Medicine and Health Sciences Commons^™

Exploring Drivers Of Sex-Based Disparities In Relapsing Multiple Sclerosis, Stephanie K. Buxhoeveden

Theses and Dissertations

Females are three times more susceptible to relapsing multiple sclerosis (MS) and males typically have more severe disease, but the molecular underpinnings of these sex-based disease disparities are unknown and represent a critical knowledge gap.Subject Population: Blood samples from a demographically homogenous group of treatment naïve males and females with relapsing-MS and healthy controls. Research Design: Cross-sectional combinatorial omics pilot study. Instruments: Whole transcriptomic analysis with messenger RNA (mRNA) expression profiling using next generation sequencing (RNA-seq) and micro-RNA (miRNA) expression using NanoString technology. Aim 1) Identify and compare the actively expressed mRNAs in the transcriptome of males and …

Investigating The Role Of Vasopressin Receptor 1a Expressing Neurons In Mouse Dorsal Raphe, Tirth Nimishbhai Patel

Theses and Dissertations

Human social interactions heavily impact our physical and mental wellbeing. Arginine-vasopressin (Avp) and serotonin have both been implicated in modulation of social behaviors ranging from affiliation to aggression. In male mice, Avp neurons in the bed nucleus of stria terminalis (BNST) show increased activity during prosocial behavior. BNST sends Avp afferents to the dorsal raphe (DR) in the midbrain, a home to a large portion of serotonin neurons in the mouse brain. Previous data suggests that DR is activated during male prosocial behavior with a female stimulus, and Avp indirectly excites serotonin neurons. We hypothesized that DR contains a population …

A Preliminary Investigation Of Neuroantibody Levels, Prevalence, And Environmental Factors In Patients With Neurological Dysfunction, Jihan Azar

Theses and Dissertations

Nervous system damage comprises a large proportion of diseases worldwide. It is also the most difficult to diagnose. Biomarkers for nervous system damage are needed in order to diagnose these diseases early enough to allow for intervention. In this study, we recruited patients from two Egyptian hospitals with MCI, ET and NMS and health references. Serum autoantibody levels against neural proteins and heavy metals were analyzed and compared. Immunoglobulin G (IgG) antibodies against neurofilament H (NFH), Glial Fibrillary Acidic Protein (GFAP), Myelin Basic Protein (MBP) and alpha synuclein (a-SYN) and Immunoglobulin M (IgM) antibody against neurofilament light (NFL) were among …

Selective Gsk3Β Inhibition Mediates An Nrf2-Independent Anti-Inflammatory Microglial Response, Mohamed H. Yousef

Theses and Dissertations

Glycogen Synthase Kinase 3 (GSK3) is associated with the proinflammatory phenotype of microglia and has been shown to act in concert with Nuclear factor kappa B (NF-κB). . GSK3 is also a suppressor of Nuclear factor erythroid 2-related factor 2 (Nrf2), the principal regulator of redox homeostasis. Agreeing with the oxidative paradigm of aging, Nrf2 is often deregulated in parainflammatory and neurodegenerative diseases. In this study, we aimed to explore a multimodal disease-modifying utility of GSK3 inhibition, beyond neuronal proteopathologies, Furthermore, we aimed to underscore the difference in therapeutic value between the two GSK3 paralogs by isoform-selective chemical inhibition.

The …

Theta Burst Brain Stimulation In Painful Diabetic Neuropathy Patients: Investigating Neural Mechanisms, Bhushan Thakkar

Theses and Dissertations

Chronic pain (CP) is a significant contributor to disability and disease burden globally. In 2019, approximately 50.2 million adults (20.4% of the US population) experienced chronic pain, contributing to $560-635 billion in direct medical costs. In addition, the worldwide prevalence of diabetes mellitus has reached epidemic proportions and is set to increase to 629 million by 2045. Almost 50% of patients with diabetes present with diabetic neuropathy (DN), and one in five patients with diabetes presents with painful DN (pDN) which is the most common cause of neuropathic pain (NP) in the US. Symptomatic treatment is the mainstay of management …

Relationship Between Cognitive Performance, Physical Activity, And Socio-Demographic/ Individual Characteristics Among Aging Americans, Imtiaz Masfique Dowllah

