Medical Neurobiology Commons^™

Frontal White Matter Integrity In Adults With Down Syndrome With And Without Dementia, David K. Powell, Allison Caban-Holt, Greg A. Jicha, William C. Robertson, Roberta Davis, Brian T. Gold, Frederick A. Schmitt, Elizabeth Head

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Adults with Down syndrome (DS) are at high risk for developing Alzheimer's disease after the age of 40 years. To detect white matter (WM) changes in the brain linked to dementia, fractional anisotropy (FA) from diffusion tensor imaging was used. We hypothesized that adults with DS without dementia (DS n = 10), DS with dementia (DSAD n = 10) and age matched non-DS subjects (CTL n = 10) would show differential levels of FA and an association with scores from the Brief Praxis Test and the Severe Impairment Battery. WM integrity differences in DS compared with CTL were found predominantly …

Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Depression is common in Parkinson's disease and is associated with cognitive impairment. Dopaminergic medications are effective in treating the motor symptoms of Parkinson's disease; however, little is known regarding the effects of dopaminergic pharmacotherapy on cognitive function in depressed Parkinson patients. This study examines the neuropsychological effects of dopaminergic pharmacotherapy in Parkinsonian depression. We compared cognitive function in depressed and non-depressed Parkinson patients at two time-points: following overnight withdrawal and after the usual morning regimen of dopaminergic medications. A total of 28 non-demented, right-handed patients with mild to moderate idiopathic Parkinson's disease participated. Ten of these patients were depressed according …

Nanotubes As Mitochondrial Uncouplers, Patrick G. Sullivan

Neuroscience Faculty Patents

A method of uncoupling mitochondria in a subject including administering nanotubes to the subject in a therapeutically effective amount, wherein the nanotubes are self-rectifying is provided. A method of decreasing reactive oxygen species and decreasing detrimental loading of Ca²⁺ into mitochondria is provided, including administering a pharmaceutically effective amount of nanotubes into the subject. A method of reducing weight, treating cancer, reducing the effects of traumatic brain injury, or reducing the effects of ageing, in a subject including administering a pharmaceutically effective amount of nanotubes into the subject is also provided.

The P38Α Mapk Regulates Microglial Responsiveness To Diffuse Traumatic Brain Injury, Adam D. Bachstetter, Rachel K. Rowe, Machi Kaneko, Danielle Goulding, Jonathan Lifshitz, Linda J Van Eldik

Sanders-Brown Center on Aging Faculty Publications

Neuropathology after traumatic brain injury (TBI) is the result of both the immediate impact injury and secondary injury mechanisms. Unresolved post-traumatic glial activation is a secondary injury mechanism that contributes to a chronic state of neuroinflammation in both animal models of TBI and human head injury patients. We recently demonstrated, using in vitro models, that p38α MAPK signaling in microglia is a key event in promoting cytokine production in response to diverse disease-relevant stressors and subsequent inflammatory neuronal dysfunction. From these findings, we hypothesized that the p38α signaling pathway in microglia could be contributing to the secondary neuropathologic sequelae after …

Deficiency In P38Β Mapk Fails To Inhibit Cytokine Production Or Protect Neurons Against Inflammatory Insult In In Vitro And In Vivo Mouse Models, Bin Xing, Adam D. Bachstetter, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

The p38 MAPK pathway plays a key role in regulating the production of proinflammatory cytokines, such as TNFα and IL-1β, in peripheral inflammatory disorders. There are four major isoforms of p38 MAPK (p38α, β, δ, γ), with p38α and p38β the targets of most p38 MAPK inhibitor drugs. Our previous studies demonstrated that the p38α MAPK isoform is an important contributor to stressor-induced proinflammatory cytokine up-regulation and neurotoxicity in the brain. However, the potential role of the p38β MAPK isoform in CNS proinflammatory cytokine overproduction and neurotoxicity is poorly understood. In the current studies, we used primary microglia from wild …

Nanotubes As Mitochondrial Uncouplers, Patrick G. Sullivan

Neuroscience Faculty Patents

A method of uncoupling mitochondria in a subject including administering nanotubes to the subject in a therapeutically effective amount, wherein the nanotubes are self-rectifying is provided. A method of decreasing reactive oxygen species and decreasing detrimental loading of Ca²⁺ into mitochondria is provided, including administering a pharmaceutically effective amount of nanotubes into the subject. A method of reducing weight, treating cancer, reducing the effects of traumatic brain injury, or reducing the effects of ageing, in a subject including administering a pharmaceutically effective amount of nanotubes into the subject is also provided.

