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Hensler E, Petros H, Gray CC, Chung CS, Ayala A, Fallon EA. The Neonatal Innate Immune Response to Sepsis: Checkpoint Proteins as Novel Mediators of This Response and as Possible Therapeutic/Diagnostic Levers. Front Immunol 2022; 13:940930. [PMID: 35860251 PMCID: PMC9289477 DOI: 10.3389/fimmu.2022.940930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/07/2022] [Indexed: 11/23/2022] Open
Abstract
Sepsis, a dysfunctional immune response to infection leading to life-threatening organ injury, represents a significant global health issue. Neonatal sepsis is disproportionately prevalent and has a cost burden of 2-3 times that of adult patients. Despite this, no widely accepted definition for neonatal sepsis or recommendations for management exist and those created for pediatric patients are significantly limited in their applicability to this unique population. This is in part due to neonates' reliance on an innate immune response (which is developmentally more prominent in the neonate than the immature adaptive immune response) carried out by dysfunctional immune cells, including neutrophils, antigen-presenting cells such as macrophages/monocytes, dendritic cells, etc., natural killer cells, and innate lymphoid regulatory cell sub-sets like iNKT cells, γδ T-cells, etc. Immune checkpoint inhibitors are a family of proteins with primarily suppressive/inhibitory effects on immune and tumor cells and allow for the maintenance of self-tolerance. During sepsis, these proteins are often upregulated and are thought to contribute to the long-term immunosuppression seen in adult patients. Several drugs targeting checkpoint inhibitors, including PD-1 and PD-L1, have been developed and approved for the treatment of various cancers, but no such therapeutics have been approved for the management of sepsis. In this review, we will comparatively discuss the role of several checkpoint inhibitor proteins, including PD-1, PD-L1, VISTA, and HVEM, in the immune response to sepsis in both adults and neonates, as well as posit how they may uniquely propagate their actions through the neonatal innate immune response. We will also consider the possibility of leveraging these proteins in the clinical setting as potential therapeutics/diagnostics that might aid in mitigating neonatal septic morbidity/mortality.
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Affiliation(s)
- Emily Hensler
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States,Graduate Program in Biotechnology, Brown University, Providence, RI, United States
| | - Habesha Petros
- Graduate Program in Biotechnology, Brown University, Providence, RI, United States
| | - Chyna C. Gray
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States,Graduate Program in Biotechnology, Brown University, Providence, RI, United States
| | - Chun-Shiang Chung
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States,Graduate Program in Biotechnology, Brown University, Providence, RI, United States
| | - Alfred Ayala
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States,Graduate Program in Biotechnology, Brown University, Providence, RI, United States,*Correspondence: Alfred Ayala,
| | - Eleanor A. Fallon
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, United States,Graduate Program in Biotechnology, Brown University, Providence, RI, United States
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2
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Eddens T, Parks OB, Williams JV. Neonatal Immune Responses to Respiratory Viruses. Front Immunol 2022; 13:863149. [PMID: 35493465 PMCID: PMC9047724 DOI: 10.3389/fimmu.2022.863149] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/23/2022] [Indexed: 11/30/2022] Open
Abstract
Respiratory tract infections are a leading cause of morbidity and mortality in newborns, infants, and young children. These early life infections present a formidable immunologic challenge with a number of possibly conflicting goals: simultaneously eliminate the acute pathogen, preserve the primary gas-exchange function of the lung parenchyma in a developing lung, and limit long-term sequelae of both the infection and the inflammatory response. The latter has been most well studied in the context of childhood asthma, where multiple epidemiologic studies have linked early life viral infection with subsequent bronchospasm. This review will focus on the clinical relevance of respiratory syncytial virus (RSV), human metapneumovirus (HMPV), and rhinovirus (RV) and examine the protective and pathogenic host responses within the neonate.
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Affiliation(s)
- Taylor Eddens
- Pediatric Scientist Development Program, University of Pittsburgh Medical Center (UPMC) Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States
- Division of Allergy/Immunology, University of Pittsburgh Medical Center (UPMC) Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States
| | - Olivia B. Parks
- Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, PA, United States
| | - John V. Williams
- Division of Pediatric Infectious Diseases, University of Pittsburgh Medical Center (UPMC) Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States
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Costa D, Bonet N, Solé A, González de Aledo-Castillo JM, Sabidó E, Casals F, Rovira C, Nadal A, Marin JL, Cobo T, Castelo R. Genome-wide postnatal changes in immunity following fetal inflammatory response. FEBS J 2020; 288:2311-2331. [PMID: 33006196 PMCID: PMC8049052 DOI: 10.1111/febs.15578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/22/2020] [Accepted: 09/28/2020] [Indexed: 11/29/2022]
Abstract
The fetal inflammatory response (FIR) increases the risk of perinatal brain injury, particularly in extremely low gestational age newborns (ELGANs, < 28 weeks of gestation). One of the mechanisms contributing to such a risk is a postnatal intermittent or sustained systemic inflammation (ISSI) following FIR. The link between prenatal and postnatal systemic inflammation is supported by the presence of well‐established inflammatory biomarkers in the umbilical cord and peripheral blood. However, the extent of molecular changes contributing to this association is unknown. Using RNA sequencing and mass spectrometry proteomics, we profiled the transcriptome and proteome of archived neonatal dried blood spot (DBS) specimens from 21 ELGANs. Comparing FIR‐affected and unaffected ELGANs, we identified 782 gene and 27 protein expression changes of 50% magnitude or more, and an experiment‐wide significance level below 5% false discovery rate. These expression changes confirm the robust postnatal activation of the innate immune system in FIR‐affected ELGANs and reveal for the first time an impairment of their adaptive immunity. In turn, the altered pathways provide clues about the molecular mechanisms triggering ISSI after FIR, and the onset of perinatal brain injury. Databases EGAS00001003635 (EGA); PXD011626 (PRIDE).
