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Lopicic S, Svirčev Z, Palanački Malešević T, Kopitović A, Ivanovska A, Meriluoto J. Environmental Neurotoxin β- N-Methylamino-L-alanine (BMAA) as a Widely Occurring Putative Pathogenic Factor in Neurodegenerative Diseases. Microorganisms 2022; 10:2418. [PMID: 36557671 PMCID: PMC9781992 DOI: 10.3390/microorganisms10122418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
In the present review we have discussed the occurrence of β-N-methylamino-L-alanine (BMAA) and its natural isomers, and the organisms and sample types in which the toxin(s) have been detected. Further, the review discusses general pathogenic mechanisms of neurodegenerative diseases, and how modes of action of BMAA fit in those mechanisms. The biogeography of BMAA occurrence presented here contributes to the planning of epidemiological research based on the geographical distribution of BMAA and human exposure. Analysis of BMAA mechanisms in relation to pathogenic processes of neurodegeneration is used to critically assess the potential significance of the amino acid as well as to identify gaps in our understanding. Taken together, these two approaches provide the basis for the discussion on the potential role of BMAA as a secondary factor in neurodegenerative diseases, the rationale for further research and possible directions the research can take, which are outlined in the conclusions.
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Affiliation(s)
- Srdjan Lopicic
- Faculty of Medicine, University of Belgrade, Dr Subotića Starijeg 8, 11000 Belgrade, Serbia
| | - Zorica Svirčev
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Tamara Palanački Malešević
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
| | - Aleksandar Kopitović
- Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia
| | - Aleksandra Ivanovska
- Innovation Center of the Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
| | - Jussi Meriluoto
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
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Kazemi Shariat Panahi H, Dehhaghi M, Heng B, Lane DJR, Bush AI, Guillemin GJ, Tan VX. Neuropathological Mechanisms of β-N-Methylamino-L-Alanine (BMAA) with a Focus on Iron Overload and Ferroptosis. Neurotox Res 2022; 40:614-635. [PMID: 35023054 DOI: 10.1007/s12640-021-00455-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 11/22/2021] [Accepted: 11/30/2021] [Indexed: 02/08/2023]
Abstract
The incidence of neurodegenerative diseases and cyanobacterial blooms is concomitantly increasing worldwide. The cyanotoxin β-N-methylamino-L-alanine (BMAA) is produced by most of the Cyanobacteria spp. This cyanotoxin is described as a potential environmental etiology factor for some sporadic neurodegenerative diseases. Climate change and eutrophication significantly increase the frequency and intensity of cyanobacterial bloom in water bodies. This review evaluates different neuropathological mechanisms of BMAA at molecular and cellular levels and compares the related studies to provide some useful recommendations. Additionally, the structure and properties of BMAA as well as its microbial origin, especially by gut bacteria, are also briefly covered. Unlike previous reviews, we hypothesize the possible neurotoxic mechanism of BMAA through iron overload. We also discuss the involvement of BMAA in excitotoxicity, TAR DNA-binding protein 43 (TDP-43) translocation and accumulation, tauopathy, and other protein misincorporation and misfolding.
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Affiliation(s)
- Hamed Kazemi Shariat Panahi
- Neuroinflammation Group, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mona Dehhaghi
- Neuroinflammation Group, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
- PANDIS.Org, Bendigo, Australia
- Department of Microbial Biotechnology, School of Biology and Centre of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran
| | - Benjamin Heng
- Neuroinflammation Group, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Darius J R Lane
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Gilles J Guillemin
- Neuroinflammation Group, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia.
