• Stereoselective Synthesis of a Protected Side Chain of Meliponamycin A.

      Andler, Oliver; Kazmaier, Uli; Organic Chemistry I, Saarland University, Campus Building C4.2, D-66123 Saarbrücken, GermanyHelmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University, Campus Building C8.1, D-66123 Saarbrücken, Germany (ACS/ American Chemical Society, 2023-03-28)
      The Matteson homologation was found to be a versatile tool for the construction of the linear polyketide side chain of meliponamycin and related compounds in only four steps. The ester dienolate version of this reaction allowed the introduction of the unsaturated ester moiety in a highly stereoselective fashion. Boronate oxidation/deoxygenation and Sharpless dihydroxylation are additional key steps in the stereoselective construction of this highly functionalized tetrahydropyran ring system, which is characteristic of this substance class
    • Structure-Guided Optimization of Small-Molecule Folate Uptake Inhibitors Targeting the Energy-Coupling Factor Transporters

      Kiefer, Alexander F.; Bousis, Spyridon; Hamed, Mostafa M.; Diamanti, Eleonora; Haupenthal, Jörg; Hirsch, Anna K.H.; a Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8.1, Saarbrücken, 66123, Germany b Department of Pharmacy, Saarland University, Campus E8.1, Saarbrücken, 66123, Germany c Helmholtz International Lab for Anti-Infectives, Campus E8.1, Saarbrücken, 66123, Germany (ACS/ American Chemical Society, 2022-07-14)
      Here, we report on a potent class of substituted ureidothiophenes targeting energy-coupling factor (ECF) transporters, an unexplored target that is not addressed by any antibiotic in the market. Since the ECF module is crucial for the vitamin transport mechanism, the prevention of substrate uptake should ultimately lead to cell death. By utilizing a combination of virtual and functional whole-cell screening of our in-house library, the membrane-bound protein mediated uptake of folate could be effectively inhibited. Structure-based optimization of our hit yielded low-micromolar inhibitors, whereby the most active compounds showed in addition potent antimicrobial activities against a panel of clinically relevant Gram-positive pathogens without significant cytotoxic effects. © 2022 American Chemical Society.
    • Merging bioresponsive release of insulin-like growth factor I with 3D printable thermogelling hydrogels

      Beudert, Matthias; Hahn, Lukas; Horn, Anselm H.C.; Hauptstein, Niklas; Sticht, Heinrich; Meinel, Lorenz; Luxenhofer, Robert; Gutmann, Marcus; Lühmann, Tessa (2022-07-01)
      3D printing of biomaterials enables spatial control of drug incorporation during automated manufacturing. This study links bioresponsive release of the anabolic biologic, insulin-like growth factor-I (IGF-I) in response to matrix metalloproteinases (MMP) to 3D printing using the block copolymer of poly(2-methyl-2-oxazoline) and thermoresponsive poly(2-n-propyl-2-oxazine) (POx-b-POzi). For that, a chemo-enzymatic synthesis was deployed, ligating IGF-I enzymatically to a protease sensitive linker (PSL), which was conjugated to a POx-b-POzi copolymer. The product was blended with the plain thermogelling POx-b-POzi hydrogel. MMP exposure of the resulting hydrogel triggered bioactive IGF-I release. The bioresponsive IGF-I containing POx-b-POzi hydrogel system was further detailed for shape control and localized incorporation of IGF-I via extrusion 3D printing for future applications in biomedicine and biofabrication. © 2022 Elsevier B.V.
    • POTATO: Automated pipeline for batch analysis of optical tweezers data.

      Buck, Stefan; Pekarek, Lukas; Caliskan, Neva; Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany ; Medical Faculty, Julius-Maximilians University Würzburg, Würzburg, Germany (Elsevier, Cell Press, 2022-06-30)
      Optical tweezers are a single-molecule technique that allows probing of intra- and intermolecular interactions that govern complex biological processes involving molecular motors, protein-nucleic acid interactions, and protein/RNA folding. Recent developments in instrumentation eased and accelerated optical tweezers data acquisition, but analysis of the data remains challenging. Here, to enable high-throughput data analysis, we developed an automated python-based analysis pipeline called POTATO (practical optical tweezers analysis tool). POTATO automatically processes the high-frequency raw data generated by force-ramp experiments and identifies (un)folding events using predefined parameters. After segmentation of the force-distance trajectories at the identified (un)folding events, sections of the curve can be fitted independently to a worm-like chain and freely jointed chain models, and the work applied on the molecule can be calculated by numerical integration. Furthermore, the tool allows plotting of constant force data and fitting of the Gaussian distance distribution over time. All these features are wrapped in a user-friendly graphical interface, which allows researchers without programming knowledge to perform sophisticated data analysis.
    • Microbial chassis engineering drives heterologous production of complex secondary metabolites

