Neuroscience and Neurobiology Commons^™

The Pathophysiological Mechanisms Of Alzheimer's Disease; Investigating Therapeutic Interventions For Disease Onset, Alexandra A. Sandberg

Electronic Theses and Dissertations

Alzheimer’s Disease is a multifarious disease that progressively affects more people as both the proportion of older adults in the population and life expectancy increase in both the United States and worldwide. This devastating disease is a result of rampant neuronal loss in the memory centers of the brain that robs the independence of those who are diagnosed and places a heavy burden on those who care for them. Traditionally speaking, research has focused on the hallmark pathology of amyloid plaques, targeting them to try and prevent disease onset. However, countless failures in clinical trials aimed at this said pathology …

The Role Of Vps54 In Drosophila Melanogaster Neuronal Development And Age Progressive Neurodegeneration, Emily Wilkinson

Electronic Theses and Dissertations

Vps54 is a subunit of the Golgi-associated retrograde protein (GARP) complex, which is involved in tethering endosome-derived vesicles to the trans-Golgi network (TGN). The “wobbler” mouse is the phenotypic result of a destabilizing point mutation in Vps54. This mutation causes neurodegeneration and is subsequently used as a model for human motor neuron disease. Presently, it is unclear how disruption of GARP complex function leads to motor neuron degeneration. To better understand the role of Vps54 in motor neuron development, function, and age-related neurodegeneration, we disrupted expression of the Vps54 ortholog in Drosophila and examined the impact on larval neuromuscular junction …

Characterization Of A Phosphomimetic Mutant Of The Als Associated Protein Tdp-43, Nicole Toro

Electronic Theses and Dissertations

Trans-activation response (TAR) DNA-binding protein 43 (TDP-43) is a natively dimeric 414-residue protein that is encoded by the human TARDBP gene that has important implications in the pathogenesis of the neurodegenerative disorders ALS, FTD, and CTE. TDP-43 has been found hyperphosphorylated and ubiquitinated in the aggregates of the affected neurons of these diseases. The discovery of the presence of TDP-43 positive inclusions in brain matter of patients with CTE has made repetitive brain injury a possible environmental stimulus for aggregation in TDP-43 proteinopathies. We expand upon the hypothesis that TDP-43 readily aggregates under agitation conditions and that the addition of …

Tau Aggregation, Conformational Selection, And Inhibition, Michael R. Holden

Electronic Theses and Dissertations

Tau fibrils are a pathological hallmark of over 20 neurodegenerative disorders, including Alzheimer's disease. There currently is no cure for these diseases and treatments are limited. Once Tau fibrils form in the brain, they propagate down neuronal networks, and this spreading is linked to disease progression. Studying the behavior and structure of Tau monomer and Tau aggregates therefore may give insight into methods by which the spread of Tau fibrils can be inhibited. The structures of the Tau fibrils from different diseases are thought to vary, partially giving rise to the different disease phenotypes. Tau natively binds to microtubules by …

Relationship Between Tdp-43 Toxicity And Aggregation In Saccharomyces Cerevisiae, Martin Anthony Aguilar

Electronic Theses and Dissertations

Protein aggregation and inclusion body formation are hallmarks of neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, and amyotrophic lateral sclerosis (ALS). These neurodegenerative diseases share a common pathology in that all include accumulation of insoluble protein aggregates in the brain. TAR-DNA-binding protein (TDP-43) is the major component found in the pathological inclusions of two of these diseases, ALS and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). This thesis focuses upon the biophysical basis for TDP-43 aggregation in S. cerevisiae. Current in vitro evidence indicates that TDP-43 is a natively dimeric protein and that binding to RNA inhibits aggregation. Corresponding …

Neuroprotection Comparison Of Different Nutraceutical Compounds Against Mechanistically Distinct Cell Death Inducing Agents, Faten I. Taram

Electronic Theses and Dissertations

Neurodegenerative diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), include the progressive loss of structure and function of neurons leading to neuronal death. All of these diseases are fatal, as there is no cure for them. The causes of these diseases are unknown; however, there are many proposed mechanisms that lead to neurodegenerative diseases. Oxidative stress is the leading cause of cell death in neurodegenerative diseases, in addition to other mechanisms including endoplasmic reticulum stress, proteasome inhibition, nitrosative stress, inflammation and excitotoxicity. More understanding of the death mechanisms at work in neurodegeneration is necessary to …