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Affiliation(s)
- Daniel Costa
- Department of Pediatrics, Hospital de Figueres, Spain.,Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Núria Bonet
- Genomics Core Facility, Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Amanda Solé
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Proteomics Unit, Centre de Regulació Genòmica (CRG), Barcelona, Spain.,Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | | | - Eduard Sabidó
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Proteomics Unit, Centre de Regulació Genòmica (CRG), Barcelona, Spain.,Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Ferran Casals
- Genomics Core Facility, Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | - Alfons Nadal
- Department of Pathology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Spain
| | - Jose Luis Marin
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centre for Biomedical Research on Rare Diseases (CIBER-ER), University of Barcelona, Spain
| | - Teresa Cobo
- Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centre for Biomedical Research on Rare Diseases (CIBER-ER), University of Barcelona, Spain
| | - Robert Castelo
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Research Programme on Biomedical Informatics, Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain
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4
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Ng S, Strunk T, Lee AH, Gill EE, Falsafi R, Woodman T, Hibbert J, Hancock REW, Currie A. Whole blood transcriptional responses of very preterm infants during late-onset sepsis. PLoS One 2020; 15:e0233841. [PMID: 32479514 PMCID: PMC7263612 DOI: 10.1371/journal.pone.0233841] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/12/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Host immune responses during late-onset sepsis (LOS) in very preterm infants are poorly characterised due to a complex and dynamic pathophysiology and challenges in working with small available blood volumes. We present here an unbiased transcriptomic analysis of whole peripheral blood from very preterm infants at the time of LOS. METHODS RNA-Seq was performed on peripheral blood samples (6-29 days postnatal age) taken at the time of suspected LOS from very preterm infants <30 weeks gestational age. Infants were classified based on blood culture positivity and elevated C-reactive protein concentrations as having confirmed LOS (n = 5), possible LOS (n = 4) or no LOS (n = 9). Bioinformatics and statistical analyses performed included pathway over-representation and protein-protein interaction network analyses. Plasma cytokine immunoassays were performed to validate differentially expressed cytokine pathways. RESULTS The blood leukocyte transcriptional responses of infants with confirmed LOS differed significantly from infants without LOS (1,317 differentially expressed genes). However, infants with possible LOS could not be distinguished from infants with no LOS or confirmed LOS. Transcriptional alterations associated with LOS included genes involved in pathogen recognition (mainly TLR pathways), cytokine signalling (both pro-inflammatory and inhibitory responses), immune and haematological regulation (including cell death pathways), and metabolism (altered cholesterol biosynthesis). At the transcriptional-level cytokine responses during LOS were characterised by over-representation of IFN-α/β, IFN-γ, IL-1 and IL-6 signalling pathways and up-regulation of genes for inflammatory responses. Infants with confirmed LOS had significantly higher levels of IL-1α and IL-6 in their plasma. CONCLUSIONS Blood responses in very preterm infants with LOS are characterised by altered host immune responses that appear to reflect unbalanced immuno-metabolic homeostasis.
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Affiliation(s)
- Sherrianne Ng
- Medical, Molecular and Forensic Sciences, Murdoch University, Perth, WA, Australia
- Division of the Institute of Reproductive and Developmental Biology, Imperial College Parturition Research Group, Imperial College London, London, United Kingdom
- March of Dimes European Prematurity Research Centre, Imperial College London, London, United Kingdom
| | - Tobias Strunk
- Department of Health, Neonatal Directorate, King Edward Memorial Hospital, Child and Adolescent Health Service, Perth, WA, Australia
- Neonatal Infection & Immunity Team, Wesfarmers Centre of Vaccine & Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Amy H. Lee
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erin E. Gill
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Reza Falsafi
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tabitha Woodman
- Medical, Molecular and Forensic Sciences, Murdoch University, Perth, WA, Australia
- Neonatal Infection & Immunity Team, Wesfarmers Centre of Vaccine & Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Julie Hibbert
- Neonatal Infection & Immunity Team, Wesfarmers Centre of Vaccine & Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew Currie
- Medical, Molecular and Forensic Sciences, Murdoch University, Perth, WA, Australia
- Neonatal Infection & Immunity Team, Wesfarmers Centre of Vaccine & Infectious Diseases, Telethon Kids Institute, Perth, WA, Australia
- * E-mail:
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Chacko BK, Wall SB, Kramer PA, Ravi S, Mitchell T, Johnson MS, Wilson L, Barnes S, Landar A, Darley-Usmar VM. Pleiotropic effects of 4-hydroxynonenal on oxidative burst and phagocytosis in neutrophils. Redox Biol 2016; 9:57-66. [PMID: 27393890 PMCID: PMC4939321 DOI: 10.1016/j.redox.2016.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 01/09/2023] Open
Abstract
Metabolic control of cellular function is significant in the context of inflammation-induced metabolic dysregulation in immune cells. Generation of reactive oxygen species (ROS) such as hydrogen peroxide and superoxide are one of the critical events that modulate the immune response in neutrophils. When activated, neutrophil NADPH oxidases consume large quantities of oxygen to rapidly generate ROS, a process that is referred to as the oxidative burst. These ROS are required for the efficient removal of phagocytized cellular debris and pathogens. In chronic inflammatory diseases, neutrophils are exposed to increased levels of oxidants and pro-inflammatory cytokines that can further prime oxidative burst responses and generate lipid oxidation products such as 4-hydroxynonenal (4-HNE). In this study we hypothesized that since 4-HNE can target glycolysis then this could modify the oxidative burst. To address this the oxidative burst was determined in freshly isolated healthy subject neutrophils using 13-phorbol myristate acetate (PMA) and the extracellular flux analyzer. Neutrophils pretreated with 4-HNE exhibited a significant decrease in the oxidative burst response and phagocytosis. Mass spectrometric analysis of alkyne-HNE treated neutrophils followed by click chemistry detected modification of a number of cytoskeletal, metabolic, redox and signaling proteins that are critical for the NADPH oxidase mediated oxidative burst. These modifications were confirmed using a candidate immunoblot approach for critical proteins of the active NADPH oxidase enzyme complex (Nox2 gp91phox subunit and Rac1 of the NADPH oxidase) and glyceraldehyde phosphate dehydrogenase, a critical enzyme in the metabolic regulation of oxidative burst. Taken together, these data suggest that 4-HNE-induces a pleiotropic mechanism to inhibit neutrophil function. These mechanisms may contribute to the immune dysregulation associated with chronic pathological conditions where 4-HNE is generated. Phagocytosis and glycolysis are inhibited in neutrophils by 4-hydroxynonenal. Click chemistry with alkyne-HNE identifies over 100 potential protein targets. Rac1, NOX2 and GAPDH are modified by 4-HNE. The 4-HNE-dependent inhibition of neutrophil function is mediated by a pleiotropic mechanism.
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Affiliation(s)
- Balu K Chacko
- Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, United States; Department of Pathology, University of Alabama at Birmingham, United States
| | - Stephanie B Wall
- Department of Pathology, University of Alabama at Birmingham, United States
| | - Philip A Kramer
- Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, United States; Department of Pathology, University of Alabama at Birmingham, United States
| | - Saranya Ravi
- Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, United States; Department of Pathology, University of Alabama at Birmingham, United States
| | - Tanecia Mitchell
- Department of Urology, University of Alabama at Birmingham, United States
| | - Michelle S Johnson
- Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, United States; Department of Pathology, University of Alabama at Birmingham, United States
| | - Landon Wilson
- Department of Pharmacology and Toxicology, The Targeted Metabolomics and Proteomics Laboratory, University of Alabama at Birmingham, United States
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, The Targeted Metabolomics and Proteomics Laboratory, University of Alabama at Birmingham, United States
| | - Aimee Landar
- Department of Pathology, University of Alabama at Birmingham, United States
| | - Victor M Darley-Usmar
- Mitochondrial Medicine Laboratory, University of Alabama at Birmingham, United States; Department of Pathology, University of Alabama at Birmingham, United States.
