Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-30 (of 77 Records) |
Query Trace: O'Callaghan J[original query] |
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Syphilis treatment among people who are pregnant in six U.S. states, 2018-2021
Tannis A , Miele K , Carlson JM , O'Callaghan KP , Woodworth KR , Anderson B , Praag A , Pulliam K , Coppola N , Willabus T , Mbotha D , Abetew D , Currenti S , Longcore ND , Akosa A , Meaney-Delman D , Tong VT , Gilboa SM , Olsen EO . Obstet Gynecol 2024 OBJECTIVE: To describe syphilis treatment status and prenatal care among people with syphilis during pregnancy to identify missed opportunities for preventing congenital syphilis. METHODS: Six jurisdictions that participated in SET-NET (Surveillance for Emerging Threats to Pregnant People and Infants Network) conducted enhanced surveillance among people with syphilis during pregnancy based on case investigations, medical records, and linkage of laboratory data with vital records. Unadjusted risk ratios (RRs) were used to compare demographic and clinical characteristics by syphilis stage (primary, secondary, or early latent vs late latent or unknown) and treatment status during pregnancy (adequate per the Centers for Disease Control and Prevention's "Sexually Transmitted Infections Treatment Guidelines, 2021" vs inadequate or not treated) and by prenatal care (timely: at least 30 days before pregnancy outcome; nontimely: less than 30 days before pregnancy outcome; and no prenatal care). RESULTS: As of September 15, 2023, of 1,476 people with syphilis during pregnancy, 855 (57.9%) were adequately treated and 621 (42.1%) were inadequately treated or not treated. Eighty-two percent of the cohort received timely prenatal care. Although those with nontimely or no prenatal care were more likely to receive inadequate or no treatment (RR 2.50, 95% CI, 2.17-2.88 and RR 2.73, 95% CI, 2.47-3.02, respectively), 32.1% of those with timely prenatal care were inadequately or not treated. Those with reported substance use or a history of homelessness were nearly twice as likely to receive inadequate or no treatment (RR 2.04, 95% CI, 1.82-2.28 and RR 1.83, 95% CI, 1.58-2.13, respectively). CONCLUSION: In this surveillance cohort, people without timely prenatal care had the highest risk for syphilis treatment inadequacy; however, almost a third of people who received timely prenatal care were not adequately treated. These findings underscore gaps in syphilis screening and treatment for pregnant people, especially those experiencing substance use and homelessness, and the need for systems-based interventions, such as treatment outside of traditional prenatal care settings. |
Vital signs: Missed opportunities for preventing congenital syphilis - United States, 2022
McDonald R , O'Callaghan K , Torrone E , Barbee L , Grey J , Jackson D , Woodworth K , Olsen E , Ludovic J , Mayes N , Chen S , Wingard R , Johnson Jones M , Drame F , Bachmann L , Romaguera R , Mena L . MMWR Morb Mortal Wkly Rep 2023 72 (46) 1269-1274 INTRODUCTION: Congenital syphilis cases in the United States increased 755% during 2012-2021. Syphilis during pregnancy can lead to stillbirth, miscarriage, infant death, and maternal and infant morbidity; these outcomes can be prevented through appropriate screening and treatment. METHODS: A cascading framework was used to identify and classify missed opportunities to prevent congenital syphilis among cases reported to CDC in 2022 through the National Notifiable Diseases Surveillance System. Data on testing and treatment during pregnancy and clinical manifestations present in the newborn were used to identify missed opportunities to prevent congenital syphilis. RESULTS: In 2022, a total of 3,761 cases of congenital syphilis in the United States were reported to CDC, including 231 (6%) stillbirths and 51 (1%) infant deaths. Lack of timely testing and adequate treatment during pregnancy contributed to 88% of cases of congenital syphilis. Testing and treatment gaps were present in the majority of cases across all races, ethnicities, and U.S. Census Bureau regions. CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Addressing missed opportunities for prevention, primarily timely testing and appropriate treatment of syphilis during pregnancy, is important for reversing congenital syphilis trends in the United States. Implementing tailored strategies addressing missed opportunities at the local and national levels could substantially reduce congenital syphilis. |
The congenital syphilis prevention cascade: Reimagining a missed prevention opportunities framework for effective intervention
O'Callaghan KP , Johnson Jones ML , Mcdonald R , Jackson DA , Grey JA , Kreisel KM , Torrone E . Sex Transm Dis 2023 51 (1) 8-10 Congenital syphilis (CS) rates have risen in the U.S. since 2013. Prevention of CS requires testing and treatment of pregnant and pregnancy-capable persons at high risk for syphilis. We developed a CS Prevention Cascade to assess how effectively testing and treatment interventions reached pregnant persons with a CS outcome. |
Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis
Cao W , Thorpe PG , O'Callaghan K , Kersh EN . Expert Rev Anti Infect Ther 2023 21 (12) 1339-1354 INTRODUCTION: The reemergence of syphilis, especially congenital syphilis, presents a significant public health threat. Accurate diagnosis of syphilis depends on recognition of a constellation of symptoms, review of medical and sexual history, and multiple laboratory tests. While reliable, current tests for syphilis can be difficult to interpret, which can lead to delays in treatment. AREA COVERED: This review summarizes the major advantages and limitations of available diagnostic laboratory methods for syphilis, provides an update on recent advances in laboratory tools, and highlights the urgent need for coordinated efforts to create new tools to halt the resurgence of syphilis. EXPERT OPINION: In syphilis, the wide variety of short-lived signs and symptoms followed by periods of latency create diagnostics challenges. Currently available laboratory tests, when positive, require additional information to interpret (prior testing, treatment, and sexual history). Point-of-care tests that can rapidly and accurately detect both treponemal and non-treponemal antibodies would be a huge step toward reducing test turnaround time and time to treatment. Incorporating biological insights and technology innovations to advance the development of direct detection assays is urgently needed. A comprehensive coordinated effort is critical to stem the tide of rising syphilis in the United States and globally. |
Intermittent systemic exposure to lipopolysaccharide-induced inflammation disrupts hippocampal long-term potentiation and impairs cognition in aging male mice (preprint)
Engler-Chiurazzi EB , Russel AE , Povroznik JM , McDonald K , Porter K , Wang DS , Billig BK , Felton CC , Hammock J , Schreurs BG , O'Callaghan JD , Zwezdaryk KJ , Simpkins JW . bioRxiv 2022 18 279-291 Age-related cognitive decline, a common component of the brain aging process, is associated with significant impairment in daily functioning and quality of life among geriatric adults. While the complexity of mechanisms underlying cognitive aging are still being elucidated, microbial exposure and the multifactorial inflammatory cascades associated with systemic infections is emerging as a potential driver of neurological senescence. The negative cognitive and neurobiological consequences of a single pathogen-associated inflammatory experience, such as that modeled through treatment with lipopolysaccharide (LPS), are well documented. Yet, the brain aging impacts of repeated, intermittent inflammatory challenges are less well studied. To extend the emerging literature assessing the impact of infection burden on cognitive function among normally aging mice, here, we repeatedly exposed adult mice to intermittent LPS challenges during the aging period. Male 10-month-old C57BL6 mice were systemically administered escalating doses of LPS once every two weeks for 2.5 months. We evaluated cognitive consequences using the non-spatial step-through inhibitory avoidance task and both spatial working and reference memory versions of the Morris water maze. We also probed several potential mechanisms, including cortical and hippocampal cytokine/chemokine gene expression as well as hippocampal neuronal function via extracellular field potential recordings. Though there was limited evidence for an ongoing inflammatory state in cortex and hippocampus, we observed impaired learning and memory and a disruption of hippocampal long-term potentiation. These data suggest that a history of intermittent exposure to LPS-induced inflammation is associated with a subtle but significantly accelerated trajectory of cognitive decline. The broader impact of these findings may have important implications for standard of care involving infections in aging individuals or populations at-risk for dementia. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. |
