Assessment of developmental neurotoxicology-associated alterations in neuronal architecture and function using Caenorhabditis elegans
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Abstract
Few of the many chemicals that regulatory agencies are charged with assessing for risk have been carefully tested for developmental neurotoxicity (DNT). To speed up assessment, and to reduce the use of vertebrate animals, great effort is being devoted to alternative laboratory models for DNT. A major DNT mechanism is altered neuronal architecture resulting from chemical exposure during neurodevelopment. Caenorhabditis elegans is a nematode that has been extensively studied by neurobiologists and developmental biologists, and to a lesser extent by neurotoxicologists. The development of the nervous system in C. elegans is easily visualized, entirely invariant, and fully mapped. We hypothesized that C. elegans could be a powerful in vivo model to test chemicals for their potential to alter neuronal architecture during development. We developed a novel C. elegans DNT testing paradigm that includes developmental exposure, examines major neurotransmitter neuronal types for architectural alterations, and tests neuron-specific behaviors. We characterized the effects of exposures to the developmental neurotoxicants lead, cadmium, and benzo(a)pyrene on neuronal architecture and specification. We identified no cases in which the apparent neurotransmitter type of the neurons we examined changed, but many in which neuronal morphology was altered. We found that neuron-specific behaviors were altered during C. elegans mid-adulthood for populations with measured morphological neurodegeneration in earlier stages. The functional changes were consistent with the morphological changes in terms of the type of neuron affected. Finally, we identified changes consistent with those reported in the mammalian DNT literature, strengthening the case for C. elegans as a DNT model.
Plain language summary
This study provides support and methods for the use of the nematode Caenorhabditis elegans to evaluate the effects of exposure to environmental pollutants on the developing nervous system, referred to as developmental neurotoxicity (DNT). Lead, cadmium, and benzo(a)pyrene, three chemicals known to cause DNT in animal models and linked to DNT in humans, were tested using improved protocols for exposure and assessment of morphological and functional changes. These experiments showed that chemical developmental exposure in nematodes led to various degrees of neurodegeneration by the time of their final larval stage, and subsequent behavioral changes and loss of resilience to additional chemical exposure during mid-adulthood. These results highlight the value of using C. elegans as an alternative model organism for DNT to reduce and replace animal experiments under the 3R framework.
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Ackley, B. D., Harrington, R. J., Hudson, M. L. et al. (2005). The two isoforms of the Caenorhabditis elegans leukocyte-common antigen related receptor tyrosine phosphatase PTP-3 function independently in axon guidance and synapse formation. J Neurosci 25, 7517–28. doi:10.1523/JNEUROSCI.2010-05.2005
Akinyemi, A. J., Miah, M. R., Ijomone, O. M. et al. (2019). Lead (Pb) exposure induces dopaminergic neurotoxicity in Caenorhabditis elegans: Involvement of the dopamine transporter. Toxicol Rep 6, 833–840. doi:10.1016/j.toxrep.2019.08.001
Albrecht, P. A., Fernandez-Hubeid, L. E., Deza-Ponzio, R. et al. (2022). Developmental lead exposure affects dopaminergic neuron morphology and modifies basal slowing response in Caenorhabditis elegans: Effects of ethanol. Neurotoxicology 91, 349–359. doi:10.1016/j.neuro.2022.06.005
Anderson, G. L., Boyd, W. A. and Williams, P. L. (2001). Assessment of sublethal endpoints for toxicity testing with the nematode Caenorhabditis elegans. Environ Toxicol Chem 20, 833–8. doi:10.1002/etc.5620200419
Antonio, M. T., Peinado, V., González, J. C. et al. (2010). Effects of maternal cadmium administration on development of monoaminergic, GABAergic and glutamatergic systems. Environ Toxicol Pharmacol 29, 87–90. doi:10.1016/j.etap.2009.11.003
Avery, L. and Shtonda, B. B. (2003). Food transport in the C. elegans pharynx. J Exp Biol 206, 2441–57. doi:10.1242/jeb.00433
Bal-Price, A. and Fritsche, E. (2018). Editorial: Developmental neurotoxicity. Toxicol Appl Pharmacol 354, 1–2. doi:10.1016/j.taap.2018.07.016
Barbosa, D. J., Capela, J. P., de Lourdes Bastos, M. et al. (2015). In vitro models for neurotoxicology research. Toxicol Res (Camb) 4, 801–842. doi:10.1039/C4TX00043A
Basha, D. C., Rani, M. U., Devi, C. B. et al. (2012). Perinatal lead exposure alters postnatal cholinergic and aminergic system in rat brain: reversal effect of calcium co-administration. Int J Dev Neurosci 30, 343–50. doi:10.1016/j.ijdevneu.2012.01.004
Bijwadia, S. R., Morton, K. and Meyer, J. N. (2021). Quantifying Levels of Dopaminergic Neuron Morphological Alteration and Degeneration in Caenorhabditis elegans. J Vis Exp. doi:10.3791/62894
Bishop, N. A. and Guarente, L. (2007). Two neurons mediate diet-restriction-induced longevity in C. elegans. Nature 447, 545–9. doi:10.1038/nature05904
Boyd, W. A., Smith, M. V, Kissling, G. E. et al. (2009). Application of a mathematical model to describe the effects of chlorpyrifos on Caenorhabditis elegans development. PLoS One 4, e7024. doi:10.1371/journal.pone.0007024
