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Ma YJ, Parente R, Zhong H, Sun Y, Garlanda C, Doni A. Complement-pentraxins synergy: Navigating the immune battlefield and beyond. Biomed Pharmacother 2023; 169:115878. [PMID: 37952357 DOI: 10.1016/j.biopha.2023.115878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023] Open
Abstract
The complement is a crucial immune defense system that triggers rapid immune responses and offers efficient protection against foreign invaders and unwanted host elements, acting as a sentinel. Activation of the complement system occurs upon the recognition of pathogenic microorganisms or altered self-cells by pattern-recognition molecules (PRMs) such as C1q, collectins, ficolins, and pentraxins. Recent accumulating evidence shows that pentraxins establish a cooperative network with different classes of effector PRMs, resulting in synergistic effects in complement activation. This review describes the complex interaction of pentraxins with the complement system and the implications of this cooperative network for effective host defense during pathogen invasion.
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Affiliation(s)
- Ying Jie Ma
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark.
| | | | - Hang Zhong
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy; Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Yi Sun
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark
| | - Cecilia Garlanda
- IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
| | - Andrea Doni
- IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy.
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2
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Massimino AM, Colella FE, Bottazzi B, Inforzato A. Structural insights into the biological functions of the long pentraxin PTX3. Front Immunol 2023; 14:1274634. [PMID: 37885881 PMCID: PMC10598717 DOI: 10.3389/fimmu.2023.1274634] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/27/2023] [Indexed: 10/28/2023] Open
Abstract
Soluble pattern recognition molecules (PRMs) are a heterogenous group of proteins that recognize pathogen- and danger-associated molecular patterns (PAMPs and DAMPs, respectively), and cooperate with cell-borne receptors in the orchestration of innate and adaptive immune responses to pathogenic insults and tissue damage. Amongst soluble PRMs, pentraxins are a family of highly conserved proteins with distinctive structural features. Originally identified in the early 1990s as an early inflammatory gene, PTX3 is the prototype of long pentraxins. Unlike the short pentraxin C reactive protein (CRP), whose expression is mostly confined to the liver, PTX3 is made by several immune and non-immune cells at sites of infection and inflammation, where it intercepts fundamental aspects of infection immunity, inflammation, and tissue remodeling. Of note, PTX3 cross talks to components of the complement system to control cancer-related inflammation and disposal of pathogens. Also, it is an essential component of inflammatory extracellular matrices (ECMs) through crosslinking of hyaluronic acid and turn-over of provisional fibrin networks that assemble at sites of tissue injury. This functional diversity is mediated by unique structural characteristics whose fine details have been unveiled only recently. Here, we revisit the structure/function relationships of this long pentraxin in light of the most recent advances in its structural biology, with a focus on the interplay with complement and the emerging roles as a component of the ECM. Differences to and similarities with the short pentraxins are highlighted and discussed.
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Affiliation(s)
| | | | - Barbara Bottazzi
- Laboratory of Cellular and Humoral Innate Immunity, IRCCS Humanitas Research Hospital, Rozzano, Italy
| | - Antonio Inforzato
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
- Laboratory of Cellular and Humoral Innate Immunity, IRCCS Humanitas Research Hospital, Rozzano, Italy
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3
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McCarthy WC, Sherlock LG, Grayck MR, Zheng L, Lacayo OA, Solar M, Orlicky DJ, Dobrinskikh E, Wright CJ. Innate Immune Zonation in the Liver: NF-κB (p50) Activation and C-Reactive Protein Expression in Response to Endotoxemia Are Zone Specific. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:1372-1385. [PMID: 36946778 PMCID: PMC10121917 DOI: 10.4049/jimmunol.2200900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023]
Abstract
Hepatic innate immune function plays an important role in the pathogenesis of many diseases. Importantly, a growing body of literature has firmly established the spatial heterogeneity of hepatocyte metabolic function; however, whether innate immune function is zonated remains unknown. To test this question, we exposed adult C57BL/6 mice to endotoxemia, and hepatic tissue was assessed for the acute phase response (APR). The zone-specific APR was evaluated in periportal and pericentral/centrilobular hepatocytes isolated using digitonin perfusion and on hepatic tissue using RNAscope and immunohistochemistry. Western blot, EMSA, chromatin immunoprecipitation, and immunohistochemistry were used to determine the role of the transcription factor NF-κB in mediating hepatic C-reactive protein (CRP) expression. Finally, the ability of mice lacking the NF-κB subunit p50 (p50-/-) to raise a hepatic APR was evaluated. We found that endotoxemia induces a hepatocyte transcriptional APR in both male and female mice, with Crp, Apcs, Fga, Hp, and Lbp expression being enriched in pericentral/centrilobular hepatocytes. Focusing our work on CRP expression, we determined that NF-κB transcription factor subunit p50 binds to consensus sequence elements present in the murine CRP promoter. Furthermore, pericentral/centrilobular hepatocyte p50 nuclear translocation is temporally associated with zone-specific APR during endotoxemia. Lastly, the APR and CRP expression is blunted in endotoxemic p50-/- mice. These results demonstrate that the murine hepatocyte innate immune response to endotoxemia includes zone-specific activation of transcription factors and target gene expression. These results support further study of zone-specific hepatocyte innate immunity and its role in the development of various disease states.
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Affiliation(s)
- William C. McCarthy
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Laura G. Sherlock
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Maya R. Grayck
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Lijun Zheng
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Oscar A. Lacayo
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - Mack Solar
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
| | - David J. Orlicky
- Dept of Pathology, University of Colorado Anschutz School of Medicine, Aurora, CO
| | - Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO
| | - Clyde J. Wright
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO
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4
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Characterization of the innate immune response to Streptococcus pneumoniae infection in zebrafish. PLoS Genet 2023; 19:e1010586. [PMID: 36622851 PMCID: PMC9858863 DOI: 10.1371/journal.pgen.1010586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 01/20/2023] [Accepted: 12/20/2022] [Indexed: 01/10/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is one of the most frequent causes of pneumonia, sepsis and meningitis in humans, and an important cause of mortality among children and the elderly. We have previously reported the suitability of the zebrafish (Danio rerio) larval model for the study of the host-pathogen interactions in pneumococcal infection. In the present study, we characterized the zebrafish innate immune response to pneumococcus in detail through a whole-genome level transcriptome analysis and revealed a well-conserved response to this human pathogen in challenged larvae. In addition, to gain understanding of the genetic factors associated with the increased risk for severe pneumococcal infection in humans, we carried out a medium-scale forward genetic screen in zebrafish. In the screen, we identified a mutant fish line which showed compromised resistance to pneumococcus in the septic larval infection model. The transcriptome analysis of the mutant zebrafish larvae revealed deficient expression of a gene homologous for human C-reactive protein (CRP). Furthermore, knockout of one of the six zebrafish crp genes by CRISPR-Cas9 mutagenesis predisposed zebrafish larvae to a more severe pneumococcal infection, and the phenotype was further augmented by concomitant knockdown of a gene for another Crp isoform. This suggests a conserved function of C-reactive protein in anti-pneumococcal immunity in zebrafish. Altogether, this study highlights the similarity of the host response to pneumococcus in zebrafish and humans, gives evidence of the conserved role of C-reactive protein in the defense against pneumococcus, and suggests novel host genes associated with pneumococcal infection.
