Molecular and Cellular Neuroscience Commons^™

Stromal Interaction Molecule (Stim) Proteins In Microglia And The Impact On Store-Operated Calcium Entry (Soce) And Spinal Cord Injury Recovery, Norah G. Hill

College of Arts & Sciences Senior Theses

In spinal cord injury (SCI), worsening functional outcomes are largely because of secondary injury processes and prolonged chronic inflammation. A major contributor of secondary injury is overload of intracellular calcium, causing neuronal overexcitation and persistent inflammatory responses. One of the primary mediators of calcium entry into the cell is store-operated calcium entry (SOCE). In SOCE, sensors detecting calcium depletion from the endoplasmic reticulum stores are called STIM proteins (1-2). When calcium is low in the cell, STIM proteins will activate Orai channels to open, allowing for the influx of calcium into the cell. The purpose of this study was to …

Microglial Apoe Across Alzheimer’S Disease-Relevant Pathologies, Georgia Nolt

Theses and Dissertations--Physiology

APOE exists as three common alleles (APOE2, APOE3, APOE4) that encode their corresponding protein isoforms (apoE2, apoE3, apoE4). Despite differing by only one or two single-amino acid substitutions, each APOE allele confers a distinct AD risk profile with APOE4 increasing risk by 28% and APOE2 decreasing risk by 14% compared to the most commonly expressed APOE3 allele. While traditionally considered “neutral,” APOE3 still accounts for ~36% of AD cases while APOE4 contributes ~57%, indicating that the majority of AD cases would not occur in the absence of the APOE3 and APOE4 alleles. Microglia, the resident phagocytic immune cells …

Microglial Expression Of Serotonin Receptors Reveals Parallel Regulation Of 5-Ht2b And Bdnf In The Rat Hippocampus, Andrei Turkin, Maria Sidorova, Ekaterina Kurilova, Natalia Alenina, Oksana Tuchina, Friederike Klempin

School of Graduate Studies Faculty Publications

Growing evidence suggests that psychiatric disorders are characterized by a prolonged inflammatory state, which may influence the efficacy of compounds targeting serotonin. Serotonin is a key signaling molecule in neuroplasticity of the adult hippocampus and involved in antidepressant action. Recent in vitro studies indicate the neurotransmitter may also facilitate the response to inflammation and potentially modulate microglial function towards neuroprotection. Using Tph2−/− rats depleted of brain serotonin, we examined microglial expression of various serotonin receptors (5-HTRs) in vivo in both the hippocampus and prefrontal cortex and assessed mRNA levels of cytokines and brain-derived neurotrophic factor (BDNF). We observed age-dependent and …

Investigating Potential Alzheimer's Disease Therapies Through An Agent-Based Model Of Impaired Microglia Metabolismmodeling Impaired Microglia Metabolism, Cheyenne Ty, Abigail Penland, John Gerving, Martin Mendoza-Ceja, Megan Pratt, Kamila Larripa

Spora: A Journal of Biomathematics

Alzheimer’s disease is the leading cause of dementia globally and is marked by amyloid-β plaque accumulation, decreased brain pH, disrupted metabolism, and increased permeability of the blood-brain barrier. Microglia, the resident immune cells of the central nervous system, are essential for maintaining brain homeostasis and are critically involved in the progression of AD. While microglia can initiate protective immune responses to injury and disease, dysregulated microglial metabolism may contribute to the exacerbation of Alzheimer's pathology. To investigate potential therapeutic strategies, we developed an agent-based model simulating the effects of exercise and metabolic enhancement on dysfunctional microglia. Our findings suggest that …

Neuroinflammation In The Ventral Tegmental Area Of Chronically Stressed Rats, Marie M. Hafez

Honors Projects

Chronic stress has been associated with maladaptive behaviors in both human and animal research models, but the underlying mechanisms are unclear. In this research study, we sought to define whether stress induces neural inflammation in the ventral tegmental area, the brain region primarily responsible for regulating reward consumption, learning, memory, and addictive behaviors through moderating dopamine release in other brain areas. To do this, male Sprague-Dawley rats were subjected to a chronic intermittent stress paradigm that included stressors such as wet bedding, delayed feedings, social isolation, strobe lights, and forced swims. Following the chronic stress intervention, brain sections were collected …

