Behavioral metabolomics: how behavioral data can guide metabolomics research on neuropsychiatric disorders.

INTRODUCTION: Metabolomics produces vast quantities of data but determining which metabolites are the most relevant to the disease or disorder of interest can be challenging. OBJECTIVES: This study sought to demonstrate how behavioral models of psychiatric disorders can be combined with metabolomics research to overcome this limitation. METHODS: We designed a preclinical, untargeted metabolomics procedure, that focuses on the determination of central metabolites relevant to substance use disorders that are (a) associated with changes in behavior produced by acute drug exposure and (b) impacted by repeated drug exposure. Untargeted metabolomics analysis was carried out on liquid chromatography-mass spectrometry data obtained from 336 microdialysis samples. Samples were collected from the medial striatum of male Sprague-Dawley (N = 21) rats whilst behavioral data were simultaneously collected as part of a (±)-3,4-methylenedioxymethamphetamine (MDMA)-induced behavioral sensitization experiment. Analysis was conducted by orthogonal partial least squares, where the Y variable was the behavioral data, and the X variables were the relative concentrations of the 737 detected features. RESULTS: MDMA and its derivatives, serotonin, and several dopamine/norepinephrine metabolites were the greatest predictors of acute MDMA-produced behavior. Subsequent univariate analyses showed that repeated MDMA exposure produced significant changes in MDMA metabolism, which may contribute to the increased abuse liability of the drug as a function of repeated exposure. CONCLUSION: These findings highlight how the inclusion of behavioral data can guide metabolomics data analysis and increase the relevance of the results to the phenotype of interest.

Design and Synthesis of a Compound Library Exploiting 5-Methoxyleoligin as Potential Cholesterol Efflux Promoter.

5-Methoxyleoligin and leoligin are natural occurring lignans derived from Edelweiss (Leontopodium nivale ssp. alpinum), displaying potent pro-angiogenic and pro-arteriogenic activity. Cholesterol efflux from macrophages is associated with reverse cholesterol transport which inhibits the development of cardiovascular disease. Within this study, we developed a modular and stereoselective total synthesis of 5-methoxyleoligin which can be readily used to prepare a novel compound library of related analogs. The target 5-methoxyleoligin was synthesized exploiting a recently disclosed modular route, which allows also rapid synthesis of analogous compounds. All obtained products were tested towards macrophage cholesterol efflux enhancement and the performance was compared to the parent compound leoligin. It was found that variation on the aryl moiety in 2-position of the furan ring allows optimization of the activity profile, whereas the ester-functionality does not tolerate significant alterations.

The role of extracellular serotonin and MDMA in the sensitizing effects of MDMA.

MDMA is a non-selective monoamine releasing stimulant with potent serotonergic effects - a pharmacological effect not typically associated with drugs of misuse or efficacious reinforcers. Nonetheless, MDMA is misused by humans and self-administered by laboratory animals. We have previously shown that repeated exposure to MDMA sensitized both the locomotor activating and reinforcing effects of MDMA in rats. Because repeated MDMA exposure often results in decreased markers of serotonin neurotransmission, it is possible that this might underlie the sensitizing effects of MDMA. This was examined in the current study. Male Sprague-Dawley rats were stereotaxically implanted with guide cannula in the medial striatum. They were then pre-treated with saline (n =  11) or MDMA (10 mg/kg, i.p.; n =  10), once daily for five days. Two-days later, all rats received ascending doses of MDMA (0.0, 5.0, 10.0, mg/kg, i.p.) administered at 2 hr intervals, during which locomotor activity was measured and microdialysis samples were collected. Microdialysates were analyzed using liquid chromatography-mass spectrometry and the concentrations of serotonin and MDMA were quantified. Acute MDMA administration produced dose-dependent increases in locomotor activity, which was significantly enhanced by MDMA pre-treatment. Acute MDMA also produced dose-dependent increases in medial-striatal serotonin and MDMA, but this was not impacted by MDMA pre-treatment. These results suggest that the sensitizing effects of MDMA are not due to changes in MDMA-produced synaptic overflow of serotonin in the medial striatum or the absorption/elimination of systemically administered MDMA. More likely candidates are alterations in serotonin receptor mechanisms and/or dopamine neurotransmission following repeated exposure.

Investigation of Leoligin Derivatives as NF-κΒ Inhibitory Agents.

The transcription factor NF-κB is an essential mediator of inflammation; thus, the identification of compounds that interfere with the NF-κB signaling pathway is an important topic. The natural products leoligin and 5-methoxyleoligin have served as a starting point for the development of NF-κB inhibitors. Using our modular total synthesis method of leoligin, modifications at two positions were undertaken and the effects of these modifications on the biological activity were investigated. The first modification concerned the ester functionality, where it was found that variations in this position have a significant influence, with bulky esters lacking Michael-acceptor properties being favored. Additionally, the substituents on the aryl group in position 2 of the tetrahydrofuran scaffold can vary to some extent, where it was found that a 3,4-dimethoxy and a 4-fluoro substitution pattern show comparable inhibitory efficiency.

Leoligin-inspired synthetic lignans with selectivity for cell-type and bioactivity relevant for cardiovascular disease.

Recently, a natural compound leoligin, a furan-type lignan, was discovered as an interesting hit compound with an anti-inflammatory pharmacological activity profile. We developed a modular and stereoselective approach for the synthesis of the edelweiss-derived lignan leoligin and used the synthetic route to rapidly prepare leoligin analogs even on the gram scale. Proof of concept of this approach together with cell-based bio-assays gained structural analogs with increased selectivity towards vascular smooth muscle versus endothelial cell proliferation inhibition, a major benefit in fighting vascular neointima formation. In addition, we identified the structural features of leoligin analogs that define their ability to inhibit the pro-inflammatory NF-κB pathway. Results are discussed in the context of structural modification of these novel synthetic lignans.