- PANDIS.Org, Bendigo, Australia.
| | - Vanessa X Tan
- Neuroinflammation Group, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
- PANDIS.Org, Bendigo, Australia
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Transfer of the Neurotoxin β- N-methylamino-l-alanine (BMAA) in the Agro-Aqua Cycle. Mar Drugs 2020; 18:md18050244. [PMID: 32384637 PMCID: PMC7281744 DOI: 10.3390/md18050244] [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: 03/24/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 12/30/2022] Open
Abstract
The neurotoxic non-protein amino acid β-N-methylamino-l-alanine (BMAA) is connected to the development of neurodegenerative diseases. BMAA has been shown to accumulate in aquatic ecosystems, and filter-feeding molluscs seem particularly susceptible to BMAA accumulation. The blue mussels farmed along the Swedish coastline in the Baltic Sea are, due to their small size, exclusively used to produce feed for chicken and fish in the agro-aqua cycle. We have investigated the possible biotransfer of BMAA from mussels, via mussel-based feed, into chickens. Chickens were divided into two groups, the control and the treatment. BMAA was extracted from the muscle, liver, brain, and eye tissues in both chicken groups; a UPLC-MS/MS method was subsequently used to quantify BMAA. The results indicate detectable concentrations of BMAA in both chicken groups. However, the BMAA concentration in chicken was 5.65 times higher in the treatment group than the control group, with the highest concentration found in muscle tissue extracted from the treatment group chickens. These data suggest that there is a BMAA transfer route within the agro-aqua cycle, so further investigation is recommended before using mussel-based feed in the chicken industry.
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Manolidi K, Triantis TM, Kaloudis T, Hiskia A. Neurotoxin BMAA and its isomeric amino acids in cyanobacteria and cyanobacteria-based food supplements. JOURNAL OF HAZARDOUS MATERIALS 2019; 365:346-365. [PMID: 30448548 DOI: 10.1016/j.jhazmat.2018.10.084] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 06/09/2023]
Abstract
Cyanobacteria are photosynthetic microorganisms distributed globally in aquatic and terrestrial environments. They are also industrially cultivated to be used as dietary supplements, as they have a high nutritional value; however, they are also known to produce a wide range of toxic secondary metabolites, called cyanotoxins. BMAA (β-methylamino-l-alanine) and its most common structural isomers, DAB (2,4-diaminobutyric acid) and AEG (N-2-aminoethylglycine) produced by cyanobacteria, are non-proteinogenic amino acids that have been associated with neurodegenerative diseases. A possible route of exposure to those amino acids is through consumption of food supplements based on cyanobacteria. The review critically discusses existing reports regarding the occurrence of BMAA, DAB and AEG in cyanobacteria and cyanobacteria-based food supplements. It is shown that inconsistencies in reported results could be attributed to performance of different methods of extraction and analysis applied and in ambiguities regarding determination of soluble and bound fractions of the compounds. The critical aspect of this review aims to grow awareness of human intake of neurotoxic amino acids, while results presented in literature concerning dietary supplements aim to promote further research, quality control as well as development of guidelines for cyanotoxins in food products.
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Affiliation(s)
- Korina Manolidi
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "DEMOKRITOS", Patriarchou Grigoriou E' & Neapoleos 27, 15341, Athens, Greece; National and Kapodistrian University of Athens, Faculty of Chemistry, 15784, Panepistimiopolis, Athens, Greece.
| | - Theodoros M Triantis
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "DEMOKRITOS", Patriarchou Grigoriou E' & Neapoleos 27, 15341, Athens, Greece.
| | - Triantafyllos Kaloudis
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "DEMOKRITOS", Patriarchou Grigoriou E' & Neapoleos 27, 15341, Athens, Greece; Water Quality Control Department, Athens Water Supply and Sewerage Company - EYDAP SA, Athens, Greece.
| | - Anastasia Hiskia
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "DEMOKRITOS", Patriarchou Grigoriou E' & Neapoleos 27, 15341, Athens, Greece.
