TY - JOUR A1 - Herrmann, Marietta A1 - Diederichs, Solvig A1 - Melnik, Svitlana A1 - Riegger, Jana A1 - Trivanović, Drenka A1 - Li, Shushan A1 - Jenei-Lanzl, Zsuzsa A1 - Brenner, Rolf E. A1 - Huber-Lang, Markus A1 - Zaucke, Frank A1 - Schildberg, Frank A. A1 - Grässel, Susanne T1 - Extracellular Vesicles in Musculoskeletal Pathologies and Regeneration JF - Frontiers in Bioengineering and Biotechnology N2 - The incidence of musculoskeletal diseases is steadily increasing with aging of the population. In the past years, extracellular vesicles (EVs) have gained attention in musculoskeletal research. EVs have been associated with various musculoskeletal pathologies as well as suggested as treatment option. EVs play a pivotal role in communication between cells and their environment. Thereby, the EV cargo is highly dependent on their cellular origin. In this review, we summarize putative mechanisms by which EVs can contribute to musculoskeletal tissue homeostasis, regeneration and disease, in particular matrix remodeling and mineralization, pro-angiogenic effects and immunomodulatory activities. Mesenchymal stromal cells (MSCs) present the most frequently used cell source for EV generation for musculoskeletal applications, and herein we discuss how the MSC phenotype can influence the cargo and thus the regenerative potential of EVs. Induced pluripotent stem cell-derived mesenchymal progenitor cells (iMPs) may overcome current limitations of MSCs, and iMP-derived EVs are discussed as an alternative strategy. In the last part of the article, we focus on therapeutic applications of EVs and discuss both practical considerations for EV production and the current state of EV-based therapies. KW - extracellular vesicles KW - exosomes KW - musculoskeletal diseases KW - MSC KW - iMP KW - cell-free therapeutics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222882 SN - 2296-4185 VL - 8 ER - TY - JOUR A1 - Dischinger, Ulrich A1 - Hasinger, Julia A1 - Königsrainer, Malina A1 - Corteville, Carolin A1 - Otto, Christoph A1 - Fassnacht, Martin A1 - Hankir, Mohamed A1 - Seyfried, Florian Johannes David T1 - Toward a Medical Gastric Bypass: Chronic Feeding Studies With Liraglutide + PYY\(_{3-36}\) Combination Therapy in Diet-Induced Obese Rats JF - Frontiers in Endocrinology N2 - Background Combination therapies of anorectic gut hormones partially mimic the beneficial effects of bariatric surgery. Thus far, the effects of a combined chronic systemic administration of Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine 3-36 (PYY\(_{3-36}\)) have not been directly compared to Roux-en-Y gastric bypass (RYGB) in a standardized experimental setting. Methods High-fat diet (HFD)-induced obese male Wistar rats were randomized into six treatment groups: (1) RYGB, (2) sham-operation (shams), (3) liraglutide, (4) PYY\(_{3-36}\), (5) PYY\(_{3-36}\)+liraglutide (6), saline. Animals were kept on a free choice high- and low-fat diet. Food intake, preference, and body weight were measured daily for 4 weeks. Open field (OP) and elevated plus maze (EPM) tests were performed. Results RYGB reduced food intake and achieved sustained weight loss. Combined PYY\(_{3-36}\)+liraglutide treatment led to similar and plateaued weight loss compared to RYGB. Combined PYY\(_{3-36}\)+liraglutide treatment was superior to PYY\(_{3-36}\) (p ≤ 0.0001) and liraglutide (p ≤ 0.05 or p ≤ 0.01) mono-therapy. PYY\(_{3-36}\)+liraglutide treatment and RYGB also reduced overall food intake and (less pronounced) high-fat preference compared to controls. The animals showed no signs of abnormal behavior in OF or EPM. Conclusions Liraglutide and PYY\(_{3-36}\) combination therapy vastly mimics reduced food intake, food choice and weight reducing benefits of RYGB. KW - obesity KW - rygb KW - liraglutide KW - peptide tyrosine tyrosine (PYY) KW - treatment KW - gastric bypass KW - peptide tyrosine tyrosine 3-36 (PYY3-36) Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223113 SN - 1664-2392 VL - 11 ER - TY - JOUR A1 - Oehler, Beatrice A1 - Brack, Alexander A1 - Blum, Robert A1 - Rittner, Heike L. T1 - Pain Control by Targeting Oxidized Phospholipids: Functions, Mechanisms, Perspectives JF - Frontiers in Endocrinology N2 - Within the lipidome oxidized phospholipids (OxPL) form a class of chemically highly reactive metabolites. OxPL are acutely produced in inflamed tissue and act as endogenous, proalgesic (pain-inducing) metabolites. They excite sensory, nociceptive neurons by activating transient receptor potential ion channels, specifically TRPA1 and TRPV1. Under inflammatory conditions, OxPL-mediated receptor potentials even potentiate the action potential firing rate of nociceptors. Targeting OxPL with D-4F, an apolipoprotein A-I mimetic peptide or antibodies like E06, specifically binding oxidized headgroups of phospholipids, can be used to control acute, inflammatory pain syndromes, at least in rodents. With a focus on proalgesic specificities of OxPL, this article discusses, how targeting defined substances of the epilipidome can contribute to mechanism-based therapies against primary and secondary chronic inflammatory or possibly also neuropathic pain. KW - oxidized