Life Sciences Commons^™

Sex Differences In Stroke Recovery: Synaptic Proteins And The Growth Inhibitory Protein Nogo A, Vincent Joseph Borkowski

Dissertations

Ischemic stroke is a major world-wide health problem, resulting in death and disability especially in the older population. A sex difference exists in functional recovery post-stroke, with post-menopausal women having worse functional outcome as compared to age-matched men. Although the mechanisms underlying this sex difference are not entirely clear, it is recommended that any potential therapy for stroke recovery be tested in pre-clinical models including both male and females in order to determine the efficacy of the proposed treatment on the entire population. We have reported a novel therapy to enhance brain plasticity and improve functional recovery after stroke in …

Critical Role Of C-Jun N-Terminal Kinase Signaling In Binge Alcohol-Driven Atrial Arrhythmic Remodeling, Jiajie Yan Yan

Dissertations

Holiday Heart Syndrome (HHS) is cardiac arrhythmia induced by binge alcohol consumption, a drinking pattern affects 38 million adults in our society. Atrial fibrillation (AF) is the most frequently diagnosed arrhythmia in HHS and causes significant morbidity and mortality. Despite the intensive prevention effort nationwide, the binge drinking population keeps rising. However, no effective treatment strategies are available for binge drinking induced AF due to the unknown underlying mechanisms. In this thesis, I aim to elucidate the mechanisms of binge alcohol-promoted atrial arrhythmogenicity by using a mouse model of repeated binge alcohol exposure established in the Ai Lab.

The Ai …

The Amino Terminal Region Of Cardiac Myosin Binding Protein-C Is Necessary For Cardiac Function, Thomas Lawrence Lynch

Dissertations

Cardiac myosin binding protein-C (cMyBP-C) is a thick filament-associated protein that has been suggested to regulate cardiac contraction via its amino terminal (N’) region. Following ischemic injury to the heart, cMyBP-C is cleaved into a predominant N’ fragment consisting of domains C0 through C1 and the first 17 residues of the M-domain that is referred to as C0-C1f. However, the necessity of the N’-C0-C1f region of cMyBP-C in regulating cardiac function in vivo has not been elucidated. I hypothesized that the N’-C0-C1f region of cMyBP-C is critical for normal cardiac function in vivo. To test this hypothesis, transgenic (TG) mice …

Inhibition Of B Lymphopoiesis By Adipocytes And Myeloid-Derived Suppressor Cells, Domenick Kennedy

Dissertations

B lymphopoiesis declines with age in humans, mice, and rabbits. Impaired B lymphopoiesis correlates with increased fat in the bone marrow (BM), suggesting that adipocytes negatively regulate this process. In fact, adipocyte factors were found to inhibit B cell development in BM cultures.

Our goal was to understand the mechanism by which adipocytes inhibit B cell development. Through culturing mouse BM cells on OP9 stromal cells in the presence of adipocyte-conditioned medium (ACM), we found that adipocytes promote the accumulation of CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs). These cells were not simply bystanders, as we report for the first time that …

Mechanism By Which Commensal Bacteria Limit Inflammation, Mallory Paynich

Dissertations

Trillions of bacteria live within the gastrointestinal tract and are critical for maintaining intestinal homeostasis; however, the mechanisms utilized by specific bacterial molecules to contribute to homeostasis are not well understood. We utilize a mouse model in which a single oral dose of the probiotic, Bacillus subtilis, protects mice from acute colitis induced by the enteric pathogen Citrobacter rodentium. Our goal is to elucidate the mechanism by which B. subtilis prevents inflammation.

We identified exopolysaccharides (EPS) to be the active molecule of B. subtilis, and a single dose of EPS protects mice from disease. EPS binds F4/80+CD11b+ peritoneal macrophages, and …

Monocyte-Induced Regulatory T Cell Differentiation, Jessica Genevieve Lee

Dissertations

Immediately after birth, thousands of foreign antigens challenge the newborn immune system. Many of the invaders are harmless, such as food, pollen, and beneficial bacteria. Newborns have a tolerant immune system that keeps them from developing inflammation or allergies to these new antigens. In utero, this immunoregulatory tendency is important for establishing tolerance to self and maternal antigens. Multiple processes contribute to fetal tolerance, including clonal deletion, anergy, changes in antigen presenting cells (APCs), and the generation of regulatory T cells (Tregs). However, the mechanism(s) of fetal Treg differentiation and the specific APCs required are unknown.

