51
|
Abstract
The innate immune system recognizes microbial products using germline-encoded receptors that initiate inflammatory responses to infection. The bacterial cell wall component peptidoglycan is a prime example of a conserved pathogen-associated molecular pattern (PAMP) for which the innate immune system has evolved sensing mechanisms. Peptidoglycan is a direct target for innate immune receptors and also regulates the accessibility of other PAMPs to additional innate immune receptors. Subtle structural modifications to peptidoglycan can influence the ability of the innate immune system to detect bacteria and can allow bacteria to evade or alter host defences. This Review focuses on the mechanisms of peptidoglycan recognition that are used by mammalian cells and discusses new insights into the role of peptidoglycan recognition in inflammation, metabolism, immune homeostasis and disease.
Collapse
Affiliation(s)
- Andrea J Wolf
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center
| | - David M Underhill
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center.,Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, California 90048, USA
| |
Collapse
|
52
|
Phagocytic Receptors Activate Syk and Src Signaling during Borrelia burgdorferi Phagocytosis. Infect Immun 2017; 85:IAI.00004-17. [PMID: 28717031 DOI: 10.1128/iai.00004-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/10/2017] [Indexed: 11/20/2022] Open
Abstract
Phagocytosis of the Lyme disease-causing pathogen Borrelia burgdorferi has been shown to be important for generating an inflammatory response to the pathogen. As a result, understanding the mechanisms of phagocytosis has been an area of great interest in the field of Lyme disease. Several cell surface receptors that participate in B. burgdorferi phagocytosis have been reported, including the scavenger receptor MARCO and integrin α3β1. We sought to define the mechanisms by which these receptors mediate phagocytosis and to identify signaling pathways activated downstream of these receptors upon contact with B. burgdorferi We identified both Syk and Src signaling pathways as ones that participate in B. burgdorferi phagocytosis and the resulting cytokine activation. In our studies, we found that both MARCO and integrin β1 play a role in the activation of the Src kinase pathway. However, only integrin β1 participates in the activation of Syk. Interestingly, the integrin activates Syk without the help of the signaling adaptor Dap12 or FcRγ. Thus, we report that multiple pathways participate in B. burgdorferi internalization and that different cell surface receptors act simultaneously in cooperation and independently to mediate phagocytosis.
Collapse
|
53
|
Narasimhaswamy N, Bairy I, Shenoy G, Bairy L. In vitro activity of recombinant lysostaphin in combination with linezolid, vancomycin and oxacillin against methicillin-resistant Staphylococcus aureus. IRANIAN JOURNAL OF MICROBIOLOGY 2017; 9:208-212. [PMID: 29238455 PMCID: PMC5723972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND AND OBJECTIVES The antimicrobial combination with synergistic mechanism is recommended to provide broad-spectrum coverage, and prevent the emergence of resistant mutants. In the present study, the synergistic activity of lysostaphin with linezolid, oxacillin and vancomycin, against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates was determined. MATERIALS AND METHODS Seventy-three MRSA isolates collected from clinical specimens were tested, for in vitro synergistic activity of lysostaphin with linezolid, vancomycin and oxacillin, by checkerboard assay. RESULTS Lysostaphin showed synergistic activity with linezolid and oxacillin, against all MRSA isolates, tested in the present study. Whereas, only 19.1% of the isolates showed synergistic activity with vancomycin and remaining 80.9% of the MRSA isolates showed additive activity. CONCLUSION Lysostaphin causes rapid lysis of S. aureus. Combination therapies that include linezolid and lysostaphin could be used in life-threatening infections, such as endocarditis to increase the early in vivo activity of the antibiotics, and to prevent the emergence of linezolid resistant mutants. Further, in vivo studies are warranted to confirm our results.
Collapse
Affiliation(s)
- Nagalakshmi Narasimhaswamy
- Department of Microbiology, Melaka Manipal Medical College (Manipal Campus) Manipal University, Manipal, Karnataka 576104, India
| | - Indira Bairy
- Department of Microbiology, Melaka Manipal Medical College (Manipal Campus) Manipal University, Manipal, Karnataka 576104, India,Corresponding author: Dr. Indira Bairy, Department of Microbiology, Melaka Manipal Medical College (Manipal Campus), Manipal, Karnataka 576104, India.
| | - Gautham Shenoy
- Department of Pharmaceutical Chemistry, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal, Karnataka 576104, India
| | - Laxminarayana Bairy
- Department of Pharmacology, RAK Medical and Health Sciences University, Ras Al Khaimah, UAE
| |
Collapse
|
54
|
Reciprocal regulation of TLR2-mediated IFN-β production by SHP2 and Gsk3β. Sci Rep 2017; 7:6807. [PMID: 28754897 PMCID: PMC5533723 DOI: 10.1038/s41598-017-07316-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/26/2017] [Indexed: 11/09/2022] Open
Abstract
Toll-like receptor 2 (TLR2) mediates the innate immune response to bacterial lipopeptides and peptidoglycans by stimulating the production of inflammatory cytokines. However, the mechanisms by which TLR2 signaling regulates type I interferon (IFN)-β production are poorly understood. Here, we identified Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) as a negative regulator of TLR2-induced IFN-β production. Pharmacological inhibition or reduced expression of SHP2 potentiated TLR2 agonist-mediated IFN-β transcription and STAT1 activation, whereas overexpression of SHP2 impaired IFN-β transcription and STAT1 activation. SHP2 physically associated with the glycogen synthase kinase 3β (Gsk3β) in an agonist-dependent manner. Gsk3β positively regulates transcription of IFN-β following TLR2 stimulation by inhibiting the phosphorylation of SHP2. SHP2 inhibited the transcriptional activity of IRF-1 and IRF-8 at the IFN-β promoter. Remarkably, IRF-1 and IRF-8 are recruited to the IFN-β promoter in a SHP2 phosphatase activity-dependent manner. These findings provide insight into the mechanisms by which SHP2 and Gsk3β work together to modulate TLR2-mediated IFN-β production in macrophages.
Collapse
|
55
|
Lou J, Li X, Huang W, Liang J, Zheng M, Xu T, Lyu J, Li D, Xu Q, Jin X, Fu G, Wang D, Lu L. SNX10 promotes phagosome maturation in macrophages and protects mice against Listeria monocytogenes infection. Oncotarget 2017; 8:53935-53947. [PMID: 28903313 PMCID: PMC5589552 DOI: 10.18632/oncotarget.19644] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/13/2017] [Indexed: 12/29/2022] Open
Abstract
Listeria monocytogenes (L. monocytogenes), which is a facultative intracellular bacterial pathogen that causes listeriosis, is widely used to study the mammalian immune response to infection. After phagocytosis by professional phagocytes, L. monocytogenes is initially contained within phagosomes, which mature into phagolysosomes, where the bacteria are degraded. Although phagocytosis and subsequent phagosome maturation is essential for the clearance of infectious microbial pathogens, the underlying regulatory mechanisms are still unclear. SNX10 (Sorting nexin 10) has the simplest structure of the SNX family and has been reported to regulate endosomal morphology, which might be crucial for macrophage function, including phagocytosis and digestion of pathogens, inflammatory response, and antigen presentation. Our results showed that SNX10 expression was upregulated following L. monocytogenes infection in macrophages. It was also revealed that SNX10 promoted phagosome maturation by recruiting the Mon1-Ccz1 complex to endosomes and phagosomes. As a result, SNX10 deficiency decreased the bacterial killing ability of macrophages, and SNX10-deficient mice showed increased susceptibility to L. monocytogenes infection in vivo. Thus, this study revealed an essential role of SNX10 in controlling bacterial infection.
Collapse
Affiliation(s)
- Jun Lou
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiawei Li
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Huang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jingjing Liang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Mingzhu Zheng
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ting Xu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Lyu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Dan Li
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Qin Xu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xuexiao Jin
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Guotong Fu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Di Wang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Linrong Lu
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China.,Program in Molecular and Cellular Biology, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
56
|
Srisuwan S, Voravuthikunchai SP. Rhodomyrtus tomentosa Leaf Extract Inhibits Methicillin-Resistant Staphylococcus aureus Adhesion, Invasion, and Intracellular Survival in Human HaCaT Keratinocytes. Microb Drug Resist 2017; 23:1002-1012. [PMID: 28475464 DOI: 10.1089/mdr.2016.0284] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) has an ability to invade nonprofessional phagocytic cells, resulting in persistent infections and most likely host cell death. Series of our studies have claimed pronounced antibacterial efficacy of Rhodomyrtus tomentosa leaf extract. This study was to further investigate potency of the extract in intracellular killing of human HaCaT keratinocytes. Pretreatment of MRSA with the extract resulted in a remarkable reduction in the bacterial adhesion to HaCaT keratinocytes, compared with untreated control (p < 0.001). In addition, at least 60% inhibition of the bacterial invasion into HaCaT cells was observed. Intracellular killing assay demonstrated that the extract exhibited strong antibacterial activity against intracellular MRSA at nontoxic concentrations (128 mg/L), which may have resulted from the increase in bactericidal activity under phagolysosomal pH. Transmission electron microscopy displayed the effects of the extract on alterations in the bacterial cell morphology with cell lysis. Fluorescence microscopy revealed that the extract decreased MRSA-induced apoptosis in HaCaT cells. In addition, cytotoxicity of HaCaT cells caused by MRSA supernatant was reduced at least 50% by the extract. The potential activities of R. tomentosa extract may be useful in an alternative treatment of MRSA infections in slight acidic compartments, particularly skin infections.
Collapse
Affiliation(s)
- Sutthirat Srisuwan
- Excellence Research Laboratory on Natural Products and Department of Microbiology, Faculty of Science and Natural Products Research Center of Excellence, Prince of Songkla University , Songkhla, Thailand
| | - Supayang Piyawan Voravuthikunchai
- Excellence Research Laboratory on Natural Products and Department of Microbiology, Faculty of Science and Natural Products Research Center of Excellence, Prince of Songkla University , Songkhla, Thailand
| |
Collapse
|
57
|
MyD88 in Mycobacterium tuberculosis infection. Med Microbiol Immunol 2017; 206:187-193. [PMID: 28220253 DOI: 10.1007/s00430-017-0495-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/27/2017] [Indexed: 01/15/2023]
Abstract
MyD88 adaptor protein mediates numerous biologically important signal transduction pathways in innate immunity. MyD88 signaling fosters bacterial containment and is necessary to raise an adequate innate and acquired immune response to Mycobacterium tuberculosis (Mtb). The phagosome is a crucial cellular location not only for Mtb replication, but it is also where components of the Myddosome and inflammasome are recruited. Besides its function as a TLR-adaptor protein, MyD88 may help stabilizing cytosolic receptors that are recruited to the phagosome. MyD88 plays a critical role not only in the generation of an inflammatory response, but also in inducing regulatory signals to prevent excessive inflammation and cellular damage in the lung.
