TY - JOUR A1 - Dasari, Prasad A1 - Koleci, Naile A1 - Shopova, Iordana A. A1 - Wartenberg, Dirk A1 - Beyersdorf, Niklas A1 - Dietrich, Stefanie A1 - Sahagún-Ruiz, Alfredo A1 - Figge, Marc Thilo A1 - Skerka, Christine A1 - Brakhage, Axel A. A1 - Zipfel, Peter F. T1 - Enolase from Aspergillus fumigatus is a moonlighting protein that binds the human plasma complement proteins factor H, FHL-1, C4BP, and plasminogen JF - Frontiers in Immunology N2 - The opportunistic fungal pathogen Aspergillus fumigatus can cause severe infections, particularly in immunocompromised individuals. Upon infection, A. fumigatus faces the powerful and directly acting immune defense of the human host. The mechanisms on how A. fumigatus evades innate immune attack and complement are still poorly understood. Here, we identify A. fumigatus enolase, AfEno1, which was also characterized as fungal allergen, as a surface ligand for human plasma complement regulators. AfEno1 binds factor H, factor-H-like protein 1 (FHL-1), C4b binding protein (C4BP), and plasminogen. Factor H attaches to AfEno1 via two regions, via short conserved repeats (SCRs) 6–7 and 19–20, and FHL-1 contacts AfEno1 via SCRs 6–7. Both regulators when bound to AfEno1 retain cofactor activity and assist in C3b inactivation. Similarly, the classical pathway regulator C4BP binds to AfEno1 and bound to AfEno1; C4BP assists in C4b inactivation. Plasminogen which binds to AfEno1 via lysine residues is accessible for the tissue-type plasminogen activator (tPA), and active plasmin cleaves the chromogenic substrate S2251, degrades fibrinogen, and inactivates C3 and C3b. Plasmin attached to swollen A. fumigatus conidia damages human A549 lung epithelial cells, reduces the cellular metabolic activity, and induces cell retraction, which results in exposure of the extracellular matrix. Thus, A. fumigatus AfEno1 is a moonlighting protein and virulence factor which recruits several human regulators. The attached human regulators allow the fungal pathogen to control complement at the level of C3 and to damage endothelial cell layers and tissue components. KW - complement factor H KW - moonlighting KW - immune evasion KW - plasminogen KW - blocking phagocytosis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-195612 SN - 1664-3224 VL - 10 ER - TY - JOUR A1 - Dasari, Prasad A1 - Shopova, Iordana A. A1 - Stroe, Maria A1 - Wartenberg, Dirk A1 - Martin-Dahse, Hans A1 - Beyersdorf, Niklas A1 - Hortschansky, Peter A1 - Dietrich, Stefanie A1 - Cseresnyés, Zoltán A1 - Figge, Marc Thilo A1 - Westermann, Martin A1 - Skerka, Christine A1 - Brakhage, Axel A. A1 - Zipfel, Peter F. T1 - Aspf2 From Aspergillus fumigatus Recruits Human Immune Regulators for Immune Evasion and Cell Damage JF - Frontiers in Immunology N2 - The opportunistic fungal pathogen Aspergillus fumigatus can cause life-threatening infections, particularly in immunocompromised patients. Most pathogenic microbes control host innate immune responses at the earliest time, already before infiltrating host immune cells arrive at the site of infection. Here, we identify Aspf2 as the first A. fumigatus Factor H-binding protein. Aspf2 recruits several human plasma regulators, Factor H, factor-H-like protein 1 (FHL-1), FHR1, and plasminogen. Factor H contacts Aspf2 via two regions located in SCRs6–7 and SCR20. FHL-1 binds via SCRs6–7, and FHR1 via SCRs3–5. Factor H and FHL-1 attached to Aspf2-maintained cofactor activity and assisted in C3b inactivation. A Δaspf2 knockout strain was generated which bound Factor H with 28% and FHL-1 with 42% lower intensity. In agreement with less immune regulator acquisition, when challenged with complement-active normal human serum, Δaspf2 conidia had substantially more C3b (>57%) deposited on their surface. Consequently, Δaspf2 conidia were more efficiently phagocytosed (>20%) and killed (44%) by human neutrophils as wild-type conidia. Furthermore, Aspf2 recruited human plasminogen and, when activated by tissue-type plasminogen activator, newly generated plasmin cleaved the chromogenic substrate S2251 and degraded fibrinogen. Furthermore, plasmin attached to conidia damaged human lung epithelial cells, induced cell retraction, and caused matrix exposure. Thus, Aspf2 is a central immune evasion protein and plasminogen ligand of A. fumigatus. By