Publications by authors named "Markus Hoffmann"

184 Publications

Therapeutic Application of alpha-1-antitrypsin in COVID-19.

Am J Respir Crit Care Med 2021 May 7. Epub 2021 May 7.

Saarland University Hospital and Saarland University Faculty of Medicine, 39072, Internal Medicine V - Pulmonology, Homburg, Germany;

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http://dx.doi.org/10.1164/rccm.202104-0833LEDOI Listing
May 2021

Inhibition of acid sphingomyelinase by ambroxol prevents SARS-CoV-2 entry into epithelial cells.

J Biol Chem 2021 Apr 22:100701. Epub 2021 Apr 22.

Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122, Essen, Germany; Department of Surgery, Medical School, University of Cincinnati, 231 Albert Sabin Way, ML0558, Cincinnati, OH, 45267, USA. Electronic address:

The acid sphingomyelinase/ceramide system has been shown to be important for cellular infection with at least some viruses, for instance rhinovirus or SARS-CoV-2. Functional inhibition of the acid sphingomyelinase using tricyclic antidepressants prevented infection of epithelial cells, for instance with SARS-CoV-2. The structure of ambroxol, i.e. trans-4-[(2,4-dibromanilin-6-yl)-methyamino]-cyclohexanol, a mucolytic drug applied by inhalation, suggests that the drug might inhibit the acid sphingomyelinase, and thereby infection with SARS-CoV-2. To test this, we used spike protein pseudotyped viral particles (pp-VSV-SARS-CoV-2 spike), a bona fide system for mimicking SARS-CoV-2 entry into cells. Viral uptake and formation of ceramide localization were determined by fluorescence microscopy, activity of the acid sphingomyelinase by consumption of [C]sphingomyelin and ceramide was quantified by a kinase method. We found that entry of pp-VSV-SARS-CoV-2 spike required activation of acid sphingomyelinase and release of ceramide, events that were all prevented by pretreatment with ambroxol. We also obtained nasal epithelial cells from human volunteers prior to and after inhalation of ambroxol. Inhalation of ambroxol reduced acid sphingomyelinase activity in nasal epithelial cells, and prevented pp-VSV-SARS-CoV-2 spike-induced acid sphingomyelinase activation, ceramide release, and entry of pp-VSV-SARS-CoV-2 spike ex vivo. The addition of purified acid sphingomyelinase or C16 ceramide restored entry of pp-VSV-SARS-CoV-2 spike into ambroxol-treated epithelial cells. We propose that ambroxol might be suitable for clinical studies to prevent COVID-19.
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http://dx.doi.org/10.1016/j.jbc.2021.100701DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8062550PMC
April 2021

The SARS-CoV-2 and other human coronavirus spike proteins are fine-tuned towards temperature and proteases of the human airways.

PLoS Pathog 2021 04 22;17(4):e1009500. Epub 2021 Apr 22.

KU Leuven, Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium.

The high transmissibility of SARS-CoV-2 is related to abundant replication in the upper airways, which is not observed for the other highly pathogenic coronaviruses SARS-CoV and MERS-CoV. We here reveal features of the coronavirus spike (S) protein, which optimize the virus towards the human respiratory tract. First, the S proteins exhibit an intrinsic temperature preference, corresponding with the temperature of the upper or lower airways. Pseudoviruses bearing the SARS-CoV-2 spike (SARS-2-S) were more infectious when produced at 33°C instead of 37°C, a property shared with the S protein of HCoV-229E, a common cold coronavirus. In contrast, the S proteins of SARS-CoV and MERS-CoV favored 37°C, in accordance with virus preference for the lower airways. Next, SARS-2-S-driven entry was efficiently activated by not only TMPRSS2, but also the TMPRSS13 protease, thus broadening the cell tropism of SARS-CoV-2. Both proteases proved relevant in the context of authentic virus replication. TMPRSS13 appeared an effective spike activator for the virulent coronaviruses but not the low pathogenic HCoV-229E virus. Activation of SARS-2-S by these surface proteases requires processing of the S1/S2 cleavage loop, in which both the furin recognition motif and extended loop length proved critical. Conversely, entry of loop deletion mutants is significantly increased in cathepsin-rich cells. Finally, we demonstrate that the D614G mutation increases SARS-CoV-2 stability, particularly at 37°C, and, enhances its use of the cathepsin L pathway. This indicates a link between S protein stability and usage of this alternative route for virus entry. Since these spike properties may promote virus spread, they potentially explain why the spike-G614 variant has replaced the early D614 variant to become globally predominant. Collectively, our findings reveal adaptive mechanisms whereby the coronavirus spike protein is adjusted to match the temperature and protease conditions of the airways, to enhance virus transmission and pathology.
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http://dx.doi.org/10.1371/journal.ppat.1009500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8061995PMC
April 2021

SARS-CoV-2 mutations acquired in mink reduce antibody-mediated neutralization.

Cell Rep 2021 04 3;35(3):109017. Epub 2021 Apr 3.

Infection Biology Unit, German Primate Center - Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany; Faculty of Biology and Psychology, University Göttingen, Wilhelmsplatz 1, 37073 Göttingen, Germany. Electronic address:

Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from humans to farmed mink has been observed in Europe and the US. In the infected animals, viral variants arose that harbored mutations in the spike (S) protein, the target of neutralizing antibodies, and these variants were transmitted back to humans. This raised concerns that mink might become a constant source of human infection with SARS-CoV-2 variants associated with an increased threat to human health and resulted in mass culling of mink. Here, we report that mutations frequently found in the S proteins of SARS-CoV-2 from mink are mostly compatible with efficient entry into human cells and its inhibition by soluble angiotensin-converting enzyme 2 (ACE2). In contrast, mutation Y453F reduces neutralization by an antibody with emergency use authorization for coronavirus disease 2019 (COVID-19) therapy and sera/plasma from COVID-19 patients. These results suggest that antibody responses induced upon infection or certain antibodies used for treatment might offer insufficient protection against SARS-CoV-2 variants from mink.
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http://dx.doi.org/10.1016/j.celrep.2021.109017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018833PMC
April 2021

SARS-CoV-2 variants B.1.351 and P.1 escape from neutralizing antibodies.