The Neuroprotective And Therapeutic Effects Of Anthocyanins And Their Metabolites In Vitro And In A Mouse Model Of Amyotrophic Lateral Sclerosis, Aimee Nicole Winter

Electronic Theses and Dissertations

Anthocyanins, a unique class of flavonoid compounds, have recently come to the forefront of investigative research aimed at evaluating the potential applications of natural products to human health. Evidence demonstrating the beneficial effects of anthocyanin consumption has been reported for a myriad of conditions including cancer, cardiovascular disease, and lately, neurodegenerative disease. Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS) are characterized by the death of specific neuronal populations within the brain and spinal cord, leading to cognitive and/or motor impairment. While the etiology of many of these diseases is largely unknown, several factors have …

Towards Closed-Loop Deep Brain Stimulation: Behavior Recognition From Human Stn, Soroush Niketeghad

Electronic Theses and Dissertations

Deep brain stimulation (DBS) provides significant therapeutic benefit for movement disorders such as Parkinson’s disease (PD). Current DBS devices lack real-time feedback (thus are open loop) and stimulation parameters are adjusted during scheduled visits with a clinician. A closed-loop DBS system may reduce power consumption and side effects by adjusting stimulation parameters based on patient’s behavior. Thus behavior detection is a major step in designing such systems. Various physiological signals can be used to recognize the behaviors. Subthalamic Nucleus (STN) Local field Potential (LFP) is a great candidate signal for the neural feedback, because it can be recorded from the …

The Effects Of Molecular Chaperones On Tau Fibril Assembly, Ahmed Omran

Electronic Theses and Dissertations

The accumulation of microtubule-associated protein tau into fibrillar aggregates is the hallmark of Alzheimer’s disease and other neurodegenerative disorders, collectively referred to as tauopathies. Fibrils can propagate from one cell to the next and spread throughout the brain. However, a study shows that only small aggregates can be taken up by cultured neuronal cells. The mechanisms that lead to the breakage of fibrils into smaller fragments remain unknown. In yeast, the AAA+ chaperone HSP104 processes the reactivation of protein aggregates and is responsible for fragmentation of fibrils. This study focused on investigating the effects of molecular chaperones on tau fibrils …

Rho Gtpases In Neuronal Apoptosis And Neurodegeneration, Trisha Stankiewicz

Electronic Theses and Dissertations

Several studies have identified Rho family GTPases (i.e. Rho, Rac, Cdc42) as mediators of diverse critical cellular processes, such as actin cytoskeleton remodeling, gene transcription, cell-cell adhesion, and cell cycle progression. However, more recent data highlight an essential role for Rho GTPases as regulators of neuronal morphology and neuronal survival. In particular, Rac GTPase generally induces neurite outgrowth and promotes neuronal survival while Rho GTPase typically provokes neurite retraction and induces neuronal apoptosis. However, the precise signaling pathways that regulate neuronal survival downstream of Rho GTPases and the potential involvement of dysregulated activity of Rho GTPases as a causative factor …

Seeded Propagation Of Tau Fibrils, Paul David Dinkel

Electronic Theses and Dissertations

In various neurodegenerative diseases, including Alzheimer's disease, progressive supranuclear palsy, Pick's disease, and corticobasal degeneration, the deposition of fibrils composed of misfolded tau protein is observed. Recent evidence suggests that tau fibrils transfer between cells and spread throughout the brain, underscoring the significance of fibril propagation.

Six tau isoforms exist in the adult human brain that can be grouped into 4-repeat (4R) tau and 3-repeat (3R) tau based on the presence or absence of the second of four microtubule binding repeats. We demonstrate in vitro that seeded fibril growth, a prerequisite for the spreading of the tau pathology, is crucially …

Connexin-32 And Connexin-43 Immunoreactivity In Rodent Taste Buds, Amanda E. Bond

Electronic Theses and Dissertations

Studies indicate that ATP is one of the primary neurotransmitters in taste transduction. ATP release occurs from taste cells via specific hemichannels such as pannexin/connexin hemichannels (Huang et al., 2007; Romanov et al., 2007). We hypothesize that Type II (receptor) and possibly Type III (presynaptic) cells release ATP at sites containing pannexin/connexin hemichannels. In this study, we examine the presence of connexin–32–LIR (Like Immunoreactivity) and connexin–43–LIR in rodent taste buds through immunocytochemical analysis and DAB (Di–amino–benzidine) immunoelectron microscopy. We observed that connexin–32–LIR co–localizes with P2X2–LIR in nerve fibers and in a small subset of NCAM–LIR cells. Connexin–32–LIR does not co–localize …