Theses and Dissertations

Despite the attenuation of association following adjustments for covariates, participants who engaged in 3–6 hr/wk of vigorous- and > 1 hr/wk of moderate-intensity PA scored significantly higher in tests that assessed executive function and processing speed domains of cognition compared to inactive peers (η2 = 0.005 & 0.007 respectively, p < 0.05). Also, after adjustment, the effects of 1–3 hr/wk of vigorous-intensity PA became trivial for the delayed recall memory domain test scores (β = 0.33; 95% CI: –0.01, 0.67; η2 = 0.002; p = 0.56). There was no clear dose-response relationship between the cognitive test scores and weekly moderate-intensity PA. Interestingly, higher handgrip strength and higher late-life body-mass-index were associated with a higher performance across all cognitive domains. Observed associations provide evidence linking habitual PA with superior cognition health among older adults. Furthermore, increased muscle strength and higher late-life adiposity may …

Modulation In Nmda Receptor Function Alleviates Safety Learning Deficit In Females Who Experienced Chronic Stress During Adolescence, Zuby C. Okafor

Theses and Dissertations

Anxiety disorders disproportionately impact women and are more prevalent in people with a history of chronic stress. Post-traumatic stress disorder (PTSD) is a type of stress and trauma-related disorder that is largely characterized by hyperarousal to fear-based cues. The inability to dissociate the fear-response from a non-threatening cue is known as impaired safety learning. Given that N-methyl-D-aspartate (NMDA) receptors are key mediators of learning behaviors, we examined the role of NMDAr function in deficient safety learning. Previous studies have shown that female rats with a history of stress have altered NMDAr gene expression and altered glutamatergic signaling; therefore, we hypothesized …

Kcc2: A Novel Therapeutic Target To Rescue Gabaergic Dysfunction And Behavioral Deficits Induced By Hiv And Opiate Use, Aaron J. Barbour

Theses and Dissertations

With adherence to combined antiretroviral therapy (cART), HIV infection can be considered a controllable chronic condition, but quality of life issues remain. The preeminent of which, HIV-associated neurocognitive disorders (HAND), encompasses an array of neurological complications and has persisted despite cART implementation. The symptoms of HAND can be exacerbated by opiate use, a common comorbidity for people infected with HIV (PWH). While neurons are not infected by HIV, they incur sublethal damage, with γ-amino butyric acid- (GABA)ergic function being particularly vulnerable to viral and inflammatory factors released by infected/affected glia. This dissertation presents studies on novel organoid and dissociated primary …

Recovery From Visual Dysfunction Following Mild Traumatic Brain Injury Is Associated With Adaptive Reorganization Of Retinal Inputs To Lateral Geniculate Nucleus In The Mouse Model Utilizing Central Fluid Percussion Injury., Vishal C. Patel

Theses and Dissertations

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality nationwide. Prevalence of mild TBI (mTBI) vastly outnumbers more severe forms however the associated morbidity has only recently gained public attention. Visual dysfunction is a significant component of mTBI associated morbidity with recovery of function linked with improvement in global outcomes. Examination of sensory and motor pathways in other brain injury paradigms support that recovery is largely dependent on adaptive plasticity of remaining connections. Current examinations of visual function recovery following mTBI is limited to identifying evidence for recovery and objective evidence for adaptive plasticity is limited. Therefore, …

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 …

The Contribution Of Sarm1 To Axonal Degeneration In Cns Inflammatory Disorders, Daniel C. Njoku

Theses and Dissertations

BACKGROUND: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that results in demyelination and axonal loss. Efficiently targeting mechanisms of axonal degeneration in MS has the potential to reduce disability but remains an unmet need. Prior research has identified the protein sterile alpha and TIR motif containing 1 (SARM1) as a critical factor that promotes axonal destruction in the program of axonal degeneration known as Wallerian degeneration. SARM1 inactivation reduces axonal degeneration in a variety of contexts including traumatic and toxic injury, but it remains unknown to what extent SARM1 is involved in axonal degeneration …

Metabotropic Glutamate Receptor 2 Activation: Computational Predictions And Experimental Validation, Amr Ellaithy

