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Currim F, Tanwar R, Brown-Leung JM, Paranjape N, Liu J, Sanders LH, Doorn JA, Cannon JR. Selective dopaminergic neurotoxicity modulated by inherent cell-type specific neurobiology. Neurotoxicology 2024; 103:266-287. [PMID: 38964509 DOI: 10.1016/j.neuro.2024.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/06/2024]
Abstract
Parkinson's disease (PD) is a debilitating neurodegenerative disease affecting millions of individuals worldwide. Hallmark features of PD pathology are the formation of Lewy bodies in neuromelanin-containing dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNpc), and the subsequent irreversible death of these neurons. Although genetic risk factors have been identified, around 90 % of PD cases are sporadic and likely caused by environmental exposures and gene-environment interaction. Mechanistic studies have identified a variety of chemical PD risk factors. PD neuropathology occurs throughout the brain and peripheral nervous system, but it is the loss of DAergic neurons in the SNpc that produce many of the cardinal motor symptoms. Toxicology studies have found specifically the DAergic neuron population of the SNpc exhibit heightened sensitivity to highly variable chemical insults (both in terms of chemical structure and mechanism of neurotoxic action). Thus, it has become clear that the inherent neurobiology of nigral DAergic neurons likely underlies much of this neurotoxic response to broad insults. This review focuses on inherent neurobiology of nigral DAergic neurons and how such neurobiology impacts the primary mechanism of neurotoxicity. While interactions with a variety of other cell types are important in disease pathogenesis, understanding how inherent DAergic biology contributes to selective sensitivity and primary mechanisms of neurotoxicity is critical to advancing the field. Specifically, key biological features of DAergic neurons that increase neurotoxicant susceptibility.
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Affiliation(s)
- Fatema Currim
- School of Health Sciences, Purdue University, West Lafayette, IN 47901, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47901, USA
| | - Reeya Tanwar
- School of Health Sciences, Purdue University, West Lafayette, IN 47901, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47901, USA
| | - Josephine M Brown-Leung
- School of Health Sciences, Purdue University, West Lafayette, IN 47901, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47901, USA
| | - Neha Paranjape
- Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA
| | - Jennifer Liu
- Departments of Neurology and Pathology, Duke University School of Medicine, Durham, NC 27710, USA; Duke Center for Neurodegeneration and Neurotherapeutics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Laurie H Sanders
- Departments of Neurology and Pathology, Duke University School of Medicine, Durham, NC 27710, USA; Duke Center for Neurodegeneration and Neurotherapeutics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jonathan A Doorn
- Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA
| | - Jason R Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN 47901, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47901, USA.
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2
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Wilson RJ, Suh YP, Dursun I, Li X, da Costa Souza F, Grodzki AC, Cui JY, Lehmler HJ, Lein PJ. Developmental exposure to the Fox River PCB mixture modulates behavior in juvenile mice. Neurotoxicology 2024; 103:146-161. [PMID: 38885884 DOI: 10.1016/j.neuro.2024.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/13/2024] [Accepted: 06/11/2024] [Indexed: 06/20/2024]
Abstract
Developmental exposures to PCBs are implicated in the etiology of neurodevelopmental disorders (NDDs). This observation is concerning given the continued presence of PCBs in the human environment and the increasing incidence of NDDs. Previous studies reported that developmental exposure to legacy commercial PCB mixtures (Aroclors) or single PCB congeners found in Aroclors caused NDD-relevant behavioral phenotypes in animal models. However, the PCB congener profile in contemporary human samples is dissimilar to that of the legacy Aroclors, raising the question of whether human-relevant PCB mixtures similarly interfere with normal brain development. To address this question, we assessed the developmental neurotoxicity of the Fox River Mixture (FRM), which was designed to mimic the congener profile identified in fish from the PCB-contaminated Fox River that constitute a primary protein source in the diet of surrounding communities. Adult female C57BL/6 J mouse dams (8-10 weeks old) were exposed to vehicle (peanut oil) or FRM at 0.1, 1.0, or 6.0 mg/kg/d in their diet throughout gestation and lactation, and neurodevelopmental outcomes were assessed in their pups. Ultrasonic vocalizations (USVs) and measures of general development were quantified at postnatal day (P) 7, while performance in the spontaneous alternation task and the 3-chambered social approach/social novelty task was assessed on P35. Triiodothyronine (T3) and thyroxine (T4) were quantified in serum collected from the dams when pups were weaned and from pups on P28 and P35. Developmental exposure to FRM did not alter pup weight or body temperature on P7, but USVs were significantly decreased in litters exposed to FRM at 0.1 or 6.0 mg/kg/d in the maternal diet. FRM also impaired male and female pups' performance in the social novelty task. Compared to sex-matched vehicles, significantly decreased social novelty was observed in male and female pups in the 0.1 and 6.0 mg/kg/d dose groups. FRM did not alter performance in the spontaneous alternation or social approach tasks. FRM increased serum T3 levels but decreased serum T4 levels in P28 male pups in the 1.0 and 6.0 mg/kg/d dose groups. In P35 female pups and dams, serum T3 levels decreased in the 6.0 mg/kg/d dose group while T4 levels were not altered. Collectively, these findings suggest that FRM interferes with the development of social communication and social novelty, but not memory, supporting the hypothesis that contemporary PCB exposures pose a risk to the developing brain. FRM had sex, age, and dose-dependent effects on serum thyroid hormone levels that overlapped but did not perfectly align with the FRM effects on behavioral outcomes. These observations suggest that changes in thyroid hormone levels are not likely the major factor underlying the behavioral deficits observed in FRM-exposed animals.