      Liu, Jiaqi; Wang, Xue; Dai, Guangzhi; Zhang, Youming; Bian, Xiaoying; a Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Shandong, Qingdao, 266237, China b Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8 1, Saarbrücken, 66123, Germany (Elsevier, 2022-04-26)
      The cryptic secondary metabolite biosynthetic gene clusters (BGCs) far outnumber currently known secondary metabolites. Heterologous production of secondary metabolite BGCs in suitable chassis facilitates yield improvement and discovery of new-to-nature compounds. The two juxtaposed conventional model microorganisms, Escherichia coli, Saccharomyces cerevisiae, have been harnessed as microbial chassis to produce a bounty of secondary metabolites with the help of certain host engineering. In last decade, engineering non-model microbes to efficiently biosynthesize secondary metabolites has received increasing attention due to their peculiar advantages in metabolic networks and/or biosynthesis. The state-of-the-art synthetic biology tools lead the way in operating genetic manipulation in non-model microorganisms for phenotypic optimization or yields improvement of desired secondary metabolites. In this review, we firstly discuss the pros and cons of several model and non-model microbial chassis, as well as the importance of developing broader non-model microorganisms as alternative programmable heterologous hosts to satisfy the desperate needs of biosynthesis study and industrial production. Then we highlight the lately advances in the synthetic biology tools and engineering strategies for optimization of non-model microbial chassis, in particular, the successful applications for efficient heterologous production of multifarious complex secondary metabolites, e.g., polyketides, nonribosomal peptides, as well as ribosomally synthesized and post-translationally modified peptides. Lastly, emphasis is on the perspectives of chassis cells development to access the ideal cell factory in the artificial intelligence-driven genome era. © 2022 Elsevier Inc.
    • CD4+ T cells play an essential role in chronic MC903-induced skin inflammation

      Song, Mi Hye; Gupta, Anupriya; Sasidharan Nair, Varun; Oh, Kwonik (Elsevier, 2022-04-25)
      MC903 skin inflammation model is one of well-characterized murine models of atopic dermatitis and driven by TSLP-mediated type 2 inflammation. Since it can be prepared simply by repetitive applications of MC903 and shows consistent clinical results, this model has been widely used. However, in contrast to human atopic dermatitis which is chronic and closely related to TH2 cells, MC903 induces inflammations temporarily and even in the absence of T cells. Here, we modified the MC903 treatment schedule and developed a chronic MC903-induced skin inflammation model. Mice were sensitized with a high dose of MC903 and challenged with a low dose of MC903. Prior to challenge, mice were allowed to recover completely from the inflammation which occurred during the sensitization. The challenge of MC903 induced skin swelling and type 2 inflammations more rapidly, which was dependent on CD4+ T cells and IL-33. We expect that our mouse model will be beneficial for studying the late course of atopic dermatitis. Keywords: Atopic dermatitis; CD4(+) T cell; Challenge; IL-33; MC903; Sensitization. Copyright © 2022 Elsevier Inc. All rights reserved.
    • The assessment of childhood maltreatment and its associations with affective symptoms in adulthood: Results of the German National Cohort (NAKO).

      Klinger-König, Johanna; Streit, Fabian; Erhardt, Angelika; Kleineidam, Luca; Schmiedek, Florian; Schmidt, Börge; Investigators, Nako; Wagner, Michael; Deckert, Jürgen; Rietschel, Marcella; et al. (Taylor and Francis, 2022-03-18)
      Overall, 21,131 participants (27.5%) reported at least one type of childhood maltreatment; 14,017 participants (18.3%) reported exactly one type and 250 participants (0.3%) reported all five types of childhood maltreatment. Small differences regarding age (mean absolute deviation around the mean (MAD)=0.47), sex (MAD = 0.07) and education (MAD = 0.82) were observed. The severity of childhood maltreatment was associated with more severe symptoms of depression (β = 0.23), anxiety (β = 0.21) and perceived stress (β = 0.23) in adulthood, validated particularly for emotional abuse and emotional neglect.
    • Total In Vitro Biosynthesis of the Thioamitide Thioholgamide and Investigation of the Pathway.