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7
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Khan I, Zhang L, Mohammed M, Archer FE, Abukharmah J, Yuan Z, Rizvi SS, Melek MG, Rabson AB, Shi Y, Weinberger B, Vetrano AM. Effects of Wharton's jelly-derived mesenchymal stem cells on neonatal neutrophils. J Inflamm Res 2014; 8:1-8. [PMID: 25678809 PMCID: PMC4317142 DOI: 10.2147/jir.s71987] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background Mesenchymal stem cells (MSCs) have been proposed as autologous therapy for inflammatory diseases in neonates. MSCs from umbilical cord Wharton’s jelly (WJ-MSCs) are accessible, with high proliferative capacity. The effects of WJ-MSCs on neutrophil activity in neonates are not known. We compared the effects of WJ-MSCs on apoptosis and the expression of inflammatory, oxidant, and antioxidant mediators in adult and neonatal neutrophils. Methods WJ-MSCs were isolated, and their purity and function were confirmed by flow cytometry. Neutrophils were isolated from cord and adult blood by density centrifugation. The effects of neutrophil/WJ-MSC co-culture on apoptosis and gene and protein expression were measured. Results WJ-MSCs suppressed neutrophil apoptosis in a dose-dependent manner. WJ-MSCs decreased gene expression of NADPH oxidase-1 in both adult and neonatal neutrophils, but decreased heme oxygenase-1 and vascular endothelial growth factor and increased catalase and cyclooxygenase-2 in the presence of lipopolysaccharide only in adult cells. Similarly, generation of interleukin-8 was suppressed in adult but not neonatal neutrophils. Thus, WJ-MSCs dampened oxidative, vascular, and inflammatory activity by adult neutrophils, but neonatal neutrophils were less responsive. Conversely, Toll-like receptor-4, and cyclooxygenase-2 were upregulated in WJ-MSCs only in the presence of adult neutrophils, suggesting an inflammatory MSC phenotype that is not induced by neonatal neutrophils. Conclusion Whereas WJ-MSCs altered gene expression in adult neutrophils in ways suggesting anti-inflammatory and antioxidant effects, these responses were attenuated in neonatal cells. In contrast, inflammatory gene expression in WJ-MSCs was increased in the presence of adult but not neonatal neutrophils. These effects should be considered in clinical trial design before WJ-MSC-based therapy is used in infants.
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Affiliation(s)
- Imteyaz Khan
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Liying Zhang
- Rutgers Child Health Institute of New Jersey, New Brunswick, NJ, USA
| | - Moiz Mohammed
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Faith E Archer
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Jehan Abukharmah
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Zengrong Yuan
- Rutgers Child Health Institute of New Jersey, New Brunswick, NJ, USA
| | - S Saif Rizvi
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Michael G Melek
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Arnold B Rabson
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA ; Rutgers Child Health Institute of New Jersey, New Brunswick, NJ, USA
| | - Yufang Shi
- Rutgers Child Health Institute of New Jersey, New Brunswick, NJ, USA
| | - Barry Weinberger
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Anna M Vetrano
- Department of Pediatrics, Division of Neonatology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA ; Rutgers Child Health Institute of New Jersey, New Brunswick, NJ, USA
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Abstract
Neonates have little immunological memory and a developing immune system, which increases their vulnerability to infectious agents. Recent advances in the understanding of neonatal immunity indicate that both innate and adaptive responses are dependent on precursor frequency of lymphocytes, antigenic dose and mode of exposure. Studies in neonatal mouse models and human umbilical cord blood cells demonstrate the capability of neonatal immune cells to produce immune responses similar to adults in some aspects but not others. This review focuses mainly on the developmental and functional mechanisms of the human neonatal immune system. In particular, the mechanism of innate and adaptive immunity and the role of neutrophils, antigen presenting cells, differences in subclasses of T lymphocytes (Th1, Th2, Tregs) and B cells are discussed. In addition, we have included the recent developments in the neonatal mouse immune system. Understanding neonatal immunity is essential to development of therapeutic vaccines to combat newly emerging infectious agents.
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Affiliation(s)
- Saleem Basha
- Center for Infectious Disease and Immunology, Rochester General Hospital Research Institute, 1425 Portland Avenue, Rochester, NY 14621, USA
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9
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Intermittent or sustained systemic inflammation and the preterm brain. Pediatr Res 2014; 75:376-80. [PMID: 24429547 PMCID: PMC3943674 DOI: 10.1038/pr.2013.238] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/13/2013] [Indexed: 12/22/2022]
Abstract
Exposure to perinatal infection and inflammation is associated with an increased risk for neonatal brain damage and developmental disabilities. In this integrated mechanism review, we discuss evidence in support of the contention that the preterm newborn is capable of intermittent or sustained systemic inflammation (ISSI), which appears to contribute more to adverse neurodevelopmental outcomes in preterm infants than does shorter duration inflammation.
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10
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Abstract
PURPOSE OF REVIEW Sepsis is a serious complication in preterm and term infants, yet our understanding of how neonates respond to infection remains poorly defined. RECENT FINDINGS We describe our current clinical, cellular and molecular understanding of the neonatal host systemic response to infection. We find that host resilience essentially relies on innate immune mechanisms despite there being a complete repertoire of cellular components of the adaptive immune arm. The functional interplay between metabolism, immunity and microbiome further suggests that neonatal vulnerability to infection is not simply due to immaturity of the immune system but how immune homeostasis is regulated. Further research is required for exploring regulatory homeostatic mechanisms between innate and adaptive responses and microbiome colonization at birth, but which can impart an adverse trajectory to infection. SUMMARY The vulnerability and resilience against infection in neonates, including extreme preterm infants, still remains poorly understood. We advance the view that greater consideration should be given to understanding the set point in the regulation of homeostatic control of innate and adaptive immunity and its interplay with metabolism and the newly acquired microbiome.
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Affiliation(s)
- Peter Ghazal
- Division of Pathway Medicine, University of Edinburgh, Edinburgh, UK.
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11
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Iliodromiti Z, Zygouris D, Sifakis S, Pappa KI, Tsikouras P, Salakos N, Daniilidis A, Siristatidis C, Vrachnis N. Acute lung injury in preterm fetuses and neonates: mechanisms and molecular pathways. J Matern Fetal Neonatal Med 2013; 26:1696-704. [PMID: 23611524 DOI: 10.3109/14767058.2013.798284] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Acute lung injury (ALI) results in high morbidity and mortality among preterm neonates and efforts have therefore been devoted to both antenatal and postnatal prevention of the disease. ALI is the result of an inflammatory response which is triggered by a variety of different mechanisms. It mostly affects the fetal lung and, in particular, causes damage to the integrity of the lung's alveolar-capillary unit while weakening its cellular linings. Chemotactic activity and inflammatory products, such as proinflammatory cytokines TNF-α, IL-1, IL-6, IL-11, VEGF,TGF-α and TGF-β, provoke serious damage to the capillary endothelium and the alveolar epithelium, resulting in hyaline membrane formation and leakage of protein-rich edema fluid into the alveoli. Chorioamnionitis plays a major part in triggering fetal lung inflammation, while mechanical ventilation, the application of which is frequently necessary in preterm neonates, also causes ALI by inducing proinflammatory cytokines. Many different ventilation-strategies have been developed in order to reduce potential lung injury. Furthermore, tissue injury may occur as a result of injurious oxygen by-products (Reactive Oxygen Species, ROS), secondary to hyperoxia. Knowledge of the inflammatory pathways that connect intra-amniotic inflammation and ALI can lead to the formulation of novel interventional procedures. Future research should concentrate on the pathophysiology of ALI in preterm neonates and οn possible pharmaceutical interventions targeting prevention and/or resolution of ALI.