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Affiliation(s)
- Rebecca J Wilson
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA
| | - Youjun P Suh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Ilknur Dursun
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA; Istinye University, School of Medicine, Department of Physiology, Istanbul 34396, Turkey
| | - Xueshu Li
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA
| | | | - Ana Cristina Grodzki
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA
| | - Julia Y Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California Davis, Davis, CA, USA.
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3
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Keil-Stietz K, Lein PJ. Gene×environment interactions in autism spectrum disorders. Curr Top Dev Biol 2022; 152:221-284. [PMID: 36707213 PMCID: PMC10496028 DOI: 10.1016/bs.ctdb.2022.11.001] [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] [Indexed: 12/24/2022]
Abstract
There is credible evidence that environmental factors influence individual risk and/or severity of autism spectrum disorders (hereafter referred to as autism). While it is likely that environmental chemicals contribute to the etiology of autism via multiple mechanisms, identifying specific environmental factors that confer risk for autism and understanding how they contribute to the etiology of autism has been challenging, in part because the influence of environmental chemicals likely varies depending on the genetic substrate of the exposed individual. Current research efforts are focused on elucidating the mechanisms by which environmental chemicals interact with autism genetic susceptibilities to adversely impact neurodevelopment. The goal is to not only generate insights regarding the pathophysiology of autism, but also inform the development of screening platforms to identify specific environmental factors and gene×environment (G×E) interactions that modify autism risk. Data from such studies are needed to support development of intervention strategies for mitigating the burden of this neurodevelopmental condition on individuals, their families and society. In this review, we discuss environmental chemicals identified as putative autism risk factors and proposed mechanisms by which G×E interactions influence autism risk and/or severity using polychlorinated biphenyls (PCBs) as an example.
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Affiliation(s)
- Kimberly Keil-Stietz
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, United States.
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4
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Kennedy CL, Spiegelhoff A, Lavery T, Wang K, Manuel RSJ, Wang Z, Wildermuth H, Keil Stietz KP. Developmental polychlorinated biphenyl (PCB) exposure alters voiding physiology in young adult male and female mice. AMERICAN JOURNAL OF CLINICAL AND EXPERIMENTAL UROLOGY 2022; 10:82-97. [PMID: 35528463 PMCID: PMC9077147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
The impact of developmental exposure to environmental chemicals on lower urinary tract function is not well understood, despite the fact that these chemicals could contribute to etiologically complex lower urinary tract symptoms (LUTS). Polychlorinated biphenyls (PCBs) are environmental toxicants known to be detrimental to the central nervous system, but their impact on voiding function in mouse models is not known. Therefore, we test whether developmental exposure to PCBs is capable of altering voiding physiology in young adult mice. C57Bl/6J female mice received a daily oral dose of the MARBLES PCB mixture for two weeks prior to mating and through gestation and lactation. The mixture mimics the profile of PCBs found in a contemporary population of pregnant women. Voiding function was then tested in young adult offspring using void spot assay, uroflowmetry and anesthetized cystometry. PCB effects were sex and dose dependent. Overall, PCBs led to increases in small size urine spots in both sexes with males producing more drop-like voids and greater peak pressure during a voiding cycle while females displayed decreases in void duration and intervoid interval. Together, these results indicate that developmental exposure to PCBs are capable of altering voiding physiology in young adult mice. Further work to identify the underlying mechanisms driving these changes may help develop more effective preventative or therapeutic strategies for LUTS.