Comprehensive Sumo Proteomic Analyses Identify Hiv Latency-Associated Proteins In Microglia., Fergan Imbert, Dianne Langford

Rowan-Virtua School of Osteopathic Medicine Departmental Research

SUMOylation, the post-translational modification of proteins by small ubiquitin-like modifiers, plays a critical role in regulating various cellular processes, including innate immunity. This modification is essential for modulating immune responses and influencing signaling pathways that govern the activation and function of immune cells. Recent studies suggest that SUMOylation also contributes to the pathophysiology of central nervous system (CNS) viral infections, where it contributes to the host response and viral replication dynamics. Here, we explore the multifaceted role of SUMOylation in innate immune signaling and its implications for viral infections within the CNS. Notably, we present novel proteomic analyses aimed at …

An Agent-Based Model Of Microglia And Neuron Interaction: Implications In Neurodegenerative Disease, Cheyenne Ty, Amanda Case, Emmanuel Mezzulo, Abigail Penland, Kamila Larripa

Spora: A Journal of Biomathematics

Whether immune cells protect or harm the brain is an open question depending on context, and their role is implicated in multiple diseases such as Alzheimer's disease, dementia, and other neurological disorders. Microglia, a specific type of immune cell in the central nervous system, play a key role in homeostasis, and genes associated with an elevated risk of Alzheimer's disease correspond with deficiencies in their behavior. We created an agent-based model that incorporates inflammatory signaling, chemotaxis, and phagocytosis of damaged neurons and allows the exploration of crucial pathways in the maintenance of brain health. We specifically investigated pathways related to …

A Pathologic Study Of Perivascular Ptdp-43 Lin Bodies In Late-Nc, Ryan K. Shahidehpour, Peter T. Nelson, Adam D. Bachstetter

Neurology Faculty Publications

Background TAR DNA-Binding Protein 43 (TDP-43) pathological inclusions are a distinctive feature in dozens of neurodegenerative pathologies, including limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC). Prior investigations identified vascular-associated TDP-43-positive micro-lesions, known as “Lin bodies,” located on or near the brain capillaries of some individuals with LATE-NC. This study aimed to investigate the relationship between the accumulation of Lin bodies and glial cells in LATE-NC and the potential co-localization with ferritin, a protein associated with iron storage. Using multiplexed immunohistochemistry and digital pathology tools, we conducted pathological analyses to investigate the relationship between Lin bodies and glial markers (GFAP for …

Complement Propagates Visual System Pathology After Traumatic Brain Injury, Davis Marchant Borucki

MUSC Theses and Dissertations

Background: Traumatic brain injury is associated with the development of visual system disorders, including deficits in visual acuity. Visual deficits can present with delay and worsen over time, suggesting that ongoing neuroinflammatory changes contribute to their development and progression. Complement activation is strongly associated with the neuroinflammatory response after TBI and has been shown to contribute to neuronal and synaptic loss. However, the contributions of complement activation after TBI to vision loss remains unclear.

Methods: We employed an open skull controlled cortical impact model of traumatic brain injury in adult male mice to study how TBI affects vision. Animals were …

Isolation Of Aged Mouse Primary Microglia As A Model System For Alzheimer’S Disease Research, Michael Landis

Biology Honors Papers

Microglia and their role as the immune cells of the central nervous system are an emerging area of interest within Alzheimer’s research, particularly as they have shown in a benevolent and malevolent cellular context. Models of Alzheimer’s disease are very light in studying microglia, so in this study a model of microglia isolated from aged mice is established in order to study the phagocytic activity and protein expression of microglia in response to Amyloid Beta. The cells were isolated from aged mice and cultured before being used to confirm cellular identity, as well as to measure phagocytic activity. This study …

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 …

Biogenesis And Function Of Microglial Extracellular Vesicles In Neuroinflammation And Parkinson’S Disease, Karl E. Biggs

