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Yan Q, Jia S, Li D, Yang J. The role and mechanism of action of microbiota-derived short-chain fatty acids in neutrophils: From the activation to becoming potential biomarkers. Biomed Pharmacother 2023; 169:115821. [PMID: 37952355 DOI: 10.1016/j.biopha.2023.115821] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/27/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023] Open
Abstract
Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, have emerged as critical mediators in the communication between the human microbiota and its host. As the first responder to the inflammatory site, neutrophils play an important role in protecting the host against bacterial infections. Recent investigations revealed that SCFAs generated from microbiota influence various neutrophil activities, including activation, migration, and generation of mediators of inflammatory processes. SCFAs have also been demonstrated to exhibit potential therapeutic benefits in a variety of disorders related to neutrophil dysfunction, including inflammatory bowel disease, viral infectious disorders, and cancer. This study aims to examine the molecular processes behind the complicated link between SCFAs and neutrophils, as well as their influence on neutrophil-driven inflammatory disorders. In addition, we will also provide an in-depth review of current research on the diagnostic and therapeutic value of SCFAs as possible biomarkers for neutrophil-related diseases.
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Affiliation(s)
- Qingzhu Yan
- Department of Ultrasound Medicine, the Second Hospital of Jilin University, Changchun 130000, China
| | - Shengnan Jia
- Digestive Diseases Center, Department of Hepatopancreatobiliary Medicine, the Second Hospital of Jilin University, Changchun 130000, China
| | - Dongfu Li
- Digestive Diseases Center, Department of Hepatopancreatobiliary Medicine, the Second Hospital of Jilin University, Changchun 130000, China.
| | - Junling Yang
- Department of Respiratory Medicine, the Second Hospital of Jilin University, Changchun 130000, China.
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2
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Moore SR, Menon SS, Galwankar NS, Khuder SA, Pangburn MK, Ferreira VP. A novel assay that characterizes properdin function shows neutrophil-derived properdin has a distinct oligomeric distribution. Front Immunol 2023; 13:918856. [PMID: 36713423 PMCID: PMC9880526 DOI: 10.3389/fimmu.2022.918856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023] Open
Abstract
Properdin acts as an essential positive regulator of the alternative pathway of complement by stabilizing enzymatic convertases. Identical properdin monomers form head-to-tail associations of oligomers in a reported 20:54:26 ratio (most often described as an approximate 1:2:1 ratio) of tetramers (P4), trimers (P3), and dimers (P2), in blood, under normal physiological conditions. Oligomeric size is proportional to properdin function with tetramers being more active, followed by trimers and dimers. Neutrophils are the most abundant granulocyte, are recruited to inflammatory microenvironments, and are a significant source of properdin, yet the ratio of properdin oligomers released from neutrophils is unknown. The oligomer ratio of neutrophil-derived properdin could have functional consequences in local microenvironments where neutrophils are abundant and complement drives inflammation. We investigated the oligomer properties of neutrophil-derived properdin, as compared to that of normal human sera, using a novel ELISA-based method that detects function of properdin in a way that was proportional to the oligomeric size of properdin (i.e., the larger the oligomer, the higher the detected function). Unexpectedly, neutrophil-derived properdin had 5-fold lower function than donor-matched serum-derived properdin. The lower function was due to a lower percentage of tetramers/trimers and more dimers, indicating a significantly different P4:P3:P2 ratio in neutrophil-derived properdin (18:34:48) as compared to donor-matched serum (29:43:29). Release of lower-order oligomers by neutrophils may constitute a novel regulatory mechanism to control the rate of complement activation in cellular microenvironments. Further studies to determine the factors that affect properdin oligomerization and whether, or how, the predominant dimers in neutrophil-derived properdin, assimilate to the ~1:2:1 ratio found in serum are warranted.
