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Hobson BA, Rowland DJ, Dou Y, Saito N, Harmany ZT, Bruun DA, Harvey DJ, Chaudhari AJ, Garbow JR, Lein PJ. A longitudinal MRI and TSPO PET-based investigation of brain region-specific neuroprotection by diazepam versus midazolam following organophosphate-induced seizures. Neuropharmacology 2024; 251:109918. [PMID: 38527652 PMCID: PMC11250911 DOI: 10.1016/j.neuropharm.2024.109918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/01/2024] [Accepted: 03/13/2024] [Indexed: 03/27/2024]
Abstract
Acute poisoning with organophosphorus cholinesterase inhibitors (OPs), such as OP nerve agents and pesticides, can cause life threatening cholinergic crisis and status epilepticus (SE). Survivors often experience significant morbidity, including brain injury, acquired epilepsy, and cognitive deficits. Current medical countermeasures for acute OP poisoning include a benzodiazepine to mitigate seizures. Diazepam was long the benzodiazepine included in autoinjectors used to treat OP-induced seizures, but it is now being replaced in many guidelines by midazolam, which terminates seizures more quickly, particularly when administered intramuscularly. While a direct correlation between seizure duration and the extent of brain injury has been widely reported, there are limited data comparing the neuroprotective efficacy of diazepam versus midazolam following acute OP intoxication. To address this data gap, we used non-invasive imaging techniques to longitudinally quantify neuropathology in a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) with and without post-exposure intervention with diazepam or midazolam. Magnetic resonance imaging (MRI) was used to monitor neuropathology and brain atrophy, while positron emission tomography (PET) with a radiotracer targeting translocator protein (TSPO) was utilized to assess neuroinflammation. Animals were scanned at 3, 7, 28, 65, 91, and 168 days post-DFP and imaging metrics were quantitated for the hippocampus, amygdala, piriform cortex, thalamus, cerebral cortex and lateral ventricles. In the DFP-intoxicated rat, neuroinflammation persisted for the duration of the study coincident with progressive atrophy and ongoing tissue remodeling. Benzodiazepines attenuated neuropathology in a region-dependent manner, but neither benzodiazepine was effective in attenuating long-term neuroinflammation as detected by TSPO PET. Diffusion MRI and TSPO PET metrics were highly correlated with seizure severity, and early MRI and PET metrics were positively correlated with long-term brain atrophy. Collectively, these results suggest that anti-seizure therapy alone is insufficient to prevent long-lasting neuroinflammation and tissue remodeling.
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Affiliation(s)
- Brad A Hobson
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA; Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Yimeng Dou
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Naomi Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, California 95616, USA.
| | - Zachary T Harmany
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, California 95616, USA.
| | - Abhijit J Chaudhari
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA; Department of Radiology, University of California, Davis, School of Medicine, California 95817, USA.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Center, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, 63110, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
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2
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Almeida AJD, Hobson BA, Saito N, Bruun DA, Porter VA, Harvey DJ, Garbow JR, Chaudhari AJ, Lein PJ. Quantitative T 2 mapping-based longitudinal assessment of brain injury and therapeutic rescue in the rat following acute organophosphate intoxication. Neuropharmacology 2024; 249:109895. [PMID: 38437913 PMCID: PMC11227117 DOI: 10.1016/j.neuropharm.2024.109895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/07/2024] [Accepted: 02/29/2024] [Indexed: 03/06/2024]
Abstract
Acute intoxication with organophosphate (OP) cholinesterase inhibitors poses a significant public health risk. While currently approved medical countermeasures can improve survival rates, they often fail to prevent chronic neurological damage. Therefore, there is need to develop effective therapies and quantitative metrics for assessing OP-induced brain injury and its rescue by these therapies. In this study we used a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP), to test the hypothesis that T2 measures obtained from brain magnetic resonance imaging (MRI) scans provide quantitative metrics of brain injury and therapeutic efficacy. Adult male Sprague Dawley rats were imaged on a 7T MRI scanner at 3, 7 and 28 days post-exposure to DFP or vehicle (VEH) with or without treatment with the standard of care antiseizure drug, midazolam (MDZ); a novel antiseizure medication, allopregnanolone (ALLO); or combination therapy with MDZ and ALLO (DUO). Our results show that mean T2 values in DFP-exposed animals were: (1) higher than VEH in all volumes of interest (VOIs) at day 3; (2) decreased with time; and (3) decreased in the thalamus at day 28. Treatment with ALLO or DUO, but not MDZ alone, significantly decreased mean T2 values relative to untreated DFP animals in the piriform cortex at day 3. On day 28, the DUO group showed the most favorable T2 characteristics. This study supports the utility of T2 mapping for longitudinally monitoring brain injury and highlights the therapeutic potential of ALLO as an adjunct therapy to mitigate chronic morbidity associated with acute OP intoxication.