Dartmouth College Ph.D Dissertations

Microglia are subject to chronic proteinaceous and environmental stress during the progression of prevalent neurodegenerative diseases such as Parkinson’s Disease (PD). Chronic stress can activate the NLR family pyrin domain containing 3 (NLRP3) pattern recognition receptor resulting in the formation of the NLRP3 inflammasome, proinflammatory signaling, and pyroptotic cell death. A distinct subset of extracellular vesicles (EVs) are released from cells upon NLRP3 activation. We studied WT and Nlrp3^-/- primary microglia exposed to bacterial stimulating agents and alpha synuclein preformed fibrils (αsyn PFFs), which model Parkinson’s disease and associated synucleinopathies. We identified the NLRP3-dependent release of the endosome fate …

Cyclophosphamide And Epirubicin Induce Apoptotic Cell Death In Microglia Cells, Rafael De La Hoz-Camacho

Research Symposium

Background. Chemotherapy Related Cognitive Impairment’s (CRCI), diminish patient’s quality life, being breast cancer (BC) patients the most affected. Microglia is described to play a major role in CRCI; hence, the aim of this research was to describe the cytotoxicity of cyclophosphamide (CTX) and Epirubicin (EPI), on microglia (SIM-A9), compared to BC cells (4T1).

Methods. We assessed cell viability (Resazurin) and cell death (AnnV), as well as nuclear damage with γ-H2AX, p53, p16 and cell cycle analysis (PI staining) by flow cytometry (FC). Furthermore, we evaluated ΔΨm (DIOC6), ROS (DCFDA) and NO (DAF-FM) production. Finally, caspase activation (TF2-VAD-FMK) and autophagy (CYTO-ID). …

Inhibition Of Acid Sphingomyelinase Reduces Reactive Astrocyte Secretion Of Mitotoxic Extracellular Vesicles And Improves Alzheimer’S Disease Pathology In The 5xfad Mouse, Simone M. Crivelli, Zainuddin Quadri, Hemendra J. Vekaria, Zhihui Zhu, Priyanka Tripathi, Ahmed Elsherbini, Liping Zhang, Patrick G. Sullivan, Erhard Bieberich

Markey Cancer Center Faculty Publications

In Alzheimer’s disease (AD), reactive astrocytes produce extracellular vesicles (EVs) that affect mitochondria in neurons. Here, we show that Aβ-induced generation of the sphingolipid ceramide by acid sphingomyelinase (A-SMase) triggered proinflammatory cytokine (C1q, TNF-α, IL-1α) release by microglia, which induced the reactive astrocytes phenotype and secretion of EVs enriched with ceramide. These EVs impeded the capacity of neurons to respond to energy demand. Inhibition of A-SMase with Arc39 and Imipramine reduced the secretion of cytokines from microglia, prompting us to test the effect of Imipramine on EV secretion and AD pathology in the 5xFAD mouse model. Brain derived-EVs from 5xFAD …

Complement System In Multiple Sclerosis: Its Role In Disease Course And Potential As A Therapeutic Target, Michael R. Linzey

Dartmouth College Ph.D Dissertations

Multiple sclerosis (MS) is a clinically heterogeneous neurological condition characterized by neuroinflammation and neurodegeneration. Relapsing-remitting MS, defined by inflammatory attacks, is the most common initial form of MS and there are currently 23 FDA-approved treatments for these patients. These therapies work primarily by reducing inflammation in the CNS; they do not work well in progressive disease. Therefore, an unmet medical need exists for effective therapeutic options to treat progressive MS (PMS).

In MS, intrathecal immunoglobulins synthesis (IIgS) correlates with disease progression. My goals for this dissertation were to establish the pathological role of IIgS and identify new potential therapeutic …

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

Dissertations and 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 …

Microglia Polarize In Response To Transactive Response Dna-Binding Protein-43 (Tdp-43) And Display Partial Recovery After Removal Of The Stimulus, Alicen Wilcox

Honors Theses

The proper response to protein signals is necessary for a healthy central nervous system (CNS), and protein dysregulation is a feature of neurodegenerative diseases. Transactive response DNA-binding protein-43 (TDP-43) is an intranuclear protein, but mislocalization is associated with amyotrophic lateral sclerosis (ALS). TDP-43 is released into the extracellular space where it is sensed by microglia, the CNS-resident immune cells. Our data and the literature suggest that microglia respond to TDP-43 dysregulation by increasing CNS inflammation. The goal of this study was to determine the impact of TDP-43 on microglial function and the extent to which microglia recovery. To study the …