Theses and Dissertations

G protein-coupled receptors (GPCRs) are the largest family of signaling proteins in animals and represent the largest family of druggable targets in the human genome. Therefore, it is of no surprise that the molecular mechanisms of GPCR activation and signal transduction have attracted close attention for the past few decades. Several stabilizing interactions within the GPCR transmembrane (TM) domain helices regulate receptor activation. An example is a salt bridge between 2 highly conserved amino acids at the bottom of TM3 and TM6 that has been characterized for a large number of GPCRs. Through structural modeling and molecular dynamics (MD) simulations, …

Epigenetic Editing To Validate Findings From Methylome-Wide Association Studies Of Neuropsychiatric Disorders, Robin F. Chan

Theses and Dissertations

DNA methylation is necessary for learning, memory consolidation and has been implicated in a number of neuropsychiatric disorders. Obtaining high quality and comprehensive data for the three common forms of methylation in brain is challenging for methylome-wide association studies (MWAS). To address this we optimized a panel of enrichment methods for screening the brain methylome. Results show that these enrichment techniques approach the coverage and fidelity of the current gold standard bisulfite based techniques. Our MBD-based method can also be used with low amounts of genomic material from limited human biomaterials. Psychiatric disorders have high prevalence and are often chronic …

Human Neural Progenitor Cells Are Productively Infected By R5-Tropic Hiv-1: Opiate Interactions On Infection And Function Involve Cdk5 Signaling, Joyce Magat Balinang

Theses and Dissertations

Human immunodeficiency virus type 1 (HIV-1) is known to cause a spectrum of neurological, behavioral and motor deficits collectively termed as HIV-1 associated neurocognitive impairments (HAND). Opiates augment HIV-related CNS complications through both direct and indirect mechanisms that disrupt glial and neuronal function. All CNS macroglia and neurons derive from neural progenitor cells (NPCs) during development, and NPCs in the adult brain contribute to repair processes. Since disruptions in NPC function are known to impact CNS populations and brain function in a number of disease/injury conditions, we determined whether HIV ± opiate exposure affected the maturation and fate of human …

Autotaxin In Central Nervous System Development And Disease, Natalie A. Wheeler

Theses and Dissertations

During development, oligodendrocytes (OLGs), the myelinating cells of the central nervous system (CNS), undergo a stepwise progression during which OLG progenitors, specified from neural stem/progenitor cells, differentiate into fully mature myelinating OLGs. This progression along the OLG lineage is characterized by well-synchronized changes in morphology and gene expression patterns. The studies presented in this dissertation identified the extracellular factor Autotaxin (ATX) as a novel upstream signal modulating HDAC1/2 activity and gene expression in cells of the OLG lineage. Using the zebrafish as an in vivo model system, as well as rodent primary OLG cultures, this functional property of ATX was …

Post-Tbi Hippocampal Neurogenesis In Different Tbi Models, Kaushal S. Patel

Theses and Dissertations

Traumatic brain injury (TBI) leads to short-term and long-term consequences that can cause many different life-long disorders. Studies of TBI have generally focused on the acute stage; however, it is now becoming important to investigate chronic responses following TBI as clinical reports of dementia and cognitive impairments have been linked to a history of TBI. Recent data have established that cognitive function is associated with hippocampal neurogenesis. Chronic injury induced changes in the brain may affect this endogenous process. Chronic responses following TBI include cell death pathways and inflammatory responses that are persistent in the brain for months to years …

The Effects Of 7,8-Dihydroxyflavone On Hippocampal Neurogenesis Following Traumatic Brain Injury, Mary K. Wurzelmann

Theses and Dissertations

Following traumatic brain injury (TBI), the hippocampus is particularly vulnerable to damage, and BDNF, an endogenous neurotrophin that activates the TrkB receptor, has been shown to play a key role in the brain’s neuroprotective response. Activation of the TrkB signaling pathway by BDNF in the CNS promotes cell survival and aids in cell growth. However, due to its inability to cross the blood brain barrier (BBB), the therapeutic advantages of BDNF treatment following TBI are limited. 7,8-Dihydroxyflavone (7,8-DHF) is a flavonoid that mimics the effects of BDNF, is a potent TrkB receptor agonist, and can successfully cross the BBB. Our …

