Medizinische Chemie G-Protein-gekoppelter P2Y- und verwandter Waisen-Rezeptoren : Synthese, Optimierung und Charakterisierung selektiver Liganden als pharmakologische Tools

G-Protein-gekoppelte Rezeptoren (GPCRs) weisen eine große therapeutische Relevanz auf. Unter ihnen existieren auch sogenannte Waisen-Rezeptoren, deren endogener Ligand noch unbekannt ist. Im Hinblick auf die Entwicklung neuartiger Arzneistoffe wird diesen Rezeptoren ein besonders großes Potential zugeschrieben. Im Fokus dieser Arbeit standen vier phylogenetisch verwandte GPCRs, die der Rhodopsin-Gruppe angehören: der P2Y2-Rezeptor aus der Klasse der purinergen Rezeptoren und die drei Waisen-Rezeptoren GPR17, GPR35 und GPR84. Für diese wurden potente und selektive Liganden entwickelt. Aufgrund der (patho)physiologischen Funktionen des P2Y2-Rezeptors besitzen Antagonisten für diesen Rezeptor ein großes Potential zur Behandlung verschiedener Krankheiten. Jedoch sind derzeit kaum potente und selektive P2Y2-Rezeptor-Antagonisten in der Literatur beschrieben. Im Rahmen dieser Arbeit konnten 4-(Benzamido)benzensulfonsäurephenylester als Antagonisten mit IC50-Werten im niedrigen mikromolaren Bereich dargestellt werden. Sie waren selektiv sowohl gegenüber anderen P2Y-Rezeptorsubtypen als auch gegenüber Enzymen des purinergen Signaltransduktionswegs. Über die (patho)physiologische Rolle des proinflammatorischen Waisen-Rezeptors GPR84 ist nur wenig bekannt. Um seine Funktion besser untersuchen zu können, fehlen jedoch potente und selektive Antagonisten. Pranlukast (8-(4-(4-Phenylbutoxy)benzamido)-2-tetrazolylchromen-4-on), ein Antagonist des CysLT1-Rezeptors, inhibierte in einem internen Screening diesen Rezeptor im niedrigen mikromolaren Bereich. Wir haben daher Pranlukast als Leitstruktur für die Entwicklung potenter und selektiver GPR84-Antagonisten gewählt. Es wurde eine Bibliothek von über 80 Chromen-4-on-2-carbonsäure-Derivaten synthetisiert. Mithilfe von HPLC-MS-Untersuchungen konnte die hydrolytische Stabilität dieser Verbindungsklasse über einen weiten pH-Bereich gezeigt werden. In funktionellen cAMP-Akkumulationsexperimenten konnten Chromen-4-on-2-carbonsäure-Derivate als potente Antagonisten am humanen GPR84 mit IC50-Werten im nanomolaren Bereich identifiziert werden. Wir konnten damit die ersten in der Literatur beschriebenen GPR84-Antagonisten entwickeln. Im dritten Teilprojekt dieser Arbeit stand der Waisen-Rezeptor GPR35 im Mittelpunkt, über dessen (patho)physiologische Funktionen bisher noch wenig bekannt ist, auch weil bisher kaum hoch-potente und selektive GPR35-Agonisten existieren. In β-Arrestin-Rekrutierungsexperimenten wurde die Verbindung 8-Nitro-4-oxo-4H-chromen-2-carbonsäure als GPR35-Agonist mit moderater Wirksamkeit identifiziert. Sukzessive Optimierung dieser Struktur führte zur Verbindung 6-Brom-8-(4-methoxybenzamido)-4-oxo-4H-chromen-2-carbonsäure (PSB-13253), die zum Zeitpunkt der Veröffentlichung den potentesten Agonisten am humanen GPR35 darstellte (EC50 = 12,1 nM). Durch Tritiierung dieser Verbindung konnten wir den ersten in der Literatur beschriebenen GPR35-Radioliganden darstellen. Basierend auf den Ergebnissen der durchgeführten Radioligand-Bindungsstudien konnten neue Fluor-substituierte PSB-13253-Derivate entwickelt werden. Die Verbindung 6-Chlor-8-(2-fluor-4-methoxybenzamido)-4-oxo-4H-chromen-2-carbonsäure gehört mit einem EC50-Wert von 6,06 nM und einem Ki-Wert von 1,92 nM zu den potentesten und affinsten in der Literatur beschriebenen GPR35-Liganden. Die entwickelten GPR35-Agonisten sind selektiv gegenüber dem nah verwandten humanen GPR55 und den humanen Rezeptoren GPR17 und GPR84. Die hoch-potenten GPR35-Agonisten sowie der neue Radioligand stellen wertvolle pharmakologische Werkzeuge zur weiteren Erforschung des GPR35 dar

Overview of a planned flight test operation for a scaled in-air capturing demonstration