Collapse
|
58
|
Shifts in the fluorescence lifetime of EGFP during bacterial phagocytosis measured by phase-sensitive flow cytometry. Sci Rep 2017; 7:40341. [PMID: 28091553 PMCID: PMC5238435 DOI: 10.1038/srep40341] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 12/05/2016] [Indexed: 12/21/2022] Open
Abstract
Phase-sensitive flow cytometry (PSFC) is a technique in which fluorescence excited state decay times are measured as fluorescently labeled cells rapidly transit a finely focused, frequency-modulated laser beam. With PSFC the fluorescence lifetime is taken as a cytometric parameter to differentiate intracellular events that are challenging to distinguish with standard flow cytometry. For example PSFC can report changes in protein conformation, expression, interactions, and movement, as well as differences in intracellular microenvironments. This contribution focuses on the latter case by taking PSFC measurements of macrophage cells when inoculated with enhanced green fluorescent protein (EGFP)-expressing E. coli. During progressive internalization of EGFP-E. coli, fluorescence lifetimes were acquired and compared to control groups. It was hypothesized that fluorescence lifetimes would correlate well with phagocytosis because phagosomes become acidified and the average fluorescence lifetime of EGFP is known to be affected by pH. We confirmed that average EGFP lifetimes consistently decreased (3 to 2 ns) with inoculation time. The broad significance of this work is the demonstration of how high-throughput fluorescence lifetime measurements correlate well to changes that are not easily tracked by intensity-only cytometry, which is affected by heterogeneous protein expression, cell-to-cell differences in phagosome formation, and number of bacterium engulfed.
Collapse
|
59
|
Muñoz-Rugeles L, Galano A, Alvarez-Idaboy JR. The role of acid–base equilibria in formal hydrogen transfer reactions: tryptophan radical repair by uric acid as a paradigmatic case. Phys Chem Chem Phys 2017; 19:15296-15309. [DOI: 10.1039/c7cp01557g] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The sequential proton gain electron transfer and proton electron sequential transfer mechanisms play the most important roles in tryptophan repair by uric acid.
Collapse
Affiliation(s)
- Leonardo Muñoz-Rugeles
- Facultad de Química
- Departamento de Física y Química Teórica
- Universidad Nacional Autónoma de México
- México
- Mexico
| | - Annia Galano
- Departamento de Química
- Universidad Autónoma Metropolitana-Iztapalapa
- México
- Mexico
| | - Juan Raúl Alvarez-Idaboy
- Facultad de Química
- Departamento de Física y Química Teórica
- Universidad Nacional Autónoma de México
- México
- Mexico
| |
Collapse
|
60
|
Hong SJ, Kim SK, Ko EB, Yun CH, Han SH. Wall teichoic acid is an essential component of Staphylococcus aureus for the induction of human dendritic cell maturation. Mol Immunol 2016; 81:135-142. [PMID: 27978487 DOI: 10.1016/j.molimm.2016.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/08/2016] [Accepted: 12/05/2016] [Indexed: 12/30/2022]
Abstract
Staphylococcus aureus is a Gram-positive pathogen that can cause chronic skin inflammation, pneumonia, and septic shock. The immunomodulatory functions of wall teichoic acid (WTA), a glycopolymer abundantly expressed on the Gram-positive bacterial cell wall, are poorly understood. Here, we investigated the role of WTA in the phenotypic and functional activation of human monocyte-derived dendritic cells (DCs) treated with ethanol-killed S. aureus. WTA-deficient S. aureus mutant (ΔtagO) exhibited attenuated binding and internalization to DCs compared to the wild-type. ΔtagO induced lower expression of maturation markers on and cytokines in DCs than the wild-type S. aureus. Furthermore, autologous human peripheral blood mononuclear cells cocultured with ΔtagO-treated DCs exhibited a marked reduction in T cell proliferative activity, the expression of activation markers, and the production of cytokines compared to the wild-type S. aureus-stimulated DCs. Collectively, these results suggest that WTA is an important cell wall component of S. aureus for the induction of DC maturation and activation.
Collapse
Affiliation(s)
- Sung Jun Hong
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun Kyung Kim
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eun Byeol Ko
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institute of Green Bio Science Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea.
| |
Collapse
|
61
|
Wolf AJ, Liu GY, Underhill DM. Inflammatory properties of antibiotic-treated bacteria. J Leukoc Biol 2016; 101:127-134. [PMID: 27576461 DOI: 10.1189/jlb.4mr0316-153rr] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 08/02/2016] [Accepted: 08/05/2016] [Indexed: 12/12/2022] Open
Abstract
Antibiotics have proven to be enormously effective tools in combating infectious diseases. A common roadblock to the effective use of antibiotics is the development of antibiotic resistance. We have recently observed that the very mechanism by which methicillin-resistant Staphylococcus aureus (MRSA) becomes antibiotic resistant causes the organism to be more inflammatory to innate immune cells. In this review, we offer some thoughts on the ways in which antibiotics have been observed to influence immune responses to bacteria.
Collapse
Affiliation(s)
- Andrea J Wolf
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA; and
| | - George Y Liu
- Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA; and.,Division of Pediatric Infectious Diseases, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - David M Underhill
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA; .,Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA; and
| |
Collapse
|
62
|
Wolf AJ, Reyes CN, Liang W, Becker C, Shimada K, Wheeler ML, Cho HC, Popescu NI, Coggeshall KM, Arditi M, Underhill DM. Hexokinase Is an Innate Immune Receptor for the Detection of Bacterial Peptidoglycan. Cell 2016; 166:624-636. [PMID: 27374331 PMCID: PMC5534359 DOI: 10.1016/j.cell.2016.05.076] [Citation(s) in RCA: 390] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 03/11/2016] [Accepted: 05/25/2016] [Indexed: 12/31/2022]
Abstract
Degradation of Gram-positive bacterial cell wall peptidoglycan in macrophage and dendritic cell phagosomes leads to activation of the NLRP3 inflammasome, a cytosolic complex that regulates processing and secretion of interleukin (IL)-1β and IL-18. While many inflammatory responses to peptidoglycan are mediated by detection of its muramyl dipeptide component in the cytosol by NOD2, we report here that NLRP3 inflammasome activation is caused by release of N-acetylglucosamine that is detected in the cytosol by the glycolytic enzyme hexokinase. Inhibition of hexokinase by N-acetylglucosamine causes its dissociation from mitochondria outer membranes, and we found that this is sufficient to activate the NLRP3 inflammasome. In addition, we observed that glycolytic inhibitors and metabolic conditions affecting hexokinase function and localization induce inflammasome activation. While previous studies have demonstrated that signaling by pattern recognition receptors can regulate metabolic processes, this study shows that a metabolic enzyme can act as a pattern recognition receptor. PAPERCLIP.
Collapse
Affiliation(s)
- Andrea J Wolf
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Christopher N Reyes
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Wenbin Liang
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Courtney Becker
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Kenichi Shimada
- Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Pediatric Infectious Diseases, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Matthew L Wheeler
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Hee Cheol Cho
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Narcis I Popescu
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - K Mark Coggeshall
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Moshe Arditi
- Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Pediatric Infectious Diseases, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - David M Underhill
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
| |
Collapse
|
63
|
Rizzetto L, Ifrim DC, Moretti S, Tocci N, Cheng SC, Quintin J, Renga G, Oikonomou V, De Filippo C, Weil T, Blok BA, Lenucci MS, Santos MAS, Romani L, Netea MG, Cavalieri D. Fungal Chitin Induces Trained Immunity in Human Monocytes during Cross-talk of the Host with Saccharomyces cerevisiae. J Biol Chem 2016; 291:7961-72. [PMID: 26887946 DOI: 10.1074/jbc.m115.699645] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Indexed: 11/06/2022] Open
Abstract
The immune system is essential to maintain the mutualistic homeostatic interaction between the host and its micro- and mycobiota. Living as a commensal,Saccharomyces cerevisiaecould potentially shape the immune response in a significant way. We observed thatS. cerevisiaecells induce trained immunity in monocytes in a strain-dependent manner through enhanced TNFα and IL-6 production upon secondary stimulation with TLR ligands, as well as bacterial and fungal commensals. Differential chitin content accounts for the differences in training properties observed among strains, driving induction of trained immunity by increasing cytokine production and direct antimicrobial activity bothin vitroandin vivo These chitin-induced protective properties are intimately associated with its internalization, identifying a critical role of phagosome acidification to facilitate microbial digestion. This study reveals how commensal and passenger microorganisms could be important in promoting health and preventing mucosal diseases by modulating host defense toward pathogens and thus influencing the host microbiota-immune system interactions.