Cell 2021 04 20;184(9):2384-2393.e12. Epub 2021 Mar 20.

Infection Biology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany; Faculty of Biology and Psychology, Georg-August-University Göttingen, Wilhelmsplatz 1, 37073 Göttingen, Germany. Electronic address:

The global spread of SARS-CoV-2/COVID-19 is devastating health systems and economies worldwide. Recombinant or vaccine-induced neutralizing antibodies are used to combat the COVID-19 pandemic. However, the recently emerged SARS-CoV-2 variants B.1.1.7 (UK), B.1.351 (South Africa), and P.1 (Brazil) harbor mutations in the viral spike (S) protein that may alter virus-host cell interactions and confer resistance to inhibitors and antibodies. Here, using pseudoparticles, we show that entry of all variants into human cells is susceptible to blockade by the entry inhibitors soluble ACE2, Camostat, EK-1, and EK-1-C4. In contrast, entry of the B.1.351 and P.1 variant was partially (Casirivimab) or fully (Bamlanivimab) resistant to antibodies used for COVID-19 treatment. Moreover, entry of these variants was less efficiently inhibited by plasma from convalescent COVID-19 patients and sera from BNT162b2-vaccinated individuals. These results suggest that SARS-CoV-2 may escape neutralizing antibody responses, which has important implications for efforts to contain the pandemic.
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http://dx.doi.org/10.1016/j.cell.2021.03.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980144PMC
April 2021

The complement system drives local inflammatory tissue priming by metabolic reprogramming of synovial fibroblasts.

Immunity 2021 Mar 19. Epub 2021 Mar 19.

Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, 91054 Erlangen, Germany; Deutsches Zentrum fuer Immuntherapie, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, 91054 Erlangen, Germany.

Arthritis typically involves recurrence and progressive worsening at specific predilection sites, but the checkpoints between remission and persistence remain unknown. Here, we defined the molecular and cellular mechanisms of this inflammation-mediated tissue priming. Re-exposure to inflammatory stimuli caused aggravated arthritis in rodent models. Tissue priming developed locally and independently of adaptive immunity. Repeatedly stimulated primed synovial fibroblasts (SFs) exhibited enhanced metabolic activity inducing functional changes with intensified migration, invasiveness and osteoclastogenesis. Meanwhile, human SF from patients with established arthritis displayed a similar primed phenotype. Transcriptomic and epigenomic analyses as well as genetic and pharmacological targeting demonstrated that inflammatory tissue priming relies on intracellular complement C3- and C3a receptor-activation and downstream mammalian target of rapamycin- and hypoxia-inducible factor 1α-mediated metabolic SF invigoration that prevents activation-induced senescence, enhances NLRP3 inflammasome activity, and in consequence sensitizes tissue for inflammation. Our study suggests possibilities for therapeutic intervention abrogating tissue priming without immunosuppression.
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http://dx.doi.org/10.1016/j.immuni.2021.03.003DOI Listing
March 2021

Alpha-1 antitrypsin inhibits TMPRSS2 protease activity and SARS-CoV-2 infection.

Nat Commun 2021 03 19;12(1):1726. Epub 2021 Mar 19.

Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany.

SARS-CoV-2 is a respiratory pathogen and primarily infects the airway epithelium. As our knowledge about innate immune factors of the respiratory tract against SARS-CoV-2 is limited, we generated and screened a peptide/protein library derived from bronchoalveolar lavage for inhibitors of SARS-CoV-2 spike-driven entry. Analysis of antiviral fractions revealed the presence of α-antitrypsin (αAT), a highly abundant circulating serine protease inhibitor. Here, we report that αAT inhibits SARS-CoV-2 entry at physiological concentrations and suppresses viral replication in cell lines and primary cells including human airway epithelial cultures. We further demonstrate that αAT binds and inactivates the serine protease TMPRSS2, which enzymatically primes the SARS-CoV-2 spike protein for membrane fusion. Thus, the acute phase protein αAT is an inhibitor of TMPRSS2 and SARS-CoV-2 entry, and may play an important role in the innate immune defense against the novel coronavirus. Our findings suggest that repurposing of αAT-containing drugs has prospects for the therapy of COVID-19.
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http://dx.doi.org/10.1038/s41467-021-21972-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7979852PMC
March 2021

Camostat mesylate inhibits SARS-CoV-2 activation by TMPRSS2-related proteases and its metabolite GBPA exerts antiviral activity.

EBioMedicine 2021 Mar 4;65:103255. Epub 2021 Mar 4.

Infection Biology Unit, German Primate Center - Leibniz Institute for Primate Research, 37077 Göttingen, Germany; Faculty of Biology and Psychology, University Göttingen, 37073 Göttingen, Germany. Electronic address:

Background: Antivirals are needed to combat the COVID-19 pandemic, which is caused by SARS-CoV-2. The clinically-proven protease inhibitor Camostat mesylate inhibits SARS-CoV-2 infection by blocking the virus-activating host cell protease TMPRSS2. However, antiviral activity of Camostat mesylate metabolites and potential viral resistance have not been analyzed. Moreover, antiviral activity of Camostat mesylate in human lung tissue remains to be demonstrated.

Methods: We used recombinant TMPRSS2, reporter particles bearing the spike protein of SARS-CoV-2 or authentic SARS-CoV-2 to assess inhibition of TMPRSS2 and viral entry, respectively, by Camostat mesylate and its metabolite GBPA.

Findings: We show that several TMPRSS2-related proteases activate SARS-CoV-2 and that two, TMPRSS11D and TMPRSS13, are robustly expressed in the upper respiratory tract. However, entry mediated by these proteases was blocked by Camostat mesylate. The Camostat metabolite GBPA inhibited recombinant TMPRSS2 with reduced efficiency as compared to Camostat mesylate. In contrast, both inhibitors exhibited similar antiviral activity and this correlated with the rapid conversion of Camostat mesylate into GBPA in the presence of serum. Finally, Camostat mesylate and GBPA blocked SARS-CoV-2 spread in human lung tissue ex vivo and the related protease inhibitor Nafamostat mesylate exerted augmented antiviral activity.