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Affiliation(s)
- Sara R. Moore
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Smrithi S. Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Neeti S. Galwankar
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Sadik A. Khuder
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Michael K. Pangburn
- Center for Biomedical Research, University of Texas Health Science Center, Tyler, TX, United States
| | - Viviana P. Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States,*Correspondence: Viviana P. Ferreira,
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3
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Pan W, Zhao Z, Wu J, Fan Q, Huang H, He R, Shen H, Zhao Z, Feng S, Gan G, Chen Z, Ma M, Sun C, Zhang L. LACpG10-HL Functions Effectively in Antibiotic-Free and Healthy Husbandry by Improving the Innate Immunity. Int J Mol Sci 2022; 23:ijms231911466. [PMID: 36232768 PMCID: PMC9569488 DOI: 10.3390/ijms231911466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 12/05/2022] Open
Abstract
Antibiotics are broadly restricted in modern husbandry farming, necessitating the need for efficient and low-cost immunomodulatory preparations in antibiotic-free and healthful farming. As is known to all, CpG oligonucleotides (CpG-ODNs, an effective innate immunostimulatory agent) recognized by TLR9 in mammals (while TLR21 in avians) could collaborate with some united agent to induce stronger immune responses, but the cost is prohibitively expensive for farmers. Here, considering the coordination between TLR2 and TLR9/TLR21, we firstly proposed the idea that the well-fermented Lactococcus lactis could be utilized as a CpG-plasmid carrier (LACpG10) to enhance the host’s innate immunity against pathogenic invasion. In the present study, after obtaining LACpG10-HL from homogenized and lyophilized recombinant strain LACpG10, we treated primary chicken lymphocytes, two cell lines (HD11 and IPEC-J2), and chickens with LACpG10-HL, CpG plasmids (pNZ8148-CpG10), and other stimulants, and respectively confirmed the effects by conducting qRT-PCR, bacterial infection assays, and a zoological experiment. Our data showed that LACpG10-HL could induce excellent innate immunity by regulating autophagy reactions, cytokine expression, and motivating PRRs. Interestingly, despite having no direct antiseptic effect, LACpG10-HL improved the antibacterial capacities of lymphocytes and enterocytes at the first line of defense. Most importantly, water-supplied LACpG10-HL treatment reduced the average adverse event rates, demonstrating that LACpG10-HL maintained its excellent immunostimulatory and protective properties under farming conditions. Our research not only contributes to revealing the satisfactory effects of LACpG10-HL but also sheds new light on a cost-effective solution with optimal immune effects in green, antibiotic-free, and healthful husbandry farming.
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4
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Abstract
The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.
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Affiliation(s)
- Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States.
| | - Caroline Desler
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Amanda Mazzoli
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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5
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Schlatterer K, Beck C, Schoppmeier U, Peschel A, Kretschmer D. Acetate sensing by GPR43 alarms neutrophils and protects from severe sepsis. Commun Biol 2021; 4:928. [PMID: 34330996 PMCID: PMC8324776 DOI: 10.1038/s42003-021-02427-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
Bacterial sepsis is a major cause of mortality resulting from inadequate immune responses to systemic infection. Effective immunomodulatory approaches are urgently needed but it has remained elusive, which targets might be suitable for intervention. Increased expression of the G-protein-coupled receptor GPR43, which is known to govern intestinal responses to acetate, has been associated with sepsis patient survival but the mechanisms behind this observation have remained unclear. We show that elevated serum acetate concentrations prime neutrophils in a GPR43-dependent fashion, leading to enhanced neutrophil chemotaxis, oxidative burst, cytokine release and upregulation of phagocytic receptors. Consequently, acetate priming improved the capacity of human neutrophils to eliminate methicillin-resistant Staphylococcus aureus. Acetate administration increased mouse serum acetate concentrations and primed neutrophils. Notably, it rescued wild-type mice from severe S. aureus sepsis and reduced bacterial numbers in peripheral organs by several magnitudes. Acetate treatment improved the sepsis course even when applied several hours after onset of the infection, which recommends GPR43 as a potential target for sepsis therapy. Our study indicates that the severity of sepsis depends on transient neutrophil priming by appropriate blood acetate concentrations. Therapeutic interventions based on GPR43 stimulation could become valuable strategies for reducing sepsis-associated morbidity and mortality.