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Affiliation(s)
- Alita Jesal D Almeida
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Brad A Hobson
- Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Naomi Saito
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Valerie A Porter
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA.
| | - Joel R Garbow
- Department of Radiology, Washington University School of Medicine, St Louis, MO, 63110, USA.
| | - Abhijit J Chaudhari
- Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA; Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
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3
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Bernardino PN, Luo AS, Andrew PM, Unkel CM, Gonzalez MI, Gelli A, Lein PJ. Evidence Implicating Blood-Brain Barrier Impairment in the Pathogenesis of Acquired Epilepsy following Acute Organophosphate Intoxication. J Pharmacol Exp Ther 2024; 388:301-312. [PMID: 37827702 PMCID: PMC10801776 DOI: 10.1124/jpet.123.001836] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Abstract
Organophosphate (OP) poisoning can trigger cholinergic crisis, a life-threatening toxidrome that includes seizures and status epilepticus. These acute toxic responses are associated with persistent neuroinflammation and spontaneous recurrent seizures (SRS), also known as acquired epilepsy. Blood-brain barrier (BBB) impairment has recently been proposed as a pathogenic mechanism linking acute OP intoxication to chronic adverse neurologic outcomes. In this review, we briefly describe the cellular and molecular components of the BBB, review evidence of altered BBB integrity following acute OP intoxication, and discuss potential mechanisms by which acute OP intoxication may promote BBB dysfunction. We highlight the complex interplay between neuroinflammation and BBB dysfunction that suggests a positive feedforward interaction. Lastly, we examine research from diverse models and disease states that suggest mechanisms by which loss of BBB integrity may contribute to epileptogenic processes. Collectively, the literature identifies BBB impairment as a convergent mechanism of neurologic disease and justifies further mechanistic research into how acute OP intoxication causes BBB impairment and its role in the pathogenesis of SRS and potentially other long-term neurologic sequelae. Such research is critical for evaluating BBB stabilization as a neuroprotective strategy for mitigating OP-induced epilepsy and possibly seizure disorders of other etiologies. SIGNIFICANCE STATEMENT: Clinical and preclinical studies support a link between blood-brain barrier (BBB) dysfunction and epileptogenesis; however, a causal relationship has been difficult to prove. Mechanistic studies to delineate relationships between BBB dysfunction and epilepsy may provide novel insights into BBB stabilization as a neuroprotective strategy for mitigating epilepsy resulting from acute organophosphate (OP) intoxication and non-OP causes and potentially other adverse neurological conditions associated with acute OP intoxication, such as cognitive impairment.
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Affiliation(s)
- Pedro N Bernardino
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Audrey S Luo
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Peter M Andrew
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Chelsea M Unkel
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Marco I Gonzalez
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Angie Gelli
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, California (P.N.B., A.S.L., P.M.A., C.M.U., P.J.L.); Department of Neurology, University of California, Davis, School of Medicine, Sacramento, California (M.I.G.); and Department of Pharmacology, University of California, Davis, School of Medicine, Davis, California (A.G.)
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4
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Uzuegbunam BC, Rummel C, Librizzi D, Culmsee C, Hooshyar Yousefi B. Radiotracers for Imaging of Inflammatory Biomarkers TSPO and COX-2 in the Brain and in the Periphery. Int J Mol Sci 2023; 24:17419. [PMID: 38139248 PMCID: PMC10743508 DOI: 10.3390/ijms242417419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Inflammation involves the activation of innate immune cells and is believed to play an important role in the development and progression of both infectious and non-infectious diseases such as neurodegeneration, autoimmune diseases, pulmonary and cancer. Inflammation in the brain is marked by the upregulation of translocator protein (TSPO) in microglia. High TSPO levels are also found, for example, in macrophages in cases of rheumatoid arthritis and in malignant tumor cells compared to their relatively low physiological expression. The same applies for cyclooxgenase-2 (COX-2), which is constitutively expressed in the kidney, brain, thymus and gastrointestinal tract, but induced in microglia, macrophages and synoviocytes during inflammation. This puts TSPO and COX-2 in the spotlight as important targets for the diagnosis of inflammation. Imaging modalities, such as positron emission tomography and single-photon emission tomography, can be used to localize inflammatory processes and to track their progression over time. They could also enable the monitoring of the efficacy of therapy and predict its outcome. This review focuses on the current development of PET and SPECT tracers, not only for the detection of neuroinflammation, but also for emerging diagnostic measures in infectious and other non-infectious diseases such as rheumatic arthritis, cancer, cardiac inflammation and in lung diseases.