Interpretation: Our results suggest that SARS-CoV-2 can use TMPRSS2 and closely related proteases for spread in the upper respiratory tract and that spread in the human lung can be blocked by Camostat mesylate and its metabolite GBPA.

Funding: NIH, Damon Runyon Foundation, ACS, NYCT, DFG, EU, Berlin Mathematics center MATH+, BMBF, Lower Saxony, Lundbeck Foundation, Novo Nordisk Foundation.
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http://dx.doi.org/10.1016/j.ebiom.2021.103255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930809PMC
March 2021

Mutation D614G increases SARS-CoV-2 transmission.

Signal Transduct Target Ther 2021 03 1;6(1):101. Epub 2021 Mar 1.

Infection Biology Unit, German Primate Center, Göttingen, Germany.

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http://dx.doi.org/10.1038/s41392-021-00502-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919247PMC
March 2021

'SMASH' recommendations for standardised microscopic arthritis scoring of histological sections from inflammatory arthritis animal models.

Ann Rheum Dis 2021 Feb 18. Epub 2021 Feb 18.

Department of Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands.

Animal models for inflammatory arthritides such as rheumatoid arthritis (RA) and psoriatic arthritis are widely accepted and frequently used to identify pathological mechanisms and validate novel therapeutic strategies. Unfortunately, many publications reporting on these animal studies lack detailed description and appropriate assessment of the distinct histopathological features of arthritis: joint inflammation, cartilage damage and bone erosion. Therefore, the European consortium BeTheCure, consisting of 38 academic and industrial partners from 15 countries, set as goal to standardise the histological evaluation of joint sections from animal models of inflammatory arthritis. The consensual approach of a task force including 16 academic and industrial scientists as well as laboratory technicians has resulted in the development of the Standardised Microscopic Arthritis Scoring of Histological sections ('SMASH') recommendations for a standardised processing and microscopic scoring of the characteristic histopathological features of arthritis, exemplified by four different rodent models for arthritis: murine collagen-induced arthritis, collagen-antibody-induced arthritis, human tumour necrosis factor transgenic Tg197 mice and rat pristane-induced arthritis, applicable to any other inflammatory arthritis model. Through standardisation, the SMASH recommendations are designed to improve and maximise the information derived from in vivo arthritis experiments and to promote reproducibility and transparent reporting on such studies. In this manuscript, we will discuss and provide recommendations for analysis of histological joint sections: identification of the regions of interest, sample preparation, staining procedures and quantitative scoring methods. In conclusion, awareness of the different features of the arthritis pathology in animal models of inflammatory arthritis is of utmost importance for reliable research outcome, and the standardised histological processing and scoring methods in these SMASH recommendations will help increase uniformity and reproducibility in preclinical research on inflammatory arthritis.
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http://dx.doi.org/10.1136/annrheumdis-2020-219247DOI Listing
February 2021

assay to evaluate the efficacy of drugs targeting sphingolipids in preventing SARS-CoV-2 infection of nasal epithelial cells.

STAR Protoc 2021 Mar 3;2(1):100356. Epub 2021 Feb 3.

Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.

This protocol enables the testing of drugs against infection of epithelial cells with SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2), using pseudo-typed replication deficient vesicular stomatitis virus particles (pp-VSV) presenting the SARS-CoV-2 spike protein. After treating human volunteers with amitriptyline, an approved antidepressant and inhibitor of the acid sphingomyelinase, freshly isolated nasal epithelial cells were infected and infection levels were quantified. This protocol offers the possibility to rapidly test the efficacy of potential drugs in the fight against COVID-19. For complete details on the use and execution of this protocol, please refer to Carpinteiro et al. (2020).
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http://dx.doi.org/10.1016/j.xpro.2021.100356DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857112PMC
March 2021

Stromal-driven and Amyloid β-dependent induction of neutrophil extracellular traps modulates tumor growth.

Nat Commun 2021 01 29;12(1):683. Epub 2021 Jan 29.

MRC Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Box 197 Cambridge Biomedical Campus, Cambridge, CB2 0XZ, England.

Tumors consist of cancer cells and a network of non-cancerous stroma. Cancer-associated fibroblasts (CAF) are known to support tumorigenesis, and are emerging as immune modulators. Neutrophils release histone-bound nuclear DNA and cytotoxic granules as extracellular traps (NET). Here we show that CAFs induce NET formation within the tumor and systemically in the blood and bone marrow. These tumor-induced NETs (t-NETs) are driven by a ROS-mediated pathway dependent on CAF-derived Amyloid β, a peptide implicated in both neurodegenerative and inflammatory disorders. Inhibition of NETosis in murine tumors skews neutrophils to an anti-tumor phenotype, preventing tumor growth; reciprocally, t-NETs enhance CAF activation. Mirroring observations in mice, CAFs are detected juxtaposed to NETs in human melanoma and pancreatic adenocarcinoma, and show elevated amyloid and β-Secretase expression which correlates with poor prognosis. In summary, we report that CAFs drive NETosis to support cancer progression, identifying Amyloid β as the protagonist and potential therapeutic target.
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http://dx.doi.org/10.1038/s41467-021-20982-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846803PMC
January 2021

Dalbavancin: novel candidate for COVID-19 treatment.

Cell Res 2021 03;31(3):243-244

Infection Biology Unit, German Primate Center, 37077, Göttingen, Germany.

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http://dx.doi.org/10.1038/s41422-020-00459-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7816554PMC
March 2021

The interaction of smoking habit, SLPI and AnxA2 in HPV associated head and neck and other cancers.

Cancer Treat Res Commun 2021 26;26:100299. Epub 2020 Dec 26.

Department of Otorhinolaryngology, Head and Neck Surgery, Christian-Albrechts-University, Arnold-Heller-Str. 3, D-24105 Kiel, Germany.