Collapse
Affiliation(s)
- Lisa Rizzetto
- From the Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige TN, Italy
| | - Daniela C Ifrim
- the Department of Internal Medicine, Division of Experimental Internal Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Silvia Moretti
- the Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, 06123 Perugia PG, Italy
| | - Noemi Tocci
- From the Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige TN, Italy
| | - Shih-Chin Cheng
- the Department of Internal Medicine, Division of Experimental Internal Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Jessica Quintin
- the Department of Internal Medicine, Division of Experimental Internal Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Giorgia Renga
- the Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, 06123 Perugia PG, Italy
| | - Vasilis Oikonomou
- the Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, 06123 Perugia PG, Italy
| | - Carlotta De Filippo
- From the Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige TN, Italy, the Institute of Biometeorology, National Research Council, 50145 Florence, Italy
| | - Tobias Weil
- From the Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige TN, Italy
| | - Bastiaan A Blok
- the Department of Internal Medicine, Division of Experimental Internal Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Marcello S Lenucci
- the Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, 73100 Lecce LE, Italy
| | - Manuel A S Santos
- the Department of Biology and CESAM (Centro de Estudos do Ambiente e do Mar), University of Aveiro, 3810-193 Aveiro, Portugal, and
| | - Luigina Romani
- the Department of Experimental Medicine, University of Perugia, Polo Unico Sant'Andrea delle Fratte, 06123 Perugia PG, Italy
| | - Mihai G Netea
- the Department of Internal Medicine, Division of Experimental Internal Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Duccio Cavalieri
- From the Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all'Adige TN, Italy, the Institute of Biometeorology, National Research Council, 50145 Florence, Italy, the Department of Biology, University of Florence, 50019 Sesto Fiorentino FI, Italy
| |
Collapse
|
64
|
Lund LD, Ingmer H, Frøkiær H. D-Alanylation of Teichoic Acids and Loss of Poly-N-Acetyl Glucosamine in Staphylococcus aureus during Exponential Growth Phase Enhance IL-12 Production in Murine Dendritic Cells. PLoS One 2016; 11:e0149092. [PMID: 26872029 PMCID: PMC4752283 DOI: 10.1371/journal.pone.0149092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 01/27/2016] [Indexed: 02/01/2023] Open
Abstract
Staphylococcus aureus is a major human pathogen that has evolved very efficient immune evading strategies leading to persistent colonization. During different stages of growth, S. aureus express various surface molecules, which may affect the immune stimulating properties, but very little is known about their role in immune stimulation and evasion. Depending on the growth phase, S. aureus may affect antigen presenting cells differently. Here, the impact of growth phases and the surface molecules lipoteichoic acid, peptidoglycan and poly-N-acetyl glucosamine on the induction of IL-12 imperative for an efficient clearance of S. aureus was studied in dendritic cells (DCs). Exponential phase (EP) S. aureus was superior to stationary phase (SP) bacteria in induction of IL-12, which required actin-mediated endocytosis and endosomal acidification. Moreover, addition of staphylococcal cell wall derived peptidoglycan to EP S. aureus stimulated cells increased bacterial uptake but abrogated IL-12 induction, while addition of lipoteichoic acid increased IL-12 production but had no effect on the bacterial uptake. Depletion of the capability to produce poly-N-acetyl glucosamine increased the IL-12 inducing activity of EP bacteria. Furthermore, the mutant dltA unable to produce D-alanylated teichoic acids failed to induce IL-12 but like peptidoglycan and the toll-like receptor (TLR) ligands LPS and Pam3CSK4 the mutant stimulated increased macropinocytosis. In conclusion, the IL-12 response by DCs against S. aureus is highly growth phase dependent, relies on cell wall D-alanylation, endocytosis and subsequent endosomal degradation, and is abrogated by receptor induced macropinocytosis.
Collapse
Affiliation(s)
- Lisbeth Drozd Lund
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
| | - Hanne Frøkiær
- Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark
- * E-mail:
| |
Collapse
|
65
|
Billings EA, Lee CS, Owen KA, D'Souza RS, Ravichandran KS, Casanova JE. The adhesion GPCR BAI1 mediates macrophage ROS production and microbicidal activity against Gram-negative bacteria. Sci Signal 2016; 9:ra14. [PMID: 26838550 PMCID: PMC4894535 DOI: 10.1126/scisignal.aac6250] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The detection of microbes and initiation of an innate immune response occur through pattern recognition receptors (PRRs), which are critical for the production of inflammatory cytokines and activation of the cellular microbicidal machinery. In particular, the production of reactive oxygen species (ROS) by the NADPH oxidase complex is a critical component of the macrophage bactericidal machinery. We previously characterized brain-specific angiogenesis inhibitor 1 (BAI1), a member of the adhesion family of G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs), as a PRR that mediates the selective phagocytic uptake of Gram-negative bacteria by macrophages. We showed that BAI1 promoted phagosomal ROS production through activation of the Rho family guanosine triphosphatase (GTPase) Rac1, thereby stimulating NADPH oxidase activity. Primary BAI1-deficient macrophages exhibited attenuated Rac GTPase activity and reduced ROS production in response to several Gram-negative bacteria, resulting in impaired microbicidal activity. Furthermore, in a peritoneal infection model, BAI1-deficient mice exhibited increased susceptibility to death by bacterial challenge because of impaired bacterial clearance. Together, these findings suggest that BAI1 mediates the clearance of Gram-negative bacteria by stimulating both phagocytosis and NADPH oxidase activation, thereby coupling bacterial detection to the cellular microbicidal machinery.
Collapse
Affiliation(s)
- Emily A Billings
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Chang Sup Lee
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Katherine A Owen
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ryan S D'Souza
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - James E Casanova
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA. Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA.
| |
Collapse
|
66
|
Abstract
Phagocytosis is a fundamental process through which innate immune cells engulf bacteria, apoptotic cells or other foreign particles in order to kill or neutralize the ingested material, or to present it as antigens and initiate adaptive immune responses. The pH of phagosomes is a critical parameter regulating fission or fusion with endomembranes and activation of proteolytic enzymes, events that allow the phagocytic vacuole to mature into a degradative organelle. In addition, translocation of H(+) is required for the production of high levels of reactive oxygen species (ROS), which are essential for efficient killing and signaling to other host tissues. Many intracellular pathogens subvert phagocytic killing by limiting phagosomal acidification, highlighting the importance of pH in phagosome biology. Here we describe a ratiometric method for measuring phagosomal pH in neutrophils using fluorescein isothiocyanate (FITC)-labeled zymosan as phagocytic targets, and live-cell imaging. The assay is based on the fluorescence properties of FITC, which is quenched by acidic pH when excited at 490 nm but not when excited at 440 nm, allowing quantification of a pH-dependent ratio, rather than absolute fluorescence, of a single dye. A detailed protocol for performing in situ dye calibration and conversion of ratio to real pH values is also provided. Single-dye ratiometric methods are generally considered superior to single wavelength or dual-dye pseudo-ratiometric protocols, as they are less sensitive to perturbations such as bleaching, focus changes, laser variations, and uneven labeling, which distort the measured signal. This method can be easily modified to measure pH in other phagocytic cell types, and zymosan can be replaced by any other amine-containing particle, from inert beads to living microorganisms. Finally, this method can be adapted to make use of other fluorescent probes sensitive to different pH ranges or other phagosomal activities, making it a generalized protocol for the functional imaging of phagosomes.
Collapse
Affiliation(s)
- Paula Nunes
- Department of Cellular Physiology and Metabolism, University of Geneva;
| | - Daniele Guido
- Department of Cellular Physiology and Metabolism, University of Geneva
| | - Nicolas Demaurex
- Department of Cellular Physiology and Metabolism, University of Geneva
| |
Collapse
|
67
|
Hambsch ZJ, Kerfeld MJ, Kirkpatrick DR, McEntire DM, Reisbig MD, Youngblood CF, Agrawal DK. Arterial Catheterization and Infection: Toll-like Receptors in Defense against Microorganisms and Therapeutic Implications. Clin Transl Sci 2015; 8:857-70. [PMID: 26271949 PMCID: PMC4703511 DOI: 10.1111/cts.12320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Radial artery catheterization has become a preferred route over femoral artery catheterization, in order to monitor the blood pressure of hemodynamically unstable patients or for repeated sampling of arterial blood gases. While the incidence of catheter-related infection is lower in the radial artery than the femoral artery, infection remains a major issue that requires attention. In this review of the literature, we discuss infectious complications of radial artery catheterization, with a focus on various risk factors and establishing the most common causative agents. We also critically review the role of the innate immune system involving Toll-like receptors (TLRs) in host-defense, with the goal of establishing a common pathway used by the innate immune system via TLRs to combat the pathogens that most commonly cause infection in radial artery catheterization. If this pathway can be therapeutically manipulated to preemptively attack pathogenic agents, immunomodulation may be an option in reducing the incidence of infection in this procedure.
Collapse
Affiliation(s)
- Zakary J. Hambsch
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Mitchell J. Kerfeld
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Daniel R. Kirkpatrick
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Dan M. McEntire
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Mark D. Reisbig
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Charles F. Youngblood
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| | - Devendra K. Agrawal
- Center for Clinical & Translational Science and Department of AnesthesiologyCreighton University School of MedicineOmahaNebraskaUSA
| |
Collapse
|
68
|
Flannagan RS, Heit B, Heinrichs DE. Antimicrobial Mechanisms of Macrophages and the Immune Evasion Strategies of Staphylococcus aureus. Pathogens 2015; 4:826-68. [PMID: 26633519 PMCID: PMC4693167 DOI: 10.3390/pathogens4040826] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/17/2015] [Accepted: 11/24/2015] [Indexed: 12/21/2022] Open
Abstract
Habitually professional phagocytes, including macrophages, eradicate microbial invaders from the human body without overt signs of infection. Despite this, there exist select bacteria that are professional pathogens, causing significant morbidity and mortality across the globe and Staphylococcus aureus is no exception. S. aureus is a highly successful pathogen that can infect virtually every tissue that comprises the human body causing a broad spectrum of diseases. The profound pathogenic capacity of S. aureus can be attributed, in part, to its ability to elaborate a profusion of bacterial effectors that circumvent host immunity. Macrophages are important professional phagocytes that contribute to both the innate and adaptive immune response, however from in vitro and in vivo studies, it is evident that they fail to eradicate S. aureus. This review provides an overview of the antimicrobial mechanisms employed by macrophages to combat bacteria and describes the immune evasion strategies and some representative effectors that enable S. aureus to evade macrophage-mediated killing.
Collapse
Affiliation(s)
- Ronald S Flannagan
- Department of Microbiology and Immunology, the University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Bryan Heit
- Department of Microbiology and Immunology, the University of Western Ontario, London, ON N6A 5C1, Canada.
- Centre for Human Immunology, the University of Western Ontario, London, ON N6A 5C1, Canada.
| | - David E Heinrichs
- Department of Microbiology and Immunology, the University of Western Ontario, London, ON N6A 5C1, Canada.