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Affiliation(s)
- Zoe Iliodromiti
- 2nd Department of Obstetrics and Gynecology, University of Athens Medical School, Aretaieio Hospital , Athens , Greece
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12
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Bekkering S, Torensma R. Another look at the life of a neutrophil. World J Hematol 2013; 2:44-58. [DOI: 10.5315/wjh.v2.i2.44] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 04/04/2013] [Accepted: 04/16/2013] [Indexed: 02/05/2023] Open
Abstract
Neutrophils are considered as the privates of the innate immune system. They are born in the bone marrow, migrate to the tissues where they kill putative intruders. After their job they are quickly removed from the battlefield by macrophages. This view of a predetermined pathway fitted nicely in their short lifespan of 5 h. However, recent studies indicated that their lifespan was in the order of several days. Recently, it became clear that neutrophils have functions beyond killing of pathogens. The reported half-life of 5 h is hardly compatible with those functions. Moreover, the organism actively invests in rescuing primed neutrophils from clearance by the body. It appears that their half-life is highly dependent on the method used to measure their life span. Here, we discuss the literature and show that neutrophils compartmentalize which could explain partially the differences reported for their lifespan. Moreover, the methodology to label neutrophils ex-vivo could have similar deteriorating effects on their lifespan as found for transfused red blood cells.
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13
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Decreased anti-inflammatory responses to vitamin D in neonatal neutrophils. Mediators Inflamm 2011; 2011:598345. [PMID: 22219556 PMCID: PMC3246794 DOI: 10.1155/2011/598345] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/19/2011] [Accepted: 09/19/2011] [Indexed: 11/17/2022] Open
Abstract
Neutrophil activity is prolonged in newborns, suggesting decreased exposure and/or responses to immunosuppressive modulators, such as 1,25-hydroxyvitamin D(3) (1,25-vit D(3)). We hypothesized that 1,25-vit D(3) suppresses neutrophil activation and that this response is impaired in newborns. Consistent with this, 1,25-vit D(3) decreased LPS-induced expression of macrophage inflammatory protein-1β and VEGF in adult, but not neonatal, neutrophils. Expression of vitamin D receptor (VDR) and 25-hydroxyvitamin D(3)-1α-hydroxylase was reduced in neonatal, relative to adult neutrophils. Moreover, 1,25-vit D(3) induced VDR gene expression in activated adult, but not neonatal, neutrophils. 1,25-vit D(3) also suppressed expression of cyclooxygenase-2 and induced expression of 5-lipoxygenase in LPS-exposed adult neutrophils, while neonatal cells were not affected. 1,25-vit D(3) had no effect on respiratory burst in either adult or neonatal cells. Anti-inflammatory activity of vitamin D is impaired in neonatal neutrophils, and this may be due to decreased expression of VDR and 1α-hydroxylase. Insensitivity to 1,25-vit D(3) may contribute to chronic inflammation in neonates.
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14
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Rashmi R, Schnulle PM, Maddox AC, Armbrecht ES, Koenig JM. Flice inhibitory protein is associated with the survival of neonatal neutrophils. Pediatr Res 2011; 70:327-31. [PMID: 21691254 PMCID: PMC3166417 DOI: 10.1203/pdr.0b013e3182290062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neonatal polymorphonuclear leukocytes (PMN) exhibit delayed apoptosis both constitutively and under inflammatory conditions, and evidence has linked PMN longevity to the presence of antiapoptotic proteins. Activation of the survival-associated transcription factor, nuclear factor kappa B (NF-κB), promotes the synthesis of several antiapoptotic proteins including Flice inhibitory protein (FLIP). Neonatal and adult PMN were compared in this study to test the hypothesis that FLIP modulates age-related apoptosis. Expression of the short isoform, FLIP-S, was prominent at baseline and persisted during spontaneous apoptosis in neonatal PMN, whereas basal expression was lower and decreased under the same conditions in adult PMN. Stable FLIP-S expression in neonatal PMN was associated with a relative resistance to apoptosis in response to the protein synthesis inhibitor, cycloheximide (CHX), or the NF-κB inhibitor, gliotoxin. In contrast, similar treatment of adult PMN promoted greater overall apoptosis accompanied by FLIP degradation. Nuclear levels of phosphorylated p65, a critical NF-κB dimer, were relatively robust in neonatal PMN under basal conditions or after stimulation with TNF-α, a cytokine that induces FLIP. In conclusion, persistent FLIP-S expression is involved in the longevity of neonatal PMN, and our data suggest a contribution of NF-κB signaling and related survival mechanisms.
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Affiliation(s)
- Ramachandran Rashmi
- Department of Pediatrics, St. Louis University School of Medicine, St. Louis, MO 63104, USA
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15
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Melvan JN, Bagby GJ, Welsh DA, Nelson S, Zhang P. Neonatal sepsis and neutrophil insufficiencies. Int Rev Immunol 2010; 29:315-48. [PMID: 20521927 DOI: 10.3109/08830181003792803] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sepsis has continuously been a leading cause of neonatal morbidity and mortality despite current advances in chemotherapy and patient intensive care facilities. Neonates are at high risk for developing bacterial infections due to quantitative and qualitative insufficiencies of innate immunity, particularly granulocyte lineage development and response to infection. Although antibiotics remain the mainstay of treatment, adjuvant therapies enhancing immune function have shown promise in treating sepsis in neonates. This article reviews current strategies for the clinical management of neonatal sepsis and analyzes mechanisms underlying insufficiencies of neutrophil defense in neonates with emphasis on new directions for adjuvant therapy development.
