18th Annual Symposium of the School of Science, Engineering and Health

Message from the Dean We in the School of Science, Engineering and Health welcome you to this 18th Annual Symposium, and our first as Messiah University. Here you will see our students, faculty and staff showcase innovation, creativity, teamwork and professionalism in our academic departments. Basic and applied research in science and health fields stem from curiosity, acquired skill, and a desire to test and improve processes from foundational principles. The outcomes of scientific research expand intellectual understanding and have tremendous impact on quality of life, environmental health, and human flourishing. We miss having you as guests on our campus but warmly welcome you to enjoy this day virtually. Angela Hare Dean School of Science, Engineering and Health, Messiah Universit

Pathway and biomarker discovery in a posttraumatic stress disorder mouse model

Posttraumatic stress disorder (PTSD), a prevalent psychiatric disorder, is caused by exposure to a traumatic event. Individuals diagnosed for PTSD not only experience significant functional impairments but also have higher rates of physical morbidity and mortality. Despite intense research efforts, the neurobiological pathways affecting fear circuit brain regions in PTSD remain obscure and most of the previous studies were limited to characterization of specific markers in periphery or defined brain regions. In my PhD study, I employed proteomics, metabolomics and transcriptomcis technologies interrogating a foot shock induced PTSD mouse model. In addition, I studied the effects of early intervention of chronic fluoxetine treatment. By in silico analyses, altered cellular pathways associated with PTSD were identified in stress-vulnerable brain regions, including prelimbic cortex (PrL), anterior cingulate cortex (ACC), basolateral amygdala (BLA), central nucleus of amygdala(CeA), nucleus accumbens (NAc) and CA1 of the dorsal hippocampus. With RNA sequencing, I compared the brain transcriptome between shocked and control mice, with and without fluoxetine treatment. Differentially expressed genes were identified and clustered, and I observed increased inflammation in ACC and decreased neurotransmitter signaling in both ACC and CA1. I applied in vivo 15N metabolic labeling combined with mass spectrometry to study alterations at proteome level in the brain. By integrating proteomics and metabolomics profiling analyses, I found decreased Citric Acid Cycle pathway in both NAc and ACC, and dysregulated cytoskeleton assembly and myelination pathways in BLA, CeA and CA1. In addition, chronic fluoxetine treatment 12 hours after foot shock prevented altered inflammatory gene expression in ACC, and Citric Acid Cycle in NAc and ACC, and ameliorated conditioned fear response in shocked mice. These results shed light on the role of immune response and energy metabolism in PTSD pathogenesis. Furthermore, I performed microdialysis in medial prefrontal cortex and hippocampus to measure the changes in extracellular norepinephrine and free corticosterone (CORT) in the shocked mouse and related them to PTSD-like symptoms, including hyperaroual and contextual fear response. I found that increased free CORT was related to diate stress response, whereas norepinephrine level, in a brain region specific manner, predicted arousal and contextual fear response one month after trauma. I also applied metabolomics analysis to investigate molecular changes in prefrontal microdialysates of shocked mice. Citric Acid Cycle, Glyoxylate and Dicarboxylate metabolism and Alanine, Aspartate and Glutamate metabolism pathways were found to be involved in foot shock induced hyperarousal. Taken together, my study provides novel insights into PTSD pathogenesis and suggests potential therapeutic applications targeting dysregulated pathways

Pathway and biomarker discovery in a posttraumatic stress disorder mouse model

Posttraumatic stress disorder (PTSD), a prevalent psychiatric disorder, is caused by exposure to a traumatic event. Individuals diagnosed for PTSD not only experience significant functional impairments but also have higher rates of physical morbidity and mortality. Despite intense research efforts, the neurobiological pathways affecting fear circuit brain regions in PTSD remain obscure and most of the previous studies were limited to characterization of specific markers in periphery or defined brain regions. In my PhD study, I employed proteomics, metabolomics and transcriptomcis technologies interrogating a foot shock induced PTSD mouse model. In addition, I studied the effects of early intervention of chronic fluoxetine treatment. By in silico analyses, altered cellular pathways associated with PTSD were identified in stress-vulnerable brain regions, including prelimbic cortex (PrL), anterior cingulate cortex (ACC), basolateral amygdala (BLA), central nucleus of amygdala(CeA), nucleus accumbens (NAc) and CA1 of the dorsal hippocampus. With RNA sequencing, I compared the brain transcriptome between shocked and control mice, with and without fluoxetine treatment. Differentially expressed genes were identified and clustered, and I observed increased inflammation in ACC and decreased neurotransmitter signaling in both ACC and CA1. I applied in vivo 15N metabolic labeling combined with mass spectrometry to study alterations at proteome level in the brain. By integrating proteomics and metabolomics profiling analyses, I found decreased Citric Acid Cycle pathway in both NAc and ACC, and dysregulated cytoskeleton assembly and myelination pathways in BLA, CeA and CA1. In addition, chronic fluoxetine treatment 12 hours after foot shock prevented altered inflammatory gene expression in ACC, and Citric Acid Cycle in NAc and ACC, and ameliorated conditioned fear response in shocked mice. These results shed light on the role of immune response and energy metabolism in PTSD pathogenesis. Furthermore, I performed microdialysis in medial prefrontal cortex and hippocampus to measure the changes in extracellular norepinephrine and free corticosterone (CORT) in the shocked mouse and related them to PTSD-like symptoms, including hyperaroual and contextual fear response. I found that increased free CORT was related to immediate stress response, whereas norepinephrine level, in a brain region specific manner, predicted arousal and contextual fear response one month after trauma. I also applied metabolomics analysis to investigate molecular changes in prefrontal microdialysates of shocked mice. Citric Acid Cycle, Glyoxylate and Dicarboxylate metabolism and Alanine, Aspartate and Glutamate metabolism pathways were found to be involved in foot shock induced hyperarousal. Taken together, my study provides novel insights into PTSD pathogenesis and suggests potential therapeutic applications targeting dysregulated pathways

