Medicine and Health Sciences Commons^™

Cardiac Arrest And Global Ischemia Reperfusion Injury: Role Of Mitochondria And Cannabinoid Receptor 2 Signaling., Jennifer L. Bradley

Theses and Dissertations

We explored the effects of cardiac arrest on mitochondria populations and heart whole tissue lysate proteomics utilizing the Weil Institute’s in vivo rat model of cardiac arrest and cardiopulmonary resuscitation. We have discovered that brain mitochondria are more sensitive to global ischemia compared to heart mitochondria. Additionally, complex I is the most sensitive electron transport chain complex to ischemic injury and is a major control point of the rate of oxidative phosphorylation following cardiac arrest and cardiopulmonary resuscitation. Preservation of brain mitochondrial activity and function during cardiac arrest may enhance outcomes and recovery.

A recent article focusing on acute myocardial …

A High Fructose Diet Alters Affective-Like Behavior And Metrics Of Synaptic Mitochondrial Function Differentially In Male And Female Rats, Alix H. Kloster

Theses and Dissertations

Fructose consumption has become a normalized part of the standard American diet over the past 40 years. While fructose consumption is a known risk factor of metabolic syndrome, there is increasing evidence that fructose consumption influences brain and behavior. Recently, more interest has been focused on mitochondrial dysfunction as a potential link between metabolic stress and modifications of the central nervous system. Mitochondria are in the unique position of both regulating and being vulnerable to alterations in energy homeostasis. Sex-differences are well categorized in the presentation of metabolic symptoms associated with excessive fructose consumption. Thus, it is important to characterize …

Modulation Of Electron Transport By Metformin In Cardiac Protection: Role Of Complex I, Ahmed Abdul Hussein Mohsin

Theses and Dissertations

Modulation of mitochondrial complex I during reperfusion reduces cardiac injury. Complex I exists in two structural states: active (A) and deactive (D) with transition from A→D during ischemia. Reperfusion reactivates D→A with an increase in ROS production. Metformin preserves the D-Form. Our aim was to study the contribution of maintenance of deactivation of complex I during early reperfusion by metformin to protect against ischemia reperfusion injury. Our results showed that metformin decreased H9c2 cardiomyoblast apoptosis and total cell death following simulated ischemia for six hours followed by reoxygenation for twenty four hours compared to untreated cells. Reactive oxygen species (ROS) …

Determining The Effect Of Knocking Out Microrna-21 On Subsarcolemmal And Interfibrillar Mitochondria, Madhur Batra

Theses and Dissertations

Type 2 diabetes mellitus is a growing problem across the world and has significant pathological changes associated with it, including diabetic cardiomyopathy, wherein cardiac function is reduced. MicroRNA-21 has been shown to play a role in both the heart and diabetes so it was thought that knocking out miR-21 could have a protective effect on oxidative phosphorylation function in diabetic mice. Subsarcolemmal and interfibrillar mitochondria were isolated from adult male WT, miR-21 KO, db/db, and double knockout mice (db/db and miR-21 KO cross) and evaluated for function. Knocking out miR-21 in diabetic mice showed a restorative effect in Complex I …

A Mechanistic Study Of An Ipsc Model For Leigh’S Disease Caused By Mtdna Mutataion (8993 T>G), John P. Galdun

Theses and Dissertations

Mitochondrial diseases encompass a broad range of devastating disorders that typically affect tissues with high-energy requirements. These disorders have been difficult to diagnose and research because of the complexity of mitochondrial genetics, and the large variability seen among patient populations. We have devised and carried out a mechanistic study to generate a cell based model for Leigh’s disease caused by mitochondrial DNA mutation 8993 T>G. Leigh’s disease is a multi-organ system disorder that depends heavily on the mutation burden seen within various tissues. Using new reprogramming and sequencing technologies, we were able to show that Leigh’s disease patient fibroblasts …

Mitochondrial Biogenesis And Electrical Properties Of Hpsc-Derived Motor Neurons, Laura O'Brien

Theses and Dissertations

Human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) hold great promise in the fields of drug development and regenerative medicine. If iPSCs reprogrammed from patient cells replicate what is seen in vivo they may be used as a model of disease. A process that is disrupted in many neurodegenerative diseases is mitochondrial biogenesis. One of these diseases is amyotrophic lateral sclerosis (ALS), which is characterized by loss of motor neurons in the brain and spinal cord. Differentiation of hPSCs into motor neurons offers a way to study a previous unavailable cell …

Relationship Of Mitochondrial Enzymes To Fatigue Intensity And Health-Related Quality Of Life In Men With Prostate Cancer Receiving External Beam Radiation Therapy, Kristin Filler

Theses and Dissertations

Introduction: Cancer-related fatigue is often described by patients as a lack of energy, mental or physical tiredness, diminished endurance, and prolonged recovery after activity. Etiologic mechanisms underlying CRF are not well understood. Methods: A literature review was conducted to examine studies that had investigated the association of mitochondrial dysfunction with fatigue. The major conclusion from this review was that alterations in energy metabolism may contribute to fatigue. Therefore, the dissertation study focused on laboratory techniques for measuring mitochondrial oxidative phosphorylation enzymes (complexes I-V) and a mitochondrial-specific oxidative stress marker (superoxide dismutase 2 [SOD2]). The primary aim of the dissertation research …

The Effect Of Isocitrate Dehydrogenase On The Epigenetics Of Human Mitochondrial Dna, John Strang

