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Liu Q, Mazhar M, Miller LS. Immune and Inflammatory Reponses to Staphylococcus aureus Skin Infections. CURRENT DERMATOLOGY REPORTS 2018; 7:338-349. [PMID: 30989002 DOI: 10.1007/s13671-018-0235-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Purpose of Review There have been recent advances in our understanding of cutaneous immune responses to the important human skin pathogen, Staphylococcus aureus (S. aureus). This review will highlight these insights into innate and adaptive immune mechanisms in host defense and cutaneous inflammation in response to S. aureus skin infections. Recent Findings Antimicrobial peptides, pattern recognition receptors and inflammasome activation function in innate immunity as well as T cells and their effector cytokines play a key role in adaptive immunity against S. aureus skin infections. In addition, certain mechanisms by which S. aureus contributes to aberrant cutaneous inflammation, such as in flares of the inflammatory skin disease atopic dermatitis have also been identified. Summary These cutaneous immune mechanisms could provide new targets for future vaccines and immune-based therapies to combat skin infections and cutaneous inflammation caused by S. aureus.
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Affiliation(s)
- Qi Liu
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Momina Mazhar
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Lloyd S Miller
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
- Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
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Askarian F, Wagner T, Johannessen M, Nizet V. Staphylococcus aureus modulation of innate immune responses through Toll-like (TLR), (NOD)-like (NLR) and C-type lectin (CLR) receptors. FEMS Microbiol Rev 2018; 42:656-671. [PMID: 29893825 PMCID: PMC6098222 DOI: 10.1093/femsre/fuy025] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 06/07/2018] [Indexed: 02/07/2023] Open
Abstract
Early recognition of pathogens by the innate immune system is crucial for bacterial clearance. Many pattern recognition receptors (PRRs) such as Toll-like (TLRs) and (NOD)-like (NLRs) receptors have been implicated in initial sensing of bacterial components. The intracellular signaling cascades triggered by these receptors result in transcriptional upregulation of inflammatory pathways. Although this step is crucial for bacterial elimination, it is also associated with the potential for substantial immunopathology, which underscores the need for tight control of inflammatory responses. The leading human bacterial pathogen Staphylococcus aureus expresses over 100 virulence factors that exert numerous effects upon host cells. In this manner, the pathogen seeks to avoid host recognition or perturb PRR-induced innate immune responses to allow optimal survival in the host. These immune system interactions may result in enhanced bacterial proliferation but also provoke systemic cytokine responses associated with sepsis. This review summarizes recent findings on the various mechanisms applied by S. aureus to modulate or interfere with inflammatory responses through PRRs. Detailed understanding of these complex interactions can provide new insights toward future immune-stimulatory therapeutics against infection or immunomodulatory therapeutics to suppress or correct dysregulated inflammation.
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Affiliation(s)
- Fatemeh Askarian
- Research Group of Host Microbe Interaction, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA 92093, USA
| | - Theresa Wagner
- Research Group of Host Microbe Interaction, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Mona Johannessen
- Research Group of Host Microbe Interaction, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, CA 92093, USA
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Chen K, Fu Q, Liang S, Liu Y, Qu W, Wu Y, Wu X, Wei L, Wang Y, Xiong Y, Wang W, Wu M. Stimulator of Interferon Genes Promotes Host Resistance Against Pseudomonas aeruginosa Keratitis. Front Immunol 2018; 9:1225. [PMID: 29922287 PMCID: PMC5996077 DOI: 10.3389/fimmu.2018.01225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/16/2018] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa (PA) is the leading cause of bacterial keratitis, especially in those who wear contact lens and who are immunocompromised. Once the invading pathogens are recognized by pattern recognition receptors expressed on the innate immune cells, the innate immune response is stimulated to exert host defense function, which is the first line to fight against PA infection. As a converging point of cytosolic DNA sense signaling, stimulator of interferon genes (STING) was reported to participate in host–pathogen interaction. However, the role of STING in regulating PA-induced corneal inflammation and bacterial clearance remains unknown. Our data demonstrated that STING was activated in murine model of PA keratitis and in in vitro-cultured macrophages, indicated by Western blot, immunostaining, and flow cytometry. To explore the role of STING in PA keratitis, we used siRNA to silence STING and 2′,3′-cGAMP to activate STING in vivo and in vitro, and the in vivo data found out that STING promoted host resistance against PA infection. To investigate the reason why STING played a protective role in PA keratitis, the inflammatory cytokine secretion and bacterial load were measured by using real-time PCR and bacterial plate count, respectively. Our data demonstrated that STING suppressed the production of inflammatory cytokines and enhanced bacterial elimination in murine model of PA keratitis and in PA-infected macrophages. To further investigate the mechanism beneath, the phosphorylation of mitogen-activated protein kinase, the nuclear translocation of nuclear factor-κB (NF-κB) and the bactericidal mechanism were measured by western-blot, immunofluorescence, and real-time PCR, respectively. Our data indicated that STING suppressed inflammatory cytokine expressing via restraining NF-κB activity and enhanced inducible NO synthase expression, an oxygen-dependent bactericidal mechanism. In conclusion, this study demonstrated that STING promoted host resistance against PA keratitis and played a protective role in PA-infected corneal disease, via inhibiting corneal inflammation and enhancing bacterial killing.