      Sikandar, Asfandyar; Lopatniuk, Maria; Luzhetskyy, Andriy; Müller, Rolf; Koehnke, Jesko; Department of Microbial Natural Products (MINS), Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Department of Pharmacy, Saarland University (UdS), Campus E8.1, Saarbrücken, 66123, GermanyDepartment of Pharmacy, Pharmaceutical Biotechnology, Saarland University, Saarbrücken, 66123, GermanyGerman Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Braunschweig, 38124, GermanyWorkgroup Structural Biology of Biosynthetic Enzymes, HIPS, HZI, UdS, Saarbrücken, 66123, GermanySchool of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom (ACS/ American Chemical Society, 2022-03-09)
      Thioholgamides are ribosomally synthesized and posttranslationally modified peptides (RiPPs), with potent activity against cancerous cell lines and an unprecedented structure. Despite being one of the most structurally and chemically complex RiPPs, very few biosynthetic steps have been elucidated. Here, we report the complete in vitro reconstitution of the biosynthetic pathway. We demonstrate that thioamidation is the first step and acts as a gatekeeper for downstream processing. Thr dehydration follows thioamidation, and our studies reveal that both these modifications require the formation of protein complexes─ThoH/I and ThoC/D. Harnessing the power of AlphaFold, we deduce that ThoD acts as a lyase and also proposes putative catalytic residues. ThoF catalyzes the oxidative decarboxylation of the terminal Cys, and the subsequent macrocyclization is facilitated by ThoE. This is followed by Ser dehydration, which is also carried out by ThoC/D. ThoG is responsible for histidine bis-N-methylation, which is a prerequisite for His β-hydroxylation─a modification carried out by ThoJ. The last step of the pathway is the removal of the leader peptide by ThoK to afford mature thioholgamide.
    • Optical Tweezers to Study RNA-Protein Interactions in Translation Regulation

      Pekarek, Lukas; Buck, Stefan; Caliskan, Neva; Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Zentrum für Infektionsforschung (Helmholtz Centre for Infection Research), Germany (JOVE, 2022-02-12)
      RNA adopts diverse structural folds, which are essential for its functions and thereby can impact diverse processes in the cell. In addition, the structure and function of an RNA can be modulated by various trans-acting factors, such as proteins, metabolites or other RNAs. Frameshifting RNA molecules, for instance, are regulatory RNAs located in coding regions, which direct translating ribosomes into an alternative open reading frame, and thereby act as gene switches. They may also adopt different folds after binding to proteins or other trans-factors. To dissect the role of RNA-binding proteins in translation and how they modulate RNA structure and stability, it is crucial to study the interplay and mechanical features of these RNA-protein complexes simultaneously. This work illustrates how to employ single-molecule-fluorescence-coupled optical tweezers to explore the conformational and thermodynamic landscape of RNA-protein complexes at a high resolution. As an example, the interaction of the SARS-CoV-2 programmed ribosomal frameshifting element with the trans-acting factor short isoform of zinc-finger antiviral protein is elaborated. In addition, fluorescence-labeled ribosomes were monitored using the confocal unit, which would ultimately enable the study of translation elongation. The fluorescence coupled OT assay can be widely applied to explore diverse RNA-protein complexes or trans-acting factors regulating translation and could facilitate studies of RNA-based gene regulation.
    • Inhibition of MCL1 induces apoptosis in anaplastic large cell lymphoma and in primary effusion lymphoma.

