@article{BalasubramanianSkafHolzgrabeetal.2018, author = {Balasubramanian, Srikkanth and Skaf, Joseph and Holzgrabe, Ulrike and Bharti, Richa and F{\"o}rstner, Konrad U. and Ziebuhr, Wilma and Humeida, Ute H. and Abdelmohsen, Usama R. and Oelschlaeger, Tobias A.}, title = {A new bioactive compound from the marine sponge-derived Streptomyces sp. SBT348 inhibits staphylococcal growth and biofilm formation}, series = {Frontiers in Microbiology}, volume = {9}, journal = {Frontiers in Microbiology}, doi = {10.3389/fmicb.2018.01473}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221408}, year = {2018}, abstract = {Staphylococcus epidermidis, the common inhabitant of human skin and mucosal surfaces has emerged as an important pathogen in patients carrying surgical implants and medical devices. Entering the body via surgical sites and colonizing the medical devices through formation of multi-layered biofilms leads to refractory and persistent device-related infections (DRIs). Staphylococci organized in biofilms are more tolerant to antibiotics and immune responses, and thus are difficult-to-treat. The consequent morbidity and mortality, and economic losses in health care systems has strongly necessitated the need for development of new anti-bacterial and anti-biofilm-based therapeutics. In this study, we describe the biological activity of a marine sponge-derived Streptomyces sp. SBT348 extract in restraining staphylococcal growth and biofilm formation on polystyrene, glass, medically relevant titan metal, and silicone surfaces. A bioassay-guided fractionation was performed to isolate the active compound (SKC3) from the crude SBT348 extract. Our results demonstrated that SKC3 effectively inhibits the growth (MIC: 31.25 \(\mu\)g/ml) and biofilm formation (sub-MIC range: 1.95-<31.25 \(\mu\)g/ml) of S. epidermidis RP62A in vitro. Chemical characterization of SKC3 by heat and enzyme treatments, and mass spectrometry (HRMS) revealed its heat-stable and non-proteinaceous nature, and high molecular weight (1258.3 Da). Cytotoxicity profiling of SKC3 in vitro on mouse fibroblast (NIH/3T3) and macrophage (J774.1) cell lines, and in vivo on the greater wax moth larvae Galleria mellonella revealed its non-toxic nature at the effective dose. Transcriptome analysis of SKC3 treated S. epidermidis RP62A has further unmasked its negative effect on central metabolism such as carbon flux as well as, amino acid, lipid, and energy metabolism. Taken together, these findings suggest a potential of SKC3 as a putative drug to prevent staphylococcal DRIs.}, language = {en} } @article{SealSchwabChiarollaetal.2023, author = {Seal, Rishav and Schwab, Lara S. U. and Chiarolla, Cristina M. and Hundhausen, Nadine and Klose, Georg Heinrich and Reu-Hofer, Simone and Rosenwald, Andreas and Wiest, Johannes and Berberich-Siebelt, Friederike}, title = {Delayed and limited administration of the JAKinib tofacitinib mitigates chronic DSS-induced colitis}, series = {Frontiers in Immunology}, volume = {14}, journal = {Frontiers in Immunology}, doi = {10.3389/fimmu.2023.1179311}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-317815}, year = {2023}, abstract = {In inflammatory bowel disease, dysregulated T cells express pro-inflammatory cytokines. Using a chronic azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis model resembling ulcerative colitis, we evaluated whether and when treatment with the Janus kinase (JAK) inhibitor tofacitinib could be curative. Comparing the treatment with two and three cycles of tofacitinib medication in drinking water - intermittently with DSS induction - revealed that two cycles were not only sufficient but also superior over the 3-x regimen. The two cycles of the 2-x protocol paralleled the second and third cycles of the longer protocol. T cells were less able to express interferon gamma (IFN-γ) and the serum levels of IFN-γ, interleukin (IL)-2, IL-6, IL-17, and tumor necrosis factor (TNF) were significantly reduced in sera, while those of IL-10 and IL-22 increased under the 2-x protocol. Likewise, the frequency and effector phenotype of regulatory T cells (Tregs) increased. This was accompanied by normal weight gain, controlled clinical scores, and restored stool consistency. The general and histologic appearance of the colons revealed healing and tissue intactness. Importantly, two phases of tofacitinib medication completely prevented AOM-incited pseudopolyps and the hyper-proliferation of epithelia, which was in contrast to the 3-x regimen. This implies that the initial IBD-induced cytokine expression is not necessarily harmful as long as inflammatory signaling can later be suppressed and that time-restricted treatment allows for anti-inflammatory and tissue-healing cytokine activities.