Cell-to-Cell Communication in Learning and Memory: From Neuro- and Glio-Transmission to Information Exchange Mediated by Extracellular Vesicles

Most aspects of nervous system development and function rely on the continuous crosstalk between neurons and the variegated universe of non-neuronal cells surrounding them. The most extraordinary property of this cellular community is its ability to undergo adaptive modifications in response to environmental cues originating from inside or outside the body. Such ability, known as neuronal plasticity, allows long-lasting modifications of the strength, composition and efficacy of the connections between neurons, which constitutes the biochemical base for learning and memory. Nerve cells communicate with each other through both wiring (synaptic) and volume transmission of signals. It is by now clear that glial cells, and in particular astrocytes, also play critical roles in both modes by releasing different kinds of molecules (e.g., D-serine secreted by astrocytes). On the other hand, neurons produce factors that can regulate the activity of glial cells, including their ability to release regulatory molecules. In the last fifteen years it has been demonstrated that both neurons and glial cells release extracellular vesicles (EVs) of different kinds, both in physiologic and pathological conditions. Here we discuss the possible involvement of EVs in the events underlying learning and memory, in both physiologic and pathological condition

Low-intensity blast-induced mild traumatic brain injury : linking blast physics to biological outcomes

Blast-induced mild traumatic brain injury (mTBI) is of particular concern among military personnel due to exposure to blast energy during military training and combat. The impact of primary low-intensity blast (LIB) mediated pathophysiology upon later neurobehavioral disorders has been controversial. Our prior considerations of blast physics predicted ultrastructural injuries at nanoscale levels. Here, we provide quantitative data using a LIB injury murine model exposed to open-field detonation of 350 g of high-energy explosive C4. The use of an open-field experimental blast generated a primary blast wave with a peak overpressure of 6.76 pounds per square inch (PSI) (46.6 kPa) at a 3-meter (m) distance from the center of the explosion, with no apparent impact / acceleration in exposed animals. We first characterized neuropathological and behavioral changes. Using transmission electron microscopy (TEM), we further identified multifocal neuronal damages, myelin sheath defects, mitochondrial abnormalities, and synaptic dysregulation after LIB injury. Next, we used quantitative proteomics, bioinformatics analysis, biochemical investigations to seek insights into the molecular mechanisms underlying the ultrastructural pathology. Results illustrated the alterations of mitochondrial, axonal, synaptic proteins in related signaling pathways. These observations uncover unique ultrastructural brain abnormalities, biochemical correlates, and associated behavioral changes due to LIB injury. Insights on the early pathogenesis of LIB-induced brain damages provide a template for further characterization of its chronic effects, identification of potential biomarkers and targets for intervention.Includes bibliographical reference

White matter alterations in chronic traumatic encephalopathy

The diagnostic lesions of neurodegenerative tauopathies, such as chronic traumatic encephalopathy (CTE) and Alzheimer’s disease (AD), are located in the cortex, however, white matter pathology is a contributing factor to neurodegeneration. At all stages of disease, white matter axonal and glial morphological abnormalities are present in CTE. Similarly, white matter changes may emerge before cortical pathology in AD. White matter irregularities bear functional consequences, as they are associated to some of the most common and onerous symptoms of these diseases, like cognitive deficits and depression. Individuals with AD present with both reduced white matter integrity and cognitive symptoms starting early in disease progression. In CTE, which is triggered by repetitive head impacts (RHI), individuals are particularly vulnerable to white matter damage as RHI exposure alone is sufficient to injure white matter tracts and induce depression symptoms. In this dissertation, I investigated the cellular and molecular presentation of white matter glial cells, including astrocytes, oligodendrocytes (OLs), and microglia in CTE and AD as compared to controls. To investigate white matter pathology, I examined glial cells on a cellular level. Neuropathologically-verified CTE samples were compared to RHI-experienced controls, with both groups containing samples with and without depressed mood. CTE with depressed mood had reduced myelin and increased neuroinflammatory peripheral cells compared to non-depressed CTE and contained increased numbers of microglia compared to non-depressed CTE and control samples. Using single-nucleus transcriptomics in neuropathologically-verified CTE samples compared to matched RHI-naïve controls, OL loss, iron aggregates, OL iron trafficking dysregulation, and two distinct astrocyte subpopulations were detected in CTE white matter. AD white matter, compared to the same control samples in the same brain region, was also depleted of OLs by single-nucleus transcriptomics. However, OLs did not demonstrate iron-related transcriptional profile like those in CTE and, in further contrast, displayed increased numbers of microglia and astrocytes. Together, these findings implicate previously uncharacterized white matter glia in the neurodegenerative process of CTE and AD and further elucidate the etiology of neurodegeneration-related symptoms in CTE. These findings may aid in the development of therapeutics targeting glial contributions to the pathologic processes of both CTE and AD

