Molecular and Cellular Neuroscience Commons^™

The Role Of Spreading Depolarizations In Mild Traumatic Brain Injuries, Natalie J. Pinkowski

Biomedical Sciences ETDs

Mild traumatic brain injuries (mTBIs) often lead to acute symptoms like disorientation and discoordination, but the underlying mechanisms are unknown. Although most patients recover quickly from a single mTBI, repeated injuries can be debilitating. After an mTBI, a neurometabolic cascade produces metabolic burden and vulnerability. Spreading depolarizations (SDs) have been observed after mTBIs. Here we investigated SDs’ role in short-term motor behavioral deficits post-mTBI. We hypothesized that SDs contribute to the deficits, and exacerbated symptoms after repeated mTBIs. To test this, we used acute motor behavioral tests and long-term behavioral and cognitive tests after initiating SDs by mTBI, chemical, or …

In Silico Identification Of Small Molecule Agonist Binding Sites On Kcc2, Kenyon Mitchell, Alfred Amendolara, Ruth Hunter, Jaden Miner, Andrew Payne

Annual Research Symposium

Purpose: Potassium-Chloride Cotransporter 2 (KCC2) is a neuronal membrane protein specific to the central nervous system. It is responsible for removing Cl- ions from the intracellular space, maintaining a normal Cl- gradient essential for proper function at inhibitory synapses. Dysregulation causes an upward shift in the Cl- reversal potential resulting in a hyperexcitable state of the postsynaptic neuron. Existing literature indicates that KCC2 may be involved in the addiction pathway of a variety of drugs of abuse, including opioids and alcohol. This makes KCC2 an attractive potential drug target when treating substance use disorders. A novel direct KCC2 agonist, VU0500469, …

Dissecting The Tissue-Specific Contributions To Seizures, Cardiorespiratory Dysfunction, And Sudden Death In The Kv1.1 Mouse Model Of Epilepsy Using Conditional Knockout Approaches, Kelsey Paulhus

Biological Sciences Theses and Dissertations

Sudden unexpected death in epilepsy (SUDEP), the primary cause of mortality in epilepsy, remains poorly understood. Studies suggest seizures may trigger dangerous signals affecting the heart and lungs leading to collapse and death. The Kv1.1 deficiency mouse model mirrors clinical SUDEP cases, showing spontaneous seizures, cardiorespiratory issues, and premature death. However, this model lacks regional specificity in Kv1.1 deletion, hindering insights into SUDEP’s mechanisms and anatomical substrates.

This dissertation employs three distinct conditional knockout (cKO) techniques to investigate the individual roles for the forebrain, brainstem, and heart in SUDEP related phenotypes. The findings reveal that the forebrain alone can trigger …

The Binding And Mechanism Of A Positive Allosteric Modulator Of Kv3 Channels, Qiansheng Liang, Gamma Chi, Leonardo Cirqueira, Lianteng Zhi, Agostino Marasco, Nadia Pilati, Martin Gunthorpe, Giuseppe Alvaro, Charles Large, David Sauer, Werner Treptow, Manuel Covarrubias

Farber Institute for Neuroscience Faculty Papers

Small-molecule modulators of diverse voltage-gated K⁺ (Kv) channels may help treat a wide range of neurological disorders. However, developing effective modulators requires understanding of their mechanism of action. We apply an orthogonal approach to elucidate the mechanism of action of an imidazolidinedione derivative (AUT5), a highly selective positive allosteric modulator of Kv3.1 and Kv3.2 channels. AUT5 modulation involves positive cooperativity and preferential stabilization of the open state. The cryo-EM structure of the Kv3.1/AUT5 complex at a resolution of 2.5 Å reveals four equivalent AUT5 binding sites at the extracellular inter-subunit interface between the voltage-sensing and pore domains of the …

Exploring The Developmental Effects Of Antidepressants In Caenorhabditis Elegans, Alexandra Van Stone

Annual Research Symposium

It is so important to explore the potential side effects of antidepressants especially if these side effects could lead to a future detriment to an individual’s financial and social well-being. A better understanding of these side effects in regards to human developmental issues is imperative considering issues related to mental health and depression affect a large percentage of the population. In this study, we tested if Caenorhabditis (C.) elegans could be a potential model organism to predict possible side effects associated with select antidepressants. Their developmental problems potentially encountered upon drug treatment may be encountered in humans.