}, language = {en} } @article{WillemsDettaBaldinietal.2024, author = {Willems, Suzanne and Detta, Elena and Baldini, Lorenzo and Tietz, Deniz and Trabocchi, Andrea and Brunschweiger, Andreas}, title = {Diversifying DNA-tagged amines by isocyanide multicomponent reactions for DNA-encoded library synthesis}, series = {ACS Omega}, volume = {9}, journal = {ACS Omega}, number = {7}, issn = {2470-1343}, doi = {10.1021/acsomega.3c07136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349809}, pages = {7719-7724}, year = {2024}, abstract = {In DNA-encoded library synthesis, amine-substituted building blocks are prevalent. We explored isocyanide multicomponent reactions to diversify DNA-tagged amines and reported the Ugi-azide reaction with high yields and a good substrate scope. In addition, the Ugi-aza-Wittig reaction and the Ugi-4-center-3-component reaction, which used bifunctional carboxylic acids to provide lactams, were explored. Five-, six-, and seven-membered lactams were synthesized from solid support-coupled DNA-tagged amines and bifunctional building blocks, providing access to structurally diverse scaffolds.}, language = {en} } @article{SchmidtHolzgrabe2024, author = {Schmidt, Sebastian and Holzgrabe, Ulrike}, title = {Do the enantiomers of ketamine bind enantioselectively to human serum albumin?}, series = {European Journal of Pharmaceutical Sciences}, volume = {192}, journal = {European Journal of Pharmaceutical Sciences}, doi = {10.1016/j.ejps.2023.106640}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349791}, year = {2024}, abstract = {The binding of drugs to plasma proteins is an important process in the human body and has a significant influence on pharmacokinetic parameter. Human serum albumin (HSA) has the most important function as a transporter protein. The binding of ketamine to HSA has already been described in literature, but only of the racemate. The enantiomerically pure S-ketamine is used as injection solution for induction of anesthesia and has been approved by the Food and Drug Administration for the therapy of severe depression as a nasal spray in 2019. The question arises if there is enantioselective binding to HSA. Hence, the aim of this study was to investigate whether there is enantioselective binding of S-and R-ketamine to HSA or not. Ultrafiltration (UF) followed by chiral capillary electrophoretic analysis was used to determine the extent of protein binding. Bound fraction to HSA was 71.2 \% and 64.9 \% for enantiomerically pure R- and S-ketamine, respectively, and 66.5 \% for the racemate. Detailed binding properties were studied by Saturation Transfer Difference (STD)-, waterLOGSY- and Carr-Purcell-Meiboom-Gill (CPMG)-NMR spectroscopy. With all three methods, the aromatic ring and the N-methyl group could be identified as the structural moieties most strongly involved in binding of ketamine to HSA. pK\(_{aff}\) values determined using UF and NMR indicate that ketamine is a weak affinity ligand to HSA and no significant differences in binding behavior were found between the individual enantiomers and the racemate.