Boyd, W. A., Smith, M. V., Kissling, G. E. et al. (2010). Medium- and high-throughput screening of neurotoxicants using C. elegans. Neurotoxicol Teratol 32, 68–73. doi:10.1016/J.NTT.2008.12.004
Braak, H., Rüb, U., Gai, W. P. et al. (2003). Idiopathic Parkinson’s disease: possible routes by which vulnerable neuronal types may be subject to neuroinvasion by an unknown pathogen. J Neural Transm (Vienna) 110, 517–36. doi:10.1007/s00702-002-0808-2
Breier, J. M., Gassmann, K., Kayser, R. et al. (2010). Neural progenitor cells as models for high-throughput screens of developmental neurotoxicity: state of the science. Neurotoxicol Teratol 32, 4–15. doi:10.1016/j.ntt.2009.06.005
Brown, L. A., Khousbouei, H., Goodwin, J. S. et al. (2007). Down-regulation of early ionotrophic glutamate receptor subunit developmental expression as a mechanism for observed plasticity deficits following gestational exposure to benzo(a)pyrene. Neurotoxicology 28, 965–78. doi:10.1016/j.neuro.2007.05.005
Caldwell, K. A., Willicott, C. W. and Caldwell, G. A. (2020). Modeling neurodegeneration in Caenorhabditis elegans. Dis Model Mech 13. doi:10.1242/dmm.046110
Chalfie, M. and Sulston, J. (1981). Developmental genetics of the mechanosensory neurons of Caenorhabditis elegans. Dev Biol 82, 358–70. doi:10.1016/0012-1606(81)90459-0
Chandravanshi, L., Shiv, K. and Kumar, S. (2021). Developmental toxicity of cadmium in infants and children: a review. Environ Anal Health Toxicol 36, e2021003-0. doi:10.5620/eaht.2021003
Chase, D. L., Pepper, J. S. and Koelle, M. R. (2004). Mechanism of extrasynaptic dopamine signaling in Caenorhabditis elegans. Nat Neurosci 7, 1096–103. doi:10.1038/nn1316
Chatterjee, N., González-Durruthy, M., Costa, M. D. et al. (2024). Differential impact of diesel exhaust particles on glutamatergic and dopaminergic neurons in Caenorhabditis elegans: A neurodegenerative perspective. Environ Int 186, 108597. doi:10.1016/j.envint.2024.108597
Chepelev, N. L., Moffat, I. D., Bowers, W. J. et al. (2015). Neurotoxicity may be an overlooked consequence of benzo[a]pyrene exposure that is relevant to human health risk assessment. Mutat Res Rev Mutat Res 764, 64–89. doi:10.1016/j.mrrev.2015.03.001
Chikka, M. R., Anbalagan, C., Dvorak, K. et al. (2016). The Mitochondria-Regulated Immune Pathway Activated in the C. elegans Intestine Is Neuroprotective. Cell Rep 16, 2399–414. doi:10.1016/j.celrep.2016.07.077
Chow, E. S. H., Hui, M. N. Y., Lin, C. C. et al. (2008). Cadmium inhibits neurogenesis in zebrafish embryonic brain development. Aquat Toxicol 87, 157–69. doi:10.1016/j.aquatox.2008.01.019
Clark, A. S., Huayta, J., Morton, K. S. et al. (2024). Morphological hallmarks of dopaminergic neurodegeneration are associated with altered neuron function in Caenorhabditis elegans. Neurotoxicology 100, 100–106. doi:10.1016/j.neuro.2023.12.005
Clement, J. G. and Colhoun, E. H. (1975a). Inhibition of choline transport into human erythrocytes by choline mustard aziridinium ion. Can J Physiol Pharmacol 53, 1089–93. doi:10.1139/y75-151
Clement, J. G. and Colhoun, E. H. (1975b). Presynaptic effect of the aziridinium ion of acetylcholine mustard (methyl-2-acetoxyethyl-2’-chloroethylamine) on the phrenic nerve--rat diaphragm preparation. Can J Physiol Pharmacol 53, 264–72. doi:10.1139/y75-038
Coecke, S., Goldberg, A. M., Allen, S. et al. (2007). Workgroup report: incorporating in vitro alternative methods for developmental neurotoxicity into international hazard and risk assessment strategies. Environ Health Perspect 115, 924–31. doi:10.1289/ehp.9427
Di Consiglio, E., Pistollato, F., Mendoza-De Gyves, E. et al. (2020). Integrating biokinetics and in vitro studies to evaluate developmental neurotoxicity induced by chlorpyrifos in human iPSC-derived neural stem cells undergoing differentiation towards neuronal and glial cells. Reprod Toxicol 98, 174–188. doi:10.1016/j.reprotox.2020.09.010
Crofton, K. M., Mundy, W. R. and Shafer, T. J. (2012). Developmental neurotoxicity testing: a path forward. Congenit Anom (Kyoto) 52, 140–6. doi:10.1111/j.1741-4520.2012.00377.x
Dam, K., Garcia, S. J., Seidler, F. J. et al. (1999). Neonatal chlorpyrifos exposure alters synaptic development and neuronal activity in cholinergic and catecholaminergic pathways. Brain Res Dev Brain Res 116, 9–20. doi:10.1016/s0165-3806(99)00067-x
Devi, C. B., Reddy, G. H., Prasanthi, R. P. J. et al. (2005). Developmental lead exposure alters mitochondrial monoamine oxidase and synaptosomal catecholamine levels in rat brain. Int J Dev Neurosci 23, 375–81. doi:10.1016/j.ijdevneu.2004.11.003
Edwards, S. E., Maxson, P., Miranda, M. L. et al. (2015). Cadmium levels in a North Carolina cohort: Identifying risk factors for elevated levels during pregnancy. J Expo Sci Environ Epidemiol 25, 427–32. doi:10.1038/jes.2014.53
EPA (1998). Guidelines for Neurotoxicity Risk Assessment. https://www.epa.gov/sites/default/files/2014-11/documents/neuro_tox.pdf
Erikson, K. M. and Aschner, M. (2003). Manganese neurotoxicity and glutamate-GABA interaction. Neurochem Int 43, 475–80. doi:10.1016/s0197-0186(03)00037-8
Etchberger, J. F., Lorch, A., Sleumer, M. C. et al. (2007). The molecular signature and cis-regulatory architecture of a C. elegans gustatory neuron. Genes Dev 21, 1653–74. doi:10.1101/gad.1560107
Fisher, A., Mantione, C. R., Abraham, D. J. et al. (1982). Long-term central cholinergic hypofunction induced in mice by ethylcholine aziridinium ion (AF64A) in vivo. J Pharmacol Exp Ther 222, 140–5.
