TY - JOUR A1 - Winkelbeiner, Nicola A1 - Wandt, Viktoria K. A1 - Ebert, Franziska A1 - Lossow, Kristina A1 - Bankoglu, Ezgi E. A1 - Martin, Maximilian A1 - Mangerich, Aswin A1 - Stopper, Helga A1 - Bornhorst, Julia A1 - Kipp, Anna P. A1 - Schwerdtle, Tanja T1 - A multi-endpoint approach to base excision repair incision activity augmented by PARylation and DNA damage levels in mice: impact of sex and age JF - International Journal of Molecular Sciences N2 - Investigation of processes that contribute to the maintenance of genomic stability is one crucial factor in the attempt to understand mechanisms that facilitate ageing. The DNA damage response (DDR) and DNA repair mechanisms are crucial to safeguard the integrity of DNA and to prevent accumulation of persistent DNA damage. Among them, base excision repair (BER) plays a decisive role. BER is the major repair pathway for small oxidative base modifications and apurinic/apyrimidinic (AP) sites. We established a highly sensitive non-radioactive assay to measure BER incision activity in murine liver samples. Incision activity can be assessed towards the three DNA lesions 8-oxo-2'-deoxyguanosine (8-oxodG), 5-hydroxy-2'-deoxyuracil (5-OHdU), and an AP site analogue. We applied the established assay to murine livers of adult and old mice of both sexes. Furthermore, poly(ADP-ribosyl)ation (PARylation) was assessed, which is an important determinant in DDR and BER. Additionally, DNA damage levels were measured to examine the overall damage levels. No impact of ageing on the investigated endpoints in liver tissue were found. However, animal sex seems to be a significant impact factor, as evident by sex-dependent alterations in all endpoints investigated. Moreover, our results revealed interrelationships between the investigated endpoints indicative for the synergetic mode of action of the cellular DNA integrity maintaining machinery. KW - maintenance of genomic integrity KW - ageing KW - sex KW - DNA damage KW - base excision repair (incision activity) KW - DNA damage response KW - poly(ADP-ribosyl)ation KW - liver Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285706 SN - 1422-0067 VL - 21 IS - 18 ER - TY - JOUR A1 - Paisdzior, Sarah A1 - Dimitriou, Ioanna Maria A1 - Schöpe, Paul Curtis A1 - Annibale, Paolo A1 - Scheerer, Patrick A1 - Krude, Heiko A1 - Lohse, Martin J. A1 - Biebermann, Heike A1 - Kühnen, Peter T1 - Differential signaling profiles of MC4R mutations with three different ligands JF - International Journal of Molecular Sciences N2 - The melanocortin 4 receptor (MC4R) is a key player in hypothalamic weight regulation and energy expenditure as part of the leptin–melanocortin pathway. Mutations in this G protein coupled receptor (GPCR) are the most common cause for monogenetic obesity, which appears to be mediated by changes in the anorectic action of MC4R via G\(_S\)-dependent cyclic adenosine-monophosphate (cAMP) signaling as well as other signaling pathways. To study potential bias in the effects of MC4R mutations between the different signaling pathways, we investigated three major MC4R mutations: a G\(_S\) loss-of-function (S127L) and a G\(_S\) gain-of-function mutant (H158R), as well as the most common European single nucleotide polymorphism (V103I). We tested signaling of all four major G protein families plus extracellular regulated kinase (ERK) phosphorylation and β-arrestin2 recruitment, using the two endogenous agonists, α- and β-melanocyte stimulating hormone (MSH), along with a synthetic peptide agonist (NDP-α-MSH). The S127L mutation led to a full loss-of-function in all investigated pathways, whereas V103I and H158R were clearly biased towards the G\(_{q/11}\) pathway when challenged with the endogenous ligands. These results show that MC4R mutations can cause vastly different changes in the various MC4R signaling pathways and highlight the importance of a comprehensive characterization of receptor mutations. KW - Melanocortin 4 receptor (MC4R) KW - Melanocyte stimulating hormones MSH KW - G protein coupled receptor (GPCR) KW - biased signaling Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285108 SN - 1422-0067 VL - 21 IS - 4 ER - TY - JOUR A1 - Obidiegwu, Jude E. A1 - Lyons, Jessica B. A1 - Chilaka, Cynthia A. T1 - The Dioscorea genus (yam) — an appraisal of nutritional and therapeutic potentials JF - Foods N2 - The quest for a food secure and safe world has led to continuous effort toward improvements of global food and health systems. While the developed countries seem to have these systems stabilized, some parts of the world still face enormous challenges. Yam (Dioscorea species) is an orphan crop, widely distributed globally; and has contributed enormously to food security especially in sub-Saharan Africa because of its role in providing nutritional benefits and income. Additionally, yam has non-nutritional components called bioactive compounds, which offer numerous health benefits ranging from prevention to treatment of degenerative diseases. Pharmaceutical application of diosgenin and dioscorin, among other compounds isolated from yam, has shown more prospects recently. Despite the benefits embedded in yam, reports on the nutritional and therapeutic potentials of yam have been fragmented and the diversity within the genus has led to much confusion. An overview of the nutritional and health importance of yam will harness the crop to meet its potential towards combating hunger and malnutrition, while improving global health. This review makes a conscious attempt to provide an overview regarding the nutritional, bioactive compositions and therapeutic potentials of yam diversity. Insights on how to increase its utilization for a greater impact are elucidated. KW - yam KW - Dioscorea KW - nutritional composition KW - bioactive compounds KW - therapeutic potential Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213102 SN - 2304-8158 VL - 9 IS - 9 ER - TY - JOUR A1 - Vazquez-Rodriguez, Saleta A1 - Vilar, Santiago A1 - Kachler, Sonja A1 - Klotz, Karl-Norbert A1 - Uriarte, Eugenio A1 - Borges, Fernanda A1 - Matos, Maria João T1 - Adenosine receptor ligands: coumarin−chalcone hybrids as modulating agents on the activity of hARs JF - Molecules N2 - Adenosine receptors (ARs) play an important role in neurological and psychiatric disorders such as Alzheimer's disease, Parkinson's disease, epilepsy and schizophrenia. The different subtypes of ARs and the knowledge on their densities and status are important for understanding the mechanisms underlying the pathogenesis of diseases and for developing new therapeutics. Looking for new scaffolds for selective AR ligands, coumarin–chalcone hybrids were synthesized (compounds 1–8) and screened in radioligand binding (hA\(_1\), hA\(_{2A}\) and hA\(_3\)) and adenylyl cyclase (hA\(_{2B}\)) assays in order to evaluate their affinity for the four human AR subtypes (hARs). Coumarin–chalcone hybrid has been established as a new scaffold suitable for the development of potent and selective ligands for hA\(_1\) or hA\(_3\) subtypes. In general, hydroxy-substituted hybrids showed some affinity for the hA\(_1\), while the methoxy counterparts were selective for the hA\(_3\). The most potent hA\(_1\) ligand was compound 7 (K\(_i\) = 17.7 µM), whereas compound 4 was the most potent ligand for hA\(_3\) (K\(_i\) = 2.49 µM). In addition, docking studies with hA\(_1\) and hA\(_3\) homology models were established to analyze the structure–function relationships. Results showed that the different residues located on the protein binding pocket could play an important role in ligand selectivity. KW - coumarin KW - chalcone KW - neurodegenerative diseases KW - adenosine receptors KW - binding affinity KW - docking Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213165 SN - 1420-3049 VL - 25 IS - 18 ER - TY - JOUR A1 - Jeanclos, Elisabeth A1 - Knobloch, Gunnar A1 - Hoffmann, Axel A1 - Fedorchenko, Oleg A1 - Odersky, Andrea A1 - Lamprecht, Anna‐Karina A1 - Schindelin, Hermann A1 - Gohla, Antje T1 - Ca\(^{2+}\) functions as a molecular switch that controls the mutually exclusive complex formation of pyridoxal phosphatase with CIB1 or calmodulin JF - FEBS Letters N2 - Pyridoxal 5′‐phosphate (PLP) is an essential cofactor for neurotransmitter metabolism. Pyridoxal phosphatase (PDXP) deficiency in mice increases PLP and γ‐aminobutyric acid levels in the brain, yet how PDXP is regulated is unclear. Here, we identify the Ca\(^{2+}\)‐ and integrin‐binding protein 1 (CIB1) as a PDXP interactor by yeast two‐hybrid screening and find a calmodulin (CaM)‐binding motif that overlaps with the PDXP‐CIB1 interaction site. Pulldown and crosslinking assays with purified proteins demonstrate that PDXP directly binds to CIB1 or CaM. CIB1 or CaM does not alter PDXP phosphatase activity. However, elevated Ca\(^{2+}\) concentrations promote CaM binding and, thereby, diminish CIB1 binding to PDXP, as both interactors bind in a mutually exclusive way. Hence, the PDXP‐CIB1 complex may functionally differ from the PDXP‐Ca\(^{2+}\)‐CaM complex. KW - calmodulin KW - chronophin KW - CIB1 KW - haloacid dehalogenase KW - pyridoxal phosphatase KW - vitamin B6 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-217963 VL - 594 IS - 13 SP - 2099 EP - 2115 ER - TY - JOUR A1 - Reimann, Hauke A1 - Stopper, Helga A1 - Hintzsche, Henning T1 - Long-term fate of etoposide-induced micronuclei and micronucleated cells in Hela-H2B-GFP cells JF - Archives of Toxicology N2 - Micronuclei are small nuclear cellular structures containing whole chromosomes or chromosomal fragments. While there is a lot of information available about the origin and formation of micronuclei, less is known about the fate of micronuclei and micronucleated cells. Possible fates include extrusion, degradation, reincorporation and persistence. Live cell imaging was performed to quantitatively analyse the fates of micronuclei and micronucleated cells occurring in vitro. Imaging was conducted for up to 96 h in HeLa-H2B-GFP cells treated with 0.5, 1 and 2 µg/ml etoposide. While a minority of micronuclei was reincorporated into the main nucleus during mitosis, the majority of micronuclei persisted without any alterations. Degradation and extrusion were observed rarely or never. The presence of micronuclei affected the proliferation of the daughter cells and also had an influence on cell death rates. Mitotic errors were found to be clearly increased in micronucleus-containing cells. The results show that micronuclei and micronucleated cells can, although delayed in cell cycle, sustain for multiple divisions. KW - micronuclei KW - cell fate KW - etoposide KW - live imaging KW - DNA damage Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235039 SN - 0340-5761 VL - 94 ER - TY - JOUR A1 - Frey, Anna A1 - Gassenmaier, Tobias A1 - Hofmann, Ulrich A1 - Schmitt, Dominik A1 - Fette, Georg A1 - Marx, Almuth A1 - Heterich, Sabine A1 - Boivin-Jahns, Valérie A1 - Ertl, Georg A1 - Bley, Thorsten A1 - Frantz, Stefan A1 - Jahns, Roland A1 - Störk, Stefan T1 - Coagulation factor XIII activity predicts left ventricular remodelling after acute myocardial infarction JF - ESC Heart Failure N2 - Aims Acute myocardial infarction (MI) is the major cause of chronic heart failure. The activity of blood coagulation factor XIII (FXIIIa) plays an important role in rodents as a healing factor after MI, whereas its role in healing and remodelling processes in humans remains unclear. We prospectively evaluated the relevance of FXIIIa after acute MI as a potential early prognostic marker for adequate healing. Methods and results This monocentric prospective cohort study investigated cardiac remodelling in patients with ST-elevation MI and followed them up for 1 year. Serum FXIIIa was serially assessed during the first 9 days after MI and after 2, 6, and 12 