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Scott LL, Downing TG. A Single Neonatal Exposure to BMAA in a Rat Model Produces Neuropathology Consistent with Neurodegenerative Diseases. Toxins (Basel) 2017; 10:E22. [PMID: 29286334 PMCID: PMC5793109 DOI: 10.3390/toxins10010022] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/23/2017] [Accepted: 12/27/2017] [Indexed: 12/11/2022] Open
Abstract
Although cyanobacterial β-N-methylamino-l-alanine (BMAA) has been implicated in the development of Alzheimer's Disease (AD), Parkinson's Disease (PD) and Amyotrophic Lateral Sclerosis (ALS), no BMAA animal model has reproduced all the neuropathology typically associated with these neurodegenerative diseases. We present here a neonatal BMAA model that causes β-amyloid deposition, neurofibrillary tangles of hyper-phosphorylated tau, TDP-43 inclusions, Lewy bodies, microbleeds and microgliosis as well as severe neuronal loss in the hippocampus, striatum, substantia nigra pars compacta, and ventral horn of the spinal cord in rats following a single BMAA exposure. We also report here that BMAA exposure on particularly PND3, but also PND4 and 5, the critical period of neurogenesis in the rodent brain, is substantially more toxic than exposure to BMAA on G14, PND6, 7 and 10 which suggests that BMAA could potentially interfere with neonatal neurogenesis in rats. The observed selective toxicity of BMAA during neurogenesis and, in particular, the observed pattern of neuronal loss observed in BMAA-exposed rats suggest that BMAA elicits its effect by altering dopamine and/or serotonin signaling in rats.
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Affiliation(s)
- Laura Louise Scott
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - 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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Scott LL, Downing TG. Β-N-Methylamino-L-Alanine (BMAA) Toxicity Is Gender and Exposure-Age Dependent in Rats. Toxins (Basel) 2017; 10:E16. [PMID: 29280981 PMCID: PMC5793103 DOI: 10.3390/toxins10010016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/21/2017] [Accepted: 12/26/2017] [Indexed: 12/21/2022] Open
Abstract
Cyanobacterial β-N-methylamino-L-alanine (BMAA) has been suggested as a causative or contributory factor in the development of several neurodegenerative diseases. However, no BMAA animal model has adequately shown clinical or behavioral symptoms that correspond to those seen in either Alzheimer's Disease (AD), Amyotrophic Lateral Sclerosis (ALS) or Parkinson's Disease (PD). We present here the first data that show that when neonatal rats were exposed to BMAA on postnatal days 3, 4 and 5, but not on gestational day 14 or postnatally on days 7 or 10, several AD and/or PD-related behavioral, locomotor and cognitive deficits developed. Male rats exhibited severe unilateral hindlimb splay while whole body tremors could be observed in exposed female rats. BMAA-exposed rats failed to identify and discriminate a learned odor, an early non-motor symptom of PD, and exhibited decreased locomotor activity, decreased exploration and increased anxiety in the open field test. Alterations were also observed in the rats' natural passive defense mechanism, and potential memory deficits and changes to the rat's natural height avoidance behavior could be observed as early as PND 30. Spatial learning, short-term working, reference and long-term memory were also impaired in 90-day-old rats that had been exposed to a single dose of BMAA on PND 3-7. These data suggest that BMAA is a developmental neurotoxin, with specific target areas in the brain and spinal cord.
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Affiliation(s)
- Laura Louise Scott
- Department of Biochemistry and Microbiology, Nelson Mandela University, P.O. Box 77 000, Port Elizabeth 6031, South Africa.