Fritsche, E., Grandjean, P., Crofton, K. M. et al. (2018). Consensus statement on the need for innovation, transition and implementation of developmental neurotoxicity (DNT) testing for regulatory purposes. Toxicol Appl Pharmacol 354, 3–6. doi:10.1016/j.taap.2018.02.004
Gao, D., Wang, C., Xi, Z. et al. (2017). Early-Life Benzo[a]Pyrene Exposure Causes Neurodegenerative Syndromes in Adult Zebrafish (Danio rerio) and the Mechanism Involved. Toxicol Sci 157, 74–84. doi:10.1093/toxsci/kfx028
Gao, S. and Zhen, M. (2011). Action potentials drive body wall muscle contractions in Caenorhabditis elegans. Proc Natl Acad Sci U S A 108, 2557–62. doi:10.1073/pnas.1012346108
Gao, X., Wang, Y., Song, Z. et al. (2024). Early-life risk factors, accelerated biological aging and the late-life risk of mortality and morbidity. QJM 117, 257–268. doi:10.1093/qjmed/hcad247
Gibson, C. L., Balbona, J. T., Niedzwiecki, A. et al. (2018). Glial loss of the metallo β-lactamase domain containing protein, SWIP-10, induces age- and glutamate-signaling dependent, dopamine neuron degeneration. PLoS Genet 14, e1007269. doi:10.1371/journal.pgen.1007269
Gillis, B. S., Arbieva, Z. and Gavin, I. M. (2012). Analysis of lead toxicity in human cells. BMC Genomics 13, 344. doi:10.1186/1471-2164-13-344
Goodman, M. B., Ernstrom, G. G., Chelur, D. S. et al. (2002). MEC-2 regulates C. elegans DEG/ENaC channels needed for mechanosensation. Nature 415, 1039–42. doi:10.1038/4151039a
Goodman, M. B., Hall, D. H., Avery, L. et al. (1998). Active currents regulate sensitivity and dynamic range in C. elegans neurons. Neuron 20, 763–72. doi:10.1016/s0896-6273(00)81014-4
Goodman, M. B. and Sengupta, P. (2019). How Caenorhabditis elegans Senses Mechanical Stress, Temperature, and Other Physical Stimuli. Genetics 212, 25–51. doi:10.1534/genetics.118.300241
Gracheva, E. O., Burdina, A. O., Holgado, A. M. et al. (2006). Tomosyn inhibits synaptic vesicle priming in Caenorhabditis elegans. PLoS Biol 4, e261. doi:10.1371/journal.pbio.0040261
Griffin, E. F., Scopel, S. E., Stephen, C. A. et al. (2019). ApoE-associated modulation of neuroprotection from Aβ-mediated neurodegeneration in transgenic Caenorhabditis elegans. Dis Model Mech 12. doi:10.1242/dmm.037218
Guo, J. and Wen, X. (2021). Performance and kinetics of benzo(a)pyrene biodegradation in contaminated water and soil and improvement of soil properties by biosurfactant amendment. Ecotoxicol Environ Saf 207, 111292. doi:10.1016/j.ecoenv.2020.111292
Guo, Y., Yang, Y. and Wang, D. (2009). Induction of reproductive deficits in nematode Caenorhabditis elegans exposed to metals at different developmental stages. Reprod Toxicol 28, 90–5. doi:10.1016/j.reprotox.2009.03.007
Gustafsson, J. P. (2020). Visual MINTEQ version 3.1. https://vminteq.com/
Gutiérrez-Reyes, E. Y., Albores, A. and Ríos, C. (1998). Increase of striatal dopamine release by cadmium in nursing rats and its prevention by dexamethasone-induced metallothionein. Toxicology 131, 145–54. doi:10.1016/s0300-483x(98)00126-7
Han, S. K., Lee, D., Lee, H. et al. (2016). OASIS 2: online application for survival analysis 2 with features for the analysis of maximal lifespan and healthspan in aging research. Oncotarget 7, 56147–56152. doi:10.18632/oncotarget.11269
Harris, J. B., Hartman, J. H., Luz, A. L. et al. (2020). Zebrafish CYP1A expression in transgenic Caenorhabditis elegans protects from exposures to benzo[a]pyrene and a complex polycyclic aromatic hydrocarbon mixture. Toxicology 440, 152473. doi:10.1016/j.tox.2020.152473
Hartman, J. H., Widmayer, S. J., Bergemann, C. M. et al. (2021). Xenobiotic metabolism and transport in Caenorhabditis elegans. J Toxicol Environ Health B Crit Rev 24, 51–94. doi:10.1080/10937404.2021.1884921
He, C., Wang, C., Zhou, Y. et al. (2012). Embryonic exposure to benzo(a)pyrene influences neural development and function in rockfish (Sebastiscus marmoratus). Neurotoxicology 33, 758–62. doi:10.1016/j.neuro.2012.01.002
Hobert, O. (2010). Neurogenesis in the nematode Caenorhabditis elegans. WormBook, 1–24. doi:10.1895/wormbook.1.12.2
Hockley, S. L., Arlt, V. M., Brewer, D. et al. (2006). Time- and concentration-dependent changes in gene expression induced by benzo(a)pyrene in two human cell lines, MCF-7 and HepG2. BMC Genomics 7, 260. doi:10.1186/1471-2164-7-260