months. Cardiac magnetic resonance imaging was performed within 4 days after MI (Scan 1), after 7 to 9 days (Scan 2), and after 12 months (Scan 3). The FXIII valine-to-leucine (V34L) single-nucleotide polymorphism rs5985 was genotyped. One hundred forty-six patients were investigated (mean age 58 ± 11 years, 13% women). Median FXIIIa was 118 % (quartiles, 102–132%) and dropped to a trough on the second day after MI: 109%(98–109%; P < 0.001). FXIIIa recovered slowly over time, reaching the baseline level after 2 to 6 months and surpassed baseline levels only after 12 months: 124 % (110–142%). The development of FXIIIa after MI was independent of the genotype. FXIIIa on Day 2 was strongly and inversely associated with the relative size of MI in Scan 1 (Spearman’s ρ = –0.31; P = 0.01) and Scan 3 (ρ = –0.39; P < 0.01) and positively associated with left ventricular ejection fraction: ρ = 0.32 (P < 0.01) and ρ = 0.24 (P = 0.04), respectively. Conclusions FXIII activity after MI is highly dynamic, exhibiting a significant decline in the early healing period, with reconstitution 6 months later. Depressed FXIIIa early after MI predicted a greater size of MI and lower left ventricular ejection fraction after 1 year. The clinical relevance of these findings awaits to be tested in a randomized trial. KW - blood coagulation factor XIII KW - ST-elevation myocardial infarction KW - healing and remodelling processes KW - cardiac magnetic resonance imaging Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236013 VL - 7 IS - 5 ER - TY - JOUR A1 - Wölfel, Angela A1 - Sättele, Mathias A1 - Zechmeister, Christina A1 - Nikolaev, Viacheslov O. A1 - Lohse, Martin J. A1 - Boege, Fritz A1 - Jahns, Roland A1 - Boivin-Jahns, Valérie T1 - Unmasking features of the auto-epitope essential for β\(_1\)-adrenoceptor activation by autoantibodies in chronic heart failure JF - ESC Heart Failure N2 - Aims Chronic heart failure (CHF) can be caused by autoantibodies stimulating the heart via binding to first and/or second extracellular loops of cardiac β1-adrenoceptors. Allosteric receptor activation depends on conformational features of the autoantibody binding site. Elucidating these features will pave the way for the development of specific diagnostics and therapeutics. Our aim was (i) to fine-map the conformational epitope within the second extracellular loop of the human β\(_1\)-adrenoceptor (β1ECII) that is targeted by stimulating β\(_1\)-receptor (auto)antibodies and (ii) to generate competitive cyclopeptide inhibitors of allosteric receptor activation, which faithfully conserve the conformational auto-epitope. Methods and results Non-conserved amino acids within the β\(_1\)EC\(_{II}\) loop (compared with the amino acids constituting the ECII loop of the β\(_2\)-adrenoceptor) were one by one replaced with alanine; potential intra-loop disulfide bridges were probed by cysteine–serine exchanges. Effects on antibody binding and allosteric receptor activation were assessed (i) by (auto)antibody neutralization using cyclopeptides mimicking β1ECII ± the above replacements, and (ii) by (auto)antibody stimulation of human β\(_1\)-adrenoceptors bearing corresponding point mutations. With the use of stimulating β\(_1\)-receptor (auto)antibodies raised in mice, rats, or rabbits and isolated from exemplary dilated cardiomyopathy patients, our series of experiments unmasked two features of the β\(_1\)EC\(_{II}\) loop essential for (auto)antibody binding and allosteric receptor activation: (i) the NDPK\(^{211–214}\) motif and (ii) the intra-loop disulfide bond C\(^{209}\)↔C\(^{215}\). Of note, aberrant intra-loop disulfide bond C\(^{209}\)↔C\(^{216}\) almost fully disrupted the functional auto-epitope in cyclopeptides. Conclusions The conformational auto-epitope targeted by cardio-pathogenic β\(_1\)-receptor autoantibodies is faithfully conserved in cyclopeptide homologues of the β\(_1\)EC\(_{II}\) loop bearing the NDPK\(^{211–214}\) motif