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Spencer PS, Valdes Angues R, Palmer VS. Nodding syndrome: A role for environmental biotoxins that dysregulate MECP2 expression? J Neurol Sci 2024; 462:123077. [PMID: 38850769 DOI: 10.1016/j.jns.2024.123077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 05/15/2024] [Accepted: 05/30/2024] [Indexed: 06/10/2024]
Abstract
Nodding syndrome is an epileptic encephalopathy associated with neuroinflammation and tauopathy. This initially pediatric brain disease, which has some clinical overlap with Methyl-CpG-binding protein 2 (MECP2) Duplication Syndrome, has impacted certain impoverished East African communities coincident with local civil conflict and internal displacement, conditions that forced dependence on contaminated food and water. A potential role in Nodding syndrome for certain biotoxins (freshwater cyanotoxins plus/minus mycotoxins) with neuroinflammatory, excitotoxic, tauopathic, and MECP2-dysregulating properties, is considered here for the first time.
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Affiliation(s)
- Peter S Spencer
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Gulu University School of Medicine, Gulu, Uganda.
| | - Raquel Valdes Angues
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
| | - Valerie S Palmer
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Gulu University School of Medicine, Gulu, Uganda
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2
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Sini P, Galleri G, Ciampelli C, Galioto M, Padedda BM, Lugliè A, Iaccarino C, Crosio C. Evaluation of cyanotoxin L-BMAA effect on α-synuclein and TDP43 proteinopathy. Front Immunol 2024; 15:1360068. [PMID: 38596666 PMCID: PMC11002123 DOI: 10.3389/fimmu.2024.1360068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/14/2024] [Indexed: 04/11/2024] Open
Abstract
The complex interplay between genetic and environmental factors is considered the cause of neurodegenerative diseases including Parkinson's disease (PD) and Amyotrophic Lateral Sclerosis (ALS). Among the environmental factors, toxins produced by cyanobacteria have received much attention due to the significant increase in cyanobacteria growth worldwide. In particular, L-BMAA toxin, produced by diverse taxa of cyanobacteria, dinoflagellates and diatoms, has been extensively correlated to neurodegeneration. The molecular mechanism of L-BMAA neurotoxicity is still cryptic and far from being understood. In this research article, we have investigated the molecular pathways altered by L-BMAA exposure in cell systems, highlighting a significant increase in specific stress pathways and an impairment in autophagic processes. Interestingly, these changes lead to the accumulation of both α-synuclein and TDP43, which are correlated with PD and ALS proteinopathy, respectively. Finally, we were able to demonstrate specific alterations of TDP43 WT or pathological mutants with respect to protein accumulation, aggregation and cytoplasmic translocation, some of the typical features of both sporadic and familial ALS.
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Affiliation(s)
- Paola Sini
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Grazia Galleri
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Cristina Ciampelli
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Manuela Galioto
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Bachisio Mario Padedda
- Laboratory of Ecology, Department of Architecture, Design and Urban Planning, University of Sassari, Sassari, Italy
| | - Antonella Lugliè
- Laboratory of Ecology, Department of Architecture, Design and Urban Planning, University of Sassari, Sassari, Italy
| | - Ciro Iaccarino
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Claudia Crosio
- Laboratory of Molecular Biology, Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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3
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Anzilotti S, Valente V, Brancaccio P, Franco C, Casamassa A, Lombardi G, Palazzi A, Conte A, Paladino S, Canzoniero LMT, Annunziato L, Pierantoni GM, Pignataro G. Chronic exposure to l-BMAA cyanotoxin induces cytoplasmic TDP-43 accumulation and glial activation, reproducing an amyotrophic lateral sclerosis-like phenotype in mice. Biomed Pharmacother 2023; 167:115503. [PMID: 37729728 DOI: 10.1016/j.biopha.2023.115503] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/24/2023] [Accepted: 09/12/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a progressive and often fatal neurodegenerative disease characterized by the loss of Motor Neurons (MNs) in spinal cord, motor cortex and brainstem. Despite significant efforts in the field, the exact pathogenetic mechanisms underlying both familial and sporadic forms of ALS have not been fully elucidated, and the therapeutic possibilities are still very limited. Here we investigate the molecular mechanisms of neurodegeneration induced by chronic exposure to the environmental cyanotoxin L-BMAA, which causes a form of ALS/Parkinson's disease (PD) in several populations consuming food and/or water containing high amounts of this compound. METHODS In this effort, mice were chronically exposed to L-BMAA and analyzed at different time points to evaluate cellular and molecular alterations and behavioral deficits, performing MTT assay, immunoblot, immunofluorescence and immunohistochemistry analysis, and behavioral tests. RESULTS We found that cyanotoxin L-BMAA determines apoptotic cell death and a marked astrogliosis in spinal cord and motor cortex, and induces neurotoxicity by favoring TDP-43 cytoplasmic accumulation. CONCLUSIONS Overall, our results characterize a new versatile neurotoxic animal model of ALS that may be useful for the identification of new druggable targets to develop innovative therapeutic strategies for this disease.