Myelin, Cpla2, And Azithromycin: Modulation Of Macrophage Activation In Spinal Cord Injury Inflammation, Timothy J. Kopper

Theses and Dissertations--Physiology

Spinal cord injury (SCI) produces a chronic inflammatory state primarily mediated by macrophages consisting of resident microglia and infiltrating monocytes. These chronically activated SCI macrophages adopt a pro-inflammatory, pathological state that continues to cause additional damage after the initial injury and inhibits recovery. While the roles of macrophages in SCI pathophysiology are well documented, the factors contributing to this maladaptive response are poorly understood. Here, we identify the detrimental effects of myelin debris on macrophage physiology and demonstrate a novel, activation state-dependent role for cytosolic phospholipase-A2 (cPLA₂) in myelin- mediated potentiation of pro-inflammatory macrophage activation. Macrophage- mediated inflammatory …

The Role Of Anti-Inflammatory Cytokine Interleukin-10 (Il-10) In Tauopathies, Lea L. Weston

Biomedical Sciences ETDs

Tauopathies are neurodegenerative diseases, including Alzheimer’s disease, that are associated with pathological accumulation of the microtubule associated protein tau (MAPT, or tau) (Lee et al., 2001). Abnormal hyperphosphorylated tau (pTau) strongly correlate with cognitive impairment (Nelson et al., 2012). Neuroinflammation is also associated with tauopathies (Gerhard et al., 2006b; Edison et al., 2008) and is implicated in driving tau pathology (Yoshiyama et al., 2007, Maphis et al., 2015b). Therefore, it is compelling to understand the role of anti-inflammatory cytokines in limiting neuroinflammation and tau pathology. Interleukin-10 (IL-10) is a well-established anti-inflammatory cytokine with roles in limiting inflammation in the central …

Axonal Regrowth Of Olfactory Sensory Neurons After Chemical Ablation And Removal Of Axonal Debris By Microglia, Rudy Chapman

Electronic Theses and Dissertations

Olfactory sensory neurons (OSNs) are contained within the olfactory epithelium (OE) and are responsible for detecting odorant molecules in the air. The exposure of OSNs to the external environment is necessary for their function, but it also leaves them exposed to potentially harmful elements and thus results in a high turnover rate. Despite the high turnover, the olfactory sense is maintained throughout life through the division of a population of stem cells that produce new OSNs both during normal turnover and after an injury occurs in the OE. When new OSNs are born, they must extend axons from the OE …

Effect Of Reduced Neurogenesis On Microglial Activation, Amelia Smith

Honors Scholars Collaborative Projects

The geriatric population of America has grown exponentially in the past century. Health degradations and expensive medical care are characteristic of this population with many of these costs due to age-related cognitive decline. It is essential to completely understand the mechanisms of normal and abnormal aging in the search for treatments for cognitive decline. A reduction of neurogenesis is a common factor in aging, but this reduction is even more drastic in individuals experiencing cognitive decline. It is unclear what effect reduced neurogenesis has on the extracellular environment, including glial cells. In particular, changes in microglial activation could be related …

Role Of Astrocyte-Derived Extracellular Vesicles In Neuroinflammation Mediated By Drug Abuse, Ke Liao

Theses & Dissertations

Neuronal damage and neuroinflammation is a hallmark feature of HIV-associated neurological disorders (HANDs). Opioids abuse accelerates the incidence and progression of HAND; however, the mechanisms underlying the potentiation of neuropathogenesis by these drugs remain elusive. Extracellular vesicles (EVs) are essential conduits in HIV and drug abuse-mediated synaptodendritic injury and neuroinflammation. Findings from our group have demonstrated that astrocyte-derived EV (ADEV)-miRNA-29b mediates HIV Tat and morphine-induced neuronal injury, thus underscoring the importance of such interactions in NeuroHIV.