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Affiliation(s)
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, 35392 Gießen, Germany;
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
| | - Damiano Librizzi
- Department of Nuclear Medicine, Philipps University of Marburg, 35043 Marburg, Germany;
| | - Carsten Culmsee
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, 35037 Marburg, Germany
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5
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Bernardino PN, Hobson BA, Huddleston SL, Andrew PM, MacMahon JA, Saito NH, Porter VA, Bruun DA, Harvey DJ, Garbow JR, Gelli A, Chaudhari AJ, Lein PJ. Time- and region-dependent blood-brain barrier impairment in a rat model of organophosphate-induced status epilepticus. Neurobiol Dis 2023; 187:106316. [PMID: 37797902 PMCID: PMC11000668 DOI: 10.1016/j.nbd.2023.106316] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 10/07/2023] Open
Abstract
Acute organophosphate (OP) intoxication can trigger seizures that progress to status epilepticus (SE), and survivors often develop chronic morbidities, including spontaneous recurrent seizures (SRS). The pathogenic mechanisms underlying OP-induced SRS are unknown, but increased BBB permeability is hypothesized to be involved. Previous studies reported BBB leakage following OP-induced SE, but key information regarding time and regional distribution of BBB impairment during the epileptogenic period is missing. To address this data gap, we characterized the spatiotemporal progression of BBB impairment during the first week post-exposure in a rat model of diisopropylfluorophosphate-induced SE, using MRI and albumin immunohistochemistry. Increased BBB permeability, which was detected at 6 h and persisted up to 7 d post-exposure, was most severe and persistent in the piriform cortex and amygdala, moderate but persistent in the thalamus, and less severe and transient in the hippocampus and somatosensory cortex. The extent of BBB leakage was positively correlated with behavioral seizure severity, with the strongest association identified in the piriform cortex and amygdala. These findings provide evidence of the duration, magnitude and spatial breakdown of the BBB during the epileptogenic period following OP-induced SE and support BBB regulation as a viable therapeutic target for preventing SRS following acute OP intoxication.
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Affiliation(s)
- Pedro N Bernardino
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Brad A Hobson
- Center for Molecular and Genomic Imaging, University of California, Davis, Davis, CA 95616, USA.
| | - Sydney L Huddleston
- Center for Molecular and Genomic Imaging, University of California, Davis, Davis, CA 95616, USA.
| | - Peter M Andrew
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Jeremy A MacMahon
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Naomi H Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA 95616, USA.
| | - Valerie A Porter
- Department of Biomedical Engineering, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA 95616, USA.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Center, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, MO 63110, USA.
| | - Angie Gelli
- Department of Pharmacology, University of California, Davis, School of Medicine, Davis, CA 95616, USA.
| | - Abhijit J Chaudhari
- Center for Molecular and Genomic Imaging, University of California, Davis, Davis, CA 95616, USA; Department of Radiology, University of California, Davis, School of Medicine, Sacramento, CA 95817, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
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18F-Radiolabeled Translocator Protein (TSPO) PET Tracers: Recent Development of TSPO Radioligands and Their Application to PET Study. Pharmaceutics 2022; 14:pharmaceutics14112545. [PMID: 36432736 PMCID: PMC9697781 DOI: 10.3390/pharmaceutics14112545] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Translocator protein 18 kDa (TSPO) is a transmembrane protein in the mitochondrial membrane, which has been identified as a peripheral benzodiazepine receptor. TSPO is generally present at high concentrations in steroid-producing cells and plays an important role in steroid synthesis, apoptosis, and cell proliferation. In the central nervous system, TSPO expression is relatively modest under normal physiological circumstances. However, some pathological disorders can lead to changes in TSPO expression. Overexpression of TSPO is associated with several diseases, such as neurodegenerative diseases, neuroinflammation, brain injury, and cancers. TSPO has therefore become an effective biomarker of related diseases. Positron emission tomography (PET), a non-invasive molecular imaging technique used for the clinical diagnosis of numerous diseases, can detect diseases related to TSPO expression. Several radiolabeled TSPO ligands have been developed for PET. In this review, we describe recent advances in the development of TSPO ligands, and 18F-radiolabeled TSPO in particular, as PET tracers. This review covers pharmacokinetic studies, preclinical and clinical trials of 18F-labeled TSPO PET ligands, and the synthesis of TSPO ligands.
