglycan wild-type Ldlr^−/− mice were made diabetic via streptozotocin and fed a high cholesterol diet. As biglycan deficiency is associated with elevated transforming growth factor-β (TGF-β), in some experiments mice were injected with either the TGF-β-neutralizing antibody, 1D11, or with 13C4, an irrelevant control antibody. Biglycan deficiency had no significant effect …

The Role Of T-Box Proteins In Vertebrate Germ Layer Formation And Patterning, Sushma Teegala

Dissertations, Theses, and Capstone Projects

All of the tissues in triploblastic organisms, with the exception of the germ cells, arise from the three germ layers, ectoderm, mesoderm and the endoderm. The identification of the genes that underlie the differentiation of these layers is crucial to our understanding of development. T-box family proteins are DNA-binding transcriptional regulators that play important roles during germ layer formation in the early vertebrate embryo. Well-characterized members of this family, including the transcriptional activators Brachyury and VegT, are essential for the proper formation of mesoderm and endoderm, respectively. To date, T-box proteins have not been shown to play a role in …

Proteomic Analysis Of The Crustacean Molting Gland (Y-Organ) Over The Course Of The Molt Cycle, Talia B. Head

Master's Theses

Molting in crustaceans is a highly complex physiological process involving negative regulation by two paired endocrine glands, the X-organ/sinus gland complex (XO/SG) and the Y-organ (YO). The XO/SG complex is responsible for making molt-inhibiting hormone (MIH) which negatively regulates synthesis of the molting hormones, ecdysteroids, by the YO. Analysis of gene expression in the XOs and YOs has led to the development of a proposed molecular signaling pathway which regulates ecdysteroidogenesis and subsequent molting in crustaceans. In this study, changes in protein abundance in the YO were characterized over the course of a molt cycle (intermolt, early premolt, mid premolt, …

Translational Fidelity, Mistranslation, And The Cellular Responses To Stress, Kyle Mohler, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Faithful translation of mRNA into the corresponding polypeptide is a complex multistep process, requiring accurate amino acid selection, transfer RNA (tRNA) charging and mRNA decoding on the ribosome. Key players in this process are aminoacyl-tRNA synthetases (aaRSs), which not only catalyse the attachment of cognate amino acids to their respective tRNAs, but also selectively hydrolyse incorrectly activated non-cognate amino acids and/or misaminoacylated tRNAs. This aaRS proofreading provides quality control checkpoints that exclude non-cognate amino acids during translation, and in so doing helps to prevent the formation of an aberrant proteome. However, despite the intrinsic need for high accuracy during translation, …

Inhibition Of Post-Transcriptional Steps In Ribosome Biogenesis Confers Cytoprotection Against Chemotherapeutic Agents In A P53-Dependent Manner, Russell T Sapio, Anastasiya N Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J Manna, Natalie Minkovsky, Dimitri G Pestov

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The p53-mediated nucleolar stress response associated with inhibition of ribosomal RNA transcription was previously shown to potentiate killing of tumor cells. Here, we asked whether targeting of ribosome biogenesis can be used as the basis for selective p53-dependent cytoprotection of nonmalignant cells. Temporary functional inactivation of the 60S ribosome assembly factor Bop1 in a 3T3 cell model markedly increased cell recovery after exposure to camptothecin or methotrexate. This was due, at least in part, to reversible pausing of the cell cycle preventing S phase associated DNA damage. Similar cytoprotective effects were observed after transient shRNA-mediated silencing of Rps19, but not …

Carotid Body-Mediated Chemoreflex Drive In The Setting Of Low And High Output Heart Failure., Rodrigo Del Rio, David C. Andrade, Camilo Toledo, Hugo S. Diaz, Claudia Lucero, Alexis Arce-Alvarez, Noah J. Marcus, Harold D. Schultz