Lithium and brain plasticity - studies on glial cell changes and electroconvulsive treatment-induced amnesia in rats

Depression and bipolar disorder, collectively known as mood disorders, are devastating, common and often chronic illnesses. Imaging studies of patients with mood disorders have demonstrated structural changes in several brain regions implicated in mood regulation. Furthermore, bipolar disorder is associated with white matter abnormalities and post mortem analysis of brain tissue from patients with mood disorders have shown glial cell pathology. Electroconvulsive therapy (ECT) and pharmacological treatment with lithium have been used in the treatment of mood disorders for over 70 respectively 60 years, but the mechanisms behind their therapeutic effects remain elusive. We have previously shown increased neurogenesis and NG2 cell proliferation in a rat model of ECT, electroconvulsive seizures (ECS). NG2 cells can differentiate into mature myelinating oligodendrocytes in the adult brain. Moreover, given the fact they are an abundant proliferative cell type in all areas implicated in mood disorders and with a unique capacity to respond directly to neuronal signalling changes through their specialized contacts with neurons, NG2 cells are highly interesting in the context of mood disorder-associated white and grey matter changes. In paper I we show that chronic lithium treatment unlike its stimulating effect on hippocampal neurogenesis, decreased NG2 cell proliferation in the rat dentate hilus of hippocampus, amygdala and corpus callosum. Decreased proliferation could reflect decreased oligodendrogenesis or possibly cell cycle arrest in favour of differentiation into oligodendrocytes. Thus, in paper II we investigated the effect of lithium on remyelination and oligodendrogenesis in corpus callosum after chemically induced demyelination. We found that lithium treatment during the recovery period after the demyelinating insult decreased remyelination and oligodendrogenesis. In addition, the demyelination-induced inflammation was decreased by lithium. Further studies are needed to investigate if those effects are specific for rats, the dose of lithium used and the brain region investigated. Studies from our laboratory have previously shown a low-grade glial cell activation following ECS. In paper III we show that blood-borne macrophages are recruited to the hippocampal vessel walls after ECS. It can represent the first step in an inflammatory process, but when no further signals are acquired further progression through the astrocytic end-feet layer into the brain parenchyma is halted. ECT’s clinical practice and general acceptance has been limited by concerns about side effects, particularly regarding memory deficits. Certain pharmacological agents administered in association with ECT may protect against amnesia. During recent years, lithium has been shown to reduce memory deficits induced by stroke, stress, head trauma etc. in rodents. In paper IV, we investigated the effect of ECS and lithium treatment on spatial memory and demonstrated robust memory loss for a hippocampus-dependent navigational task learned during the week preceding ECS. This finding was consistent in four independent investigations. However the effect of lithium treatment on ECS-induced amnesia was not as conclusive. In two identically designed studies, lithium counteracted the ECS-induced amnesia, but was neither associated with reduced cell death nor reduced microglia activation Importantly though, an anti-amnestic effect of lithium was not found in two following equally designed studies. Further investigations of ECS-related disturbances are currently ongoing in our research group

Cognition based bTBI mechanistic criteria; a tool for preventive and therapeutic innovations

Blast-induced traumatic brain injury has been associated with neurodegenerative and neuropsychiatric disorders. To date, although damage due to oxidative stress appears to be important, the specific mechanistic causes of such disorders remain elusive. Here, to determine the mechanical variables governing the tissue damage eventually cascading into cognitive deficits, we performed a study on the mechanics of rat brain under blast conditions. To this end, experiments were carried out to analyse and correlate post-injury oxidative stress distribution with cognitive deficits on a live rat exposed to blast. A computational model of the rat head was developed from imaging data and validated against in vivo brain displacement measurements. The blast event was reconstructed in silico to provide mechanistic thresholds that best correlate with cognitive damage at the regional neuronal tissue level, irrespectively of the shape or size of the brain tissue types. This approach was leveraged on a human head model where the prediction of cognitive deficits was shown to correlate with literature findings. The mechanistic insights from this work were finally used to propose a novel helmet design roadmap and potential avenues for therapeutic innovations against blast traumatic brain injury