Epigenetic analysis in a murine genetic model of Gulf War illness
Mozhui K , O'Callaghan JP , Ashbrook DG , Prins P , Zhao W , Lu L , Jones BC . Front Toxicol 2023 5 1162749 Of the nearly 1 million military personnel who participated in the 1990-1991 Gulf War, between 25% and 35% became ill with what now is referred to as Gulf War Illness (GWI) by the Department of Defense. Symptoms varied from gastrointestinal distress to lethargy, memory loss, inability to concentrate, depression, respiratory, and reproductive problems. The symptoms have persisted for 30 years in those afflicted but the basis of the illness remains largely unknown. Nerve agents and other chemical exposures in the war zone have been implicated but the long-term effects of these acute exposures have left few if any identifiable signatures. The major aim of this study is to elucidate the possible genomic basis for the persistence of symptoms, especially of the neurological and behavioral effects. To address this, we performed a whole genome epigenetic analysis of the proposed cause of GWI, viz., exposure to organophosphate neurotoxicants combined with high circulating glucocorticoids in two inbred mouse strains, C57BL/6J and DBA/2J. The animals received corticosterone in their drinking water for 7 days followed by injection of diisopropylfluorophosphate, a nerve agent surrogate. Six weeks after DFP injection, the animals were euthanized and medial prefrontal cortex harvested for genome-wide DNA methylation analysis using high-throughput sequencing. We observed 67 differentially methylated genes, notably among them, Ttll7, Akr1c14, Slc44a4, and Rusc2, all related to different symptoms of GWI. Our results support proof of principle of genetic differences in the chronic effects of GWI-related exposures and may reveal why the disease has persisted in many of the now aging Gulf War veterans. |
Paraquat Toxicogenetics: Strain-Related Reduction of Tyrosine Hydroxylase Staining in Substantia Nigra in Mice.
Torres-Rojas C , Zhao W , Zhuang D , O'Callaghan JP , Lu L , Mulligan MK , Williams RW , Jones BC . Front Toxicol 2021 3 722518 Paraquat (PQ) is a putative risk factor for the development of sporadic Parkinson's disease. To model a possible genetic basis for individual differences in susceptibility to exposure to PQ, we recently examined the effects of paraquat on tyrosine hydroxylase (TH)-containing neurons in the substantia nigra pars compacta (SNc) of six members of the BXD family of mice (n = 2-6 per strain). We injected males with 5 mg/kg paraquat weekly three times. The density of TH+ neurons counted by immunocytochemistry at 200x in eight or more sections through the SNc is reduced in five of the six strains relative to control (N = 4 ± 2 mice per strain). TH+ loss ranged from 0 to 20% with an SEM of 1%. The heritability was estimated using standard ANOVA and jackknife resampling and is 0.37 ± 0.05 in untreated animals and 0.47 ± 0.04 in treated animals. These results demonstrate genetic modulation and GxE variation in susceptibility to PQ exposure and the loss of TH staining in the substantia nigra. |
Substance use among persons with syphilis during pregnancy - Arizona and Georgia, 2018-2021
Carlson JM , Tannis A , Woodworth KR , Reynolds MR , Shinde N , Anderson B , Hobeheidar K , Praag A , Campbell K , Carpentieri C , Willabus T , Burkhardt E , Torrone E , O'Callaghan KP , Miele K , Meaney-Delman D , Gilboa SM , Olsen EO , Tong VT . MMWR Morb Mortal Wkly Rep 2023 72 (3) 63-67 Despite universal prenatal syphilis screening recommendations and availability of effective antibiotic treatment, syphilis prevalence during pregnancy and the incidence of congenital syphilis have continued to increase in the United States (1,2). Concurrent increases in methamphetamine, injection drug, and heroin use have been described in women with syphilis (3). CDC used data on births that occurred during January 1, 2018-December 31, 2021, from two states (Arizona and Georgia) that participate in the Surveillance for Emerging Threats to Pregnant People and Infants Network (SET-NET) to describe the prevalence of substance use among pregnant persons with syphilis by congenital syphilis pregnancy outcome (defined as delivery of a stillborn or live-born infant meeting the surveillance case definition for probable or confirmed congenital syphilis). The prevalence of substance use (e.g., tobacco, alcohol, cannabis, illicit use of opioids, and other illicit, nonprescription substances) in persons with a congenital syphilis pregnancy outcome (48.1%) was nearly double that among those with a noncongenital syphilis pregnancy outcome (24.6%). Persons with a congenital syphilis pregnancy outcome were six times as likely to report illicit use of opioids and four times as likely to report using other illicit, nonprescription substances during pregnancy than were persons with a noncongenital syphilis pregnancy outcome. Approximately one half of persons who used substances during pregnancy and had a congenital syphilis pregnancy outcome had late or no prenatal care. Tailored interventions should address barriers and facilitators to accessing screening and treatment for syphilis among persons who use substances. The need for syphilis screening and treatment should be addressed at any health care encounter during pregnancy, especially among persons who use substances. |
Intermittent systemic exposure to lipopolysaccharide-induced inflammation disrupts hippocampal long-term potentiation and impairs cognition in aging male mice
Engler-Chiurazzi EB , Russell AE , Povroznik JM , McDonald KO , Porter KN , Wang DS , Hammock J , Billig BK , Felton CC , Yilmaz A , Schreurs BG , O'Callaghan JD , Zwezdaryk KJ , Simpkins JW . Brain Behav Immun 2022 108 279-291 Age-related cognitive decline, a common component of the brain aging process, is associated with significant impairment in daily functioning and quality of life among geriatric adults. While the complexity of mechanisms underlying cognitive aging are still being elucidated, microbial exposure and the multifactorial inflammatory cascades associated with systemic infections are emerging as potential drivers of neurological senescence. The negative cognitive and neurobiological consequences of a single pathogen-associated inflammatory experience, such as that modeled through treatment with lipopolysaccharide (LPS), are well documented. Yet, the brain aging impacts of repeated, intermittent inflammatory challenges are less well studied. To extend the emerging literature assessing the impact of infection burden on cognitive function among normally aging mice, here, we repeatedly exposed adult mice to intermittent LPS challenges during the aging period. Male 10-month-old C57BL6 mice were systemically administered escalating doses of LPS once every two weeks for 2.5 months. We evaluated cognitive consequences using the non-spatial step-through inhibitory avoidance task, and both spatial working and reference memory versions of the Morris water maze. We also probed several potential mechanisms, including cortical and hippocampal cytokine/chemokine gene expression, as well as hippocampal neuronal function via extracellular field potential recordings. Though there was limited evidence for an ongoing inflammatory state in cortex and hippocampus, we observed impaired learning and memory and a disruption of hippocampal long-term potentiation. These data suggest that a history of intermittent exposure to LPS-induced inflammation is associated with subtle but significantly impaired cognition among normally aging mice. The broader impact of these findings may have important implications for standard of care involving infections in aging individuals or populations at-risk for dementia. |
A pilot reverse virtual screening study suggests toxic exposures caused long-term epigenetic changes in Gulf War Illness.