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Affiliation(s)
- John Nicholas Melvan
- Department of Physiology and Alcohol Research Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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16
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Vetrano AM, Laskin DL, Archer F, Syed K, Gray JP, Laskin JD, Nwebube N, Weinberger B. Inflammatory effects of phthalates in neonatal neutrophils. Pediatr Res 2010; 68:134-9. [PMID: 20453712 PMCID: PMC2908957 DOI: 10.1203/pdr.0b013e3181e5c1f7] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hospitalized infants are exposed to numerous devices containing the plasticizer di-(2-ethylhexyl) phthalate. Urinary levels of the phthalate metabolite, mono-(2-ethylhexyl) phthalate (MEHP), are markedly elevated in premature infants. Phthalates inactivate peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a nuclear transcription factor that mediates the resolution of inflammation, a process impaired in neonates. We speculate that this increases their susceptibility to MEHP, and this was analyzed. MEHP inhibited neutrophil apoptosis; neonatal cells were more sensitive than adult cells. In neonatal, but not in adult neutrophils, MEHP also inhibited chemotaxis, stimulated oxidative metabolism, and up-regulated expression of NADPH oxidase-1. In both adult and neonatal neutrophils, MEHP stimulated IL-1beta and VEGF production, whereas IL-8 production was stimulated only in adult cells. In contrast, MEHP-inhibited production of MIP-1beta by adult cells, and Regulated on Activation Normal T Cell Expressed and Secreted (RANTES) by neonatal neutrophils. The effects of MEHP on apoptosis and oxidative metabolism in neonatal cells were reversed by the PPAR-gamma agonist, troglitazone. Whereas troglitazone had no effect on MEHP-induced alterations in inflammatory protein or chemokine production, constitutive IL-8 and MIP-1beta production was reduced in adult neutrophils, and RANTES and MIP-1beta in neonatal cells. These findings suggest that neonatal neutrophils are more sensitive to phthalate-mediated inhibition of PPAR-gamma, which may be related to decreased anti-inflammatory signaling.
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Affiliation(s)
- Anna M Vetrano
- Department of Pediatrics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901, USA
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Wirbelauer J, Thomas W, Speer CP. Response of leukocytes and nucleated red blood cells in very low-birth weight preterm infants after exposure to intrauterine inflammation. J Matern Fetal Neonatal Med 2010; 24:348-53. [PMID: 20608804 DOI: 10.3109/14767058.2010.497568] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To test the hypothesis if very immature preterm infants exposed to chorioamnionitis would exhibit increased numbers of leukocytes, neutrophils, and nucleated red blood cells (NRBC) in peripheral blood. STUDY DESIGN Preterm infants with birth weight <1500 g were prospectively evaluated. Blood cells were counted within the first hour of life in infants exposed to histological chorioamnionitis and controls. RESULTS Birth weight, gestational age, and sex did not differ between the groups (n = 71). Seventeen infants who were exposed to chorioamnionitis had significantly higher counts of leukocytes, neutrophils, and immature neutrophils after birth. However, there was no difference in the number of circulating NRBCs between both groups. In contrast, there was a tendency towards an increased NRBC count in the control group. CONCLUSION Preterm infants exposed to chorioamnionitis elicited a strong inflammatory response as reflected by increased numbers of leukocytes and neutrophils. However, chorioamnionitis did not induce an increase in numbers of NRBC.
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Affiliation(s)
- Johannes Wirbelauer
- University Children's Hospital, University of Wuerzburg, Wuerzburg, Germany.
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18
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Abstract
Neonatal septic shock is a devastating condition associated with high morbidity and mortality. Definitions for the sepsis continuum and treatment algorithms specific for premature neonates are needed to improve studies of septic shock and assess benefit from clinical interventions. Unique features of the immature immune system and pathophysiologic responses to sepsis, particularly those of extremely preterm infants, necessitate that clinical trials consider them as a separate group. Keen clinical suspicion and knowledge of risk factors will help to identify those neonates at greatest risk for development of septic shock. Genomic and proteomic approaches, particularly those that use very small sample volumes, will increase our understanding of the pathophysiology and direct the development of novel agents for prevention and treatment of severe sepsis and shock in the neonate. Although at present antimicrobial therapy and supportive care remain the foundation of treatment, in the future immunomodulatory agents are likely to improve outcomes for this vulnerable population.
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Abstract
Neonatal sepsis continues to take a devastating toll globally. Although adequate to protect against invasive infection in most newborns, the distinct function of neonatal innate host defense coupled with impairments in adaptive immune responses increases the likelihood of acquiring infection early in life, with subsequent rapid dissemination and death. Unique differences exist between neonates and older populations with respect to the capacity, quantity, and quality of innate host responses to pathogens. Recent characterization of the age-dependent maturation of neonatal innate immune function has identified novel translational approaches that may lead to improved diagnostic, prophylactic, and therapeutic modalities.
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20
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Nguyen CN, Schnulle PM, Chegini N, Luo X, Koenig JM. Neonatal neutrophils with prolonged survival secrete mediators associated with chronic inflammation. Neonatology 2010; 98:341-7. [PMID: 20551711 PMCID: PMC2969107 DOI: 10.1159/000309007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Accepted: 03/26/2010] [Indexed: 01/13/2023]
Abstract
BACKGROUND The resolution of inflammation involves the efficient removal of apoptotic neutrophils (PMN). However, a subpopulation of PMN that are resistant to apoptosis may contribute to PMN persistence in tissues, an early hallmark of chronic inflammation. We previously made observations that neonatal PMN with prolonged survival had augmented expression of CD18/CD11b, an adhesion molecule critical to inflammation. OBJECTIVES The objectives of this study were to test the hypothesis that surviving neonatal PMN retain the capacity to secrete key mediators associated with chronic inflammation. METHODS We profiled cytokine and chemokine secretion patterns of lipopolysaccharide (LPS)-stimulated neonatal and adult PMN using multicytokine array and ELISA. RESULTS We observed that surviving 24-hour neonatal PMN stimulated with LPS had enhanced secretion of interleukin (IL)-8, a chemokine involved in PMN activation and recruitment. In addition, 24-hour neonatal PMN secreted levels of monocyte inhibitory protein (MIP)-1β that were higher than those secreted by 0-hour PMN, but amounts of IL-1 receptor antagonist (IL-1Ra) were lower. CONCLUSIONS The results of the present study extend previous observations of augmented function in surviving neonatal neutrophils, and further suggest their potential contribution to the pathogenesis of inflammatory disorders in neonates.
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Affiliation(s)
- Caroline N Nguyen
- Department of Pediatrics, University of Florida, Gainesville, Fla, USA
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21
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Gille C, Steffen F, Lauber K, Keppeler H, Leiber A, Spring B, Poets CF, Orlikowsky TW. Clearance of apoptotic neutrophils is diminished in cord blood monocytes and does not lead to reduced IL-8 production. Pediatr Res 2009; 66:507-12. [PMID: 19668110 DOI: 10.1203/pdr.0b013e3181b9b470] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Phagocytosis of apoptotic cells, e.g., neutrophils, by monocytes is essential for resolution of inflammation. Delayed removal leads to secondary necrosis, perpetuating inflammation, and tissue destruction. Common histologic features in neonatal chronic inflammatory disorders are an accumulation of apoptotic cells in inflamed tissues. We hypothesized that apoptotic cell removal by monocytes is compromised in newborns. PKH-26 labeled autologous or allogeneic apoptotic neutrophils were fed to monocytes of adult donors (PBMO) and cord blood (CBMO), and phagocytic activity was analyzed by flow cytometry and confocal microscopy. Relative mRNA-expression levels of 21 surface receptors and bridging molecules relevant for apoptotic cell removal were measured, as was postphagocytic IL-8 production upon LPS-stimulation. Compared with PBMO, CBMO exhibited a significantly diminished phagocytotic competence for autologous and allogeneic apoptotic neutrophils. mRNA-expression levels of milk fat globule-EGF factor 8 and T cell immunoglobulin- and mucin-domain-containing molecule, two crucial members of the phagocytic synapse of apoptotic cell removal, were reduced in CBMO. In PBMO, interaction with autologous apoptotic neutrophils reduced LPS-induced IL-8 production whereas it was enhanced in CBMO. Our data suggest a specific defect in CBMO during clearance of apoptotic neutrophils resulting in impaired anti-inflammatory capacity.
