Molecular and Cellular Neuroscience Commons^™

Metoprolol Disrupts Sterol Biosynthesis Through Inhibition Of 7-Dehydrocholesterol Reductase (Dhcr7), Luke B. Allen

Theses & Dissertations

Cholesterol is essential for life. It is particularly important in the brain as it relies on de novo synthesis of cholesterol following the formation of the blood brain barrier (BBB). As such, disrupting sterol biosynthesis during neurodevelopment can have devastating outcomes. The most common post-lanosterol sterol biosynthesis disorder, Smith-Lemli-Opitz Syndrome, arises from a faulty DHCR7 enzyme. DHCR7 has also been shown to be inhibited by several psychotropic medications. Here we assess six beta-blockers and their effects on sterol biosynthesis in vitro. Two beta-blockers, metoprolol and nebivolol strongly inhibit DHCR7 in four separate in vitro models of both mouse and …

The Role Of Parkin In Mitochondrial Dna, Eliezer Lichter

Theses & Dissertations

Mitochondria are at the center of biological phenomena such as aging and diseases, especially neurodegenerative diseases. While the discovery of mitochondria only came approximately 200 years after the cell was discovered, a lot of progress has been made since. The mitochondrial genome encodes proteins vital for mitochondrial function. These proteins are only a subset of the proteins present in mitochondria; the rest are nuclear encoded. The nucleus also encodes cytosolic proteins vital for mitochondrial maintenance. One of these is Parkin, an E3 ubiquitin ligase that ubiquitinates mitochondrial proteins as mitochondria become depolarized. Its activity has been shown to be involved …

Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale

Electronic Theses and Dissertations

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic …

Med12 Is A Critical Regulator Of Neural Crest Lineage And Nervous System Myelination, Fatma Betul Aksoy Yasar

Dissertations & Theses (Open Access)

The Mediator complex (MED) is a multi-subunit protein complex integral to the eukaryotic transcription machinery. MED12 is a Cdk8- regulatory kinase module subunit directly implicated in human disease and is genetically altered in neurological disease and cancer. Numerous attempts at generating an in vivo system to study the role of Med12 failed due to embryonic lethality associated with germline or developmental disruption of Med12 gene. To understand the cellular and molecular processes associated with its role in disease, we generated multiple mouse models with targeted depletion of MED12 in distinct cellular lineages. Our genetically engineered models with induced and conditional …

Anatomical Analysis Of Olfactory Sensory Neuron Regeneration Via Glomerular Synaptic Activity Markers In Adult Mice, William Wamack

Undergraduate Honors Theses

The olfactory system is a great model for studying regeneration due to the olfactory epithelium’s regenerative capability which makes it a potential a source of neural stem cells. The olfactory epithelium presents three types of cells: sustentacular cells which provide support and act as glial supporting cells; olfactory sensory neurons that are in charge of detecting odorant molecules in the air; and the stem cells that generated the aforementioned cell types. Olfactory sensory neurons are constantly dying and being replaced by new neurons originating from the stem cells that lie at the base of the olfactory epithelium. We have used …

Chemosensory Receptors In Berghia Stephanieae: Bioinformatics And Localization, Kelsi L. Watkins

Masters Theses

Chemosensation is achieved through the binding of chemical signals to chemoreceptor proteins embedded in the membranes of sensory neurons. The molecular identity of these receptors, as well as the downstream processing of chemosensory signals, has been well studied in arthropods and vertebrates. However, very little is known about molluscan chemosensation. The identity of chemoreceptor proteins in the nudibranch mollusc Berghia stephanieae are unknown. Data from other protostome and molluscan studies suggest Berghia may use ionotropic receptors for some forms of chemoreception. This study used a bioinformatics approach to identify potential chemosensory ionotropic receptors in the transcriptome of Berghia. A …

Clustered Protocadherins Ubiquitination And Phosphorylation Regulates Surface Expression, Albert Ptashnik

Dissertations, Theses, and Capstone Projects

Clustered protocadherins (Pcdhs) are a family of 60 adhesion-like molecules forming a neural barcode. In vertebrate neurons, 60 Pcdhs are coded by a large gene cluster. Numerous axons in the cluster are coding for the different extracellular, transmembrane, variable portion of the cytoplasmic and constant cytoplasmic domains where their expression is controlled epigenetically. These proteins mediate interactions between axons, dendrites, and glial cells during neural development. Yet, Pcdhs are not strictly adhesion molecules. In the amacrine cells of the retina, Pcdhs promote avoidance of the same cell dendrites, where in the cortex Pcdhs promote interactions between dendrites and astrocytes. In …