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7
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Schmidt CW. Hemispheres of Influence: Bridging the Disconnect between Environmental Neurotoxicology and Clinical Practice. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:52001. [PMID: 35543742 PMCID: PMC9093734 DOI: 10.1289/ehp9013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/23/2021] [Indexed: 06/14/2023]
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Mundy PC, Mendieta R, Lein PJ. Diisopropylfluorophosphate (DFP) volatizes and cross-contaminates wells in a common 96-well plate format used in zebrafish larvae toxicology studies. J Pharmacol Toxicol Methods 2022; 115:107173. [DOI: 10.1016/j.vascn.2022.107173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/23/2022] [Accepted: 05/01/2022] [Indexed: 11/27/2022]
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González EA, Calsbeek JJ, Tsai YH, Tang MY, Andrew P, Vu J, Berg EL, Saito NH, Harvey DJ, Supasai S, Gurkoff GG, Silverman JL, Lein PJ. Sex-specific acute and chronic neurotoxicity of acute diisopropylfluorophosphate (DFP)-intoxication in juvenile Sprague-Dawley rats. Curr Res Toxicol 2021; 2:341-356. [PMID: 34622217 PMCID: PMC8484742 DOI: 10.1016/j.crtox.2021.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/12/2022] Open
Abstract
Preclinical efforts to improve medical countermeasures against organophosphate (OP) chemical threat agents have largely focused on adult male models. However, age and sex have been shown to influence the neurotoxicity of repeated low-level OP exposure. Therefore, to determine the influence of sex and age on outcomes associated with acute OP intoxication, postnatal day 28 Sprague-Dawley male and female rats were exposed to the OP diisopropylfluorophosphate (DFP; 3.4 mg/kg, s.c.) or an equal volume of vehicle (∼80 µL saline, s.c.) followed by atropine sulfate (0.1 mg/kg, i.m.) and pralidoxime (2-PAM; 25 mg/kg, i.m.). Seizure activity was assessed during the first 4 h post-exposure using behavioral criteria and electroencephalographic (EEG) recordings. At 1 d post-exposure, acetylcholinesterase (AChE) activity was measured in cortical tissue, and at 1, 7, and 28 d post-exposure, brains were collected for neuropathologic analyses. At 1 month post-DFP, animals were analyzed for motor ability, learning and memory, and hippocampal neurogenesis. Acute DFP intoxication triggered more severe seizure behavior in males than females, which was supported by EEG recordings. DFP caused significant neurodegeneration and persistent microglial activation in numerous brain regions of both sexes, but astrogliosis occurred earlier and was more severe in males compared to females. DFP males and females exhibited pronounced memory deficits relative to sex-matched controls. In contrast, acute DFP intoxication altered hippocampal neurogenesis in males, but not females. These findings demonstrate that acute DFP intoxication triggers seizures in juvenile rats of both sexes, but the seizure severity varies by sex. Some, but not all, chronic neurotoxic outcomes also varied by sex. The spatiotemporal patterns of neurological damage suggest that microglial activation may be a more important factor than astrogliosis or altered neurogenesis in the pathogenesis of cognitive deficits in juvenile rats acutely intoxicated with OPs.
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Key Words
- 2-PAM, pralidoxime
- AChE, acetylcholinesterase
- AS, atropine-sulfate
- BChE, butyrylcholinesterase
- CT, computed tomography
- ChE, cholinesterase
- Cognitive deficits
- DFP, diisopropylfluorophosphate
- EEG, electroencephalogram
- FJC, Fluoro-Jade C
- Neurodegeneration
- Neurogenesis
- Neuroinflammation
- OP, organophosphate
- PBS, phosphate-buffered saline
- ROI, region of interest
- SE, status epilepticus
- Seizures
- Sex differences
- T2w, T2-weighted
- VEH, vehicle
- i.m., intramuscular
- i.p., intraperitoneal
- s.c., subcutaneous
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Affiliation(s)
- Eduardo A. González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Jonas J. Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Yi-Hua Tsai
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Mei-Yun Tang
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Peter Andrew
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Joan Vu
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Elizabeth L. Berg
- Department of Psychiatry, University of California, Davis, School of Medicine, 2230, Stockton Boulevard, Sacramento, CA 95817, USA
| | - Naomi H. Saito
- Department of Public Health Sciences, University of California, Davis, One Shields Avenue, School of Medicine, Davis, CA 95616, USA
| | - Danielle J. Harvey
- Department of Public Health Sciences, University of California, Davis, One Shields Avenue, School of Medicine, Davis, CA 95616, USA
| | - Suangsuda Supasai
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
| | - Gene G. Gurkoff
- Department of Neurological Surgery, University of California, Davis, School of Medicine, 4860 Y Street, Sacramento, CA 95817, USA
- Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA
| | - Jill L. Silverman
- Department of Psychiatry, University of California, Davis, School of Medicine, 2230, Stockton Boulevard, Sacramento, CA 95817, USA
- MIND Institute, University of California, Davis, 2825 50th Street, Sacramento, CA 95817, USA
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA
- MIND Institute, University of California, Davis, 2825 50th Street, Sacramento, CA 95817, USA
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10