Nanotubes As Mitochondrial Uncouplers, Patrick G. Sullivan

Neuroscience Faculty Patents

A method of uncoupling mitochondria in a subject including administering nanotubes to the subject in a therapeutically effective amount, wherein the nanotubes are self-rectifying is provided. A method of decreasing reactive oxygen species and decreasing detrimental loading of Ca²⁺ into mitochondria is provided, including administering a pharmaceutically effective amount of nanotubes into the subject. A method of reducing weight, treating cancer, reducing the effects of traumatic brain injury, or reducing the effects of ageing, in a subject including administering a pharmaceutically effective amount of nanotubes into the subject is also provided.

Effects Of Intranasally Administered Dnsp-11 On The Central Dopamine System Of Normal And Parkinsonian Fischer 344 Rats, James H. Sonne

Theses and Dissertations--Neuroscience

Due to the blood-brain barrier, delivery of many drugs to the brain has required intracranial surgery which is prone to complication. Here we show that Dopamine Neuron Stimulating Peptide 11 (DNSP-11), following non-invasive intranasal administration, protects dopaminergic neurons from a lesion model of Parkinson’s disease in the rat. A significant and dose-dependent increase in an index of dopamine turnover (the ratio of DOPAC to dopamine) was observed in the striatum of normal young adult Fischer 344 rats by whole-tissue neurochemistry compared to vehicle administered controls.

Among animals challenged with a moderate, unilateral 6-hydroxy-dopamine (6-OHDA) lesion of the substantia nigra, those …

Glutamate Dysregulation And Hippocampal Dysfunction In Epileptogenesis, Seth R. Batten

Theses and Dissertations--Medical Sciences

Epileptogenesis is the complex process of the brain developing epileptic acitivity. Due to the role of glutamate and the hippocampus in synaptic plasticity a dysregulation in glutamate neurotransmission and hippocampal dysfunction are implicated in the process of epileptogenesis. However, the exact causal factors that promote epileptogenesis are unknown.

We study presynaptic proteins that regulate glutamate neurotransmission and their role in epileptogenesis. The presynaptic protein, tomosyn, is believed to be a negative regulator of glutamate neurotransmission; however, no one has studied the effects of this protein on glutamate transmission in vivo. Furthermore, evidence suggests that mice lacking tomosyn have a …

Human Calmodulin Methyltransferase: Expression, Activity On Calmodulin, And Hsp90 Dependence, Sophia Magen, Roberta Magnani, Sitvanit Haziza, Eli Hershkovitz, Robert Houtz, Franca Cambi, Ruti Parvari

Horticulture Faculty Publications

Deletion of the first exon of calmodulin-lysine N-methyltransferase (CaM KMT, previously C2orf34) has been reported in two multigene deletion syndromes, but additional studies on the gene have not been reported. Here we show that in the cells from 2p21 deletion patients the loss of CaM KMT expression results in accumulation of hypomethylated calmodulin compared to normal controls, suggesting that CaM KMT is essential for calmodulin methylation and there are no compensatory mechanisms for CaM methylation in humans. We have further studied the expression of this gene at the transcript and protein levels. We have identified 2 additional …

Targeting Astrocytes Ameliorates Neurologic Changes In A Mouse Model Of Alzheimer's Disease, Jennifer L. Furman, Diana M. Sama, John C. Gant, Tina L. Beckett, M. Paul Murphy, Adam D. Bachstetter, Linda J. Van Eldik, Christopher M. Norris