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Zeller J, Cheung Tung Shing KS, Nero TL, McFadyen JD, Krippner G, Bogner B, Kreuzaler S, Kiefer J, Horner VK, Braig D, Danish H, Baratchi S, Fricke M, Wang X, Kather MG, Kammerer B, Woollard KJ, Sharma P, Morton CJ, Pietersz G, Parker MW, Peter K, Eisenhardt SU. A novel phosphocholine-mimetic inhibits a pro-inflammatory conformational change in C-reactive protein. EMBO Mol Med 2022; 15:e16236. [PMID: 36468184 PMCID: PMC9832874 DOI: 10.15252/emmm.202216236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/29/2022] [Accepted: 11/06/2022] [Indexed: 12/09/2022] Open
Abstract
C-reactive protein (CRP) is an early-stage acute phase protein and highly upregulated in response to inflammatory reactions. We recently identified a novel mechanism that leads to a conformational change from the native, functionally relatively inert, pentameric CRP (pCRP) structure to a pentameric CRP intermediate (pCRP*) and ultimately to the monomeric CRP (mCRP) form, both exhibiting highly pro-inflammatory effects. This transition in the inflammatory profile of CRP is mediated by binding of pCRP to activated/damaged cell membranes via exposed phosphocholine lipid head groups. We designed a tool compound as a low molecular weight CRP inhibitor using the structure of phosphocholine as a template. X-ray crystallography revealed specific binding to the phosphocholine binding pockets of pCRP. We provide in vitro and in vivo proof-of-concept data demonstrating that the low molecular weight tool compound inhibits CRP-driven exacerbation of local inflammatory responses, while potentially preserving pathogen-defense functions of CRP. The inhibition of the conformational change generating pro-inflammatory CRP isoforms via phosphocholine-mimicking compounds represents a promising, potentially broadly applicable anti-inflammatory therapy.
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Affiliation(s)
- Johannes Zeller
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany,Baker Heart and Diabetes InstituteMelbourneVic.Australia
| | - Karen S Cheung Tung Shing
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneParkvilleVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Tracy L Nero
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneParkvilleVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia,ACRF Rational Drug Discovery CentreSt. Vincent's Institute of Medical ResearchFitzroyVic.Australia
| | - James D McFadyen
- Baker Heart and Diabetes InstituteMelbourneVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Guy Krippner
- Baker Heart and Diabetes InstituteMelbourneVic.Australia
| | - Balázs Bogner
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - Sheena Kreuzaler
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - Jurij Kiefer
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - Verena K Horner
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - David Braig
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - Habiba Danish
- Baker Heart and Diabetes InstituteMelbourneVic.Australia,School of Health and Biomedical SciencesRMIT UniversityMelbourneVic.Australia
| | - Sara Baratchi
- School of Health and Biomedical SciencesRMIT UniversityMelbourneVic.Australia
| | - Mark Fricke
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
| | - Xiaowei Wang
- Baker Heart and Diabetes InstituteMelbourneVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Michel G Kather
- Centre for Integrative Signalling Analysis CISAUniversity of FreiburgFreiburgGermany
| | - Bernd Kammerer
- Centre for Integrative Signalling Analysis CISAUniversity of FreiburgFreiburgGermany
| | | | - Prerna Sharma
- Baker Heart and Diabetes InstituteMelbourneVic.Australia
| | - Craig J Morton
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneParkvilleVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Geoffrey Pietersz
- Baker Heart and Diabetes InstituteMelbourneVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Michael W Parker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneParkvilleVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia,ACRF Rational Drug Discovery CentreSt. Vincent's Institute of Medical ResearchFitzroyVic.Australia
| | - Karlheinz Peter
- Baker Heart and Diabetes InstituteMelbourneVic.Australia,Department of Cardiometabolic HealthThe University of MelbourneParkvilleVic.Australia
| | - Steffen U Eisenhardt
- Department of Plastic and Hand Surgery, University of Freiburg Medical CentreMedical Faculty of the University of FreiburgFreiburgGermany
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Kloss M, Moerke C, Woitschach F, Wulf K, Illner S, Schulz S, Pauker VI, Riedel K, Grabow N, Ince H, Reisinger EC, Sombetzki M. Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model. Front Bioeng Biotechnol 2022; 10:1021827. [DOI: 10.3389/fbioe.2022.1021827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/02/2022] [Indexed: 11/19/2022] Open
Abstract
Infective/bacterial endocarditis is a rare but life-threatening disease with a hospital mortality rate of 22.7% and a 1-year mortality rate of 40%. Therefore, continued research efforts to develop efficient anti-infective implant materials are of the utmost importance. Equally important is the development of test systems that allow the performance of new materials to be comprehensively evaluated. In this study, a novel antibacterial coating based on dalbavancin was tested in comparison to rifampicin/minocycline, and the suitability of a recently developed mouse tail vein model for testing the implant coatings was validated. Small polymeric stent grafts coated with a poly-L-lactic acid (PLLA) layer and incorporated antibiotics were colonized with Staphylococcus (S.) aureus before implantation into the tail vein of mice. The main assessment criteria were the hematogenous spread of the bacteria and the local tissue reaction to the contaminated implant. For this purpose, colony-forming units (CFU) in the blood, spleen and kidneys were determined. Tail cross sections were prepared for histological analysis, and plasma cytokine levels and expression values of inflammation-associated genes were examined. Both antibiotic coatings performed excellently, preventing the onset of infection. The present study expands the range of available methods for testing the anti-infectivity of cardiovascular implants, and the spectrum of agents for effective surface coating.
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Macrophage-Targeted Sodium Chlorite (NP001) Slows Progression of Amyotrophic Lateral Sclerosis (ALS) through Regulation of Microbial Translocation. Biomedicines 2022; 10:biomedicines10112907. [PMID: 36428474 PMCID: PMC9687998 DOI: 10.3390/biomedicines10112907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a heterogeneous, progressive, and universally fatal neurodegenerative disease. A subset of ALS patients has measurable plasma levels of lipopolysaccharide (LPS) and C-reactive protein (CRP) consistent with low-grade microbial translocation (MT). Unless interrupted, MT sets up a self-perpetuating loop of inflammation associated with systemic macrophage activation. To test whether MT contributed to ALS progression, blood specimens from a phase 2 study of NP001 in ALS patients were evaluated for changes in activity in treated patients as compared to controls over the 6-month study. In this post hoc analysis, plasma specimens from baseline and six-month timepoints were analyzed. Compared with baseline values, biomarkers related to MT were significantly decreased (LPS, LPS binding protein (LBP), IL-18, Hepatocyte growth factor (HGF), soluble CD163 (sCD163)) in NP001-treated patients as compared to controls, whereas wound healing and immunoregulatory factors were increased (IL-10, Epidermal growth factor (EGF), neopterin) by the end of study. These biomarker results linked to the positive clinical trial outcome confirm that regulation of macrophage activation may be an effective approach for the treatment of ALS and, potentially, other neuroinflammatory diseases related to MT.
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8
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Zhang Z, Gao Y, Li L, Luo J, Gao R. Deficiency of C-reactive protein or human C-reactive protein transgenic treatment aggravates influenza A infection in mice. Front Immunol 2022; 13:1028458. [PMID: 36275680 PMCID: PMC9584053 DOI: 10.3389/fimmu.2022.1028458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/20/2022] [Indexed: 12/15/2022] Open
Abstract
C-reactive protein (CRP) has been shown to be a potential candidate target in the immunotherapy of severe influenza A infection. However, it is unclear on the pathogenesis associated with CRP in influenza infections. Here, we used influenza A H1N1 CA04 to infect human CRP transgenic mice (KI), CRP knockout mice (KO), and wild-type mice (WT), respectively, and compared the viral pathogenicity and associated immune response in those mice. The results showed that CA04 infection resulted in 100%, 80%, and 60% death in KO, KI, and WT mice, respectively. Compared to WT mice, CA04 infection resulted in higher TCID50 in lungs on day 3 after infection but lowered HI antibody titers in sera of survivors on day 21 after infection in KI mice. ELISA assay showed that IFN-γ concentration was significantly increased in sera of WT, KI, or KO mice on day 7 after infection, and IL-17 was remarkably increased in sera of WT mice but decreased in sera of KI mice while no significant change in sera of KO mice on day 3 or 7 after infection. Quantitative RT-PCR showed that the relative expression levels of immune checkpoint CTLA-4, LAIR-1, GITR, BTLA, TIM-3, or PD-1 mRNA in the lung presented decreased levels on day 3 or 7 after infection in KI or KO mice. The correlation analysis showed that mRNA expression levels of the 6 molecules positively correlated with viral TICD50 in WT mice but negatively correlated with viral TCID50 in KI or KO mice. However, only LAIR-1 presented a significant correlation in each lung tissue of WT, KI, or KO mice with CA07 infection statistically. IHC results showed that LAIR-1 positive cells could be found in WT, KO, or KI mice lung tissues with CA04 infection, and the positive cells were mainly distributed in an inflammatory dense area. Our results suggested that deficiency of CRP or human CRP transgenic treatment aggravates influenza A virus infection in mice. CRP is a double sword in immune regulation of influenza infection in which IL-17 and immune checkpoint may be involved.
