Medical Sciences Commons^™

The Effects Of Exosomal Derived Tsg-6 On Microglia Activation, Jonathan A. Martinez, Rajashekhar Gangaraju Md

Longitudinal Scholar's Project

Following a traumatic brain injury, microglia become overactive for long periods and display pathologic behavior. We have shown that concentrated conditioned media from adipose tissue-derived mesenchymal stem cells (MSC-CCM) can suppress microglial activation. In this pilot study, we evaluated the efficacy of exosomes containing TNF-stimulated gene 6 (TSG6) derived from MSC-CCM on decreasing microglial activation in vitro via phagocytic activity and pro-inflammatory microglial gene expression.

Intravital Imaging Of Cellular Response Due To Traumatic Brain Injury Using Confocal Microscopy, Enoch G. Kim, Jeffrey Horbatiuk, Carolyn Harris

Medical Student Research Symposium

Introduction: Cellular reaction to traumatic brain injury is complex and involves considerable interactions between cells and reactivity to foreign bodies. Our objective was to assess neurons, microglia, astrocytes, and intracellular Ca²⁺ signaling by creating a novel confocal microscopy technique involving an air immersed lens that does not sacrifice resolution and limits signal attenuation. This study aimed to create a consistent dynamic methodology to observe the cortical cellular response using real-time intravital imaging as trauma is being induced.

Methods: Once surgical plane was achieved, rodent cortices were exposed via craniotomy and blunt insertion with a silicone shunt catheter into the …

Massive Loss Of Proprioceptive Ia Synapses In Rat Spinal Motoneurons After Nerve Crush Injuries In The Postnatal Period, Ariadna Arbat-Plana, Sara Bolívar, Xavier Navarro, Esther Udina, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Peripheral nerve injuries (PNIs) induce the retraction from the ventral horn of the synaptic collaterals of Ia afferents injured in the nerve, effectively removing Ia synapses from α-motoneurons. The loss of Ia input impairs functional recovery and could explain, in part, better recovery after PNIs with better Ia synaptic preservation. Synaptic losses correlate with injury severity, speed, and efficiency of muscle reinnervation and requires ventral microglia activation. It is unknown whether this plasticity is age dependent. In neonates, axotomized motoneurons and sensory neurons undergo apoptosis, but after postnatal day 10 most survive. The goal of this study was to analyze …

The Role Of Microglia In Neuroinflammation Of The Spinal Cord After Peripheral Nerve Injury, Tana S. Pottorf, Travis M. Rotterman, William M. Mccallum, Zoë A. Haley-Johnson, Francisco J. Alvarez

Neuroscience, Cell Biology & Physiology Faculty Publications

Peripheral nerve injuries induce a pronounced immune reaction within the spinal cord, largely governed by microglia activation in both the dorsal and ventral horns. The mechanisms of activation and response of microglia are diverse depending on the location within the spinal cord, type, severity, and proximity of injury, as well as the age and species of the organism. Thanks to recent advancements in neuro-immune research techniques, such as single-cell transcriptomics, novel genetic mouse models, and live imaging, a vast amount of literature has come to light regarding the mechanisms of microglial activation and alluding to the function …

Hdac6 Inhibition Reverses Long-Term Doxorubicin-Induced Cognitive Dysfunction By Restoring Microglia Homeostasis, Blake Mcalpin

Dissertations & Theses (Open Access)

One in 8 women in the US will be diagnosed with breast cancer. Currently, doxorubicin is one of the most effective chemotherapies for breast cancer. Unfortunately, up to 60% of survivors report long-term chemotherapy-induced cognitive dysfunction (CICD) characterized by deficits in working memory, processing speed, and executive functioning. Currently, no interventions for CICD have been approved by the US Food and Drug Administration. I show here that a 14-day treatment with a blood-brain barrier permeable histone deacetylase 6 (HDAC6) inhibitor successfully reverses long-term CICD following a therapeutic doxorubicin dosing schedule in female mice, as assessed by the puzzle box test …