      Quentmeier, Hilmar; Geffers, Robert; Hauer, Vivien; Nagel, Stefan; Pommerenke, Claudia; Uphoff, Cord C; Zaborski, Margarete; Drexler, Hans G; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Nature, 2022-01-20)
      Overexpression of antiapoptotic BCL2 family proteins occurs in various hematologic malignancies and contributes to tumorigenesis by inhibiting the apoptotic machinery of the cells. Antagonizing BH3 mimetics provide an option for medication, with venetoclax as the first drug applied for chronic lymphocytic leukemia and for acute myeloid leukemia. To find additional hematologic entities with ectopic expression of BCL2 family members, we performed expression screening of cell lines applying the LL-100 panel. Anaplastic large cell lymphoma (ALCL) and primary effusion lymphoma (PEL), 2/22 entities covered by this panel, stood out by high expression of MCL1 and low expression of BCL2. The MCL1 inhibitor AZD-5991 induced apoptosis in cell lines from both malignancies, suggesting that this BH3 mimetic might be efficient as drug for these diseases. The ALCL cell lines also expressed BCLXL and BCL2A1, both contributing to survival of the cells. The combination of specific BH3 mimetics yielded synergistic effects, pointing to a novel strategy for the treatment of ALCL. The PI3K/mTOR inhibitor BEZ-235 could also efficiently be applied in combination with AZD-5991, offering an alternative to avoid thrombocytopenia which is associated with the use of BCLXL inhibitors.
    • Global RNA interactome of Salmonella discovers a 5' UTR sponge for the MicF small RNA that connects membrane permeability to transport capacity.

      Matera, Gianluca; Altuvia, Yael; Gerovac, Milan; El Mouali, Youssef; Margalit, Hanah; Vogel, Jörg; HIRI, Helmholtz-Institut für RNA-basierte Infektionsforschung, Josef-Shneider Strasse 2, 97080 Würzburg, Germany. (Elsevier (Cell Press), 2022-01-20)
      The envelope of Gram-negative bacteria is a vital barrier that must balance protection and nutrient uptake. Small RNAs are crucial regulators of the envelope composition and function. Here, using RIL-seq to capture the Hfq-mediated RNA-RNA interactome in Salmonella enterica, we discover envelope-related riboregulators, including OppX. We show that OppX acts as an RNA sponge of MicF sRNA, a prototypical porin repressor. OppX originates from the 5' UTR of oppABCDF, encoding the major inner-membrane oligopeptide transporter, and sequesters MicF's seed region to derepress the synthesis of the porin OmpF. Intriguingly, OppX operates as a true sponge, storing MicF in an inactive complex without affecting its levels or stability. Conservation of the opp-OppX-MicF-ompF axis in related bacteria suggests that it serves an important mechanism, adjusting envelope porosity to specific transport capacity. These data also highlight the resource value of this Salmonella RNA interactome, which will aid in unraveling RNA-centric regulation in enteric pathogens.
    • New Deoxyenhygrolides from Provide Insights into Butenolide Core Biosynthesis.

      Hug, Joachim J; Kjaerulff, Louise; Garcia, Ronald; Müller, Rolf; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (MDPI, 2022-01-14)
      Marine myxobacteria present a virtually unexploited reservoir for the discovery of natural products with diverse biological functions and novel chemical scaffolds. We report here the isolation and structure elucidation of eight new deoxyenhygrolides (1-8) from the marine myxobacterium Plesiocystis pacifica DSM 14875T. The herein described deoxyenhygrolides C-J (1-8) feature a butenolide core with an ethyl residue at C-3 of the γ-lactone in contrast to the previously described derivatives, deoxyenhygrolides A and B, which feature an isobutyl residue at this position. The butenolide core is 2,4-substituted with a benzyl (1, 2 and 7), benzoyl (3 and 4) or benzyl alcohol (5, 6 and 8) moiety in the 2-position and a benzylidene (1-6) or benzylic hemiketal (7 and 8) in the 4-position. The description of these new deoxyenhygrolide derivatives, alongside genomic in silico investigation regarding putative biosynthetic genes, provides some new puzzle pieces on how this natural product class might be formed by marine myxobacteria.
    • Itaconate and derivatives reduce interferon responses and inflammation in influenza A virus infection.