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Affiliation(s)
- Conner L Kennedy
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Audrey Spiegelhoff
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Thomas Lavery
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Kathy Wang
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Robbie SJ Manuel
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Zunyi Wang
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Hannah Wildermuth
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Kimberly P Keil Stietz
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonMadison, WI 53706, USA
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5
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Laufer BI, Neier K, Valenzuela AE, Yasui DH, Schmidt RJ, Lein PJ, LaSalle JM. Placenta and fetal brain share a neurodevelopmental disorder DNA methylation profile in a mouse model of prenatal PCB exposure. Cell Rep 2022; 38:110442. [PMID: 35235788 PMCID: PMC8941983 DOI: 10.1016/j.celrep.2022.110442] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/19/2021] [Accepted: 02/03/2022] [Indexed: 12/27/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are developmental neurotoxicants implicated as environmental risk factors for neurodevelopmental disorders (NDDs). Here, we report the effects of prenatal exposure to a human-relevant mixture of PCBs on the DNA methylation profiles of mouse placenta and fetal brain. Thousands of differentially methylated regions (DMRs) distinguish placenta and fetal brain from PCB-exposed mice from sex-matched vehicle controls. In both placenta and fetal brain, PCB-associated DMRs are enriched for functions related to neurodevelopment and cellular signaling and enriched within regions of bivalent chromatin. The placenta and brain PCB DMRs overlap significantly and map to a shared subset of genes enriched for Wnt signaling, Slit/Robo signaling, and genes differentially expressed in NDD models. The consensus PCB DMRs also significantly overlap with DMRs from human NDD brain and placenta. These results demonstrate that PCB-exposed placenta contains a subset of DMRs that overlap fetal brain DMRs relevant to an NDD.
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Affiliation(s)
- Benjamin I Laufer
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, CA 95616, USA; UC Davis Genome Center, University of California, Davis, Davis, CA 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Kari Neier
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, CA 95616, USA; UC Davis Genome Center, University of California, Davis, Davis, CA 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA; Perinatal Origins of Disparities Center, University of California, Davis, Davis, CA 95616, USA
| | - Anthony E Valenzuela
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Dag H Yasui
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, CA 95616, USA; UC Davis Genome Center, University of California, Davis, Davis, CA 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Rebecca J Schmidt
- MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA; Perinatal Origins of Disparities Center, University of California, Davis, Davis, CA 95616, USA; Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Pamela J Lein
- MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA; Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Janine M LaSalle
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, Davis, CA 95616, USA; UC Davis Genome Center, University of California, Davis, Davis, CA 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA; Perinatal Origins of Disparities Center, University of California, Davis, Davis, CA 95616, USA.