| | - 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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Acute β-N-Methylamino-L-alanine Toxicity in a Mouse Model. J Toxicol 2015; 2015:739746. [PMID: 26604922 PMCID: PMC4641925 DOI: 10.1155/2015/739746] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 12/13/2022] Open
Abstract
The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) is considered to be an “excitotoxin,” and its suggested mechanism of action is killing neurons. Long-term exposure to L-BMAA is believed to lead to neurodegenerative diseases including Parkinson's and Alzheimer's diseases and amyotrophic lateral sclerosis (Lou Gehrig's disease). Objectives of this study were to determine the presumptive median lethal dose (LD50), the Lowest-Observed-Adverse-Effect Level (LOAEL), and histopathologic lesions caused by the naturally occurring BMAA isomer, L-BMAA, in mice. Seventy NIH Swiss Outbred mice (35 male and 35 female) were used. Treatment group mice were injected intraperitoneally with 0.03, 0.3, 1, 2, and 3 mg/g body weight L-BMAA, respectively, and control mice were sham-injected. The presumptive LD50 of L-BMAA was 3 mg/g BW and the LOAEL was 2 mg/g BW. There were no histopathologic lesions in brain, liver, heart, kidney, lung, or spleen in any of the mice during the 14-day study. L-BMAA was detected in brains and livers in all of treated mice but not in control mice. Males injected with 0.03 mg/g BW, 0.3 mg/g BW, and 3.0 mg/g BW L-BMAA showed consistently higher concentrations (P < 0.01) in brain and liver samples as compared to females in those respective groups.
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Koenig JH, Goto JJ, Ikeda K. Novel NMDA receptor-specific desensitization/inactivation produced by ingestion of the neurotoxins, β-N-methylamino-L-alanine (BMAA) or β-N-oxalylamino-L-alanine (BOAA/β-ODAP). Comp Biochem Physiol C Toxicol Pharmacol 2015; 167:43-50. [PMID: 25193276 DOI: 10.1016/j.cbpc.2014.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/16/2014] [Accepted: 08/26/2014] [Indexed: 10/24/2022]
Abstract
The environmental neurotoxins BMAA (β-N-methylamino-L-alanine) and BOAA (β-N-oxalylamino-L-alanine) are implicated as possible causative agents for the neurodegenerative diseases, amyotrophic lateral sclerosis/ParkinsonismDementia complex (ALS/PDC) and neurolathyrism, respectively. Both are structural analogs of the neurotransmitter, glutamate, and bind postsynaptic glutamate receptors. In this study, the effect of ingestion of these toxins on the response of a singly-innervated, identified, glutamatergic postsynaptic cell in a living, undissected Drosophila is observed by intracellular recording. Previously we have reported that ingested BMAA behaves as an NMDA agonist that produces an abnormal NMDA response in the postsynaptic cell. It is shown here that BOAA also behaves as an NMDA agonist, and produces an effect very similar to that of BMAA on the postsynaptic response. In response to a single stimulus, the amplitude of the NMDA component is decreased, while the time to peak and duration of the NMDA component are greatly increased. No discernable effect on the AMPA component of the response was observed. Furthermore, both BMAA and BOAA cause an NMDAR-specific desensitization in response to repetitive stimulation at the physiological frequency for the postsynaptic cell (5 Hz). The possibility that this phenomenon may represent a response to excessive Ca(2+) entry through NMDAR channels is discussed. This desensitization phenomenon, as well as the abnormal NMDAR gating characteristics induced by BMAA, appears to be rescued during higher frequency stimulation (e.g. 10, 20 Hz).
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Affiliation(s)
- Jane H Koenig
- Division of Neurosciences, Beckman Research Institute of the City of Hope Medical Center, 1450 E. Duarte Road, Duarte, CA 91010, USA.
| | - Joy J Goto
- Department of Chemistry, California State University, Fresno. 2555 East San Ramon Ave., MS SB 70, Fresno CA 93740, USA.
| | - Kazuo Ikeda
- Division of Neurosciences, Beckman Research Institute of the City of Hope Medical Center, 1450 E. Duarte Road, Duarte, CA 91010, USA.