Theses and Dissertations

Aberrant metabolism has become an increasingly interesting area of cancer biology. In many cancers including lower grade glioma, glioblastomas and some leukemias, a mutation in the metabolic enzyme Isocitrate Dehydrogenase (IDH), has been found in more than 70% of cases and has been shown to lead to a distinct hypermethylator phenotype. IDH commonly converts isocitrate to alpha-ketoglutarate in normal cell metabolism. Three isoforms of this enzyme are found in humans: IDH1, IDH2 and IDH3. Studies on IDH1, the cytosolic isoform, have revealed that mutations in the enzyme’s binding site lead to a novel gain of function: the synthesis of an …

Mitochondrial Gene Expression In Human Mononuclear Cells, Monika Ruchala

Theses and Dissertations

MITOCHONDRIAL GENE EXPRESSION IN HUMAN MONONUCLEAR CELLS By Monika D. Ruchała, M.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2014. Director: Dr. James P. Bennett Jr, M.D., Ph.D., Bemiss Professor Departments of Neurology, Psychiatry and Physiology and Biophysics Adult neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), have been intensively studied in recent years in pursuit of mechanisms responsible for origin and progression. One emerging theme is mitochondrial energetic deficiency as a mechanism of neuronal death. Recent descriptions of protocols to generate induced pluripotent stems …

Elucidation Of Mechanisms Generating 5-Hydroxymethylcytosine (5hmc) In Mammalian Mitochondria, Prashant Thakkar

Theses and Dissertations

DNA methylation plays a pivotal role in governing cellular processes including genomic imprinting, gene expression, and development. Recently, the Tet family of methylcytosine dioxygenases(Tet1, Tet2 and Tet3) was found to catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), an intermediate in the pathway of DNA demethylation. Tet enzymes catalyze this hydroxylation in a 2-oxoglutarate and Fe2+ dependent manner. We have recently reported significant levels of 5mC and 5hmC modification in immunoprecipitates of mammalian mitochondrial DNA(mtDNA). We provide the first evidence that a DNA Methyltransferase-1 isoform (mtDNMT1) translocates to the mitochondria using an N-terminal mitochondrial targeting sequence. mtDNMT1 expression is …

Functional Consequences Of Cytosine Methylation In Mitochondrial Dna Catalyzed By Dna Methyltransferase 1, Lisa Shock

Theses and Dissertations

Cytosine methylation of mitochondrial DNA (mtDNA) was first described several decades ago, but neither the mechanism generating this modification nor its functional significance was known. Because mitochondrial dysfunction is a hallmark characteristic of numerous human diseases, including neurological and cardiovascular disease, aging and cancer, this dissertation addressed whether epigenetic modification of mtDNA regulates mitochondrial function. We show that mtDNA contains not only 5-methylcytosine (5mC), but also 5-hydroxymethylcytosine (5hmC), suggesting that previous reports likely underestimated the degree of epigenetic modification within the mitochondrial genome. We questioned how these modifications were generated by looking for mitochondrial isoforms of the nuclear-encoded DNA methyltransferases. …

The Mechanism Of Mitochondrial Folate Transport By The Mitochondrial Folate Transporter, Scott Alan Lawrence

Theses and Dissertations

The mitochondrial folate transport protein (MFT) functions to transport folates into the mitochondrial matrix. The MFT is a member of a mitochondrial carrier family (MCF) of proteins that have a high degree of sequence and structural similarities, yet they transport vastly different substrates at high specificities. In this dissertation research, the folate-specific transport mechanism of the MFT was explored using experimental and computational techniques. MFT residues that differed from MCF consensus residues in conserved PxD/ExxK/R motifs and at a predicted substrate-binding site common to all MCF proteins were investigated. Site-directed mutagenesis of these anomalous residues in the MFT revealed that …

Action Of Tyrosyl Dna Phosphodiesterase On 3'-Phosphoglycolate Terminated Dna Strand Breaks, Haritha Tatavarthi

Theses and Dissertations

Free radical-mediated DNA double strand breaks (DSBs) are induced either directly by ionizing radiation or by certain chemicals like bleomycin. These breaks are terminated by 3'-PG (PO4CH2COOˉ) or 3'-phosphate groups formed as a result of fragmentation of deoxyribose. To study the nature of repair of these 3'-blocked breaks, we constructed substrates mimicking free-radical induced DSBs. Human and yeast tyrosyl DNA-phosphodiesterase (Tdpl) efficiently processed substrates with 3'-PGs, in either the presence or absence of magnesium, to give a 3'-phosphate. Gel filtration chromatography and western blotting codmed that the putative enzyme in human extracts that efficiently processed PG was indeed tyrosyl DNA-phosphodiesterase. …

Interleukin-10 Induces Apoptosis In Developing Mast Cells Via A Mitochondrial, Stat3-Dependent Pathway, Daniel Paul Bailey

Theses and Dissertations

Objective. The aim of this study was to determine the effects of interleukin-10 on mast cell development from bone marrow progenitors.Materials and Methods. Unseparated mouse bone marrow cells were cultured in IL-3+SCF, giving rise to mast cells and monocytes/macrophages. The addition of IL-10, and the use of Signal Transducer and Activator of Transcription (STAT)3-deficient bone marrow cells were employed to measure the effects of IL-10 and STAT3 expression on cell viability, proliferation, and differentiation. Bax-deficient and Bcl-2 transgenic bone marrow cells were used to determine the importance of the mitochondria in IL-10-mediated effects.Overview. Mast cells arise from hematopoietic stem cells …