Pharmacology and Nutritional Sciences Faculty Publications

Astrocytes are the most abundant cell type in the brain and play a critical role in maintaining healthy nervous tissue. In Alzheimer's disease (AD) and most other neurodegenerative disorders, many astrocytes convert to a chronically "activated" phenotype characterized by morphologic and biochemical changes that appear to compromise protective properties and/or promote harmful neuroinflammatory processes. Activated astrocytes emerge early in the course of AD and become increasingly prominent as clinical and pathological symptoms progress, but few studies have tested the potential of astrocyte-targeted therapeutics in an intact animal model of AD. Here, we used adeno-associated virus (AAV) vectors containing the astrocyte-specific …

Inhibition Of Soluble Tumor Necrosis Factor Ameliorates Synaptic Alterations And Ca2+ Dysregulation In Aged Rats, Diana M. Sama, Hafiz Mohmmad Abdul, Jennifer L. Furman, Irina A. Artiushin, David E. Szymkowski, Stephen W. Scheff, Christopher M. Norris

Graduate Center for Gerontology Faculty Publications

The role of tumor necrosis factor α (TNF) in neural function has been investigated extensively in several neurodegenerative conditions, but rarely in brain aging, where cognitive and physiologic changes are milder and more variable. Here, we show that protein levels for TNF receptor 1 (TNFR1) are significantly elevated in the hippocampus relative to TNF receptor 2 (TNFR2) in aged (22 months) but not young adult (6 months) Fischer 344 rats. To determine if altered TNF/TNFR1 interactions contribute to key brain aging biomarkers, aged rats received chronic (4-6 week) intracranial infusions of XPro1595: a soluble dominant negative TNF that preferentially inhibits …

Active Site Mutations Change The Cleavage Specificity Of Neprilysin., Travis Sexton, Lisa J. Hitchcook, David W. Rodgers, Luke H. Bradley, Louis B. Hersh

Molecular and Cellular Biochemistry Faculty Publications

Neprilysin (NEP), a member of the M13 subgroup of the zinc-dependent endopeptidase family is a membrane bound peptidase capable of cleaving a variety of physiological peptides. We have generated a series of neprilysin variants containing mutations at either one of two active site residues, Phe⁵⁶³ and Ser⁵⁴⁶. Among the mutants studied in detail we observed changes in their activity towards leucine⁵-enkephalin, insulin B chain, and amyloid β_1-40. For example, NEP^F563I displayed an increase in preference towards cleaving leucine⁵-enkephalin relative to insulin B chain, while mutant NEP^S546E was less discriminating …

Disruptions In The Regulation Of Extracellular Glutamate In The Rat Central Nervous System After Diffuse Brain Injury, Jason Michael Hinzman

Theses and Dissertations--Neuroscience

Glutamate, the predominant excitatory neurotransmitter in the central nervous system, is involved in almost all aspects of neurological function including cognition, motor function, memory, learning, decision making, and neuronal plasticity. For normal neurological function, glutamate signaling must be properly regulated. Disrupted glutamate regulation plays a pivotal role in the acute pathophysiology of traumatic brain injury (TBI), disrupting neuronal signaling, initiating secondary injury cascades, and producing excitotoxicity. Increases in extracellular glutamate have been correlated with unfavorable outcomes in TBI survivors, emphasizing the importance of glutamate regulation.

The aim of this thesis was to examine disruptions in the regulation of extracellular glutamate …

Blast-Induced Brain Injury: Influence Of Shockwave Components, Dexter V. Reneer

Theses and Dissertations--Neuroscience

Blast-induced traumatic brain injury (bTBI) has been described as the defining injury of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF). Previously, most blast injury research has focused on the effects of blast on internal, gas filled organs due to their increased susceptibility. However, due to a change in enemy tactics combined with better armor and front-line medical care, bTBI has become one of the most common injuries due to blast. Though there has been a significant amount of research characterizing the brain injury produced by blast, a sound understanding of the contribution of each component of the shockwave to the …