Mechanism Of Tau Propagation: Putative Therapeutic Approaches, Viktoriya Morozova

Dissertations, Theses, and Capstone Projects

One of the characteristics of Alzheimer’s disease and associated tauopathies is the accumulation and aggregation of hyperphosphorylated tau protein. The biological activity of tau is to bind to tubulin and promote its assembly into microtubules with subsequent stabilization of the latter. When tau gets hyperphosphorylated it cannot bind to tubulin and carry on its function, instead, it binds to normal tau and sequesters it from microtubules leading to disruption of microtubular assembly and ultimately to the death of neurons. Our lab had previously shown that tau phosphorylation sites 199, 212, 231, and 262, combined with the FTDP-17 mutation R406W (Pathological …

Role Of Nuclear Lamins In Oligodendrocyte Lineage Cells, Camila Yattah

Dissertations, Theses, and Capstone Projects

Differentiation of oligodendrocytes from progenitor cells is a highly regulated process characterized by a series of molecular changes, resulting in nuclear and morphological features unique to the mature oligodendrocyte state. Heterochromatin formation starting at the nuclear periphery, as well as increased nuclear rigidity are characteristically observed. The nuclear periphery is characterized by the presence of the nuclear lamina and it has been implicated in higher-order genome organization in cells. Lamins are the protein components of the nuclear lamina, and their expression is dependent upon the cell differentiation stage of the cells. While Lamin B1 (LMNB1) expression is high in progenitors …

Novel Therapeutic Strategies For Alzheimer’S Disease: Prostaglandin D2 Signaling And Its Human Polymorphisms As Well As A Polypharmacological Approach, Charles H. Wallace

Dissertations, Theses, and Capstone Projects

Alzheimer’s disease (AD) is an age related neurodegenerative disease with pathology that includes amyloid plaques, neurofibrillary tangles and non-resolving neuroinflammation. Non-resolving neuroinflammation lasts the entire course of the disease and has deleterious effects and is often thought to accelerate AD pathology. Non-Steroidal Anti-inflammatory Drugs (NSAIDs) have commonly been used as therapeutics to treat pain, inflammation and vascular. NSAIDs work by altering the cyclooxygenase (COX) mediated biosynthesis of prostaglandins which are lipid mediators that have many physiological functions, for example nociception, inflammation and vasodilation. Epidemiological studies support the notion that NSAIDs could be used to treat AD. Yet, clinical trials using …

Development And Characterization Of A Novel, Genetically- Encoded Sensor To Image Sonic Hedgehog Signaling In Functional Circuits, Sonia Bernal

Dissertations, Theses, and Capstone Projects

Dynamic neurotransmitter and neuromodulator signaling in functional circuits is the neural substrate of animal behavior and cognition. The study of said circuits requires tools with sufficient spatiotemporal dynamics that can probe complex signaling patterns and decode their functional relevance by coupling the signal to behavioral output, ideally in awake, behaving animals. Much is known about the role of classical neurotransmitters such as dopamine in behavior, but a wide variety of peptides and small molecules also regulate neuronal transmission. One of these is Shh, whose presence has been observed in a variety of brain regions known to modulate movement, perception, and …

Role Of The G Protein Beta Gamma Subunits In Serotonin Transporter Dynamics, Nora Awadallah

Dissertations, Theses, and Capstone Projects

Serotonin is a vital neurotransmitter and hormone with significant roles in almost every organ system. In the central nervous system, serotonin mediates physiological functions that in turn guide behavior and mood. Here, serotonin is released from serotonergic neurons and exerts its effects through serotonin receptors. Regulation of serotonin neurotransmission is important for the maintenance of its physiological functions; thus, extracellular serotonin must be sequestered to limit the intensity and duration of serotonin transmission. Disproportionate transmission is strongly linked with neurological and psychiatric ailments.