}, language = {en} } @article{ScheupleinLohrVivoliVegaetal.2023, author = {Scheuplein, Nicolas Julian and Lohr, Theresa and Vivoli Vega, Mirella and Ankrett, Dyan and Seufert, Florian and Kirchner, Lukas and Harmer, Nicholas J. and Holzgrabe, Ulrike}, title = {Fluorescent probe for the identification of potent inhibitors of the macrophage infectivity potentiator (Mip) protein of Burkholderia pseudomallei}, series = {SLAS Discovery}, volume = {28}, journal = {SLAS Discovery}, number = {5}, doi = {10.1016/j.slasd.2023.03.004}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349784}, pages = {211-222}, year = {2023}, abstract = {Highlights • Synthesis of a new tracer molecule. • Robust and easy screening method for a broad range of compound activities. • FP assay validation considering limited use of starting material, DMSO tolerance, variation in incubation time and temperature. • Possibility of extension to HTP assay. Abstract The macrophage infectivity potentiator (Mip) protein belongs to the immunophilin superfamily. This class of enzymes catalyzes the interconversion between the cis and trans configuration of proline-containing peptide bonds. Mip has been shown to be important for the virulence of a wide range of pathogenic microorganisms, including the Gram-negative bacterium Burkholderia pseudomallei. Small molecules derived from the natural product rapamycin, lacking its immunosuppression-inducing moiety, inhibit Mip's peptidyl-prolyl cis-trans isomerase (PPIase) activity and lead to a reduction in pathogen load in vitro. Here, a fluorescence polarization assay (FPA) to enable the screening and effective development of BpMip inhibitors was established. A fluorescent probe was prepared, derived from previous pipecolic scaffold Mip inhibitors labeled with fluorescein. This probe showed moderate affinity for BpMip and enabled a highly robust FPA suitable for screening large compound libraries with medium- to high-throughput (Z factor ∼ 0.89) to identify potent new inhibitors. The FPA results are consistent with data from the protease-coupled PPIase assay. Analysis of the temperature dependence of the probe's binding highlighted that BpMip's ligand binding is driven by enthalpic rather than entropic effects. This has considerable consequences for the use of low-temperature kinetic assays.}, language = {en} } @article{TriyasmonoSchollmayerSchmitzetal.2023, author = {Triyasmono, Liling and Schollmayer, Curd and Schmitz, Jens and Hovah, Emilie and Lombo, Cristian and Schmidt, Sebastian and Holzgrabe, Ulrike}, title = {Simultaneous determination of the saponification value, acid value, ester value, and iodine value in commercially available red fruit oil (Pandanus conoideus, Lam.) using \(^1\)H qNMR spectroscopy}, series = {Food Analytical Methods}, volume = {16}, journal = {Food Analytical Methods}, number = {1}, issn = {1936-9751}, doi = {10.1007/s12161-022-02401-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324728}, pages = {155-167}, year = {2023}, abstract = {Red fruit oil (RFO) can be extracted from fruits of Pandanus conoideus, Lam., an endogenous plant of Papua, Indonesia. It is a commonly used essential original traditional medicine. By applying a newly developed quantitative \(^1\)H NMR (qNMR) spectroscopy method for quality assessment, a simultaneous determination of the saponification value (SV), acid value (AV), ester value (EV), and iodine value (IV) in RFO was possible. Dimethyl sulfone (DMSO\(_2\)) was used as an internal standard. Optimization of NMR parameters, such as NMR pulse sequence, relaxation delay time, and receiver gain, finally established the \(^1\)H NMR-based quantification approach. Diagnostic signals of the internal standard at δ = 2.98 ppm, SV at δ = 2.37-2.20 ppm, AV at δ = 2.27-2.20 ppm, EV at δ = 2.37-2.27 ppm, and IV at δ = 5.37-5.27 ppm, respectively, were used for quantitative analysis. The method was validated concerning linearity (R\(^2\) = 0.999), precision (less than 0.83\%), and repeatability in the range 99.17-101.17\%. Furthermore, this method was successfully applied to crude RFO, crude RFO with palmitic and oleic acid addition, and nine commercial products. The qNMR results for the respective fat values are in accordance with the results of standard methods, as can be seen from the F- and t-test (< 1.65 and < 1.66, respectively). The fundamental advantages of qNMR, such as its rapidity and simplicity, make it a feasible and existing alternative to titration for the quality control of RFO.