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Calsbeek JJ, González EA, Bruun DA, Guignet MA, Copping N, Dawson ME, Yu AJ, MacMahon JA, Saito NH, Harvey DJ, Silverman JL, Lein PJ. Persistent neuropathology and behavioral deficits in a mouse model of status epilepticus induced by acute intoxication with diisopropylfluorophosphate. Neurotoxicology 2021; 87:106-119. [PMID: 34509511 PMCID: PMC8595753 DOI: 10.1016/j.neuro.2021.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/27/2021] [Accepted: 09/06/2021] [Indexed: 01/01/2023]
Abstract
Organophosphate (OP) nerve agents and pesticides are a class of neurotoxic compounds that can cause status epilepticus (SE), and death following acute high-dose exposures. While the standard of care for acute OP intoxication (atropine, oxime, and high-dose benzodiazepine) can prevent mortality, survivors of OP poisoning often experience long-term brain damage and cognitive deficits. Preclinical studies of acute OP intoxication have primarily used rat models to identify candidate medical countermeasures. However, the mouse offers the advantage of readily available knockout strains for mechanistic studies of acute and chronic consequences of OP-induced SE. Therefore, the main objective of this study was to determine whether a mouse model of acute diisopropylfluorophosphate (DFP) intoxication would produce acute and chronic neurotoxicity similar to that observed in rat models and humans following acute OP intoxication. Adult male C57BL/6J mice injected with DFP (9.5 mg/kg, s.c.) followed 1 min later with atropine sulfate (0.1 mg/kg, i.m.) and 2-pralidoxime (25 mg/kg, i.m.) developed behavioral and electrographic signs of SE within minutes that continued for at least 4 h. Acetylcholinesterase inhibition persisted for at least 3 d in the blood and 14 d in the brain of DFP mice relative to vehicle (VEH) controls. Immunohistochemical analyses revealed significant neurodegeneration and neuroinflammation in multiple brain regions at 1, 7, and 28 d post-exposure in the brains of DFP mice relative to VEH controls. Deficits in locomotor and home-cage behavior were observed in DFP mice at 28 d post-exposure. These findings demonstrate that this mouse model replicates many of the outcomes observed in rats and humans acutely intoxicated with OPs, suggesting the feasibility of using this model for mechanistic studies and therapeutic screening.
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Affiliation(s)
- Jonas J Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Eduardo A González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Michelle A Guignet
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Nycole Copping
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
| | - Mallory E Dawson
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Alexandria J Yu
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Jeremy A MacMahon
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Naomi H Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
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11
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Calsbeek JJ, González EA, Boosalis CA, Zolkowska D, Bruun DA, Rowland DJ, Saito NH, Harvey DJ, Chaudhari AJ, Rogawski MA, Garbow JR, Lein PJ. Strain differences in the extent of brain injury in mice after tetramethylenedisulfotetramine-induced status epilepticus. Neurotoxicology 2021; 87:43-50. [PMID: 34478772 PMCID: PMC8595842 DOI: 10.1016/j.neuro.2021.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/28/2021] [Accepted: 08/29/2021] [Indexed: 11/30/2022]
Abstract
Acute intoxication with tetramethylenedisulfotetramine (TETS) can trigger status epilepticus (SE) in humans. Survivors often exhibit long-term neurological effects, including electrographic abnormalities and cognitive deficits, but the pathogenic mechanisms linking the acute toxic effects of TETS to chronic outcomes are not known. Here, we use advanced in vivo imaging techniques to longitudinally monitor the neuropathological consequences of TETS-induced SE in two different mouse strains. Adult male NIH Swiss and C57BL/6J mice were injected with riluzole (10 mg/kg, i.p.), followed 10 min later by an acute dose of TETS (0.2 mg/kg in NIH Swiss; 0.3 mg/kg, i.p. in C57BL/6J) or an equal volume of vehicle (10% DMSO in 0.9% sterile saline). Different TETS doses were administered to trigger comparable seizure behavior between strains. Seizure behavior began within minutes of TETS exposure and rapidly progressed to SE that was terminated after 40 min by administration of midazolam (1.8 mg/kg, i.m.). The brains of vehicle and TETS-exposed mice were imaged using in vivo magnetic resonance (MR) and translocator protein (TSPO) positron emission tomography (PET) at 1, 3, 7, and 14 days post-exposure to monitor brain injury and neuroinflammation, respectively. When the brain scans of TETS mice were compared to those of vehicle controls, subtle and transient neuropathology was observed in both mouse strains, but more extensive and persistent TETS-induced neuropathology was observed in C57BL/6J mice. In addition, one NIH Swiss TETS mouse that did not respond to the midazolam therapy, but remained in SE for more than 2 h, displayed robust neuropathology as determined by in vivo imaging and confirmed by FluoroJade C staining and IBA-1 immunohistochemistry as readouts of neurodegeneration and neuroinflammation, respectively. These findings demonstrate that the extent of injury observed in the mouse brain after TETS-induced SE varied according to strain, dose of TETS and/or the duration of SE. These observations suggest that TETS-intoxicated humans who do not respond to antiseizure medication are at increased risk for brain injury.