- Centre for Human Immunology, the University of Western Ontario, London, ON N6A 5C1, Canada.
| |
Collapse
|
69
|
Tosh KW, Mittereder L, Bonne-Annee S, Hieny S, Nutman TB, Singer SM, Sher A, Jankovic D. The IL-12 Response of Primary Human Dendritic Cells and Monocytes to Toxoplasma gondii Is Stimulated by Phagocytosis of Live Parasites Rather Than Host Cell Invasion. THE JOURNAL OF IMMUNOLOGY 2015; 196:345-56. [PMID: 26597011 DOI: 10.4049/jimmunol.1501558] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/21/2015] [Indexed: 12/11/2022]
Abstract
As a major natural host for Toxoplasma gondii, the mouse is widely used for the study of the immune response to this medically important protozoan parasite. However, murine innate recognition of toxoplasma depends on the interaction of parasite profilin with TLR11 and TLR12, two receptors that are functionally absent in humans. This raises the question of how human cells detect and respond to T. gondii. In this study, we show that primary monocytes and dendritic cells from peripheral blood of healthy donors produce IL-12 and other proinflammatory cytokines when exposed to toxoplasma tachyzoites. Cell fractionation studies determined that IL-12 and TNF-α secretion is limited to CD16(+) monocytes and the CD1c(+) subset of dendritic cells. In direct contrast to their murine counterparts, human myeloid cells fail to respond to soluble tachyzoite extracts and instead require contact with live parasites. Importantly, we found that tachyzoite phagocytosis, but not host cell invasion, is required for cytokine induction. Together these findings identify CD16(+) monocytes and CD1c(+) dendritic cells as the major myeloid subsets in human blood-producing innate cytokines in response to T. gondii and demonstrate an unappreciated requirement for phagocytosis of live parasites in that process. This form of pathogen sensing is distinct from that used by mice, possibly reflecting a direct involvement of rodents and not humans in the parasite life cycle.
Collapse
Affiliation(s)
- Kevin W Tosh
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; Department of Biology, Georgetown University, Washington, DC 20057; and
| | - Lara Mittereder
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sandra Bonne-Annee
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Sara Hieny
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Thomas B Nutman
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Steven M Singer
- Department of Biology, Georgetown University, Washington, DC 20057; and
| | - Alan Sher
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Dragana Jankovic
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
| |
Collapse
|
70
|
Immunomodulation and Disease Tolerance to Staphylococcus aureus. Pathogens 2015; 4:793-815. [PMID: 26580658 PMCID: PMC4693165 DOI: 10.3390/pathogens4040793] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 12/12/2022] Open
Abstract
The Gram-positive bacterium Staphylococcus aureus is one of the most frequent pathogens that causes severe morbidity and mortality throughout the world. S. aureus can infect skin and soft tissues or become invasive leading to diseases such as pneumonia, endocarditis, sepsis or toxic shock syndrome. In contrast, S. aureus is also a common commensal microbe and is often part of the human nasal microbiome without causing any apparent disease. In this review, we explore the immunomodulation and disease tolerance mechanisms that promote commensalism to S. aureus.
Collapse
|
71
|
TRPC6 channel translocation into phagosomal membrane augments phagosomal function. Proc Natl Acad Sci U S A 2015; 112:E6486-95. [PMID: 26604306 DOI: 10.1073/pnas.1518966112] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects in the innate immune system in the lung with attendant bacterial infections contribute to lung tissue damage, respiratory insufficiency, and ultimately death in the pathogenesis of cystic fibrosis (CF). Professional phagocytes, including alveolar macrophages (AMs), have specialized pathways that ensure efficient killing of pathogens in phagosomes. Phagosomal acidification facilitates the optimal functioning of degradative enzymes, ultimately contributing to bacterial killing. Generation of low organellar pH is primarily driven by the V-ATPases, proton pumps that use cytoplasmic ATP to load H(+) into the organelle. Critical to phagosomal acidification are various channels derived from the plasma membrane, including the anion channel cystic fibrosis transmembrane conductance regulator, which shunt the transmembrane potential generated by movement of protons. Here we show that the transient receptor potential canonical-6 (TRPC6) calcium-permeable channel in the AM also functions to shunt the transmembrane potential generated by proton pumping and is capable of restoring microbicidal function to compromised AMs in CF and enhancement of function in non-CF cells. TRPC6 channel activity is enhanced via translocation to the cell surface (and then ultimately to the phagosome during phagocytosis) in response to G-protein signaling activated by the small molecule (R)-roscovitine and its derivatives. These data show that enhancing vesicular insertion of the TRPC6 channel to the plasma membrane may represent a general mechanism for restoring phagosome activity in conditions, where it is lost or impaired.
Collapse
|
72
|
Zhu F, Zhou Y, Jiang C, Zhang X. Role of JAK-STAT signaling in maturation of phagosomes containing Staphylococcus aureus. Sci Rep 2015; 5:14854. [PMID: 26442670 PMCID: PMC4595848 DOI: 10.1038/srep14854] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 08/17/2015] [Indexed: 01/19/2023] Open
Abstract
Phagocytosis is a required mechanism for the defense against pathogens. Staphylococcus aureus, an important bacterial pathogen, can promptly escape from phagosomes and proliferate within the cytoplasm of host. However, the mechanism of phagocytosis against S. aureus has not been intensively investigated. In this study, the S. aureus was engulfed by macrophages (RAW264.7 cells) but not digested by the cells, suggesting that the phagosomes did not maturate in macrophages. Further investigation revealed that peptidoglycan (PG) induced the phagosome maturation of macrophages, resulting in the eradication of S. aureus. Genome-wide analysis and quantitative real-time PCR indicated that the JAK-STAT pathway was activated by PG during the phagosome maturation of macrophages against S. aureus. This finding presented that the PG-activated JAK-STAT pathway was required for phagosome maturation. Therefore, our study contributed evidence that revealed a novel aspect of PG-triggered JAK-STAT pathway in the phagosome maturation of macrophages.
Collapse
Affiliation(s)
- Fei Zhu
- Collaborative Innovation Center of Deep Sea Biology, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, China.,College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Yadong Zhou
- Collaborative Innovation Center of Deep Sea Biology, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chunxia Jiang
- Collaborative Innovation Center of Deep Sea Biology, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xiaobo Zhang
- Collaborative Innovation Center of Deep Sea Biology, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| |
Collapse
|
73
|
Petnicki-Ocwieja T, Kern A, Killpack TL, Bunnell SC, Hu LT. Adaptor Protein-3-Mediated Trafficking of TLR2 Ligands Controls Specificity of Inflammatory Responses but Not Adaptor Complex Assembly. THE JOURNAL OF IMMUNOLOGY 2015; 195:4331-40. [PMID: 26423153 DOI: 10.4049/jimmunol.1501268] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/29/2015] [Indexed: 11/19/2022]
Abstract
Innate immune engagement results in the activation of host defenses that produce microbe-specific inflammatory responses. A long-standing interest in the field of innate immunity is to understand how varied host responses are generated through the signaling of just a limited number of receptors. Recently, intracellular trafficking and compartmental partitioning have been identified as mechanisms that provide signaling specificity for receptors by regulating signaling platform assembly. We show that cytokine activation as a result of TLR2 stimulation occurs at different intracellular locations and is mediated by the phagosomal trafficking molecule adaptor protein-3 (AP-3). AP-3 is required for trafficking TLR2 purified ligands or the Lyme disease causing bacterium, Borrelia burgdorferi, to LAMP-1 lysosomal compartments. The presence of AP-3 is necessary for the activation of cytokines such as IL-6 but not TNF-α or type I IFNs, suggesting induction of these cytokines occurs from a different compartment. Lack of AP-3 does not interfere with the recruitment of TLR signaling adaptors TRAM and MyD88 to the phagosome, indicating that the TLR-MyD88 signaling complex is assembled at a prelysosomal stage and that IL-6 activation depends on proper localization of signaling molecules downstream of MyD88. Finally, infection of AP-3-deficient mice with B. burgdorferi resulted in altered joint inflammation during murine Lyme arthritis. Our studies further elucidate the effects of phagosomal trafficking on tailoring immune responses in vitro and in vivo.
Collapse
Affiliation(s)
- Tanja Petnicki-Ocwieja
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111; and
| | - Aurelie Kern
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111; and
| | - Tess L Killpack
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111; and
| | - Stephen C Bunnell
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, MA 02111
| | - Linden T Hu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111; and
| |
Collapse
|
74
|
Bergstrøm B, Aune MH, Awuh JA, Kojen JF, Blix KJ, Ryan L, Flo TH, Mollnes TE, Espevik T, Stenvik J. TLR8 Senses Staphylococcus aureus RNA in Human Primary Monocytes and Macrophages and Induces IFN-β Production via a TAK1–IKKβ–IRF5 Signaling Pathway. THE JOURNAL OF IMMUNOLOGY 2015; 195:1100-11. [DOI: 10.4049/jimmunol.1403176] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/20/2015] [Indexed: 01/08/2023]
|
75
|
Uncoupling of pro- and anti-inflammatory properties of Staphylococcus aureus. Infect Immun 2015; 83:1587-97. [PMID: 25644014 DOI: 10.1128/iai.02832-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus is a Gram-positive bacterium that is carried by a quarter of the healthy human population and that can cause severe infections. This pathobiosis has been linked to a balance between Toll-like receptor 2 (TLR2)-dependent pro- and anti-inflammatory responses. The relationship between these two types of responses is unknown. Analysis of 16 nasal isolates of S. aureus showed heterogeneity in their capacity to induce pro- and anti-inflammatory responses, suggesting that these two responses are independent of each other. Uncoupling of these responses was corroborated by selective signaling through phosphoinositol 3-kinase (PI3K)-Akt-mTOR and extracellular signal-regulated kinase (ERK) for the anti-inflammatory response and through p38 for the proinflammatory response. Uncoupling was also observed at the level of phagocytosis and phagosomal processing of S. aureus, which were required solely for the proinflammatory response. Importantly, the anti-inflammatory properties of an S. aureus isolate correlated with its ability to modulate T cell immunity. Our results suggest the presence of anti-inflammatory TLR2 ligands in the staphylococcal cell wall, whose identification may provide templates for novel immunomodulatory drugs.