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Affiliation(s)
- Zhuohan Zhang
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yongjun Gao
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li Li
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Junhao Luo
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Rongbao Gao
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- National Health Commission of People's Republic of China (NHC) Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
- *Correspondence: Rongbao Gao,
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Torzewski M. C-Reactive Protein: Friend or Foe? Phylogeny From Heavy Metals to Modified Lipoproteins and SARS-CoV-2. Front Cardiovasc Med 2022; 9:797116. [PMID: 35402541 PMCID: PMC8987351 DOI: 10.3389/fcvm.2022.797116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/09/2022] [Indexed: 12/27/2022] Open
Abstract
Animal C-reactive protein (CRP) has a widespread existence throughout phylogeny implying that these proteins have essential functions mandatory to be preserved. About 500 million years of evolution teach us that there is a continuous interplay between emerging antigens and components of innate immunity. The most archaic physiological roles of CRP seem to be detoxication of heavy metals and other chemicals followed or accompanied by an acute phase response and host defense against bacterial, viral as well as parasitic infection. On the other hand, unusual antigens have emerged questioning the black-and-white perception of CRP as being invariably beneficial. Such antigens came along either as autoantigens like excessive tissue-stranded modified lipoprotein due to misdirected food intake linking CRP with atherosclerosis with an as yet open net effect, or as foreign antigens like SARS-CoV-2 inducing an uncontrolled CRP-mediated autoimmune response. The latter two examples impressingly demonstrate that a component of ancient immunity like CRP should not be considered under identical “beneficial” auspices throughout phylogeny but might effect quite the reverse as well.
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Temming AR, Tammes Buirs M, Bentlage AEH, Treffers LW, Feringa H, de Taeye SW, Kuijpers TW, Nagelkerke SQ, Brasser G, Mok JY, van Esch WJE, van den Berg TK, Rispens T, van der Schoot CE, Vidarsson G. C-Reactive Protein Enhances IgG-Mediated Cellular Destruction Through IgG-Fc Receptors in vitro. Front Immunol 2021; 12:594773. [PMID: 33790888 PMCID: PMC8006934 DOI: 10.3389/fimmu.2021.594773] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
Antibody-mediated blood disorders ensue after auto- or alloimmunization against blood cell antigens, resulting in cytopenia. Although the mechanisms of cell destruction are the same as in immunotherapies targeting tumor cells, many factors are still unknown. Antibody titers, for example, often do not strictly correlate with clinical outcome. Previously, we found C-reactive protein (CRP) levels to be elevated in thrombocytopenic patients, correlating with thrombocyte counts, and bleeding severity. Functionally, CRP amplified antibody-mediated phagocytosis of thrombocytes by phagocytes. To investigate whether CRP is a general enhancer of IgG-mediated target cell destruction, we extensively studied the effect of CRP on in vitro IgG-Fc receptor (FcγR)-mediated cell destruction: through respiratory burst, phagocytosis, and cellular cytotoxicity by a variety of effector cells. We now demonstrate that CRP also enhances IgG-mediated effector functions toward opsonized erythrocytes, in particular by activated neutrophils. We performed a first-of-a-kind profiling of CRP binding to all human FcγRs and IgA-Fc receptor I (FcαRI) using a surface plasmon resonance array. CRP bound these receptors with relative affinities of FcγRIa = FcγRIIa/b = FcγRIIIa > FcγRIIIb = FcαRI. Furthermore, FcγR blocking (in particular FcγRIa) abrogated CRP's ability to amplify IgG-mediated neutrophil effector functions toward opsonized erythrocytes. Finally, we observed that CRP also amplified killing of breast-cancer tumor cell line SKBR3 by neutrophils through anti-Her2 (trastuzumab). Altogether, we provide for the first time evidence for the involvement of specific CRP-FcγR interactions in the exacerbation of in vitro IgG-mediated cellular destruction; a trait that should be further evaluated as potential therapeutic target e.g., for tumor eradication.
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Affiliation(s)
- A. Robin Temming
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Matthias Tammes Buirs
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Arthur E. H. Bentlage
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Louise W. Treffers
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Hannah Feringa
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Steven W. de Taeye
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Taco W. Kuijpers
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Amsterdam University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Sietse Q. Nagelkerke
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Diseases, Amsterdam University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Giso Brasser
- Sanquin Reagents, Sanquin, Amsterdam, Netherlands
| | - Juk Yee Mok
- Sanquin Reagents, Sanquin, Amsterdam, Netherlands
| | | | - Timo K. van den Berg
- Sanquin Research and Landsteiner Laboratory, Department of Blood Cell Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Theo Rispens
- Sanquin Research and Landsteiner Laboratory, Department of Immunopathology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - C. Ellen van der Schoot
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Gestur Vidarsson
- Sanquin Research and Landsteiner Laboratory, Department of Experimental Immunohematology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
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Ngwa DN, Singh SK, Agrawal A. C-Reactive Protein-Based Strategy to Reduce Antibiotic Dosing for the Treatment of Pneumococcal Infection. Front Immunol 2021; 11:620784. [PMID: 33552084 PMCID: PMC7854908 DOI: 10.3389/fimmu.2020.620784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/03/2020] [Indexed: 11/13/2022] Open
Abstract
C-reactive protein (CRP) is a component of innate immunity. The concentration of CRP in serum increases in microbial infections including Streptococcus pneumoniae infection. Employing a mouse model of pneumococcal infection, it has been shown that passively administered human wild-type CRP protects mice against infection, provided that CRP is injected into mice within two hours of administering pneumococci. Engineered CRP (E-CRP) molecules have been reported recently; unlike wild-type CRP, passively administered E-CRP protected mice against infection even when E-CRP was injected into mice after twelve hours of administering pneumococci. The current study was aimed at comparing the protective capacity of E-CRP with that of an antibiotic clarithromycin. We established a mouse model of pneumococcal infection in which both E-CRP and clarithromycin, when used alone, provided minimal but equal protection against infection. In this model, the combination of E-CRP and clarithromycin drastically reduced bacteremia and increased survival of mice when compared to the protective effects of either E-CRP or clarithromycin alone. E-CRP was more effective in reducing bacteremia in mice treated with clarithromycin than in untreated mice. Also, there was 90% reduction in antibiotic dosing by including E-CRP in the antibiotic-treatment for maximal protection of infected mice. These findings provide an example of cooperation between the innate immune system and molecules that prevent multiplication of bacteria, and that should be exploited to develop novel combination therapies for infections against multidrug-resistant pneumococci. The reduction in antibiotic dosing by including E-CRP in the combination therapy might also resolve the problem of developing antibiotic resistance.