Journal Articles: Cellular & Integrative Physiology

Enhanced carotid body (CB) chemoreflex function is strongly related to cardiorespiratory disorders and disease progression in heart failure (HF). The mechanisms underlying CB sensitization during HF are not fully understood, however previous work indicates blood flow per se can affect CB function. Then, we hypothesized that the CB-mediated chemoreflex drive will be enhanced only in low output HF but not in high output HF. Myocardial infarcted rats and aorto-caval fistulated rats were used as a low output HF model (MI-CHF) and as a high output HF model (AV-CHF), respectively. Blood flow supply to the CB region was decreased only in …

Distinct Roles Of Gaba(A)R Signaling In The Regulation Of Two Human T Lymphocyte Lines, Ying Lin

Electronic Thesis and Dissertation Repository

In response to antigen presentation, helper T lymphocytes (T_H cells) initiate store-operated Ca²⁺ entry (SOCE) and differentiate into effector subtypes such as T_H1 and T_H2 cells. These cells play essential roles in adaptive immunity and the pathogenesis of various autoimmune and allergic diseases. The differentiation and activity of T_H cells are also critically regulated by paracrine and autocrine soluble factors in the cell microenvironment. Previous studies have reported that T_H cells produce gamma-aminobutyric acid (GABA) via glutamic acid decarboxylase (GAD) and express A-type GABA receptors (GABA_ARs), forming an autocrine GABA …

Carbonyl Reduction By Ymfi Completes The Modification Of Ef-P In Bacillus Subtilis To Prevent Accumulation Of An Inhibitory Modification State, Katherine R. Hummels, Anne Witzky, Andrei Rajkovic, Rodney Tollerson Ii, Lisa A. Jones, Michael Ibba, Daniel B. Kearns

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translation elongation factor P (EF‐P) in Bacillus subtilis is required for a form of surface migration called swarming motility. Furthermore, B. subtilis EF‐P is post‐translationally modified with a 5‐aminopentanol group but the pathway necessary for the synthesis and ligation of the modification is unknown. Here we determine that the protein YmfI catalyzes the reduction of EF‐P‐5 aminopentanone to EF‐P‐5 aminopentanol. In the absence of YmfI, accumulation of 5‐aminopentanonated EF‐P is inhibitory to swarming motility. Suppressor mutations that enhanced swarming in the absence of YmfI were found at two positions on EF‐P, including one that changed the conserved modification site (Lys …

Chaperoning Ef Hands That Shape Calcium Response: Ncald, Hpca And S100b, Jingyi Zhang

Graduate School of Biomedical Sciences Theses and Dissertations

All organisms have an internal clock with a defined period between repetitions of activities. The period for circadian clock in human is 24.5 hours, while in mouse and rat, it is 23.5 hours. However, all organisms are forced to be in synchronization with their environment. A major environmental force that resets the internal clock to 24 hours is light. This phenomenon is defined as “light entrainment” or “phase-setting”. It is unclear how this entrainment process occurs. Studies from this laboratory indicate a role for two neuronal calcium sensor proteins: Neurocalcin  (NCALD) and S100B. For these two genes, mRNA as …

Molecular Mechanisms Of Dna Replication Initiation In Hpvs With Genetic Variations Leading To Cellular Carcinogenesis, Gulden Yilmaz

Graduate School of Biomedical Sciences Theses and Dissertations

Human papillomaviruses are a vast family of double-stranded DNA viruses containing non-carcinogenic and carcinogenic types, whose crucial differences remain unknown, except for the difference in the frequency of DNA replication. The human papillomavirus (HPV) E2 protein regulates the initiation of viral DNA replication and transcription. Its recognition and binding to four 12 bp palindromic sequences in the viral origin is essential for its function. Little is known about the DNA binding mechanism of the E2 protein found in HPV types that have low risk for oncogenicity (low-risk) as well as the roles of various elements of the individual binding sites. …

Preclinical Development Of Therapeutic Strategies Against Triple-Negative And Inflammatory Breast Cancer, Angie M. Torres-Adorno

Dissertations & Theses (Open Access)

Triple-negative (TNBC) and inflammatory (IBC) breast cancer are the most aggressive forms of breast cancer, accounting for 20% and 10% of cancer-related deaths, respectively. Among IBC cases, 30% are additionally classified with TNBC molecular pathology, a diagnosis that significantly worsens patient’s prognosis. The current lack of TNBC and IBC molecular understanding prevents the development of effective therapeutic strategies. To identify effective treatments, we explored aberrant apoptosis pathways and cell membrane fluidity as novel therapeutic targets.