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Affiliation(s)
- Katja Schlatterer
- grid.10392.390000 0001 2190 1447Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Infection Biology, University of Tübingen, Tübingen, Germany ,grid.452463.2German Center for Infection Research, partner site Tübingen, Tübingen, Germany ,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
| | - Christian Beck
- grid.10392.390000 0001 2190 1447Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Infection Biology, University of Tübingen, Tübingen, Germany ,grid.452463.2German Center for Infection Research, partner site Tübingen, Tübingen, Germany ,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
| | - Ulrich Schoppmeier
- grid.452463.2German Center for Infection Research, partner site Tübingen, Tübingen, Germany ,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany ,grid.10392.390000 0001 2190 1447Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Medical Microbiology and Hygiene, University of Tübingen, Tübingen, Germany
| | - Andreas Peschel
- grid.10392.390000 0001 2190 1447Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Infection Biology, University of Tübingen, Tübingen, Germany ,grid.452463.2German Center for Infection Research, partner site Tübingen, Tübingen, Germany ,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
| | - Dorothee Kretschmer
- grid.10392.390000 0001 2190 1447Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), Infection Biology, University of Tübingen, Tübingen, Germany ,grid.452463.2German Center for Infection Research, partner site Tübingen, Tübingen, Germany ,Cluster of Excellence EXC 2124 Controlling Microbes to Fight Infections, Tübingen, Germany
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6
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Cui G, Geng L, Zhu L, Lin Z, Liu X, Miao Z, Jiang J, Feng X, Wei F. CFP is a prognostic biomarker and correlated with immune infiltrates in Gastric Cancer and Lung Cancer. J Cancer 2021; 12:3378-3390. [PMID: 33976747 PMCID: PMC8100816 DOI: 10.7150/jca.50832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 03/21/2021] [Indexed: 01/06/2023] Open
Abstract
Complement factor properdin (CFP), encodes plasma glycoprotein, is a critical gene that regulates the complement pathway of the innate immune system. However, correlations of CFP in cancers remain unclear. In this study, the expression pattern and prognostic value of CFP in pan-cancer were analyzed via the Oncomine, PrognoScan, GEPIA and Kaplan-Meier plotters. In addition, we used immunohistochemical staining to validate CFP expression in clinical tissue samples. Finally, we evaluated the correlations between CFP and cancer immune infiltrates particularly in stomach adenocarcinoma (STAD) and lung adenocarcinoma (LUAD) by using GEPIA and TIMER databases. The results of database analysis and immunohistochemistry showed that the expression level of CFP in STAD and LUAD was lower than that in normal tissues. Low expression level of CFP was associated with poorer overall survival (OS), first progression (FP), post progression survival (PPS) and was detrimental to the prognosis of STAD and LUAD, specifically in stage 3, stage T3, stage N2 and N3 of STAD (P<0.05). Moreover, expression of CFP had significant positive correlations with the infiltration levels of CD8+ T cells, CD4+ T cells, macrophages, neutrophils and dendritic cells (DCs) in STAD and LUAD. Furthermore, gene markers of infiltrating immune cells exhibited different CFP-related immune infiltration patterns such as tumor-associated-macrophages (TAMs). These results suggest that CFP can serve as a prognostic biomarker for determining prognosis and immune infiltration in STAD and LUAD.
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Affiliation(s)
- Guoliang Cui
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China.,The Second Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210017, Jiangsu, China
| | - Le Geng
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Li Zhu
- The Second Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210017, Jiangsu, China
| | - Zhenyan Lin
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xuan Liu
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Zhengyue Miao
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Jintao Jiang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xiaoke Feng
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Fei Wei
- Department of Physiology, School of medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, Jiangsu, China
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7
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Jones NP. Immunosuppression in the Management of Presumed Non-infective Uveitis; Are We Sure What We are Treating? Notes on the Antimicrobial Properties of the Systemic Immunosuppressants. Ocul Immunol Inflamm 2020; 28:994-1003. [PMID: 31418624 DOI: 10.1080/09273948.2019.1643030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE To describe the antimicrobial effects of immunosuppressants used for presumed autoimmune uveitis, and to discuss the potential importance of these effects in the context of increasing knowledge of the human microbiomes and their influence on inflammation. METHODS Literature review. REVIEW OF EVIDENCE All immunosuppressants have intrinsic antimicrobial effects; these vary considerably between drugs, and include antibacterial, antiviral and antifungal action. Immunosuppression is known to affect the composition of the gut microbiome, and alterations in microbiome composition are known to affect inflammations including uveitis. CONCLUSIONS Oral immunosuppressants are assumed to act on presumed autoimmune uveitis by downregulation of, or other interference with, an aberrant immune response. However, their antimicrobial properties are usually forgotten, and in the context of increasing knowledge of the involvement of microbes in the initiation of, and also potentially the perpetuation of, tissue inflammation, these effects may prove to be a fundamental part of their action.