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Goto JJ, Koenig JH, Ikeda K. The physiological effect of ingested β-N-methylamino-L-alanine on a glutamatergic synapse in an in vivo preparation. Comp Biochem Physiol C Toxicol Pharmacol 2012; 156:171-7. [PMID: 22841708 DOI: 10.1016/j.cbpc.2012.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/09/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022]
Abstract
The neurotoxin, BMAA (β-N-methylamino-L-alanine), may be a risk factor for amyotrophic lateral sclerosis (ALS), Parkinson's (PD) and Alzheimer's (AD) disease. In vivo experiments have demonstrated that BMAA can cause a number of motor dysfunctions if ingested or injected, and in vitro experiments show that this toxin binds to glutamate receptors with deleterious results. Also, BMAA exists in the human food chain worldwide, and has been detected in the brains of ALS and AD patients. This paper offers the first demonstration by intracellular recording of the effect of ingested BMAA on the postsynaptic response of an identified glutamatergic cell in a living, undissected organism (Drosophila melanogaster), and correlates these observations with the specific motor dysfunctions that result from ingestion. The results suggest that BMAA acts as a glutamate agonist, causing NMDA receptor channels to remain open for prolonged periods of time, thereby damaging the cell by excitotoxicity. The effect on the postsynaptic response became apparent days before the function of the postsynaptic cell (wing beat) became affected. Severely depolarized cells were able to fully recover with the removal of BMAA from the food source, suggesting that blocking BMAA binding in the brain might be a good treatment strategy.
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MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Amino Acids, Diamino/pharmacology
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Drosophila melanogaster/drug effects
- Drosophila melanogaster/physiology
- Excitatory Amino Acid Antagonists/pharmacology
- Female
- Motor Neurons/drug effects
- Motor Neurons/physiology
- Muscle Fibers, Skeletal/physiology
- Receptors, AMPA/antagonists & inhibitors
- Receptors, Glutamate/drug effects
- Receptors, Glutamate/physiology
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/physiology
- Synapses/drug effects
- Synapses/physiology
- Synaptic Potentials/drug effects
- Synaptic Potentials/physiology
- Wings, Animal/drug effects
- Wings, Animal/physiology
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Affiliation(s)
- Joy J Goto
- Department of Chemistry, California State University, Fresno, 2555 East San Ramon Ave., MS SB 70, Fresno, CA 93740, USA.
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Chiu AS, Gehringer MM, Welch JH, Neilan BA. Does α-amino-β-methylaminopropionic acid (BMAA) play a role in neurodegeneration? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:3728-46. [PMID: 22016712 PMCID: PMC3194113 DOI: 10.3390/ijerph8093728] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 09/09/2011] [Accepted: 09/09/2011] [Indexed: 12/13/2022]
Abstract
The association of α-amino-β-methylaminopropionic acid (BMAA) with elevated incidence of amyotrophic lateral sclerosis/Parkinson’s disease complex (ALS/PDC) was first identified on the island of Guam. BMAA has been shown to be produced across the cyanobacterial order and its detection has been reported in a variety of aquatic and terrestrial environments worldwide, suggesting that it is ubiquitous. Various in vivo studies on rats, mice, chicks and monkeys have shown that it can cause neurodegenerative symptoms such as ataxia and convulsions. Zebrafish research has also shown disruption to neural development after BMAA exposure. In vitro studies on mice, rats and leeches have shown that BMAA acts predominantly on motor neurons. Observed increases in the generation of reactive oxygen species (ROS) and Ca2+ influx, coupled with disruption to mitochondrial activity and general neuronal death, indicate that the main mode of activity is via excitotoxic mechanisms. The current review pertaining to the neurotoxicity of BMAA clearly demonstrates its ability to adversely affect neural tissues, and implicates it as a potentially significant compound in the aetiology of neurodegenerative disease. When considering the potential adverse health effects upon exposure to this compound, further research to better understand the modes of toxicity of BMAA and the environmental exposure limits is essential.