The Anti-Inflammatory Agent Bindarit Attenuates The Impairment Of Neural Development Through Suppression Of Microglial Activation In A Neonatal Hydrocephalus Mouse Model, Eri Iwasawa, Farrah N. Brown, Crystal Shula, Fatima Kahn, Sang Hoon Lee, Temugin Berta, David R. Ladle, Kenneth Campbell, Francesco T. Mangano, June Goto

Neuroscience, Cell Biology & Physiology Faculty Publications

Neonatal hydrocephalus presents with various degrees of neuroinflammation and long-term neurologic deficits in surgically treated patients, provoking a need for additional medical treatment. We previously reported elevated neuroinflammation and severe periventricular white matter damage in the progressive hydrocephalus (prh) mutant which contains a point mutation in the Ccdc39 gene, causing loss of cilia-mediated unidirectional CSF flow. In this study, we identified cortical neuropil maturation defects such as impaired excitatory synapse maturation and loss of homeostatic microglia, and swimming locomotor defects in early postnatal prh mutant mice. Strikingly, systemic application of the anti-inflammatory small molecule bindarit significantly supports healthy …

Characterizing The Heterogeneity Of Adult-Onset Leukoencephalopathy With Axonal Spheroids: A Digital Spatial Profiling Study, Peter Liu

Undergraduate Student Research Internships Conference

Adult-onset leukoencephalopathy with axonal spheroids (ALAS) is a group of hereditary, progressive, neurodegenerative disorders involving primarily the central nervous system white matter (WM). ALAS is characterized by patchy, asymmetrical myelin loss and axonal destruction in the WM, predominantly involving the frontoparietal regions. However, the asymmetrical and heterogenous involvement of different brain regions remains poorly characterized.

In this study, digital spatial profiling was performed to investigate the region-specific expressions of 60 proteins. Conventional immunohistochemistry methods was used validate intrepretation of probes. Using a high-plex and high-throughput method, we provide evidence of regional heterogeneity in ALAS, particularly involving key markers of microglia …

Sequence-Specific Extracellular Micrornas Activate Tlr7, Niming Wu

Theses & Dissertations

Toll-like receptors (TLRs) play an important role in the innate immune system. Emerging evidence shows that TLRs, especially endosomal TLRs, can participate in CNS diseases by increasing the production of proinflammatory cytokines via recognition of microRNAs (miRNAs), however which of the miRNAs are able to activate signaling and whether specific sequence motifs are involved remains incompletely defined. Here we found that numerous miRNAs induced TNF-a production across multiple myeloid cell types, including microglia, and that this effect was abolished in cells deficient of TLR7. In particular, miR-20a-5p and miR-148b-3p preferentially stimulate cytokine secretion compared to miR-20b-5p and miR-148a-3p, respectively, despite …

White Matter Inflammation And Executive Dysfunction: Implications For Alzheimer Disease And Vascular Cognitive Impairment, Alexander Levit

Electronic Thesis and Dissertation Repository

White matter integrity is crucial to healthy executive function, the cognitive domain that enables functional independence. However, in the ageing brain, white matter is highly vulnerable. White matter inflammation increases with age and Alzheimer disease (AD), which disrupts the normal function of white matter. This may contribute to executive dysfunction, but the relationship between white matter inflammation and executive function has not been directly evaluated in ageing nor AD. White matter is also particularly vulnerable to cerebrovascular disease, corresponding with the common presentation of executive dysfunction in vascular cognitive impairment (VCI). Thus, white matter may be an important substrate by …

Glia-To-Neuron Transfer Of Mirnas Via Extracellular Vesicles: A New Mechanism Underlying Inflammation-Induced Synaptic Alterations, Ilaria Prada, Martina Gabrielli, Elena Turola, Alessia Iorio, Giulia D'Arrigo, Roberta Parolisi, Mariacristina De Luca, Marco Pacifici, Mattia Bastoni, Marta Lombardi, Giuseppe Legname, Dan Cojoc, Annalisa Buffo, Roberto Furlan, Francesca Peruzzi, Claudia Verderio