Our lab has previously …

Adenovirus Evasion Of Cell-Intrinsic Immunity, Andrew Michael Burrage

Dissertations

Virus cell entry represents one of the earliest opportunities for a host to respond to infection. Understanding the processes of pathogen detection and restriction employed by the host, as well as strategies utilized by the virus itself to evade such processes, is critical in developing therapeutics to counter pathogenesis. Adenovirus (Ad) infections are self-limiting in healthy populations, but can be devastating to individuals with compromised immune systems. Currently, no specific antiviral treatments exist to combat Ad infections in susceptible populations. However, because Ad infections are not severe in healthy individuals, employing replication-defective Ads as vaccine vectors is generally regarded as …

Regulation Of The Subunits Of Hypoxia Inducible Factors By Sprouty2 And Its Impact On Different Biological Processes, Kristin Caroline Hicks

Dissertations

The hypoxia inducible factors (HIF1α, HIF2α, HIF1β) promote transcription of genes that regulate glycolysis and cell survival and growth. Sprouty2 (Spry2) is a modulator of receptor tyrosine kinase signaling and inhibits cell proliferation via different mechanisms. Because of the seemingly opposite actions of the HIF and Spry2 on cellular processes, we hypothesized that Spry2 decreases the protein levels of HIF1α, HIF2α and HIF1β by enhancing the proximity of the HIF subunit to an ubiquitin ligase capable of degrading the subunit. Focusing on HIF1α as a prototypical alpha subunit, in a variety of tumor derived cell lines, Spry2 decreases the protein …

Studies Into The Allosteric Regulation Of Adp-Glucose Pyrophosphorylases, Benjamin Luke Hill

Dissertations

The synthesis of glycogen in bacteria and starch in plants is allosterically controlled by the production of ADP-glucose by ADP-glucose pyrophosphorylase. Using computational studies, site directed mutagenesis, and kinetic characterization, and protein crystallography we found a critical region for transmitting the allosteric signal in the Escherichia coli and A. tumefaciens ADP-glucose pyrophosphorylase. Molecular dynamics simulations and structural comparisons with other ADP-glucose pyrophosphorylases provided information to hypothesize communication pathways that link allosteric and active sites, and this was tested by site-directed mutagenesis and kinetic characterization of the mutant enzymes. In addition, the application of x-ray crystallography enabled the pinpointing of the …

Heart And Sole: The Functional Role Of Fast-Skeletal Myosin Binding Protein-C In Cardiac And Skeletal Muscle, Brian Leei Lin

Dissertations

The goal of my dissertation was to compare and contrast the function of all three major isoforms of Myosin Binding Protein-C (MyBP-C): slow-skeletal, fast-skeletal, and cardiac (ssMyBP-C, fsMyBP-C, and cMyBP-C, respectively), with a focus on the least characterized isoform, fsMyBP-C. Using a variety of ex vivo, in vitro, and in silico methods, my research demonstrated that the N-terminal region of all MyBP-C isoforms bind to actin and shift tropomyosin, thus activating the thin filament during contraction. Furthermore, each isoform differentially activated the thin filament over isoform-specific ranges of Ca2+: slow-skeletal activates at low Ca2+, fast-skeletal activates at higher Ca2+, and …

The Impact Of Altered T Cell Receptor—Peptide-Major Histocompatibility Complex Interactions On Antigen Recognition And T Cell Function, Timothy T. Spear

Dissertations

Adoptive cell transfer (ACT) using T cell receptor (TCR) gene-modified T cells is an exciting and rapidly evolving field. Numerous basic science and clinical studies have demonstrated various levels of feasibility, safety, and efficacy using TCR-engineered T cells to treat cancer and viral infections. Genomic instability of targeted diseases, however, requires effective and safe TCRs to cross-recognize mutated antigens while minimizing on- or off-target toxicities. Thus, improvements to T cell-based therapeutics mandate a broader understanding of the principles governing antigen recognition. This dissertation addresses critical biologic questions evaluating which parameters are most important in facilitating antigen recognition, and how alterations …