Extracellular serotonin levels are primarily mediated by the serotonin transporter (SERT), a critically important plasma membrane protein …

Telomerase Reverse Transcriptase Marks A Novel Population Of Adult Stem Cells In The Mouse Brain That Respond To Metabolic Interventions By Modulating Adult Brain Plasticity, Gabriel S. Jensen

Electronic Theses and Dissertations

Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (qASC) in numerous adult murine and human tissues but has never been explored in the adult brain. Here, these data demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent qASCs. TERT+ cells were localized to numerous classical neuro/gliogenic niches including the ventricular-subventricular zone, hypothalamus and olfactory bulb, as well as newly discovered regions of adult tissue plasticity such as the meninges and choroid plexus. TERT+ cells expressed neural stem cell markers such as Nestin and Sox2, but not markers of activated stem/progenitor cells, …

Genetic Determinants Of Primary Nociceptor Sensitivity In Drosophila Melanogaster, Christine Hale

Electronic Theses and Dissertations

Abnormal pain affects ~50 million adults nationwide. With many of the current treatment options for chronic pain, such as opioid analgesics, carrying side effects such as the threat for addiction, research into safer and more effective options for chronic pain relief is crucial. Abnormal alterations in nociceptive sensitivity, which is the sensitivity of peripheral sensory neurons that detect noxious stimuli, can underlie, and perpetuate chronic pain. However, much is still unknown about the mechanism of how these abnormal alterations in sensitivity occur. To help elucidate genetic components controlling nociceptive sensitivity, the Drosophila melanogaster larval nociception model has been used …

Neural Stem Cells: Age-Dependent Outcomes During Viral Infections In The Central Nervous System, Manisha N. Chandwani

Electronic Theses and Dissertations

Viral infections in the central nervous system (CNS) are associated with neurodevelopmental and neurobehavioral deficits. The outcomes of viral infections can be driven by damage and death of neurons. Neural stem cells (NSCs) play key roles in neurodevelopment, repair, and physiological brain function. During a viral infection, NSC activity can disturbed by direct infection of NSCs by the virus or by anti-viral immune response. Here, we aimed to assess whether the anti-viral immune response can impact NSC activity during an immunocompetent response in the adult brain. We utilized a transgenic mouse model of Measles virus infection where only the CNS …

The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills

Graduate Theses and Dissertations

Alzheimer’s disease and related dementia (ADRD) rates are expected to triple by the year 2050. Early detection and specific mitigation efforts are warranted to blunt the alarming rate. Physical function (PF) declines with age, but higher physical function is associated with better cognitive functioning in middle-to- older age individuals. Moreover, greater physical activity (PA) is associated with better global cognition; however, Apoliporotein e4 carriers may not gain the same benefits with exercise. Additionally, plasma phosphorylated tau 217 (p-tau217) has been identified as a novel diagnostic ADRD biomarker which needs further research to examine associations with risk factors. Therefore, the aims …

Analysis Of The Distributed Representation Of Operant Memory In Aplysia, Renan Murillo Costa

Dissertations & Theses (Open Access)

Operant conditioning, a ubiquitous form of learning in which animals learn from the consequences of behavior, engages a high-dimensional neuronal population space spanning multiple brain regions. A complete characterization of an operant memory remains elusive. Some sites of plasticity participating in the engram underlying an example of operant memory in Aplysia have been previously uncovered. Three studies are described here that sought to draw closer to a thorough characterization of this memory. The first study used a computational model to examine the ways in which sites of plasticity (individually and in combination) contribute to memory expression. Each site of plasticity …

Neural Circuitry Of The Midbrain Pedunculopontine Tegmental Nucleus Regarding Its Role In Sensorimotor Gating, Niveen Fulcher

Electronic Thesis and Dissertation Repository

The brain is a complicated structure that receives copious amounts of information at any given time. The pedunculopontine tegmental nucleus (PPTg) is involved in many innate functions like arousal, rapid eye-movement (REM) sleep, reward association and sensorimotor gating. Although commonly referred to as a cholinergic structure, it also contains glutamatergic and GABAergic neurons. Based on chronic PPTg lesions that disrupted PPI, cholinergic PPTg neurons were long assumed to mediate prepulse inhibition (PPI) of startle, a measure of sensorimotor gating. Deficits of PPI are observed in a variety of neurological disorders, including Autism Spectrum Disorder (ASD), Obsessive-Compulsive Disorder (OCD), and is …

Chloride Channels That Mediate A Transient Nitric Oxide-Dependent Synaptic Polarity Switch In Retinal Amacrine Cells., Tyler Christopher Rodriguez