      Sohail, Aaqib; Iqbal, Azeem A; Sahini, Nishika; Chen, Fangfang; Tantawy, Mohamed; Waqas, Fakhar; Winterhoff, Moritz; Ebensen, Thomas; Schultz, Kristin; Geffers, Robert; et al. (PLOS, 2022-01-13)
      Excessive inflammation is a major cause of morbidity and mortality in many viral infections including influenza. Therefore, there is a need for therapeutic interventions that dampen and redirect inflammatory responses and, ideally, exert antiviral effects. Itaconate is an immunomodulatory metabolite which also reprograms cell metabolism and inflammatory responses when applied exogenously. We evaluated effects of endogenous itaconate and exogenous application of itaconate and its variants dimethyl- and 4-octyl-itaconate (DI, 4OI) on host responses to influenza A virus (IAV). Infection induced expression of ACOD1, the enzyme catalyzing itaconate synthesis, in monocytes and macrophages, which correlated with viral replication and was abrogated by DI and 4OI treatment. In IAV-infected mice, pulmonary inflammation and weight loss were greater in Acod1-/- than in wild-type mice, and DI treatment reduced pulmonary inflammation and mortality. The compounds reversed infection-triggered interferon responses and modulated inflammation in human cells supporting non-productive and productive infection, in peripheral blood mononuclear cells, and in human lung tissue. Itaconates reduced ROS levels and STAT1 phosphorylation, whereas AKT phosphorylation was reduced by 4OI and DI but increased by itaconate. Single-cell RNA sequencing identified monocytes as the main target of infection and the exclusive source of ACOD1 mRNA in peripheral blood. DI treatment silenced IFN-responses predominantly in monocytes, but also in lymphocytes and natural killer cells. Ectopic synthesis of itaconate in A549 cells, which do not physiologically express ACOD1, reduced infection-driven inflammation, and DI reduced IAV- and IFNγ-induced CXCL10 expression in murine macrophages independent of the presence of endogenous ACOD1. The compounds differed greatly in their effects on cellular gene homeostasis and released cytokines/chemokines, but all three markedly reduced release of the pro-inflammatory chemokines CXCL10 (IP-10) and CCL2 (MCP-1). Viral replication did not increase under treatment despite the dramatically repressed IFN responses. In fact, 4OI strongly inhibited viral transcription in peripheral blood mononuclear cells, and the compounds reduced viral titers (4OI>Ita>DI) in A549 cells whereas viral transcription was unaffected. Taken together, these results reveal itaconates as immunomodulatory and antiviral interventions for influenza virus infection.
    • Novel 2,4-disubstituted quinazoline analogs as antibacterial agents with improved cytotoxicity profile: Modification of the benzenoid part.

      Megahed, Sarah H; Rasheed, Sari; Herrmann, Jennifer; El-Hossary, Ebaa M; El-Shabrawy, Yahia I; Abadi, Ashraf H; Engel, Matthias; Müller, Rolf; Abdel-Halim, Mohammad; Hamed, Mostafa M; et al. (Elsevier Ltd., 2022-01-07)
      Bacterial resistance to currently used antibiotics demands the development of novel antibacterial agents with good safety margins and sufficient efficacy against multi-drug resistant isolates. We have previously described the synthesis of N-butyl-2-(butylthio)quinazolin-4-amine (I) as an optimized hit with broad-spectrum antibacterial activity and low cytotoxicity. In addition, we have identified a potential growing vector for this series of compounds. Herein, we describe further hit optimization which includes systematic diversifications of both the benzenoid part and the substituents at position 6 and 7 of compound I. Growing of the molecule beside the core modifications yielded several compounds with remarkable anti(myco)bacterial activity against a panel of pathogenic bacteria, including drug-resistant strains. Compound 12 showed a 2-4 fold improvement in activity than I against S. aureus Newman, S. pneumoniae DSM-20566 and E. faecalis DSM-20478. The compounds also showed a good safety profile towards human HepG2 cells.
    • Symptom Burden and Factors Associated with Acute Respiratory Infections in the First Two Years of Life-Results from the LoewenKIDS Cohort.

