Dr.

Burger-Kentischer, Anke

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  • Publication
    Computationally designed bispecific MD2/CD14 binding peptides show TLR4 agonist activity
    ( 2018)
    Michaeli, Amit
    ;
    Mezan, Shaul
    ;
    Kühbacher, Andreas
    ;
    Finkelmeier, Doris
    ;
    Elias, Maayan
    ;
    Zatsepin, Maria
    ;
    Reed, Steven G.
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    Duthie, Malcolm S.
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    Rupp, Steffen
    ;
    Lerner, Immanuel
    ;
    Burger-Kentischer, Anke
    Toll-like receptor 4 plays an important role in the regulation of the innate and adaptive immune response. The majority of TLR4 activators currently in clinical use are derivatives of its prototypic ligand LPS. The discovery of innovative TLR4 activators has the potential of providing new therapeutic immunomodulators and adjuvants. We used computational design methods to predict and optimize a total of 53 cyclic and linear peptides targeting myeloid differentiation 2 (MD2) and cluster of differentiation 14 (CD14), both coreceptors of human TLR4. Activity of the designed peptides was first assessed using NF-kB reporter cell lines expressing either TLR4/MD2 or TLR4/CD14 receptors, then binding to CD14 and MD2 confirmed and quantified using MicroScale Thermophoresis. Finally, we incubated select peptides in human whole blood and observed their ability to induce cytokine production, either alone or in synergy with LPS. Our data demonstrate the advantage of computational design for the discovery of new TLR4 peptide activators with little structural resemblance to known ligands and indicate an efficient strategy with which to identify TLR4 targeting peptides that could be used as easy-to-produce alternatives to LPS-derived molecules in a variety of settings.
  • Publication
    Interaction of Candida Species with the Skin
    ( 2017)
    Kühbacher, Andreas
    ;
    Burger-Kentischer, A.
    ;
    Rupp, S.
    The human skin is commonly colonized by diverse fungal species. Some Candida species, especially C. albicans, do not only reside on the skin surface as commensals, but also cause infections by growing into the colonized tissue. However, defense mechanisms at the skin barrier level are very efficient, involving residential non-immune and immune cells as well as immune cells specifically recruited to the site of infection. Therefore, the skin is an effective barrier against fungal infection. While most studies about commensal and pathogenic interaction of Candida species with host epithelia focus on the interaction with mucosal surfaces such as the vaginal and gastrointestinal epithelia, less is known about the mechanisms underlying Candida interaction with the skin. In this review, we focus on the ecology and molecular pathogenesis of Candida species on the skin and give an overview of defense mechanisms against C. albicans in this context. We also discuss new research avenues in dermal infection, including the involvement of neurons, fibroblasts, and commensal bacteria in both mouse and human model systems.
  • Publication
    Central role for dermal fibroblasts in skin model protection against Candida albicans
    ( 2017)
    Kühbacher, Andreas
    ;
    Henkel, H.
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    Stevens, Philip
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    Grumaz, Christian
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    Finkelmeier, D.
    ;
    Burger-Kentischer, A.
    ;
    Sohn, K.
    ;
    Rupp, S.
    The fungal pathogen Candida albicans colonizes basically all human epithelial surfaces, including the skin. Under certain conditions, such as immunosuppression, invasion of the epithelia occurs. Not much is known about defense mechanisms against C. albicans in subepithelial layers such as the dermis. Using immune cell-supplemented 3D skin models we defined a new role for fibroblasts in the dermis and identified a minimal set of cell types for skin protection against C. albicans invasion. Dual RNA sequencing of individual host cell populations and C. albicans revealed that dermal invasion is directly impeded by dermal fibroblasts. They are able to integrate signals from the pathogen and CD4+ T cells and shift toward an antimicrobial phenotype with broad specificity that is dependent on Toll-like receptor 2 and interleukin 1β. These results highlight a central function of dermal fibroblasts for skin protection, opening new possibilities for treatment of infectious diseases.
  • Publication
    Immune cell-supplemented human skin model for studying fungal infections
    ( 2017)
    Kühbacher, Andreas
    ;
    Sohn, Kai
    ;
    Burger-Kentischer, Anke
    ;
    Rupp, Steffen
    Human skin is a niche for various fungal species which either colonize the surface of this tissue as commensals or, primarily under conditions of immunosuppression, invade the skin and cause infection. Here we present a method for generation of a human in vitro skin model supplemented with immune cells of choice. This model represents a complex yet amenable tool to study molecular mechanisms of host-fungi interactions at human skin.
  • Publication
    Reduced cytotoxicity and enhanced bioactivity of cationic antimicrobial peptides liposomes in cell cultures and 3D epidermis model against HSV
    ( 2016)
    Ron-Doitch, Sapir
    ;
    Sawodny, Beate
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    Kühbacher, Andreas
    ;
    Nordling, Mirjam M.
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    Samanta, Ayan
    ;
    Phopase, Jaywant
    ;
    Burger-Kentischer, Anke
    ;
    Griffith, May
    ;
    Golomb, Gershon
    ;
    Rupp, Steffen
    Cationic antimicrobial peptides (AMPs) are part of the innate immunity, and act against a wide variety of pathogenic microorganisms by perturbation of the microorganism's plasma membrane. Although attractive for clinical applications, these agents suffer from limited stability and activity in vivo, as well as non-specific interaction with host biological membranes, leading to cytotoxic adverse effects. We hypothesized that encapsulation of AMPs within liposomes could result in reduced cytotoxicity, and with enhanced stability as well as bioactivity against herpes simplex virus 1 (HSV-1). We formulated nano-sized liposomal formulations of LL-37 and indolicidin, and their physicochemical properties, cellular uptake, in vitro cytotoxicity and antiviral efficacy have been determined. Lower cytotoxicity of LL-37 liposomes was found in comparison to indolicidin liposomes attributed to the superior physicochemical properties, and to the different degree of interaction with the liposomal membrane. The disc-like shaped LL-37 liposomes (106.8 ± 10.1 nm, shelf-life stability of >1 year) were taken up more rapidly and to a significantly higher extent than the free peptide by human keratinocyte cell line (HaCaT), remained intact within the cells, followed by release of the active peptide within the cytoplasm and migration of the vesicles' lipids to the plasma membrane. LL-37 liposomes were found significantly less toxic than both the free agent and liposomal indolicidin. In the new 3D epidermis model (immortalized primary keratinocytes) liposomal LL-37 treatment (>20 mM), but not free LL-37, efficiently protected the epidermis, inhibiting HSV-1 infection. This positive antiviral effect was obtained with no cytotoxicity even at very high concentrations (400 mM). Thus, the antiviral activity of encapsulated LL-37 was significantly improved, expanding its therapeutic window. Liposomal LL-37 appears to be a promising delivery system for HSV therapy.