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Affiliation(s)
- Nicholas P Jones
- Manchester Royal Eye Hospital, Manchester University Hospitals NHS Foundation Trust , Manchester, UK.,Medical Academic Health Science Centre, University of Manchester , Manchester, UK
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8
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Keller N, Woytschak J, Heeb LEM, Marques Maggio E, Mairpady Shambat S, Snäll J, Hyldegaard O, Boyman O, Norrby-Teglund A, Zinkernagel AS. Group A Streptococcal DNase Sda1 Impairs Plasmacytoid Dendritic Cells' Type 1 Interferon Response. J Invest Dermatol 2019; 139:1284-93. [PMID: 30543898 DOI: 10.1016/j.jid.2018.11.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 01/19/2023]
Abstract
Group A Streptococcus causes severe invasive infections, including necrotizing fasciitis. The expression of an array of virulence factors targeting specific host immune functions impedes successful bacterial clearance. The virulence factor streptococcal DNase Sda1 was previously shown to interfere with the entrapment of bacteria through neutrophil extracellular traps and TLR9 signaling. In this study, we showed that plasmacytoid dendritic cells are recruited to the infected tissue during group A streptococcal necrotizing fasciitis. We found that the streptococcal DNase Sda1 impairs plasmacytoid dendritic cell recruitment by reducing IFN-1 levels at the site of infection. We found that streptococcal DNase Sda1 interferes with stabilization of the DNA by the host molecule HMGB1 protein, which may account for decreased IFN-1 levels at the site of infection.
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9
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Chen JY, Cortes C, Ferreira VP. Properdin: A multifaceted molecule involved in inflammation and diseases. Mol Immunol 2018; 102:58-72. [PMID: 29954621 DOI: 10.1016/j.molimm.2018.05.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 01/17/2023]
Abstract
Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.
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Affiliation(s)
- Jin Y Chen
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
| | - Claudio Cortes
- Department of Biomedical Sciences, University of Oakland University School of Medicine, Rochester, MI, United States.
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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10
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Baumann A, Kiener MS, Haigh B, Perreten V, Summerfield A. Differential Ability of Bovine Antimicrobial Cathelicidins to Mediate Nucleic Acid Sensing by Epithelial Cells. Front Immunol 2017; 8:59. [PMID: 28203238 PMCID: PMC5285380 DOI: 10.3389/fimmu.2017.00059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/16/2017] [Indexed: 12/26/2022] Open
Abstract
Cathelicidins encompass a family of cationic peptides characterized by antimicrobial activity and other functions, such as the ability to enhance the sensing of nucleic acids by the innate immune system. The present study aimed to investigate the ability of the bovine cathelicidins indolicidin, bactenecin (Bac)1, Bac5, bovine myeloid antimicrobial peptide (BMAP)-27, BMAP-28, and BMAP-34 to inhibit the growth of bacteria and to enhance the sensing of nucleic acid by the host’s immune system. BMAP-27 was the most effective at killing Staphylococcus aureus, Streptococcus uberis, and Escherichia coli, and this was dependent on its amphipathic structure and cationic charge. Although most cathelicidins possessed DNA complexing activity, only the alpha-helical BMAP cathelicidins and the cysteine-rich disulfide-bridged Bac1 were able to enhance the sensing of nucleic acids by primary epithelial cells. We also compared these responses with those mediated by neutrophils. Activation of neutrophils with phorbol myristate acetate resulted in degranulation and release of cathelicidins as well as bactericidal activity in the supernatants. However, only supernatants from unstimulated neutrophils were able to promote nucleic acid sensing in epithelial cells. Collectively, the present data support a role for certain bovine cathelicidins in helping the innate immune system to sense nucleic acids. The latter effect is observed at concentrations clearly below those required for direct antimicrobial functions. These findings are relevant in development of future strategies to promote protection at mucosal surfaces against pathogen invasion.