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6
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Keil Stietz KP, Sethi S, Klocke CR, de Ruyter TE, Wilson MD, Pessah IN, Lein PJ. Sex and Genotype Modulate the Dendritic Effects of Developmental Exposure to a Human-Relevant Polychlorinated Biphenyls Mixture in the Juvenile Mouse. Front Neurosci 2021; 15:766802. [PMID: 34924936 PMCID: PMC8678536 DOI: 10.3389/fnins.2021.766802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/04/2021] [Indexed: 11/23/2022] Open
Abstract
While many neurodevelopmental disorders (NDDs) are thought to result from interactions between environmental and genetic risk factors, the identification of specific gene-environment interactions that influence NDD risk remains a critical data gap. We tested the hypothesis that polychlorinated biphenyls (PCBs) interact with human mutations that alter the fidelity of neuronal Ca2+ signaling to confer NDD risk. To test this, we used three transgenic mouse lines that expressed human mutations known to alter Ca2+ signals in neurons: (1) gain-of-function mutation in ryanodine receptor-1 (T4826I-RYR1); (2) CGG-repeat expansion in the 5′ non-coding portion of the fragile X mental retardation gene 1 (FMR1); and (3) a double mutant (DM) that expressed both mutations. Transgenic and wildtype (WT) mice were exposed throughout gestation and lactation to the MARBLES PCB mix at 0.1, 1, or 6 mg/kg in the maternal diet. The MARBLES mix simulates the relative proportions of the twelve most abundant PCB congeners found in serum from pregnant women at increased risk for having a child with an NDD. Using Golgi staining, the effect of developmental PCB exposure on dendritic arborization of pyramidal neurons in the CA1 hippocampus and somatosensory cortex of male and female WT mice was compared to pyramidal neurons from transgenic mice. A multilevel linear mixed-effects model identified a main effect of dose driven by increased dendritic arborization of cortical neurons in the 1 mg/kg PCB dose group. Subsequent analyses with genotypes indicated that the MARBLES PCB mixture had no effect on the dendritic arborization of hippocampal neurons in WT mice of either sex, but significantly increased dendritic arborization of cortical neurons of WT males in the 6 mg/kg PCB dose group. Transgene expression increased sensitivity to the impact of developmental PCB exposure on dendritic arborization in a sex-, and brain region-dependent manner. In conclusion, developmental exposure to PCBs present in the gestational environment of at-risk humans interfered with normal dendritic morphogenesis in the developing mouse brain in a sex-, genotype- and brain region-dependent manner. Overall, these observations provide proof-of-principle evidence that PCBs interact with heritable mutations to modulate a neurodevelopmental outcome of relevance to NDDs.
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Affiliation(s)
- Kimberly P Keil Stietz
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Carolyn R Klocke
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Tryssa E de Ruyter
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Machelle D Wilson
- Clinical and Translational Science Center, Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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7
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Sethi S, Keil Stietz KP, Valenzuela AE, Klocke CR, Silverman JL, Puschner B, Pessah IN, Lein PJ. Developmental Exposure to a Human-Relevant Polychlorinated Biphenyl Mixture Causes Behavioral Phenotypes That Vary by Sex and Genotype in Juvenile Mice Expressing Human Mutations That Modulate Neuronal Calcium. Front Neurosci 2021; 15:766826. [PMID: 34938155 PMCID: PMC8685320 DOI: 10.3389/fnins.2021.766826] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/17/2021] [Indexed: 01/13/2023] Open
Abstract
Polychlorinated biphenyls (PCBs) are putative environmental risks for neurodevelopmental disorders. Here, we tested two hypotheses: (1) developmental exposure to a human-relevant PCB mixture causes behavioral phenotypes relevant to neurodevelopmental disorders; and (2) expression of human mutations that dysregulate neuronal Ca2+ homeostasis influence sensitivity to behavioral effects of developmental PCB exposures. To test these hypotheses, we used mice that expressed a gain-of-function mutation (T4826I) in ryanodine receptor 1 (RYR1), the X-linked fragile X mental retardation 1 (FMR1) CGG repeat expansion or both mutations (double mutant; DM). Transgenic mice and wildtype (WT) mice were exposed to the MARBLES PCB mix at 0, 0.1, 1, and 6 mg/kg/day in the maternal diet throughout gestation and lactation. The MARBLES PCB mix simulates the relative proportions of the 12 most abundant PCB congeners found in the serum of pregnant women at increased risk for having a child with a neurodevelopmental disorder. We assessed ultrasonic vocalizations at postnatal day 7 (P7), spontaneous repetitive behaviors at P25-P30, and sociability at P27-P32. Developmental PCB exposure reduced ultrasonic vocalizations in WT litters in all dose groups, but had no effect on ultrasonic vocalizations in transgenic litters. Developmental PCB exposure significantly increased self-grooming and decreased sociability in WT males in the 0.1 mg/kg dose group, but had no effect on WT females in any dose group. Genotype alone influenced ultrasonic vocalizations, self-grooming and to a lesser extent sociability. Genotype alone also influenced effects of PCBs on sociability. PCB levels in the brain tissue of pups increased in a dose-dependent manner, but within any dose group did not differ between genotypes. In summary, developmental PCB exposure phenocopied social behavior phenotypes observed in mice expressing human mutations that modify intracellular Ca2+ dynamics, and expression of these mutations alleviated PCB effects on ultrasonic vocalizations and repetitive behavior, and modified the dose-response relationships and sex-dependent effects of PCB effects on social behavior. These findings suggest that: (1) developmental PCB exposure causes behavioral phenotypes that vary by sex and genotype; and (2) sex-specific responses to environmental factors may contribute to sex biases in the prevalence and/or severity of neurodevelopmental disorders.