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Affiliation(s)
- Serenella Anzilotti
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | - Valeria Valente
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, "Federico II" University of Naples, Italy
| | - Paola Brancaccio
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Italy
| | - Cristina Franco
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | | | - Giovanna Lombardi
- Department of Science and Technology, University of Sannio, 82100 Benevento, Italy
| | - Alessandra Palazzi
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, "Federico II" University of Naples, Italy
| | - Andrea Conte
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, "Federico II" University of Naples, Italy
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, "Federico II" University of Naples, Italy
| | | | | | - Giovanna Maria Pierantoni
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, "Federico II" University of Naples, Italy.
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatological Sciences, School of Medicine, "Federico II" University of Naples, Italy.
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4
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Garamszegi SP, Banack SA, Duque LL, Metcalf JS, Stommel EW, Cox PA, Davis DA. Detection of β-N-methylamino-l-alanine in postmortem olfactory bulbs of Alzheimer's disease patients using UHPLC-MS/MS: An autopsy case-series study. Toxicol Rep 2023; 10:87-96. [PMID: 36691605 PMCID: PMC9860447 DOI: 10.1016/j.toxrep.2023.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/21/2022] [Accepted: 01/05/2023] [Indexed: 01/08/2023] Open
Abstract
Introduction Cyanobacterial blooms produce toxins that may become aerosolized, increasing health risks through inhalation exposures. Health related effects on the lower respiratory tract caused by these toxins are becoming better understood. However, nasal exposures to cyanotoxins remain understudied, especially for those with neurotoxic potential. Here, we present a case series study evaluating exposure to β-N-methylamino-l-alanine (BMAA), a cyanobacterial toxin linked to neurodegenerative disease, in postmortem olfactory tissues of individuals with varying stages of Alzheimer's disease (AD). Methods Olfactory bulb (Ob) tissues were collected during autopsies performed between 2014 and 2017 from six South Florida brain donors (ages 47-78) with residences less than 140 m from a freshwater body. A triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) method validated according to peer AOAC International guidelines was used to detect BMAA and two BMAA isomers: 2,4-diaminobutyric acid (2,4-DAB) and N-(2-aminoethyl)glycine (AEG). Quantitative PCR was performed on the contralateral Ob to evaluate the relative expression of genes related to proinflammatory cytokines (IL-6 & IL-18), apoptotic pathways (CASP1 & BCL2), and mitochondrial stress (IRF1 & PINK1). Immunohistochemistry was also performed on the adjacent olfactory tract (Ot) to evaluate co-occurring neuropathology with BMAA tissue concentration. Results BMAA was detected in the Ob of all cases at a median concentration of 30.4 ng/g (Range <LLOQ - 488.4 ng/g). Structural isomers were also detected with median concentrations of 28.8 ng/g (AEG) and 103.6 ng/g (2,4-DAB). In addition, we found that cases with BMAA tissue concentrations above the <LLOQ also displayed increased expression of IL-6 (3.3-fold), CASP1 (1.7-fold), and IRF1 (1.6-fold). Reactive microglial, astrogliosis, myelinopathy, and neuronopathy of axonal processes in the Ot were also observed in cases with higher BMAA tissue concentrations. Conclusion Our study demonstrates that the cyanobacterial toxin BMAA can be detected in the olfactory pathway, a window to the brain, and its presence may increase the occurrence of proinflammatory cytokines, reactive glia, and toxicity to axonal processes. Further studies will be needed to evaluate BMAA's toxicity via this route of exposure and factors that increase susceptibility.
