Medicine and Health Sciences Commons^™

Deep Learning-Based Predictive Classification Of Functional Subpopulations Of Hematopoietic Stem Cells And Multipotent Progenitors., Shen Wang, Jianzhong Han, Jingru Huang, Khayrul Islam, Yuheng Shi, Yuyuan Zhou, Dongwook Kim, Jane Zhou, Zhaorui Lian, Yaling Liu, Jian Huang

Cooper Medical School of Rowan University Faculty Scholarship

BACKGROUND: Hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) play a pivotal role in maintaining lifelong hematopoiesis. The distinction between stem cells and other progenitors, as well as the assessment of their functions, has long been a central focus in stem cell research. In recent years, deep learning has emerged as a powerful tool for cell image analysis and classification/prediction.

METHODS: In this study, we explored the feasibility of employing deep learning techniques to differentiate murine HSCs and MPPs based solely on their morphology, as observed through light microscopy (DIC) images.

RESULTS: After rigorous training and validation using extensive image …

Close Contacts Of Xenograft Recipients: Ethical Considerations Due To Risk Of Xenozoonosis, Daniel J Hurst, Luz Padilla, Daniel Rodger, Tamar Schiff, David K C Cooper

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

With decades of pre-clinical studies culminating in the recent clinical application of xenotransplantation, it would appear timely to provide recommendations for operationalizing oversight of xenotransplantation clinical trials. Ethical issues with clinical xenotransplantation have been described for decades, largely centering on animal welfare, the risks posed to the recipient, and public health risks posed by potential spread of xenozoonosis. Much less attention has been given to considerations relating to potentially elevated risks faced by those who may care for or otherwise have close contact with xenograft recipients. This paper examines the ethical and logistical issues raised by the potential exposure to …

Combined Effects Of Exercise And Immuno-Chemotherapy Treatments On Tumor Growth In Mc38 Colorectal Cancer-Bearing Mice., Manon Gouez, Amélie Rébillard, Amandine Thomas, Sabine Beaumel, Eva-Laure Matera, Etienne Gouraud, Luz Orfila, Brice Martin, Olivia Pérol, Cédric Chaveroux, Erica N. Chirico, Charles Dumontet, Béatrice Fervers, Vincent Pialoux

Cooper Medical School of Rowan University Faculty Scholarship

Acute exercise induces transient modifications in the tumor microenvironment and has been linked to reduced tumor growth along with increased infiltration of immune cells within the tumor in mouse models. In this study, we aimed to evaluate the impact of acute exercise before treatment administration on tumor growth in a mice model of MC38 colorectal cancer receiving an immune checkpoint inhibitor (ICI) and chemotherapy. Six-week-old mice injected with colorectal cancer cells (MC38) were randomized in 4 groups: control (CTRL), immuno-chemotherapy (TRT), exercise (EXE) and combined intervention (TRT/EXE). Both TRT and TRT-EXE received ICI: anti-PD1-1 (1 injection/week) and capecitabine + oxaliplatin …

Fused In Sarcoma Regulates Glutamate Signaling And Oxidative Stress Response, Chiong-Hee Wong, Abu Rahat, Howard C Chang

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Mutations in fused in sarcoma (fust-1) are linked to ALS. However, how these ALS causative mutations alter physiological processes and lead to the onset of ALS remains largely unknown. By obtaining humanized fust-1 ALS mutations via CRISPR-CAS9, we generated a C. elegans ALS model. Homozygous fust-1 ALS mutant and fust-1 deletion animals are viable in C. elegans. This allows us to better characterize the molecular mechanisms of fust-1-dependent responses. We found FUST-1 plays a role in regulating superoxide dismutase, glutamate signaling, and oxidative stress. FUST-1 suppresses SOD-1 and VGLUT/EAT-4 in the nervous system. FUST-1 also regulates synaptic AMPA-type glutamate receptor …

Nucleus Accumbens Core Single Cell Ensembles Bidirectionally Respond To Experienced Versus Observed Aversive Events, Oyku Dinckol, Noah Harris Wenger, Jennifer E Zachry, Munir Gunes Kutlu