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Affiliation(s)
- Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Kimberly P. Keil Stietz
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Anthony E. Valenzuela
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Carolyn R. Klocke
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Jill L. Silverman
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
- The MIND Institute, University of California, Davis, Davis, CA, United States
| | - Birgit Puschner
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Isaac N. Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- The MIND Institute, University of California, Davis, Davis, CA, United States
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- The MIND Institute, University of California, Davis, Davis, CA, United States
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8
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Brun NR, Panlilio JM, Zhang K, Zhao Y, Ivashkin E, Stegeman JJ, Goldstone JV. Developmental exposure to non-dioxin-like polychlorinated biphenyls promotes sensory deficits and disrupts dopaminergic and GABAergic signaling in zebrafish. Commun Biol 2021; 4:1129. [PMID: 34561524 PMCID: PMC8463681 DOI: 10.1038/s42003-021-02626-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/25/2021] [Indexed: 11/09/2022] Open
Abstract
The most abundant polychlorinated biphenyl (PCB) congeners found in the environment and in humans are neurotoxic. This is of particular concern for early life stages because the exposure of the more vulnerable developing nervous system to neurotoxic chemicals can result in neurobehavioral disorders. In this study, we uncover currently unknown links between PCB target mechanisms and neurobehavioral deficits using zebrafish as a vertebrate model. We investigated the effects of the abundant non-dioxin-like (NDL) congener PCB153 on neuronal morphology and synaptic transmission linked to the proper execution of a sensorimotor response. Zebrafish that were exposed during development to concentrations similar to those found in human cord blood and PCB contaminated sites showed a delay in startle response. Morphological and biochemical data demonstrate that even though PCB153-induced swelling of afferent sensory neurons, the disruption of dopaminergic and GABAergic signaling appears to contribute to PCB-induced motor deficits. A similar delay was observed for other NDL congeners but not for the potent dioxin-like congener PCB126. The effects on important and broadly conserved signaling mechanisms in vertebrates suggest that NDL PCBs may contribute to neurodevelopmental abnormalities in humans and increased selection pressures in vertebrate wildlife.
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Affiliation(s)
- Nadja R Brun
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Jennifer M Panlilio
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Kun Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Yanbin Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Evgeny Ivashkin
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA.,A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
| | - John J Stegeman
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Jared V Goldstone
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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9
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Latchney SE, Majewska AK. Persistent organic pollutants at the synapse: Shared phenotypes and converging mechanisms of developmental neurotoxicity. Dev Neurobiol 2021; 81:623-652. [PMID: 33851516 DOI: 10.1002/dneu.22825] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/27/2021] [Accepted: 04/09/2021] [Indexed: 12/18/2022]
Abstract
The developing nervous system is sensitive to environmental and physiological perturbations in part due to its protracted period of prenatal and postnatal development. Epidemiological and experimental studies link developmental exposures to persistent organic pollutants (POPs) including polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polybrominated diphenyl ethers, and benzo(a)pyrene to increased risk for neurodevelopmental disorders in children. Mechanistic studies reveal that many of the complex cellular processes that occur during sensitive periods of rapid brain development are cellular targets for developmental neurotoxicants. One area of research interest has focused on synapse formation and plasticity, processes that involve the growth and retraction of dendrites and dendritic spines. For each chemical discussed in this review, we summarize the morphological and electrophysiological data that provide evidence that developmental POP exposure produces long-lasting effects on dendritic morphology, spine formation, glutamatergic and GABAergic signaling systems, and synaptic transmission. We also discuss shared intracellular mechanisms, with a focus on calcium and thyroid hormone homeostasis, by which these chemicals act to modify synapses. We conclude our review highlighting research gaps that merit consideration when characterizing synaptic pathology elicited by chemical exposure. These gaps include low-dose and nonmonotonic dose-response effects, the temporal relationship between dendritic growth, spine formation, and synaptic activity, excitation-inhibition balance, hormonal effects, and the need for more studies in females to identify sex differences. By identifying converging pathological mechanisms elicited by POP exposure at the synapse, we can define future research directions that will advance our understanding of these chemicals on synapse structure and function.