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Affiliation(s)
- Donald N Ngwa
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Sanjay K Singh
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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Ngwa DN, Singh SK, Gang TB, Agrawal A. Treatment of Pneumococcal Infection by Using Engineered Human C-Reactive Protein in a Mouse Model. Front Immunol 2020; 11:586669. [PMID: 33117400 PMCID: PMC7575696 DOI: 10.3389/fimmu.2020.586669] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/11/2020] [Indexed: 12/22/2022] Open
Abstract
C-reactive protein (CRP) binds to several species of bacterial pathogens including Streptococcus pneumoniae. Experiments in mice have revealed that one of the functions of CRP is to protect against pneumococcal infection by binding to pneumococci and activating the complement system. For protection, however, CRP must be injected into mice within a few hours of administering pneumococci, that is, CRP is protective against early-stage infection but not against late-stage infection. It is assumed that CRP cannot protect if pneumococci got time to recruit complement inhibitor factor H on their surface to become complement attack-resistant. Since the conformation of CRP is altered under inflammatory conditions and altered CRP binds to immobilized factor H also, we hypothesized that in order to protect against late-stage infection, CRP needed to change its structure and that was not happening in mice. Accordingly, we engineered CRP molecules (E-CRP) which bind to factor H on pneumococci but do not bind to factor H on any host cell in the blood. We found that E-CRP, in cooperation with wild-type CRP, was protective regardless of the timing of administering E-CRP into mice. We conclude that CRP acts via two different conformations to execute its anti-pneumococcal function and a model for the mechanism of action of CRP is proposed. These results suggest that pre-modified CRP, such as E-CRP, is therapeutically beneficial to decrease bacteremia in pneumococcal infection. Our findings may also have implications for infections with antibiotic-resistant pneumococcal strains and for infections with other bacterial species that use host proteins to evade complement-mediated killing.
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Affiliation(s)
- Donald N Ngwa
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Sanjay K Singh
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Toh B Gang
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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Singh SK, Ngwa DN, Agrawal A. Complement Activation by C-Reactive Protein Is Critical for Protection of Mice Against Pneumococcal Infection. Front Immunol 2020; 11:1812. [PMID: 32903624 PMCID: PMC7438579 DOI: 10.3389/fimmu.2020.01812] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/07/2020] [Indexed: 01/23/2023] Open
Abstract
C-reactive protein (CRP), a component of the innate immune system, is an antipneumococcal plasma protein. Human CRP has been shown to protect mice against infection with lethal doses of Streptococcus pneumoniae by decreasing bacteremia. in vitro, CRP binds to phosphocholine-containing substances, such as pneumococcal C-polysaccharide, in a Ca2+-dependent manner. Phosphocholine-complexed human CRP activates the complement system in both human and murine sera. The mechanism of antipneumococcal action of CRP in vivo, however, has not been defined yet. In this study, we tested a decades-old hypothesis that the complement-activating property of phosphocholine-complexed CRP contributes to protection of mice against pneumococcal infection. Our approach was to investigate a CRP mutant, incapable of activating murine complement, in mouse protection experiments. We employed site-directed mutagenesis of CRP, guided by its three-dimensional structure, and identified a mutant H38R which, unlike wild-type CRP, did not activate complement in murine serum. Substitution of His38 with Arg in CRP did not affect the pentameric structure of CRP, did not affect the binding of CRP to pneumococci, and did not decrease the stability of CRP in mouse circulation. Employing a murine model of pneumococcal infection, we found that passively administered H38R CRP failed to protect mice against infection. Infected mice injected with H38R CRP showed no reduction in bacteremia and did not survive longer, as opposed to infected mice treated with wild-type CRP. Thus, the hypothesis that complement activation by phosphocholine-complexed CRP is an antipneumococcal effector function was supported. We can conclude now that complement activation by phosphocholine-complexed CRP is indeed essential for CRP-mediated protection of mice against pneumococcal infection.
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Affiliation(s)
- Sanjay K Singh
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Donald N Ngwa
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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Abstract
The immune system is central to our interactions with the world in which we live and importantly dictates our response to potential allergens, toxins, and pathogens to which we are constantly exposed. Understanding the mechanisms that underlie protective host immune responses against microbial pathogens is vital for the development of improved treatment and vaccination strategies against infections. To that end, inherited immunodeficiencies that manifest with susceptibility to bacterial, viral, and/or fungal infections have provided fundamental insights into the indispensable contribution of key immune pathways in host defense against various pathogens. In this mini-review, we summarize the findings from a series of recent publications in which inherited immunodeficiencies have helped illuminate the interplay of human immunity and resistance to infection.
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Affiliation(s)
- Gregory M Constantine
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, 20814, USA
| | - Michail S Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, 20814, USA
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15
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Li Q, Wang Q, Xu W, Ma Y, Wang Q, Eatman D, You S, Zou J, Champion J, Zhao L, Cui Y, Li W, Deng Y, Ma L, Wu B, Wang G, Zhang X, Wang Q, Bayorh MA, Song Q. C-Reactive Protein Causes Adult-Onset Obesity Through Chronic Inflammatory Mechanism. Front Cell Dev Biol 2020; 8:18. [PMID: 32154244 PMCID: PMC7044181 DOI: 10.3389/fcell.2020.00018] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/10/2020] [Indexed: 01/04/2023] Open
Abstract
Obesity is characterized by low-grade chronic inflammation. As an acute-phase reactant to inflammation and infection, C-reactive protein (CRP) has been found to be the strongest factor associated with obesity. Here we show that chronic elevation of human CRP at baseline level causes the obesity. The obesity phenotype is confirmed by whole-body magnetic resonance imaging (MRI), in which the total fat mass is 6- to 9- fold higher in the CRP rats than the control rats. Univariate linear regression analysis showed different growth rates between the CRP rats and the control rats, and that the difference appears around 11 weeks old, indicating that they developed adult-onset obesity. We also found that chronic elevation of CRP can prime molecular changes broadly in the innate immune system, energy expenditure systems, thyroid hormones, apolipoproteins, and gut flora. Our data established a causal role of CRP elevation in the development of adult-onset obesity.
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Affiliation(s)
- Qiling Li
- Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China.,Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Qi Wang
- Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Wei Xu
- Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Yamin Ma
- Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Qing Wang
- Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Danita Eatman
- Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Shaojin You
- Histo-Pathology Core, Atlanta Research & Educational Foundation, Atlanta VA Medical Center, Decatur, GA, United States
| | - Jin Zou
- Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, United States
| | - James Champion
- Center for Laboratory Animal Resources, Morehouse School of Medicine, Atlanta, GA, United States
| | - Lanbo Zhao
- Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China
| | - Ye Cui
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, United States
| | - Wenzhi Li
- Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Yangyang Deng
- Institute of Artificial Intelligence and Robotics, Xi'an Jiaotong University, Xi'an, China
| | - Li Ma
- Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Biao Wu
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, China
| | - Guangdi Wang
- Department of Chemistry, Xavier University of Louisiana, New Orleans, LA, United States
| | - Xiaodong Zhang
- Yerkes Imaging Center MRI Core, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States
| | - Qingwei Wang
- Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
| | - Mohamed A Bayorh
- Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Qing Song
- Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China.,Cardiovascular Research Institute and Department of Medicine, Morehouse School of Medicine, Atlanta, GA, United States
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A reporter mouse for non-invasive detection of toll-like receptor ligands induced acute phase responses. Sci Rep 2019; 9:19065. [PMID: 31836734 PMCID: PMC6910947 DOI: 10.1038/s41598-019-55281-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/26/2019] [Indexed: 12/02/2022] Open
Abstract
The acute phase response (APR) is a systemic first-line defense against challenges including infection, trauma, stress, and neoplasia. Alteration of acute phase protein (APP) levels in plasma is the most important change during acute phase response. C-reactive protein (CRP), which increases dramatically during inflammation onset, is an indicator of inflammation. To monitor the process of APR, we generated human CRP promoter-driven luciferase transgenic (hCRP-Luc) mice to quantify the hCRP promoter activation in vivo. The naïve female hCRP-Luc mice express low basal levels of liver bioluminescence, but the naïve male hCRP-Luc mice do not. Thus, female hCRP-Luc mice are suitable for monitoring the process of APR. The liver bioluminescence of female hCRP-Luc mice can be induced by several toll-like receptor (TLR) ligands. The expression of liver bioluminescence was highly sensitive to endotoxin stimulation in a dose-dependent manner. On-off-on bioluminescence response was noted in female hCRP-Luc mice upon two endotoxin stimulations one month apart. The LPS-induced bioluminescence of the female hCRP-Luc mice was IL-6-mediated and associated with APP alpha-1-acid glycoprotein expression. In conclusion, the female hCRP-Luc mouse is a non-invasive, sensitive and reusable reporter tool for APR.