School of Medicine Faculty Publications

Recent evidence indicates synaptic dysfunction as an early mechanism affected in neuroinflammatory diseases, such as multiple sclerosis, which are characterized by chronic microglia activation. However, the mode(s) of action of reactive microglia in causing synaptic defects are not fully understood. In this study, we show that inflammatory microglia produce extracellular vesicles (EVs) which are enriched in a set of miRNAs that regulate the expression of key synaptic proteins. Among them, miR-146a-5p, a microglia-specific miRNA not present in hippocampal neurons, controls the expression of presynaptic synaptotagmin1 (Syt1) and postsynaptic neuroligin1 (Nlg1), an adhesion protein which play a crucial role in dendritic …

Role Of Microglial Amylin Receptors In Mediating Beta Amyloid (Aβ)-Induced Inflammation, Wen Fu, Vlatka Vukojevic, Aarti Patel, Rania Soudy, David Mactavish, David Westaway, Kamaljit Kaur, Valeri Goncharuk, Jack Jhamandas

Pharmacy Faculty Articles and Research

Background: Neuroinflammation in the brain consequent to activation of microglia is viewed as an important component of Alzheimer’s disease (AD) pathology. Amyloid beta (Aβ) protein is known to activate microglia and unleash an inflammatory cascade that eventually results in neuronal dysfunction and death. In this study, we sought to identify the presence of amylin receptors on human fetal and murine microglia and determine whether Aβ activation of the inflammasome complex and subsequent release of cytokines is mediated through these receptors.

Methods: The presence of dimeric components of the amylin receptor (calcitonin receptor and receptor activity modifying protein 3) …

Mild Traumatic Brain Injury With Associated Visual System Dysfunction: Investigating Histopathology, Functional Correlates, And A Novel Therapeutic Immune Modulator, Natalie M. Guley

Theses and Dissertations (ETD)

Background. Traumatic brain injury (TBI) is a significant source of morbidity and mortality worldwide. Injuries associated with moderate to severe TBI can be profound, and have historically overshadowed the significant impact mild TBI (mTBI) can have on the lives of affected individuals. Mild TBI can manifest in a number of different ways, but one of the most significant and often debilitating is its impact on the visual system. In order to further investigate the underlying pathology of mTBI and test potential therapeutics, we developed a mouse model of mTBI induced by blast overpressure. In this model, a 50-60 psi …

Glia And Epilepsy: Excitability And Inflammation, Orrin Devinsky, Annamaria Vezzani, Souhel Najjar, Nihal C. De Lanerolle, Michael A. Rogawski

Michael A. Rogawski

Epilepsy is characterized by recurrent spontaneous seizures due to hyperexcitability and hypersynchrony of brain neurons. Current theories of pathophysiology stress neuronal dysfunction and damage, and aberrant connections as relevant factors. Most antiepileptic drugs target neuronal mechanisms. However, nearly one-third of patients have seizures that are refractory to available medications; a deeper understanding of mechanisms may be required to conceive more effective therapies. Recent studies point to a significant contribution by nonneuronal cells, the glia – especially astrocytes and microglia – in the pathophysiology of epilepsy. This review critically evaluates the role of glia-induced hyperexcitability and inflammation in epilepsy.

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 …

Mitogen Activated Protein Kinase Phosphatase-1 Prevents The Development Of Tactile Sensitivity In A Rodent Model Of Neuropathic Pain, Christian Ndong, Russell P. Landry, Joyce A. Deleo, Edgar A. Romero-Sandoval

Dartmouth Scholarship

Neuropathic pain due to nerve injury is one of the most difficult types of pain to treat. Following peripheral nerve injury, neuronal and glial plastic changes contribute to central sensitization and perpetuation of mechanical hypersensitivity in rodents. The mitogen activated protein kinase (MAPK) family is pivotal in this spinal cord plasticity. MAPK phosphatases (MKPs) limit inflammatory processes by dephosphorylating MAPKs. For example, MKP-1 preferentially dephosphorylates p-p38. Since spinal p-p38 is pivotal for the development of chronic hypersensitivity in rodent models of pain, and p-p38 inhibitors have shown clinical potential in acute and chronic pain patients, we hypothesize that induction of …

