Cannabinoid CB2 receptor (CB2R) is a class A G protein-coupled receptor (GPCR) involved in a broad spectrum of physiological processes and pathological conditions. For that reason, targeting CB2R... Show moreCannabinoid CB2 receptor (CB2R) is a class A G protein-coupled receptor (GPCR) involved in a broad spectrum of physiological processes and pathological conditions. For that reason, targeting CB2R might provide therapeutic opportunities in neurodegenerative disorders, neuropathic pain, inflammatory diseases, and cancer. The main components from Cannabis sativa, such as Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD), have been therapeutically exploited and synthetically-derived analogs have been generated. One example is cannabidiol-dimethylheptyl (CBD-DMH), which exhibits anti-inflammatory effects. Nevertheless, its pharmacological mechanism of action is not yet fully understood and is hypothesized for multiple targets, including CB2R. The aim of this study was to further investigate the molecular pharmacology of CBD-DMH on CB2R while CBD was taken along as control. These compounds were screened in equilibrium and kinetic radioligand binding studies and various functional assays, including G protein activation, inhibition of cAMP production and ß-arrestin-2 recruitment. In dissociation studies, CBD-DMH allosterically modulated the radioligand binding. Furthermore, CBD-DMH negatively modulated the G protein activation of reference agonists CP55,940, AEA and 2-AG, but not the agonist-induced ß-arrestin-2 recruitment. Nevertheless, CBD-DMH also displayed competitive binding to CB2R and partial agonism on G protein activation, inhibition of cAMP production and ß-arrestin-2 recruitment. CBD did not exhibit such allosteric behavior and only very weakly bound CB2R without activation. This study shows a dual binding mode of CBD-DMH, but not CBD, to CB2R with the suggestion of two different binding sites. Altogether, it encourages further research into this dual mechanism which might provide a new class of molecules targeting CB2R. Show less
Background: Internationally recognized guidelines recommend the judicious use of low oxygen (21-30%), titrated to peripheral oxygen saturation targets, for the initiation of re- suscitation of very... Show moreBackground: Internationally recognized guidelines recommend the judicious use of low oxygen (21-30%), titrated to peripheral oxygen saturation targets, for the initiation of re- suscitation of very and extremely preterm infants (<32 weeks' gestation). However, despite more than 10 randomized controlled trials on this question, the ideal initial oxygen concentration for this group of vulnerable infants remains uncertain. Aims: This study aims to assess the effect of various initial oxygen concentrations on (1) all-cause mortality, chronic lung disease, intraventricular hemorrhage, and retinopathy of prematurity; and (2) reaching the prescribed oxygen saturation targets by 5 min after birth, in preterm infants requiring resuscitation. Methods: We will conduct a system- atic review and network meta-analysis using individual participant data. Studies of preterm infants <32 weeks' gestation, randomized to initial oxygen concentration, will be included. We will systematically search medical databases and trial registriesfor eligible studies (published or unpublished). Records will be screened by two independent reviewers, with conflicts resolved by the inclusion of a third reviewer. Identified initial oxygen concentrations will be grouped into the following nodes: low (<= 30%), intermediate (60%), and high (>= 90%) oxygen. A two-step random-effects contrastbased network meta-regression will be calculated to compare and rank different oxygen concentrations. Analyses will be intention-to-treat, with the primary outcome of all-cause mortality. Discussion: This is the first individual participant data network meta-analysis of initial oxygen concentrations for the resuscitation of preterm infants. This novel approach may address long-standing uncertainty regarding optimal oxygen supplementation practice for the resuscitation of preterm infants <32 weeks' gestation. (C) 2022 S. Karger AG, Basel Show less
Zurlo, E.; Passerini, L.; Kumar, P.; Huber, M. 2021
Self-aggregation of amyloid proteins is a crucial step in neurodegenerative disease. The protein alpha-synuclein (alpha S) is implicated in Parkinson's disease. In an extension of the demonstration... Show moreSelf-aggregation of amyloid proteins is a crucial step in neurodegenerative disease. The protein alpha-synuclein (alpha S) is implicated in Parkinson's disease. In an extension of the demonstration of in situ observation of intermediates in alpha S-aggregation by continuous wave (cw) EPR at room temperature (Zurlo et al. PLoS One 16: e0245548, 2021) by spin-label EPR, here the spin label is attached to position 90 (R1 alpha S90), rather than at position 56. The aim is to determine, if the spin-label position affects the kinetics of aggregation and if local information on the intermediates is accessible. Probed by the MTSL ((1-Oxyl-2,2,5,5-tetramethylpyrroline-3-methyl) methanethiosulfonate) spin label at position 90, using diamagnetic dilution of 9:1 wild type alpha S to R1 alpha S90, similar aggregation kinetics are found. Rotation correlation times for the spin label in the oligomer cannot be determined with sufficient accuracy to obtain local information on the oligomer under the conditions used. At the present stage, higher resolution EPR approaches, such as high-field EPR are more promising. Show less
The thesis describes the use of electron paramagnetic resonance (EPR) spectroscopy, in continuous wave and pulse modes, to address the interaction of α-Synuclein (αS) with membranes and the... Show moreThe thesis describes the use of electron paramagnetic resonance (EPR) spectroscopy, in continuous wave and pulse modes, to address the interaction of α-Synuclein (αS) with membranes and the aggregation of αS. The protein, αS, associated with Parkinson’s disease, plays its role by interacting with vesicles/membranes in nerve cells in the brain. We investigate, specifically, the interaction of αS with small unilamellar vesicles mimicking the inner mitochondrial membrane and the neuronal plasma membrane (chapter 2). Also, the influence of phosphorylation of αS at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding is investigated (chapter 3). One of the peculiar properties of αS is to form amyloid fibrils. In the fibril, the protein chain of αS is folded into a β-sheet structure. We investigate how αS is folded in the fibrils (chapter 4 and 5). The chapter 6 focuses on peptides that help in membrane fusion. Using two small helical peptides, K and E, which act as zippers in the membrane-fusion model, we investigate the orientation of K and E in the zipper. Show less