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Affiliation(s)
- Alexander S Chiu
- The School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
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Excitatory amino acid beta-N-methylamino-L-alanine is a putative environmental neurotoxin. JOURNAL OF THE SERBIAN CHEMICAL SOCIETY 2011. [DOI: 10.2298/jsc100629047l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The amino acid beta-N-methylamino-L-alanine (L-BMAA) has been associated with
the amyotrophic lateral sclerosis/parkinsonismdementia complex in three
distinct western Pacific populations. The putative neurotoxin is produced by
cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA
was thought to be a threat only to those few populations whose diet and
medicines rely heavily on cycad seeds. However, the recent discovery that
cyanobacteria from diverse terrestrial, freshwater, and saltwater ecosystems
around the world produce the toxin requires a reassessment of whether it
poses a larger health threat. Therefore, it is proposed that monitoring
L-BMAA levels in cyanobacteria-contaminated water supplies might be prudent.
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Metabotropic glutamate receptor 1 mediates the electrophysiological and toxic actions of the cycad derivative beta-N-Methylamino-L-alanine on substantia nigra pars compacta DAergic neurons. J Neurosci 2010; 30:5176-88. [PMID: 20392940 DOI: 10.1523/jneurosci.5351-09.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amyotrophic lateral sclerosis-Parkinson dementia complex (ALS-PDC) is a neurodegenerative disease with ALS, parkinsonism, and Alzheimer's symptoms that is prevalent in the Guam population. beta-N-Methylamino alanine (BMAA) has been proposed as the toxic agent damaging several neuronal types in ALS-PDC, including substantia nigra pars compacta dopaminergic (SNpc DAergic) neurons. BMAA is a mixed glutamate receptor agonist, but the specific pathways activated in DAergic neurons are not yet known. We combined electrophysiology, microfluorometry, and confocal microscopy analysis to monitor membrane potential/current, cytosolic calcium concentration ([Ca(2+)](i)) changes, cytochrome-c (cyt-c) immunoreactivity, and reactive oxygen species (ROS) production induced by BMAA. Rapid toxin applications caused reversible membrane depolarization/inward current and increase of firing rate and [Ca(2+)](i) in DAergic neurons. The inward current (I(BMAA)) was mainly mediated by activation of metabotropic glutamate receptor 1 (mGluR1), coupled to transient receptor potential (TRP) channels, and to a lesser extent, AMPA receptors. Indeed, mGluR1 (CPCCOEt) and TRP channels (SKF 96365; Ruthenium Red) antagonists reduced I(BMAA), and a small component of I(BMAA) was reduced by the AMPA receptor antagonist CNQX. Calcium accumulation was mediated by mGluR1 but not by AMPA receptors. Application of a low concentration of NMDA potentiated the BMAA-mediated calcium increase. Prolonged exposure to BMAA caused significant modifications of membrane properties, calcium overload, cell shrinkage, massive cyt-c release into the cytosol and ROS production. In SNpc GABAergic neurons, BMAA activated only AMPA receptors. Our study identifies the mGluR1-activated mechanism induced by BMAA that may cause the neuronal degeneration and parkinsonian symptoms seen in ALS-PDC. Moreover, environmental exposure to BMAA might possibly also contribute to idiopathic PD.
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Santucci S, Zsürger N, Chabry J. β-N-methylamino-l-alanine inducedin vivoretinal cell death. J Neurochem 2009; 109:819-25. [DOI: 10.1111/j.1471-4159.2009.06022.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Karamyan VT, Speth RC. Animal models of BMAA neurotoxicity: a critical review. Life Sci 2007; 82:233-46. [PMID: 18191417 DOI: 10.1016/j.lfs.2007.11.020] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 11/20/2007] [Accepted: 11/26/2007] [Indexed: 01/26/2023]
Abstract
Of all the molecules reported to have toxicological effects, BMAA (beta-methylamino alanine) stands out as having the most checkered past. In the late 1960's it was reported to be a toxic component of the cycad flour consumed by Chamorros on Guam which caused the high incidence of amyotrophic lateral sclerosis (ALS) in Guam, that was associated with a Parkinson's disease-like dementia complex (ALS-PDC). However, because ALS-PDC is a slow onset disease, manifesting itself as long as 30 years following exposure to the putative neurotoxin, and only acute toxic effects of BMAA were observed in animal studies, interest in BMAA waned. A seminal study by Spencer et al., in 1987 showing neurological impairments with long-term BMAA-fed monkeys revived the hypothesis that BMAA could cause ALS-PDC. However, the amounts of BMAA used in that study were viewed as being the equivalent of a person consuming their body weight of cycad flour every day. Again, the BMAA hypothesis was discarded. Recently a third iteration of the BMAA hypothesis has been proposed. It is based on the discovery of a novel dietary source of BMAA via biomagnification of BMAA in flying foxes, once consumed in great amounts by Chamorros. Also, reports that BMAA can be incorporated into plant and animal proteins, a heretofore unrecognized dietary source of BMAA, further solidified this new hypothesis. However, once again this hypothesis has its detractors and it remains controversial. This manuscript critically evaluates in vivo studies directed at establishing an animal model of BMAA-induced ALS-PDC and their implications for this hypothesis.