LSU Doctoral Dissertations

Cytosolic chloride (Cl^-) concentration determines whether GABAergic and glycinergic synapses are inhibitory or excitatory. Ionotropic GABA and glycine receptors passively conduct Cl­^- leading to membrane depolarization or hyperpolarization depending on the Cl^- equilibrium potential. Accordingly, the distribution of Cl^- across the plasma membrane has the potential to determine the properties of networks of retinal amacrine cells (ACs) and their postsynaptic partners. Ion channels are responsible for establishing Cl^- reversal potential. Nitric oxide (NO) is a signaling molecule that can be generated in the inner retina where ACs form synapses. We have shown that NO …

Genetic Heterogeneity In Schizophrenia And Contribution Of Context To Vowel Recognition, Eva Childers

Dartmouth College Ph.D Dissertations

This dissertation is composed of three chapters that address two distinct topics. Chapter 2 addresses the use of consonantal context in vowel perception. Previous studies have demonstrated that context is important for vowel identification, however, this effect may be an artifact of stimuli production. To address this potential confound, we used stimuli extracted from an audiobook and asked subjects to identify vowels encased in consonants and isolated by themselves. We show that subjects had improved vowel identification when the vowel is presented with a consonantal framing, suggesting there is information contained in the surrounding context that is important for phoneme …

Mirnas Levels In A Streptozocin Model Of Alzheimer’S Disease, Nada Moustafa

Theses and Dissertations

Dementia entails a progressive decrease in cognitive functions, with 50%-75% of cases attributed to Alzheimer’s disease (AD); an aging-associated condition characterized by the build-up of tangled phosphorylated Tau (p-Tau) protein and beta-amyloid (Aβ) depositions. Sporadic AD (sAD) is multifactorial in nature, resulting from a combination of environmental and genetic predisposing factors. Type 2 diabetes mellitus (T2DM) is a leading risk factor for dementia, and deregulation of brain glucose metabolism is associated with early cognitive affection in sAD. Thus, the diabetogenic agent Streptozotocin (STZ) is used to experimentally create an AD model in animals (STZ-induced sAD), in which abnormalities in cerebral …

Cortisol Receptor Sensitivity As A Risk Factor For Depression, Michela Michielli

Honors Theses

In 2020, the World Health Organization reported over 264 million people across the world were suffering from depression. Studies have demonstrated that one source of depression is a hormonal imbalance involved in the stress response. Cortisol is a stress hormone regulated by the Hypothalamic-Anterior-Pituitary (HPA) Axis. Its effects on the stress response and other metabolic activities in the body are exerted through the glucocorticoid and mineralocorticoid receptors (GR and MR respectively).

Our research has examined mutations known as single-nucleotide-polymorphisms (SNPs) relating to cortisol-receptor sensitivity and the behavior of cortisol in the body to investigate the link between cortisol activity and …

Genetic Circadian Mosaics And The Clock Network’S Contributions To Sleep, Lukasz Widziszewski

Dissertations, Theses, and Capstone Projects

Circadian rhythms are physiological and behavioral changes which follow a 24-hour cycle. Drosophila Melanogaster’s circadian clock neuronal network (CCNN) has been identified and several subpopulations have been characterized based on previous studies; the classifications of subpopulations of neurons within the CCNN are based on a return of anticipatory locomotor activity preceding the two daily light transitions (Lights on = dawn/Lights off = dusk). The neurons responsible for the return of anticipatory morning locomotor activity have been referred to as the M-cells, the group of neurons known to rescue evening anticipatory locomotor activity have been termed the E-cells. In this …

Withdrawal From Voluntary Oral Methamphetamine Reveals Female Specific Susceptibilities To Behavioral Deficits And Neurochemical Perpetuators Of Neurotoxicity And Drug Seeking Behavior, Nicoletta K. Memos

Dissertations, Theses, and Capstone Projects

MA is a potent, highly addictive psychomotor stimulant known to produce neurotoxic effects on the brain leading to neurological impairments^1-6 characterized by neurodegeneration of dopaminergic fibers, cell bodies and pathways, as well as brain regions such as the hippocampus, frontal cortex, and midbrain^1,5.

In MA addiction, women are more vulnerable to the behavioral and cognitive effects of MA compared to men. Adult human literature reveals gender differences in usage patterns and women demonstrate increased vulnerability to the neurotoxic effects and health effects of MA use. Women begin drug use at an earlier age, escalate drug use quicker, …

Sex-Specific Effects Of Chaperone And Glial Defenses On Experimental Lewy Body Disease, Tarun Bhatia

Electronic Theses and Dissertations

Lewy body disorders are a group of neurodegenerative conditions characterized by the pathological misfolding and aggregation of the abundant protein, α-synuclein. The most common Lewy body disorders are Parkinson’s disease and dementia with Lewy bodies. Apart from ageing, male sex is a major risk factor for Lewy body disorders, as men are at ~1.5-fold higher risk for these diseases than women. Yet, preclinical studies on Lewy body disorders rarely examine sex as a biological variable, and the mechanisms underlying sex-skewedness in disease risk remain undetermined.