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Abstract
C-reactive protein (CRP) is an evolutionarily conserved protein. From arthropods to humans, CRP has been found in every organism where the presence of CRP has been sought. Human CRP is a pentamer made up of five identical subunits which binds to phosphocholine (PCh) in a Ca2+-dependent manner. In various species, we define a protein as CRP if it has any two of the following three characteristics: First, it is a cyclic oligomer of almost identical subunits of molecular weight 20–30 kDa. Second, it binds to PCh in a Ca2+-dependent manner. Third, it exhibits immunological cross-reactivity with human CRP. In the arthropod horseshoe crab, CRP is a constitutively expressed protein, while in humans, CRP is an acute phase plasma protein and a component of the acute phase response. As the nature of CRP gene expression evolved from a constitutively expressed protein in arthropods to an acute phase protein in humans, the definition of CRP became distinctive. In humans, CRP can be distinguished from other homologous proteins such as serum amyloid P, but this is not the case for most other vertebrates and invertebrates. Literature indicates that the binding ability of CRP to PCh is less relevant than its binding to other ligands. Human CRP displays structure-based ligand-binding specificities, but it is not known if that is true for invertebrate CRP. During evolution, changes in the intrachain disulfide and interchain disulfide bonds and changes in the glycosylation status of CRP may be responsible for different structure-function relationships of CRP in various species. More studies of invertebrate CRP are needed to understand the reasons behind such evolution of CRP. Also, CRP evolved as a component of and along with the development of the immune system. It is important to understand the biology of ancient CRP molecules because the knowledge could be useful for immunodeficient individuals.
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Affiliation(s)
- Asmita Pathak
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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18
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Ngwa DN, Agrawal A. Structure-Function Relationships of C-Reactive Protein in Bacterial Infection. Front Immunol 2019; 10:166. [PMID: 30863393 PMCID: PMC6400226 DOI: 10.3389/fimmu.2019.00166] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 01/18/2019] [Indexed: 12/26/2022] Open
Abstract
One host defense function of C-reactive protein (CRP) is to protect against Streptococcus pneumoniae infection as shown by experiments employing murine models of pneumococcal infection. The protective effect of CRP is due to reduction in bacteremia. There is a distinct relationship between the structure of CRP and its anti-pneumococcal function. CRP is functional in both native and non-native pentameric structural conformations. In the native conformation, CRP binds to pneumococci through the phosphocholine molecules present on the C-polysaccharide of the pneumococcus and the anti-pneumococcal function probably involves the known ability of ligand-complexed CRP to activate the complement system. In the native structure-function relationship, CRP is protective only when given to mice within a few hours of the administration of pneumococci. The non-native pentameric conformation of CRP is created when CRP is exposed to conditions mimicking inflammatory microenvironments, such as acidic pH and redox conditions. In the non-native conformation, CRP binds to immobilized complement inhibitor factor H in addition to being able to bind to phosphocholine. Recent data using CRP mutants suggest that the factor H-binding function of non-native CRP is beneficial: in the non-native structure-function relationship, CRP can be given to mice any time after the administration of pneumococci irrespective of whether the pneumococci became complement-resistant or not. In conclusion, while native CRP is protective only against early stage infection, non-native CRP is protective against both early stage and late stage infections. Because non-native CRP displays phosphocholine-independent anti-pneumococcal activity, it is quite possible that CRP functions as a general anti-bacterial molecule.
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Affiliation(s)
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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19
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Abstract
Pneumonia is a type of acute lower respiratory infection that is common and severe. The outcome of lower respiratory infection is determined by the degrees to which immunity is protective and inflammation is damaging. Intercellular and interorgan signaling networks coordinate these actions to fight infection and protect the tissue. Cells residing in the lung initiate and steer these responses, with additional immunity effectors recruited from the bloodstream. Responses of extrapulmonary tissues, including the liver, bone marrow, and others, are essential to resistance and resilience. Responses in the lung and extrapulmonary organs can also be counterproductive and drive acute and chronic comorbidities after respiratory infection. This review discusses cell-specific and organ-specific roles in the integrated physiological response to acute lung infection, and the mechanisms by which intercellular and interorgan signaling contribute to host defense and healthy respiratory physiology or to acute lung injury, chronic pulmonary disease, and adverse extrapulmonary sequelae. Pneumonia should no longer be perceived as simply an acute infection of the lung. Pneumonia susceptibility reflects ongoing and poorly understood chronic conditions, and pneumonia results in diverse and often persistent deleterious consequences for multiple physiological systems.
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Affiliation(s)
- Lee J Quinton
- Pulmonary Center, Boston University School of Medicine , Boston, Massachusetts
| | - Allan J Walkey
- Pulmonary Center, Boston University School of Medicine , Boston, Massachusetts
| | - Joseph P Mizgerd
- Pulmonary Center, Boston University School of Medicine , Boston, Massachusetts
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20
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Abstract
The phylogenetically ancient, pentraxin family of plasma proteins, comprises C-reactive protein (CRP) and serum amyloid P component (SAP) in humans and the homologous proteins in other species. They are composed of five, identical, non-covalently associated protomers arranged with cyclic pentameric symmetry in a disc-like configuration. Each protomer has a calcium dependent site that mediates the particular specific ligand binding responsible for all the rigorously established functional properties of these proteins. No genetic deficiency of either human CRP or SAP has been reported, nor even any sequence polymorphism in the proteins themselves. Although their actual functions in humans are therefore unknown, gene deletion studies in mice demonstrate that both proteins can contribute to innate immunity. CRP is the classical human acute phase protein, routinely measured in clinical practice worldwide to monitor disease activity. Human SAP, which is not an acute phase protein, is a universal constituent of all human amyloid deposits as a result of its avid specific binding to amyloid fibrils of all types. SAP thereby contributes to amyloid formation and persistence in vivo. Whole body radiolabelled SAP scintigraphy safely and non-invasively localizes and quantifies systemic amyloid deposits, and has transformed understanding of the natural history of amyloidosis and its response to treatment. Human SAP is also a therapeutic target, both in amyloidosis and Alzheimer's disease. Our drug, miridesap, depletes SAP from the blood and the brain and is currently being tested in the DESPIAD clinical trial in Alzheimer's disease. Meanwhile, the obligate therapeutic partnership of miridesap, to deplete circulating SAP, and dezamizumab, a humanized monoclonal anti-SAP antibody that targets residual SAP in amyloid deposits, produces unprecedented removal of amyloid from the tissues and improves organ function. Human CRP binds to dead and damaged cells in vivo and activates complement and this can exacerbate pre-existing tissue damage. The adverse effects of CRP are completely abrogated by compounds that block its binding to autologous ligands and we are developing CRP inhibitor drugs. The present personal and critical perspective on the pentraxins reports, for the first time, the key role of serendipity in our work since 1975. (345 words).