blocking host innate immune attack and by disrupting human lung epithelial cell layers, Aspf2 assists in early steps of fungal infection and likely allows tissue penetration. KW - complement KW - blocking opsonization KW - phagocytosis KW - acquisition of host regulators KW - immune evasion Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197013 SN - 1664-3224 VL - 9 IS - 1635 ER - TY - JOUR A1 - Dühring, Sybille A1 - Germerodt, Sebastian A1 - Skerka, Christine A1 - Zipfel, Peter F. A1 - Dandekar, Thomas A1 - Schuster, Stefan T1 - Host-pathogen interactions between the human innate immune system and Candida albicans - understanding and modeling defense and evasion strategies JF - Frontiers in Microbiology N2 - The diploid, polymorphic yeast Candida albicans is one of the most important human pathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within the human host for a long time. However, alterations in the host environment can render C. albicans virulent. In this review, we describe the immunological cross-talk between C. albicans and the human innate immune system. We give an overview in form of pairs of human defense strategies including immunological mechanisms as well as general stressors such as nutrient limitation, pH, fever etc. and the corresponding fungal response and evasion mechanisms. Furthermore, Computational Systems Biology approaches to model and investigate these complex interactions are highlighted with a special focus on game-theoretical methods and agent-based models. An outlook on interesting questions to be tackled by Systems Biology regarding entangled defense and evasion mechanisms is given. KW - agent-based model KW - antimicrobial peptides KW - fungal pathogens KW - Candida albicans KW - immunological cross-talk KW - beta-lactamase inhibition KW - in vitro KW - biomaterial surfaces KW - biofilm formation KW - dendritic cells KW - infection KW - resistance KW - human immune system KW - host-pathogen interaction KW - computational systems biology KW - defense and evasion strategies Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151621 VL - 6 IS - 625 ER - TY - JOUR A1 - Halder, Luke D. A1 - Abdelfatah, Mahmoud A. A1 - Jo, Emeraldo A. H. A1 - Jacobsen, Ilse D. A1 - Westermann, Martin A1 - Beyersdorf, Niklas A1 - Lorkowski, Stefan A1 - Zipfel, Peter F. A1 - Skerka, Christine T1 - Factor H binds to extracellular DNA traps released from human blood monocytes in response to Candida albicans JF - Frontiers in Immunology N2 - Upon systemic infection with human pathogenic yeast Candida albicans (C. albicans), human monocytes and polymorph nuclear neutrophilic granulocytes are the first immune cells to respond and come into contact with C. albicans. Monocytes exert immediate candidacidal activity and inhibit germination, mediate phagocytosis, and kill fungal cells. Here, we show that human monocytes spontaneously respond to C. albicans cells via phagocytosis, decondensation of nuclear DNA, and release of this decondensed DNA in the form of extracellular traps (called monocytic extracellular traps: MoETs). Both subtypes of monocytes (CD14\(^{++}\)CD16\(^−\)/CD14\(^+\)CD16\(^+\)) formed MoETs within the first hours upon contact with C. albicans. MoETs were characterized by the presence of citrullinated histone, myeloperoxidase, lactoferrin, and elastase. MoETs were also formed in response to Staphylococcus aureus and Escherichia coli, indicating a general reaction of monocytes to infectious microbes. MoET induction differs from extracellular trap formation in macrophages as MoETs are not triggered by simvastatin, an inhibitor of cholesterol synthesis and inducer of extracellular traps in macrophages. Extracellular traps from both monocytes and neutrophils activate complement and C3b is deposited. However, factor H (FH) binds via C3b to the extracellular DNA, mediates cofactor activity, and inhibits the induction of the inflammatory cytokine interleukin-1 beta in monocytes. Altogether, the results show that human monocytes release extracellular DNA traps in response to C. albicans and that these traps finally bind FH via C3b to presumably support clearance without further inflammation. KW - Candida KW - monocytes KW - DNA traps KW - MPO KW - factor H Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181127 VL - 7 ER -