Collapse
|
76
|
|
77
|
Alvarado R, O'Brien B, Tanaka A, Dalton JP, Donnelly S. A parasitic helminth-derived peptide that targets the macrophage lysosome is a novel therapeutic option for autoimmune disease. Immunobiology 2014; 220:262-9. [PMID: 25466586 DOI: 10.1016/j.imbio.2014.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 12/24/2022]
Abstract
Parasitic worms (helminths) reside in their mammalian hosts for many years. This is attributable, in part, to their ability to skew the host's immune system away from pro-inflammatory responses and towards anti-inflammatory or regulatory responses. This immune modulatory ability ensures helminth longevity within the host, while simultaneously minimises tissue destruction for the host. The molecules that the parasite releases clearly exert potent immune-modulatory actions, which could be exploited clinically, for example in the prophylactic and therapeutic treatment of pro-inflammatory and autoimmune diseases. We have identified a novel family of immune-modulatory proteins, termed helminth defence molecules (HDMs), which are secreted by several medically important helminth parasites. These HDMs share biochemical and structural characteristics with mammalian cathelicidin-like host defence peptides (HDPs), which are significant components of the innate immune system. Like their mammalian counterparts, parasite HDMs block the activation of macrophages via toll like receptor (TLR) 4 signalling, however HDMs are significantly less cytotoxic than HDPs. HDMs can traverse the cell membrane of macrophages and enter the endolysosomal system where they reduce the acidification of lysosomal compartments by inhibiting vacuolar (v)-ATPase activity. In doing this, HDMs can modulate critical cellular functions, such as cytokine secretion and antigen processing/presentation. Here, we review the role of macrophages, specifically their lysosomal mediated activities, in the initiation and perpetuation of pro-inflammatory immune responses. We also discuss the potential of helminth defence molecules (HDMs) as therapeutics to counteract the pro-inflammatory responses underlying autoimmune disease. Given the current lack of effective, non-cytotoxic treatment options to limit the progression of autoimmune pathologies, HDMs open novel treatment avenues.
Collapse
Affiliation(s)
- Raquel Alvarado
- School of Medical and Molecular Biosciences, University of Technology, Sydney, Sydney, NSW, Australia
| | - Bronwyn O'Brien
- School of Medical and Molecular Biosciences, University of Technology, Sydney, Sydney, NSW, Australia
| | - Akane Tanaka
- School of Medical and Molecular Biosciences, University of Technology, Sydney, Sydney, NSW, Australia
| | - John P Dalton
- School of Biological Sciences, Medical Biology Centre, Queen's University, Belfast, Belfast, Northern Ireland, UK
| | - Sheila Donnelly
- School of Medical and Molecular Biosciences, University of Technology, Sydney, Sydney, NSW, Australia; The i3 Institute, University of Technology, Sydney, Sydney, NSW, Australia.
| |
Collapse
|
78
|
Cole J, Aberdein J, Jubrail J, Dockrell DH. The role of macrophages in the innate immune response to Streptococcus pneumoniae and Staphylococcus aureus: mechanisms and contrasts. Adv Microb Physiol 2014; 65:125-202. [PMID: 25476766 DOI: 10.1016/bs.ampbs.2014.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Macrophages are critical mediators of innate immune responses against bacteria. The Gram-positive bacteria Streptococcus pneumoniae and Staphylococcus aureus express a range of virulence factors, which challenge macrophages' immune competence. We review how macrophages respond to this challenge. Macrophages employ a range of strategies to phagocytose and kill each pathogen. When the macrophages capacity to clear bacteria is overwhelmed macrophages play important roles in orchestrating the inflammatory response through pattern recognition receptor-mediated responses. Macrophages also ensure the inflammatory response is tightly constrained, to avoid tissue damage, and play an important role in downregulating the inflammatory response once initial bacterial replication is controlled.
Collapse
Affiliation(s)
- Joby Cole
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jody Aberdein
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - Jamil Jubrail
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom
| | - David H Dockrell
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, United Kingdom.
| |
Collapse
|
79
|
Pneumolysin activates macrophage lysosomal membrane permeabilization and executes apoptosis by distinct mechanisms without membrane pore formation. mBio 2014; 5:e01710-14. [PMID: 25293758 PMCID: PMC4196231 DOI: 10.1128/mbio.01710-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intracellular killing of Streptococcus pneumoniae is complemented by induction of macrophage apoptosis. Here, we show that the toxin pneumolysin (PLY) contributes both to lysosomal/phagolysosomal membrane permeabilization (LMP), an upstream event programing susceptibility to apoptosis, and to apoptosis execution via a mitochondrial pathway, through distinct mechanisms. PLY is necessary but not sufficient for the maximal induction of LMP and apoptosis. PLY's ability to induce both LMP and apoptosis is independent of its ability to form cytolytic pores and requires only the first three domains of PLY. LMP involves TLR (Toll-like receptor) but not NLRP3/ASC (nucleotide-binding oligomerization domain [Nod]-like receptor family, pyrin domain-containing protein 3/apoptosis-associated speck-like protein containing a caspase recruitment domain) signaling and is part of a PLY-dependent but phagocytosis-independent host response that includes the production of cytokines, including interleukin-1 beta (IL-1β). LMP involves progressive and selective permeability to 40-kDa but not to 250-kDa fluorescein isothiocyanate (FITC)-labeled dextran, as PLY accumulates in the cytoplasm. In contrast, the PLY-dependent execution of apoptosis requires phagocytosis and is part of a host response to intracellular bacteria that also includes NO generation. In cells challenged with PLY-deficient bacteria, reconstitution of LMP using the lysomotrophic detergent LeuLeuOMe favored cell necrosis whereas PLY reconstituted apoptosis. The results suggest that PLY contributes to macrophage activation and cytokine production but also engages LMP. Following bacterial phagocytosis, PLY triggers apoptosis and prevents macrophage necrosis as a component of a broad-based antimicrobial strategy. This illustrates how a key virulence factor can become the focus of a multilayered and coordinated innate response by macrophages, optimizing pathogen clearance and limiting inflammation. Importance: Streptococcus pneumoniae, the commonest cause of bacterial pneumonia, expresses the toxin pneumolysin, which can make holes in cell surfaces, causing tissue damage. Macrophages, resident immune cells essential for responses to bacteria in tissues, activate a program of cell suicide called apoptosis, maximizing bacterial clearance and limiting harmful inflammation. We examined pneumolysin's role in activating this response. We demonstrate that pneumolysin did not directly form holes in cells to trigger apoptosis and show that pneumolysin has two distinct roles which require only part of the molecule. Pneumolysin and other bacterial factors released by bacteria that have not been eaten by macrophages activate macrophages to release inflammatory factors but also make the cell compartment containing ingested bacteria leaky. Once inside the cell, pneumolysin ensures that the bacteria activate macrophage apoptosis, rather than necrosis, enhancing bacterial killing and limiting inflammation. This dual response to pneumolysin is critical for an effective immune response to S. pneumoniae.
Collapse
|
80
|
The nuclear factor kappa B (NF-κB) activation is required for phagocytosis of staphylococcus aureus by RAW 264.7 cells. Exp Cell Res 2014; 327:256-63. [DOI: 10.1016/j.yexcr.2014.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/22/2014] [Accepted: 04/23/2014] [Indexed: 11/23/2022]
|
81
|
BDCA1-positive dendritic cells (DCs) represent a unique human myeloid DC subset that induces innate and adaptive immune responses to Staphylococcus aureus Infection. Infect Immun 2014; 82:4466-76. [PMID: 25114114 DOI: 10.1128/iai.01851-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Staphylococcus aureus bloodstream infection (bacteremia) is a major cause of morbidity and mortality and places substantial cost burdens on health care systems. The role of peripheral blood dendritic cells (PBDCs) in the immune responses against S. aureus infection has not been well characterized. In this study, we demonstrated that BDCA1(+) myeloid DCs (mDCs) represent a unique PBDC subset that can induce immune responses against S. aureus infection. BDCA1(+) mDCs could engulf S. aureus and strongly upregulated the expression of costimulatory molecules and production of proinflammatory cytokines. Furthermore, BDCA1(+) mDCs expressed high levels of major histocompatibility complex (MHC) class I and II molecules in response to S. aureus and greatly promoted proliferation and gamma interferon (IFN-γ) production in CD4 and CD8 T cells. Moreover, BDCA1(+) mDCs expressed higher levels of Toll-like receptor 2 (TLR-2) and scavenger receptor A (SR-A) than those on CD16(+) and BDCA3(+) mDCs, and these two receptors were both required for the recognition of S. aureus and the subsequent activation of BDCA1(+) mDCs. Finally, BDCA1(+) mDC-mediated immune responses against S. aureus were dependent on MyD88 signaling pathways. These results demonstrate that human BDCA1(+) mDCs represent a unique subset of mDCs that can respond to S. aureus to undergo maturation and activation and to induce Th1 and Tc1 immune responses.
Collapse
|
82
|
Distinct cytokine pattern in response to different bacterial pathogens in human brain abscess. J Neuroimmunol 2014; 273:96-102. [DOI: 10.1016/j.jneuroim.2014.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/12/2014] [Accepted: 05/15/2014] [Indexed: 11/18/2022]
|
83
|
Tang C, Li Y, Lin X, Ye J, Li W, He Z, Li F, Cai X. Prolactin increases tumor necrosis factor alpha expression in peripheral CD14 monocytes of patients with rheumatoid arthritis. Cell Immunol 2014; 290:164-8. [PMID: 24997655 DOI: 10.1016/j.cellimm.2014.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 05/23/2014] [Accepted: 06/17/2014] [Indexed: 11/29/2022]
Abstract
Tumor necrosis factor (TNF)-α is one of the major proinflammatory mediators of rheumatic arthritis (RA); the regulatory factors for TNF-α release is not fully understood. This study aims to investigate the role of prolactin receptor (PRLR) activation in regulating the expression and release of TNF-α from CD14(+) monocytes. The results showed that the expression of PRLR was detectable in CD14(+) monocytes of healthy subjects, which was markedly increased in RA patients. Exposure to PRL in the culture increased the expression and release of TNF-α from CD14(+) monocytes, which was abolished by the PRLR gene silencing or blocking the mitogen activated protein (MAPK) pathway. We conclude that exposure to PRL increases TNF-α release from CD14(+) monocytes of RA patients, which can be abolished by PRLR gene silencing or treating with MAPK inhibitor.