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Fear learning is a critical feature of survival skills among mammals. In rodents, fear learning manifests itself through direct experience of the aversive event or social transmission of aversive stimuli such as observing and acting on conspecifics' distress. The neuronal network underlying the social transmission of information largely overlaps with the brain regions that mediate behavioral responses to aversive and rewarding stimuli. In this study, we recorded single cell activity patterns of nucleus accumbens (NAc) core neurons using in vivo optical imaging of calcium transients via miniature scopes. This cutting-edge imaging methodology not only allows us to record activity patterns …

Neutralizing Antibodies Against Ebv Gp42 Show Potent In Vivo Protection And Define Novel Epitopes, Qian Wu, Ling Zhong, Dongmei Wei, Wanlin Zhang, Junping Hong, Yinfeng Kang, Kaiyun Chen, Yang Huang, Qingbing Zheng, Miao Xu, Mu-Sheng Zeng, Yi-Xin Zeng, Ningshao Xia, Qinjian Zhao, Claude Krummenacher, Yixin Chen, Xiao Zhang

Faculty Scholarship for the College of Science & Mathematics

Epstein-Barr virus (EBV) is the first reported human oncogenic virus and infects more than 95% of the human population worldwide. EBV latent infection in B lymphocytes is essential for viral persistence. Glycoprotein gp42 is an indispensable member of the triggering complex for EBV entry into B cells. The C-type lectin domain (CTLD) of gp42 plays a key role in receptor binding and is the major target of neutralizing antibodies. Here, we isolated two rabbit antibodies, 1A7 and 6G7, targeting gp42 CTLD with potent neutralizing activity against B cell infection. Antibody 6G7 efficiently protects humanized mice from lethal EBV challenge and …

Invited Review: Adrenocortical Function In Avian And Non-Avian Reptiles: Insights From Dispersed Adrenocortical Cells., Rocco V. Carsia, Patrick J. Mcilroy, Henry B John-Alder

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Herein we review our work involving dispersed adrenocortical cells from several lizard species: the Eastern Fence Lizard (Sceloporus undulatus), Yarrow's Spiny Lizard (Sceloporus jarrovii), Striped Plateau Lizard (Sceloporus virgatus) and the Yucatán Banded Gecko (Coleonyx elegans). Early work demonstrated changes in steroidogenic function of adrenocortical cells derived from adult S. undulatus associated with seasonal interactions with sex. However, new information suggests that both sexes operate within the same steroidogenic budget over season. The observed sex effect was further explored in orchiectomized and ovariectomized lizards, some supported with exogenous testosterone. Overall, a suppressive effect of testosterone was evident, especially in cells …

Voluntary Wheel Running Promotes Resilience To The Behavioral Effects Of Unpredictable Chronic Mild Stress In Male And Female Mice., Elias Elias, Ariel Y Zhang, Abigail G White, Matthew J Pyle, Melissa T Manners

Faculty Scholarship for the College of Science & Mathematics

Besides significant benefits to physical health, exercise promotes mental health, reduces symptoms of mental illness, and enhances psychological development. Exercise can offset the impact of chronic stress, which is a major precursor to the development of mental disorders. The effects of exercise on chronic stress-induced behaviors are contradictory in preclinical studies, primarily due to the lack of data and sex-specific investigations. We sought to evaluate the effects of exercise on chronic stress-induced behavioral changes in both male and female mice. Mice were subjected to an Unpredictable Chronic Mild Stress (UCMS) paradigm with accessibility to running wheels for 2 h daily. …

Oxygen Insufflation Through The Bronchoscope Channel For Sedation-Induced Hypoxia: Safe And Effective., Wissam Abouzgheib, Henry Miller, Thaddeus Bartter

Cooper Medical School of Rowan University Faculty Scholarship

OBJECTIVES: To evaluate both efficacy and safety parameters for insufflation through the bronchoscope as a method of recovery from sedation-induced hypoxia. To explore parameters applicable to use in human beings using an animal model.