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Affiliation(s)
- Sarah E Latchney
- Department of Biology, St. Mary's College of Maryland, St. Mary's City, MD, USA.,Department of Neuroscience, Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Ania K Majewska
- Department of Neuroscience, Del Monte Institute for Neuroscience, University of Rochester Medical Center, Rochester, NY, USA.,Center for Visual Science, University of Rochester Medical Center, Rochester, NY, USA
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10
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Richards LA, Schonhoff CM. Nitric oxide and sex differences in dendritic branching and arborization. J Neurosci Res 2021; 99:1390-1400. [PMID: 33538046 DOI: 10.1002/jnr.24789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/02/2021] [Indexed: 12/17/2022]
Abstract
Nitric oxide (NO) is an important signaling molecule with many functions in the nervous system. Derived from the enzymatic conversion of arginine by several nitric oxide synthases (NOS), NO plays significant roles in neuronal developmental events such as the establishment of dendritic branching or arbors. A brief summary of the discovery, molecular biology, and chemistry of NO, and a description of important NO-mediated signal transduction pathways with emphasis on the role for NO in the development of dendritic branching during neurodevelopment are presented. Important sex differences in neuronal nitric oxide synthase expression during neuronal development are considered. Finally, a survey of endogenous and exogenous substances that disrupt dendritic patterning is presented with particular emphasis on how these molecules may drive NO-mediated sex differences in dendritic branching.
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Affiliation(s)
- Laura A Richards
- Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, USA
| | - Christopher M Schonhoff
- Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, USA.,Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, USA
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11
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Keil Stietz KP, Kennedy CL, Sethi S, Valenzuela A, Nunez A, Wang K, Wang Z, Wang P, Spiegelhoff A, Puschner B, Bjorling DE, Lein PJ. In utero and lactational PCB exposure drives anatomic changes in the juvenile mouse bladder. Curr Res Toxicol 2021; 2:1-18. [PMID: 34337439 PMCID: PMC8317607 DOI: 10.1016/j.crtox.2021.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Bladder dysfunction, including incontinence, difficulty emptying the bladder, or urgency to urinate is a pervasive health and quality of life concern. However, risk factors for developing these symptoms are not completely understood, and the influence of exposure to environmental chemicals, especially during development, on the formation and function of the bladder is understudied. Environmental contaminants such as polychlorinated biphenyls (PCBs) are known to pose a risk to the developing brain; however, their influence on the development of peripheral target organs, such as bladder, are unknown. To address this data gap, C57Bl/6J mouse dams were exposed to an environmentally-relevant PCB mixture at 0, 0.1, 1 or 6 mg/kg daily beginning two weeks prior to mating and continuing through gestation and lactation. Bladders were collected from offspring at postnatal days (P) 28-31. PCB concentrations were detected in bladders in a dose-dependent manner. PCB effects on the bladder were sex- and dose-dependent. Overall, PCB effects were observed in male, but not female, bladders. PCBs increased bladder volume and suburothelial βIII-tubulin-positive nerve density compared to vehicle control. A subset of these nerves were sensory peptidergic axons indicated by increased calcitonin gene-related protein (CGRP) positive nerve fibers in mice exposed to the highest PCB dose compared to the lowest PCB dose. PCB-induced increased nerve density was also positively correlated with the number of mast cells in the bladder, suggesting inflammation may be involved. There were no detectable changes in epithelial composition or apoptosis as indicated by expression of cleaved caspase 3, suggesting PCBs do not cause overt toxicity. Bladder volume changes were not accompanied by changes in bladder mass or epithelial thickness, indicating that obstruction was not likely involved. Together, these results are the first to suggest that following developmental exposure, PCBs can distribute to the bladder and alter neuroanatomic development and bladder volume in male mice.
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Affiliation(s)
- Kimberly P. Keil Stietz
- Department of Molecular Biosciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, USA,Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA,Corresponding author at: Department of Comparative Biosciences University of Wisconsin-Madison School of Veterinary Medicine, 2015 Linden Drive, Madison, WI 53706, USA.