Collapse
Affiliation(s)
- Chun Tang
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Yun Li
- Department of Cardiothoracic Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiaojun Lin
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Jinghua Ye
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Weinian Li
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Zhixiang He
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Fangfei Li
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China
| | - Xiaoyan Cai
- Department of Rheumatology, Guangzhou First People's Hospital, Guangzhou Medical University, 1 Panfu Road, Guangzhou, China.
| |
Collapse
|
84
|
Sharif O, Gawish R, Warszawska JM, Martins R, Lakovits K, Hladik A, Doninger B, Brunner J, Korosec A, Schwarzenbacher RE, Berg T, Kralovics R, Colinge J, Mesteri I, Gilfillan S, Salmaggi A, Verschoor A, Colonna M, Knapp S. The triggering receptor expressed on myeloid cells 2 inhibits complement component 1q effector mechanisms and exerts detrimental effects during pneumococcal pneumonia. PLoS Pathog 2014; 10:e1004167. [PMID: 24945405 PMCID: PMC4055749 DOI: 10.1371/journal.ppat.1004167] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 04/07/2014] [Indexed: 11/18/2022] Open
Abstract
Phagocytosis and inflammation within the lungs is crucial for host defense during bacterial pneumonia. Triggering receptor expressed on myeloid cells (TREM)-2 was proposed to negatively regulate TLR-mediated responses and enhance phagocytosis by macrophages, but the role of TREM-2 in respiratory tract infections is unknown. Here, we established the presence of TREM-2 on alveolar macrophages (AM) and explored the function of TREM-2 in the innate immune response to pneumococcal infection in vivo. Unexpectedly, we found Trem-2(-/-) AM to display augmented bacterial phagocytosis in vitro and in vivo compared to WT AM. Mechanistically, we detected that in the absence of TREM-2, pulmonary macrophages selectively produced elevated complement component 1q (C1q) levels. We found that these increased C1q levels depended on peroxisome proliferator-activated receptor-δ (PPAR-δ) activity and were responsible for the enhanced phagocytosis of bacteria. Upon infection with S. pneumoniae, Trem-2(-/-) mice exhibited an augmented bacterial clearance from lungs, decreased bacteremia and improved survival compared to their WT counterparts. This work is the first to disclose a role for TREM-2 in clinically relevant respiratory tract infections and demonstrates a previously unknown link between TREM-2 and opsonin production within the lungs.
Collapse
MESH Headings
- Animals
- Apoptosis
- Cell Line, Transformed
- Cells, Cultured
- Complement C1q/genetics
- Complement C1q/metabolism
- Cytokines/metabolism
- Disease Models, Animal
- Female
- Lung/cytology
- Lung/immunology
- Lung/metabolism
- Lung/pathology
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/metabolism
- Macrophages, Alveolar/pathology
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Neutrophil Infiltration
- PPAR gamma/metabolism
- Phagocytosis
- Pneumonia, Pneumococcal/immunology
- Pneumonia, Pneumococcal/metabolism
- Pneumonia, Pneumococcal/pathology
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Respiratory Mucosa/cytology
- Respiratory Mucosa/immunology
- Respiratory Mucosa/metabolism
- Respiratory Mucosa/pathology
- Survival Analysis
Collapse
Affiliation(s)
- Omar Sharif
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
- * E-mail: (OS); (SK)
| | - Riem Gawish
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Joanna M. Warszawska
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Rui Martins
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Karin Lakovits
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Anastasiya Hladik
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Bianca Doninger
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Julia Brunner
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Ana Korosec
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Roland E. Schwarzenbacher
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
| | - Tiina Berg
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Robert Kralovics
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Jacques Colinge
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Ildiko Mesteri
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Susan Gilfillan
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andrea Salmaggi
- Department of Clinical Neurosciences, Istituto Nazionale Neurologico Carlo Besta, Milano, Italy
| | - Admar Verschoor
- Institute for Medical Microbiology, Immunology and Hygiene, Technical University Munich, Munich, Germany
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sylvia Knapp
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Medicine I, Laboratory of Infection Biology, Medical University of Vienna, Vienna, Austria
- * E-mail: (OS); (SK)
| |
Collapse
|
85
|
Skjeflo EW, Christiansen D, Espevik T, Nielsen EW, Mollnes TE. Combined inhibition of complement and CD14 efficiently attenuated the inflammatory response induced by Staphylococcus aureus in a human whole blood model. THE JOURNAL OF IMMUNOLOGY 2014; 192:2857-64. [PMID: 24516199 DOI: 10.4049/jimmunol.1300755] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The complement and TLR systems are activated in sepsis, contributing to an unfavorable inflammatory "storm." Combined inhibition of these systems has been documented to efficiently attenuate the inflammatory responses induced by Gram-negative bacteria. In this study, we hypothesized that the combined inhibition would attenuate the inflammatory responses induced by Gram-positive bacteria. Staphylococcus aureus bacteria (strains Cowan and Wood), as well as S. aureus cell wall lipoteichoic acid (LTA), were incubated in thrombin-inhibited human whole blood. Complement was inhibited at the level of C3 and C5, and the TLRs by inhibiting CD14 and TLR2. Thirty-four inflammatory markers were measured by multiplex technology and flow cytometry. Thirteen markers increased significantly in response to Cowan and Wood, and 12 in response to LTA. Combined inhibition with the C3 inhibitor compstatin and the anti-CD14 Ab 18D11 significantly reduced 92 (Cowan, LTA) and 85% (Wood) of these markers. Compstatin alone significantly reduced 54 (Cowan), 38 (Wood), and 83% (LTA), whereas anti-CD14 alone significantly reduced 23, 15, and 67%, respectively. Further experiments showed that the effects of complement inhibition were mainly due to inhibition of C5a interaction with the C5a receptor. The effects on inhibiting CD14 and TLR2 were similar. The combined regimen was more efficient toward the bacterial effects than either complement or anti-CD14 inhibition alone. Complement was responsible for activation of and phagocytosis by both granulocytes and monocytes. Disrupting upstream recognition by inhibiting complement and CD14 efficiently attenuated S. aureus-induced inflammation and might be a promising treatment in both Gram-negative and Gram-positive sepsis.
Collapse
|
86
|
Blanchet C, Jouvion G, Fitting C, Cavaillon JM, Adib-Conquy M. Protective or deleterious role of scavenger receptors SR-A and CD36 on host resistance to Staphylococcus aureus depends on the site of infection. PLoS One 2014; 9:e87927. [PMID: 24498223 PMCID: PMC3909292 DOI: 10.1371/journal.pone.0087927] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 01/01/2014] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus is a major human opportunistic pathogen responsible for a broad spectrum of infections ranging from benign skin infection to more severe life threatening disorders (e.g. pneumonia, sepsis), particularly in intensive care patients. Scavenger receptors (SR-A and CD36) are known to be involved in S. aureus recognition by immune cells in addition to MARCO, TLR2, NOD2 and α5β1 integrin. In the present study, we further deciphered the contribution of SR-A and CD36 scavenger receptors in the control of infection of mice by S. aureus. Using double SR-A/CD36 knockout mice (S/C-KO) and S. aureus strain HG001, a clinically relevant non-mutagenized strain, we showed that the absence of these two scavenger receptors was protective in peritoneal infection. In contrast, the deletion of these two receptors was detrimental in pulmonary infection following intranasal instillation. For pulmonary infection, susceptible mice (S/C-KO) had more colony-forming units (CFU) in their broncho-alveolar lavages fluids, associated with increased recruitment of macrophages and neutrophils. For peritoneal infection, susceptible mice (wild-type) had more CFU in their blood, but recruited less macrophages and neutrophils in the peritoneal cavity than resistant mice. Exacerbated cytokine levels were often observed in the susceptible mice in the infected compartment as well as in the plasma. The exception was the enhanced compartmentalized expression of IL-1β for the resistant mice (S/C-KO) after peritoneal infection. A similar mirrored susceptibility to S. aureus infection was also observed for MARCO and TLR2. Marco and tlr2 -/- mice were more resistant to peritoneal infection but more susceptible to pulmonary infection than wild type mice. In conclusion, our results show that innate immune receptors can play distinct and opposite roles depending on the site of infection. Their presence is protective for local pulmonary infection, whereas it becomes detrimental in the peritoneal infection.
Collapse
Affiliation(s)
- Charlène Blanchet
- Institut Pasteur, Cytokines & Inflammation, Département Infection et Epidemiologie, Paris, France
| | - Gregory Jouvion
- Institut Pasteur, Unité d'Histopathologie humaine et modèles animaux, Département Infection et Epidemiologie, Paris, France
| | - Catherine Fitting
- Institut Pasteur, Cytokines & Inflammation, Département Infection et Epidemiologie, Paris, France
| | - Jean-Marc Cavaillon
- Institut Pasteur, Cytokines & Inflammation, Département Infection et Epidemiologie, Paris, France
- * E-mail:
| | - Minou Adib-Conquy
- Institut Pasteur, Cytokines & Inflammation, Département Infection et Epidemiologie, Paris, France
| |
Collapse
|
87
|
TLR2 ligands induce NF-κB activation from endosomal compartments of human monocytes. PLoS One 2013; 8:e80743. [PMID: 24349012 PMCID: PMC3861177 DOI: 10.1371/journal.pone.0080743] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/06/2013] [Indexed: 11/24/2022] Open
Abstract
Localization of Toll-like receptors (TLR) in subcellular organelles is a major strategy to regulate innate immune responses. While TLR4, a cell-surface receptor, signals from both the plasma membrane and endosomal compartments, less is known about the functional role of endosomal trafficking upon TLR2 signaling. Here we show that the bacterial TLR2 ligands Pam3CSK4 and LTA activate NF-κB-dependent signaling from endosomal compartments in human monocytes and in a NF-κB sensitive reporter cell line, despite the expression of TLR2 at the cell surface. Further analyses indicate that TLR2-induced NF-κB activation is controlled by a clathrin/dynamin-dependent endocytosis mechanism, in which CD14 serves as an important upstream regulator. These findings establish that internalization of cell-surface TLR2 into endosomal compartments is required for NF-κB activation. These observations further demonstrate the need of endocytosis in the activation and regulation of TLR2-dependent signaling pathways.