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Affiliation(s)
- Kang Chen
- Department of Laboratory Medicine, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Qiang Fu
- Department of Laboratory Medicine, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Siping Liang
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering & Technology Research Center for Disease-Model Animals, Sun Yat-sen University, Guangzhou, China
| | - Yiting Liu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering & Technology Research Center for Disease-Model Animals, Sun Yat-sen University, Guangzhou, China
| | - Wenting Qu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering & Technology Research Center for Disease-Model Animals, Sun Yat-sen University, Guangzhou, China
| | - Yongjian Wu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering & Technology Research Center for Disease-Model Animals, Sun Yat-sen University, Guangzhou, China
| | - Xinger Wu
- Department of Laboratory Medicine, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Lei Wei
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yi Wang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yujuan Xiong
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Weijia Wang
- Department of Laboratory Medicine, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Minhao Wu
- Program of Pathobiology and Immunology, Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering & Technology Research Center for Disease-Model Animals, Sun Yat-sen University, Guangzhou, China
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Malaria parasite DNA-harbouring vesicles activate cytosolic immune sensors. Nat Commun 2017; 8:1985. [PMID: 29215015 PMCID: PMC5719353 DOI: 10.1038/s41467-017-02083-1] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 11/06/2017] [Indexed: 12/30/2022] Open
Abstract
STING is an innate immune cytosolic adaptor for DNA sensors that engage malaria parasite (Plasmodium falciparum) or other pathogen DNA. As P. falciparum infects red blood cells and not leukocytes, how parasite DNA reaches such host cytosolic DNA sensors in immune cells is unclear. Here we show that malaria parasites inside red blood cells can engage host cytosolic innate immune cell receptors from a distance by secreting extracellular vesicles (EV) containing parasitic small RNA and genomic DNA. Upon internalization of DNA-harboring EVs by human monocytes, P. falciparum DNA is released within the host cell cytosol, leading to STING-dependent DNA sensing. STING subsequently activates the kinase TBK1, which phosphorylates the transcription factor IRF3, causing IRF3 to translocate to the nucleus and induce STING-dependent gene expression. This DNA-sensing pathway may be an important decoy mechanism to promote P. falciparum virulence and thereby may affect future strategies to treat malaria. STING is an intracellular DNA sensor that can alter response to infection, but in the case of malaria it is unclear how parasite DNA in red blood cells (RBCs) reaches DNA sensors in immune cells. Here the authors show that STING in human monocytes can sense P. falciparum nucleic acids transported from infected RBCs via parasite extracellular vesicles.
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Devaux L, Kaminski PA, Trieu-Cuot P, Firon A. Cyclic di-AMP in host-pathogen interactions. Curr Opin Microbiol 2017; 41:21-28. [PMID: 29169058 DOI: 10.1016/j.mib.2017.11.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/24/2017] [Accepted: 11/04/2017] [Indexed: 01/09/2023]
Abstract
Cyclic di-AMP (c-di-AMP) is a bacterial signaling nucleotide synthesized by several human pathogens. This widespread and specific bacterial product is recognized by infected host cells to trigger an innate immune response. Detection of c-di-AMP in the host cytosol leads primarily to the induction of type I interferon via the STING-cGAS signaling axis, while being also entangled in the activation of the NF-κB pathway. During their long-standing interaction, host and pathogens have co-evolved to control c-di-AMP activation of innate immunity. On the bacterial side, the quantity of c-di-AMP released inside cells allows to manipulate the host response to exacerbate infection by avoiding immune recognition or, at the opposite, by overloading the STING-cGAS pathway.
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Affiliation(s)
- Laura Devaux
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France.
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