MATERIALS AND METHODS: Two adult pigs were sedated enough to depress respiratory drive. The effects of insufflation at 15 l/min (the upper limits of flow that might be used clinically) were then evaluated. Pressure and volume responses to bronchoscopy during intubation and without an endotracheal tube in place were recorded. Several assays were performed for each scenario, with each animal acting as its own control. Recovery …

Dpc29 Promotes Post-Initiation Mitochondrial Translation In Saccharomyces Cerevisiae, Kyle A. Hubble, Michael F. Henry

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We …

Successful Buprenorphine Transition While Overlapping With A Full Opioid Agonist To Treat Chronic Pain: A Case Report, Kishan V. Patel, Sidharth Sahni, Lanvin F. Taylor

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Buprenorphine is a partial mu opioid agonist that has been increasingly utilized to treat patients with chronic pain and opioid use disorder (OUD). The drug has proven to provide significant chronic pain relief at low doses ranging from 75 to 1800 mcg. The conventional buprenorphine transitional process delays its introduction until patients begin withdrawal. However, this process can pose a barrier to both patients and providers due to some patients' inability to tolerate traditional prerequisite withdrawal. To our knowledge, this is a rare reported case to describe a transitional process utilizing buccal buprenorphine in which a patient with chronic pain …

Epidemiological Study Of Trichosporon Asahii Infections Over The Past 23 Years, Haitao Li, Meihong Guo, Congmin Wang, Yibo Li, Anne Marie Fernandez, Thomas N Ferraro, Rongya Yang, Yong Chen

Faculty Scholarship for the College of Science & Mathematics

Trichosporon is a yeast-like basidiomycete, a conditional pathogenic fungus that is rare in the clinic but often causes fatal infections in immunocompromised individuals. Trichosporon asahii is the most common pathogenic fungus in this genus and the occurrence of infections has dramatically increased in recent years. Here, we report a systematic literature review detailing 140 cases of T. asahii infection reported during the past 23 years. Statistical analysis shows that T. asahii infections were most frequently reported within immunodeficient or immunocompromised patients commonly with blood diseases. Antibiotic use, invasive medical equipment and chemotherapy were the leading risk factors for acquiring infection. …

Cyclin C Regulated Oxidative Stress Responsive Transcriptome In Mus Musculus Embryonic Fibroblasts, David C Stieg, Kai-Ti Chang, Katrina F Cooper, Randy Strich

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The transcriptional changes that occur in response to oxidative stress help direct the decision to maintain cell viability or enter a cell death pathway. Cyclin C-Cdk8 is a conserved kinase that associates with the RNA polymerase II Mediator complex that stimulates or represses transcription depending on the locus. In response to oxidative stress, cyclin C, but not Cdk8, displays partial translocation into the cytoplasm. These findings open the possibility that cyclin C relocalization is a regulatory mechanism governing oxidative stress-induced transcriptional changes. In the present study, the cyclin C-dependent transcriptome was determined and compared to transcriptional changes occurring in oxidatively …

Prefrontal Corticotropin-Releasing Factor (Crf) Neurons Act Locally To Modulate Frontostriatal Cognition And Circuit Function., Sofiya Hupalo, Andrea J Martin, Rebecca K Green, David M Devilbiss, Craig W Berridge

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The PFC and extended frontostriatal circuitry support higher cognitive processes that guide goal-directed behavior. PFC-dependent cognitive dysfunction is a core feature of multiple psychiatric disorders. Unfortunately, a major limiting factor in the development of treatments for PFC cognitive dysfunction is our limited understanding of the neural mechanisms underlying PFC-dependent cognition. We recently demonstrated that activation of corticotropin-releasing factor (CRF) receptors in the caudal dorsomedial PFC (dmPFC) impairs higher cognitive function, as measured in a working memory task. Currently, there remains much unknown about CRF-dependent regulation of cognition, including the source of CRF for cognition-modulating receptors and the output pathways modulated …

Reinterpretation Of The Substrate Specificity Of The Voltage-Sensing Phosphatase During Dimerization., Martin Kruse, Susy C Kohout, Bertil Hille

