To increase clinical success rate of drugs, a better understanding of drug action mechanism and disease dynamics is required. Metabolomics, which studies small molecules involved in biochemical... Show moreTo increase clinical success rate of drugs, a better understanding of drug action mechanism and disease dynamics is required. Metabolomics, which studies small molecules involved in biochemical processes in organisms, has shown to be a useful tool for this better understanding. In this thesis, we focus on the endocannabinoid system (ECS) and profiling its related metabolic pathways using liquid chromatography - mass spectrometry (LC-MS) based metabolomics techniques. The endocannabinoid system (ECS) is a signaling system involved in multiple physiological and pathological processes. Due to its wide distribution and complex network of metabolic interactions, the development of drugs targeting the ECS has seen high failure rates. To get a better understanding of the behavior of the ECS and related pathways, LC-MS platforms with wide coverage of the major ECS-related metabolites, or with high sensitivity that reaches low levels of metabolites, were developed and optimized. Furthermore, these metabolomics platforms were applied in clinical studies looking into cardiometabolic health, and revealed correlations between endogenous metabolite signaling, cardiometabolic health and the benefits of exercise. Show less
In this thesis, the discovery and optimization is described of chemical tools to study the N-acylethanolamine (NAE) biosynthetic pathway. In particular, two enzymes – N-acylphosphatidylethanolamine... Show moreIn this thesis, the discovery and optimization is described of chemical tools to study the N-acylethanolamine (NAE) biosynthetic pathway. In particular, two enzymes – N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) and phospholipase A and acyltransferase 2 (PLAAT2) – were targeted, which produce NAEs or their NAPE precursors, respectively. So far, genetic KO models have not been able to fully elucidate the complexity of NAE biosynthesis, possibly due to long-term compensatory effects. By blocking these enzymes in an acute fashion, the contributory role of NAPE-PLD and PLAAT2 with regard to NAE formation can be assessed across specific cells and tissues. To identify inhibitors for these enzymes, high throughput screening or focused-library screening approaches were applied. Using structure-activity relationship studies, initial hits were optimized to potent inhibitors, possessing cellular and/or in vivo efficacy. On-target confirmation was achieved by employing photoaffinity labeling or activity-based protein profiling. Cellular and/or in vivo activity of the described inhibitors was confirmed with targeted lipidomics experiments. To conclude, the herein developed NAPE-PLD and PLAAT2 inhibitors (LEI-401 and LEI-301, respectively) are suitable starting points to investigate the biological consequences of depleting the NAE tone, which may be useful in pathological conditions such as obesity, metabolic syndrome, chronic liver disease and cancer. Show less
Obesity has a great societal impact as it contributes to the development of type 2 diabetes and cardiovascular diseases. Activation of brown adipose tissue (BAT) is seen as a strategy to combat... Show moreObesity has a great societal impact as it contributes to the development of type 2 diabetes and cardiovascular diseases. Activation of brown adipose tissue (BAT) is seen as a strategy to combat adiposity and related disorders, because of its capacity to combust nutrients and increase energy expenditure. To develop novel BAT activating methods, a better understanding of the pathophysiology of diet-induced obesity on BAT function and whole-body metabolism is required. Studies described in this thesis have increased our understanding of nutrient handling by brown adipocytes. We also generated immortalized brown adipocytes which can be used for future research. Furthermore, we gained more insight into the development of diet-induced obesity; feeding a high fat diet (HFD) rapidly made BAT insulin resistant and less active. In addition, HFD feeding increased synthesis of so-called endocannabinoids in both white and brown adipose tissue. Because endocannabinoids regulate both energy intake and expenditure, future research should determine whether inhibiting endocannabinoid signaling specifically in adipose tissue is a worthwhile strategy to pursue in combating obesity. Finally, quercetin, which naturally occurs in fruits and vegetables, induced ‘browning’ of white adipose tissue and thereby improved blood lipid levels. These studies pave the road for further development of BAT-activating strategies! Show less