| | - Conner L. Kennedy
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, USA
| | - Anthony Valenzuela
- Department of Molecular Biosciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, USA
| | - Alexandra Nunez
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Kathy Wang
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Zunyi Wang
- Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Peiqing Wang
- Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Audrey Spiegelhoff
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Birgit Puschner
- Department of Molecular Biosciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, USA
| | - Dale E. Bjorling
- Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, USA
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12
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Sex-specific effects of developmental exposure to polychlorinated biphenyls on neuroimmune and dopaminergic endpoints in adolescent rats. Neurotoxicol Teratol 2020; 79:106880. [PMID: 32259577 DOI: 10.1016/j.ntt.2020.106880] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
Exposure to environmental contaminants early in life can have long lasting consequences for physiological function. Polychlorinated biphenyls (PCBs) are a group of ubiquitous contaminants that perturb endocrine signaling and have been associated with altered immune function in children. In this study, we examined the effects of developmental exposure to PCBs on neuroimmune responses to an inflammatory challenge during adolescence. Sprague Dawley rat dams were exposed to a PCB mixture (Aroclor 1242, 1248, 1254, 1:1:1, 20 μg/kg/day) or oil control throughout pregnancy, and adolescent male and female offspring were injected with lipopolysaccharide (LPS, 50 μg/kg, ip) or saline control prior to euthanasia. Gene expression profiling was conducted in the hypothalamus, prefrontal cortex, striatum, and midbrain. In the hypothalamus, PCBs increased expression of genes involved in neuroimmune function, including those within the nuclear factor kappa b (NF-κB) complex, independent of LPS challenge. PCB exposure also increased expression of receptors for dopamine, serotonin, and estrogen in this region. In contrast, in the prefrontal cortex, PCB exposure blunted or induced irregular neuroimmune gene expression responses to LPS challenge. Moreover, neither PCB nor LPS exposure altered expression of neurotransmitter receptors throughout the mesocorticolimbic circuit. Almost all effects were present in males but not females, in agreement with the idea that male neuroimmune cells are more sensitive to perturbation and emphasizing the importance of studying both male and female subjects. Given that altered neuroimmune signaling has been implicated in mental health and substance abuse disorders that often begin during adolescence, these results highlight neuroimmune processes as another mechanism by which early life PCBs can alter brain function later in life.
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Wlodarczyk-Li SA, Vassoler FM, Byrnes EM, Schonhoff CM. Oxycodone Decreases Dendritic Complexity in Female but not Male Rat Striatal Neurons In Vitro. Neurosci Lett 2020; 722:134856. [PMID: 32088199 DOI: 10.1016/j.neulet.2020.134856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 10/25/2022]
Abstract
The use of oxycodone in the past two decades has dramatically risen, yet the amount of research regarding how it impacts neuronal health is lacking. As prescription use and misuse in women of reproductive age increases there has been a corresponding increase in the number of infants who have been exposed to oxycodone in utero. Given the critical role of the striatum in motor control and reward regulation, the aim of the current study was to examine the effects of oxycodone on developing rat striatal neurons. Sex-specific effects of oxycodone on neuronal cytoarchitecture were examined in cultured rat striatal neurons with a primary focus on dendritic arborization. Neurons were extracted from either male or female embryonic day 18 rat striata and cultured and exposed to varying concentrations of oxycodone over a ten-day period. Dendritic complexity of the neurons was measured using Sholl analysis. Results indicate that oxycodone inhibits dendritic complexity in a dose-dependent manner in female but not male striatal neurons. Additional analysis indicated the number of non-primary dendrites in female striatal neurons significantly decreased with increasing concentrations of oxycodone, while the number of primary dendrites as well as the length of primary and non-primary dendrites was unaffected by oxycodone treatment in both sexes. These in vitro findings demonstrate sex-specific effects of oxycodone on the development of striatal dendritic architecture which may be important for understanding the effects of oxycodone exposure in utero.
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Affiliation(s)
- Sara A Wlodarczyk-Li
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, 01536, United States
| | - Fair M Vassoler
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, 01536, United States
| | - Elizabeth M Byrnes
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, 01536, United States
| | - Christopher M Schonhoff
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, 01536, United States.