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Affiliation(s)
- Mark. B. Pepys
- Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, University College London, London, United Kingdom
- National Institute for Health Research University College London Hospitals Biomedical Research Centre, London, United Kingdom
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Koh SH, Shin SG, Andrade MJ, Go RH, Park S, Woo CH, Lim JH. Long pentraxin PTX3 mediates acute inflammatory responses against pneumococcal infection. Biochem Biophys Res Commun 2017; 493:671-676. [PMID: 28864415 DOI: 10.1016/j.bbrc.2017.08.133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 08/29/2017] [Indexed: 01/01/2023]
Abstract
Streptococcus pneumoniae is an important human pathogen responsible for more than 2 million deaths annually worldwide. The airway epithelium acts as the first-line of defense against pneumococcal infections by regulating acute inflammation against invading pneumococcus. Despite the intact adaptive immunity, failure in early defense due to loss of pattern recognition receptors (PRRs) and/or acute phase proteins (APPs) results in detrimental damage and death. C-reactive protein (CRP), the first found APP, is a member of the pentraxin family of proteins and an important soluble PRR for pneumococcus. CRP and another short pentraxin, serum amyloid P, are critical for acute defense against pneumococcal infection. However, the role of the long pentraxin PTX3 in regulating pneumococcal infections is unknown. In this study, PTX3 expression was upregulated by pneumococcus in epithelial cells and in lungs of mice. In addition, PTX3 potentiated pneumococcal inflammation; overexpression of PTX3 enhanced pneumococcus-induced cytokine expression, whereas knock-down of PTX3 with siPTX3 inhibited the cytokine expression. Furthermore, PTX3 deficiency indeed ameliorated acute inflammation and protected mice against death following pneumococcal infection. Pneumococcal toxin pneumolysin was responsible for PTX3 expression and upregulated PTX3 expression via JNK MAPK signaling. These data implicate PTX3 as a novel therapeutic target for the control of acute inflammation by pneumococcus.
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Affiliation(s)
- Seo Hyun Koh
- Department of Microbiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea
| | - Seul Gi Shin
- Department of Microbiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea
| | - Maria Jose Andrade
- Department of Microbiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea
| | - Ryun-Hee Go
- Department of Microbiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea
| | - Seonghee Park
- Department of Physiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea
| | - Chang-Hoon Woo
- Department of Pharmacology and Smart-Aging Convergence Research Center, Yeungnam University College of Medicine, 170 Hyeonchung-ro, Nam-gu, Daegu 42415, Republic of Korea.
| | - Jae Hyang Lim
- Department of Microbiology, College of Medicine, Ewha Womans University, 1071 Anyangcheon-ro, Yangcheon-gu, Seoul 07985, Republic of Korea.
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22
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Abstract
What is inflammation's big idea? In this brief overview of the role of myeloid cells in inflammation, we will critically discuss what drives the initiation, amplification, and resolution of inflammation in different anatomical sites in response to different pathological stimuli. It can be argued that we have a good understanding of the basic principles that underlie myeloid cell activation and the mobilization of innate immune cells to sites of injury and infection in acute inflammation. The challenge now for inflammation biologists is to understand how resolution of this normal physiological response goes wrong in hyperacute and chronic inflammation. A better understanding of how inflammation is regulated will allow us to develop new anti-inflammatory drugs that will reduce the burden of inflammatory disease without compromising the patient's immune defenses against infectious disease. Ideally such drugs should encourage a return to homeostasis and enhance tissue repair processes.
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24
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The role of IL-6 in host defence against infections: immunobiology and clinical implications. Nat Rev Rheumatol 2017; 13:399-409. [DOI: 10.1038/nrrheum.2017.83] [Citation(s) in RCA: 270] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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25
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Josefina Venero‐Fernández S, Fundora‐Hernández H, Batista‐Gutierrez L, Suárez‐Medina R, de la C. Mora‐Faife E, García‐García G, del Valle‐Infante I, Gómez‐Marrero L, Britton J, Fogarty AW. The association of low birth weight with serum C reactive protein in 3-year-old children living in Cuba: A population-based prospective study. Am J Hum Biol 2017; 29:e22936. [PMID: 27859847 PMCID: PMC5484324 DOI: 10.1002/ajhb.22936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/18/2016] [Accepted: 10/08/2016] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE Low birthweight is associated with a decreased risk of childhood leukemia and an increased risk of both cardiovascular disease and all-cause mortality in adult life. Possible biological mediators include systemic innate immunity and inflammation. We tested the hypothesis that birthweight was inversely associated with serum high sensitivity C reactive protein assay (hsCRP), a measure of both innate immunity and systemic inflammation. METHODS Data on birthweight and current anthropometric measures along with a range of exposures were collected at 1 and 3 years of age in a population-based cohort study of young children living in Havana, Cuba. A total of 986 children aged 3-years-old provided blood samples that were analyzed for serum hsCRP levels. RESULTS Nearly 49% of children had detectable hsCRP levels in their serum. Lower birthweight was linearly associated with the natural log of hsCRP levels (beta coefficient -0.70 mg L-1 per kg increase in birthweight, 95% CI: -1.34 to -0.06). This was attenuated but still present after adjustment for the child's sex and municipality (-0.65 mg L-1 per kg birthweight; 95% CI: -1.38 to +0.08). There were no associations between growth from birth or anthropometric measures at 3 years and systemic inflammation. CONCLUSIONS Birthweight was inversely associated with serum hsCRP levels in children aged 3 years living in Cuba. These observations provide a potential mechanism that is present at the age of 3 years to explain the association between low birthweight and both decreased childhood leukemia and increased cardiovascular disease in adults.
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Affiliation(s)
| | - Hermes Fundora‐Hernández
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Lourdes Batista‐Gutierrez
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Ramón Suárez‐Medina
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Esperanza de la C. Mora‐Faife
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Gladys García‐García
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Ileana del Valle‐Infante
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - Liem Gómez‐Marrero
- Instituto Nacional de Higiene, Epidemiología y MicrobiologíaInfanta No 1158 e/ Llinás y ClavelCódigo Postal 10300La HabanaCuba
| | - John Britton
- Nottingham Biomedical Research Unit, Division of Epidemiology and Public HealthUniversity of Nottingham, Clinical Sciences Building, City HospitalNottinghamNG5 1PBUnited Kingdom
| | - Andrew W. Fogarty
- Nottingham Biomedical Research Unit, Division of Epidemiology and Public HealthUniversity of Nottingham, Clinical Sciences Building, City HospitalNottinghamNG5 1PBUnited Kingdom
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Singh SK, Thirumalai A, Pathak A, Ngwa DN, Agrawal A. Functional Transformation of C-reactive Protein by Hydrogen Peroxide. J Biol Chem 2017; 292:3129-3136. [PMID: 28096464 PMCID: PMC5336149 DOI: 10.1074/jbc.m116.773176] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/11/2017] [Indexed: 12/21/2022] Open
Abstract
C-reactive protein (CRP) is present at sites of inflammation including amyloid plaques, atherosclerotic lesions, and arthritic joints. CRP, in its native pentameric structural conformation, binds to cells and molecules that have exposed phosphocholine (PCh) groups. CRP, in its non-native pentameric structural conformation, binds to a variety of deposited, denatured, and aggregated proteins, in addition to binding to PCh-containing substances. In this study, we investigated the effects of H2O2, a prototypical reactive oxygen species that is also present at sites of inflammation, on the ligand recognition function of CRP. Controlled H2O2 treatment of native CRP did not monomerize CRP and did not affect the PCh binding activity of CRP. In solid phase ELISA-based ligand binding assays, purified pentameric H2O2-treated CRP bound to a number of immobilized proteins including oxidized LDL, IgG, amyloid β peptide 1-42, C4b-binding protein, and factor H, in a CRP concentration- and ligand concentration-dependent manner. Using oxidized LDL as a representative protein ligand for H2O2-treated CRP, we found that the binding occurred in a Ca2+-independent manner and did not involve the PCh-binding site of CRP. We conclude that H2O2 is a biological modifier of the structure and ligand recognition function of CRP. Overall, the data suggest that the ligand recognition function of CRP is dependent on the presence of an inflammatory microenvironment. We hypothesize that one of the functions of CRP at sites of inflammation is to sense the inflammatory microenvironment, change its own structure in response but remain pentameric, and then bind to pathogenic proteins deposited at those sites.