Background/ObjectivesEndocannabinoids (ECs) are associated with obesity and ectopic fat accumulation, both of which play a role in the development of cardiovascular disease (CVD) in type 2 diabetes... Show moreBackground/ObjectivesEndocannabinoids (ECs) are associated with obesity and ectopic fat accumulation, both of which play a role in the development of cardiovascular disease (CVD) in type 2 diabetes (T2D). The effect of prolonged caloric restriction on ECs in relation to fat distribution and cardiac function is still unknown. Therefore, our aim was to investigate this relationship in obese T2D patients with coronary artery disease (CAD).Subjects/MethodsIn a prospective intervention study, obese T2D patients with CAD (n = 27) followed a 16 week very low calorie diet (VLCD; 450–1000 kcal/day). Cardiac function and fat accumulation were assessed with MRI and spectroscopy. Plasma levels of lipid species, including ECs, were measured using liquid chromatography-mass spectrometry.ResultsVLCD decreased plasma levels of virtually all measured lipid species of the class of N-acylethanolamines including the EC anandamide (AEA; −15%, p = 0.016), without decreasing monoacylglycerols including the EC 2-arachidonoylglycerol (2-AG). Baseline plasma AEA levels strongly correlated with the volume of subcutaneous white adipose tissue (SAT; R2 = 0.44, p < 0.001). VLCD decreased the volume of SAT (−53%, p < 0.001), visceral white adipose tissue (VAT) (−52%, p < 0.001), epicardial white adipose tissue (−15%, p < 0.001) and paracardial white adipose tissue (−28%, p < 0.001). VLCD also decreased hepatic (−86%, p < 0.001) and myocardial (−33%, p < 0.001) fat content. These effects were accompanied by an increased left ventricular ejection fraction (54.8 ± 8.7–56.2 ± 7.9%, p = 0.016).ConclusionsCaloric restriction in T2D patients with CAD decreases AEA levels, but not 2-AG levels, which is paralleled by decreased lipid accumulation in adipose tissue, liver and heart, and improved cardiovascular function. Interestingly, baseline AEA levels strongly correlated with SAT volume. We anticipate that dietary interventions are worthwhile strategies in advanced T2D, and that reduction in AEA may contribute to the improved cardiometabolic phenotype induced by weight loss. Show less
Endocannabinoids, a class of lipid messengers, have emerged as crucial regulators of synaptic communication in the central nervous system (CNS). Dysregulation of these compounds has been... Show moreEndocannabinoids, a class of lipid messengers, have emerged as crucial regulators of synaptic communication in the central nervous system (CNS). Dysregulation of these compounds has been implicated in many brain disorders. Although some studies have identified and quantified a limited number of target compounds, a method that provides comprehensive quantitative information on endocannabinoids and related N-acylethanolamines (NAEs) in CSF is currently lacking as measurements are challenging due to low concentrations under normal physiological conditions. Here we developed and validated a high-throughput nano liquid chromatography-electrospray ionization mass spectrometry (nano LC-ESI-MS/MS) platform for the simultaneous quantification of endocannabinoids (anandamide (AEA), 2-arachidonoyl glycerol (2-AG)), ten related NAEs and eight additional putatively annotated NAEs in human CSF. Requiring only 200 μL of CSF our method has limits of detection from 0.28 to 61.2 pM with precisions of RSD <15% for most compounds. We applied our method to CSF from 45 healthy humans and demonstrated potential age and gender effects on concentrations of endocannabinoids and NAEs. Notably, our results show that docosahexaenoyl ethanolamide (DHEA) concentrations increase with age in males. Our method may offer new opportunities to gain insight into regulatory functions of endocannabinoids in the context of (ab)normal brain function. Show less
This Thesis reports on the discovery and optimization of potent inhibitors for the serine hydrolases sn-1 diacylglycerol lipase α (DAGLα) and α/β hydrolase domain 16A (ABHD16A). Several... Show more This Thesis reports on the discovery and optimization of potent inhibitors for the serine hydrolases sn-1 diacylglycerol lipase α (DAGLα) and α/β hydrolase domain 16A (ABHD16A). Several structure- and ligand-based drug discovery methodologies were employed, such as in silico screening and high throughput screening, in combination with activity-based protein profiling (ABPP). The glycine sulfonamides reported in this Thesis, such as LEI106, are important peripherally restricted inhibitors that can be used to evaluate the contribution of perturbing DAGL activity in the potential treatment of metabolic syndrome, diabetes and pheriphiral obesity. The α-keto heterocycles in this Thesis, such as LEI107, could be important inhibitors to evaluate if a therapeutic window can be established for (central) DAGL inhibitors in the potential treatment of addiction, obesity and neuroinflammation. Lastly, 1,2,4-triazole urea sulfonamides that are reported in this Thesis can be used as novel tool compounds to evaluate DAGL and ABHD16A function in both health and disease. Show less
