Chemical Probes to Control and Visualize Lipid Metabolism in the Brain

CONSPECTUS: Signaling lipids, such as the endocannabinoids, play an important role in the brain. They regulate synaptic transmission and control various neurophysiological processes, including pain sensation, appetite, memory formation, stress, and anxiety. Unlike classical neurotransmitters, lipid messengers are produced on demand and degraded by metabolic enzymes to control their lifespan and signaling actions. Chemical biology approaches have become one of the main driving forces to study and unravel the physiological role of lipid messengers in the brain. Here, we review how the development and use of chemical probes has allowed one to study endocannabinoid signaling by (i) inhibiting the biosynthetic and metabolic enzymes; (ii) visualizing the activity of these enzymes; and (iii) controlling the release and transport of the endocannabinoids. Activity-based probes were instrumental to guide the discovery of highly selective and in vivo active inhibitors of the biosynthetic (DAGL, NAPE-PLD) and metabolic (MAGL, FAAH) enzymes of endocannabinoids. These inhibitors allowed one to study the role of these enzymes in animal models of disease. For instance, the DAGL-MAGL axis was shown to control neuroinflammation and the NAPE-PLD-FAAH axis to regulate emotional behavior. Activity-based protein profiling and chemical proteomics were essential to guide the drug discovery and development of compounds targeting MAGL and FAAH, such as ABX-1431 (Lu AG06466) and PF-04457845, respectively. These experimental drugs are now in clinical trials for multiple indications, including multiple sclerosis and post-traumatic stress disorders. Activity-based probes have also been used to visualize the activity of these lipid metabolizing enzymes with high spatial resolution in brain slices, thereby showing the cell type-specific activity of these lipid metabolizing enzymes. The transport, release, and uptake of signaling lipids themselves cannot, however, be captured by activity-based probes in a spatiotemporal controlled manner. Therefore, bio-orthogonal lipids equipped with photoreactive, photoswitchable groups or photocages have been developed. These chemical probes were employed to investigate the protein interaction partners of the endocannabinoids, such as putative membrane transporters, as well as to study the functional cellular responses within milliseconds upon irradiation. Finally, genetically encoded sensors have recently been developed to monitor the real-time release of endocannabinoids with high spatiotemporal resolution in cultured neurons, acute brain slices, and in vivo mouse models. It is anticipated that the combination of chemical probes, highly selective inhibitors, and sensors with advanced (super resolution) imaging modalities, such as PharmacoSTORM and correlative light-electron microscopy, will uncover the fundamental basis of lipid signaling at nanoscale resolution in the brain. Furthermore, chemical biology approaches enable the translation of these fundamental discoveries into clinical solutions for brain diseases with aberrant lipid signaling.Molecular Physiolog

CD1d-Invariant Natural Killer T Cell-Based Cancer Immunotherapy: α-Galactosylceramide and Beyond

CD1d-restricted invariant natural killer T (iNKT) cells are considered an attractive target for cancer immunotherapy. Upon their activation by glycolipid antigen and/or cytokines, iNKT cells can induce direct lysis of tumor cells but can also induce an antitumor immune response via their rapid production of proinflammatory cytokines that trigger the cytotoxic machinery of other components of the innate and adaptive immune system. Here, we provide an overview of various therapeutic approaches that have been evaluated or that are currently being developed and/or explored. These include administration of α-GalCer or alternative (glyco) lipid antigens, glycolipid-loaded antigen-presenting cells and liposomes, strategies that enhance CD1d expression levels or are based on ligation of CD1d, adoptive transfer of iNKT cells or chimeric antigen receptor iNKT cells, and tumor targeting of iNKT cells

Corrigendum: CD1d-Invariant Natural Killer T Cell-Based Cancer Immunotherapy: α-Galactosylceramide and Beyond

by King, L. A., Lameris, R., de Gruijl, T. D., and van der Vliet, H. J. (2018). Front. Immunol. 9:1519. doi: 10.3389/fimmu.2018.01519 In the original article, we neglected to disclose that authors Lisa A. King and Roeland Lameris are currently funded by Lava Therapeutics and that Hans J. van der Vliet also acts as chief scientific officer of Lava Therapeutics. Hans J. van der Vliet's affiliation has been updated to reflect this. The corrected Conflict of Interest statement appears below

Correlations of blood and brain biochemistry in phenylketonuria: results from the Pah-enu2 PKU mouse