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14
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Klocke C, Sethi S, Lein PJ. The developmental neurotoxicity of legacy vs. contemporary polychlorinated biphenyls (PCBs): similarities and differences. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8885-8896. [PMID: 31713823 PMCID: PMC7220795 DOI: 10.1007/s11356-019-06723-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 10/07/2019] [Indexed: 05/11/2023]
Abstract
Although banned from production for decades, PCBs remain a significant risk to human health. A primary target of concern is the developing brain. Epidemiological studies link PCB exposures in utero or during infancy to increased risk of neuropsychiatric deficits in children. Nonclinical studies of legacy congeners found in PCB mixtures synthesized prior to the ban on PCB production suggest that non-dioxin-like (NDL) congeners are predominantly responsible for the developmental neurotoxicity associated with PCB exposures. Mechanistic studies suggest that NDL PCBs alter neurodevelopment via ryanodine receptor-dependent effects on dendritic arborization. Lightly chlorinated congeners, which were not present in the industrial mixtures synthesized prior to the ban on PCB production, have emerged as contemporary environmental contaminants, but there is a paucity of data regarding their potential developmental neurotoxicity. PCB 11, a prevalent contemporary congener, is found in the serum of children and their mothers, as well as in the serum of pregnant women at increased risk for having a child diagnosed with a neurodevelopmental disorder (NDD). Recent data demonstrates that PCB 11 modulates neuronal morphogenesis via mechanisms that are convergent with and divergent from those implicated in the developmental neurotoxicity of legacy NDL PCBs. This review summarizes these data and discusses their relevance to adverse neurodevelopmental outcomes in humans.
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Affiliation(s)
- Carolyn Klocke
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Sunjay Sethi
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
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15
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Klocke C, Lein PJ. Evidence Implicating Non-Dioxin-Like Congeners as the Key Mediators of Polychlorinated Biphenyl (PCB) Developmental Neurotoxicity. Int J Mol Sci 2020; 21:E1013. [PMID: 32033061 PMCID: PMC7037228 DOI: 10.3390/ijms21031013] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 12/15/2022] Open
Abstract
Despite being banned from production for decades, polychlorinated biphenyls (PCBs) continue to pose a significant risk to human health. This is due to not only the continued release of legacy PCBs from PCB-containing equipment and materials manufactured prior to the ban on PCB production, but also the inadvertent production of PCBs as byproducts of contemporary pigment and dye production. Evidence from human and animal studies clearly identifies developmental neurotoxicity as a primary endpoint of concern associated with PCB exposures. However, the relative role(s) of specific PCB congeners in mediating the adverse effects of PCBs on the developing nervous system, and the mechanism(s) by which PCBs disrupt typical neurodevelopment remain outstanding questions. New questions are also emerging regarding the potential developmental neurotoxicity of lower chlorinated PCBs that were not present in the legacy commercial PCB mixtures, but constitute a significant proportion of contemporary human PCB exposures. Here, we review behavioral and mechanistic data obtained from experimental models as well as recent epidemiological studies that suggest the non-dioxin-like (NDL) PCBs are primarily responsible for the developmental neurotoxicity associated with PCBs. We also discuss emerging data demonstrating the potential for non-legacy, lower chlorinated PCBs to cause adverse neurodevelopmental outcomes. Molecular targets, the relevance of PCB interactions with these targets to neurodevelopmental disorders, and critical data gaps are addressed as well.
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Affiliation(s)
| | - Pamela J. Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA;
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16
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Rude KM, Keogh CE, Gareau MG. The role of the gut microbiome in mediating neurotoxic outcomes to PCB exposure. Neurotoxicology 2019; 75:30-40. [PMID: 31454514 DOI: 10.1016/j.neuro.2019.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/25/2019] [Accepted: 08/21/2019] [Indexed: 12/19/2022]
Abstract
A series of complex physiological processes underlie the development of the microbiota, gut, and brain in early life, which together communicate via the microbiota-gut-brain axis to maintain health and homeostasis. Disruption of these processes can lead to dysbiosis of the microbiota, pathophysiology of the gut and behavioral deficits including depression, anxiety and cognitive deficits. Environmental exposures, particularly in early life, can interfere with development and impact these pathways. This review will focus on the role of the microbiome and the gut in neurodevelopment and neurodegeneration as well as the impacts of environmental exposures, particularly to the neurotoxicant polychlorinated biphenyls (PCBs), given that the gut serves as the primary exposure route. There exists extensive research on the importance of the microbiome in the developing brain and connections with autism spectrum disorder (ASD) and increasing links being established between the microbiome and development of Alzheimer's disease (AD) in the elderly. Finally, we will speculate on the mechanisms through which PCBs can induce dysbiosis and dysregulate physiology of the gut and brain.
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Affiliation(s)
- Kavi M Rude
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - Ciara E Keogh
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - Mélanie G Gareau
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, United States.
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