Prion Characterization Using Cell Based Approaches, Vadim Khaychuk

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Prions are the causative agents of a group of lethal, neurodegenerative conditions that include sheep scrapie, bovine spongiform encephalopathy (BSE), and human Creutzfeldt-Jakob disease (CJD). Prions are derived from the conversion of a normal, primarily alpha-helical, cellular prion protein (PrP^C), to an infectious, beta sheet-rich conformer (PrP^Sc). Many unresolved issues surround the process of PrP conversion, and we know very little about cellular responses to these unique pathogens. Our lack of knowledge relates, in part, to the difficulty of infecting cells in vitro with prions. While expression of PrP^C is an absolute requirement for prion …

Nanotubes As Mitochondrial Uncouplers, Patrick G. Sullivan

Neuroscience Faculty Patents

A method of uncoupling mitochondria in a subject including administering nanotubes to the subject in a therapeutically effective amount, wherein the nanotubes are self-rectifying is provided. A method of decreasing reactive oxygen species and decreasing detrimental loading of Ca²⁺ into mitochondria is provided, including administering a pharmaceutically effective amount of nanotubes into the subject. A method of reducing weight, treating cancer, reducing the effects of traumatic brain injury, or reducing the effects of ageing, in a subject including administering a pharmaceutically effective amount of nanotubes into the subject is also provided.

Nigrostriatal Dopamine-Neuron Function From Neurotrophic-Like Peptide Treatment And Neurotrophic Factor Depletion, Ofelia Meagan Littrell

Theses and Dissertations--Neuroscience

Trophic factors have shown great promise in their potential to treat neurological disease. In particular, glial cell line-derived neurotrophic factor (GDNF) has been identified as a potent neurotrophic factor for midbrain dopamine (DA) neurons in the substantia nigra (SN), which lose function in Parkinson’s disease (PD). GDNF progressed to phase II clinical trials, which did not meet proposed endpoints. The large size and binding characteristics of GDNF have been suspected to contribute to some of the shortcomings of GDNF related to delivery to target brain regions. Smaller peptides derived from GDNF (Dopamine-Neuron Stimulating Peptides – DNSPs) have been recently investigated …

Functional Connectivity For Configural And Featural Face Processing In The Broad Autism Phenotype, Jonathan Darrell Clark

University of Kentucky Doctoral Dissertations

During normal development, face processing involves a gradual shift from a featurally oriented style to a mature configural style by adolescence. This shift may coincide with increased right hemispheric dominance for faces supporting configural processing. Previous studies suggest that individuals diagnosed with ASD continue to process faces using individual parts and features into adulthood. This continued bias may be due to deficits in configural processing abilities. The current study investigated measures of functional connectivity during featural and configural processing of faces in broad autism phenotype sibling (ASD-sibs) children compared to age, sex, and handedness matched normal developing (ND) controls and …

Genome-Wide Association Studies At The Interface Of Alzheimer’S Disease And Epidemiologically Related Disorders, Christopher Ryan Simmons

University of Kentucky Doctoral Dissertations

Genome-wide association studies (GWAS)s provide an unbiased means of exploring the landscape of complex genetic disease. As such, these studies have identified genetic variants that are robustly associated with a multitude of conditions. I hypothesize that these genetic variants serve as excellent tools for evaluation of the genetic interface between epidemiologically related conditions. Herein, I test the association between SNPs associated with either (i) plasma lipids, (ii) rheumatoid arthritis (RA) or (iii) diabetes mellitus (DM) and late-onset Alzheimer’s disease (AD) to identify shared genetic variants. Regarding the most significantly AD-associated variants, I have also attempted to elucidate their molecular function. …

Trichloroethylene Exposure And Traumatic Brain Injury Interact And Produce Dual Injury Based Pathology And Pioglitazone Can Attenuate Deficits Following Traumatic Brain Injury, Andrew David Sauerbeck

University of Kentucky Doctoral Dissertations

The development of Parkinson's disease (PD) in humans has been linked to genetic and environmental factors for many years. However, finding common single insults which can produce pathology in humans has proved difficult. Exposure to trichloroethylene (TCE) or traumatic brain injury (TBI) has been shown to be linked to PD and it has also been proposed that multiple insults may be needed for disease development.