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Affiliation(s)
- Sanjay K Singh
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Avinash Thirumalai
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Asmita Pathak
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Donald N Ngwa
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614.
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Thirumalai A, Singh SK, Hammond DJ, Gang TB, Ngwa DN, Pathak A, Agrawal A. Purification of recombinant C-reactive protein mutants. J Immunol Methods 2017; 443:26-32. [PMID: 28167277 DOI: 10.1016/j.jim.2017.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/09/2017] [Accepted: 01/17/2017] [Indexed: 12/18/2022]
Abstract
C-reactive protein (CRP) is an evolutionarily conserved protein, a component of the innate immune system, and an acute phase protein in humans. In addition to its raised level in blood in inflammatory states, CRP is also localized at sites of inflammation including atherosclerotic lesions, arthritic joints and amyloid plaque deposits. Results of in vivo experiments in animal models of inflammatory diseases indicate that CRP is an anti-pneumococcal, anti-atherosclerotic, anti-arthritic and an anti-amyloidogenic molecule. The mechanisms through which CRP functions in inflammatory diseases are not fully defined; however, the ligand recognition function of CRP in its native and non-native pentameric structural conformations and the complement-activating ability of ligand-complexed CRP have been suggested to play a role. One tool to understand the structure-function relationships of CRP and determine the contributions of the recognition and effector functions of CRP in host defense is to employ site-directed mutagenesis to create mutants for experimentation. For example, CRP mutants incapable of binding to phosphocholine are generated to investigate the importance of the phosphocholine-binding property of CRP in mediating host defense. Recombinant CRP mutants can be expressed in mammalian cells and, if expressed, can be purified from the cell culture media. While the methods to purify wild-type CRP are well established, different purification strategies are needed to purify various mutant forms of CRP if the mutant does not bind to either calcium or phosphocholine. In this article, we report the methods used to purify pentameric recombinant wild-type and mutant CRP expressed in and secreted by mammalian cells.
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Affiliation(s)
- Avinash Thirumalai
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Sanjay K Singh
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - David J Hammond
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Toh B Gang
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Donald N Ngwa
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Asmita Pathak
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Alok Agrawal
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States.
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Ovnat Tamir S, Roth Y, Goldfarb A, Grotto I, Marom T. Severity of pneumococcal versus non-pneumococcal acute otitis media in children. Clin Otolaryngol 2016; 40:370-7. [PMID: 25644105 DOI: 10.1111/coa.12384] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Pneumococcal acute otitis media (AOM) has been previously considered as a more severe disease than that caused by other otopathogens, based on clinical and/or otologic scores. We sought to test this hypothesis in the pneumococcal conjugated vaccine (PCV) era. METHODS Children <6 years who presented with 'severe' AOM episodes with middle ear fluid (MEF) cultures during 2008-2013 were retrospectively identified. 'Severe' AOM episodes were considered if tympanocentesis was required or if spontaneous otorrhea was present. Data were extracted for demographics, clinical and laboratory tests. Children were categorised according to their PCV status as 'unimmunised' or 'PCV7/PCV13 immunised' and according to their MEF culture results into the 'pneumococcal' or the 'non-pneumococcal' group. Leukocytosis was defined as white blood cells (WBC) count >15 000/μL, and elevated C-reactive protein (CRP) level was considered as >50 mg/L. RESULTS Of 295 eligible AOM episodes, 106 (36%) were culture positive. Children in the pneumococcal group (65, 61%) had a significantly higher WBC counts and higher CRP levels, were more often <2 years old and were more prone to complicate with acute mastoiditis (AM), compared to children in the non-pneumococcal group, P = 0.03, P = 0.02, P = 0.04 and P = 0.03, respectively. In the pneumococcal group, unimmunised children had higher WBC counts when compared with PCV13-immunised children (P = 0.04), but there were no appreciable differences in CRP levels between unimmunised and PCV7/PCV13-immunised children. CONCLUSION Pneumococcal AOM is associated with higher leukocytosis and CRP levels than non-pneumococcal AOM. Circulating Streptococcus pneumoniae strains causing 'severe' AOM in PCV13-immunised children yielded lower inflammatory responses when compared with unimmunised children.
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Affiliation(s)
- S Ovnat Tamir
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Tel Aviv University Sackler Faculty of Medicine, Holon, Israel
| | - Y Roth
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Tel Aviv University Sackler Faculty of Medicine, Holon, Israel
| | - A Goldfarb
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Tel Aviv University Sackler Faculty of Medicine, Holon, Israel
| | - I Grotto
- Public Health Services, Israel Ministry of Health, Jerusalem, Israel.,Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - T Marom
- Department of Otolaryngology-Head and Neck Surgery, Edith Wolfson Medical Center, Tel Aviv University Sackler Faculty of Medicine, Holon, Israel
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Ahmed UK, Maller NC, Iqbal AJ, Al-Riyami L, Harnett W, Raynes JG. The Carbohydrate-linked Phosphorylcholine of the Parasitic Nematode Product ES-62 Modulates Complement Activation. J Biol Chem 2016; 291:11939-53. [PMID: 27044740 PMCID: PMC4882459 DOI: 10.1074/jbc.m115.702746] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 12/04/2022] Open
Abstract
Parasitic nematodes manufacture various carbohydrate-linked phosphorylcholine (PCh)-containing molecules, including ES-62, a protein with an N-linked glycan terminally substituted with PCh. The PCh component is biologically important because it is required for immunomodulatory effects. We showed that most ES-62 was bound to a single protein, C-reactive protein (CRP), in normal human serum, displaying a calcium-dependent, high-avidity interaction and ability to form large complexes. Unexpectedly, CRP binding to ES-62 failed to efficiently activate complement as far as the C3 convertase stage in comparison with PCh-BSA and PCh-containing Streptococcus pneumoniae cell wall polysaccharide. C1q capture assays demonstrated an ES-62-CRP-C1q interaction in serum. The three ligands all activated C1 and generated C4b to similar extents. However, a C2a active site was not generated following ES-62 binding to CRP, demonstrating that C2 cleavage was far less efficient for ES-62-containing complexes. We proposed that failure of C2 cleavage was due to the flexible nature of carbohydrate-bound PCh and that reduced proximity of the C1 complex was the reason that C2 was poorly cleaved. This was confirmed using synthetic analogues that were similar to ES-62 only in respect of having a flexible PCh. Furthermore, ES-62 was shown to deplete early complement components, such as the rate-limiting C4, following CRP interaction and thereby inhibit classical pathway activation. Thus, flexible PCh-glycan represents a novel mechanism for subversion of complement activation. These data illustrate the importance of the rate-limiting C4/C2 stage of complement activation and reveal a new addition to the repertoire of ES-62 immunomodulatory mechanisms with possible therapeutic applications.