Cooper Medical School of Rowan University Faculty Scholarship

Voltage-sensing phosphatases (VSPs) cleave both 3- and 5-phosphates from inositol phospholipids in response to membrane depolarization. When low concentrations of Ciona intestinalis VSP are expressed in Xenopus laevis oocytes, the 5-phosphatase reaction can be observed during large membrane depolarizations. When higher concentrations are expressed, the 5-phosphatase activity is observed with smaller depolarizations, and the 3-phosphatase activity is revealed with strong depolarization. Here we ask whether this apparent induction of 3-phosphatase activity is attributable to the dimerization that has been reported when VSP is expressed at higher concentrations. Using a simple kinetic model, we show that these enzymatic phenomena can be …

The Zinc Transporter Zipt-7.1 Regulates Sperm Activation In Nematodes, Yanmei Zhao, Chieh-Hsiang Tan, Amber Krauchunas, Andrea Scharf, Nicholas Dietrich, Kurt Warnhoff, Zhiheng Yuan, Marina Druzhinina, Sam Guoping Gu, Long Miao, Andrew Singson, Ronald E Ellis, Kerry Kornfeld

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Sperm activation is a fascinating example of cell differentiation, in which immotile spermatids undergo a rapid and dramatic transition to become mature, motile sperm. Because the sperm nucleus is transcriptionally silent, this transition does not involve transcriptional changes. Although Caenorhabditis elegans is a leading model for studies of sperm activation, the mechanisms by which signaling pathways induce this transformation remain poorly characterized. Here we show that a conserved transmembrane zinc transporter, ZIPT-7.1, regulates the induction of sperm activation in Caenorhabditis nematodes. The zipt-7.1 mutant hermaphrodites cannot self-fertilize, and males reproduce poorly, because mutant spermatids are defective in responding to activating …

Dimerization Of The Voltage-Sensing Phosphatase Controls Its Voltage-Sensing And Catalytic Activity., Vamseedhar Rayaprolu, Perrine Royal, Karen Stengel, Guillaume Sandoz, Susy C Kohout

Cooper Medical School of Rowan University Faculty Scholarship

Multimerization is a key characteristic of most voltage-sensing proteins. The main exception was thought to be the Ciona intestinalis voltage-sensing phosphatase (Ci-VSP). In this study, we show that multimerization is also critical for Ci-VSP function. Using coimmunoprecipitation and single-molecule pull-down, we find that Ci-VSP stoichiometry is flexible. It exists as both monomers and dimers, with dimers favored at higher concentrations. We show strong dimerization via the voltage-sensing domain (VSD) and weak dimerization via the phosphatase domain. Using voltage-clamp fluorometry, we also find that VSDs cooperate to lower the voltage dependence of activation, thus favoring the activation of Ci-VSP. Finally, using …

Persistent Stress-Induced Neuroplastic Changes In The Locus Coeruleus/Norepinephrine System, Olga Borodovitsyna, Neal Joshi, Daniel Chandler

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Neural plasticity plays a critical role in mediating short- and long-term brain responses to environmental stimuli. A major effector of plasticity throughout many regions of the brain is stress. Activation of the locus coeruleus (LC) is a critical step in mediating the neuroendocrine and behavioral limbs of the stress response. During stressor exposure, activation of the hypothalamic-pituitary-adrenal axis promotes release of corticotropin-releasing factor in LC, where its signaling promotes a number of physiological and cellular changes. While the acute effects of stress on LC physiology have been described, its long-term effects are less clear. This review will describe how stress …

Silver Oxide Coatings With High Silver-Ion Elution Rates And Characterization Of Bactericidal Activity., Sarah S Goderecci, Eric Kaiser, Michael Yanakas, Zachary Norris, Jeffrey Scaturro, Robert Oszust, Clarence D Medina, Fallon Waechter, Min Heon, Robert R Krchnavek, Lei Yu, Samuel E Lofland, Renee M Demarest, Gregory A Caputo, Jeffrey D Hettinger