}, language = {en} } @article{SchmidtHolzgrabe2023, author = {Schmidt, Sebastian and Holzgrabe, Ulrike}, title = {Method development, optimization, and validation of the separation of ketamine enantiomers by capillary electrophoresis using design of experiments}, series = {Chromatographia}, volume = {86}, journal = {Chromatographia}, number = {1}, issn = {0009-5893}, doi = {10.1007/s10337-022-04229-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324713}, pages = {87-95}, year = {2023}, abstract = {Capillary electrophoresis was chosen as cost-effective and robust method to separate ketamine enantiomers. For the method development, first different native and modified cyclodextrins were tested. The most promising chiral selector was α-cyclodextrin. A design of experiments (DoE) was carried out, which started with the screening of relevant factors. Based on these results, the method was optimized according to the significant factors (buffer, cyclodextrin concentration, pH value, voltage, temperature) of the screening based on the response resolution and migration time of the later migrating enantiomer. The optimized conditions consisted of a background electrolyte with 275 mM TRIS, adjusted with 85\% phosphoric acid to a pH of 2.50, and 50 mM α-cyclodextrin, at a temperature of 15 °C, an applied voltage of 30 kV and an injection pressure of 1.0 psi for 10 s. A fused-silica capillary with a total length of 70 cm and an effective length to the detector of 60 cm was used. The method was validated according to ICH guideline Q2 R(1). The limit of quantification was 3.51 µg mL\(^{-1}\) for S-ketamine and 3.98 µg mL\(^{-1}\)for R-ketamine. The method showed good linearity for racemic ketamine with R\(^2\) of 0.9995 for S-ketamine and 0.9994 for R-ketamine. The lowest quantifiable content of S-ketamine found in R-ketamine was 0.45\%.}, language = {en} } @article{WaltherKrmarLeistneretal.2023, author = {Walther, Rasmus and Krmar, Jovana and Leistner, Adrian and Svrkota, Bojana and Otašević, Biljana and Malenović, Andjelija and Holzgrabe, Ulrike and Protić, Ana}, title = {Analytical Quality by Design: achieving robustness of an LC-CAD method for the analysis of non-volatile fatty acids}, series = {Pharmaceuticals}, volume = {16}, journal = {Pharmaceuticals}, number = {4}, issn = {1424-8247}, doi = {10.3390/ph16040478}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311265}, year = {2023}, abstract = {An alternative to the time-consuming and error-prone pharmacopoeial gas chromatography method for the analysis of fatty acids (FAs) is urgently needed. The objective was therefore to propose a robust liquid chromatography method with charged aerosol detection for the analysis of polysorbate 80 (PS80) and magnesium stearate. FAs with different numbers of carbon atoms in the chain necessitated the use of a gradient method with a Hypersil Gold C\(_{18}\) column and acetonitrile as organic modifier. The risk-based Analytical Quality by Design approach was applied to define the Method Operable Design Region (MODR). Formic acid concentration, initial and final percentages of acetonitrile, gradient elution time, column temperature, and mobile phase flow rate were identified as critical method parameters (CMPs). The initial and final percentages of acetonitrile were fixed while the remaining CMPs were fine-tuned using response surface methodology. Critical method attributes included the baseline separation of adjacent peaks (α-linolenic and myristic acid, and oleic and petroselinic acid) and the retention factor of the last compound eluted, stearic acid. The MODR was calculated by Monte Carlo simulations with a probability equal or greater than 90\%. Finally, the column temperature was set at 33 °C, the flow rate was 0.575 mL/min, and acetonitrile linearly increased from 70 to 80\% (v/v) within 14.2 min.