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Affiliation(s)
- Umul Kulthum Ahmed
- From the Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT and
| | - N Claire Maller
- From the Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT and
| | - Asif J Iqbal
- From the Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT and
| | - Lamyaa Al-Riyami
- the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - William Harnett
- the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - John G Raynes
- From the Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT and
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Gliddon T, Salman S, Robinson JO, Manning L. Modeling C-reactive protein kinetic profiles for use as a clinical prediction tool in patients with Staphylococcus aureus bacteremia. Biomark Med 2015; 9:947-55. [DOI: 10.2217/bmm.15.73] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: We hypothesized that C-reactive protein (CRP) kinetics can be accurately modeled and might have clinical utility in a cohort of patients with Staphylococcus aureus bacteremia. Materials & methods: We constructed and validated a nonlinear mixed effects model using CRP values obtained during the first week of illness. Results: Hematological malignancy, prosthetic heart valves and metastatic seeding were identified as major covariates that influenced CRP kinetics. When considering the presence of metastatic infection as an ‘unknown’, the model could predict its presence through analysis of the observed CRP profile with an Area-under-the-Receiver-Operator-Characteristic curve of 0.81, indicating some diagnostic accuracy. Conclusion: We conclude that early CRP kinetics can be accurately modeled and can help identify patients with metastatic seeding in S. aureus bacteremia. Further validation is required.
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Affiliation(s)
- Thomas Gliddon
- Pathwest Laboratory Medicine, Nedlands, WA, Australia
- Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - Sam Salman
- Sir Charles Gairdner Hospital, Nedlands, WA, Australia
- Harry Perkins Research Institute, School of Medicine & Pharmacology, University of Western Australia, Fiona Stanley Hospital, Western Australia, University of Western Australia, WA, Australia
| | - James Owen Robinson
- Pathwest Laboratory Medicine, Nedlands, WA, Australia
- Australian Collaborating Centre for Enterococcus & Staphylococcus Species (ACCESS) Typing & Research, School of Veterinary & Life Sciences, Murdoch University & School of Biomedical Sciences, Curtin University, Perth, WA, Australia
- Royal Perth Hospital, Perth, WA, Australia
- Fiona Stanley Hospital, Murdoch, WA, Australia
| | - Laurens Manning
- Harry Perkins Research Institute, School of Medicine & Pharmacology, University of Western Australia, Fiona Stanley Hospital, Western Australia, University of Western Australia, WA, Australia
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C-reactive protein protects mice against pneumococcal infection via both phosphocholine-dependent and phosphocholine-independent mechanisms. Infect Immun 2015; 83:1845-52. [PMID: 25690104 DOI: 10.1128/iai.03058-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/12/2015] [Indexed: 01/28/2023] Open
Abstract
The mechanism of action of C-reactive protein (CRP) in protecting mice against lethal Streptococcus pneumoniae infection is unknown. The involvement of the phosphocholine (PCh)-binding property of CRP in its antipneumococcal function previously has been explored twice, with conflicting results. In this study, using three different intravenous sepsis mouse models, we investigated the role of the PCh-binding property of CRP by employing a CRP mutant incapable of binding to PCh. The ability of wild-type CRP to protect mice against infection was found to differ in the three models; the protective ability of wild-type CRP decreased when the severity of infection was increased, as determined by measuring mortality and bacteremia. In the first animal model, in which we used 25 μg of CRP and 10(7) CFU of pneumococci, both wild-type and mutant CRP protected mice against infection, suggesting that the protection was independent of the PCh-binding activity of CRP. In the second model, in which we used 25 μg of CRP and 5 × 10(7) CFU of pneumococci, mutant CRP was not protective while wild-type CRP was, suggesting that the protection was dependent on the PCh-binding activity of CRP. In the third model, in which we used 150 μg of CRP and 10(7) CFU of pneumococci, mutant CRP was as protective as wild-type CRP, again indicating that the protection was independent of the PCh-binding activity of CRP. We conclude that both PCh-dependent and PCh-independent mechanisms are involved in the CRP-mediated decrease in bacteremia and the resulting protection of mice against pneumococcal infection.
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Pryce JW, Bamber AR, Ashworth MT, Klein NJ, Sebire NJ. Immunohistochemical expression of inflammatory markers in sudden infant death; ancillary tests for identification of infection. J Clin Pathol 2014; 67:1044-51. [DOI: 10.1136/jclinpath-2014-202489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
AimsSudden unexpected death in infancy (SUDI) investigation requires extensive ancillary investigations, the results of which, such as postmortem microbiology, can be difficult to interpret. Markers of an inflammatory response, including interleukin 6 (IL-6), c-reactive protein (CRP) and cellular adhesion molecules are elevated in infections, yet little attention has been paid to their assessment after death. This study investigates the role of inflammatory markers in SUDI autopsies for determining cause of death.MethodsCases of SUDI over a 14 year period were identified from an autopsy database and 100 cases were selected for immunohistochemical staining of heart and liver for IL-6, CRP, P-selectin, VCAM-1 and ICAM-1 (CD54), with staining patterns compared between five groups, including infectious and unexplained SUDI.ResultsThere were significant differences between groups. Cases of histological infection demonstrated strongly positive hepatocyte CRP and ICAM-1 expression and increased myocardial staining for CRP. Half of trauma-related deaths demonstrated diffuse hepatic CRP expression but without myocardial CRP staining. Staining of unexplained SUDI cases were predominantly negative, apart from a subgroup in whom Escherichia Coli was identified, who had increased expression of hepatic IL-6.ConclusionsThere were distinct patterns of organ-specific CRP and ICAM-1 expression in SUDI by cause of death. These markers of inflammation were rarely present in unexplained SUDI suggesting either a non-inflammatory cause of death or a failure to mount an effective acute phase response. Immunohistochemical staining offers potential to identify infection-related deaths and provides insight into SUDI mechanisms.
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Thirumalai A, Singh SK, Hammond DJ, Gang TB, Ngwa DN, Pathak A, Agrawal A. Probing the phosphocholine-binding site of human C-reactive protein by site-directed mutagenesis. J Biol Chem 1992; 267:25353-8. [PMID: 1460031 PMCID: PMC5317095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human C-reactive protein (CRP) can activate the classical pathway of complement and function as an opsonin only when it is complexed to an appropriate ligand. Most known CRP ligands bind to the phosphocholine (PCh)-binding site of the protein. In the present study, we used oligonucleotide-directed site-specific mutagenesis to investigate structural determinants of the PCh-binding site of CRP. Eight mutant recombinant (r) CRP, Y40F; E42Q; Y40F, E42Q; K57Q; R58G; K57Q, R58G; W67K; and K57Q, R58G, W67K were constructed and expressed in COS cells. Wild-type and all mutant rCRP except for the W67K mutants bound to solid-phase PCh-substituted bovine serum albumin (PCh-BSA) with similar apparent avidities. However, W67K rCRP had decreased avidity for PCh-BSA and the triple mutant, K57Q, R58G, W67K, failed to bind PCh-BSA. Inhibition experiments using PCh and dAMP as inhibitors indicated that both Lys-57 and Arg-58 contribute to PCh binding. They also indicated that Trp-67 provides interactions with the choline group. The Y40F and E42Q mutants were found to have increased avidity for fibronectin compared to wild-type rCRP. We conclude that the residues Lys-57, Arg-58, and Trp-67 contribute to the structure of the PCh-binding site of human CRP. Residues Tyr-40 and Glu-42 do not appear to participate in the formation of the PCh-binding site of CRP, however, they may be located in the vicinity of the fibronectin-binding site of CRP.
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Affiliation(s)
| | | | | | | | | | | | - Alok Agrawal
- Corresponding author at: Department of Biomedical Sciences, Quillen College of Medicine, P. O. Box 70577, East Tennessee State University, Johnson City, TN 37614, USA, Tel.: +1 423 439 6336; fax: +1 423 439 8044,
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