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Affiliation(s)
- Christian Gille
- Department of Neonatology, University Children's Hospital, Tuebingen, Germany
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Rashmi R, Bode BP, Panesar N, King SB, Rudloff JR, Gartner MR, Koenig JM. Siglec-9 and SHP-1 are differentially expressed in neonatal and adult neutrophils. Pediatr Res 2009; 66:266-71. [PMID: 19542910 PMCID: PMC2753195 DOI: 10.1203/pdr.0b013e3181b1bc19] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neonatal PMN (polymorphonuclear neutrophils) exhibit altered inflammatory responsiveness and greater longevity compared with adult PMN; however, the involved mechanisms are incompletely defined. Receptors containing immunoreceptor tyrosine-based inhibitory motif (ITIM) domains promote apoptosis by activating inhibitory phosphatases, such as Src homology domain 2-containing tyrosine phosphatase-1 (SHP-1), that block survival signals. Sialic acid-binding immunoglobulin-like lectin (Siglec)-9, an immune inhibitory receptor with an ITIM domain, has been shown to induce cell death in adult PMN in association with SHP-1. To test our hypothesis that neonatal PMN inflammatory function may be modulated by unique Siglec-9 and SHP-1 interactions, we compared expression of these proteins in adult and neonatal PMN. Neonatal PMN exhibited diminished cellular expression of Siglec-9, which was phosphorylated in the basal state. Granulocyte-macrophage colony-stimulating factor (GM-CSF) treatment decreased Siglec-9 phosphorylation levels in neonatal PMN but promoted its phosphorylation in adult PMN, observations associated with altered survival signaling. Although SHP-1 expression was also diminished in neonatal PMN, GM-CSF treatment had minimal effect on phosphorylation status. Further analysis revealed that Siglec-9 and SHP-1 physically interact, as has been observed in other immune cells. Our data suggest that age-specific interactions between Siglec-9 and SHP-1 may influence the altered inflammatory responsiveness and longevity of neonatal PMN.
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Affiliation(s)
- Ramachandran Rashmi
- Department of Pediatrics, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
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23
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Gille C, Leiber A, Mundle I, Spring B, Abele H, Spellerberg B, Hartmann H, Poets CF, Orlikowsky TW. Phagocytosis and postphagocytic reaction of cord blood and adult blood monocyte after infection with green fluorescent protein-labeled Escherichia coli and group B Streptococci. CYTOMETRY PART B-CLINICAL CYTOMETRY 2009; 76:271-84. [PMID: 19288547 DOI: 10.1002/cyto.b.20474] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Neonatal sepsis is characterized by an excessive inflammatory response induced by immune cells (monocytes). We investigated the initial stage of monocyte-pathogen interaction, i.e. bacterial ingestion and degradation at the single-cell level, by comparing a new flow cytometric procedure with culture methods. We also examined the hypothesis that, in terms of phagocytosis-induced cell death (PICD), phenotype, or cytokine production, cord blood monocytes (CBMO) differ from monocytes derived from adults (peripheral blood monocytes, PBMO). METHODS Phagocytosis and intracellular degradation were assessed by means of flow cytometry and bacterial cultures of green fluorescent protein-labeled group B Streptococci (GBS) and Escherichia coli. The production of reactive oxygen species (ROS) was measured through luminol-enhanced chemiluminescence. Apoptosis, phenotype, and cytokine production were assessed through flow cytometry. RESULTS Flow cytometry and bacterial cultures showed no difference between phagocytosis and degradation of GBS and E. coli by PBMO and CBMO. A high correlation between both methods was observed. No difference in ROS production was evident. In comparison with PBMO, CBMO apoptosis was lower after exposure to GBS and E. coli. Similarities were found between nonapoptotic monocytes and pro-inflammatory monocytes. CONCLUSIONS PICD is lower in CBMO during the early stages of monocyte-pathogen interaction. Our results emphasize that monocyte apoptosis has a potential role in tailoring the immune response in neonatal sepsis.
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Affiliation(s)
- Ch Gille
- Department of Neonatology, University Children's Hospital, 72076 Tübingen, Germany
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24
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Koenig JM, Keenan WJ. Group B streptococcus and early-onset sepsis in the era of maternal prophylaxis. Pediatr Clin North Am 2009; 56:689-708, Table of Contents. [PMID: 19501699 PMCID: PMC2702484 DOI: 10.1016/j.pcl.2009.04.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite an era of marked success with universal screening, Group B Streptococcus (GBS) continues to be an important cause of early-onset sepsis, and thus remains a significant public health issue. Improved eradication of GBS colonization and disease may involve universal screening in conjunction with rapid diagnostic technologies or other novel approaches. Given the complications and potential limitations associated with maternal intrapartum prophylaxis, however, vaccines may be the most effective means of preventing neonatal GBS disease. The global utility of conjugated GBS vaccines may be hampered by the variability of serotypes in diverse populations and geographic locations. Modern technologies, such as those involving proteomics and genomic sequencing, are likely to hasten the development of a universal vaccine against GBS.
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Affiliation(s)
- Joyce M Koenig
- Department of Pediatrics, Division of Neonatal-Perinatal Medicine, Saint Louis University, Saint Louis, MO 63104, USA.
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25
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Wennekamp J, Henneke P. Induction and termination of inflammatory signaling in group B streptococcal sepsis. Immunol Rev 2009; 225:114-27. [PMID: 18837779 DOI: 10.1111/j.1600-065x.2008.00673.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SUMMARY Group B streptococcus (GBS) is part of the normal genital and gastrointestinal flora in healthy humans. However, GBS is a major cause of sepsis and meningitis in newborn infants in the Western world and an important pathogen in many developing countries. The dissection of the host response to GBS may increase the general understanding of innate immunity in sepsis, because newborn infants lack a sufficient adaptive response. Inflammatory signal induction in macrophages by GBS seems largely preserved in newborn infants, as shown both in vitro and in vivo. The engagement of Toll-like receptor 2 (TLR2) by lipoproteins and a myeloid differentiation factor 88 (MyD88)--dependent pathway induced by GBS cell wall are both important in this context. TLR2 activation of microglia by GBS induces neuronal damage, which might account for the high morbidity of GBS meningitis. At the same time, TLR2 mediates activation-induced cell death (AICD), a process involved in the containment of inflammation. In newborn infants, AICD and anti-bacterial polymorphonuclear leukocyte activity appears to be compromised. Accordingly, neonatal aberrations in the pathogen-specific negative control of inflammatory signaling are likely to contribute to excessive inflammation and neurological sequelae in GBS sepsis and meningitis.