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Affiliation(s)
- Vardan T Karamyan
- Department of Pharmacology, School of Pharmacy, University of Mississippi, MS 38677, USA
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Hägglund B, Sandberg G. Effect of L-alanine and some other amino acids on thymocyte proliferation in vivo. Immunobiology 1993; 188:62-9. [PMID: 8406560 DOI: 10.1016/s0171-2985(11)80487-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
L-alanine was shown earlier to play a significant role for the proliferation of lymphocytes in vitro. In the present work the effect of L-alanine and some other amino acids on thymocyte proliferation was studied in vivo by local administration into one thymus lobe of guinea pigs. Proliferating cells were pulse labelled with bromodeoxyuridine (BrdUrd). The labelling index of the treated lobe significantly exceeded that of the contralateral, control lobe at 48 h after treatment with 10 or 100 micrograms L-alanine, indicating stimulated proliferation. The higher dose, which was also tested after other time intervals, stimulated also at 24 h. The difference in proliferative activity between the lobes was verified by mitotic studies. The effect of L-alanine was mainly on the large, low density, highly proliferating precursor cells. No other amino acids tested (D-alanine, cysteine, hydroxyproline, serine, tryptophan), or pyruvate produced significant differences between the treated and control lobes.
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Affiliation(s)
- B Hägglund
- Department of Histology and Neurobiology, Karolinska Institute, Stockholm, Sweden
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Bridges RJ, Hatalski C, Shim SN, Nunn PB. Gliotoxic properties of the Lathyrus excitotoxin beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (beta-L-ODAP). Brain Res 1991; 561:262-8. [PMID: 1802342 DOI: 10.1016/0006-8993(91)91602-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
beta-N-Oxalyl-L-alpha,beta-diaminopropionic acid (beta-L-ODAP) is an excitatory amino acid agonist found in the seeds of Lathyrus sativus that is believed to be the major causative agent in the pathology of human lathyrism. We have found that in addition to its previously recognized neurotoxic properties, beta-L-ODAP is also gliotoxic. When added to cultures of neonatal rat astrocytes, beta-L-ODAP induced a series of morphological changes (e.g., extensive vacuole formation, pale and swollen nuclei with obvious nucleoli, and cellular swelling) that led to the eventual lysis of the glial cells. If the beta-L-ODAP was removed prior to the lysis of the astrocytes, many of the early morphological changes appeared to be reversible. When quantitated by a loss of the lactate dehydrogenase activity, beta-L-ODAP lysed the astrocytes with an LD50 of 2.1 +/- 0.2 mM following 48 h of exposure. Lower concentrations of beta-L-ODAP were found to be more toxic if the duration of the exposure was increased. The results suggest that the overall impact of the toxin on the CNS may represent the cumulative action of beta-L-ODAP at a number of distinct points on both neurons and astrocytes. The potential that these multiple sites of action may affect the normal regulation of extracellular glutamate and, consequently, disturb the balance between its normal and pathological roles is discussed.
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Affiliation(s)
- R J Bridges
- Department of Neurology, Irvine Research Unit on Brain Aging, University of California 92717
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