Jean-Pierre M , Michalovicz LT , Kelly KA , O'Callaghan JP , Nathanson L , Klimas N , JACraddock T . Comput Struct Biotechnol J 2022 20 6206-6213 Gulf War Illness (GWI) is a chronic illness that affects upward of 32% of deployed Veterans to the 1991 Gulf War (GW). The symptoms are medically unexplained, ranging across cognitive deficits, fatigue, gastrointestinal problems, and musculoskeletal pain. Research indicates that chemical warfare agents play a key role in the onset and progression of GWI. The Khamisiyah ammunition storage that housed chemical warfare agents such as sarin, an acetylcholinesterase (AChE) inhibitor, was demolished during the GW, releasing toxicants into the atmosphere affecting deployed troops. Exposure to other chemical agents such as pyridostigmine bromide, N,N-diethyl-m-toluamide, permethrin and chlorpyrifos, were also prevalent during the war. These additional chemical agents have also been shown to inhibit AChE. AChE inhibition induces an acetylcholine build-up, disrupting signals between nerves and muscles, which in high doses leads to asphyxiation. Little is known about low dose exposure. As bioactive compounds tend to interact with multiple proteins with various physiological effect, we aimed to identify other potential shared targets to understand the extent in which these chemicals could lead to GWI. We followed a reverse screening approach where each chemical is computationally docked to a library of protein targets. The programs PharmMapper and TargetNet were used for this purpose, and further analyses were conducted to mark significant changes in participants with GWI. Previously published work on DNA methylation status in GWI was reanalyzed focusing specifically on the predicted shared targets indicating significant changes in DNA methylation of the associated genes. Our findings thus suggest that exposure to GWI-related agents may converge on similar targets with roles in inflammation, neurotransmitter and lipid metabolism, and detoxification which may have impacts on neurodegenerative-like disease and oxidative stress in Veterans with GWI. |
Genomic Basis for Individual Differences in Susceptibility to the Neurotoxic Effects of Diesel Exhaust.
No , l A , Ashbrook DG , Xu F , Cormier SA , Lu L , O'Callaghan JP , Menon SK , Zhao W , Penn AL , Jones BC . Int J Mol Sci 2022 23 (20) 12461 Air pollution is a known environmental health hazard. A major source of air pollution includes diesel exhaust (DE). Initially, research on DE focused on respiratory morbidities; however, more recently, exposures to DE have been associated with neurological developmental disorders and neurodegeneration. In this study, we investigated the effects of sub-chronic inhalation exposure to DE on neuroinflammatory markers in two inbred mouse strains and both sexes, including whole transcriptome examination of the medial prefrontal cortex. We exposed aged male and female C57BL/6J (B6) and DBA/2J (D2) mice to DE, which was cooled and diluted with HEPA-filtered compressed air for 2 h per day, 5 days a week, for 4 weeks. Control animals were exposed to HEPA-filtered air on the same schedule as DE-exposed animals. The prefrontal cortex was harvested and analyzed for proinflammatory cytokine gene expression (Il1ß, Il6, Tnfa) and transcriptome-wide response by RNA-seq. We observed differential cytokine gene expression between strains and sexes in the DE-exposed vs. control-exposed groups for Il1ß, Tnfa, and Il6. For RNA-seq, we identified 150 differentially expressed genes between air and DE treatment related to natural killer cell-mediated cytotoxicity per Kyoto Encyclopedia of Genes and Genomes pathways. Overall, our data show differential strain-related effects of DE on neuroinflammation and neurotoxicity and demonstrate that B6 are more susceptible than D2 to gene expression changes due to DE exposures than D2. These results are important because B6 mice are often used as the default mouse model for DE studies and strain-related effects of DE neurotoxicity warrant expanded studies. |
Advancing the Role of Neuroimmunity and Genetic Susceptibility in Gulf War Illness.
Sullivan K , O'Callaghan JP . Brain Sci 2022 12 (8) Gulf War Illness (GWI) is a chronic multi-symptom disorder affecting as many as 30% of veterans of the 1991 Gulf War [...]. |
The -adrenergic receptor blocker and anti-inflammatory drug propranolol mitigates brain cytokine expression in a long-term model of Gulf War Illness
Michalovicz LT , Kelly KA , Miller DB , Sullivan K , O'Callaghan JP . Life Sci 2021 285 119962 AIMS: Growing evidence suggests that Gulf War Illness (GWI) is the result of underlying neuroimmune dysfunction. For example, previously we found that several GWI-relevant organophosphate acetylcholinesterase inhibitors produce heightened neuroinflammatory responses following subchronic exposure to stress hormone as a mimic of high physiological stress. The goal of the current study was to evaluate the potential for the β-adrenergic receptor inhibitor and anti-inflammatory drug, propranolol, to treat neuroinflammation in a novel long-term mouse model of GWI. MAIN METHODS: Adult male C57BL/6J mice received a subchronic exposure to corticosterone (CORT) at levels mimicking high physiological stress followed by exposure to the sarin surrogate, diisopropyl fluorophosphate (DFP). These mice were then re-exposed to CORT every other week for a total of five weeks, followed by a systemic immune challenge with lipopolysaccharide (LPS). Animals receiving the propranolol treatment were given a single dose (20 mg/kg, i.p.) either four or 11 days prior to the LPS challenge. The potential anti-neuroinflammatory effects of propranolol were interrogated by analysis of cytokine mRNA expression. KEY FINDINGS: We found that our long-term GWI model produces a primed neuroinflammatory response to subsequent immune challenge that is dependent upon GWI-relevant organophosphate exposure. Propranolol treatment abrogated the elaboration of inflammatory cytokine mRNA expression in the brain instigated in our model, having no treatment effects in non-DFP exposed groups. SIGNIFICANCE: Our results indicate that propranolol may be a promising therapy for GWI with the potential to treat the underlying neuroinflammation associated with the illness. |
Boston biorepository, recruitment and integrative network (BBRAIN): A resource for the Gulf War Illness scientific community.