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

This paper reports the synthesis and characterization of silver oxide films for use as bactericidal coatings. Synthesis parameters, dissolution/elution rate, and bactericidal efficacy are reported. Synthesis conditions were developed to create AgO, Ag₂O, or mixtures of AgO and Ag₂O on surfaces by reactive magnetron sputtering. The coatings demonstrate strong adhesion to many substrate materials and impede the growth of all bacterial strains tested. The coatings are effective in killing Escherichia coli and Staphylococcus aureus, demonstrating a clear zone-of-inhibition against bacteria growing on solid media and the ability to rapidly inhibit bacterial growth in planktonic culture. Additionally, the coatings exhibit very …

Inhibition Of Post-Transcriptional Steps In Ribosome Biogenesis Confers Cytoprotection Against Chemotherapeutic Agents In A P53-Dependent Manner, Russell T Sapio, Anastasiya N Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J Manna, Natalie Minkovsky, Dimitri G Pestov

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The p53-mediated nucleolar stress response associated with inhibition of ribosomal RNA transcription was previously shown to potentiate killing of tumor cells. Here, we asked whether targeting of ribosome biogenesis can be used as the basis for selective p53-dependent cytoprotection of nonmalignant cells. Temporary functional inactivation of the 60S ribosome assembly factor Bop1 in a 3T3 cell model markedly increased cell recovery after exposure to camptothecin or methotrexate. This was due, at least in part, to reversible pausing of the cell cycle preventing S phase associated DNA damage. Similar cytoprotective effects were observed after transient shRNA-mediated silencing of Rps19, but not …

Animal Models Of Rheumatoid Pain: Experimental Systems And Insights., Bradford D Fischer, Adeshina Adeyemo, Michael E O'Leary, Andrea Bottaro

Cooper Medical School of Rowan University Faculty Scholarship

Severe chronic pain is one of the hallmarks and most debilitating manifestations of inflammatory arthritis. It represents a significant problem in the clinical management of patients with common chronic inflammatory joint conditions such as rheumatoid arthritis, psoriatic arthritis and spondyloarthropathies. The functional links between peripheral inflammatory signals and the establishment of the neuroadaptive mechanisms acting in nociceptors and in the central nervous system in the establishment of chronic and neuropathic pain are still poorly understood, representing an area of intense study and translational priority. Several well-established inducible and spontaneous animal models are available to study the onset, progression and chronicization …

Antagonism Of Triazolam Self-Administration In Rhesus Monkeys Responding Under A Progressive-Ratio Schedule: In Vivo Apparent Pa2 Analysis., Bradford D Fischer, Donna M Platt, Sundari K Rallapalli, Ojas A Namjoshi, James M Cook, James K Rowlett

Cooper Medical School of Rowan University Faculty Scholarship

BACKGROUND: Conventional benzodiazepines bind non-selectively to GABAA receptors containing α1, α2, α3, and α5 subunits (α1GABAA, α2GABAA, α3GABAA, and α5GABAA receptors, respectively), and the role of these different GABAA receptor subtypes in the reinforcing effects of benzodiazepines has not been characterized fully. We used a pharmacological antagonist approach with available subtype-selective ligands to evaluate the role of GABAA receptor subtypes in the reinforcing effects of the non-selective conventional benzodiazepine, triazolam.

METHODS: Rhesus monkeys (n=4) were trained under a progressive-ratio schedule of intravenous midazolam delivery and dose-response functions were determined for triazolam, in the absence and presence of flumazenil (non-selective antagonist), …

Nack Is An Integral Component Of The Notch Transcriptional Activation Complex And Is Critical For Development And Tumorigenesis, Kelly L Weaver, Marie-Clotilde Alves-Guerra, Ke Jin, Zhiqiang Wang, Xiaoqing Han, Prathibha Ranganathan, Xiaoxia Zhu, Thiago Dasilva, Wei Liu, Francesca Ratti, Renee M Demarest, Cristos Tzimas, Meghan Rice, Rodrigo Vasquez-Del Carpio, Nadia Dahmane, David J Robbins, Anthony J Capobianco