Six own studies confirm a correlation between smoking, expression of the secretory leukocyte protease inhibitor (SLPI, an antileukoproteinase) and expression of Annexin A2 (AnxA2), and their influence on human papilloma virus (HPV)-infections. SLPI and HPV are ligands of AnxA2. This correlation was tested on 928 tissue samples from 892 patients in six independent studies [squamous cell carcinoma of the head and neck (HNSCC), n = 522; non-neoplastic tonsils n = 214; clinically normal mucosa, n = 93 (of these n = 57 were obtained from patients treated for non-malignant diseases and n = 36 were obtained from HNSCC-patients) and vulvar squamous cell carcinoma (VSCC) n = 99]. HPV-DNA-status was determined by GP5+/GP6+-PCR, followed in case of HPV-positivity by Sanger sequencing and RT-PCR using HPV-type specific primers. SLPI- and AnxA2-gene-expression was determined by RT-q-PCR; SLPI-protein-expression was additionally determined by immunohistochemistry (IHC); the data were correlated with each other and with patient characteristics. Smoking results in increased SLPI-gene- and protein- and AnxA2-gene-expression with significantly higher SLPI- than AnxA2-gene-expression. SLPI is decreased in non-smokers with a continuous AnxA2-surplus. HPV-status correlates with smoking habit, with smokers being mostly HPV-negative and non-smokers HPV-positive. We hypothesize that smoking leads to SLPI-overexpression with SLPI-binding to AnxA2. Thus, HPV cannot bind to AnxA2 but this seems pivotal for HPV-cell-entry. Smoking favors SLPI-expression resulting in HPV-negative carcinomas, while HPV-positive carcinomas are more common in non-smokers possibly due to a surplus of unbound AnxA2. In addition, the hypothesis may contribute to understand why smokers show increased oral HPV-prevalence in natural history studies but do not necessarily develop HPV-associated lesions.
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http://dx.doi.org/10.1016/j.ctarc.2020.100299DOI Listing
December 2020

HPV DNA/RNA detection in various oral and oropharyngeal biomaterials identifies active HPV infections also in non-neoplastic tonsils.

Transl Oncol 2021 Feb 24;14(2):101002. Epub 2020 Dec 24.

Department of Otorhinolaryngology, Head and Neck Surgery, Christian-Albrechts-University Kiel, Arnold-Heller-Str. 3, Building 27, D24105 Kiel, Germany. Electronic address:

Previous studies describe a correlation between HPV-positivity and non-smoking in TSCC; p16-expression as surrogate-marker for HPV-DNA/RNA-positivity is discussed controversially. In the present study, these parameters are assessed prospectively. HPV-status of sputum and tonsillar-swabs was analyzed to determine their validity as surrogate-marker for tissue-HPV-status. TSCC- (n = 52) and non-neoplastic tonsillar tissue (n = 163) were analyzed. HPV-DNA- and HPV-RNA-status of total sputum, cellular fraction and supernatants, tonsillar-swabs and -tissue was determined by (RT)-PCR. Immunohistochemistry determined p16-expression. 23/163 (14.2%) non-neoplastic tonsils were HPV-DNA-positive; five patients (3 HPV16, 2 HPV11) had active HPV-infections (HPV-RNA-positive), in all biomaterials. 140/163 (85.9%) patients were either HPV-DNA-positive or HPV-DNA-negative in all samples. 21/52 (40.4%) TSCC-tonsils were HPV-DNA-positive; 17 patients were HPV-RNA-positive (14 HPV16; 4 HPV18). 40/52 (76.9%) TSCC-patients were congruent in all biomaterials. p16-expression alone would have misclassified the HPV-status of 14/52 (26.2%) TSCC-patients. This prospective study confirms the discrepancy between HPV-status and p16-expression and the significant correlation between non-smoking and HPV-DNA-positivity. HPV-sputum- and/or swab-results do not consistently match tissue-results, possibly having (detrimental) consequences if those were used to assess tissue-HPV-status. In the 5 patients with active HPV infection in the non-neoplasitic tonsils, tonsillectomy likely prevented subsequent development of TSCC.
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http://dx.doi.org/10.1016/j.tranon.2020.101002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772224PMC
February 2021

A framework for modeling epistatic interaction.

Bioinformatics 2020 Nov 30. Epub 2020 Nov 30.

Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, Freising, Germany.

Motivation: Recently, various tools for detecting single nucleotide polymorphisms (SNPs) involved in epistasis have been developed. However, no studies evaluate the employed statistical epistasis models such as the χ2-test or quadratic regression independently of the tools that use them. Such an independent evaluation is crucial for developing improved epistasis detection tools, for it allows to decide if a tool's performance should be attributed to the epistasis model or to the optimization strategy run on top of it.

Results: We present a protocol for evaluating epistasis models independently of the tools they are used in and generalize existing models designed for dichotomous phenotypes to the categorical and quantitative case. Additionally, we propose a new model which scores candidate SNP sets by computing maximum likelihood distributions for the observed phenotypes in the cells of their penetrance tables. Extensive experiments show that the proposed maximum likelihood model outperforms three widely used epistasis models in most cases. The experiments also provide valuable insights into the properties of existing models, for instance, that quadratic regression perform particularly well on instances with quantitative phenotypes.

Availability And Implementation: The evaluation protocol and all compared models are implemented in C ++ and are supported under Linux and macOS. They are available at https://github.com/baumbachlab/genepiseeker/, along with test datasets and scripts to reproduce the experiments.

Supplementary Information: Supplementary information is available at Bioinformatics online.
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http://dx.doi.org/10.1093/bioinformatics/btaa990DOI Listing
November 2020

Pharmacological Inhibition of Acid Sphingomyelinase Prevents Uptake of SARS-CoV-2 by Epithelial Cells.

Cell Rep Med 2020 Nov 29;1(8):100142. Epub 2020 Oct 29.

Institute of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.