Keating D , Zundel CG , Abreu M , Krengel M , Aenlle K , Nichols D , Toomey R , Chao LL , Golier J , Abdullah L , Quinn E , Heeren T , Groh JR , Koo BB , Killiany R , Loggia ML , Younger J , Baraniuk J , Janulewicz P , Ajama J , Quay M , Baas PW , Qiang L , Conboy L , Kokkotou E , O'Callaghan JP , Steele L , Klimas N , Sullivan K . Life Sci 2021 284 119903 AIMS: Gulf War Illness (GWI), a chronic debilitating disorder characterized by fatigue, joint pain, cognitive, gastrointestinal, respiratory, and skin problems, is currently diagnosed by self-reported symptoms. The Boston Biorepository, Recruitment, and Integrative Network (BBRAIN) is the collaborative effort of expert Gulf War Illness (GWI) researchers who are creating objective diagnostic and pathobiological markers and recommend common data elements for GWI research. MAIN METHODS: BBRAIN is recruiting 300 GWI cases and 200 GW veteran controls for the prospective study. Key data and biological samples from prior GWI studies are being merged and combined into retrospective datasets. They will be made available for data mining by the BBRAIN network and the GWI research community. Prospective questionnaire data include general health and chronic symptoms, demographics, measures of pain, fatigue, medical conditions, deployment and exposure histories. Available repository biospecimens include blood, plasma, serum, saliva, stool, urine, human induced pluripotent stem cells and cerebrospinal fluid. KEY FINDINGS: To date, multiple datasets have been merged and combined from 15 participating study sites. These data and samples have been collated and an online request form for repository requests as well as recommended common data elements have been created. Data and biospecimen sample requests are reviewed by the BBRAIN steering committee members for approval as they are received. SIGNIFICANCE: The BBRAIN repository network serves as a much needed resource for GWI researchers to utilize for identification and validation of objective diagnostic and pathobiological markers of the illness. |
Modeling Neuroimmune Interactions in Human Subjects and Animal Models to Predict Subtype-Specific Multidrug Treatments for Gulf War Illness.
Michalovicz LT , Kelly KA , O'Callaghan J P . Int J Mol Sci 2021 22 (16) Gulf War Illness (GWI) is a persistent chronic neuroinflammatory illness exacerbated by external stressors and characterized by fatigue, musculoskeletal pain, cognitive, and neurological problems linked to underlying immunological dysfunction for which there is no known treatment. As the immune system and the brain communicate through several signaling pathways, including the hypothalamic-pituitary-adrenal (HPA) axis, it underlies many of the behavioral and physiological responses to stressors via blood-borne mediators, such as cytokines, chemokines, and hormones. Signaling by these molecules is mediated by the semipermeable blood-brain barrier (BBB) made up of a monocellular layer forming an integral part of the neuroimmune axis. BBB permeability can be altered and even diminished by both external factors (e.g., chemical agents) and internal conditions (e.g., acute or chronic stress, or cross-signaling from the hypothalamic-pituitary-gonadal (HPG) axis). Such a complex network of regulatory interactions that possess feed-forward and feedback connections can have multiple response dynamics that may include several stable homeostatic states beyond normal health. Here we compare immune and hormone measures in the blood of human clinical samples and mouse models of Gulf War Illness (GWI) subtyped by exposure to traumatic stress for subtyping this complex illness. We do this via constructing a detailed logic model of HPA-HPG-Immune regulatory behavior that also considers signaling pathways across the BBB to neuronal-glial interactions within the brain. We apply conditional interactions to model the effects of changes in BBB permeability. Several stable states are identified in the system beyond typical health. Following alignment of the human and mouse blood profiles in the context of the model, mouse brain sample measures were used to infer the neuroinflammatory state in human GWI and perform treatment simulations using a genetic algorithm to optimize the Monte Carlo simulations of the putative treatment strategies aimed at returning the ill system back to health. We identify several ideal multi-intervention strategies and potential drug candidates that may be used to treat chronic neuroinflammation in GWI. Copyright © 2021 by the authors. Licensee MDPI, Basel, Switzerland. |
Reactive astrocyte nomenclature, definitions, and future directions.