Huang, X., Powell-Coffman, J. A. and Jin, Y. (2004). The AHR-1 aryl hydrocarbon receptor and its co-factor the AHA-1 aryl hydrocarbon receptor nuclear translocator specify GABAergic neuron cell fate in C. elegans. Development 131, 819–28. doi:10.1242/dev.00959
Hunt, P. R. (2017). The C. elegans model in toxicity testing. J Appl Toxicol 37, 50–59. doi:10.1002/jat.3357
Hunt, P. R., Olejnik, N., Bailey, K. D. et al. (2018). C. elegans Development and Activity Test detects mammalian developmental neurotoxins. Food Chem Toxicol 121, 583–592. doi:10.1016/j.fct.2018.09.061
Ijomone, O. M., Miah, M. R., Akingbade, G. T. et al. (2020). Nickel-Induced Developmental Neurotoxicity in C. elegans Includes Cholinergic, Dopaminergic and GABAergic Degeneration, Altered Behaviour, and Increased SKN-1 Activity. Neurotox Res 37, 1018–1028. doi:10.1007/s12640-020-00175-3
Karengera, A., Sterken, M. G., Kammenga, J. E. et al. (2022). Differential expression of genes in C. elegans reveals transcriptional responses to indirect-acting xenobiotic compounds and insensitivity to 2,3,7,8-tetrachlorodibenzodioxin. Ecotoxicol Environ Saf 233, 113344. doi:10.1016/j.ecoenv.2022.113344
Kelly, S. L. and Kelly, D. E. (2013). Microbial cytochromes P450: biodiversity and biotechnology. Where do cytochromes P450 come from, what do they do and what can they do for us? Philos Trans R Soc Lond B Biol Sci 368, 20120476. doi:10.1098/rstb.2012.0476
King, K. E., Darrah, T. H., Money, E. et al. (2015). Geographic clustering of elevated blood heavy metal levels in pregnant women. BMC Public Health 15, 1035. doi:10.1186/s12889-015-2379-9
Klingelhoefer, L. and Reichmann, H. (2015). Pathogenesis of Parkinson disease--the gut-brain axis and environmental factors. Nat Rev Neurol 11, 625–36. doi:10.1038/nrneurol.2015.197
Koushika, S. P., Richmond, J. E., Hadwiger, G. et al. (2001). A post-docking role for active zone protein Rim. Nat Neurosci 4, 997–1005. doi:10.1038/nn732
Lafuente, A., González-Carracedo, A., Romero, A. et al. (2005). Toxic effects of cadmium on the regulatory mechanism of dopamine and serotonin on prolactin secretion in adult male rats. Toxicol Lett 155, 87–96. doi:10.1016/j.toxlet.2004.08.011
Laranjeiro, R., Harinath, G., Hewitt, J. E. et al. (2019). Swim exercise in Caenorhabditis elegans extends neuromuscular and gut healthspan, enhances learning ability, and protects against neurodegeneration. Proc Natl Acad Sci U S A 116, 23829–23839. doi:10.1073/pnas.1909210116
Leal, R. B., Rieger, D. K., Peres, T. V. et al. (2012). Cadmium Neurotoxicity and Its Role in Brain Disorders. In Metal Ion in Stroke (751–766). New York, NY: Springer New York. doi:10.1007/978-1-4419-9663-3_34
Lee, R. Y., Sawin, E. R., Chalfie, M. et al. (1999). EAT-4, a homolog of a mammalian sodium-dependent inorganic phosphate cotransporter, is necessary for glutamatergic neurotransmission in caenorhabditis elegans. J Neurosci 19, 159–67. doi:10.1523/JNEUROSCI.19-01-00159.1999
Lein, P., Locke, P. and Goldberg, A. (2007). Meeting report: alternatives for developmental neurotoxicity testing. Environ Health Perspect 115, 764–8. doi:10.1289/ehp.9841
Leung, M. C. K., Goldstone, J. V, Boyd, W. A. et al. (2010). Caenorhabditis elegans generates biologically relevant levels of genotoxic metabolites from aflatoxin B1 but not benzo[a]pyrene in vivo. Toxicol Sci 118, 444–53. doi:10.1093/toxsci/kfq295
Leung, M. C. K., Williams, P. L., Benedetto, A. et al. (2008). Caenorhabditis elegans: an emerging model in biomedical and environmental toxicology. Toxicol Sci 106, 5–28. doi:10.1093/toxsci/kfn121
Leuthner, T. C., Benzing, L., Kohrn, B. F. et al. (2022). Resistance of mitochondrial DNA to cadmium and Aflatoxin B1 damage-induced germline mutation accumulation in C. elegans. Nucleic Acids Res 50, 8626–8642. doi:10.1093/nar/gkac666
Li, A. A., Sheets, L. P., Raffaele, K. et al. (2017). Recommendations for harmonization of data collection and analysis of developmental neurotoxicity endpoints in regulatory guideline studies: Proceedings of workshops presented at Society of Toxicology and joint Teratology Society and Neurobehavioral Teratology Society meetings. Neurotoxicol Teratol 63, 24–45. doi:10.1016/j.ntt.2017.07.001