We first identified an effective therapeutic strategy against TNBC and IBC by pro-apoptotic protein NOXA-mediated inhibition of the anti-apoptotic protein MCL1 following inhibition of histone …

Noninvasive Measures Of Stress And Lameness In Broilers, Shawna L. Weimer

Graduate Theses and Dissertations

The concept of broiler chicken welfare has evolved from a component of animal husbandry to a label on a chicken product package. Recent attention from the public has led to the need for higher welfare standards for animal production. A primary concern of broiler production is low activity/locomotion attributed to fast growth rates leading to poor leg health. To collect the scientific data necessary to determine conditions providing the best welfare for the bird, multiple methods of assessment are required. Stress is influenced by external (temperature, humidity, lighting, stocking density) and internal (metabolism, thermoregulation, hormonal balance) factors. This series of …

Mitochondrial Transcription Factor A'S Role In Heart Failure., George H. Kunkel

Electronic Theses and Dissertations

Background: An essential mitochondrial component, Mitochondrial Transcription Factor A (TFAM) is reduced within the failing heart. TFAM maintains regulatory functions of cardiomyocyte physiology and stability. Mitochondrial Transcription Factor A forms a mitochondrial nucleoid anti-oxidant structure and reduces pathophysiological abnormalities to structural and contractile proteins. Overall, this functions to physically stabilize mtDNA. Significant molecular changes such as a loss of TFAM drive pathophysiological concentrations of cytoplasmic Ca2+ and reactive oxygen species. Both of these factors induce proteolytic enzymes to degrade the physiological cardiomyocyte. In TFAMs absence, heart function deteriorates and hypertrophic expansion ensues: thereby changing the physiological myocardium to a pathological …

Elongation Factor P Interactions With The Ribosome Are Independent Of Pausing, Rodney Tollerson Ii, Anne Witzky, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacterial elongation factor P (EF-P) plays a pivotal role in the translation of polyproline motifs. To stimulate peptide bond formation, EF-P must enter the ribosome via an empty E-site. Using fluorescence-based single-molecule tracking, Mohapatra et al. (S. Mohapatra, H. Choi, X. Ge, S. Sanyal, and J. C. Weisshaar, mBio 8:e00300-17, 2017, https://doi.org/10.1128/mBio.00300-17 ) monitored the cellular distribution of EF-P and quantified the frequency of association between EF-P and the ribosome under various conditions. Findings from the study showed that EF-P has a localization pattern that is strikingly similar to that of ribosomes. Intriguingly, EF-P was seen to bind ribosomes more …

Functional Characteristics Of Four Novel Lone Atrial Fibrillation-Linked Connexin40 Mutants, Mahmoud Noureldin

Electronic Thesis and Dissertation Repository

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. Recently, four novel heterozygous Cx40 mutations, K107R, L223M, Q236H, and I257L were identified in 4 of 310 unrelated AF patients. To study possible alterations associated with these mutants, we studied their localization and function using gap junction (GJ)-deficient model cells. Cell pairs expressing Q236H alone or together with wildtype Cx43 showed a significantly lower coupling conductance. Impaired GJ function and dominant negative action on Cx43 of this mutant are consistent with previous findings on the majority of AF-linked Cx40 mutants. The remaining three novel AF-linked mutants did not show …

Hepatic Changes Associated With Chronic Alcohol Exposure In An Alpha-1 Antitrypsin Piz Mouse Model, Zhuoyao Lyu, Alisha M. Gruntman, Brian O'Sullivan-Murphy, Christian Mueller, Terence R. Flotte