      Langer, Susan; Horn, Johannes; Gottschick, Cornelia; Klee, Bianca; Purschke, Oliver; Caputo, Mahrrouz; Dorendorf, Evelyn; Meyer-Schlinkmann, Kristin Maria; Raupach-Rosin, Heike; Karch, André; et al. (MDPI, 2022-01-05)
      Acute respiratory infections (ARIs) are the most common childhood illnesses worldwide whereby the reported frequency varies widely, often depending on type of assessment. Symptom diaries are a powerful tool to counteract possible under-reporting, particularly of milder infections, and thus offer the possibility to assess the full burden of ARIs. The following analyses are based on symptom diaries from participants of the German birth cohort study LoewenKIDS. Primary analyses included frequencies of ARIs and specific symptoms. Factors, which might be associated with an increased number of ARIs, were identified using the Poisson regression. A subsample of two hundred eighty-eight participants were included. On average, 13.7 ARIs (SD: 5.2 median: 14.0 IQR: 10-17) were reported in the first two years of life with an average duration of 11 days per episode (SD: 5.8, median: 9.7, IQR: 7-14). The median age for the first ARI episode was 91 days (IQR: 57-128, mean: 107, SD: 84.5). Childcare attendance and having siblings were associated with an increased frequency of ARIs, while exclusive breastfeeding for the first three months was associated with less ARIs, compared to exclusive breastfeeding for a longer period. This study provides detailed insight into the symptom burden of ARIs in German infants.
    • Pentacyclic Triterpenoids, Phytosteroids and Fatty Acid Isolated from the Stem-bark of Cola lateritia K. Schum. (Sterculiaceae) of Cameroon origin; Evaluation of Their Antibacterial Activity

      Kamdem, Michael H.K.; Ojo, Olusesan; Kemkuignou, Blondelle M.; Talla, Rostan M.; Fonkui, Thierry Y.; Silihe, Kevine K.; Tata, Charlotte M.; Fotsing, Marthe C.D.; Mmutlane, Edwin M.; Ndinteh, Derek T. (Elsevier, 2022-01-01)
      The phytochemical investigation on the chemical constituents of dichloromethane-methanol (1:1) stem-bark extract ofCola lateritiaK. Schum. (Sterculiaceae) led to the isolationand characterization of five pentacyclic triterpenoids, one fatty acid and two phytosteroids. Thecompounds were identified as heptadecanoic acid (1), maslinic acid (2), betulinic acid (3), lupenone(4), lupeol (5), friedelin (6),b-stigmasterol (7) andß-sitosterol-3-O-ß-D-glucoside (8). Their struc-tures were determined by NMR analysis (1H,13C, DEPT-135, COSY, HMBC and HSQC), high-resolution mass spectrometry (HR-ESI-MS) and comparisons with published data in the literature.This work, to the best of our knowledge, is the first isolation and identification of these compoundsin pure forms fromCola lateritia. Also, compounds1–3are reported for the first time fromColagenus.In vitroantibacterial activity of the isolated compounds (1–8) and the crude extract wereevaluated againstBacillus subtilis,Staphylococcus epidermidis,Enterococcus faecalis,Mycobacterium smegmatis,Staphylococcus aureus,Enterobacter cloacae,Klebsiella oxytoca,Proteusvulgaris,Klebsiella pneumonia,Escherichia coli, Proteus mirabilisandKlebsiella aerogeneswithstreptomycin, nalidixic acid and ampicillin as standard antibacterial drugs. Compound2was activeagainstE. faecalis(MIC = 18.5mg/mL), and it was 6.9 and 28 times lower and active than that ofstreptomycin (MIC 128mg/mL) and nalidixic acid (MIC>512mg/mL) respectively. All the isolatedcompounds and crude extract showed significant activities against the tested bacterial strains.
    • Complement activation induces excessive T cell cytotoxicity in severe COVID-19.

      Georg, Philipp; Astaburuaga-García, Rosario; Bonaguro, Lorenzo; Brumhard, Sophia; Michalick, Laura; Lippert, Lena J; Kostevc, Tomislav; Gäbel, Christiane; Schneider, Maria; Streitz, Mathias; et al. (Elsevier, 2021-12-28)
      Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.
    • Preclinical Assessment of Bacteriophage Therapy against Experimental Lung Infection.

