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Xie J, Wu S, Szadowski H, Min S, Yang Y, Bowman AB, Rochet JC, Freeman JL, Yuan C. Developmental Pb exposure increases AD risk via altered intracellular Ca 2+ homeostasis in hiPSC-derived cortical neurons. J Biol Chem 2023; 299:105023. [PMID: 37423307 PMCID: PMC10413359 DOI: 10.1016/j.jbc.2023.105023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/11/2023] Open
Abstract
Exposure to environmental chemicals such as lead (Pb) during vulnerable developmental periods can result in adverse health outcomes later in life. Human cohort studies have demonstrated associations between developmental Pb exposure and Alzheimer's disease (AD) onset in later life which were further corroborated by findings from animal studies. The molecular pathway linking developmental Pb exposure and increased AD risk, however, remains elusive. In this work, we used human iPSC-derived cortical neurons as a model system to study the effects of Pb exposure on AD-like pathogenesis in human cortical neurons. We exposed neural progenitor cells derived from human iPSC to 0, 15, and 50 ppb Pb for 48 h, removed Pb-containing medium, and further differentiated them into cortical neurons. Immunofluorescence, Western blotting, RNA-sequencing, ELISA, and FRET reporter cell lines were used to determine changes in AD-like pathogenesis in differentiated cortical neurons. Exposing neural progenitor cells to low-dose Pb, mimicking a developmental exposure, can result in altered neurite morphology. Differentiated neurons exhibit altered calcium homeostasis, synaptic plasticity, and epigenetic landscape along with elevated AD-like pathogenesis markers, including phosphorylated tau, tau aggregates, and Aβ42/40. Collectively, our findings provide an evidence base for Ca dysregulation caused by developmental Pb exposure as a plausible molecular mechanism accounting for increased AD risk in populations with developmental Pb exposure.
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Affiliation(s)
- Junkai Xie
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Shichen Wu
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Hailey Szadowski
- Agriculture and Biological Engineering, Purdue University, West Lafayette, Indiana, USA
| | - Sehong Min
- Department of Medicinal Chemistry and Molecular Pharmacy, Purdue University, West Lafayette, Indiana, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacy, Purdue University, West Lafayette, Indiana, USA; Purdue Institute of Integrated Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Aaron B Bowman
- Purdue Institute of Integrated Neuroscience, Purdue University, West Lafayette, Indiana, USA; School of Health Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Jean-Christophe Rochet
- Department of Medicinal Chemistry and Molecular Pharmacy, Purdue University, West Lafayette, Indiana, USA; Purdue Institute of Integrated Neuroscience, Purdue University, West Lafayette, Indiana, USA
| | - Jennifer L Freeman
- Purdue Institute of Integrated Neuroscience, Purdue University, West Lafayette, Indiana, USA; School of Health Sciences, Purdue University, West Lafayette, Indiana, USA; Purdue Center of Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, USA; Purdue Institute of Integrated Neuroscience, Purdue University, West Lafayette, Indiana, USA; Purdue Center of Cancer Research, Purdue University, West Lafayette, Indiana, USA.