Alzheimer’S Disease And Inflammatory Biomarkers Positively Correlate In Plasma In The Uk-Adrc Cohort, Kate E. Foley, Zachary Winder, Tiffany L. Sudduth, Barbara J. Martin, Peter T. Nelson, Gregory Jicha, Jordan P. Harp, Erica M. Weekman, Donna M. Wilcock

Neurology Faculty Publications

INTRODUCTION: Protein-based plasma assays provide hope for improving accessibility and specificity of molecular diagnostics to diagnose dementia. METHODS: Plasma was obtained from participants (N = 837) in our community-based University of Kentucky Alzheimer’s Disease Research Center cohort. We evaluated six Alzheimer’s disease (AD)- and neurodegeneration-related (Aβ40, Aβ42, Aβ42/40, p- tau181, total tau, and NfLight) and five inflammatory biomarkers (TNF𝛼, IL6, IL8, IL10, and GFAP) using the SIMOA-based protein assay platform. Statistics were performed to assess correlations. RESULTS: Our large cohort reflects previous plasma biomarker findings. Relationships between biomarkers to understand AD–inflammatory biomarker correlations showed significant associations between AD and inflammatory …

Hiv-1 Mrna Knockdown With Crispr/Cas9 Enhances Neurocognitive Function, Kristen A. Mclaurin, Hailong Li, Kamel Khalili, Charles F. Mactutus, Rosemarie M. Booze

Neurology Faculty Publications

Mixed glia are infiltrated with HIV-1 virus early in the course of infection leading to the development of a persistent viral reservoir in the central nervous system. Modification of the HIV-1 genome using gene editing techniques, including CRISPR/Cas9, has shown great promise towards eliminating HIV-1 viral reservoirs; whether these techniques are capable of removing HIV-1 viral proteins from mixed glia, however, has not been systematically evaluated. Herein, the efficacy of adeno-associated virus 9 (AAV9)-CRISPR/Cas9 gene editing for eliminating HIV-1 messenger RNA (mRNA) from cortical mixed glia was evaluated in vitro and in vivo. In vitro, a within-subjects experimental design was …

Exploring A Gene Panel For Parkinson’S Disease In An Egyptian Cohort, Asmaa Saeed Gabr

Theses and Dissertations

Parkinson’s disease is a highly heterogeneous disorder characterized by diverse neuropathological features, clinical presentations and progression patterns. In Egypt, Parkinson’s disease incidence rates lie outside the range reported elsewhere. The genetic background to the pathogenesis of Parkinson's disease has been postulated for a long time. However, Parkinson’s disease has never been systematically investigated in Egypt. This study aimed to explore genetic variants and interactions that are associated with the familial and sporadic forms of Parkinson's disease in an Egyptian cohort. This includes examining variants in PD-related genes, exploring the role of specific genes like MAPT and adjacent genomic regions, and …

Methamphetamine-Induced Dna Double-Stranded Breaks: The Impact Of The Dopamine Transporter And Insights Into The Mechanisms Of Dna Damage In Mouse Neuro 2a Cells, Lizette Couto

Dissertations, Theses, and Capstone Projects

Methamphetamine (METH) abuse remains a global health concern, with emerging evidence highlighting its genotoxic potential. In the central nervous system METH enters dopaminergic cells primarily through the dopamine transporter (DAT), which controls the dynamics of dopamine (DA) neurotransmission by driving the reuptake of extracellular DA into the presynaptic neuronal cell. Additional effects of METH on the storage of DA in synaptic vesicles lead to the dysregulated cytosolic accumulation of DA. Previous studies have shown that after METH disrupts intracellular vesicular stores of DA, the excess DA in the cytosol is rapidly oxidized. This generates an abundance of reactive oxygen species …

The Role Of Glutamate In The Medial Prefrontal Cortex In The Acquistion And Expression Of Conditioned Approach, Rudolf Nisanov

Dissertations, Theses, and Capstone Projects

A series of experiments were conducted to assess the role of glutamatergic stimulation in the dorsal and ventral regions of the medial prefrontal cortex (mPFC) in both the acquisition and expression of reward-related learning using a Pavlovian conditioning paradigm, the conditioned-approach paradigm. Rats with surgically implanted cannulas were exposed to Pavlovian conditioning sessions that occurred on three alternative days (acquisition) or seven consecutive days (expression). These 60-min conditioning sessions consisted of 30 pairings of light (CS) and food pellets (US) presented under a random time schedule. After a two-day break, rats underwent a session with no CS or US and …

Cholinergic Activation Of Corticofugal Circuits In The Adult Mouse Prefrontal Cortex, Allan Gulledge