}, language = {en} } @article{MateraKaukCirilloetal.2023, author = {Matera, Carlo and Kauk, Michael and Cirillo, Davide and Maspero, Marco and Papotto, Claudio and Volpato, Daniela and Holzgrabe, Ulrike and De Amici, Marco and Hoffmann, Carsten and Dallanoce, Clelia}, title = {Novel Xanomeline-containing bitopic ligands of muscarinic acetylcholine receptors: design, synthesis and FRET investigation}, series = {Molecules}, volume = {28}, journal = {Molecules}, number = {5}, issn = {1420-3049}, doi = {10.3390/molecules28052407}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311249}, year = {2023}, abstract = {In the last few years, fluorescence resonance energy transfer (FRET) receptor sensors have contributed to the understanding of GPCR ligand binding and functional activation. FRET sensors based on muscarinic acetylcholine receptors (mAChRs) have been employed to study dual-steric ligands, allowing for the detection of different kinetics and distinguishing between partial, full, and super agonism. Herein, we report the synthesis of the two series of bitopic ligands, 12-Cn and 13-Cn, and their pharmacological investigation at the M\(_1\), M\(_2\), M\(_4\), and M\(_5\) FRET-based receptor sensors. The hybrids were prepared by merging the pharmacophoric moieties of the M\(_1\)/M\(_4\)-preferring orthosteric agonist Xanomeline 10 and the M\(_1\)-selective positive allosteric modulator 77-LH-28-1 (1-[3-(4-butyl-1-piperidinyl)propyl]-3,4-dihydro-2(1H)-quinolinone) 11. The two pharmacophores were connected through alkylene chains of different lengths (C3, C5, C7, and C9). Analyzing the FRET responses, the tertiary amine compounds 12-C5, 12-C7, and 12-C9 evidenced a selective activation of M\(_1\) mAChRs, while the methyl tetrahydropyridinium salts 13-C5, 13-C7, and 13-C9 showed a degree of selectivity for M\(_1\) and M\(_4\) mAChRs. Moreover, whereas hybrids 12-Cn showed an almost linear response at the M\(_1\) subtype, hybrids 13-Cn evidenced a bell-shaped activation response. This different activation pattern suggests that the positive charge anchoring the compound 13-Cn to the orthosteric site ensues a degree of receptor activation depending on the linker length, which induces a graded conformational interference with the binding pocket closure. These bitopic derivatives represent novel pharmacological tools for a better understanding of ligand-receptor interactions at a molecular level.}, language = {en} } @article{StraubVollmerLametal.2022, author = {Straub, Anton and Vollmer, Andreas and L{\^a}m, Thi{\^e}n-Tr{\´i} and Brands, Roman C. and Stapf, Maximilian and Scherf-Clavel, Oliver and Bittrich, Max and Fuchs, Andreas and K{\"u}bler, Alexander C. and Hartmann, Stefan}, title = {Evaluation of advanced platelet-rich fibrin (PRF) as a bio-carrier for ampicillin/sulbactam}, series = {Clinical Oral Investigations}, volume = {26}, journal = {Clinical Oral Investigations}, number = {12}, doi = {10.1007/s00784-022-04663-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324515}, pages = {7033-7044}, year = {2022}, abstract = {Objectives Mechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early surgical intervention is indicated. However, surgery often faces complications such as wound healing disorders. The application of platelet-rich fibrin (PRF) after necrosectomy between bone and mucosa may constitute a promising approach to improve surgical results. An aspect that was not investigated until now is that PRF acts as a "bio-carrier" for antibiotics previously applied intravenously. Materials and methods We investigated the antimicrobial properties of PRF in 24 patients presenting ONJ undergoing systemic antibiosis with ampicillin/sulbactam. We measured the concentration of ampicillin/sulbactam in plasma and PRF and performed agar diffusion tests. Ampicillin/sulbactam was applied intravenously to the patient 10 minutes for blood sampling for PRF. No further incorporation of patients' blood or PRF product with antibiotic drugs was obtained. Four healthy patients served as controls. Results Our results revealed that PRF is highly enriched with ampicillin/sulbactam that is released to the environment. The antibiotic concentration in PRF was comparable to the plasma concentration of ampicillin/sulbactam. The inhibition zone (IZ) of PRF was comparable to the standard ampicillin/sulbactam discs used in sensitivity testing. Conclusions The results of our study demonstrated that PRF is a reliable bio-carrier for systemic applied antibiotics and exhibits a large antimicrobial effect. Clinical relevance We describe a clinically useful feature of PRF as a bio-carrier for antibiotics. Especially when applied to poorly perfused tissues and bone such as in ONJ, the local release of antibiotics can reduce wound healing disorders like infections.}, language = {en} }