Lin, C.-C., Chen, Y.-C., Su, F.-C. et al. (2013). In utero exposure to environmental lead and manganese and neurodevelopment at 2 years of age. Environ Res 123, 52–7. doi:10.1016/j.envres.2013.03.003
Liu, Q., Kidd, P. B., Dobosiewicz, M. et al. (2018). C. elegans AWA Olfactory Neurons Fire Calcium-Mediated All-or-None Action Potentials. Cell 175, 57-70.e17. doi:10.1016/j.cell.2018.08.018
Llorens, F., Gil, V. and del Río, J. A. (2011). Emerging functions of myelin-associated proteins during development, neuronal plasticity, and neurodegeneration. FASEB J 25, 463–75. doi:10.1096/fj.10-162792
Lu, C., Svoboda, K. R., Lenz, K. A. et al. (2018). Toxicity interactions between manganese (Mn) and lead (Pb) or cadmium (Cd) in a model organism the nematode C. elegans. Environ Sci Pollut Res Int 25, 15378–15389. doi:10.1007/s11356-018-1752-5
Ma, T., Chen, H. H. and Ho, I. K. (1999). Effects of chronic lead (Pb) exposure on neurobehavioral function and dopaminergic neurotransmitter receptors in rats. Toxicol Lett 105, 111–21. doi:10.1016/s0378-4274(98)00388-9
Mahoney, T. R., Luo, S. and Nonet, M. L. (2006). Analysis of synaptic transmission in Caenorhabditis elegans using an aldicarb-sensitivity assay. Nat Protoc 1, 1772–7. doi:10.1038/nprot.2006.281
Martinez, N. J., Ow, M. C., Reece-Hoyes, J. S. et al. (2008). Genome-scale spatiotemporal analysis of Caenorhabditis elegans microRNA promoter activity. Genome Res 18, 2005–15. doi:10.1101/gr.083055.108
Maurer, L. L., Luz, A. L. and Meyer, J. N. (2018). Detection of Mitochondrial Toxicity of Environmental Pollutants Using Caenorhabditis elegans. In Mitochondrial Dysfunction Caused by Drugs and Environmental Toxicants (655–689). Wiley. doi:10.1002/9781119329725.ch43
Maurer, L. L., Ryde, I. T., Yang, X. et al. (2015). Caenorhabditis elegans as a Model for Toxic Effects of Nanoparticles: Lethality, Growth, and Reproduction. Curr Protoc Toxicol 66, 20.10.1-20.10.25. doi:10.1002/0471140856.tx2010s66
McCallister, M. M., Maguire, M., Ramesh, A. et al. (2008). Prenatal exposure to benzo(a)pyrene impairs later-life cortical neuronal function. Neurotoxicology 29, 846–54. doi:10.1016/j.neuro.2008.07.008
McKelvey, W., Gwynn, R. C., Jeffery, N. et al. (2007). A biomonitoring study of lead, cadmium, and mercury in the blood of New York city adults. Environ Health Perspect 115, 1435–41. doi:10.1289/ehp.10056
Meier, M. J., O’Brien, J. M., Beal, M. A. et al. (2017). In Utero Exposure to Benzo[a]Pyrene Increases Mutation Burden in the Soma and Sperm of Adult Mice. Environ Health Perspect 125, 82–88. doi:10.1289/EHP211
Meyer, D. and Williams, P. L. (2014). Toxicity testing of neurotoxic pesticides in Caenorhabditis elegans. J Toxicol Environ Health B Crit Rev 17, 284–306. doi:10.1080/10937404.2014.933722
Meyer, J. N., Lord, C. A., Yang, X. Y. et al. (2010). Intracellular uptake and associated toxicity of silver nanoparticles in Caenorhabditis elegans. Aquat Toxicol 100, 140–50. doi:10.1016/j.aquatox.2010.07.016
Miller, D. B. and O’Callaghan, J. P. (2008). Do early-life insults contribute to the late-life development of Parkinson and Alzheimer diseases? Metabolism 57 Suppl 2, S44-9. doi:10.1016/j.metabol.2008.07.011
Miller, G. W., Chandrasekaran, V., Yaghoobi, B. et al. (2018). Opportunities and challenges for using the zebrafish to study neuronal connectivity as an endpoint of developmental neurotoxicity. Neurotoxicology 67, 102–111. doi:10.1016/j.neuro.2018.04.016
Moné, M. J., Pallocca, G., Escher, S. E. et al. (2020). Setting the stage for next-generation risk assessment with non-animal approaches: the EU-ToxRisk project experience. Arch Toxicol 94, 3581–3592. doi:10.1007/s00204-020-02866-4
Moore, B. T., Jordan, J. M. and Baugh, L. R. (2013). WormSizer: high-throughput analysis of nematode size and shape. PLoS One 8, e57142. doi:10.1371/journal.pone.0057142
Mundy, W. R., Padilla, S., Breier, J. M. et al. (2015). Expanding the test set: Chemicals with potential to disrupt mammalian brain development. Neurotoxicol Teratol 52, 25–35. doi:10.1016/j.ntt.2015.10.001
Nass, R., Hall, D. H., Miller, D. M. et al. (2002). Neurotoxin-induced degeneration of dopamine neurons in Caenorhabditis elegans. Proc Natl Acad Sci U S A 99, 3264–9. doi:10.1073/pnas.042497999