Background: In phenylketonuria (PKU), treatment monitoring is based on frequent blood phenylalanine (Phe) measurements, as this is the predictor of neurocognitive and behavioural outcome by reflecting brain Phe con-centrations and brain biochemical changes. Despite clinical studies describing the relevance of blood Phe to out-come in PKU patients, blood Phe does not explain the variance in neurocognitive and behavioural outcome completely. Methods: In a PKU mouse model we investigated 1) the relationship between plasma Phe and brain biochemistry (Brain Phe and monoaminergic neurotransmitter concentrations), and 2) whether blood non-Phe Large Neutral Amino Acids (LNAA) would be of additional value to blood Phe concentrations to explain brain biochemistry. To this purpose, we assessed blood amino acid concentrations and brain Phe as well as monoaminergic neuro -transmitter levels in in 114 Pah-Enu2 mice on both B6 and BTBR backgrounds using (multiple) linear regression analyses. Results: Plasma Phe concentrations were strongly correlated to brain Phe concentrations, significantly negatively correlated to brain serotonin and norepinephrine concentrations and only weakly correlated to brain dopamine concentrations. From all blood markers, Phe showed the strongest correlation to brain biochemistry in PKU mice. Including non-Phe LNAA concentrations to the multiple regression model, in addition to plasma Phe, did not help explain brain biochemistry. Conclusion: This study showed that blood Phe is still the best amino acid predictor of brain biochemistry in PKU. Nevertheless, neurocognitive and behavioural outcome cannot fully be explained by blood or brain Phe concen-trations, necessitating a search for other additional parameters. Take-home message: Blood Phe is still the best amino acid predictor of brain biochemistry in PKU. Nevertheless, neurocognitive and behavioural outcome cannot fully be explained by blood or brain Phe concentrations, neces-sitating a search for other additional parameters. (c) 2021 Published by Elsevier Inc.Education and Child Studie

New food composition data on selected ethnic foods consumed in Europe

Background: Reliable data on the composition of foods is needed to better understand individual diets, measure nutrient intakes and provide nutritional guidance for improving the health of the populations. Ethnic foods are becoming increasingly popular among all European consumers, and are the main source of nutrients in the diets of ethnic groups. However, there is limited information on the nutrient composition of ethnic foods in Europe. The objective of this study therefore was to generate new and reliable data on ethnic foods using harmonised methods for chemical analyses. Methods: New data on 128 ethnic foods were generated for inclusion in the national databases within the European Food Information Resource Network of Excellence through participants from France, Israel, Spain, Denmark, Italy, The Netherlands, Belgium and the United Kingdom. In each selected country, the list of prioritised foods and key nutrients, methods of analyses and quality assurance procedure were harmonised. Results: This paper presents the nutrient composition of 40 ethnic foods consumed in Europe. The nutrient composition of the foods varied widely because of the nature and variety of foods analysed, with energy content (kcal) ranging between 24 (biteku-teku, Blegium) and 495 (nachos, Italy) per 100 g of edible food. Polyunsaturated and monounsaturated fatty acids were generally higher in most ethnic foods consumed in Italy and Spain compared with ethnic foods of other countries. Conclusions: The new data were scrutinised and fully documented for inclusion in the national food composition databases. The data will aid effective diet and disease interventions, and enhance the provision of dietary advice, in all European consumers

Lot-to-lot consistency of a tetravalent dengue vaccine in healthy adults in Australia: a randomised study

Background: The recombinant yellow fever-17D-dengue virus, live, attenuated, tetravalent dengue vac-cine (CYD-TDV) has undergone extensive clinical trials. Here safety and consistency of immunogenicityof phase III manufacturing lots of CYD-TDV were evaluated and compared with a phase II lot and placeboin a dengue-naïve population.Methods: Healthy 18–60 year-olds were randomly assigned in a 3:3:3:3:1 ratio to receive three sub-cutaneous doses of either CYD-TDV from any one of three phase III lots or a phase II lot, or placebo,respectively in a 0, 6, 12 month dosing schedule. Neutralising antibody geometric mean titres (PRNT50GMTs) for each of the four dengue serotypes were compared in sera collected 28 days after the thirdvaccination—equivalence among lots was demonstrated if the lower and upper limits of the two-sided95% CIs of the GMT ratio were ≥0.5 and ≤2.0, respectively.Results: 712 participants received vaccine or placebo and 614 (86%) completed the study; 17 (2.4%) par-ticipants withdrew after adverse events. Equivalence of phase III lots was demonstrated for 11 of 12pairwise comparisons. One of three comparisons for serotype 2 was not statistically equivalent. GMTsfor serotype 2 in phase III lots were close to each other (65.9, 44.1 and 58.1, respectively).Conclusions: Phase III lots can be produced in a consistent manner with predictable immune responseand acceptable safety profile similar to previously characterised phase II lots. The phase III lots maybe considered as not clinically different as statistical equivalence was shown for serotypes 1, 3 and 4across the phase III lots. For serotype 2, although equivalence was not shown between two lots, the GMTsobserved in the phase III lots were consistently higher than those for the phase II lot. As such, in our view,biological equivalence for all serotypes was demonstrated.Joseph Torresi, Leon G. Heron, Ming Qiao, Joanne Marjason, Laurent Chambonneau, Alain Bouckenooghe, Mark Boaz, Diane van der Vliet, Derek Wallace, Yanee Hutagalung, Michael D. Nissen, Peter C. Richmon