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Affiliation(s)
- Julia Wennekamp
- Centre for Pediatrics and Adolescent Medicine, University Medical Centre, Freiburg, Germany
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26
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Weinberger B, Quizon C, Vetrano AM, Archer F, Laskin JD, Laskin DL. Mechanisms mediating reduced responsiveness of neonatal neutrophils to lipoxin A4. Pediatr Res 2008; 64:393-8. [PMID: 18535486 PMCID: PMC2651411 DOI: 10.1203/pdr.0b013e318180e4af] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Lipoxin A4 is an eicosanoid that plays a key role in the resolution of neutrophilic inflammation. In these studies, we investigated the hypothesis that responses to lipoxin A4 are impaired in neonates, relative to adults. Lipoxin A4 was found to inhibit chemotaxis and respiratory burst in adult neutrophils. In contrast, it had no effect on these activities in neonatal neutrophils. In addition, while lipoxin A4 augmented apoptosis in LPS-treated adult neutrophils, apoptosis in neonatal cells was not affected by lipoxin A4 alone or in combination with LPS. The biologic actions of anti-inflammatory eicosanoids are mediated, in part, via the transcription factor peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Expression of PPAR-gamma mRNA and its target gene, neutrophil gelatinase-associated lipocalin (NGAL), were significantly reduced in neonatal cells when compared with adult cells. Moreover, whereas treatment of adult neutrophils with lipoxin A4 increased PPAR-gamma expression, no effects were observed in neonatal cells. 5- and 15-lipoxygenase, enzymes required for the synthesis of lipoxin A4, were also reduced in neonatal neutrophils. These findings suggest that the anti-inflammatory activity of lipoxin A4 is impaired in neonatal neutrophils and that this is due, in part, to reduced PPAR-gamma signaling. This may contribute to diseases associated with chronic inflammation in neonates.
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Affiliation(s)
- Barry Weinberger
- Department of Pediatrics, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901, USA.
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Abstract
Inflammation is important in the development of bronchopulmonary dysplasia (BPD). Polymorphonuclear cells and macrophages and proinflammatory cytokines/chemokines denote early inflammation in clinical scenarios such as in utero inflammation with chorioamnionitis or initial lung injury associated with respiratory distress syndrome or ventilator-induced lung injury. The persistence and non-resolution of lung inflammation contributes greatly to BPD, including altering the lung's ability to repair, contributing to fibrosis, and inhibiting secondary septation, alveolarization, and normal vascular development. Further understanding of the role of inflammation in the pathogenesis of BPD, in particular, during the chronic inflammatory period, offers us the opportunity to develop inflammation-related prevention and treatment strategies of this disease that has long-standing consequences for very premature infants.
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Gille C, Leiber A, Spring B, Kempf VAJ, Loeffler J, Poets CF, Orlikowsky TW. Diminished phagocytosis-induced cell death (PICD) in neonatal monocytes upon infection with Escherichia coli. Pediatr Res 2008; 63:33-8. [PMID: 18043500 DOI: 10.1203/pdr.0b013e31815b8e9f] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An imbalance in apoptosis or survival of immune cells plays an essential role in the pathophysiology of sepsis. Phagocytosis-induced cell death (PICD) is a common result of the pathogen-host cell interaction mediated by reactive oxygen species (ROS). Neonatal sepsis is frequently characterized by hyperinflammation. Cord blood monocytes (CBMO) are equivalent to monocytes of adults [peripheral blood monocytes (PBMO)], both in terms of phagocytosis and killing of Escherichia coli. We investigated whether CBMO are less sensitive toward PICD compared with PBMO. Monocytes were infected with green fluorescent protein (GFP)-labeled E. coli. Phagocytic activity, cell-count, Annexin V staining, hypoploid DNA content, CD95 and CD95L expression, and caspase-8 and -9 activities were analyzed by flow cytometry, ROS production by chemiluminescence, and CD95L mRNA expression by reverse-transcriptase polymerase chain reaction. With equal phagocytic activity and ROS production, PBMO cell count was decreased by 82 +/- 6% versus 28 +/- 8% for CBMO after infection. Annexin V binding was enhanced fivefold on PBMO; 56 +/- 15% of PBMO showed a hypodiploid DNA content compared with 9 +/- 6% of CBMO. Caspases CD95L and CD95L mRNA were up-regulated in PBMO. Our results indicate that CBMO are less sensitive toward E. coli-mediated PICD than PBMO. Modifying monocyte apoptosis may be a target for future interventions in sepsis.
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Affiliation(s)
- Christian Gille
- Department of Neonatology, University Children's Hospital, Tuebingen, 72076, Germany
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Molloy EJ, O'Neill AJ, Grantham-Sloan JJ, Webb DW, Watson RWG. Maternal and neonatal lipopolysaccharide and Fas responses are altered by antenatal risk factors for sepsis. Clin Exp Immunol 2007; 151:244-50. [PMID: 18062800 DOI: 10.1111/j.1365-2249.2007.03540.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The diagnosis of neonatal sepsis is difficult, resulting in unnecessary treatment to minimize morbidity and mortality. We hypothesized that exposure to antenatal risk factors for sepsis alters the perinatal neutrophil phenotype. The study setting was a tertiary referral university-affiliated maternity and neonatal hospital. Neutrophils from adults, normal neonates, neonates with antenatal sepsis risk factors and their respective maternal samples were incubated alone, with agonistic Fas antibody or with lipopolysaccharide (LPS). Surface receptor CD11b expression and the percentage apoptosis (persistent inflammatory response) were assessed using flow cytometry. Both mothers and asymptomatic neonates exposed to maternal sepsis risk factors had increased spontaneous neutrophil apoptosis compared to their respective controls. Infants with sepsis were LPS and Fas hyporesponsive. Maternal neutrophils had a delay in apoptosis in all groups with enhanced LPS and Fas responses associated with neonatal sepsis. CD11b expression was not altered significantly between groups. Maternal neutrophil function is altered in neonatal sepsis and may have a diagnostic role. Neonatal sepsis was associated with LPS hyporesponsiveness, potentially increasing susceptibility to infection.
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Affiliation(s)
- E J Molloy
- Department of Surgery, Mater Misericordiae University Hospital, Conway Institute of Biomolecular and Biomedical Research, Dublin, Ireland.