phospholipids KW - TRP channel KW - ion channel KW - analgesia KW - pain therapy KW - nociception KW - therapeutic antibody KW - mimetic peptide Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223432 SN - 1664-2392 VL - 11 ER - TY - JOUR A1 - Würthner, Frank A1 - Noll, Niklas T1 - A Calix[4]arene‐Based Cyclic Dinuclear Ruthenium Complex for Light‐Driven Catalytic Water Oxidation JF - Chemistry - A European Journal N2 - A cyclic dinuclear ruthenium(bda) (bda: 2,2’‐bipyridine‐6,6’‐dicarboxylate) complex equipped with oligo(ethylene glycol)‐functionalized axial calix[4]arene ligands has been synthesized for homogenous catalytic water oxidation. This novel Ru(bda) macrocycle showed significantly increased catalytic activity in chemical and photocatalytic water oxidation compared to the archetype mononuclear reference [Ru(bda)(pic)\(_2\)]. Kinetic investigations, including kinetic isotope effect studies, disclosed a unimolecular water nucleophilic attack mechanism of this novel dinuclear water oxidation catalyst (WOC) under the involvement of the second coordination sphere. Photocatalytic water oxidation with this cyclic dinuclear Ru complex using [Ru(bpy)\(_3\)]Cl\(_2\) as a standard photosensitizer revealed a turnover frequency of 15.5 s\(^{−1}\) and a turnover number of 460. This so far highest photocatalytic performance reported for a Ru(bda) complex underlines the potential of this water‐soluble WOC for artificial photosynthesis. KW - water KW - oxidation KW - ruthenium KW - dinuclear KW - catalytic KW - artificial photosynthesis KW - homogenous catalysis KW - photocatalysis KW - ruthenium complexes KW - water oxidation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230030 UR - https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202004486 VL - 27 IS - 1 ER - TY - JOUR A1 - Würthner, Frank A1 - Meza-Chincha, Ana-Lucia A1 - Schindler, Dorothee A1 - Natali, Mirco T1 - Effects of Photosensitizers and Reaction Media on Light‐Driven Water Oxidation with Trinuclear Ruthenium Macrocycles JF - ChemPhotoChem N2 - Photocatalytic water oxidation is a promising process for the production of solar fuels and the elucidation of factors that influence this process is of high significance. Thus, we have studied in detail light‐driven water oxidation with a trinuclear Ru(bda) (bda: 2,2’‐bipyridine‐6,6’‐dicarboxylate) macrocycle MC3 and its highly water soluble derivative m‐CH\(_2\)NMe\(_2\)‐MC3 using a series of ruthenium tris(bipyridine) complexes as photosensitizers under varied reaction conditions. Our investigations showed that the catalytic activities of these Ru macrocycles are significantly affected by the choice of photosensitizer (PS) and reaction media, in addition to buffer concentration, light intensity and concentration of the sensitizer. Our steady‐state and transient spectroscopic studies revealed that the photocatalytic performance of trinuclear Ru(bda) macrocycles is not limited by their intrinsic catalytic activities but rather by the efficiency of photogeneration of oxidant PS\(^+\) and its ability to act as an oxidizing agent to the catalysts as both are strongly dependent on the choice of photosensitizer and the amount of employed organic co‐solvent. KW - photosenitizers KW - water oxidation KW - ruthenium complexes KW - macrocycles KW - trinuclear KW - homogenous catalysis KW - photocatalysis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230116 VL - 5 IS - 2 ER - TY - JOUR A1 - Kokic, Goran A1 - Hillen, Hauke S. A1 - Tegunov, Dimitry A1 - Dienermann, Christian A1 - Seitz, Florian A1 - Schmitzova, Jana A1 - Farnung, Lucas A1 - Siewert, Aaron A1 - Höbartner, Claudia A1 - Cramer, Patrick T1 - Mechanism of SARS-CoV-2 polymerase stalling by remdesivir JF - Nature Communications N2 - Remdesivir is the only FDA-approved drug for the treatment of COVID-19 patients. The active form of remdesivir acts as a nucleoside analog and inhibits the RNA-dependent RNA polymerase (RdRp) of coronaviruses including SARS-CoV-2. Remdesivir is incorporated by the RdRp into the growing RNA product and allows for addition of three more nucleotides before RNA synthesis stalls. Here we use synthetic RNA chemistry, biochemistry and cryoelectron microscopy to establish the molecular mechanism of remdesivir-induced RdRp stalling. We show that addition of the fourth nucleotide following remdesivir incorporation into the RNA product is impaired by a barrier to further RNA translocation. This translocation barrier causes retention of the RNA 3ʹ-nucleotide in the substrate-binding site of the RdRp and interferes with entry of the next nucleoside triphosphate, thereby stalling RdRp. In the structure of the remdesivir-stalled state, the 3ʹ-nucleotide of the RNA product is matched and located with the template base in the active center, and this may impair proofreading by the viral 3ʹ-exonuclease. These mechanistic insights should facilitate the quest for improved antivirals that target coronavirus replication. KW - SARS-CoV-2 polymerase KW - Remdesivir KW - RNA-dependent RNA polymerase KW - Molecular mechanism KW - Biochemistry KW - Cryoelectron microscopy KW - RNA Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-220979 VL - 12 ER -