Progressive Changes In Microglia And Macrophages In Spinal Cord And Peripheral Nerve In The Transgenic Rat Model Of Amyotrophic Lateral Sclerosis, David J. Graber, William F. Hickey, Brent T. Harris

Dartmouth Scholarship

The role of neuroinflammation in motor neuron death of amyotrophic lateral sclerosis (ALS) is unclear. The human mutant superoxide dismutase-1 (hmSOD1)-expressing murine transgenic model of ALS has provided some insight into changes in microglia activity during disease progression. The purpose of this study was to gain further knowledge by characterizing the immunological changes during disease progression in the spinal cord and peripheral nerve using the more recently developed hmSOD1 rat transgenic model of ALS. Using immunohistochemistry, the extent and intensity of tissue CD11b expression in spinal cord, lumbar nerve roots, and sciatic nerve were evaluated in hmSOD1 rats that were …

Cannabinoid Receptor Type 2 Activation Induces A Microglial Anti-Inflammatory Phenotype And Reduces Migration Via Mkp Induction And Erk Dephosphorylation, Edgar A. Romero-Sandoval, Ryan Horvath, Russell P. Landry, Joyce A. Deleo

Dartmouth Scholarship

Cannabinoid receptor type 2 (CBR2) inhibits microglial reactivity through a molecular mechanism yet to be elucidated. We hypothesized that CBR2 activation induces an anti-inflammatory phenotype in microglia by inhibiting extracellular signal-regulated kinase (ERK) pathway, via mitogen-activated protein kinase-phosphatase (MKP) induction. MKPs regulate mitogen activated protein kinases, but their role in the modulation of microglial phenotype is not fully understood.

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 …

The Cns Role Of Toll-Like Receptor 4 In Innate Neuroimmunity And Painful Neuropathy, Flobert Y. Tanga, Nancy Nutile-Mcmenemy, Joyce A. Deleo

Dartmouth Scholarship

Neuropathic pain remains a prevalent and persistent clinical problem because of our incomplete understanding of its pathogenesis. This study demonstrates for the first time, to our knowledge, a critical role for CNS innate immunity by means of microglial Toll-like receptor 4 (TLR4) in the induction phase of behavioral hypersensitivity in a mouse and rat model of neuropathy. We hypothesized that after L5 nerve transection, CNS neuroimmune activation and subsequent cytokine expression are triggered by the stimulation of microglial membrane-bound TLR4. To test this hypothesis, experiments were undertaken to assess tactile and thermal hypersensitivity in genetically altered (i.e., TLR4 knockout and …

Modified Amino Acid Copolymers Suppress Myelin Basic Protein 85–99-Induced Encephalomyelitis In Humanized Mice Through Different Effects On T Cells, Zsolt Illés, Joel N.H. Stern, Jay Reddy, Hanspeter Waldner, Marcin P. Mycko, Celia F. Brosnan, Stephan Ellmerich, Daniel M. Altmann, Laura Santambrogio, Jack L. Strominger, Vijay K. Kuchroo

Jay Reddy Publications

A humanized mouse bearing the HLA-DR2 (DRA/DRB1*1501) pro- tein associated with multiple sclerosis (MS) and the myelin basic protein (MBP) 85–99-specific HLA-DR2-restricted T cell receptor from an MS patient has been used to examine the effectiveness of modified amino acid copolymers poly(F,Y,A,K)n and poly- (V,W,A,K)n in therapy of MBP 85–99-induced experimental auto-immune encephalomyelitis (EAE) in comparison to Copolymer 1 [Copaxone, poly(Y,E,A,K)n]. The copolymers were designed to optimize binding to HLA-DR2. Vaccination, prevention, and treatment of MBP-induced EAE in the humanized mice with copolymers FYAK and VWAK ameliorated EAE more effectively than Copolymer 1, reduced the number of pathological lesions, and …