Nutraceutical Antioxidants And Their Therapeutic Potential In Neurodegeneration, Erika Kristine Ross

Electronic Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disease that affects motor neurons of the brain and spinal cord. Many studies indicate that mitochondrial oxidative stress (MOS) is a principal mechanism underlying the pathophysiology of this and other devastating neurodegenerative diseases. Here, we investigated a unique whey protein supplement (Immunocal®) to determine its neuroprotective efficacy in several in vitro models of MOS and in an in vivo mouse model of ALS. This non-denatured whey supplement contains cystine which is an oxidized form of cysteine, an essential precursor for synthesis of the endogenous antioxidant, glutathione (GSH). In primary cultured rat cerebellar …

Micrornas 9a, 9b, 9c And 315 Regulate Expression Of A Reporter For The Neuronal Microtubule-Associated Protein Futsch/Map1b, Leslie M. Rozeboom

Electronic Theses and Dissertations

Fragile X syndrome (FXS) is the most common form of inherited mental retardation in humans. FXS is caused by loss of the Fragile X Mental Retardation Protein (FMRP), an important regulator of neuronal mRNA translation. Patients with FXS display cognitive deficits including memory problems. Protein synthesis-dependent long-term changes in synaptic plasticity are involved in the establishment and maintenance of long-term memory. One prevalent theory of FXS pathology predicts that FMRP is required to negatively regulate the translation of important mRNAs at the synapse. We are investigating microRNAs (miRNAs) as a potential regulator of synaptic FMRP-regulated mRNAs that have previously been …

Acute Synaptic Activity Causes Differential Mirna Expression In The Drosophila Melanogaster Larval Central Nervous System, Robert Ian Sand

Electronic Theses and Dissertations

The primary goal of this thesis was to determine if spaced synaptic stimulation induced the differential expression of microRNAs (miRNAs) in the Drosophila melanogaster central nervous system (CNS). Prior to attaining this goal, we needed to identify and validate a spaced stimulation paradigm that could induce the formation of new synaptic growth at a model synapse, the larval neuromuscular junction (NMJ). Both Channelrhodopsin- and high potassium-based stimulation paradigms adapted from (Ataman, et al. 2008) were tested. Once validation of these paradigms was complete, we sought to characterize the miRNA expression profile of the larval CNS by miRNA array. Following attainment …

Neuroprotective Effects Of Anthocyanins On Neuronal Death Induced By Inhibition Of Bcl-2 And Oxidative Stress, Natalie A. Kelsey

Electronic Theses and Dissertations

Neurodegenerative diseases such as Parkinson’s and amyotrophic lateral sclerosis have devastating consequences to the afflicted patients. A major cellular pathophysiology underlying these diseases is mitochondrial oxidative stress (MOS) leading to neuronal death. Here, we investigated the neuroprotective effects of a novel class of nutraceuticals, anthocyanins, against MOS-induced death in primary cultures of rat cerebellar granule neurons (CGNs). Anthocyanins are natural antioxidants whose neuroprotective potential has yet to be examined in detail. Kuromanin and callistephin are anthocyanins derived from black rice and strawberries, respectively. Glutathione (GSH)-sensitive MOS and intrinsic apoptosis were induced in CGNs by the Bcl-2 inhibitor, HA14-1. Callistephin and …

Overexpression Of Amyloid Precursor Protein Induces Mitochondrial Oxidative Stress And Activates The Intrinsic Apoptosis Pathway, Matthew G. Bartley

Electronic Theses and Dissertations

Down syndrome (DS) is the most common genetic form of cognitive disability and is caused by trisomy of chromosome 21. Within chromosome 21 is the gene, amyloid precursor protein (APP). Proteolysis of APP into toxic and aggregate-prone, beta-amyloid fragments underlies the pathophysiology of Alzheimer's disease (AD). Individuals with DS develop the neuropathology that can be diagnosed as AD; however, the role of APP overexpression in this comorbidity is presently unclear. Here, we elucidated the mechanism of cell death induced by overexpression of wild type APP. Chinese hamster ovary cells transfected with a DsRed-APP fusion construct displayed caspase-3 activation and nuclear …