Escartin C , Galea E , Lakatos A , O'Callaghan JP , Petzold GC , Serrano-Pozo A , Steinhäuser C , Volterra A , Carmignoto G , Agarwal A , Allen NJ , Araque A , Barbeito L , Barzilai A , Bergles DE , Bonvento G , Butt AM , Chen WT , Cohen-Salmon M , Cunningham C , Deneen B , De Strooper B , Díaz-Castro B , Farina C , Freeman M , Gallo V , Goldman JE , Goldman SA , Götz M , Gutiérrez A , Haydon PG , Heiland DH , Hol EM , Holt MG , Iino M , Kastanenka KV , Kettenmann H , Khakh BS , Koizumi S , Lee CJ , Liddelow SA , MacVicar BA , Magistretti P , Messing A , Mishra A , Molofsky AV , Murai KK , Norris CM , Okada S , Oliet SHR , Oliveira JF , Panatier A , Parpura V , Pekna M , Pekny M , Pellerin L , Perea G , Pérez-Nievas BG , Pfrieger FW , Poskanzer KE , Quintana FJ , Ransohoff RM , Riquelme-Perez M , Robel S , Rose CR , Rothstein JD , Rouach N , Rowitch DH , Semyanov A , Sirko S , Sontheimer H , Swanson RA , Vitorica J , Wanner IB , Wood LB , Wu J , Zheng B , Zimmer ER , Zorec R , Sofroniew MV , Verkhratsky A . Nat Neurosci 2021 24 (3) 312-325 Reactive astrocytes are astrocytes undergoing morphological, molecular, and functional remodeling in response to injury, disease, or infection of the CNS. Although this remodeling was first described over a century ago, uncertainties and controversies remain regarding the contribution of reactive astrocytes to CNS diseases, repair, and aging. It is also unclear whether fixed categories of reactive astrocytes exist and, if so, how to identify them. We point out the shortcomings of binary divisions of reactive astrocytes into good-vs-bad, neurotoxic-vs-neuroprotective or A1-vs-A2. We advocate, instead, that research on reactive astrocytes include assessment of multiple molecular and functional parameters-preferably in vivo-plus multivariate statistics and determination of impact on pathological hallmarks in relevant models. These guidelines may spur the discovery of astrocyte-based biomarkers as well as astrocyte-targeting therapies that abrogate detrimental actions of reactive astrocytes, potentiate their neuro- and glioprotective actions, and restore or augment their homeostatic, modulatory, and defensive functions. |
A role for neuroimmune signaling in a rat model of Gulf War Illness-related pain
Lacagnina MJ , Li J , Lorca S , Rice KC , Sullivan K , O'Callaghan JP , Grace PM . Brain Behav Immun 2020 91 418-428 More than a quarter of veterans of the 1990-1991 Persian Gulf War suffer from Gulf War Illness (GWI), a chronic, multi-symptom illness that commonly includes musculoskeletal pain. Exposure to a range of toxic chemicals, including sarin nerve agent, are a suspected root cause of GWI. Moreover, such chemical exposures induce a neuroinflammatory response in rodents, which has been linked to several GWI symptoms in rodents and veterans with GWI. To date, a neuroinflammatory basis for pain associated with GWI has not been investigated. Here, we evaluated development of nociceptive hypersensitivity in a model of GWI. Male Sprague Dawley rats were treated with corticosterone in the drinking water for 7 days, to mimic high physiological stress, followed by a single injection of the sarin nerve agent surrogate, diisopropyl fluorophosphate. These exposures alone were insufficient to induce allodynia. However, an additional sub-threshold challenge (a single intramuscular injection of pH 4 saline) induced long-lasting, bilateral allodynia. Such allodynia was associated with elevation of markers for activated microglia/macrophages (CD11b) and astrocytes/satellite glia (GFAP) in the lumbar dorsal spinal cord and dorsal root ganglia (DRG). Additionally, Toll-like receptor 4 (TLR4) mRNA was elevated in the lumbar dorsal spinal cord, while IL-1β and IL-6 were elevated in the lumbar dorsal spinal cord, DRG, and gastrocnemius muscle. Demonstrating a casual role for such neuroinflammatory signaling, allodynia was reversed by treatment with either minocycline, the TLR4 inhibitor (+)-naltrexone, or IL-10 plasmid DNA. Together, these results point to a role for neuroinflammation in male rats in the model of musculoskeletal pain related to GWI. Therapies that alleviate persistent immune dysregulation may be a strategy to treat pain and other symptoms of GWI. |
Exploring the Role of Chemokine Receptor 6 ( Ccr6 ) in the BXD Mouse Model of Gulf War Illness.
Gao J , Xu F , Starlard-Davenport A , Miller DB , O’Callaghan JP , Jones BC , Lu L . Front Neurosci 2020 14 818 Gulf War illness (GWI) is a chronic and multi-symptomatic disorder with persistent neuroimmune symptomatology. Chemokine receptor 6 (CCR6) has been shown to be involved in several inflammation disorders in humans. However, the causative relationship between CCR6 and neuroinflammation in GWI has not yet been investigated. By using RNA-seq data of prefrontal cortex (PFC) from 31 C57BL/6J X DBA/2J (BXD) recombinant inbred (RI) mouse strains and their parental strains under three chemical treatment groups – saline control (CTL), diisopropylfluorophosphate (DFP), and corticosterone combined with diisopropylfluorophosphate (CORT+DFP), we identified Ccr6 as a candidate gene underlying individual differences in susceptibility to GWI. The Ccr6 gene is cis-regulated and its expression is significantly correlated with CORT+DFP treatment. Its mean transcript abundance in PFC of BXD mice decreased 1.6-fold (p < 0.0001) in the CORT+DFP group. The response of Ccr6 to CORT+DFP is also significantly different (p < 0.0001) between the parental strains, suggesting Ccr6 is affected by both host genetic background and chemical treatments. Pearson product-moment correlation analysis revealed 1473 Ccr6-correlated genes (p < 0.05). Enrichment of these genes was seen in the immune, inflammation, cytokine, and neurological related categories. In addition, we also found five central nervous system-related phenotypes and fecal corticosterone concentration have significant correlation (p < 0.05) with expression of Ccr6 in the PFC. We further established a protein-protein interaction subnetwork for the Ccr6-correlated genes, which provides an insight on the interaction of G protein-coupled receptors, kallikrein-kinin system and neuroactive ligand-receptors. This analysis likely defines the heterogeneity and complexity of GWI. Therefore, our results suggest that Ccr6 is one of promising GWI biomarkers. |
Alterations in high-order diffusion imaging in veterans with Gulf War Illness is associated with chemical weapons exposure and mild traumatic brain injury
Cheng CH , Koo BB , Calderazzo S , Quinn E , Aenlle K , Steele L , Klimas N , Krengel M , Janulewicz P , Toomey R , Michalovicz L , Kelly KA , Heeren T , Little D , O'Callaghan J , Sullivan K . Brain Behav Immun 2020 89 281-290 The complex etiology behind Gulf War Illness (GWI) has been attributed to the combined exposure to neurotoxicant chemicals, brain injuries, and some combat experiences. Chronic GWI symptoms have been shown to be associated with intensified neuroinflammatory responses in animal and human studies. To investigate the neuroinflammatory responses and potential causes in Gulf War (GW) veterans, we focused on the effects of chemical/biological weapons (CBW) exposure and mild traumatic brain injury (mTBI) during the war. We applied a novel MRI diffusion processing method, Neurite density imaging (NDI), on high-order diffusion imaging to estimate microstructural alterations of brain imaging in Gulf War veterans with and without GWI, and collected plasma proinflammatory cytokine samples as well as self-reported health symptom scores. Our study identified microstructural changes specific to GWI in the frontal and limbic regions due to CBW and mTBI, and further showed distinctive microstructural patterns such that widespread changes were associated with CBW and more focal changes on diffusion imaging were observed in GW veterans with an mTBI during the war. In addition, microstructural alterations on brain imaging correlated with upregulated blood proinflammatory cytokine markers TNFRI and TNFRII and with worse outcomes on self-reported symptom measures for fatigue and sleep functioning. Taken together, these results suggest TNF signaling mediated inflammation affects frontal and limbic regions of the brain, which may contribute to the fatigue and sleep symptoms of the disease and suggest a strong neuroinflammatory component to GWI. These results also suggest exposures to chemical weapons and mTBI during the war are associated with different patterns of peripheral and central inflammation and highlight the brain regions vulnerable to further subtle microscale morphological changes and chronic signaling to nearby glia. |
Genome-wide Transcriptome Architecture in a Mouse Model of Gulf War Illness.
