Protein association of the neurotoxin and non-protein amino acid BMAA (β-N-methylamino-L-alanine) in the liver and brain following neonatal administration in rats.
The environmental neurotoxin β-N-methylamino-L-alanine (BMAA) is not an amino acid that is normally found in proteins. Our previous autoradiographic study of (3)H-labeled BMAA in adult mice unexpectedly revealed a tissue distribution similar to that of protein amino acids. The aim of this study was to characterize the distribution of free and protein-bound BMAA in neonatal rat tissues following a short exposure using autoradiographic imaging and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The autoradiographic imaging of (14)C-L-BMAA demonstrated a distinct uptake of radioactivity that was retained following acid extraction in tissues with a high rate of cell turnover and/or protein synthesis. The UHPLC-MS/MS analysis conclusively demonstrated a dose-dependent increase of protein-associated BMAA in neonatal rat tissues. The level of protein-associated BMAA in the liver was more than 10 times higher than that in brain regions not fully protected by the blood-brain barrier which may be due to the higher rate of protein synthesis in the liver. In conclusion, this study demonstrated that BMAA was associated with rat proteins suggesting that BMAA may be misincorporated into proteins. However, protein-associated BMAA seemed to be cleared over time, as none of the samples from adult rats had any detectable free or protein-associated BMAA.
Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden; Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden. Electronic address: Oskar.Karlsson@farmbio.uu.se.
Oskar
O
Karlsson
Department of Analytical Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
Liying
L
Jiang
Department of Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden.
Marie
M
Andersson
Department of Analytical Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
Leopold L
LL
Ilag
Department of Pharmaceutical Biosciences, Uppsala University, SE-751 24 Uppsala, Sweden.
Eva B
EB
Brittebo
D000599:Amino Acids, Diamino / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D000087522:Cyanobacteria Toxins; D018690:Excitatory Amino Acid Agonists / Q000008:administration & dosage / Q000378:metabolism*; D007279:Injections, Subcutaneous; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D009498:Neurotoxins / Q000008:administration & dosage / Q000378:metabolism*; D011485:Protein Binding; D014176:Protein Biosynthesis; D011859:Radiography; D051381:Rats; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D014018:Tissue Distribution
D000599:Amino Acids, Diamino; D000087522:Cyanobacteria Toxins; D018690:Excitatory Amino Acid Agonists; D009498:Neurotoxins; C001824:beta-N-methylamino-L-alanine
ALS/PDC; Autoradiography; Cyanobacteria; Mass spectrometry; Misincorporation; N-(2-aminoethyl) glycine