Collapse
|
88
|
Aberdein JD, Cole J, Bewley MA, Marriott HM, Dockrell DH. Alveolar macrophages in pulmonary host defence the unrecognized role of apoptosis as a mechanism of intracellular bacterial killing. Clin Exp Immunol 2013; 174:193-202. [PMID: 23841514 DOI: 10.1111/cei.12170] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2013] [Indexed: 01/12/2023] Open
Abstract
Alveolar macrophages play an essential role in clearing bacteria from the lower airway, as the resident phagocyte alveolar macrophages must both phagocytose and kill bacteria, and if unable to do this completely must co-ordinate an inflammatory response. The decision to escalate the inflammatory response represents the transition between subclinical infection and the development of pneumonia. Alveolar macrophages are well equipped to phagocytose bacteria and have a large phagolysosomal capacity in which ingested bacteria are killed. The rate-limiting step in control of extracellular bacteria, such as Streptococcus pneumoniae, is the capacity of alveolar macrophages to kill ingested bacteria. Therefore, alveolar macrophages complement canonical microbicidal strategies with an additional level of apoptosis-associated killing to help kill ingested bacteria.
Collapse
Affiliation(s)
- J D Aberdein
- Department of Infection and Immunity, University of Sheffield Medical School and Sheffield Teaching Hospitals, Sheffield, UK
| | | | | | | | | |
Collapse
|
89
|
Müller S, Faulhaber A, Sieber C, Pfeifer D, Hochberg T, Gansz M, Deshmukh SD, Dauth S, Brix K, Saftig P, Peters C, Henneke P, Reinheckel T. The endolysosomal cysteine cathepsins L and K are involved in macrophage-mediated clearance of Staphylococcus aureus and the concomitant cytokine induction. FASEB J 2013; 28:162-75. [PMID: 24036885 DOI: 10.1096/fj.13-232272] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cysteine cathepsins are endolysosomal cysteine proteases highly expressed in macrophages; however, their individual contributions to the elimination of bacteria and bacteria-induced cytokine production by macrophages are unknown. We assessed the contribution of cysteine cathepsins to macrophage defense pathways against Staphylococcus aureus by using chemical inhibitors and by infecting primary bone marrow-derived macrophages deficient in 1 of 7 major macrophage-expressed endolysosomal cysteine proteases. We show that cysteine cathepsins are involved in the phagocytosis and killing of S. aureus. Cathepsin L was identified as an executor of nonoxidative killing. Moreover, microarray data revealed cysteine cathepsins to be important for the maximal induction of certain proinflammatory genes, such as IL6, in response to S. aureus. Cysteine cathepsin's contribution to IL6 production was dependent on phagocytosis, and cathepsin K was identified to be a critical protease in this process. Analysis of macrophages with impaired trafficking of endolysosomal Toll-like receptors (TLRs) to the acidic compartment revealed that they were not involved in cathepsin-dependent IL6 induction. Because IL6 production was completely dependent on the TLR-adaptor protein myeloid differentiation primary response gene 88 (MyD88), it appears that other TLRs are involved. In summary, lysosomal cysteine proteases are functionally linked to the complex bactericidal and inflammatory activities of macrophages.
Collapse
Affiliation(s)
- Sabrina Müller
- 1Institute of Molecular Medicine and Cell Research, Stefan-Meier Str. 17, 79104 Freiburg, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
90
|
Onogawa T, Saito-Taki T, Yamamoto H, Wada T. IL6 trans-signaling promotes functional recovery of hypofunctional phagocytes through STAT3 activation during peritonitis. Inflamm Res 2013; 62:797-810. [PMID: 23732361 DOI: 10.1007/s00011-013-0637-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 04/22/2013] [Accepted: 05/14/2013] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE The role of high interleukin 6 (IL6) levels has not been clearly explained in severe sepsis. We show that the augmentation of the IL6 signal by recombinant IL6 receptors (rIL6R) delivery allows the functional recovery of phagocytes in a peritonitis mouse model. MATERIALS AND METHODS Mice were challenged intraperitoneally (i.p.) with live Staphylococcus aureus for effect of IL6R delivery on the 24 h-survival, bacterial clearance and cellular responses. In additional experiments to assess the effect of IL6R delivery on phagocytosis, the model was i.p. inoculated with heat-killed S. aureus with or without rIL6R and the peritoneal lavage fluid and cells were collected at 1 h after the i.p. inoculation of S. aureus. RESULTS The IL6R delivery tended to improve 24 h survival and increase bacteria clearance from the septic mice. The rIL6R treatment to heat-killed bacteria challenged mice augmented the uptake of bacteria and phagosome acidification, inducing the phosphorylation of STAT3 in peritoneal cells within 1 h after the IL6R delivery. Furthermore, the rIL6R delivery prevented the extracellular release of neutrophil elastase activity and myeloperoxidase (harmful factors). CONCLUSIONS These results indicate that augmentation of IL6 signaling appears to be critical for the effective management of hypofunctional neutrophils during severe inflammation, such as sepsis.
Collapse
Affiliation(s)
- Tsuyoshi Onogawa
- Medical Technology Education Unit, Kyorin University Faculty of Health Sciences, 476 Miyashita, Hachioji, Tokyo 192-8508, Japan.
| | | | | | | |
Collapse
|
91
|
Sokolovska A, Becker CE, Ip WKE, Rathinam VAK, Brudner M, Paquette N, Tanne A, Vanaja SK, Moore KJ, Fitzgerald KA, Lacy-Hulbert A, Stuart LM. Activation of caspase-1 by the NLRP3 inflammasome regulates the NADPH oxidase NOX2 to control phagosome function. Nat Immunol 2013; 14:543-53. [PMID: 23644505 PMCID: PMC3708594 DOI: 10.1038/ni.2595] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/28/2013] [Indexed: 11/10/2022]
Abstract
Phagocytosis is a fundamental cellular process that is pivotal for immunity as it coordinates microbial killing, innate immune activation and antigen presentation. An essential step in this process is phagosome acidification, which regulates many functions of these organelles that allow phagosomes to participate in processes that are essential to both innate and adaptive immunity. Here we report that acidification of phagosomes containing Gram-positive bacteria is regulated by the NLRP3 inflammasome and caspase-1. Active caspase-1 accumulates on phagosomes and acts locally to control the pH by modulating buffering by the NADPH oxidase NOX2. These data provide insight into a mechanism by which innate immune signals can modify cellular defenses and establish a new function for the NLRP3 inflammasome and caspase-1 in host defense.
Collapse
Affiliation(s)
- Anna Sokolovska
- Developmental Immunology and Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
92
|
Jung JY, Robinson CM. Interleukin-27 inhibits phagosomal acidification by blocking vacuolar ATPases. Cytokine 2013; 62:202-5. [PMID: 23557795 DOI: 10.1016/j.cyto.2013.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/25/2013] [Accepted: 03/08/2013] [Indexed: 01/10/2023]
Abstract
Interleukin (IL)-27 is a unique cytokine that has a dual role in immune responses. It was originally described to promote Th1 differentiation but also suppresses inflammation by inhibiting these and other inflammatory T cell subsets. Inhibition of inflammatory activity in macrophages has also been reported. These reports have largely focused on cytokine profiles or signaling mechanisms. To date, there have been no reports of how IL-27 may directly influence cellular mechanisms that operate to control microbial growth. Formation of a phagolysosome that acquires antimicrobial properties is an essential step for destruction of pathogens or pathogen-derived materials that are internalized by macrophages. Here we report that IL-27 has a profound influence on this critical innate immunity pathway. Treatment of human macrophages with IL-27 interferes with the acidification of phagosomes by reducing protein levels of V-ATPase and impairs control of bacterial pathogens.
Collapse
Affiliation(s)
- Joo-Yong Jung
- Department of Pathology, Microbiology, and Immunology, University of South Carolina, School of Medicine, Columbia, SC 29209, USA
| | | |
Collapse
|
93
|
Vaine CA, Patel MK, Zhu J, Lee E, Finberg RW, Hayward RC, Kurt-Jones EA. Tuning innate immune activation by surface texturing of polymer microparticles: the role of shape in inflammasome activation. THE JOURNAL OF IMMUNOLOGY 2013; 190:3525-32. [PMID: 23427254 PMCID: PMC3646559 DOI: 10.4049/jimmunol.1200492] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Polymeric microparticles have been widely investigated as platforms for delivery of drugs, vaccines, and imaging contrast agents and are increasingly used in a variety of clinical applications. Microparticles activate the inflammasome complex and induce the processing and secretion of IL-1β, a key innate immune cytokine. Recent work suggests that although receptors are clearly important for particle phagocytosis, other physical characteristics, especially shape, play an important role in the way microparticles activate cells. We examined the role of particle surface texturing not only on uptake efficiency but also on the subsequent immune cell activation of the inflammasome. Using a method based on emulsion processing of amphiphilic block copolymers, we prepared microparticles with similar overall sizes and surface chemistries but having either smooth or highly microtextured surfaces. In vivo, textured (budding) particles induced more rapid neutrophil recruitment to the injection site. In vitro, budding particles were more readily phagocytosed than smooth particles and induced more lipid raft recruitment to the phagosome. Remarkably, budding particles also induced stronger IL-1β secretion than smooth particles through activation of the NLRP3 inflammasome. These findings demonstrate a pronounced role of particle surface topography in immune cell activation, suggesting that shape is a major determinant of inflammasome activation.
Collapse
Affiliation(s)
- Christine A Vaine
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | | | | | | | | | | |
Collapse
|
94
|
Fournier B. The function of TLR2 during staphylococcal diseases. Front Cell Infect Microbiol 2013; 2:167. [PMID: 23316483 PMCID: PMC3539681 DOI: 10.3389/fcimb.2012.00167] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/11/2012] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus is a versatile pathogen causing a wide range of infections. It has been a major threat both in hospitals and in the community for decades. S. aureus is a pyogenic bacterium that elicits recruitment of polymorphonuclear leukocytes (neutrophils) to the site of infection. Neutrophils are among the first immune cells to migrate to an infection site attracted by chemoattractant gradients, usually initiated in response to inflammation. Neutrophil recruitment to an inflammation and/or infection site is a sophisticated process involving their interaction with endothelial and epithelial cells through adhesion molecules. Phagocytes have various receptors to detect pathogens, and they include Toll-like receptors (TLRs). TLRs have been extensively studied over the last 10 years and it is now established that they are critical during bacterial infections. However, the function of TLRs, and more particularly TLR2, during staphylococcal infections is still debated. In this review we will consider recent findings concerning the staphylococcal ligands sensed by TLR2 and more specifically the role of staphylococcal lipoproteins in TLR2 recognition. A new concept to emerge in recent years is that staphylococcal components must be phagocytosed and digested in the phagosome to be efficiently detected by the TLR2 of professional phagocytes. Neutrophils are an essential part of the immune response to staphylococcal infections, and in the second part of this review we will therefore describe the role of TLR2 in PMN recruitment in response to staphylococcal infections.