The present studies show that exposure to TCE prior to a TBI can result in pathology similar to early PD and that the interaction of both insults is required for impairment in behavioral function, and …

White Matter Diffusion Alterations In Normal Women At Risk Of Alzheimer's Disease, Charles D. Smith, Himachandra Chebrolu, Anders H. Andersen, David A. Powell, Mark A. Lovell, Shuling Xiong, Brian T. Gold

Neurology Faculty Publications

Increased white matter mean diffusivity and decreased fractional anisotropy (FA) has been observed in subjects diagnosed with mild cognitive impairment (MCI) and Alzheimer's disease (AD). We sought to determine whether similar alterations of white matter occur in normal individuals at risk of AD. Diffusion tensor images were acquired in 42 cognitively normal right-handed women with both a family history of dementia and at least one apolipoprotein E4 allele. These were compared with images from 23 normal women without either AD risk factor. Group analyses were performed using tract-based spatial statistics. Reduced FA was observed in the fronto-occipital and inferior temporal …

Neural Mechanisms Of Sympathetic Activation During Hyperinsulinemia And Obesity-Induced Hypertension, Megan Elyse Bardgett

University of Kentucky Doctoral Dissertations

Obesity afflicts more than 30% of the U.S. population and is a major risk factor for the development of hypertension, type II diabetes, and cardiovascular disease. Studies in humans and animals indicate that obesity is associated with increased sympathetic outflow to the vasculature and kidneys. One mechanism postulated to underlie the increase in sympathetic nerve activity (SNA) in obesity is hyperinsulinemia. Little is known regarding the central circuitry underlying elevated SNA and arterial blood pressure (ABP) during hyperinsulinemia and obesity or if sympathoexcitatory circuits are still responsive to insulin in obesity.

Hyperinsulinemic-euglycemic clamps elevate SNA to the hind limb vasculature …

Local Synaptic Network Interactions In The Dentate Gyrus Of A Cortical Contusion Model Of Posttraumatic Epilepsy, Robert F. Hunt Iii

University of Kentucky Doctoral Dissertations

Posttraumatic epilepsy is a common consequence of brain trauma. However, little is known about how long-term changes in local excitatory and inhibitory synaptic networks contribute to epilepsy after closed-head brain injury. This study adapted a widely used model of experimental brain injury as a mouse model of posttraumatic epilepsy. Behavioral seizure activity and alterations in synaptic circuitry in the dentate gyrus were examined in mice after experimental cortical contusion brain injury. Spontaneous behavioral seizures were observed in 20% of mice after moderate injury and 36-40% of mice weeks after severe injury. In the dentate gyrus, most mice displayed regionally localized …

Characterization And Optimization Of Microelectrode Arrays For Glutamate Measurements In The Rat Hippocampus, Pooja Mahendra Talauliker

University of Kentucky Doctoral Dissertations

An overarching goal of the Gerhardt laboratory is the development of an implantable neural device that allows for long-term glutamate recordings in the hippocampus. Proper L-glutamate regulation is essential for hippocampal function, while glutamate dysregulation is implicated in many neurodegenerative diseases. Direct evidence for subregional glutamate regulation is lacking in previous in vivo studies because of limitations in the spatio-temporal resolution of conventional experimental techniques. We used novel enzyme-coated microelectrode arrays (MEAs) for rapid measurements (2Hz) of extracellular glutamate in urethane-anesthetized rats. Potassium-evoked glutamate release was highest in the cornu ammonis 1 (CA1) subregion and lowest in the cornu ammonis …

Age May Be Hazardous To Outcome Following Traumatic Brain Injury: The Mitochondrial Connection, Lesley Knight Gilmer

University of Kentucky Doctoral Dissertations

Older individuals sustaining traumatic brain injury (TBI) experience a much higher incidence of morbidity and mortality. This age-related exacerbated response to neurological insult has been demonstrated experimentally in aged animals, which can serve as a model to combat this devastating clinical problem. The reasons for this worse initial response are unknown but may be related to age-related changes in mitochondrial respiration.