The acid sphingomyelinase/ceramide system plays an important role in bacterial and viral infections. Here, we report that either pharmacological inhibition of acid sphingomyelinase with amitriptyline, imipramine, fluoxetine, sertraline, escitalopram, or maprotiline or genetic downregulation of the enzyme prevents infection of cultured cells or freshy isolated human nasal epithelial cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or vesicular stomatitis virus (VSV) pseudoviral particles (pp-VSV) presenting SARS-CoV-2 spike protein (pp-VSV-SARS-CoV-2 spike), a bona fide system mimicking SARS-CoV-2 infection. Infection activates acid sphingomyelinase and triggers a release of ceramide on the cell surface. Neutralization or consumption of surface ceramide reduces infection with pp-VSV-SARS-CoV-2 spike. Treating volunteers with a low dose of amitriptyline prevents infection of freshly isolated nasal epithelial cells with pp-VSV-SARS-CoV-2 spike. The data justify clinical studies investigating whether amitriptyline, a safe drug used clinically for almost 60 years, or other antidepressants that functionally block acid sphingomyelinase prevent SARS-CoV-2 infection.
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http://dx.doi.org/10.1016/j.xcrm.2020.100142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598530PMC
November 2020

Low serum neutralizing anti-SARS-CoV-2 S antibody levels in mildly affected COVID-19 convalescent patients revealed by two different detection methods.

Cell Mol Immunol 2021 04 2;18(4):936-944. Epub 2020 Nov 2.

Institute of Immunology, Hannover Medical School, Hannover, Germany.

Neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into cells via surface-expressed angiotensin-converting enzyme 2 (ACE2). We used a surrogate virus neutralization test (sVNT) and SARS-CoV-2 S protein-pseudotyped vesicular stomatitis virus (VSV) vector-based neutralization assay (pVNT) to assess the degree to which serum antibodies from coronavirus disease 2019 (COVID-19) convalescent patients interfere with the binding of SARS-CoV-2 S to ACE2. Both tests revealed neutralizing anti-SARS-CoV-2 S antibodies in the sera of ~90% of mildly and 100% of severely affected COVID-19 convalescent patients. Importantly, sVNT and pVNT results correlated strongly with each other and to the levels of anti-SARS-CoV-2 S1 IgG and IgA antibodies. Moreover, levels of neutralizing antibodies correlated with the duration and severity of clinical symptoms but not with patient age. Compared to pVNT, sVNT is less sophisticated and does not require any biosafety labs. Since this assay is also much faster and cheaper, sVNT will not only be important for evaluating the prevalence of neutralizing antibodies in a population but also for identifying promising plasma donors for successful passive antibody therapy.
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http://dx.doi.org/10.1038/s41423-020-00573-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604543PMC
April 2021

Success of minimally invasive salivary gland surgery-Quality of life, prognostic factors.

Laryngoscope Investig Otolaryngol 2020 Oct 1;5(5):832-838. Epub 2020 Sep 1.

Department of Otorhinolaryngology, Head and Neck Surgery University of Kiel Kiel Germany.

Objective: Goal of this study was to investigate, whether sialendoscopy in obstructive salivary gland disorders affects patients' oral health-related quality of life compared to healthy individuals, and to determine factors that might influence this relationship.

Study Design: Retrospective observational study.

Setting: University of Kiel, Department of Otorhinolaryngology, Head and Neck Surgery.

Subjects And Methods: A group of 130 patients, undergoing sialendoscopy between 01/2004 and 06/2017 was considered. Oral health-related quality of life was assessed using the OHIP-G14 (Oral Health Impact Profile) in combination with a custom-made questionnaire on satisfaction and success in relation to sialendoscopy.

Results: Oral health-related quality of life of patients without dentures or with removable dentures was significantly worse than in the healthy population, whereas the necessity of multiple additional follow-up treatments was associated with worse oral health-related quality of life. No essential predisposing factors were identified. Average satisfaction with the intervention was observed to be x̅ = 4.33 (SD = 3.69) on a visual analogue scale from 1 (=very satisfied) to 10 (=very unsatisfied). A longer follow-up period and a higher patients' age were positively related, whereas removal of salivary gland during follow-up was negatively related to satisfaction. In 113 cases (86.9%) long-term preservation was accomplished and 115 (88.5%) patients would repeat a sialendoscopy in case needed.

Conclusion: In summary, sialendoscopy resulted in long-term high subjective and objective success rates. However, oral health-related quality of life scores did not reach those levels found in the healthy population.
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http://dx.doi.org/10.1002/lio2.450DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7585237PMC
October 2020

Rapid response flow cytometric assay for the detection of antibody responses to SARS-CoV-2.

Eur J Clin Microbiol Infect Dis 2021 Apr 20;40(4):751-759. Epub 2020 Oct 20.

Institute of Clinical and Molecular Virology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.

SARS-CoV-2 has emerged as a previously unknown zoonotic coronavirus that spread worldwide causing a serious pandemic. While reliable nucleic acid-based diagnostic assays were rapidly available, only a limited number of validated serological assays were available in the early phase of the pandemic. Here, we evaluated a novel flow cytometric approach to assess spike-specific antibody responses.HEK 293T cells expressing SARS-CoV-2 spike protein in its natural confirmation on the surface were used to detect specific IgG and IgM antibody responses in patient sera by flow cytometry. A soluble angiotensin-converting-enzyme 2 (ACE-2) variant was developed as external standard to quantify spike-specific antibody responses on different assay platforms. Analyses of 201 pre-COVID-19 sera proved a high assay specificity in comparison to commercially available CLIA and ELISA systems, while also revealing the highest sensitivity in specimens from PCR-confirmed SARS-CoV-2-infected patients. The external standard allowed robust quantification of antibody responses among different assay platforms. In conclusion, our newly established flow cytometric assay allows sensitive and quantitative detection of SARS-CoV-2-specific antibodies, which can be easily adopted in different laboratories and does not rely on external supply of assay kits. The flow cytometric assay also provides a blueprint for rapid development of serological tests to other emerging viral infections.
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http://dx.doi.org/10.1007/s10096-020-04072-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7572153PMC
April 2021

No association between HPV-status in tonsillar tissue and sexual behavior of the patients in a northern German population - Critical view of the link between HPV natural history and HPV-driven carcinogenesis.