Here, we developed a sex-stratified model of Lewy body disorders by exposing primary neurons harvested …

Investigating The Neuroprotective Effects Of Cannabinoids And Insulin-Like Growth Factors On Glia With Induced Inflammation, Caleb Bloodworth

Honors Theses

Chronic inflammation is a driver of numerous neurodegenerative diseases that reduce quality of life for affected individuals. Non-psychoactive cannabinoids have begun to gain more interest in the world of anti-inflammatory medicine for chronically ill patients. Along with these cannabinoids, insulin-like growth factor-1 has been examined for its association with downregulation of inflammation. Our research aimed to investigate how neuroglia are affected by treatment with cannabinoids or IGF-1 in the face of inflammation from HIV-1 protein, Tat, or lipopolysaccharide (LPS). Preliminary studies in our laboratory showed that neither cannabinoids or IGF-1 treatment altered astrocyte morphology or overall astrocyte viability under baseline …

Innate Immunity In The Pathobiology And Treatment Of Infectious And Neurodegenerative Diseases, Mai Mostafa

Theses & Dissertations

Mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells) are the governors of innate immunity which is the body’s first line of defense against microbial pathogens. They act beneficial or detrimental. They are crucial for an effective non-specific immune response to invading pathogens by engulfing, destroying, then eliciting an adaptive specific immune response. Given their pivotal functions in the host immune defense, studying MP immune responses in disease is paramount important for understanding disease pathobiology and uncovering therapeutic strategies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the driver of acute respiratory distress syndrome (ARDS) in coronavirus disease 2019 (COVID-19) amongst …

Efficacy Of Δ-9-Tetrahydrocannabinol For Hiv-Related Neuropathic Pain, Kaia Horne

Honors Theses

Despite the availability and success of antiretroviral therapeutics, ~30% of patients living with HIV experience neuropathic pain that is often intractable. The mechanisms are not known, but there is evidence to support a role for the HIV virotoxins, Tat and/or gp120, which can damage or degenerate neurons and peripheral nerves. One mechanism by which Tat and gp120 promote nerve damage involves the stimulation of proinflammatory cytokine production from immune cells which can damage or kill bystander cells. Notably, compounds found in Cannabis exert anti-inflammatory effects and many studies report HIV patients to consume more marijuana than seronegative individuals. When people …

Innate Lymphoid Cell Characterization And Ilc2s In Neuroinflammation In Aging And Sex Differences, Alexis Mobley, Alexis S. Mobley

Dissertations & Theses (Open Access)

Aging affects immunologic responses by a global immune system suppression, including dysregulation of cytokine mediators, leading to increased inflammation throughout all systems, termed inflammaging. However, understanding healthy aging mechanisms can bypass this effect. Inflammaging also leads to poor outcomes during brain injury, making immune-targeting therapeutics tantamount to overall brain health and longevity. Moreover, sex affects disease etiology and severity through hormonal and chromosomal sex, as the X chromosome contains most immunology-based genes. Androgens have a generally suppressive effect on the immune system. Additionally, when immune responses are mounted, males are better at CD4+ T cell type (Th1) responses, while females …

Hypocretin-Receptor Mrna Expression In The Central Amygdala Of Alcohol-Dependent And Non-Dependent Rats, Gabriel Aldridge

Electronic Theses and Dissertations

Hypocretin/Orexin (HCRT) neurotransmission facilitates drug-seeking behavior. HCRT neurotransmission at HCRT-receptors 1 and 2 (HCRT-R1 and -R2, respectively) is implicated in addiction. During the shift to alcohol-dependency, adaptations in neurotransmitter systems occur in reward- and stress-related brain regions. Specifically, neurotransmission systems in the central amygdala (CeA) are modulated by alcohol drinking/exposure. Therefore, this study investigated Hcrtr1 and Hcrtr2 mRNA expression in the CeA of alcohol-dependent rats and in non-dependent controls during acute alcohol withdrawal. Fos mRNA expression in the CeA of alcohol-dependent and non-dependent rats was also determined to assess adaptations in neuronal activation. To our knowledge, this is the first …