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Key Words
- 2,4-DAB, 2,4-diaminobutyric acid
- AD, Alzheimer's disease
- AEG, N-(2-aminoethyl)glycine
- ALS/PDC, Amyotrophic lateral sclerosis/ parkinsonism dementia complex
- BMAA, β-N-methylamino-l-alanine
- CBs, Cyanobacterial blooms
- Cyanobacteria
- Cyanotoxin
- IL-6
- Inflammation
- OD, Olfactory dysfunction
- Ob, Olfactory bulb
- Olfactory dysfunction
- Ot, Olfactory tract
- UHPLC-MS/MS, Ultra-performance liquid chromatography and tandem mass spectrometry
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Affiliation(s)
- Susanna P. Garamszegi
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sandra Anne Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Linda L. Duque
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - James S. Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - Elijah W. Stommel
- Department of Neurology, Dartmouth-Hitchcock Medical Center Department of Neurology, One Medical Center Dr., Lebanon, NH 03756, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Paul Alan Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY 83001, USA
| | - David A. Davis
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Corresponding author.
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5
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Newell ME, Adhikari S, Halden RU. Systematic and state-of the science review of the role of environmental factors in Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig's Disease. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152504. [PMID: 34971691 DOI: 10.1016/j.scitotenv.2021.152504] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
The etiology of sporadic amyotrophic lateral sclerosis (ALS) is still unclear. We evaluate environmental factors suspected to be associated with ALS for their potential linkage to disease causality and to model geographic distributions of susceptible populations and expected cases worldwide. A PRISMA systematic literature review was performed 2021. Bradford Hill criteria were used to identify and rank environmental factors and a secondary review of ALS diagnoses in population studies and ALS case or cohort studies was conducted. Prevalence rate projection informed estimates of impacted regions and populations. Among 1710 papers identified, 258 met the inclusion criteria, of which 173 responded to at least one of nine Bradford Hill criteria among 83 literature-identified ALS environmental factors. Environmental determinants of ALS in order of decreasing significance were β-N-methylamino-L-alanine (BMAA), formaldehyde, selenium, and heavy metals including manganese, mercury, zinc, and copper. Murine animal models were the most common methodology for exploring environmental factors. Another line of investigation of 62 population exposure studies implicated the same group of environmental agents (mean odds ratios): BMAA (2.32), formaldehyde (1.54), heavy metals (2.99), manganese (3.85), mercury (2.74), and zinc (2.78). An age-adjusted incidence model estimated current total ALS cases globally at ~85,000 people compared to only ~1600 cases projected from the reported ALS incidence in the literature. Modeling with the prevalence microscope equation forecasted an increase in U.S. ALS cases from 16,707 confirmed in 2015 to ~22,650 projected for 2040. Two orthogonal methods employed implicate BMAA, formaldehyde, manganese, mercury, and zinc as environmental factors with strong ALS associations. ALS cases likely are significantly underreported globally, and high vulnerability exists in regions with large aging populations. Recent studies on other diseases with environmental determinants suggest the need to consider additional potential triggers and mechanisms, including exposures to microbial agents and epigenetic modifications.
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Affiliation(s)
- Melanie Engstrom Newell
- Biodesign Center for Environmental Health Engineering, Biodesign Institute, Building B, Arizona State University, 1001 S McAllister Ave, Tempe, AZ 85281-8101, USA; School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA.
| | - Sangeet Adhikari
- Biodesign Center for Environmental Health Engineering, Biodesign Institute, Building B, Arizona State University, 1001 S McAllister Ave, Tempe, AZ 85281-8101, USA; School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA.
| | - Rolf U Halden
- Biodesign Center for Environmental Health Engineering, Biodesign Institute, Building B, Arizona State University, 1001 S McAllister Ave, Tempe, AZ 85281-8101, USA; School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA; School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA; OneWaterOneHealth, Arizona State University Foundation, 1001 S. McAllister Avenue, Tempe, AZ 85287-8101, USA; Global Futures Laboratory, Arizona State University, 800 S. Cady Mall, Tempe, AZ 85281, USA.