Development Of "Inside-Out" Pegylated Crosslinked Hemoglobin Polymers: Novel Hemoglobin-Based Oxygen Carriers (Hboc), Kyle Douglas Webster

Dissertations

The development of an effective blood substitute is urgent due to increasingly common blood shortages, the need to type-match donated blood, and communicable diseases (e.g. HIV) posing risks for blood transfusions around the world. There have been many attempts at creating hemoglobin-based oxygen carriers (HBOC) using a variety of techniques centered around the use of polyethylene glycol (PEG) conjugated to hemoglobin (Hb) tetramers. A novel method, “Inside-Out” PEGylation, has been developed by our lab to produce a polyethylene glycol crosslinked hemoglobin (PEG XL-Hb) polymer. This method utilizes a single PEG backbone that is surrounded by multiple proteins, instead of covering …

The Role Of Foxo Transcription Factors In Alcohol-Induced Deficient Fracture Repair, Philip M. Roper

Dissertations

Proper and complete repair of a bone fracture is essential in quality of life maintenance, but poor healing and fracture malunion are still medically and socially relevant problems. Alcohol abuse impairs normal fracture healing, leading to delayed or incomplete union. This dissertation aims to clarify mechanisms behind this alcohol-induced impaired healing, thereby elucidating potential methods of intervention.

Alcohol-induced oxidative stress has been linked to many morbidities associated with alcohol abuse. This dissertation elucidates a potential mechanism through which alcohol inhibits fracture healing by increasing oxidative stress. Using a rodent model, I found that alcohol exposure decreases fracture callus formation and …

Mechanistic Variations Of The Bronsted Linear Free Energy Relationships For Nonezymatic Nucleotidyl Transfer Reactions, Zheng Zhang

Dissertations

As the essential enzymes in human bodies, DNA polymerases play a significant role in DNA replication, repair, genetic recombination, and reverse transcription. In 1956, the enzyme of DNA polymerase I, also named as Pol I, was discovered by Arthur Kornberg and colleagues. Subsequently, the Noble Committee had decided that the Noble Prize in Physiology or Medicine for 1959 was to be awarded to Kornberg for his excellent original work that describes the DNA replication process whereby the DNA polymerase copies the nucleotide sequence of a DNA template strand. Because of the complex enzyme structure in the DNA polymerase, it is …

Cardiac Calcium Atpase Dimerization Measured By Fluorescence Resonance Energy Transfer And Chemical Cross-Linking, Daniel Blackwell

Dissertations

The cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA) establishes the intracellular calcium gradient across the sarcoplasmic reticulum membrane. It has been proposed that SERCA forms homo-oligomers that increase the catalytic rate of calcium transport. We investigated SERCA oligomerization in rabbit left ventricular myocytes using a photoactivatable cross-linker. Western blotting of cross-linked SERCA revealed higher molecular weight species consistent with SERCA oligomerization. Fluorescence resonance energy transfer (FRET) measurements in cells transiently transfected with fluorescently-labeled SERCA2a revealed that SERCA readily forms homo-dimers. These dimers formed in the absence or presence of the SERCA regulatory partner, phospholamban (PLB) and were unaltered by PLB phosphorylation …

The Role Of Microrna In Cardioprotection: Ischemic Preconditioning And Mesenchymal Stem Cell Paracrine Effects, Kristin Luther

Dissertations

Changes in gene expression and protein levels are an important aspect of cardioprotection in which short non-coding RNA known as miRNA may play a key regulatory role. We investigated the functions of several miRNAs in the context of two cardioprotective stimuli, ischemic preconditioning (IPC) and mesenchymal stem cell (MSC) paracrine effects. We hypothesized that downregulation of a set of miRNAs (miR-148a/b, miR-30b, and let-7a*) augments expression of protective heat shock proteins during IPC, and that MSC exosomes transfer miR-21 to cardiomyocytes, resulting in downregulation of pro-apoptotic genes and reduction of infarct size.

IPC increased the level of Hsp70, Hsp90, and …