Naudin, L., Jiménez Laredo, J. L., Liu, Q. et al. (2022). Systematic generation of biophysically detailed models with generalization capability for non-spiking neurons. PLoS One 17, e0268380. doi:10.1371/journal.pone.0268380
Neal, A. P. and Guilarte, T. R. (2013). Mechanisms of lead and manganese neurotoxicity. Toxicol Res (Camb) 2, 99–114. doi:10.1039/C2TX20064C
Oikonomou, G. and Shaham, S. (2011). The glia of Caenorhabditis elegans. Glia 59, 1253–63. doi:10.1002/glia.21084
Olabarrieta, I., L’Azou, B., Yuric, S. et al. (2001). In vitro effects of cadmium on two different animal cell models. Toxicol In Vitro 15, 511–7. doi:10.1016/s0887-2333(01)00056-x
Omura, D. T., Clark, D. A., Samuel, A. D. T. et al. (2012). Dopamine signaling is essential for precise rates of locomotion by C. elegans. PLoS One 7, e38649. doi:10.1371/journal.pone.0038649
Opperman, C. H. and Chang, S. (1991). Effects of Aldicarb and Fenamiphos on Acetycholinesterase and Motility of Caenorhabditis elegans. J Nematol 23, 20–7.
Ortiz, L., Nakamura, B., Li, X. et al. (2013). In utero exposure to benzo[a]pyrene increases adiposity and causes hepatic steatosis in female mice, and glutathione deficiency is protective. Toxicol Lett 223, 260–7. doi:10.1016/j.toxlet.2013.09.017
Peterson, R. T., Nass, R., Boyd, W. A. et al. (2008). Use of non-mammalian alternative models for neurotoxicological study. Neurotoxicology 29, 546–55. doi:10.1016/j.neuro.2008.04.006
Poole, R. J., Flames, N. and Cochella, L. (2024). Neurogenesis in Caenorhabditis elegans. M. Sundaram (ed.),. Genetics 228. doi:10.1093/genetics/iyae116
Powell-Coffman, J. A., Bradfield, C. A. and Wood, W. B. (1998). Caenorhabditis elegans orthologs of the aryl hydrocarbon receptor and its heterodimerization partner the aryl hydrocarbon receptor nuclear translocator. Proc Natl Acad Sci U S A 95, 2844–9. doi:10.1073/pnas.95.6.2844
Prahlad, V., Cornelius, T. and Morimoto, R. I. (2008). Regulation of the cellular heat shock response in Caenorhabditis elegans by thermosensory neurons. Science 320, 811–4. doi:10.1126/science.1156093
Raffaele, K. C., Rowland, J., May, B. et al. (2010). The use of developmental neurotoxicity data in pesticide risk assessments. Neurotoxicol Teratol 32, 563–72. doi:10.1016/j.ntt.2010.04.053
Rai, A., Maurya, S. K., Khare, P. et al. (2010). Characterization of developmental neurotoxicity of As, Cd, and Pb mixture: synergistic action of metal mixture in glial and neuronal functions. Toxicol Sci 118, 586–601. doi:10.1093/toxsci/kfq266
Reddy, G. R., Devi, B. C. and Chetty, C. S. (2007). Developmental lead neurotoxicity: alterations in brain cholinergic system. Neurotoxicology 28, 402–7. doi:10.1016/j.neuro.2006.03.018
Romussi, S., Giunti, S., Andersen, N. et al. (2024). C. elegans: a prominent platform for modeling and drug screening in neurological disorders. Expert Opin Drug Discov 19, 565–585. doi:10.1080/17460441.2024.2329103
Ruszkiewicz, J. A., Pinkas, A., Miah, M. R. et al. (2018). C. elegans as a model in developmental neurotoxicology. Toxicol Appl Pharmacol 354, 126–135. doi:10.1016/j.taap.2018.03.016
Sachana, M., Bal-Price, A., Crofton, K. M. et al. (2019). International Regulatory and Scientific Effort for Improved Developmental Neurotoxicity Testing. Toxicol Sci 167, 45–57. doi:10.1093/toxsci/kfy211
Sammi, S. R., Agim, Z. S. and Cannon, J. R. (2018). From the Cover: Harmane-Induced Selective Dopaminergic Neurotoxicity in Caenorhabditis elegans. Toxicol Sci 161, 335–348. doi:10.1093/toxsci/kfx223
Sawin, E. R., Ranganathan, R. and Horvitz, H. R. (2000). C. elegans locomotory rate is modulated by the environment through a dopaminergic pathway and by experience through a serotonergic pathway. Neuron 26, 619–31. doi:10.1016/s0896-6273(00)81199-x
Schafer, W. (2016). Nematode nervous systems. Curr Biol 26, R955–R959. doi:10.1016/j.cub.2016.07.044
da Silveira, T. L., Zamberlan, D. C., Arantes, L. P. et al. (2018). Quinolinic acid and glutamatergic neurodegeneration in Caenorhabditis elegans. Neurotoxicology 67, 94–101. doi:10.1016/j.neuro.2018.04.015
Singhvi, A. and Shaham, S. (2019). Glia-Neuron Interactions in Caenorhabditis elegans. Annu Rev Neurosci 42, 149–168. doi:10.1146/annurev-neuro-070918-050314