Christian Mueller

The PiZ mutation in the alpha-1 antitrypsin (AAT) gene causes the PiZ mutant protein to be sequestered in the endoplasmic reticulum of hepatocytes, causing significant liver pathology in ~10% of PiZZ homozygous AAT disease patients. Current transgenic mouse models of the disease include the liver-specific over-expression of mutant PiZ protein. However, these animal models do not efficiently recapitulate the liver damage found in PiZZ homozygous patients. Since only a small percentage of patients develop liver disease and it is not reproducible in animal models of AATD, it suggests that there are other factors that participate in disease pathogenesis. Here, we …

Girk2 And Gababr1 Downregulate In Response To Ttx As Girk2, Gababr1, And Gababr2 Are Not Affected By Bc Treatment, Staci E. Hammer, Amanda Weiss, Hee Jung Chung

PRECS student projects

Homeostatic plasticity is the response neurons undergo to regulate changes in excitability levels and bring the cells back to homeostasis. Research on homeostatic plasticity at the molecular level can lead to improved treatments for neurological diseases such as epilepsy, Alzheimer's, and schizophrenia. The research featured in this poster looks at the response of GIRK (G protein-gated inwardly rectifying potassium) channels and GABAb (gamma-amniobutyric acid) receptors to neurotoxins, tetrodotoxin (TTX) or bicuculline (BC).

Prolonged activity blockade of 48 hour TTX treatment significantly reduced GABABR1 and GIRK2 expression. This supports the idea that because these two proteins inhibit action potentials, there will …

The Role Of P62/Sqstm1 In Tgfβ-Dependent Emt And Autophagy, Evelyn Ng

Electronic Thesis and Dissertation Repository

Transforming growth factor beta (TGFβ) is a cytokine that regulates cellular adhesion, proliferation and apoptosis. In the context of cancer, TGFβ induces processes such as epithelial-to-mesenchymal transition (EMT). More recently, TGFβ has been discovered to also induce autophagy, and the relationship between TGFβ-induced EMT and autophagy remains unknown. Due to its involvement in autophagy and its established interactions with key TGFβ signaling proteins, this thesis focuses on the sequestosome 1 (p62/SQSTM1) protein. Here, I have shown that p62/SQSTM1 co-localizes with TGFβ receptors at the same time point that the receptors localize to Rab7-positive late endosomes. siRNA-mediated silencing of p62/SQSTM1 was …

H2s And Homocysteine Control A Novel Feedback Regulation Of Cystathionine Beta Synthase And Cystathionine Gamma Lyase In Cardiomyocytes., Shyam Sundar Nandi, Paras K. Mishra

Journal Articles: Cellular & Integrative Physiology

Hydrogen sulfide (H2S), a cardioprotective gas, is endogenously produced from homocysteine by cystathionine beta synthase (CBS) and cystathionine gamma lyase (CSE) enzymes. However, effect of H2S or homocysteine on CBS and CSE expression, and cross-talk between CBS and CSE are unclear. We hypothesize that homocysteine and H2S regulate CBS and CSE expressions in a dose dependent manner in cardiomyocytes, and CBS deficiency induces cardiac CSE expression. To test the hypothesis, we treated murine atrial HL1 cardiomyocytes with increasing doses of homocysteine or Na2S/GYY4137, a H2S donor, and measured the levels of CBS and CSE. We found that homocysteine upregulates CSE …

The Effects Of Fluoride Ions On Neuromuscular Activity And Regeneration In Dugesia Tigrina, John Williams Jr.

Georgia Journal of Science

Fluoride ions have been implicated in numerous nervous system pathologies, though the association of these ions with these conditions has been controversial. The purpose of this research is to determine the effects that fluoride ions have on the nervous system development and function in planarians as a simple model for fluoride-nervous system interactions. In the first set of experiments, planarians were exposed to one of four concentrations of sodium fluoride: 0 mM, 1 mM, 1 mM, and 5 mM. In the second set of experiments, planarians were bisected and exposed to 1 mM of NaCl and NaF for regeneration purposes. …