Xu F , Ashbrook DG , Gao J , Starlard-Davenport A , Zhao W , Miller DB , O'Callaghan JP , Williams RW , Jones BC , Lu L . Brain Behav Immun 2020 89 209-223 Gulf War Illness (GWI) is thought to be a chronic neuroimmune disorder caused by in-theater exposure during the 1990-1991 Gulf War. There is a consensus that the illness is caused by exposure to insecticides and nerve agent toxicants. However, the heterogeneity in both development of disease and clinical outcomes strongly suggests a genetic contribution. Here, we modeled GWI in 30 BXD recombinant inbred strains with a combined treatment of corticosterone (CORT) and diisopropyl fluorophosphate (DFP). We quantified transcriptomes from 409 prefrontal cortex samples. Compared to the untreated and DFP treated controls. The combined treatment significantly activated pathways such as cytokine-cytokine receptor interaction and TNF signaling pathway. Protein-protein interaction analysis defined 6 subnetworks for CORT+DFP, with the key regulators being Cxcl1, Il6, Ccnb1, Tnf, Agt, and Itgam. We also identified 21 differentially expressed genes having significant QTLs related to CORT+DFP, but without evidence for untreated and DFP treated controls, suggesting regions of the genome specifically involved in the response to CORT+DFP. We identified Adamts9 as a potential contributor to response to CORT+DFP and found links to symptoms of GWI. Furthermore, we observed a significant effect of CORT+DFP treatment on the relative proportion of myelinating oligodendrocytes, with a QTL on Chr5. We highlight three candidates, Magi2, Sema3c, and Gnai1, based on their high expression in the brain and oligodendrocyte. In summary, our results show significant genetic effects of the CORT+DFP treatment, which mirrors gene and protein expression changes seen in GWI sufferers, providing insight into the disease and a testbed for future interventions. |
Systems genetics and systems biology analysis of paraquat neurotoxicity in BXD recombinant inbred mice.
Torres-Rojas C , Zhuang D , Jimenez-Carrion P , Silva I , O'Callaghan JP , Lu L , Zhao W , Mulligan MK , Williams RW , Jones BC . Toxicol Sci 2020 176 (1) 137-146 Paraquat (PQ) is an herbicide used in many countries, including the USA. It is also implicated as a risk factor for sporadic Parkinson's disease (sPD), especially in those living in agricultural areas and drinking well water. Studies linking PQ to sPD are not consistent however and there appears to be inter-individual differential susceptibility. One likely reason is genetically based differential susceptibility to paraquat neurotoxicity in sub-populations. To address this issue, we tested the effects of paraquat in a genetic reference population of mice (the BXD recombinant inbred strain family). In our earlier work, we showed that in genetically susceptible mice, paraquat increases iron in the ventral midbrain, the area containing the substantia nigra. Our hypothesis is that genetic variability contributes to diverse PQ-related susceptibility and iron concentration. To test this hypothesis, we treated male mice from 28-39 BXD strains plus the parental strains with one of 3 doses of paraquat, 1, 5 and 10 mg/kg three times on a weekly basis. At the end of the treatment period, we analyzed the ventral midbrain for concentrations of iron, copper, and zinc, also we measured the concentration of paraquat in cerebellum, and proinflammatory cytokines in serum and cerebellum. The effect on paraquat treated mice with 5 mg/kg and principal component analysis of iron showed suggestive QTL on chromosome 5. Overall, our results suggest that gene Prkag2 and related networks may serve as potential targets against paraquat toxicity and demonstrate the utility of genetically diverse mouse models for the study of complex human toxicity. |
Acetylcholinesterase inhibitor exposures as an initiating factor in the development of Gulf War Illness, a chronic neuroimmune disorder in deployed veterans
Michalovicz LT , Kelly KA , Sullivan K , O'Callaghan JP . Neuropharmacology 2020 171 108073 Gulf War Illness (GWI) is a chronic multi-symptom disorder, characterized by symptoms such as fatigue, pain, cognitive and memory impairment, respiratory, skin and gastrointestinal problems, that is experienced by approximately one-third of 1991 Gulf War veterans. Over the nearly three decades since the end of the war, investigators have worked to elucidate the initiating factors and underlying causes of GWI. A significant portion of this research has indicated a strong correlation between GWI and exposure to a number of different acetycholinesterase inhibitors (AChEIs) in theater, such as sarin and cyclosarin nerve agents, chlorpyrifos and dichlorvos pesticides, and the anti-nerve agent prophylactic pyridostigmine bromide. Through studying these exposures and their relationship to the symptoms presented by ill veterans, it has become increasingly apparent that GWI is the likely result of an underlying neuroimmune disorder. While evidence indicates that AChEIs are a key exposure in the development of GWI, particularly organophosphate AChEIs, the mechanism(s) by which these chemicals instigate illness appears to be related to "off-target", non-cholinergic effects. In this review, we will discuss the role of AChEI exposure in the development and persistence of GWI; in particular, how these chemicals, combined with other exposures, have led to a chronic neuroimmune disorder. |
Modeling the Genetic Basis of Individual Differences in Susceptibility to Gulf War Illness.
