Lead induces similar gene expression changes in brains of gestationally exposed adult mice and in neurons differentiated from mouse embryonic stem cells

• Published in: PloS one 2013-11, Vol.8 (11), p.e80558
• Main Authors: Sánchez-Martín, Francisco Javier, Fan, Yunxia, Lindquist, Diana M, Xia, Ying, Puga, Alvaro
• Format: Article
• Language: English
• Subjects: Adults; Animals; Attention deficit hyperactivity disorder; Biomarkers; Brain; Brain - metabolism; Brain-derived neurotrophic factor; Cell Differentiation - drug effects; Central nervous system; Cognitive ability; Contaminants; Crime; Differentiation; DNA binding proteins; Embryo cells; Embryonic stem cells; Embryonic Stem Cells - cytology; Embryonic Stem Cells - metabolism; Environmental changes; Environmental toxicology; Exposure; Female; Gene expression; Gene Expression Regulation, Developmental - drug effects; Genes; Glutamate; Glutamate receptors; Glutamatergic transmission; Glutamic acid receptors; Hippocampus; Kinases; Lead; Lead - toxicity; Lead content; Lead poisoning; Long-term effects; Maternal Exposure; Mice; Molecular modelling; Myelin; Neurodevelopment; Neuronal-glial interactions; Neurons; Neurons - cytology; Neurons - metabolism; Neurotoxicity; Neurotrophic factors; Pregnancy; Stem cell transplantation; Stem cells; Substantia grisea; Thalamus; Toxicants; Transcription (Genetics); Transcription factors; Zebrafish
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0080558

Exposure to environmental toxicants during embryonic life causes changes in the expression of developmental genes that may last for a lifetime and adversely affect the exposed individual. Developmental exposure to lead (Pb), an ubiquitous environmental contaminant, causes deficits in cognitive functions and IQ, behavioral effects, and attention deficit hyperactivity disorder (ADHD). Long-term effects observed after early life exposure to Pb include reduction of gray matter, alteration of myelin structure, and increment of criminal behavior in adults. Despite growing research interest, the molecular mechanisms responsible for the effects of lead in the central nervous system are still largely unknown. To study the molecular changes due to Pb exposure during neurodevelopment, we exposed mice to Pb in utero and examined the expression of neural markers, neurotrophins, transcription factors and glutamate-related genes in hippocampus, cortex, and thalamus at postnatal day 60. We found that hippocampus was the area where gene expression changes due to Pb exposure were more pronounced. To recapitulate gestational Pb exposure in vitro, we differentiated mouse embryonic stem cells (ESC) into neurons and treated ESC-derived neurons with Pb for the length of the differentiation process. These neurons expressed the characteristic neuronal markers Tubb3, Syp, Gap43, Hud, Ngn1, Vglut1 (a marker of glutamatergic neurons), and all the glutamate receptor subunits, but not the glial marker Gafp. Importantly, several of the changes observed in Pb-exposed mouse brains in vivo were also observed in Pb-treated ESC-derived neurons, including those affecting expression of Ngn1, Bdnf exon IV, Grin1, Grin2D, Grik5, Gria4, and Grm6. We conclude that our ESC-derived model of toxicant exposure during neural differentiation promises to be a useful model to analyze mechanisms of neurotoxicity induced by Pb and other environmental agents.