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Affiliation(s)
- Jonas J Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Eduardo A González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Casey A Boosalis
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Dorota Zolkowska
- Department of Neurology, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA, 95616, USA.
| | - Naomi H Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Abhijit J Chaudhari
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA, 95616, USA.
| | - Michael A Rogawski
- Department of Neurology, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, 63110, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
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12
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Abstract
The canonical mechanism of organophosphate (OP) neurotoxicity is the inhibition of acetylcholinesterase (AChE). However, multiple lines of evidence suggest that mechanisms in addition to or other than AChE inhibition contribute to the neurotoxic effects associated with acute and chronic OP exposures. Characterizing the role(s) of AChE inhibition versus noncholinergic mechanisms in OP neurotoxicity remains an active area of research with significant diagnostic and therapeutic implications. Here, we review recently published studies that provide mechanistic insights regarding (1) OP-induced status epilepticus, (2) long-term neurologic consequences of acute OP exposures, and (3) neurotoxic effects associated with repeated low-level OP exposures. Key data gaps and challenges are also discussed.
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Affiliation(s)
- Yi-Hua Tsai
- Department of Molecular Sciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Sciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
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13
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Andrew PM, Lein PJ. Neuroinflammation as a Therapeutic Target for Mitigating the Long-Term Consequences of Acute Organophosphate Intoxication. Front Pharmacol 2021; 12:674325. [PMID: 34054549 PMCID: PMC8153682 DOI: 10.3389/fphar.2021.674325] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/30/2021] [Indexed: 12/14/2022] Open
Abstract
Acute intoxication with organophosphates (OPs) can cause a potentially fatal cholinergic crisis characterized by peripheral parasympathomimetic symptoms and seizures that rapidly progress to status epilepticus (SE). While current therapeutic countermeasures for acute OP intoxication significantly improve the chances of survival when administered promptly, they are insufficient for protecting individuals from chronic neurologic outcomes such as cognitive deficits, affective disorders, and acquired epilepsy. Neuroinflammation is posited to contribute to the pathogenesis of these long-term neurologic sequelae. In this review, we summarize what is currently known regarding the progression of neuroinflammatory responses after acute OP intoxication, drawing parallels to other models of SE. We also discuss studies in which neuroinflammation was targeted following OP-induced SE, and explain possible reasons why such therapeutic interventions have inconsistently and only partially improved long-term outcomes. Finally, we suggest future directions for the development of therapeutic strategies that target neuroinflammation to mitigate the neurologic sequelae of acute OP intoxication.
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Affiliation(s)
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, United States
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14
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Zürcher NR, Loggia ML, Mullett JE, Tseng C, Bhanot A, Richey L, Hightower BG, Wu C, Parmar AJ, Butterfield RI, Dubois JM, Chonde DB, Izquierdo-Garcia D, Wey HY, Catana C, Hadjikhani N, McDougle CJ, Hooker JM. [ 11C]PBR28 MR-PET imaging reveals lower regional brain expression of translocator protein (TSPO) in young adult males with autism spectrum disorder. Mol Psychiatry 2021; 26:1659-1669. [PMID: 32076115 PMCID: PMC8159742 DOI: 10.1038/s41380-020-0682-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 01/12/2020] [Accepted: 02/06/2020] [Indexed: 12/19/2022]
Abstract
Mechanisms of neuroimmune and mitochondrial dysfunction have been repeatedly implicated in autism spectrum disorder (ASD). To examine these mechanisms in ASD individuals, we measured the in vivo expression of the 18 kDa translocator protein (TSPO), an activated glial marker expressed on mitochondrial membranes. Participants underwent scanning on a simultaneous magnetic resonance-positron emission tomography (MR-PET) scanner with the second-generation TSPO radiotracer [11C]PBR28. By comparing TSPO in 15 young adult males with ASD with 18 age- and sex-matched controls, we showed that individuals with ASD exhibited lower regional TSPO expression in several brain regions, including the bilateral insular cortex, bilateral precuneus/posterior cingulate cortex, and bilateral temporal, angular, and supramarginal gyri, which have previously been implicated in autism in functional MR imaging studies. No brain region exhibited higher regional TSPO expression in the ASD group compared with the control group. A subset of participants underwent a second MR-PET scan after a median interscan interval of 3.6 months, and we determined that TSPO expression over this period of time was stable and replicable. Furthermore, voxelwise analysis confirmed lower regional TSPO expression in ASD at this later time point. Lower TSPO expression in ASD could reflect abnormalities in neuroimmune processes or mitochondrial dysfunction.