Jones BC , Miller DB , Lu L , Zhao W , Ashbrook DG , Xu F , Mulligan MK , Williams RW , Zhuang D , Torres-Rojas C , O'Callaghan JP . Brain Sci 2020 10 (3) Between 25% and 30% of the nearly one million military personnel who participated in the 1991 Persian Gulf War became ill with chronic symptoms ranging from gastrointestinal to nervous system dysfunction. This disorder is now referred to as Gulf War Illness (GWI) and the underlying pathophysiology has been linked to exposure-based neuroinflammation caused by organophosphorous (OP) compounds coupled with high circulating glucocorticoids. In a mouse model of GWI we developed, corticosterone was shown to act synergistically with an OP (diisopropylflurophosphate) to dramatically increase proinflammatory cytokine gene expression in the brain. Because not all Gulf War participants became sick, the question arises as to whether differential genetic constitution might underlie individual differences in susceptibility. To address this question of genetic liability, we tested the impact of OP and glucocorticoid exposure in a genetic reference population of 30 inbred mouse strains. We also studied both sexes. The results showed wide differences among strains and overall that females were less sensitive to the combined treatment than males. Furthermore, we identified one OP-glucocorticoid locus and nominated a candidate gene-Spon1-that may underlie the marked differences in response. |
Microglial activation and responses to vasculature that result from an acute LPS exposure
Bowyer JF , Sarkar S , Burks SM , Hess JN , Tolani S , O'Callaghan JP , Hanig JP . Neurotoxicology 2020 77 181-192 Bacterial cell wall endotoxins, i.e. lipopolysaccharides (LPS), are some of the original compounds shown to evoke the classic signs of systemic inflammation/innate immune response and neuroinflammation. The term neuroinflammation often is used to infer the elaboration of proinflammatory mediators by microglia elicited by neuronal targeted activity. However, it also is possible that the microglia are responding to vasculature through several signaling mechanisms. Microglial activation relative to the vasculature in the hippocampus and parietal cortex was determined after an acute exposure of a single subcutaneous injection of 2 mg/kg LPS. Antibodies to allograft inflammatory factor (Aif1, a.k.a. Iba1) were used to track and quantify morphological changes in microglia. Immunostaining of platelet/endothelial cell adhesion molecule 1 (Pecam1, a.k.a. Cd31) was used to visualize vasculature in the forebrain and glial acidic fibrillary protein (GFAP) to visualize astrocytes. Neuroinflammation and other aspects of neurotoxicity were evaluated histologically at 3 h, 6 h, 12 h, 24 h, 3 d and 14 d following LPS exposure. LPS did not cause neurodegeneration as determined by Fluoro Jade C labeling. Also, there were no signs of mouse IgG leakage from brain vasculature due to LPS. Some changes in microglia size occurred at 6 h, but by 12 h microglial activation had begun with the combined soma and proximal processes size increasing significantly (1.5-fold). At 24 h, almost all the microglia soma and proximal processes in the hippocampus, parietal cortex, and thalamus were closely associated with the vasculature and had increased almost 2.0-fold in size. In many areas where microglia were juxtaposed to vasculature, astrocytic endfeet appeared to be displaced. The microglial activation had subsided slightly by 3 d with microglial size 1.6-fold that of control. We hypothesize that acute LPS activation can result in vascular mediated microglial responses through several mechanisms: 1) binding to Cd14 and Tlr4 receptors on microglia processes residing on vasculature; 2) damaging vasculature and causing the release of cytokines; and 3) possibly astrocytic endfeet damage resulting in cytokine release. These acute responses may serve as an adaptive mechanism to exposure to circulating LPS where the microglia surround the vasculature. This could further prevent the pathogen(s) circulating in blood from entering the brain. However, diverting microglial interactions away from synaptic remodeling and other types of microglial interactions with neurons may have adverse effects on neuronal function. |
Inhibition of calcium-calmodulin-dependent phosphodiesterase (PDE1) suppresses inflammatory responses
O'Brien JJ , O'Callaghan JP , Miller DB , Chalgeri S , Wennogle LP , Davis RE , Snyder GL , Hendrick JP . Mol Cell Neurosci 2019 102 103449 A novel, potent, and highly specific inhibitor of calcium-calmodulin-dependent phosphodiesterases (PDE) of the PDE1 family, ITI-214, was used to investigate the role of PDE1 in inflammatory responses. ITI-214 dose-dependently suppressed lipopolysaccharide (LPS)-induced gene expression of pro-inflammatory cytokines in an immortalized murine microglial cell line, BV2 cells. RNA profiling (RNA-Seq) was used to analyze the impact of ITI-214 on the BV2 cell transcriptome in the absence and the presence of LPS. ITI-214 was found to regulate classes of genes that are involved in inflammation and cell migration responses to LPS exposure. The gene expression changes seen with ITI-214 treatment were distinct from those elicited by inhibitors of other PDEs with anti-inflammatory activity (e.g., a PDE4 inhibitor), indicating a distinct mechanism of action for PDE1. Functionally, ITI-214 inhibited ADP-induced migration of BV2 cells through a P2Y12-receptor-dependent pathway, possibly due to increases in the extent of cAMP and VASP phosphorylation downstream of receptor activation. Importantly, this effect was recapitulated in P2 rat microglial cells in vitro, indicating that these pathways are active in native microglial cells. These studies are the first to demonstrate that inhibition of PDE1 exerts anti-inflammatory effects through effects on microglia signaling pathways. The ability of PDE1 inhibitors to prevent or dampen excessive inflammatory responses of BV2 cells and microglia provides a basis for exploring their therapeutic utility in the treatment of neurodegenerative diseases associated with increased inflammation and microglia proliferation such as Parkinson's disease and Alzheimer's disease. |
Neuroinflammation disorders exacerbated by environmental stressors
O'Callaghan JP , Miller DB . Metabolism 2019 100S 153951 Neuroinflammation is a condition characterized by the elaboration of proinflammatory mediators within the central nervous system. Neuroinflammation has emerged as a dominant theme in contemporary neuroscience due to its association with neurodegenerative disease states such as Alzheimer's disease, Parkinson's disease and Huntington's disease. While neuroinflammation often is associated with damage to the CNS, it also can occur in the absence of neurodegeneration, e. g., in association with systemic infection. The “acute phase” inflammatory response to tissue injury or infections instigates neuroinflammation-driven “sickness behavior,” i. e. a constellation of symptoms characterized by loss of appetite, fever, muscle pain, fatigue and cognitive problems. Typically, sickness behavior accompanies an inflammatory response that resolves quickly and serves to restore the body to homeostasis. However, recurring and sometimes chronic sickness behavior disorders can occur in the absence of an underlying cause or attendant neuropathology. Here, we review myalgic enchepalomyelitis/chronic fatigue syndrome (ME/CFS), Gulf War Illness (GWI), and chemobrain as examples of such disorders and propose that they can be exacerbated and perhaps initiated by a variety of environmental stressors. Diverse environmental stressors may disrupt the hypothalamic pituitary adrenal (HPA) axis and contribute to the degree and duration of a variety of neuroinflammation-driven diseases. |
Oligodendrocyte involvement in Gulf War Illness