Lifestyle and clinical determinants of skin autofluorescence in a population-based cohort study

BACKGROUND: Skin autofluorescence (SAF) is a non-invasive marker of advanced glycation end products (AGEs). In diabetes, higher SAF levels has been positively associated with long-term complications, cardiovascular morbidity and mortality. Because little is known about the factors that influence SAF in non-diabetic individuals, we assessed the association of clinical and lifestyle parameters with SAF as well as their interactions in a large-scale, non-diabetic population and performed the same analyses in a type 2 diabetic subgroup. METHODS: In a cross-sectional study in participants from the LifeLines Cohort Study, extensive clinical and biochemical phenotyping, including SAF measurement, was assessed in 9009 subjects of whom 314 (3.5%) subjects with type 2 diabetes. RESULTS: Mean SAF was 2.04 ± 0.44 arbitrary units (AU) in non-diabetic individuals and 2.44 ± 0.55 AU in type 2 diabetic subjects (p<0.0001). Multivariate backward regression analysis showed that in the non-diabetic population, SAF was significantly and independently associated with age, BMI, HbA1c, creatinine clearance, genetic polymorphism in NAT2 (rs4921914), current smoking, pack-years of smoking and coffee consumption. In the type 2 diabetic group, a similar set of factors was associated with SAF, except for coffee consumption. CONCLUSIONS: In addition to the established literature on type 2 diabetes, we have demonstrated that SAF levels are associated with several clinical and lifestyle factors in the non-diabetic population. These parameters should be taken into consideration when using SAF as a screening or prediction tool for populations at risk for cardiovascular disease and diabetes. This article is protected by copyright. All rights reserved

Phase I-II study of everolimus and low-dose oral cyclophosphamide in patients with metastatic renal cell cancer

<p>Abstract</p> <p>Background</p> <p>For patients with metastatic renal cell cancer (mRCC) who progressed on vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor therapy, the orally administered mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to prolong progression free survival. Intriguingly, inhibition of mTOR also promotes expansion of immunosuppressive regulatory T cells (Tregs) that can inhibit anti-tumor immune responses in a clinically relevant way in various tumor types including RCC. This study intends to investigate whether the antitumor efficacy of everolimus can be increased by preventing the detrimental everolimus induced expansion of Tregs using a metronomic schedule of cyclophosphamide.</p> <p>Methods/design</p> <p>This phase I-II trial is a national multi-center study of different doses and schedules of low-dose oral cyclophosphamide in combination with a fixed dose of everolimus in patients with mRCC not amenable to or progressive after a VEGF-receptor tyrosine kinase inhibitor containing treatment regimen. In the phase I part of the study the optimal Treg-depleting dose and schedule of metronomic oral cyclophosphamide when given in combination with everolimus will be determined. In the phase II part of the study we will evaluate whether the percentage of patients progression free at 4 months of everolimus treatment can be increased from 50% to 70% by adding metronomic cyclophosphamide (in the dose and schedule determined in the phase I part). In addition to efficacy, we will perform extensive immune monitoring with a focus on the number, phenotype and function of Tregs, evaluate the safety and feasibility of the combination of everolimus and cyclophosphamide, perform monitoring of selected angiogenesis parameters and analyze everolimus and cyclophosphamide drug levels.</p> <p>Discussion</p> <p>This phase I-II study is designed to determine whether metronomic cyclophosphamide can be used to counter the mTOR inhibitor everolimus induced Treg expansion in patients with metastatic renal cell carcinoma and increase the antitumor efficacy of everolimus.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier <a href="http://www.clinicaltrials.gov/ct2/show/NCT01462214">NCT01462214</a>, EudraCT number 2010-024515-13, Netherlands Trial Register number <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2040">NTR3085</a>.</p