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Ambrose N, Rodriguez M, Waters KA, Machaalani R. Microglia in the human infant brain and factors that affect expression. Brain Behav Immun Health 2020; 7:100117. [PMID: 34589874 PMCID: PMC8474518 DOI: 10.1016/j.bbih.2020.100117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/21/2022] Open
Abstract
The present study reports on the microglial populations present in 34 regions of the human infant brain (1-11 months), and whether developmental parameters or extrinsic factors such as cigarette smoke exposure, prone sleeping and an upper respiratory tract infection (URTI) influence their expression. Further, we compare microglia populations amongst three sudden unexpected death in infancy (SUDI) sub-groups: explained SUDI (eSUDI, n = 7), sudden infant death syndrome (SIDS) I (n = 8) and SIDS II (n = 13). Ionised calcium binding adaptor molecule-1 (Iba1) was used to determine the morphology and area covered by microglia in a given brain region. Activation was explored using cluster-of-differentiation factor 68 (CD68) and human leukocyte antigen-DP,DQ,DR (HLA). We found regional heterogeneity in the area covered and activation status of microglia across the infant brain. The hippocampus, basal ganglia, white matter and dentate nucleus of the cerebellum showed larger areas of Iba1, while the brainstem had the smallest. Microglia in regions of the basal ganglia and cortex demonstrated positive correlations with infant developmental parameters, while in nuclei of the rostral medulla, negative correlations between microglia parameters were seen. URTI and cigarette smoke exposure were associated with a reduced microglial area in regions of the hippocampus and cortex (parietal and occipital), respectively. In the context of SIDS, a reduced microglial area was seen in SIDS II and fewer SIDS I infants demonstrated activated phenotypes in the hippocampus. Overall, we identify the distribution of microglia in the infant brain to be heterogenous, and influenced by intrinsic and extrinsic factors, and that the SIDS I group is a useful control group for future research into other infant CNS pathologies.
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Affiliation(s)
- Natalie Ambrose
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Michael Rodriguez
- Department of Pathology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Karen A. Waters
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
- Discipline of Child and Adolescent Health, Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Rita Machaalani
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
- Discipline of Child and Adolescent Health, Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
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Liu JYW, Matarin M, Reeves C, McEvoy AW, Miserocchi A, Thompson P, Sisodiya SM, Thom M. Doublecortin-expressing cell types in temporal lobe epilepsy. Acta Neuropathol Commun 2018; 6:60. [PMID: 30005693 PMCID: PMC6045867 DOI: 10.1186/s40478-018-0566-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/03/2018] [Indexed: 12/14/2022] Open
Abstract
Doublecortin (DCX) is widely regarded as a marker of immature and migrating neurons during development. While DCX expression persists in adults, particularly in the temporal lobe and neurogenic regions, it is unknown how seizures influence its expression. The aim of the present study was to explore the distribution and characteristics of DCX-expressing cells in surgical and postmortem samples from 40 adult and paediatric patients, with epilepsy and with or without hippocampal sclerosis (HS), compared to post mortem controls. The hippocampus (pes and body), parahippocampal gyrus, amygdala, temporal pole and temporal cortex were examined with DCX immunohistochemistry using four commercially-available DCX antibodies, labelled cells were quantified in different regions of interest as well as their co-expression with cell type specific markers (CD68, Iba1, GFAP, GFAP∂, nestin, SOX2, CD34, OLIG2, PDGFRβ, NeuN) and cell cycle marker (MCM2). Histological findings were compared with clinical data, as well as gene expression data obtained from the temporal cortex of 83 temporal lobe epilepsy cases with HS. DCX immunohistochemistry identified immature (Nestin−/NeuN−) neurons in layer II of the temporal neocortex in patients with and without epilepsy. Their number declined significantly with age but was not associated with the presence of hippocampal sclerosis, seizure semiology or memory dysfunction. DCX+ cells were prominent in the paralaminar nuclei and periamygdalar cortex and these declined with age but were not significantly associated with epilepsy history. DCX expressing cells with ramified processes were prominent in all regions, particularly in the hippocampal subgranular zone, where significantly increased numbers were observed in epilepsy samples compared to controls. DCX ramified cells co-expressed Iba1, CD68 and PDGFRβ, and less frequently MCM2, OLIG2 and SOX2, but no co-localization was observed with CD34, nestin or GFAP/GFAP ∂. Gene expression data from neocortical samples in patients with TLE and HS supported ongoing DCX expression in adults. We conclude that DCX identifies a range of morphological cell types in temporal lobe epilepsy, including immature populations, glial and microglial cell types. Their clinical relevance and biological function requires further study but we show some evidence for alteration with age and in epilepsy.
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