and the C\(^{209}\)↔C\(^{215}\) bridge while lacking cysteine C216. Such molecules provide promising tools for novel diagnostic and therapeutic approaches in β\(_1\)-autoantibodypositive CHF. KW - antibody/autoantibody KW - β1-adrenoceptor/β1-adrenergic receptor KW - chronic heart failure KW - conformational auto-epitope KW - cyclic peptides/cyclopeptides KW - cyclopeptide therapy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235974 VL - 7 IS - 4 ER - TY - JOUR A1 - Reimann, Hauke A1 - Stopper, Helga A1 - Polak, Thomas A1 - Lauer, Martin A1 - Herrmann, Martin J. A1 - Deckert, Jürgen A1 - Hintzsche, Henning T1 - Micronucleus frequency in buccal mucosa cells of patients with neurodegenerative diseases JF - Scientific Reports N2 - Neurodegenerative diseases show an increase in prevalence and incidence, with the most prominent example being Alzheimer's disease. DNA damage has been suggested to play a role in the pathogenesis, but the exact mechanisms remain elusive. We enrolled 425 participants with and without neurodegenerative diseases and analyzed DNA damage in the form of micronuclei in buccal mucosa samples. In addition, other parameters such as binucleated cells, karyolytic cells, and karyorrhectic cells were quantified. No relevant differences in DNA damage and cytotoxicity markers were observed in patients compared to healthy participants. Furthermore, other parameters such as lifestyle factors and diseases were also investigated. Overall, this study could not identify a direct link between changes in buccal cells and neurogenerative diseases, but highlights the influence of lifestyle factors and diseases on the human buccal cytome. KW - peripheral-blood lymphocytes KW - Alzheimers disease KW - DNA damage KW - cognitive impairment KW - cytome biomarkers KW - diagnosis KW - association KW - assay KW - life Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231430 VL - 10 ER - TY - JOUR A1 - Naseem, Muhammad A1 - Othman, Eman M. A1 - Fathy, Moustafa A1 - Iqbal, Jibran A1 - Howari, Fares M. A1 - AlRemeithi, Fatima A. A1 - Kodandaraman, Geema A1 - Stopper, Helga A1 - Bencurova, Elena A1 - Vlachakis, Dimitrios A1 - Dandekar, Thomas T1 - Integrated structural and functional analysis of the protective effects of kinetin against oxidative stress in mammalian cellular systems JF - Scientific Reports N2 - Metabolism and signaling of cytokinins was first established in plants, followed by cytokinin discoveries in all kingdoms of life. However, understanding of their role in mammalian cells is still scarce. Kinetin is a cytokinin that mitigates the effects of oxidative stress in mammalian cells. The effective concentrations of exogenously applied kinetin in invoking various cellular responses are not well standardized. Likewise, the metabolism of kinetin and its cellular targets within the mammalian cells are still not well studied. Applying vitality tests as well as comet assays under normal and hyper-oxidative states, our analysis suggests that kinetin concentrations of 500 nM and above cause cytotoxicity as well as genotoxicity in various cell types. However, concentrations below 100 nM do not cause any toxicity, rather in this range kinetin counteracts oxidative burst and cytotoxicity. We focus here on these effects. To get insights into the cellular targets of kinetin mediating these pro-survival functions and protective effects we applied structural and computational approaches on two previously testified targets for these effects. Our analysis deciphers vital residues in adenine phosphoribosyltransferase (APRT) and adenosine receptor (A2A-R) that facilitate the binding of kinetin to these two important human cellular proteins. We finally discuss how the therapeutic potential of kinetin against oxidative stress helps in various pathophysiological conditions. KW - cytokinins KW - 6-benzylaminopurine Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231317 VL - 10 ER -