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6
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Ra D, Sa B, Sl B, Js M, Sj M, DA D, Ew S, O K, Eb B, Ad C, Vx T, Gg G, Pa C, Dc M, Wg B. Is Exposure to BMAA a Risk Factor for Neurodegenerative Diseases? A Response to a Critical Review of the BMAA Hypothesis. Neurotox Res 2021; 39:81-106. [PMID: 33547590 PMCID: PMC7904546 DOI: 10.1007/s12640-020-00302-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022]
Abstract
In a literature survey, Chernoff et al. (2017) dismissed the hypothesis that chronic exposure to β-N-methylamino-L-alanine (BMAA) may be a risk factor for progressive neurodegenerative disease. They question the growing scientific literature that suggests the following: (1) BMAA exposure causes ALS/PDC among the indigenous Chamorro people of Guam; (2) Guamanian ALS/PDC shares clinical and neuropathological features with Alzheimer's disease, Parkinson's disease, and ALS; (3) one possible mechanism for protein misfolds is misincorporation of BMAA into proteins as a substitute for L-serine; and (4) chronic exposure to BMAA through diet or environmental exposures to cyanobacterial blooms can cause neurodegenerative disease. We here identify multiple errors in their critique including the following: (1) their review selectively cites the published literature; (2) the authors reported favorably on HILIC methods of BMAA detection while the literature shows significant matrix effects and peak coelution in HILIC that may prevent detection and quantification of BMAA in cyanobacteria; (3) the authors build alternative arguments to the BMAA hypothesis, rather than explain the published literature which, to date, has been unable to refute the BMAA hypothesis; and (4) the authors erroneously attribute methods to incorrect studies, indicative of a failure to carefully consider all relevant publications. The lack of attention to BMAA research begins with the review's title which incorrectly refers to BMAA as a "non-essential" amino acid. Research regarding chronic exposure to BMAA as a cause of human neurodegenerative diseases is emerging and requires additional resources, validation, and research. Here, we propose strategies for improvement in the execution and reporting of analytical methods and the need for additional and well-executed inter-lab comparisons for BMAA quantitation. We emphasize the need for optimization and validation of analytical methods to ensure that they are fit-for-purpose. Although there remain gaps in the literature, an increasingly large body of data from multiple independent labs using orthogonal methods provides increasing evidence that chronic exposure to BMAA may be a risk factor for neurological illness.
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Affiliation(s)
- Dunlop Ra
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA.
| | - Banack Sa
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Bishop Sl
- Lewis Research Group, Faculty of Science, University of Calgary, Alberta, Canada
| | - Metcalf Js
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Murch Sj
- Department of Chemistry, University of British Columbia, Kelowna, BC, Canada
| | - Davis DA
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Stommel Ew
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Karlsson O
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Brittebo Eb
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | | | - Tan Vx
- Department of Biological Sciences, Macquarie University Centre for Motor Neuron Disease Research, Macquarie University, Ryde, Australia
| | - Guillemin Gg
- Department of Biological Sciences, Macquarie University Centre for Motor Neuron Disease Research, Macquarie University, Ryde, Australia
| | - Cox Pa
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Mash Dc
- Nova Southeastern University, Fort Lauderdale, FL, USA
| | - Bradley Wg
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL, USA
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7
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Davis DA, Cox PA, Banack SA, Lecusay PD, Garamszegi SP, Hagan MJ, Powell JT, Metcalf JS, Palmour RM, Beierschmitt A, Bradley WG, Mash DC. l-Serine Reduces Spinal Cord Pathology in a Vervet Model of Preclinical ALS/MND. J Neuropathol Exp Neurol 2020; 79:393-406. [PMID: 32077471 PMCID: PMC7092359 DOI: 10.1093/jnen/nlaa002] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022] Open
Abstract
The early neuropathological features of amyotrophic lateral sclerosis/motor neuron disease (ALS/MND) are protein aggregates in motor neurons and microglial activation. Similar pathology characterizes Guamanian ALS/Parkinsonism dementia complex, which may be triggered by the cyanotoxin β-N-methylamino-l-alanine (BMAA). We report here the occurrence of ALS/MND-type pathological changes in vervets (Chlorocebus sabaeus; n = 8) fed oral doses of a dry powder of BMAA HCl salt (210 mg/kg/day) for 140 days. Spinal cords and brains from toxin-exposed vervets were compared to controls fed rice flour (210 mg/kg/day) and to vervets coadministered equal amounts of BMAA and l-serine (210 mg/kg/day). Immunohistochemistry and quantitative image analysis were used to examine markers of ALS/MND and glial activation. UHPLC-MS/MS was used to confirm BMAA exposures in dosed vervets. Motor neuron degeneration was demonstrated in BMAA-dosed vervets by TDP-43+ proteinopathy in anterior horn cells, by reactive astrogliosis, by activated microglia, and by damage to myelinated axons in the lateral corticospinal tracts. Vervets dosed with BMAA + l-serine displayed reduced neuropathological changes. This study demonstrates that chronic dietary exposure to BMAA causes ALS/MND-type pathological changes in the vervet and coadministration of l-serine reduces the amount of reactive gliosis and the number of protein inclusions in motor neurons.