Papillomavirus Res 2020 12 21;10:100207. Epub 2020 Sep 21.

Department of Otorhinolaryngology, Head and Neck Surgery, Christian-Albrechts-University, Arnold-Heller-Str. 3, Building 27, D-24105, Kiel, Germany. Electronic address:

HPV-infection in patients with HNSCC is reportedly correlated with sexual behavior, age, and tobacco/alcohol-consumption. HPV-infections of the oral cavity are regarded as sexually transmitted. Comparable data of patient populations outside the U.S. are sparse or missing. Questionnaires regarding sexual behavior, education tobacco- and alcohol-consumption, were given to 28 patients with tonsillar hyperplasia (H) and 128 patients with tonsillar carcinomas (CA), all with tissue-typed HPV-DNA-status performing PCR. Answers were correlated among groups and HPV-status. 106 questionnaires were analyzed. Comparisons between H- (n = 25) and CA- (n = 81) patients showed that CA-patients were older (61.1yrs ± 9.3) than H-patients (45.2yrs ± 11.9; p < 0.0001; Student's t-test); had a lower educational level (p = 0.0095); and lower number of sexual partners (p = 0.0222; Fisher's exact test). All groups showed a significant correlation between smoking and lack of HPV-DNA-positivity (p = 0.001). Further Fisher's exact tests and logistic regression analysis revealed in all 106 patients no significant correlations between tissue-HPV-status and the analyzed parameters. Despite the limited sample size, we were able to confirm the established correlation between smoking and tissue-HPV-status. The correlation between sexual behavior and HPV-infection was not confirmed. No consensus exists in the literature about the latter. Our data does not support the strict classification of oral HPV-infections and HPV-driven HNSCCs as STDs.
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http://dx.doi.org/10.1016/j.pvr.2020.100207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7554645PMC
December 2020

Breakdown of the Stokes-Einstein Equation for Solutions of Water in Oil Reverse Micelles.

J Phys Chem B 2020 Oct 2;124(41):9115-9125. Epub 2020 Oct 2.

Institute of Physical Chemistry, Technical University Darmstadt, Alarich-Weiss-Straße 8, Darmstadt D-64287, Germany.

An experimental study is presented for the reverse micellar system of 15% by mass polydisperse hexaethylene glycol monodecylether (CE) in cyclohexane with varying amounts of added water up to 4% by mass. Measurements of viscosity and self-diffusion coefficients were taken as a function of temperature between 10 and 45 °C at varying sample water loads but fixed CE/cyclohexane composition. The results were used to inspect the validity of the Stokes-Einstein equation for this system. Unreasonably small reverse average micelle radii and aggregation numbers were obtained with the Stokes-Einstein equation, but reasonable values for these quantities were obtained using the ratio of surfactant-to-cyclohexane self-diffusion coefficients. While bulk viscosity increased with increasing water load, a concurrent expected decrease of self-diffusion coefficient was only observed for the surfactant and water but not for cyclohexane, which showed independence of water load. Moreover, a spread of self-diffusion coefficients was observed for the protons associated with the ethylene oxide repeat unit in samples with polydisperse CE but not in a sample with monodisperse CE. These findings were interpreted by the presence of reverse micelle to reverse micelle hopping motions that with higher water load become increasingly selective toward CE molecules with short ethylene oxide repeat units, while those with long ethylene oxide repeat units remain trapped within the reverse micelle because of the increased hydrogen bonding interactions with the water inside the growing core of the reverse micelle. Despite the observed breakdown of the Stokes-Einstein equation, the temperature dependence of the viscosities and self-diffusion coefficients was found to follow Arrhenius behavior over the investigated range of temperatures.
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http://dx.doi.org/10.1021/acs.jpcb.0c06124DOI Listing
October 2020

Sphingosine prevents binding of SARS-CoV-2 spike to its cellular receptor ACE2.

J Biol Chem 2020 11 11;295(45):15174-15182. Epub 2020 Sep 11.

Department of Surgery, University of Cincinnati Medical School, Cincinnati, Ohio, USA; Institute of Molecular Biology, University of Duisburg-Essen, Essen, Germany. Electronic address:

Sphingosine has been shown to prevent and eliminate bacterial infections of the respiratory tract, but it is unknown whether sphingosine can be also employed to prevent viral infections. To test this hypothesis, we analyzed whether sphingosine regulates the infection of cultured and freshly isolated human epithelial cells with pseudoviral particles expressing SARS-CoV-2 spike (pp-VSV-SARS-CoV-2 spike) that served as a system mimicking SARS-CoV-2 infection. We demonstrate that exogenously applied sphingosine suspended in 0.9% NaCl prevents cellular infection with pp-SARS-CoV-2 spike. Pretreatment of cultured Vero epithelial cells or freshly isolated human nasal epithelial cells with low concentrations of sphingosine prevented adhesion of and infection with pp-VSV-SARS-CoV-2 spike. Mechanistically, we demonstrate that sphingosine binds to ACE2, the cellular receptor of SARS-CoV-2, and prevents the interaction of the receptor-binding domain of the viral spike protein with ACE2. These data indicate that sphingosine prevents at least some viral infections by interfering with the interaction of the virus with its receptor. Our data also suggest that further preclinical and finally clinical examination of sphingosine is warranted for potential use as a prophylactic or early treatment for coronavirus disease-19.
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http://dx.doi.org/10.1074/jbc.RA120.015249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7650243PMC
November 2020

The Amino Acid at Position 8 of the Proteolytic Cleavage Site of the Mumps Virus Fusion Protein Affects Viral Proteolysis and Fusogenicity.

J Virol 2020 10 27;94(22). Epub 2020 Oct 27.

Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany

The mumps virus (MuV) fusion protein (F) plays a crucial role for the entry process and spread of infection by mediating fusion between viral and cellular membranes as well as between infected and neighboring cells, respectively. The fusogenicity of MuV differs depending on the strain and might correlate with the virulence; however, it is unclear which mechanisms contribute to the differentiated fusogenicity. The cleavage motif of MuV F is highly conserved among all strains, except the amino acid residue at position 8 (P8) that shows a certain variability with a total of four amino acid variants (leucine [L], proline [P], serine [S], and threonine [T]). We demonstrate that P8 affects the proteolytic processing and the fusogenicity of MuV F. The presence of L or S at P8 resulted in a slower proteolysis of MuV F by furin and a reduced ability to mediate cell-cell fusion. However, virus-cell fusion was more efficient for F proteins harboring L or S at P8, suggesting that P8 contributes to the mechanism of viral spread: P and T enable a rapid spread of infection by cell-to-cell fusion, whereas viruses harboring L or S at P8 spread preferentially by the release of infectious viral particles. Our study provides novel insights into the fusogenicity of MuV and its influence on the mechanisms of virus spread within infected tissues. Assuming a correlation between MuV fusogenicity and virulence, sequence information on the amino acid residue at P8 might be helpful to estimate the virulence of circulating and emerging strains. Mumps virus (MuV) is the causative agent of the highly infectious disease mumps. Mumps is mainly associated with mild symptoms, but severe complications such as encephalitis, meningitis, or orchitis can also occur. There is evidence that the virulence of different MuV strains and variants might correlate with the ability of the fusion protein (F) to mediate cell-to-cell fusion. However, the relation between virulence and fusogenicity or the mechanisms responsible for the varied fusogenicity of different MuV strains are incompletely understood. Here, we focused on the amino acid residue at position 8 (P8) of the proteolytic cleavage site of MuV F, because this amino acid residue shows a striking variability depending on the genotype of MuV. The P8 residue has a significant effect on the proteolytic processing and fusogenicity of MuV F and might thereby determine the route of viral spread within infected tissues.
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http://dx.doi.org/10.1128/JVI.01732-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7592220PMC
October 2020

Alteration of smoking habit at time of first diagnosis influences survival of patients with HNSCC.

Mol Clin Oncol 2020 Nov 20;13(5):50. Epub 2020 Aug 20.

Department of Otorhinolaryngology, Head and Neck Surgery, Christian-Albrechts-University, University Hospital Schleswig-Holstein, D-24105 Kiel, Germany.

The impact of smoking on survival in patients with squamous cell carcinoma of the head and neck is well established, despite some conflicting data in the literature. However, data on alterations of smoking habit following cancer diagnosis is sparse. In the present study, the effect of reduction of smoking compared with cessation on the course of disease was studied. Data from 643 patients with HNSCC from the tumor documentation registry of the Department of Otorhinolaryngology, Head and Neck Surgery of the Christian-Albrechts-University Kiel were collected and statistically analyzed, looking at pre- and post-treatment smoking habit and survival. Alteration of smoking at the first diagnosis of HNSCC led to a significantly beneficial effect on survival outcomes compared with continued smoking, without significant differences between reduction and cessation of smoking. Detailed analysis revealed that this effect was solely dependent on patients treated by surgery only. Lifelong non-smokers exhibited a significant survival advantage compared with active and former smokers, with no difference in survival between these last two groups. The positive influence of altered smoking habit following first time diagnosis on disease-specific survival paralleled the negative direct effect of active smoking on therapy, which is predominantly attributed to peritumoral tissue hypoxia leading to impaired efficacy of radiochemotherapy (RCT). In the present study cohort, the positive effect of smoking habit alterations were primarily observed in patients treated by surgery only instead of RCT, possibly due to fewer perioperative complications. These findings indicated that patients should be encouraged to at least minimize smoking following cancer diagnosis. Furthermore, for survival estimates and therapy planning, former smokers should be considered as active smokers.
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http://dx.doi.org/10.3892/mco.2020.2120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7453390PMC
November 2020

Large Dzyaloshinskii-Moriya interaction induced by chemisorbed oxygen on a ferromagnet surface.

Sci Adv 2020 Aug 14;6(33):eaba4924. Epub 2020 Aug 14.

Physics Department, University of California, Davis, CA 95616, USA.

The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction that stabilizes chiral spin textures. It is induced by inversion symmetry breaking in noncentrosymmetric lattices or at interfaces. Recently, interfacial DMI has been found in magnetic layers adjacent to transition metals due to the spin-orbit coupling and at interfaces with graphene due to the Rashba effect. We report direct observation of strong DMI induced by chemisorption of oxygen on a ferromagnetic layer at room temperature. The sign of this DMI and its unexpectedly large magnitude-despite the low atomic number of oxygen-are derived by examining the oxygen coverage-dependent evolution of magnetic chirality. We find that DMI at the oxygen/ferromagnet interface is comparable to those at ferromagnet/transition metal interfaces; it has enabled direct tailoring of skyrmion's winding number at room temperature via oxygen chemisorption. This result extends the understanding of the DMI, opening up opportunities for the chemisorption-related design of spin-orbitronic devices.
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http://dx.doi.org/10.1126/sciadv.aba4924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428341PMC
August 2020

Camostat mesylate inhibits SARS-CoV-2 activation by TMPRSS2-related proteases and its metabolite GBPA exerts antiviral activity.

bioRxiv 2020 Aug 5. Epub 2020 Aug 5.

Infection Biology Unit, German Primate Center - Leibniz Institute for Primate Research, 37077 Göttingen, Germany.