Dartmouth Scholarship

Acetylcholine (ACh) promotes neocortical output to the thalamus and brainstem by preferentially enhancing the postsynaptic excitability of layer 5 pyramidal tract (PT) neurons relative to neighboring intratelencephalic (IT) neurons. Less is known about how ACh regulates the excitatory synaptic drive of IT and PT neurons. To address this question, spontaneous excitatory postsynaptic potentials (sEPSPs) were recorded in dual recordings of IT and PT neurons in slices of prelimbic cortex from adult female and male mice. ACh (20 µM) enhanced sEPSP amplitudes, frequencies, rise-times, and half-widths preferentially in PT neurons. These effects were blocked by the muscarinic receptor antagonist atropine (1 …

Ribbon Synapses' Role In Synaptic Identification, Lauren Nguyen

Williams Honors College, Honors Research Projects

Understanding the impact of presynaptic and postsynaptic structures on synaptic strength, neurotransmission speed, and morphology is crucial. When cone photoreceptors transmit light-driven signals to cone bipolar cells, various presynaptic structural arrangements can be observed, featuring different numbers of synaptic ribbons. These ribbons facilitate faster initial excitation and sustained transmitter release as vesicles dock at ribbon synapses.

To investigate these structures, I will use the WEBKNOSSOS program to trace dendrites in vertebrate retinal images, determining the number of ribbon synapses and neuron types. This research, building upon the work of Dr. Wan-Qing Yu and Swanstrom, is expected to take about a …

Nalfurafine Promotes Myelination In Vitro And Facilitates Recovery From Cuprizone + Rapamycin-Induced Demyelination In Mice, Ross Van De Wetering, Rabia Bibi, Andy Biggerstaff, Sheein Hong, Bria Pengelly, Thomas E. Prisinzano, Anne C. La Flamme, Bronwyn M. Kivell

Markey Cancer Center Faculty Publications

The kappa opioid receptor has been identified as a promising therapeutic target for promoting remyelination. In the current study, we evaluated the ability of nalfurafine to promote oligodendrocyte progenitor cell (OPC) differentiation and myelination in vitro, and its efficacy in an extended, cuprizone-induced demyelination model. Primary mouse (C57BL/6J) OPC-containing cultures were treated with nalfurafine (0.6–200 nM), clemastine (0.01–100 μM), T3 (30 ng/mL), or vehicle for 5 days. Using immunocytochemistry and confocal microscopy, we found that nalfurafine treatment increased OPC differentiation, oligodendrocyte (OL) morphological complexity, and myelination of nanofibers in vitro. Adult male mice (C57BL/6J) were given a diet con- taining …

Calcium And Proteasomal Regulation Of Er-To-Golgi Protein Transport In Neurons, Samuel A. Galindo

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Regulatory mechanisms of protein trafficking from the endoplasmic reticulum (ER) are critical to understand since neurodegenerative diseases involve defects in this process leading to chronic ER stress and cell death. This study aimed to better understand the calcium regulatory mechanisms of ER-to-Golgi trafficking in hybrid neuroglioblastoma cells (NG108). Specifically, we asked whether proteasomal degradation of transport machinery was involved in the previously demonstrated upregulation of ER-to-Golgi transport evoked by calcium signaling. Based upon previous literature, we believe that the calcium induced increase in transport is due to the activation of the calcium sensitive regulatory protein apoptosis linked gene 2 (ALG-2) …

The Differential Proteomic Response To Ischemic Stroke In Appalachian Subjects Treated With Mechanical Thrombectomy, Christopher J. Mclouth, Benton Maglinger, Jacqueline A. Frank, Kristin J. Hazelwood, Jordan P. Harp, Will Cranford, Shivani Pahwa, David Dornbos Iii, Amanda L. Trout, Ann M. Stowe, Justin F. Fraser, Keith R. Pennypacker

Neurology Faculty Publications

Introduction The Appalachia region of North America is known to have significant health disparities, specifically, worse risk factors and outcomes for stroke. Appalachians are more likely to have comorbidities related to stroke, such as diabetes, obesity, and tobacco use, and are often less likely to have stroke interventions, such as mechanical thrombectomy (MT), for emergent large vessel occlusion (ELVO). As our Comprehensive Stroke Center directly serves stroke subjects from both Appalachian and non-Appalachian areas, inflammatory proteomic biomarkers were identified associated with stroke outcomes specific to subjects residing in Appalachia. Methods There were 81 subjects that met inclusion criteria for this …