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Affiliation(s)
- David A Davis
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Paul Alan Cox
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Brain Chemistry Labs, Jackson Hole, Wyoming
| | - Sandra Anne Banack
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Brain Chemistry Labs, Jackson Hole, Wyoming
| | | | | | - Matthew J Hagan
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | | | - Roberta M Palmour
- Behavioural Science Foundation, St. Kitts and Nevis, West Indies.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Amy Beierschmitt
- Behavioural Science Foundation, St. Kitts and Nevis, West Indies.,Department of Clinical Sciences, Ross University School of Veterinary Medicine, St. Kitts and Nevis, West Indies
| | - Walter G Bradley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Deborah C Mash
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida.,Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Davie, Florida
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8
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Western Pacific ALS-PDC: Evidence implicating cycad genotoxins. J Neurol Sci 2020; 419:117185. [PMID: 33190068 DOI: 10.1016/j.jns.2020.117185] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 09/20/2020] [Accepted: 09/29/2020] [Indexed: 12/12/2022]
Abstract
Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex (ALS-PDC) is a disappearing neurodegenerative disorder of apparent environmental origin formerly hyperendemic among Chamorros of Guam-USA, Japanese residents of the Kii Peninsula, Honshu Island, Japan and Auyu-Jakai linguistic groups of Papua-Indonesia on the island of New Guinea. The most plausible etiology is exposure to genotoxins in seed of neurotoxic cycad plants formerly used for food and/or medicine. Primary suspicion falls on methylazoxymethanol (MAM), the aglycone of cycasin and on the non-protein amino acid β-N-methylamino-L-alanine, both of which are metabolized to formaldehyde. Human and animal studies suggest: (a) exposures occurred early in life and sometimes during late fetal brain development, (b) clinical expression of neurodegenerative disease appeared years or decades later, and (c) pathological changes in various tissues indicate the disease was not confined to the CNS. Experimental evidence points to toxic molecular mechanisms involving DNA damage, epigenetic changes, transcriptional mutagenesis, neuronal cell-cycle reactivation and perturbation of the ubiquitin-proteasome system that led to polyproteinopathy and culminated in neuronal degeneration. Lessons learned from research on ALS-PDC include: (a) familial disease may reflect common toxic exposures across generations, (b) primary disease prevention follows cessation of exposure to culpable environmental triggers; and (c) disease latency provides a prolonged period during which to intervene therapeutically. Exposure to genotoxic chemicals ("slow toxins") in the early stages of life should be considered in the search for the etiology of ALS-PDC-related neurodegenerative disorders, including sporadic forms of ALS, progressive supranuclear palsy and Alzheimer's disease.
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9
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Schneider T, Simpson C, Desai P, Tucker M, Lobner D. Neurotoxicity of isomers of the environmental toxin L-BMAA. Toxicon 2020; 184:175-179. [PMID: 32585217 DOI: 10.1016/j.toxicon.2020.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/03/2020] [Accepted: 06/17/2020] [Indexed: 02/01/2023]
Abstract
There is evidence that the environmental toxin β-N-methylamino-L-alanine (L-BMAA) may be involved in neurodegenerative diseases. However, a number of controversies exist regarding L-BMAA, one of which is the possibility that when assaying for L-BMAA, its isomers are being detected instead. There are at least four isomers of BMAA that are known to occur: L-BMAA, β-N-methylamino-D-alanine (D-BMAA), 2,4-diaminobutyric acid (DAB), and N-(2-aminoethyl)glycine (AEG). The fact that isomers of BMAA exist in nature also leads to the possibility that they are involved in toxicity. We set out to determine both the potency and the mechanism of toxicity of L-BMAA, D-BMAA, DAB, asnd AEG using primary cortical cultures. The results were surprising with the following order of potency of toxicity: AEG > DAB > D-BMAA > L-BMAA. These results suggest that AEG may be an overlooked neurotoxin. We found that AEG induced toxicity through mGluR5 receptors and induction of oxidative stress. While the potential role of L-BMAA in neurodegenerative diseases has been emphasized, other isomers of L-BMAA, particularly AEG, are actually more potent toxins, and could therefore potentially contribute to neurodegenerative diseases.