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Affiliation(s)
- Arnaud Baumann
- Institute of Virology and Immunology , Bern , Switzerland
| | | | - Brendan Haigh
- AgResearch, Ruakura Research Centre , Hamilton , New Zealand
| | - Vincent Perreten
- Vetsuisse Faculty, Department of Infectious Diseases and Pathobiology, Institute of Veterinary Bacteriology, University of Bern , Bern , Switzerland
| | - Artur Summerfield
- Institute of Virology and Immunology, Bern, Switzerland; Vetsuisse Faculty, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, Switzerland
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11
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Abstract
Defense against bacterial infections requires activation of the immune response as well as timely reestablishment of tissue and immune homeostasis. Instauration of homeostasis is critical for tissue regeneration, wound healing, and host recovery. Recent studies revealed that severe infectious diseases frequently result from failures in homeostatic processes rather than from inefficient pathogen eradication. Type I interferons (IFN) appear to play a key role in such processes. Remarkably, the involvement of type I IFNs in the regulation of immune and tissue homeostasis upon bacterial insult may have beneficial or detrimental consequences for the host. The reasons for such ambivalent function of type I IFNs are not understood. The disparate effects of type I IFNs on bacterial infections are in marked contrast to their well-established protective roles in most viral infections. In this review, we will focus on type I IFN effector mechanisms which balance processes involved in immune and tissue homeostasis during specific bacterial infections and highlight the most important missing links in our understanding of type I IFN functions.
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Affiliation(s)
- Pavel Kovarik
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | | | - Masa Ivin
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Florian Ebner
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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12
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Tsyrkunou A, Agarwal S, Koirala B, Finberg RW, Nath R, Barton B, Levitz SM, Wang JP, Ram S. Properdin Levels in Individuals with Chemotherapy-Induced Neutropenia. Open Forum Infect Dis 2016; 4:ofw250. [PMID: 28480246 PMCID: PMC5414105 DOI: 10.1093/ofid/ofw250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/19/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neutrophils produce and carry key components of the alternative pathway (AP) of complement, including properdin (P). The effect of chemotherapy-induced absolute neutropenia on circulating P levels and AP function has not been previously established. METHODS We prospectively measured free P levels in serum from 27 individuals expected to develop neutropenia after administration of chemotherapy for hematological malignancies in preparation for hematopoietic stem cell transplantation and here describe the relationship between serum P levels and the neutrophil count over time. RESULTS When the absolute neutrophil count (ANC) was >500 cells/mm3 pre-chemotherapy, P levels were significantly higher than P levels associated with an ANC ≤500 cells/mm3 (median values 8392 ng/mL and 6355 ng/mL, respectively; P = .001). Pairwise comparison between pre-chemotherapy P levels and P levels at initial or last documented neutropenia before recovery showed a significant decline (P < .0001). No correlation was observed between P levels during neutropenia and after recovery of neutropenia in 20 subjects for which postneutropenia samples were obtained. A small but significant (P = .02) decrease in AP hemolytic activity was noted between baseline (preneutropenia) and samples obtained at the onset of neutropenia, but only with low (6.25%) and not higher (12.5 or 25%) serum concentrations. CONCLUSIONS A decline in P levels and AP activity could contribute to the increased risk of infection in neutropenic patients and warrants further study.
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Affiliation(s)
- Artsiom Tsyrkunou
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Sarika Agarwal
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Bibek Koirala
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Robert W Finberg
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Rajneesh Nath
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Bruce Barton
- Departments of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester
| | - Stuart M Levitz
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Jennifer P Wang
- Departments of Medicine University of Massachusetts Medical School, Worcester
| | - Sanjay Ram
- Departments of Medicine University of Massachusetts Medical School, Worcester
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