Astrocytic Stress Response Is Induced By Exposure To Astrocyte-Binding Antibodies Expressed By Plasmablasts From Pediatric Patients With Acute Transverse Myelitis, Chad Smith, Kiel M. Telesford, Sara G. M. Piccirillo, Yamhilette Licon‑Munoz, Wei Zhang, Key M. Tse, Jacqueline R. Rivas, Chaitanya Joshi, Dilan S. Shah, Angela X. Wu, Ritu Trivedi, Scott Christley, Yu Qian, Lindsay G. Cowell, Richard H. Scheuermann, Ann M. Stowe, Linda Nguyen, Benjamin M. Greenberg, Nancy L. Monson

Neurology Faculty Publications

Background Pediatric acute transverse myelitis (ATM) accounts for 20–30% of children presenting with a first acquired demyelinating syndrome (ADS) and may be the first clinical presentation of a relapsing ADS such as multiple sclerosis (MS). B cells have been strongly implicated in the pathogenesis of adult MS. However, little is known about B cells in pediatric MS, and even less so in pediatric ATM. Our lab previously showed that plasmablasts (PB), the earliest B cell subtype producing antibody, are expanded in adult ATM, and that these PBs produce self‑reactive antibodies that target neurons. The goal of this study was to …

Caenorhabditis Elegans Rapgef Promotes Synaptic Development Through A Small G Protein Signaling Cascade, Reagan Em Lamb

Theses and Dissertations--Neuroscience

Synaptic dysfunction is a major contributor toward the development of many neurological disorders. For proper development, synapses require a series of signaling pathways to guide them, but not all the mechanisms underlying these processes are understood. Here, we used the neuromuscular junction of Caenorhabditis elegans as a model circuitry for examining underlying pathways that mediate proper development of synapses. We hypothesized that the C. elegans RapGEF2 and RapGEF6 orthologue, PXF-1, contributed toward development of cholinergic synapses at the neuromuscular junction. Using behavioral assays and fluorescence microscopy, we found that pxf-1 mutant animals had decreased neuromuscular junction function and decreased synaptic …

Characterizing Age-Associated Cd19+ B Cells After Stroke In Aged Male And Female Mice Reveals Sex-Dependent Functional Recovery, Katie Colson

Theses and Dissertations--Neuroscience

Age-Associated B cells (ABCs) are atypical memory B cells commonly expressing CD11b, CD11c, and T-bet. We hypothesized that aged female mice would have worse functional outcomes after stroke due to higher brain-localized ABCs. We identified 6 ABC subsets expressed in the brain, with higher levels in uninjured animals versus 3 weeks after stroke. Contradictory to my hypothesis, aged uninjured males with higher numbers of Classical ABCs (CD11bhighCXCR5+/CXCR5-) in the brain exhibited better motor function, though with limited differences by injury or sex for other classical ABC subsets. Rare CD11b+CXCR5+ populations from uninjured mice secreted more IFN-γ when exposed to TLR7/9 …

Measuring Spontaneous Neurotransmission Using Genetically Encoded Fluorescent Indicators, Amelia Jane Ralowicz

Dartmouth College Ph.D Dissertations

Synaptic connections throughout the nervous system exhibit two forms of neurotransmitter release caused by synaptic vesicle fusion, evoked and spontaneous release. Despite being discovered 70 years ago, the mechanisms governing spontaneous release have remained elusive. Our understanding of spontaneous release lacks mechanistic details including discrepancies in the sources of synaptic vesicles supporting it, the source(s) of calcium supporting it, and most importantly an unclear relationship (cooperative or antagonistic) with evoked release. These gaps exist due to a lack of experimental methods specific to the study of spontaneous release at individual synapses.

This thesis addresses these gaps in two ways. Firstly, …

Sources And Termination Patterns Of Cholinergic Input To The Ventral Nucleus Of The Lateral Lemniscus, Emily Echols

Williams Honors College, Honors Research Projects

Neurons transmit signals through an electrochemical reaction: synapses on dendrites and the cell body receive neurotransmitters, and their effect on the cell determines the signal the cell will transmit. From dendrites to axon and then to another cell at a synaptic cleft, signals can propagate, enhance each other, or inhibit other transmissions until the message is received by the target area. Understanding the science behind neural signaling and structural function begins at the level of the synapse. The neurotransmitter acetylcholine (ACh) plays a substantial role in modulating neural activity in the auditory system, but for many brainstem nuclei the source …