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Affiliation(s)
- N R Zürcher
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
- Harvard Medical School, Boston, MA, USA.
| | - M L Loggia
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - J E Mullett
- Lurie Center for Autism, Massachusetts General Hospital, Lexington, MA, USA
| | - C Tseng
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - A Bhanot
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - L Richey
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - B G Hightower
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - C Wu
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - A J Parmar
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - R I Butterfield
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - J M Dubois
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - D B Chonde
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - D Izquierdo-Garcia
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - H Y Wey
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - C Catana
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - N Hadjikhani
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Harvard Medical School, Boston, MA, USA
- Gillberg Neuropsychiatry Center, University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden
| | - C J McDougle
- Harvard Medical School, Boston, MA, USA
- Lurie Center for Autism, Massachusetts General Hospital, Lexington, MA, USA
| | - J M Hooker
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
- Harvard Medical School, Boston, MA, USA.
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15
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Positron Emission Tomography Imaging of Macrophages in Cancer. Cancers (Basel) 2021; 13:cancers13081921. [PMID: 33923410 PMCID: PMC8072570 DOI: 10.3390/cancers13081921] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 12/14/2022] Open
Abstract
Macrophages are large phagocytic cells that can be classified as a type of white blood cell and may be either mobile or stationary in tissues. The presence of macrophages in essentially every major disease makes them attractive candidates to serve as therapeutic targets and diagnostic biomarkers. Macrophages that are found in the microenvironment of solid tumors are referred to as tumor-associated macrophages (TAMs) and have been shown to influence chemoresistance, immune regulation, tumor initiation and tumor growth. The imaging of TAMs through Positron Emission Tomography (PET) has the potential to provide valuable information on cancer biology, tumor progression, and response to therapy. This review will highlight the versatility of macrophage imaging in cancer through the use of PET.
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16
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Patten KT, González EA, Valenzuela A, Berg E, Wallis C, Garbow JR, Silverman JL, Bein KJ, Wexler AS, Lein PJ. Effects of early life exposure to traffic-related air pollution on brain development in juvenile Sprague-Dawley rats. Transl Psychiatry 2020; 10:166. [PMID: 32483143 PMCID: PMC7264203 DOI: 10.1038/s41398-020-0845-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022] Open
Abstract
Epidemiological studies link traffic-related air pollution (TRAP) to increased risk for various neurodevelopmental disorders (NDDs); however, there are limited preclinical data demonstrating a causal relationship between TRAP and adverse neurodevelopmental outcomes. Moreover, much of the preclinical literature reports effects of concentrated ambient particles or diesel exhaust that do not recapitulate the complexity of real-world TRAP exposures. To assess the developmental neurotoxicity of more realistic TRAP exposures, we exposed male and female rats during gestation and early postnatal development to TRAP drawn directly from a traffic tunnel in Northern California and delivered to animals in real-time. We compared NDD-relevant neuropathological outcomes at postnatal days 51-55 in TRAP-exposed animals versus control subjects exposed to filtered air. As indicated by immunohistochemical analyses, TRAP significantly increased microglial infiltration in the CA1 hippocampus, but decreased astrogliosis in the dentate gyrus. TRAP exposure had no persistent effect on pro-inflammatory cytokine levels in the male or female brain, but did significantly elevate the anti-inflammatory cytokine IL-10 in females. In male rats, TRAP significantly increased hippocampal neurogenesis, while in females, TRAP increased granule cell layer width. TRAP had no effect on apoptosis in either sex. Magnetic resonance imaging revealed that TRAP-exposed females, but not males, also exhibited decreased lateral ventricular volume, which was correlated with increased granule cell layer width in the hippocampus in females. Collectively, these data indicate that exposure to real-world levels of TRAP during gestation and early postnatal development modulate neurodevelopment, corroborating epidemiological evidence of an association between TRAP exposure and increased risk of NDDs.
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Affiliation(s)
- Kelley T Patten
- Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, USA
| | - Eduardo A González
- Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, USA
| | - Anthony Valenzuela
- Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, USA
| | - Elizabeth Berg
- Psychiatry, UC Davis School of Medicine, Sacramento, CA, USA
| | | | - Joel R Garbow
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Jill L Silverman
- Psychiatry, UC Davis School of Medicine, Sacramento, CA, USA
- The MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA
| | - Keith J Bein
- Air Quality Research Center, UC Davis, Davis, CA, USA
- Center for Health and the Environment, UC Davis, Davis, CA, USA
| | - Anthony S Wexler
- Air Quality Research Center, UC Davis, Davis, CA, USA
- Mechanical and Aerospace Engineering, Civil and Environmental Engineering, and Land, Air and Water Resources, UC Davis, Davis, CA, USA
| | - Pamela J Lein
- Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, USA.
- The MIND Institute, UC Davis School of Medicine, Sacramento, CA, USA.