Evidence is shown that mitochondrial dysfunction occurs early following traumatic brain injury (TBI), persists long after the initial insult, and is severitydependent. Synaptic and extrasynaptic mitochondrial fractions display distinct respiration capacities, stressing the importance to analyze these fractions separately. …

Role Of Cyclophilin D In Secondary Spinal Cord And Brain Injury, Jordan Mills Clark

University of Kentucky Doctoral Dissertations

In the hours and days following acute CNS injury, a secondary wave of events is initiated that exacerbate spinal tissue damage and neuronal cell death. A potential mechanism driving these secondary events is opening of the mitochondrial permeability transition pore (mPTP) and subsequent release of several cell death proteins. Previous studies have shown that inhibition of cyclophilin D(CypD), the key regulating component in mPTP opening, was protective against insults that induce necrotic cell death. We therefore hypothesized that CypD-null mice would show improved functional and pathological outcomes following spinal cord injury (SCI) and traumatic brain injury (TBI). Moderate and severe …

Substrate And Regulation Of Mitochondrial Μ-Calpain, Aashish Joshi

University of Kentucky Doctoral Dissertations

μ -Calpain is localized to the mitochondrial intermembrane space. Apoptosisinducing factor (AIF), which executes caspase-independent cell death, is also localized to the mitochondrial intermembrane space. Following processing at the N-terminus, AIF becomes truncated (tAIF) and is released from mitochondria. The protease responsible for AIF processing has not been established. The same submitochondrial localization of mitochondrial μ-calpain and AIF gives support to the hypothesis that mitochondrial μ-calpain may be responsible for processing AIF. Atractyloside-induced tAIF release in rat liver mitochondria was inhibited by cysteine protease inhibitor MDL28170, but not by calpain inhibitors PD150606 or calpastatin. Moreover, μ-calpain immunoreactivity was difficult to …

Glutamate Regulation In The Hippocampal Trisynaptic Pathway In Aging And Status Epilepticus, Michelle Lee Stephens

University of Kentucky Doctoral Dissertations

A positive correlation exists between increasing age and the incidence of hippocampal-associated dysfunction and disease. Normal L-glutamate neurotransmission is absolutely critical for hippocampal function, while abnormal glutamate neurotransmission has been implicated in many neurodegenerative diseases. Previous studies, overwhelmingly utilizing ex vivo methods, have filled the literature with contradicting reports about hippocampal glutamate regulation during aging. For our studies, enzyme-based ceramic microelectrode arrays (MEA) were used for rapid (2 Hz) measurements of extracellular glutamate in the hippocampal trisynaptic pathway of young (3-6 months), late-middle aged (18 mo.) and aged (24 mo.) urethane-anesthetized Fischer 344 rats. Compared to young animals, glutamate terminals …

The Effect Of Pparγ Activation By Pioglitazone On The Lipopolysaccharide-Induced Pge2 And No Production: Potentialunderlying Alteration Of Signaling Transduction, Bin Xing

University of Kentucky Doctoral Dissertations

Microglia-mediated neuroinflammation plays an important role in the pathogenesis of Parkinson's disease (PD). Uncontrolled microglia activation produces major proinflammatory factors including cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) that may cause dopaminergic neurodegeneration. Peroxisome proliferator-activated receptor γ (PPARγ) agonist pioglitazone has potent antiinflammatory property. We hypothesize pioglitazone protects dopaminergic neuron from lipopolysaccharide (LPS)-induced neurotoxicity by interacting with relevant signal pathways, inhibiting microglial activation and decreasing inflammatory mediators.

First, the neuroprotection of pioglitazone was explored. Second, the signaling transductions such as jun N-terminal kinase (JNK) and the interference with these pathways by pioglitazone were investigated. Third, the effect of …