Slotkin, T. A., Card, J. and Seidler, F. J. (2013). Adverse benzo[a]pyrene effects on neurodifferentiation are altered by other neurotoxicant coexposures: interactions with dexamethasone, chlorpyrifos, or nicotine in PC12 cells. Environ Health Perspect 121, 825–31. doi:10.1289/ehp.1306528
Slotkin, T. A., Cousins, M. M., Tate, C. A. et al. (2001). Persistent cholinergic presynaptic deficits after neonatal chlorpyrifos exposure. Brain Res 902, 229–43. doi:10.1016/s0006-8993(01)02387-3
Slotkin, T. A., Levin, E. D. and Seidler, F. J. (2009). Developmental neurotoxicity of parathion: progressive effects on serotonergic systems in adolescence and adulthood. Neurotoxicol Teratol 31, 11–7. doi:10.1016/j.ntt.2008.08.004
Slotkin, T. A., Ryde, I. T., Levin, E. D. et al. (2008). Developmental neurotoxicity of low dose diazinon exposure of neonatal rats: effects on serotonin systems in adolescence and adulthood. Brain Res Bull 75, 640–7. doi:10.1016/j.brainresbull.2007.10.008
Slotkin, T. A., Skavicus, S., Card, J. et al. (2016). Diverse neurotoxicants target the differentiation of embryonic neural stem cells into neuronal and glial phenotypes. Toxicology 372, 42–51. doi:10.1016/j.tox.2016.10.015
Slotkin, T. A., Skavicus, S., Card, J. et al. (2017). In vitro models reveal differences in the developmental neurotoxicity of an environmental polycylic aromatic hydrocarbon mixture compared to benzo[a]pyrene: Neuronotypic PC12 Cells and embryonic neural stem cells. Toxicology 377, 49–56. doi:10.1016/j.tox.2016.12.008
Slotkin, T. A., Skavicus, S., Ko, A. et al. (2019). The Developmental Neurotoxicity of Tobacco Smoke Can Be Mimicked by a Combination of Nicotine and Benzo[a]Pyrene: Effects on Cholinergic and Serotonergic Systems. Toxicol Sci 167, 293–304. doi:10.1093/toxsci/kfy241
Spann, N., Goedkoop, W. and Traunspurger, W. (2015). Phenanthrene bioaccumulation in the nematode Caenorhabditis elegans. Environ Sci Technol 49, 1842–50. doi:10.1021/es504553t
Stansfield, K. H., Ruby, K. N., Soares, B. D. et al. (2015). Early-life lead exposure recapitulates the selective loss of parvalbumin-positive GABAergic interneurons and subcortical dopamine system hyperactivity present in schizophrenia. Transl Psychiatry 5, e522. doi:10.1038/tp.2014.147
Stiernagle, T. (2006). Maintenance of C. elegans. WormBook, 1–11. doi:10.1895/wormbook.1.101.1
Struzyńska, L. (2009). A glutamatergic component of lead toxicity in adult brain: the role of astrocytic glutamate transporters. Neurochem Int 55, 151–6. doi:10.1016/j.neuint.2009.01.025
Sulston, J. E. and Horvitz, H. R. (1977). Post-embryonic cell lineages of the nematode, Caenorhabditis elegans. Dev Biol 56, 110–56. doi:10.1016/0012-1606(77)90158-0
Sulston, J. E., Schierenberg, E., White, J. G. et al. (1983). The embryonic cell lineage of the nematode Caenorhabditis elegans. Dev Biol 100, 64–119. doi:10.1016/0012-1606(83)90201-4
Sun, H. and Hobert, O. (2023). Temporal transitions in the postembryonic nervous system of the nematode Caenorhabditis elegans: Recent insights and open questions. Semin Cell Dev Biol 142, 67–80. doi:10.1016/j.semcdb.2022.05.029
Suzuki, H., Kerr, R., Bianchi, L. et al. (2003). In vivo imaging of C. elegans mechanosensory neurons demonstrates a specific role for the MEC-4 channel in the process of gentle touch sensation. Neuron 39, 1005–17. doi:10.1016/j.neuron.2003.08.015
Szczerbak, G., Nowak, P., Kostrzewa, R. M. et al. (2007). Maternal lead exposure produces long-term enhancement of dopaminergic reactivity in rat offspring. Neurochem Res 32, 1791–8. doi:10.1007/s11064-007-9306-0
Sze, J. Y., Victor, M., Loer, C. et al. (2000). Food and metabolic signalling defects in a Caenorhabditis elegans serotonin-synthesis mutant. Nature 403, 560–4. doi:10.1038/35000609
Tamm, C. and Ceccatelli, S. (2017). Mechanistic insight into neurotoxicity induced by developmental insults. Biochem Biophys Res Commun 482, 408–418. doi:10.1016/j.bbrc.2016.10.087
Tang, B., Tong, P., Xue, K. S. et al. (2019). High-throughput assessment of toxic effects of metal mixtures of cadmium(Cd), lead(Pb), and manganese(Mn) in nematode Caenorhabditis elegans. Chemosphere 234, 232–241. doi:10.1016/j.chemosphere.2019.05.271