Antiviral therapy is urgently needed to combat the coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The protease inhibitor camostat mesylate inhibits SARS-CoV-2 infection of lung cells by blocking the virus-activating host cell protease TMPRSS2. Camostat mesylate has been approved for treatment of pancreatitis in Japan and is currently being repurposed for COVID-19 treatment. However, potential mechanisms of viral resistance as well as camostat mesylate metabolization and antiviral activity of metabolites are unclear. Here, we show that SARS-CoV-2 can employ TMPRSS2-related host cell proteases for activation and that several of them are expressed in viral target cells. However, entry mediated by these proteases was blocked by camostat mesylate. The camostat metabolite GBPA inhibited the activity of recombinant TMPRSS2 with reduced efficiency as compared to camostat mesylate and was rapidly generated in the presence of serum. Importantly, the infection experiments in which camostat mesylate was identified as a SARS-CoV-2 inhibitor involved preincubation of target cells with camostat mesylate in the presence of serum for 2 h and thus allowed conversion of camostat mesylate into GBPA. Indeed, when the antiviral activities of GBPA and camostat mesylate were compared in this setting, no major differences were identified. Our results indicate that use of TMPRSS2-related proteases for entry into target cells will not render SARS-CoV-2 camostat mesylate resistant. Moreover, the present and previous findings suggest that the peak concentrations of GBPA established after the clinically approved camostat mesylate dose (600 mg/day) will result in antiviral activity.
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http://dx.doi.org/10.1101/2020.08.05.237651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418737PMC
August 2020

Myeloperoxidase Modulates Inflammation in Generalized Pustular Psoriasis and Additional Rare Pustular Skin Diseases.

Am J Hum Genet 2020 09 5;107(3):527-538. Epub 2020 Aug 5.

Department of Dermatology, University of Bonn, Bonn 53127, Germany.

Generalized pustular psoriasis (GPP) is a severe multi-systemic inflammatory disease characterized by neutrophilic pustulosis and triggered by pro-inflammatory IL-36 cytokines in skin. While 19%-41% of affected individuals harbor bi-allelic mutations in IL36RN, the genetic cause is not known in most cases. To identify and characterize new pathways involved in the pathogenesis of GPP, we performed whole-exome sequencing in 31 individuals with GPP and demonstrated effects of mutations in MPO encoding the neutrophilic enzyme myeloperoxidase (MPO). We discovered eight MPO mutations resulting in MPO -deficiency in neutrophils and monocytes. MPO mutations, primarily those resulting in complete MPO deficiency, cumulatively associated with GPP (p = 1.85E-08; OR = 6.47). The number of mutant MPO alleles significantly differed between 82 affected individuals and >4,900 control subjects (p = 1.04E-09); this effect was stronger when including IL36RN mutations (1.48E-13) and correlated with a younger age of onset (p = 0.0018). The activity of four proteases, previously implicated as activating enzymes of IL-36 precursors, correlated with MPO deficiency. Phorbol-myristate-acetate-induced formation of neutrophil extracellular traps (NETs) was reduced in affected cells (p = 0.015), and phagocytosis assays in MPO-deficient mice and human cells revealed altered neutrophil function and impaired clearance of neutrophils by monocytes (efferocytosis) allowing prolonged neutrophil persistence in inflammatory skin. MPO mutations contribute significantly to GPP's pathogenesis. We implicate MPO as an inflammatory modulator in humans that regulates protease activity and NET formation and modifies efferocytosis. Our findings indicate possible implications for the application of MPO inhibitors in cardiovascular diseases. MPO and affected pathways represent attractive targets for inducing resolution of inflammation in neutrophil-mediated skin diseases.
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http://dx.doi.org/10.1016/j.ajhg.2020.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7477008PMC
September 2020

LY6E impairs coronavirus fusion and confers immune control of viral disease.

Nat Microbiol 2020 11 23;5(11):1330-1339. Epub 2020 Jul 23.

Institute of Virology and Immunology, Bern, Switzerland.

Zoonotic coronaviruses (CoVs) are substantial threats to global health, as exemplified by the emergence of two severe acute respiratory syndrome CoVs (SARS-CoV and SARS-CoV-2) and Middle East respiratory syndrome CoV (MERS-CoV) within two decades. Host immune responses to CoVs are complex and regulated in part through antiviral interferons. However, interferon-stimulated gene products that inhibit CoVs are not well characterized. Here, we show that lymphocyte antigen 6 complex, locus E (LY6E) potently restricts infection by multiple CoVs, including SARS-CoV, SARS-CoV-2 and MERS-CoV. Mechanistic studies revealed that LY6E inhibits CoV entry into cells by interfering with spike protein-mediated membrane fusion. Importantly, mice lacking Ly6e in immune cells were highly susceptible to a murine CoV-mouse hepatitis virus. Exacerbated viral pathogenesis in Ly6e knockout mice was accompanied by loss of hepatic immune cells, higher splenic viral burden and reduction in global antiviral gene pathways. Accordingly, we found that constitutive Ly6e directly protects primary B cells from murine CoV infection. Our results show that LY6E is a critical antiviral immune effector that controls CoV infection and pathogenesis. These findings advance our understanding of immune-mediated control of CoV in vitro and in vivo-knowledge that could help inform strategies to combat infection by emerging CoVs.
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http://dx.doi.org/10.1038/s41564-020-0769-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916999PMC
November 2020

Chloroquine does not inhibit infection of human lung cells with SARS-CoV-2.

Nature 2020 09 22;585(7826):588-590. Epub 2020 Jul 22.

Infection Biology Unit, German Primate Center - Leibniz Institute for Primate Research, Göttingen, Germany.

The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been associated with more than 780,000 deaths worldwide (as of 20 August 2020). To develop antiviral interventions quickly, drugs used for the treatment of unrelated diseases are currently being repurposed to treat COVID-19. Chloroquine is an anti-malaria drug that is used for the treatment of COVID-19 as it inhibits the spread of SARS-CoV-2 in the African green monkey kidney-derived cell line Vero. Here we show that engineered expression of TMPRSS2, a cellular protease that activates SARS-CoV-2 for entry into lung cells, renders SARS-CoV-2 infection of Vero cells insensitive to chloroquine. Moreover, we report that chloroquine does not block infection with SARS-CoV-2 in the TMPRSS2-expressing human lung cell line Calu-3. These results indicate that chloroquine targets a pathway for viral activation that is not active in lung cells and is unlikely to protect against the spread of SARS-CoV-2 in and between patients.
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http://dx.doi.org/10.1038/s41586-020-2575-3DOI Listing
September 2020