TY  - JOUR
A1  - Schumacher, Fabian
A1  - Chakraborty, Sudipta
A1  - Kleuser, Burkhard
A1  - Gulbins, Erich
A1  - Schwerdtle, Tanja
A1  - Aschner, Michael A.
A1  - Bornhorst, Julia
T1  - Highly sensitive isotope-dilution liquid-chromatography-electrospray ionization-tandem-mass spectrometry approach to study the drug-mediated modulation of dopamine and serotonin levels in Caenorhabditis elegans
JF  - Talanta : the international journal of pure and applied analytical chemistry
N2  - Dopamine (DA) and serotonin (SRT) are monoamine neurotransmitters that play a key role in regulating the central and peripheral nervous system. Their impaired metabolism has been implicated in several neurological disorders, such as Parkinson's disease and depression. Consequently, it is imperative to monitor changes in levels of these low-abundant neurotransmitters and their role in mediating disease. For the first time, a rapid, specific and sensitive isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of DA and SRT in the nematode Caenorhabditis elegans (C. elegans). This model organism offers a unique approach for studying the effect of various drugs and environmental conditions on neurotransmitter levels, given by the conserved DA and SRT biology, including synaptic release, trafficking and formation. We introduce a novel sample preparation protocol incorporating the usage of sodium thiosulfate in perchloric acid as extraction medium that assures high recovery of the relatively unstable neurotransmitters monitored. Moreover, the use of both deuterated internal standards and the multiple reaction monitoring (MRM) technique allows for unequivocal quantification. Thereby, to the best of our knowledge, we achieve a detection sensitivity that clearly exceeds those of published DA and SRT quantification methods in various matrices. We are the first to show that exposure of C elegans to the monoamine oxidase B (MAOB) inhibitor selegiline or the catechol-O-methyltransferase (COMT) inhibitor tolcapone, in order to block DA and SRT degradation, resulted in accumulation of the respective neurotransmitter. Assessment of a behavioral output of the dopaminergic system (basal slowing response) corroborated the analytical LC-MS/MS data. Thus, utilization of the C elegans model system in conjunction with our analytical method is well-suited to investigate drug-mediated modulation of the DA and SRT system in order to identify compounds with neuroprotective or regenerative properties. (C) 2015 Elsevier B.V. All rights reserved.
KW  - Caenorhabditis elegans
KW  - Dopamine
KW  - Serotonin
KW  - Liquid chromatography-tandem mass spectrometry
KW  - Isotope-dilution analysis
Y1  - 2015
U6  - https://doi.org/10.1016/j.talanta.2015.05.057
SN  - 0039-9140
SN  - 1873-3573
VL  - 144
SP  - 71
EP  - 79
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Peres, Tanara V.
A1  - Horning, Kyle J.
A1  - Bornhorst, Julia
A1  - Schwerdtle, Tanja
A1  - Bowman, Aaron B.
A1  - Aschner, Michael
T1  - Small Molecule Modifiers of In Vitro Manganese Transport Alter Toxicity In Vivo
JF  - Biological Trace Element Research
N2  - Manganese (Mn) is essential for several species and daily requirements are commonly met by an adequate diet. Mn overload may cause motor and psychiatric disturbances and may arise from an impaired or not fully developed excretion system, transporter malfunction and/or exposure to excessive levels of Mn. Therefore, deciphering processes regulating neuronal Mn homeostasis is essential to understand the mechanisms of Mn neurotoxicity. In the present study, we selected two small molecules (with opposing effects on Mn transport) from a previous high throughput screen of 40,167 to test their effects on Mn toxicity parameters in vivo using Caenorhabditis elegans. We pre-exposed worms to VU0063088 and VU0026921 for 30min followed by co-exposure for 1h with Mn and evaluated Mn accumulation, dopaminergic (DAergic) degeneration and worm survival. Control worms were exposed to vehicle (DMSO) and saline only. In pdat-1::GFP worms, with GFP labeled DAergic neurons, we observed a decrease of Mn-induced DAergic degeneration in the presence of both small molecules. This effect was also observed in an smf-2 knockout strain. SMF-2 is a regulator of Mn transport in the worms and this strain accumulates higher Mn levels. We did not observe improved survival in the presence of small molecules. Our results suggest that both VU0063088 and VU0026921 may modulate Mn levels in the worms through a mechanism that does not require SMF-2 and induce protection against Mn neurotoxicity.
KW  - Small molecules
KW  - Manganese
KW  - Neurotoxicity
KW  - C. elegans
KW  - Dopamine
Y1  - 2018
U6  - https://doi.org/10.1007/s12011-018-1531-7
SN  - 0163-4984
SN  - 1559-0720
VL  - 188
IS  - 1
SP  - 127
EP  - 134
PB  - Human press inc.
CY  - Totowa
ER  -