Potential Treatments For Malformation Associated Epilepsy, Olivia M. Bowles

Theses and Dissertations

Epilepsy has been previously attributed to either increased excitation or decreased inhibition. With this closed frame of mind, modern medicine has been unable to develop a permanent treatment against the mechanisms of epilepsy. In order to treat patients with intractable seizures, especially those caused by developmental malformations, it is essential to understand the entirety of mechanisms that could possibly play a role in the abnormal cortical function. One such developmental malformation is known as polymicrogyria. Epileptogenesis occurs in an area laterally adjacent to this malformation known as the paramicrogyral region (PMR). Past studies have narrowed down the potential cause of …

Age Related Decline In Memory: Examining The Mediation Effect Of Processing, Executive Functioning And Intelligence In Normal Adults, Jada J. Stewart

Theses and Dissertations

Multiple mediation analyses that collectively examine the prominent theories of cognitive aging (i.e., Common Cause, Processing, and Executive Decline Hypotheses) along with other cognitive domains that are sensitive to aging are rare. Moreover, having identified that cognition begins to decline as early as 30 years old, few studies have examined the mechanisms that underlie memory change among younger aging individuals. As a result, it is unclear whether relevant mediating variables have been excluded from early research on age-related memory decline, or to what extent rehabilitative strategies are applicable as early interventions for maintaining cognitive functioning into late life.

The present …

Psychoactive Synthetic Cathinones (Or 'Bath Salts'): Investigation Of Mechanisms Of Action, Farhana Sakloth

Theses and Dissertations

Synthetic cathinones represent threatening and high abuse-potential designer drugs. These are analogs of cathinone (the b-keto analog of amphetamine (AMPH)) a naturally occurring stimulant found in the plant Catha Edulis. Methcathinone (MCAT) was the first synthetic analog of cathinone to be identified in 1987 by Glennon and co-workers and it exerted its action primarily through the dopamine transporter (DAT). Most central stimulants exert their action via monomaine transporters by causing either the release (e.g. cathinone analogs such as MCAT) or by preventing the reuptake (e.g. cocaine) of the neurotransmitter dopamine (DA) thus increasing the extracellular synaptosomal concentration of this …

Effects Of Hiv-1 Tat On The Enteric Nervous, Joy Ngwainmbi

Theses and Dissertations

More than 1.2 million people are estimated to be currently living with the human immunodeficiency virus (HIV) in the United States of America. The gastrointestinal (GI) tract is both a major target and an important component of HIV pathogenesis. The GI processes that are dysregulated during HIV infection are controlled by the enteric nervous system (ENS). Indeed, both clinical and experimental studies have implicated the ENS in HIV and simian immunodeficiency virus (SIV) pathogenesis. In addition to direct viral effects, the HIV virus also indirectly affects the GI tract via cellular and/or viral toxins released by infected cells. Trans-activator of …

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 …

Effects Of Hiv-1 Viral Protein Tat On The Viability And Function Of Oligodendroglial Cells, Shiping Zou

Theses and Dissertations

Myelin pallor is frequently reported in HIV patients, and can occur in the CNS prior to other evidence of disease process. Our exploratory studies showed that oligodendrocytes (OLs) are direct targets of HIV-1 Tat (transactivator of transcription). Tat induces a dose-dependent increase of intracellular Ca²⁺ level ([Ca²⁺]_i) in cultured murine OLs, which can be attenuated by ionotropic glutamate receptor (iGluR) antagonists MK801 and CNQX. The Tat-induced [Ca²⁺]_i increase leads to increased death in immature (O4⁺, MBP^-), but not mature (O4⁺, MBP⁺) OLs, over 96 …

Axon Initial Segment Stability In Multiple Sclerosis, Suneel K. Thummala

Theses and Dissertations

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by inflammation and demyelination. In addition to these hallmark features, MS also presents with axonal pathology, which is likely responsible for the signs and symptoms of the disease. Although prominent in MS, axonal pathology is frequently considered a consequence of demyelination and not a primary event. This conclusion is consistent with demyelination inducing the loss of specific axonal domains, known as the nodes of Ranvier that are responsible for the propagation of action potentials along the axon. In contrast, we propose that axonal pathology associated with MS …

A Molecular Mechanism Regulating The Timing Of Corticogeniculate Innervation, Justin Brooks