Current aerospace research seeks to realize reusable launch vehicle (RLV) missions. One conceptual idea is to capture a returning booster stage in air with another aircraft as proposed by DLR in previous work. Within the H2020 project - Formation flight for in-Air Launcher 1st stage Capturing demonstration (FALCon), we investigate the in-air-capturing (IAC) approach with a demonstration setup of scaled unmanned aerial vehicles to research different aspects of this approach in scaled flight tests. This paper provides an overview of the unmanned IAC demonstrators and the planned experiment setup of the FALCon project, which will be validated in future flight test demonstrations. We describe the details of three flight demonstrators for the reusable launch vehicle, capturing or towing aircraft, and an intelligent coupling device which we developed from scratch for this project. We focus on the safety aspects enabling the implementation of a safe and successful demonstration in a non-segregated European airspace and present our researched aspects of the IAC maneuver. The planned formation requires a relative pose estimation between the involved demonstrators, while the demonstrators perform a rapid unpowered descent. We use an environmental perception setup, based on camera and LiDAR data processing, to solve this challenging task

An international effort towards developing standards for best practices in analysis, interpretation and reporting of clinical genome sequencing results in the CLARITY Challenge

There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance. RESULTS: A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization. CONCLUSIONS: The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups

Enabling planetary science across light-years. Ariel Definition Study Report

Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution

Network Analyses Reveal Novel Aspects of ALS Pathogenesis

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by selective loss of motor neurons, muscle atrophy and paralysis. Mutations in the human VAMP-associated protein B (hVAPB) cause a heterogeneous group of motor neuron diseases including ALS8. Despite extensive research, the molecular mechanisms underlying ALS pathogenesis remain largely unknown. Genetic screens for key interactors of hVAPB activity in the intact nervous system, however, represent a fundamental approach towards understanding the in vivo function of hVAPB and its role in ALS pathogenesis. Targeted expression of the disease-causing allele leads to neurodegeneration and progressive decline in motor performance when expressed in the adult Drosophila, eye or in its entire nervous system, respectively. By using these two phenotypic readouts, we carried out a systematic survey of the Drosophila genome to identify modifiers of hVAPB-induced neurotoxicity. Modifiers cluster in a diverse array of biological functions including processes and genes that have been previously linked to hVAPB function, such as proteolysis and vesicular trafficking. In addition to established mechanisms, the screen identified endocytic trafficking and genes controlling proliferation and apoptosis as potent modifiers of ALS8-mediated defects. Surprisingly, the list of modifiers was mostly enriched for proteins linked to lipid droplet biogenesis and dynamics. Computational analysis reveals that most modifiers can be linked into a complex network of interacting genes, and that the human genes homologous to the Drosophila modifiers can be assembled into an interacting network largely overlapping with that in flies. Identity markers of the endocytic process were also found to abnormally accumulate in ALS patients, further supporting the relevance of the fly data for human biology. Collectively, these results not only lead to a better understanding of hVAPB function but also point to potentially relevant targets for therapeutic intervention

6‑Bromo-8-(4‑[³H]methoxybenzamido)-4-oxo‑4<i>H</i>‑chromene-2-carboxylic Acid: A Powerful Tool for Studying Orphan G Protein-Coupled Receptor GPR35

The potent and selective GPR35 agonist 6-bromo-8-(4-methoxybenzamido)-4-oxo-4<i>H</i>-chromene-2-carboxylic acid (<b>12</b>) was obtained in tritium-labeled form, designated [³H]­PSB-13253, with a specific activity of 36 Ci (1.33 TBq)/mmol. Radiolabeling was achieved by methylation of ethyl 6-bromo-8-(4-((<i>tert</i>-butyldimethylsilyl)­oxy)­benzamido)-4-oxo-4<i>H</i>-chromene-2-carboxylate (<b>19</b>) with [³H]­methyl tosylate followed by ester hydrolysis. The radioligand was characterized by kinetic, saturation, and competition assays at membrane preparations of Chinese hamster ovary cells recombinantly expressing the human GPR35. [³H]<b>12</b> labeled the receptor with high affinity (<i>K</i>_D = 5.27 nM). Binding was saturable (<i>B</i>_max = 12.6 pmol/mg of protein) and reversible. Affinities of selected standard ligands and a library of amidochromen-4-one-2-carboxylates were determined. Binding data mostly correlated with potencies determined in β-arrestin assays. On the basis of the test results, several new fluorine-substituted 6-bromo-8-benzamidochromen-4-one-2-carboxylic acids were obtained, which represent the most potent GPR35 agonists known to date. 6-Bromo-8-(2,6-difluoro-4-methoxybenzamido)-4-oxo-4<i>H</i>-chromene-2-carboxylic acid (<b>83</b>; <i>K</i>_i = 0.589 nM, EC₅₀ = 5.54 nM) showed the highest affinity with a <i>K</i>_i value in the subnanomolar range

An Improved Procedure for the Photoacylation of 1,4-Naphthoquinone with Aliphatic Aldehydes

Friedrichs F, Murphy B, Nayrat D, et al. An Improved Procedure for the Photoacylation of 1,4-Naphthoquinone with Aliphatic Aldehydes. SYNLETT. 2008;2008(20):3137-3140.Irradiation of 1,4-naphthoquinone at 300 25 rim in benzene and in the presence of aliphatic aldehydes readily yields acylated hydroquinones in good to high yields. The developed protocol represents a significant improvement over the original procedure using medium-pressure mercury lamps. Subsequent oxidation gives the corresponding acylated quinones