Belgrad J , Dutta DJ , Bromley-Coolidge S , Kelly KA , Michalovicz LT , Sullivan KA , O'Callaghan JP , Fields RD . Glia 2019 67 (11) 2107-2124 Low level sarin nerve gas and other anti-cholinesterase agents have been implicated in Gulf War illness (GWI), a chronic multi-symptom disorder characterized by cognitive, pain and fatigue symptoms that continues to afflict roughly 32% of veterans from the 1990-1991 Gulf War. How disrupting cholinergic synaptic transmission could produce chronic illness is unclear, but recent research indicates that acetylcholine also mediates communication between axons and oligodendrocytes. Here we investigated the hypothesis that oligodendrocyte development is disrupted by Gulf War agents, by experiments using the sarin-surrogate acetylcholinesterase inhibitor, diisopropyl fluorophosphate (DFP). The effects of corticosterone, which is used in some GWI animal models, were also investigated. The data show that DFP decreased both the number of mature and dividing oligodendrocytes in the rat prefrontal cortex (PFC), but differences were found between PFC and corpus callosum. The differences seen between the PFC and corpus callosum likely reflect the higher percentage of proliferating oligodendroglia in the adult PFC. In cell culture, DFP also decreased oligodendrocyte survival through a non-cholinergic mechanism. Corticosterone promoted maturation of oligodendrocytes, and when used in combination with DFP it had protective effects by increasing the pool of mature oligodendrocytes and decreasing proliferation. Cell culture studies indicate direct effects of both DFP and corticosterone on OPCs, and by comparison with in vivo results, we conclude that in addition to direct effects, systemic effects and interruption of neuron-glia interactions contribute to the detrimental effects of GW agents on oligodendrocytes. Our results demonstrate that oligodendrocytes are an important component of the pathophysiology of GWI. |
Astrocyte-specific transcriptome analysis using the ALDH1L1 bacTRAP mouse reveals novel biomarkers of astrogliosis in response to neurotoxicity
Michalovicz LT , Kelly KA , Vashishtha S , Ben-Hamo R , Efroni S , Miller JV , Locker AR , Sullivan K , Broderick G , Miller DB , O'Callaghan JP . J Neurochem 2019 150 (4) 420-440 Neurotoxicology is hampered by the inability to predict regional and cellular targets of toxicant-induced damage. Evaluating astrogliosis overcomes this problem because reactive astrocytes highlight the location of toxicant-induced damage. While enhanced expression of glial fibrillary acidic protein is a hallmark of astrogliosis, few other biomarkers have been identified. However, bacterial artificial chromosome, translating ribosome affinity purification (bacTRAP) technology allows for characterization of the actively translating transcriptome of a particular cell type; use of this technology in aldehyde dehydrogenase 1 family member L1 (ALDH1L1) bacTRAP mice can identify genes selectively expressed in astrocytes. The aim of this study was to characterize additional biomarkers of neurotoxicity-induced astrogliosis using ALDH1L1 bacTRAP mice. The known dopaminergic neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 12.5 mg/kg s.c.) was used to induce astrogliosis. Striatal tissue was obtained 12, 24, and 48 hours following exposure for the isolation of actively translating RNA. Subsequently, MPTP-induced changes in this RNA pool were analyzed by microarray and 184 statistically significant, differentially expressed genes were identified. The data set was interrogated by gene ontology, pathway, and co-expression network analyses, which identified novel genes, as well as those with known immune and inflammatory functions. Using these analyses, we were directed to several genes associated with reactive astrocytes. Of these, TIMP1 and miR-147 were identified as candidate biomarkers due to their robust increased expression following both MPTP and trimethyl tin exposures. Thus, we have demonstrated that bacTRAP can be used to identify new biomarkers of astrogliosis and aid in the characterization of astrocyte phenotypes induced by toxicant exposures. This article is protected by copyright. All rights reserved. |
The multiple hit hypothesis for Gulf War Illness: Self-reported chemical/biological weapons exposure and mild traumatic brain injury
Janulewicz P , Krengel M , Quinn E , Heeren T , Toomey R , Killiany R , Zundel C , Ajama J , O'Callaghan J , Steele L , Klimas N , Sullivan K . Brain Sci 2018 8 (11) The Gulf War Illness Consortium (GWIC) was designed to identify objective biomarkers of Gulf War Illness (GWI) in 1991 Gulf War veterans. The symptoms of GWI include fatigue, pain, cognitive problems, gastrointestinal, respiratory, and skin problems. Neurotoxicant exposures during deployment, such as pesticides, sarin, and pyridostigmine bromide pills have been identified as contributors to GWI. We have also found an association between mild traumatic brain injury (mTBI) and increased rates of GWI. However, the combined impact of these physical and chemical exposures has not yet been explored in GWI. The objective of this study was to examine both self-reported mTBI and exposure to chemical/biological weapons (CBW) as a multiple or two hit model for increased risk of GWI and other chronic health conditions. The study population included 125 Gulf War (GW) veterans from the Boston GWIC. Exposure to CBW was reported in 47.2% of the study population, and 35.2% reported sustaining a mTBI during the war. Results confirmed that those with both exposures (mTBI and CBW) had higher rates of comorbid chronic health conditions while rates of GWI were equivalent for mTBI and CBW or mTBI alone. The timing of exposure to mTBI was found to be strikingly different between those with GWI and those without it. Correspondingly, 42.3% of GWI cases reported experiencing a mTBI during military service while none of the controls did (p = 0.0002). Rates of mTBI before and after the war did not differ between the cases and controls. In addition, 54% of cases compared to 14.3% of controls (p = <0.001) reported being exposed to CBW during military service. The current study examined the relation of the separate and combined effects of exposure to mTBI and CBW in 1991 GW veterans. The findings from this study suggest that both exposure to mTBI and CBW are associated with the development of GWI and multiple chronic health conditions and that combined exposure appears to lead to higher risk of chronic health effects. |
A Logic Model of Neuronal-Glial Interaction Suggests Altered Homeostatic Regulation in the Perpetuation of Neuroinflammation.
Craddock TJA , Michalovicz LT , Kelly KA , Rice MA Jr , Miller DB , Klimas NG , Morris M , O'Callaghan JP , Broderick G . Front Cell Neurosci 2018 12 336 Aberrant inflammatory signaling between neuronal and glial cells can develop into a persistent sickness behavior-related disorders, negatively impacting learning, memory, and neurogenesis. While there is an abundance of literature describing these interactions, there still lacks a comprehensive mathematical model describing the complex feed-forward and feedback mechanisms of neural-glial interaction. Here we compile molecular and cellular signaling information from various studies and reviews in the literature to create a logically-consistent, theoretical model of neural-glial interaction in the brain to explore the role of neuron-glia homeostatic regulation in the perpetuation of neuroinflammation. Logic rules are applied to this connectivity diagram to predict the system's homeostatic behavior. We validate our model predicted homeostatic profiles against RNAseq gene expression profiles in a mouse model of stress primed neuroinflammation. A meta-analysis was used to calculate the significance of similarity between the inflammatory profiles of mice exposed to diisopropyl fluorophostphate (DFP) [with and without prior priming by the glucocorticoid stress hormone corticosterone (CORT)], with the equilibrium states predicted by the model, and to provide estimates of the degree of the neuroinflammatory response. Beyond normal homeostatic regulation, our model predicts an alternate self-perpetuating condition consistent with chronic neuroinflammation. RNAseq gene expression profiles from the cortex of mice exposed to DFP and CORT+DFP align with this predicted state of neuroinflammation, whereas the alignment to CORT alone was negligible. Simulations of putative treatment strategies post-exposure were shown to be theoretically capable of returning the system to a state of typically healthy regulation with broad-acting anti-inflammatory agents showing the highest probability of success. The results support a role for the brain's own homeostatic drive in perpetuating the chronic neuroinflammation associated with exposure to the organophosphate DFP, with and without CORT priming. The deviation of illness profiles from exact model predictions suggests the presence of additional factors or of lasting changes to the brain's regulatory circuitry specific to each exposure. |
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