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Affiliation(s)
- Thomas Schneider
- Dept. of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426,Milwaukee, WI, 53233, USA
| | - Catherine Simpson
- Dept. of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426,Milwaukee, WI, 53233, USA
| | - Prachi Desai
- Dept. of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426,Milwaukee, WI, 53233, USA
| | - Madeleine Tucker
- Dept. of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426,Milwaukee, WI, 53233, USA
| | - Doug Lobner
- Dept. of Biomedical Sciences, Marquette University, 561 N. 15th Street, Rm 426,Milwaukee, WI, 53233, USA.
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10
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Bradley WG, Andrew AS, Traynor BJ, Chiò A, Butt TH, Stommel EW. Gene-Environment-Time Interactions in Neurodegenerative Diseases: Hypotheses and Research Approaches. Ann Neurosci 2018; 25:261-267. [PMID: 31000966 DOI: 10.1159/000495321] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS), Alzheimer's, and Parkinson's diseases are age-related neurodegenerative diseases. ALS is not a single entity but a syndrome with many different causes. In all 3 diseases, gene mutations account for only 10-15% of cases. Many environmental and lifestyle factors have been implicated as risk factors for ALS, though none have been proven to cause the disease. It is generally believed that ALS results from interactions between environmental risk factors and genetic predisposing factors. The advent of next-generation sequencing and recent advances in research into environmental risk factors offer the opportunity to investigate these interactions. Summary We propose a hypothesis to explain the syndrome of ALS based on the interaction of many individual environmental risk factors with many individual genetic predisposing factors. We hypothesize that there are many such combinations of individual, specific, genetic, and environmental factors, and that each combination can lead to the development of the syndrome of ALS. We also propose a hypothesis that explains the overlap between the age-related neurodegenerations and their genetic underpinnings. Age and duration of exposure are crucial factors in these age-related neurodegenerative diseases, and we consider how these may relate to gene-environment interactions. Key Messages To date, genetic studies and environmental studies have investigated the causes of ALS separately. We argue that this univariate approach will not lead to discoveries of important gene-environment interactions. We propose new research approaches to investigating gene-environment interactions based on these hypotheses.
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Affiliation(s)
- Walter G Bradley
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Angeline S Andrew
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Bryan J Traynor
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, Maryland, USA.,Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Adriano Chiò
- "Rita Levi Montalcini" Department of Neuroscience, University of Turin, Turin, Italy
| | - Tanya H Butt
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Elijah W Stommel
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Downing S, Scott LL, Zguna N, Downing TG. Human Scalp Hair as an Indicator of Exposure to the Environmental Toxin β-N-Methylamino-l-alanine. Toxins (Basel) 2017; 10:E14. [PMID: 29280954 PMCID: PMC5793101 DOI: 10.3390/toxins10010014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/18/2017] [Accepted: 12/25/2017] [Indexed: 12/12/2022] Open
Abstract
Dietary or aerosol exposure to the environmental neurotoxin β-N-methylamino-l-alanine (BMAA) is a putative risk factor for the development of sporadic neurodegenerative disease. There are many potential sources of BMAA in the environment, but BMAA presence and quantities are highly variable. It has been suggested that BMAA in human hair may serve as an indicator of exposure. We sought to evaluate the use of the BMAA content of human scalp hair as an indicator of exposure, as well as the correlation between specific lifestyle or dietary habits, reported as hypothesised exposure risk factors, and BMAA in hair. Scalp hair samples and questionnaires were collected from participants in a small residential village surrounding a freshwater impoundment renowned for toxic cyanobacterial blooms. Data suggested a positive correlation between hair BMAA content and consumption of shellfish, and possibly pork. No statistically significant correlations were observed between hair BMAA content and residential proximity to the water or any other variable. Hair BMAA content was highly variable, and in terms of exposure, probably reflects primarily dietary exposure. However, the BMAA content of human hair may be affected to a great extent by several other factors, and as such, should be used with caution when evaluating human BMAA exposure, or correlating exposure to neurodegenerative disease incidence.
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Affiliation(s)
- Simoné Downing
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - Laura Louise Scott
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - Nadezda Zguna
- Unit for Analytical Chemistry, Department of Environmental Science and Analytical Chemistry, Stockholm University, SE 106 91 Stockholm, Sweden.
| | - Timothy Grant Downing
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
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