Besides, HIV Tat and morphine-mediated synaptodendritic injury via ADEVs, we are also interested in whether ADEVs contributes to neuroinflammation. Microglia are critical players in …

Development And Sensory Experience Dependent Regulation Of Microglia In Barrel Cortex, Joshua C. Brumberg, John Kalambogias, Chia-Chien Chen, Safraz Khan, Titus Son, Carolyn Headlam, Cindy Lin

Publications and Research

The barrel cortex is within the primary somatosensory cortex of the rodent, and processes signals from the vibrissae. Much focus has been devoted to the function of neurons, more recently, the role of glial cells in the processing of sensory input has gained increasing interest. Microglia are the principal immune cells of the nervous system that survey and regulate the cellular constituents of the dynamic nervous system. We investigated the normal and disrupted development of microglia in barrel cortex by chronically depriving sensory signals via whisker trimming for the animals’ first postnatal month. Using immunohistochemistry to label microglia, we performed …

Rejuvenation Of The Epigenetic Landscape Of The Aged Brain Through Manipulation Of Circulating Factors, Edward Koellhoffer

Dissertations and Theses (Open Access)

The aging population of the United States is expanding at an alarming rate. The Center for Disease Control and Prevention estimates that the population of those age 65 years and older will reach over 50 million by 2020 and will double to 100 million by 2060. This will not only put a massive strain on national healthcare resources, but will also increase the number of those who are not able to live and function independently. It is becoming increasingly vital to understand how the brain changes with age and mechanisms to possibly protect and rejuvenate the aged brain to a …

Induction Of Cerebral Hyperexcitability By Peripheral Viral Challenge: Role Of Cxcl10 Chemokine, Tiffany J. Petrisko

Graduate Theses, Dissertations, and Problem Reports (ETD)

Peripheral viral infections are po­tent comorbid factors that exacerbate neuro­degene­ration. Although the under­lying mecha­nisms have not been defined, neuronal hyperexcitability has been established as an underlying feature. Our lab has developed a preclinical model in which a viral mimetic, poly­inosinic-poly­cytidylic acid (PIC) is injected in­tra­peritoneally to induce an anti-viral acute phase response (APR). APR in turn elicits robust neuronal hyperexcitability. The present study was undertaken to characterize molecular mechanisms that mediate the development of hyperexcitability in response to PIC challenge. The analysis of brain tissue after PIC challenge revealed a robust elevation of CXCL10 chemokine, indicating its putative role in …

Mechanisms Of Microglia Mediated Apolipoprotien E Neurotoxicity, Pardeep Singh

Dissertations and Theses

No abstract provided.

Role Of The Fractalkine Receptor In Cns Autoimmune Inflammation: New Approach Utilizing A Mouse Model Expressing The Human Cx3cr1I249/M280 Variant, Sandra M. Cardona, Sangwon V. Kim, Kaira A. Church, Vanessa O. Torres, Ian A. Cleary, Andrew S. Mendiola, Stephen P. Saville, Stephanie S. Watowich, Jan Parker-Thornburg, Alejandro Soto-Ospina, Richard M. Ransohoff, Astrid E. Cardona

Peer Reviewed Articles

Multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS) is the leading cause of non-traumatic neurological disability in young adults. Immune mediated destruction of myelin and oligodendrocytes is considered the primary pathology of MS, but progressive axonal loss is the major cause of neurological disability. In an effort to understand microglia function during CNS inflammation, our laboratory focuses on the fractalkine/CX3CR1 signaling as a regulator of microglia neurotoxicity in various models of neurodegeneration. Fractalkine (FKN) is a transmembrane chemokine expressed in the CNS by neurons and signals through its unique receptor CX3CR1 present in microglia. During …

Mechanisms Regulating Axon Initial Segment Stability, Savannah D. Benusa

Theses and Dissertations

Axon initial segment (AIS) disruption has been described in a number of pathological environments where neuroinflammation is a contributing factor; however, whether this disruption is reversible in unknown. To address the principle of AIS structural recovery, we employed an acute neuroinflammatory model. Acute neuroinflammation induced disruption of AIS structural and functional domains and, importantly, upon resolution of neuroinflammatory conditions, was reversed.

Consistent with other studies, we observed a close interaction of microglia with AISs, and utilized this acute neuroinflammatory model to investigate the relationship between reactive microglia and AIS integrity. Gene expression analysis of microglial transcription profiles identified reactive oxygen …