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17
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Petkova SP, Pride M, Klocke C, Fenton TA, White J, Lein PJ, Ellegood J, Lerch JP, Silverman JL, Waldau B. Cyclin D2-knock-out mice with attenuated dentate gyrus neurogenesis have robust deficits in long-term memory formation. Sci Rep 2020; 10:8204. [PMID: 32424171 PMCID: PMC7235216 DOI: 10.1038/s41598-020-65090-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/23/2020] [Indexed: 02/07/2023] Open
Abstract
Neurobehavioral studies have produced contradictory findings concerning the function of neurogenesis in the adult dentate gyrus. Previous studies have proved inconsistent across several behavioral endpoints thought to be dependent on dentate neurogenesis, including memory acquisition, short-term and long-term retention of memory, pattern separation, and reversal learning. We hypothesized that the main function of dentate neurogenesis is long-term memory formation because we assumed that a newly formed and integrated neuron would have a long-term impact on the local neural network. We used a cyclin D2-knock-out (cyclin D2−/−) mouse model of endogenously deficient dentate neurogenesis to test this hypothesis. We found that cyclin D2−/− mice had robust and sustained loss of long-term memory in two separate behavioral tasks, Morris water maze (MWM) and touchscreen intermediate pattern separation. Moreover, after adjusting for differences in brain volumes determined by magnetic resonance (MR) imaging, reduced dentate neurogenesis moderately correlated with deficits in memory retention after 24 hours. Importantly, cyclin D2−/− mice did not show deficits in learning acquisition in a touchscreen paradigm of intermediate pattern separation or MWM platform location, indicating intact short-term memory. Further evaluation of cyclin D2−/− mice is necessary to confirm that deficits are specifically linked to dentate gyrus neurogenesis since cyclin D2−/− mice also have a reduced size of the olfactory bulb, hippocampus, cerebellum and cortex besides reduced dentate gyrus neurogenesis.
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Affiliation(s)
- Stela P Petkova
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, US
| | - Michael Pride
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, US
| | - Carolyn Klocke
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, 95616, US
| | - Timothy A Fenton
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, US
| | - Jeannine White
- Institute for Regenerative Cures, Sacramento, CA, 95817, US
| | - Pamela J Lein
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA, 95616, US.,MIND Institute, UC Davis, Sacramento, CA, 95817, US
| | - Jacob Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, M5T 3H7, Canada
| | - Jason P Lerch
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, M5T 3H7, Canada.,Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neuroscience,The University of Oxford, Oxford, OX3 9DU, UK
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, University of California Davis School of Medicine, Sacramento, CA, 95817, US.,MIND Institute, UC Davis, Sacramento, CA, 95817, US
| | - Ben Waldau
- Department of Neurological Surgery, UC Davis Medical Center, Sacramento, CA, 95817, US.
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18
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Yang J, Bruun DA, Wang C, Wan D, McReynolds CB, Phu K, Inceoglu B, Lein PJ, Hammock BD. Lipidomes of brain from rats acutely intoxicated with diisopropylfluorophosphate identifies potential therapeutic targets. Toxicol Appl Pharmacol 2019; 382:114749. [PMID: 31521729 PMCID: PMC6957308 DOI: 10.1016/j.taap.2019.114749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/30/2019] [Accepted: 09/07/2019] [Indexed: 01/28/2023]
Abstract
Organophosphates (OPs), a class of phosphorus-containing chemicals that act by disrupting cholinergic transmission, include both toxic and fast-acting chemical warfare agents as well as less toxic but more easily accessible OP pesticides. The classical atropine/2-PAM antidote fails to protect against long-term symptoms following acute intoxication with OPs at levels that trigger status epilepticus. Acute OP intoxication also causes a robust neuroinflammatory response, which is implicated in the pathogenesis of long-term effects. In this study, we characterized the profiles of lipid mediators, important players in neuroinflammation, in the rat model of acute DFP intoxication. The profiles of lipid mediators were monitored in three different regions of the brain (cortex, hippocampus, and cerebellum) at 0, 1, 3, 7, 14, and 28 days post-exposure. The distribution pattern of lipid mediators was distinct in the three brain regions. In the cerebellum, the profile is dominated by LOX metabolites, while the lipid mediator profiles in cortex and hippocampus are dominated by COX metabolites followed by LOX and CYP 450 metabolites. Following acute DFP intoxication, most of the pro-inflammatory lipid mediators (e.g., PGD2 and PGE2) increased rapidly from day 1, while the concentrations of some anti-inflammatory lipid mediators (e.g. 14,15 EpETrE) decreased after DFP intoxication but recovered by day 14 post-exposure. The lipidomics results suggest two potential treatment targets: blocking the formation of prostaglandins by inhibiting COX and stabilizing the anti-inflammatory lipid mediators containing epoxides by inhibiting the enzyme soluble epoxide hydrolase (sEH).
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Affiliation(s)
- Jun Yang
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Chang Wang
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA; School of Radiation Medicine and Protection, Medical College of Soochow University, School for Radiological and Interdisciplinary Sciences (RAD-X), Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, PR China
| | - Debin Wan
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Cindy B McReynolds
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Kenny Phu
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Bora Inceoglu
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Bruce D Hammock
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA.
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