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The Notch signaling pathway governs many distinct cellular processes by regulating transcriptional programs. The transcriptional response initiated by Notch is highly cell context dependent, indicating that multiple factors influence Notch target gene selection and activity. However, the mechanism by which Notch drives target gene transcription is not well understood. Herein, we identify and characterize a novel Notch-interacting protein, Notch activation complex kinase (NACK), which acts as a Notch transcriptional coactivator. We show that NACK associates with the Notch transcriptional activation complex on DNA, mediates Notch transcriptional activity, and is required for Notch-mediated tumorigenesis. We demonstrate that Notch1 and NACK are …

Role Of Gamma-Aminobutyric Acid Type A (Gabaa) Receptor Subtypes In Acute Benzodiazepine Physical Dependence-Like Effects: Evidence From Squirrel Monkeys Responding Under A Schedule Of Food Presentation., Bradford D Fischer, Laura P Teixeira, Michael L Van Linn, Ojas A Namjoshi, James M Cook, James K Rowlett

Cooper Medical School of Rowan University Faculty Scholarship

RATIONALE: Assays of schedule-controlled responding can be used to characterize the pharmacology of benzodiazepines and other GABAA receptor modulators, and are sensitive to changes in drug effects that are related to physical dependence.

OBJECTIVE: The present study used this approach to investigate the role of GABAA receptor subtypes in mediating dependence-like effects following benzodiazepine administration.

METHODS: Squirrel monkeys (n = 6) were trained on a fixed-ratio schedule of food reinforcement. Initially, the response rate-decreasing effects of chlordiazepoxide (0.1-10 mg/kg; nonselective GABAA receptor agonist), zolpidem (0.032-1.0 mg/kg; α1 subunit-containing GABAA subtype-preferring agonist), and HZ-166 (0.1-10 mg/kg; functionally selective α2 and α3 …

Reinforcing Effects Of Compounds Lacking Intrinsic Efficacy At Α1 Subunit-Containing Gabaa Receptor Subtypes In Midazolam- But Not Cocaine-Experienced Rhesus Monkeys., Nina M Shinday, Eileen K Sawyer, Bradford D Fischer, Donna M Platt, Stephanie C Licata, John R Atack, Gerard R Dawson, David S Reynolds, James K Rowlett

Cooper Medical School of Rowan University Faculty Scholarship

Benzodiazepines are prescribed widely but their utility is limited by unwanted side effects, including abuse potential. The mechanisms underlying the abuse-related effects of benzodiazepines are not well understood, although α1 subunit-containing GABAA receptors have been proposed to have a critical role. Here, we examine the reinforcing effects of several compounds that vary with respect to intrinsic efficacy at α2, α3, and α5 subunit-containing GABAA receptors but lack efficacy at α1 subunit-containing GABAA receptors ('α1-sparing compounds'): MRK-623 (functional selectivity for α2/α3 subunit-containing receptors), TPA023B (functional selectivity for α2/α3/α5 subunit-containing receptors), and TP003 (functional selectivity for α3 subunit-containing receptors). The reinforcing effects …

Notch1 Functions As A Tumor Suppressor In A Model Of K-Ras–Induced Pancreatic Ductal Adenocarcinoma, Linda Hanlon, Jacqueline L Avila, Renée M Demarest, Scott Troutman, Megan Allen, Francesca Ratti, Anil K Rustgi, Ben Z Stanger, Fred Radtke, Volkan Adsay, Fenella Long, Anthony J Capobianco, Joseph L Kissil

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

K-ras is the most commonly mutated oncogene in pancreatic cancer and its activation in murine models is sufficient to recapitulate the spectrum of lesions seen in human pancreatic ductal adenocarcinoma (PDAC). Recent studies suggest that Notch receptor signaling becomes reactivated in a subset of PDACs, leading to the hypothesis that Notch1 functions as an oncogene in this setting. To determine whether Notch1 is required for K-ras-induced tumorigenesis, we used a mouse model in which an oncogenic allele of K-ras is activated and Notch1 is deleted simultaneously in the pancreas. Unexpectedly, the loss of Notch1 in this model resulted in increased …

Prolonged Cyclooxygenase-2 Induction In Neurons And Glia Following Traumatic Brain Injury In The Rat, K I Strauss, M F Barbe, R M Marshall Demarest, R Raghupathi, S Mehta, R K Narayan

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.