      Wienhold, Sandra-Maria; Brack, Markus C; Nouailles, Geraldine; Krishnamoorthy, Gopinath; Korf, Imke H E; Seitz, Claudius; Wienecke, Sarah; Dietert, Kristina; Gurtner, Corinne; Kershaw, Olivia; et al. (MDPI, 2021-12-24)
      Respiratory infections caused by multidrug-resistant Acinetobacter baumannii are difficult to treat and associated with high mortality among critically ill hospitalized patients. Bacteriophages (phages) eliminate pathogens with high host specificity and efficacy. However, the lack of appropriate preclinical experimental models hampers the progress of clinical development of phages as therapeutic agents. Therefore, we tested the efficacy of a purified lytic phage, vB_AbaM_Acibel004, against multidrug-resistant A. baumannii clinical isolate RUH 2037 infection in immunocompetent mice and a human lung tissue model. Sham- and A. baumannii-infected mice received a single-dose of phage or buffer via intratracheal aerosolization. Group-specific differences in bacterial burden, immune and clinical responses were compared. Phage-treated mice not only recovered faster from infection-associated hypothermia but also had lower pulmonary bacterial burden, lower lung permeability, and cytokine release. Histopathological examination revealed less inflammation with unaffected inflammatory cellular recruitment. No phage-specific adverse events were noted. Additionally, the bactericidal effect of the purified phage on A. baumannii was confirmed after single-dose treatment in an ex vivo human lung infection model. Taken together, our data suggest that the investigated phage has significant potential to treat multidrug-resistant A. baumannii infections and further support the development of appropriate methods for preclinical evaluation of antibacterial efficacy of phages.
    • Bacteriomimetic Liposomes Improve Antibiotic Activity of a Novel Energy-Coupling Factor Transporter Inhibitor.

      Drost, Menka; Diamanti, Eleonora; Fuhrmann, Kathrin; Goes, Adriely; Shams, Atanaz; Haupenthal, Jörg; Koch, Marcus; Hirsch, Anna K H; Fuhrmann, Gregor; HIRI, Helmholtz-Institut für RNA-basierte Infektionsforschung, Josef-Shneider Strasse 2, 97080 Würzburg, Germany. (MDPI, 2021-12-21)
      Liposomes have been studied for decades as nanoparticulate drug delivery systems for cytostatics, and more recently, for antibiotics. Such nanoantibiotics show improved antibacterial efficacy compared to the free drug and can be effective despite bacterial recalcitrance. In this work, we present a loading method of bacteriomimetic liposomes for a novel, hydrophobic compound (HIPS5031) inhibiting energy-coupling factor transporters (ECF transporters), an underexplored antimicrobial target. The liposomes were composed of DOPG (18:1 (Δ9-cis) phosphatidylglycerol) and CL (cardiolipin), resembling the cell membrane of Gram-positive Staphylococcus aureus and Streptococcus pneumoniae, and enriched with cholesterol (Chol). The size and polydispersity of the DOPG/CL/± Chol liposomes remained stable over 8 weeks when stored at 4 °C. Loading of the ECF transporter inhibitor was achieved by thin film hydration and led to a high encapsulation efficiency of 33.19% ± 9.5% into the DOPG/CL/Chol liposomes compared to the phosphatidylcholine liposomes (DMPC/DPPC). Bacterial growth inhibition assays on the model organism Bacillus subtilis revealed liposomal HIPS5031 as superior to the free drug, showing a 3.5-fold reduction in CFU/mL at a concentration of 9.64 µM. Liposomal HIPS5031 was also shown to reduce B. subtilis biofilm. Our findings present an explorative basis for bacteriomimetic liposomes as a strategy against drug-resistant pathogens by surpassing the drug-formulation barriers of innovative, yet unfavorably hydrophobic, antibiotics.
    • Beneficial and detrimental functions of microglia during viral encephalitis.

      Waltl, Inken; Kalinke, Ulrich; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Elsevier (Cell Press), 2021-12-11)
      icroglia are resident immune cells of the central nervous system (CNS) with multiple functions in health and disease. Their response during encephalitis depends on whether inflammation is triggered in a sterile or infectious manner, and in the latter case on the type of the infecting pathogen. Even though recent technological innovations advanced the understanding of the broad spectrum of microglia responses during viral encephalitis (VE), it is not entirely clear which microglia gene expression profiles are associated with antiviral and detrimental activities. Here, we review novel approaches to study microglia and the latest concepts of their function in VE. Improved understanding of microglial functions will be essential for the development of new therapeutic interventions for VE.