Theses and Dissertations

Visual system development requires the formation of precise circuitry in the dorsal lateral geniculate nucleus (dLGN) of the thalamus. Although much work has examined the molecular mechanisms by which retinal axons target and form synapses in dLGN, much less is known about the mechanisms that coordinate the formation of non-retinal inputs in dLGN. These non-retinal inputs represent ~90% of the terminals that form in dLGN. Interestingly, recently reports show that the targeting and formation of retinal and non-retinal inputs are temporally orchestrated. dLGN relay neurons are first innervated by retinal axons, and it is only after retinogeniculate synapses form that …

Osteopontin Expression During The Acute Immune Response Mediates Reactive Synaptogenesis And Adaptive Outcome, Julie Chan

Theses and Dissertations

Traumatic brain injury (TBI) is a worldwide epidemic as the number of victims living with the resulting cognitive and physical impairment continues to rise, principally due to limited treatment options which fail to address its multifaceted sequelae. By approaching TBI therapy from a molecular standpoint, we have the opportunity to develop a better understanding of the mechanisms which prevent effective recovery. With this information, we can move toward the identification of novel therapeutic treatments which target specific molecules to improve patient outcome following TBI. Here, we have focused on the therapeutic potential of osteopontin (OPN), an extracellular matrix (ECM) protein …

Thc-Mediated Induction Of Δfosb And Its Modulation Of Cb1r Signaling And Adaptation, Lazenka Matthew

Theses and Dissertations

The main psychoactive and therapeutic effects of Δ9-tetrahydrocannabinol (THC) are mediated through cannabinoid type 1 receptors (CB1Rs). The therapeutic uses of THC are mitigated by the development of tolerance to these therapeutic effects, whereas tolerance does not readily develop to some of the side-effects of THC, like motor impairment and reward. The development of tolerance occurs through adaptations at CB1Rs, which include desensitization (G-protein uncoupling) and downregulation (receptor degradation). Brain region-dependent differences in THC-mediated adaptations are proposed to explain the differences in tolerance to various THC-mediated effects. These studies focused on whether ΔFosB, a stable transcription factor, could regulate CB1R …

Diffuse Traumatic Axonal Injury Within The Visual System: Implications For Visual Pathway Reorganization, Jiaqiong Wang

Theses and Dissertations

Traumatic brain injury is a major health problem with much of its morbidity associated with traumatic axonal injury (TAI). To date, significant insight has been gained into the initiating pathogenesis of TAI. However, the specific anterograde and retrograde sequelae of TAI are poorly understood because the diffuse nature of TAI complicates data analysis. To overcome this limitation, we subjected transgenic mice expressing yellow fluorescent protein (YFP) within the visual system to central fluid percussion injury, and consistently generated diffuse TAI within the optic nerve that could easily be followed in the organized YFP positive fibers. We demonstrated progressive axonal swelling, …

Unique Features And Neuronal Properties In A Multisensory Cortex, W. Alex Foxworthy

Theses and Dissertations

UNIQUE FEAUTRES OF ORGANIZATION AND NEURONAL PROPERTIES IN A MULTISENSORY CORTEX Multisensory processing is a ubiquitous sensory effect that underlies a wide variety of behaviors, such as detection and orientation, as well as perceptual phenomena from speech comprehension to binding. Such multisensory perceptual effects are presumed to be based in cortex, especially within areas known to contain multisensory neurons. However, unlike their lower-level/primary sensory cortical counterparts, little is known about the connectional, functional and laminar organization of higher-level multisensory cortex. Therefore, to examine the fundamental features of neuronal processing and organization in the multisensory cortical area of the posterior parietal …

Overexpression Of Serum Response Factor In Astrocytes Improves Neuronal Plasticity In A Model Of Fetal Alcohol Spectrum Disorders, Arco P. Paul

Theses and Dissertations

Neuronal plasticity deficits underlie many of the neurobehavioral problems seen in Fetal Alcohol Spectrum Disorders (FASD). Recently, we showed that third trimester alcohol exposure lead to a persistent disruption in ocular dominance (OD) plasticity. For instance, few days of monocular deprivation results in a robust reduction of cortical regions responsive to the deprived eye in normal animals, but not in ferrets exposed early to alcohol. This plasticity deficit can be reversed if alcohol-exposed animals are treated with a phosphodiesterase type 1 (PDE1) inhibitor during the period of monocular deprivation. PDE1 inhibition can increase cAMP and cGMP levels, activating transcription factors …