Tatum, M. C., Ooi, F. K., Chikka, M. R. et al. (2015). Neuronal serotonin release triggers the heat shock response in C. elegans in the absence of temperature increase. Curr Biol 25, 163–174. doi:10.1016/j.cub.2014.11.040
Taylor, S. R., Santpere, G., Weinreb, A. et al. (2021). Molecular topography of an entire nervous system. Cell 184, 4329-4347.e23. doi:10.1016/j.cell.2021.06.023
Tejeda-Benitez, L. and Olivero-Verbel, J. (2016). Caenorhabditis elegans, a Biological Model for Research in Toxicology. Rev Environ Contam Toxicol 237, 1–35. doi:10.1007/978-3-319-23573-8_1
Tyson, T., Senchuk, M., Cooper, J. F. et al. (2017). Novel animal model defines genetic contributions for neuron-to-neuron transfer of α-synuclein. Sci Rep 7, 7506. doi:10.1038/s41598-017-07383-6
Vellingiri, B., Suriyanarayanan, A., Selvaraj, P. et al. (2022). Role of heavy metals (copper (Cu), arsenic (As), cadmium (Cd), iron (Fe) and lithium (Li)) induced neurotoxicity. Chemosphere 301, 134625. doi:10.1016/j.chemosphere.2022.134625
Vermillion Maier, M. L., Siddens, L. K., Pennington, J. M. et al. (2022). Benzo[a]pyrene (BaP) metabolites predominant in human plasma following escalating oral micro-dosing with [14C]-BaP. Environ Int 159, 107045. doi:10.1016/j.envint.2021.107045
Walsh, T. J., Tilson, H. A., DeHaven, D. L. et al. (1984). AF64A, a cholinergic neurotoxin, selectively depletes acetylcholine in hippocampus and cortex, and produces long-term passive avoidance and radial-arm maze deficits in the rat. Brain Res 321, 91–102. doi:10.1016/0006-8993(84)90684-x
Wan, C., Pan, S., Lin, L. et al. (2021). DNA Methylation Biomarkers of IQ Reduction are Associated with Long-term Lead Exposure in School Aged Children in Southern China. Environ Sci Technol 55, 412–422. doi:10.1021/acs.est.0c01696
Weinhouse, C., Truong, L., Meyer, J. N. et al. (2018). Caenorhabditis elegans as an emerging model system in environmental epigenetics. Environ Mol Mutagen 59, 560–575. doi:10.1002/em.22203
Williams, P. L. and Dusenbery, D. B. (1988). Using the nematode Caenorhabditis elegans to predict mammalian acute lethality to metallic salts. Toxicol Ind Health 4, 469–78. doi:10.1177/074823378800400406
Witvliet, D., Mulcahy, B., Mitchell, J. K. et al. (2021). Connectomes across development reveal principles of brain maturation. Nature 596, 257–261. doi:10.1038/s41586-021-03778-8
Wu, Z., Ghosh-Roy, A., Yanik, M. F. et al. (2007). Caenorhabditis elegans neuronal regeneration is influenced by life stage, ephrin signaling, and synaptic branching. Proc Natl Acad Sci U S A 104, 15132–7. doi:10.1073/pnas.0707001104
Xiong, H., Pears, C. and Woollard, A. (2017). An enhanced C. elegans based platform for toxicity assessment. Sci Rep 7, 9839. doi:10.1038/s41598-017-10454-3
Yang, Z., Yang, S., Qian, S. Y. et al. (2007). Cadmium-induced toxicity in rat primary mid-brain neuroglia cultures: role of oxidative stress from microglia. Toxicol Sci 98, 488–94. doi:10.1093/toxsci/kfm106
Yemini, E., Lin, A., Nejatbakhsh, A. et al. (2021). NeuroPAL: A Multicolor Atlas for Whole-Brain Neuronal Identification in C. elegans. Cell 184, 272-288.e11. doi:10.1016/j.cell.2020.12.012
Zachariah, P. K., Slaga, T. J., Berry, D. L. et al. (1977). The ability of enteric bacteria to catalyze the covalent binding of bile acids and cholesterol to DNA and their in ability to metabolize benzo(a)pyrene to a binding product and to known metabolites. Cancer Lett 3, 99–105. doi:10.1016/s0304-3835(77)94577-3
van der Zalm, A. J., Barroso, J., Browne, P. et al. (2022). A framework for establishing scientific confidence in new approach methodologies. Arch Toxicol 96, 2865–2879. doi:10.1007/s00204-022-03365-4
Zhou, M., Tian, X. and Suszkiw, J. B. (2000). Developmental stage-dependent protective effect of NGF against lead cholinotoxicity in the rat septum. Brain Res 866, 268–73. doi:10.1016/s0006-8993(00)02265-4
Zhou, R., Zhao, J., Li, D. et al. (2020). Combined exposure of lead and cadmium leads to the aggravated neurotoxicity through regulating the expression of histone deacetylase 2. Chemosphere 252, 126589. doi:10.1016/j.chemosphere.2020.126589
Zou, Y., Chiu, H., Zinovyeva, A. et al. (2013). Developmental decline in neuronal regeneration by the progressive change of two intrinsic timers. Science 340, 372–376. doi:10.1126/science.1231321