Collapse
Affiliation(s)
- Bénédicte Fournier
- Epithelial Pathobiology Research Unit, Department of Pathology and Laboratory Medicine, Emory University School of Medicine Atlanta, GA, USA. ;
| |
Collapse
|
95
|
TRIF mediates Toll-like receptor 2-dependent inflammatory responses to Borrelia burgdorferi. Infect Immun 2012; 81:402-10. [PMID: 23166161 DOI: 10.1128/iai.00890-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
TRIF is an adaptor molecule important in transducing signals from intracellularly signaling Toll-like receptor 3 (TLR3) and TLR4. Recently, TLR2 was found to signal from intracellular compartments. Using a synthetic ligand for TLR2/1 heterodimers, as well as Borrelia burgdorferi, which is a strong activator of TLR2/1, we found that TLR2 signaling can utilize TRIF. Unlike TRIF signaling by other TLRs, TLR2-mediated TRIF signaling is dependent on the presence of another adaptor molecule, MyD88. However, unlike MyD88 deficiency, TRIF deficiency does not result in diminished control of infection with B. burgdorferi in a murine model of disease. This appears to be due to the effects of MyD88 on phagocytosis via scavenger receptors, such as MARCO, which are not affected by the loss of TRIF. In mice, TRIF deficiency did have an effect on the production of inflammatory cytokines, suggesting that regulation of inflammatory cytokines and control of bacterial growth may be uncoupled, in part through transduction of TLR2 signaling through TRIF.
Collapse
|
96
|
Nakayama M, Kurokawa K, Nakamura K, Lee BL, Sekimizu K, Kubagawa H, Hiramatsu K, Yagita H, Okumura K, Takai T, Underhill DM, Aderem A, Ogasawara K. Inhibitory receptor paired Ig-like receptor B is exploited by Staphylococcus aureus for virulence. THE JOURNAL OF IMMUNOLOGY 2012; 189:5903-11. [PMID: 23152562 DOI: 10.4049/jimmunol.1201940] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The innate immune system has developed to acquire a wide variety of pattern-recognition receptors (PRRs) to identify potential pathogens, whereas pathogens have also developed to escape host innate immune responses. ITIM-bearing receptors are attractive targets for pathogens to attenuate immune responses against them; however, the in vivo role of the inhibitory PRRs in host-bacteria interactions remains unknown. We demonstrate in this article that Staphylococcus aureus, a major Gram-positive bacteria, exploits inhibitory PRR paired Ig-like receptor (PIR)-B on macrophages to suppress ERK1/2 and inflammasome activation, and subsequent IL-6 and IL-1β secretion. Consequently, Pirb(-/-) mice infected with S. aureus showed enhanced inflammation and more effective bacterial clearance, resulting in resistance to the sepsis. Screening of S. aureus mutants identified lipoteichoic acid (LTA) as an essential bacterial cell wall component required for binding to PIR-B and modulating inflammatory responses. In vivo, however, an LTA-deficient S. aureus mutant was highly virulent and poorly recognized by macrophages in both wild-type and Pirb(-/-) mice, demonstrating that LTA recognition by PRRs other than PIR-B mediates effective bacterial elimination. These results provide direct evidence that bacteria exploit the inhibitory receptor for virulence, and host immune system counterbalances the infection.
Collapse
Affiliation(s)
- Masafumi Nakayama
- Department of Immunobiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
97
|
Nakayama H, Kurokawa K, Lee BL. Lipoproteins in bacteria: structures and biosynthetic pathways. FEBS J 2012; 279:4247-68. [PMID: 23094979 DOI: 10.1111/febs.12041] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/02/2012] [Accepted: 10/19/2012] [Indexed: 11/29/2022]
Abstract
Bacterial lipoproteins are characterized by the presence of a conserved N-terminal lipid-modified cysteine residue that allows the hydrophilic protein to anchor onto bacterial cell membranes. These proteins play important roles in a wide variety of bacterial physiological processes, including virulence, and induce innate immune reactions by functioning as ligands of the mammalian Toll-like receptor 2. We review recent advances in our understanding of bacterial lipoprotein structure, biosynthesis and structure-function relationships between bacterial lipoproteins and Toll-like receptor 2. Notably, 40 years after the first report of the triacyl structure of Braun's lipoprotein in Escherichia coli, recent intensive MS-based analyses have led to the discovery of three new lipidated structures of lipoproteins in monoderm bacteria: the lyso, N-acetyl and peptidyl forms. Moreover, the bacterial lipoprotein structure is considered to be constant in each bacterium; however, lipoprotein structures in Staphylococcus aureus vary between the diacyl and triacyl forms depending on the environmental conditions. Thus, the lipidation state of bacterial lipoproteins, particularly in monoderm bacteria, is more complex than previously assumed.
Collapse
Affiliation(s)
- Hiroshi Nakayama
- Biomolecular Characterization Team, RIKEN Advanced Science Institute, Wako, Saitama, Japan.
| | | | | |
Collapse
|
98
|
Sokolovska A, Becker CE, Stuart LM. Measurement of phagocytosis, phagosome acidification, and intracellular killing of Staphylococcus aureus. CURRENT PROTOCOLS IN IMMUNOLOGY 2012; Chapter 14:14.30.1-14.30.12. [PMID: 23129153 DOI: 10.1002/0471142735.im1430s99] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phagocytes are an important part of host defense, playing a critical role in innate immune responses against pathogens and in the initiation of adaptive immunity. One of the main characteristics of these cells is their ability to recognize and internalize invading microorganisms into a phagosome. The internalized microbe is rapidly delivered into a mature phagolysosome where it is killed and degraded. However, numerous pathogens have evolved complex mechanisms to manipulate these intracellular organelles to establish a survival niche. Here, we describe several methods to assess important properties of phagosomes in macrophages, such as phagocytosis, acidification of the phagosome contents during the maturation process, and the ability of phagosomes to inactivate and kill pathogens. Phagocytosis and phagosome acidification assays are FACS-based assays where labeled bacteria are used as probes to monitor internalization into a phagosome and to detect the pH of the phagosome environment. The killing assay is based on the counting of bacterial colonies after recovery of internalized bacteria from macrophages.
Collapse
Affiliation(s)
- Anna Sokolovska
- Developmental Immunology/CCIB Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Christine E Becker
- Developmental Immunology/CCIB Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts
| | - Lynda M Stuart
- Developmental Immunology/CCIB Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| |
Collapse
|
99
|
Kenzel S, Mergen M, von Süßkind-Schwendi J, Wennekamp J, Deshmukh SD, Haeffner M, Triantafyllopoulou A, Fuchs S, Farmand S, Santos-Sierra S, Seufert J, van den Berg TK, Kuijpers TW, Henneke P. Insulin modulates the inflammatory granulocyte response to streptococci via phosphatidylinositol 3-kinase. THE JOURNAL OF IMMUNOLOGY 2012; 189:4582-91. [PMID: 23018458 DOI: 10.4049/jimmunol.1200205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Group B streptococci (GBS; Streptococcus agalactiae) are a major cause of invasive infections in newborn infants and in patients with type 2 diabetes. Both patient groups exhibit peripheral insulin resistance and alterations in polymorphonuclear leukocyte (PML) function. In this investigation, we studied the PML response repertoire to GBS with a focus on TLR signaling and the modulation of this response by insulin in mice and humans. We found that GBS-induced, MyD88-dependent chemokine formation of PML was specifically downmodulated by insulin via insulin receptor-mediated induction of PI3K. PI3K inhibited transcription of chemokine genes on the level of NF-κB activation and binding. Insulin specifically modulated the chemokine response of PML to whole bacteria, but affected neither activation by purified TLR agonists nor antimicrobial properties, such as migration, phagocytosis, bacterial killing, and formation of reactive oxygen species. The targeted modulation of bacteria-induced chemokine formation by insulin via PI3K may form a basis for the development of novel targets of adjunctive sepsis therapy.
Collapse
Affiliation(s)
- Sybille Kenzel
- Center for Pediatric and Adolescent Medicine, University of Freiburg, 79106 Freiburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
100
|
Kaplan A, Ma J, Kyme P, Wolf AJ, Becker CA, Tseng CW, Liu GY, Underhill DM. Failure to induce IFN-β production during Staphylococcus aureus infection contributes to pathogenicity. THE JOURNAL OF IMMUNOLOGY 2012; 189:4537-45. [PMID: 23008447 DOI: 10.4049/jimmunol.1201111] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The importance of type I IFNs in the host response to viral infection is well established; however, their role in bacterial infection is not fully understood. Several bacteria (both Gram-positive and -negative) have been shown to induce IFN-β production in myeloid cells, but this IFN-β is not always beneficial to the host. We examined whether Staphylococcus aureus induces IFN-β from myeloid phagocytes, and if so, whether it is helpful or harmful to the host to do so. We found that S. aureus poorly induces IFN-β production compared with other bacteria. S. aureus is highly resistant to degradation in the phagosome because it is resistant to lysozyme. Using a mutant that is more sensitive to lysozyme, we show that phagosomal degradation and release of intracellular ligands is essential for induction of IFN-β and inflammatory chemokines downstream of IFN-β. Further, we found that adding exogenous IFN-β during S. aureus infection (in vitro and in vivo) was protective. Together, the data demonstrate that failure to induce IFN-β production during S. aureus infection contributes to pathogenicity.
Collapse
Affiliation(s)
- Amber Kaplan
- Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | | | | | | | | | | | | | | |
Collapse
|