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30
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Weinberger B, Vetrano AM, Syed K, Murthy S, Hanna N, Laskin JD, Laskin DL. Influence of labor on neonatal neutrophil apoptosis, and inflammatory activity. Pediatr Res 2007; 61:572-7. [PMID: 17413861 DOI: 10.1203/pdr.0b013e318045be38] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Neutrophil apoptosis is impaired in neonates, and this contributes to prolonged inflammation and tissue injury in infants after infection or trauma. In the present studies, we investigated whether labor generates mediators that further suppress apoptosis. We found that neutrophil apoptosis was reduced in neonates exposed to labor, when compared with infants delivered by cesarean section before labor. This was not due to alterations in caspase-3 or inhibitor of apoptosis protein-2 (IAP-2). In contrast, labor primed neutrophils to express tumor necrosis factor alpha (TNF-alpha), suggesting that proinflammatory mediators contribute to reduced apoptosis after labor. Eicosanoids generated via cyclooxygenase-2 (Cox-2) and lipoxygenase (Lox) also regulate neutrophil apoptosis. 15-Lox, which generates proapoptotic lipoxins, but not Cox-2, was greater in neutrophils before labor, relative to cells exposed to labor. Anti-inflammatory eicosanoids exert their effects in part via peroxisome proliferator-activated receptor gamma (PPAR-gamma). Expression of gelatinase-associated lipocalin and catalase, two markers of PPAR-gamma activity, were increased in neonatal neutrophils before labor, relative to cells exposed to labor. These findings suggest that the anti-inflammatory environment is maintained before labor, in part, by eicosanoids. Although increased neutrophil longevity after labor is important for host defense in the immediate newborn period, it may contribute to inflammatory or oxidative injury in susceptible infants.
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Affiliation(s)
- Barry Weinberger
- Department of Pediatrics/Neonatology, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
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Abstract
Increasing evidence indicates that bronchopulmonary dysplasia (BPD) results, at least in part, from an imbalance between pro-inflammatory and anti-inflammatory mechanisms, with a persistent imbalance that favours pro-inflammatory mechanisms. The inflammatory response is characterised by an accumulation of neutrophils and macrophages in the airways and pulmonary tissue of preterm infants and, moreover, by an arsenal of pro-inflammatory mediators which affect the alveolar capillary unit and tissue integrity. As well as pro-inflammatory cytokines and toxic oxygen radicals, various lipid mediators as well as potent proteases may be responsible for acute lung injury. During the last decade it has become evident that multiple pre- and postnatal events contribute to the development of BPD in preterm infants. Chorioamnionitis and cytokine exposure in utero, plus sequential lung injury caused by postnatal resuscitation, oxygen toxicity, volu-, barotrauma and infection all lead to a pulmonary inflammatory response which is most probably associated with aberrant wound healing and an inhibition of alveolarisation as well as vascular development in the immature lungs of very preterm infants, causing the 'new BPD'.
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Affiliation(s)
- Christian P Speer
- University Children's Hospital, Josef-Schneider-Str. 2, 97080 Wuerzburg, Germany.
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33
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Lindemans CA, Coffer PJ, Schellens IMM, de Graaff PMA, Kimpen JLL, Koenderman L. Respiratory syncytial virus inhibits granulocyte apoptosis through a phosphatidylinositol 3-kinase and NF-kappaB-dependent mechanism. THE JOURNAL OF IMMUNOLOGY 2006; 176:5529-37. [PMID: 16622022 DOI: 10.4049/jimmunol.176.9.5529] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract disease in children. It is associated with increased neutrophil numbers in the airway. In this study, we assessed whether this ssRNA virus can directly influence granulocyte longevity. By culturing RSV with granulocytes, it was observed that virus delays both constitutive neutrophil and eosinophil apoptosis. Using pharmacological inhibitors, the RSV-induced delay in neutrophil apoptosis was found to be dependent on both PI3K and NF-kappaB, but not p38 MAPK or MEK1/MEK2 activation. Using blocking Abs and a reporter cell line, we were able to exclude TLR4 as the receptor responsible for mediating RSV-induced delay in neutrophil apoptosis. The antiapoptotic effect was abrogated by preincubation with the lysosomotropic agent chloroquine, indicating the requirement for endolysosomal internalization. Furthermore, addition of ssRNA, a ligand for the intracellular TLR7/TLR8, also inhibited neutrophil apoptosis, suggesting that intracellular TLRs could be involved in induction of the antiapoptotic effect. Using the BioPlex cytokine detection assay (Bio-Rad), we found that IL-6 was present in supernatants from RSV-exposed neutrophils. IL-6 was found to inhibit neutrophil apoptosis, suggesting that there is an autocrine or paracrine antiapoptotic role for IL-6. Finally, RSV treatment of neutrophils resulted in increased expression of the antiapoptotic Bcl-2 protein Mcl-1. Taken together, our findings suggest involvement of multiple intracellular mechanisms responsible for RSV-induced survival of granulocytes and point toward a role for intracellular TLRs in mediating these effects.
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Affiliation(s)
- Caroline A Lindemans
- Department of Pulmonary Diseases, University Medical Center, Lundlaan 6, 3508 AB Utrecht, The Netherlands
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Firth MA, Shewen PE, Hodgins DC. Passive and active components of neonatal innate immune defenses. Anim Health Res Rev 2006; 6:143-58. [PMID: 16583779 DOI: 10.1079/ahr2005107] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Innate immune defenses are crucial for survival in the first days and weeks of life. At birth, newborns are confronted with a vast array of potentially pathogenic microorganisms that were not encountered in utero. At this age, cellular components of the adaptive immune system are in a naive state and are slow to respond. Antibodies received from the dam are essential for defense, but represent a finite and dwindling resource. Innate components of the immune system detect pathogen-associated molecular patterns (PAMPs) on microorganisms (and their products) by means of pattern-recognition receptors (PRRs). Soluble mediators of the innate system such as complement proteins, pentraxins, collectins, ficolins, defensins, lactoferrin, lysozyme etc. can bind to structures on pathogens, leading to agglutination, interference with receptor binding, opsonization, neutralization, direct membrane damage and recruitment of additional soluble and cellular elements through inflammation. Cell-associated receptors such as the Toll-like receptors (TLRs) can activate cells and coordinate responses (both innate and adaptive). In this paper, accumulated knowledge of the receptors, soluble and cellular elements that contribute to innate defenses of young animals is reviewed. Research interest in this area has been intermittent, and the literature varies in quantity and quality. It is hoped that documentation of the limitations of our knowledge base will lead to more extensive and enlightening studies.
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Affiliation(s)
- Matthew A Firth
- Department of Pathobiology, University of Guelph, Guelph, ON, Canada NIG 2W1
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Abstract
Various pre- and postnatal risk factors, which act additively or synergistically induce an injurious inflammatory response in the airways and the pulmonary interstitium of preterm infants with bronchopulmonary dysplasia. This inflammatory response is characterized by an accumulation of neutrophils and macrophages as well as an arsenal of proinflammatory mediators that affect the endothelium and alveolar-capillary integrity. Besides proinflammatory cytokines and toxic oxygen radicals, lipid mediators as well as potent proteases may be responsible for acute lung injury. There is increasing evidence that an imbalance between pro- and anti-inflammatory factors, which should protect the alveoli and lung tissue, are key features in the pathogenesis of bronchopulmonary dysplasia. In addition, a subnormal generation of growth factors may affect alveolarization and vascular development in preterm infants with bronchopulmonary dysplasia. In this condensed review article, the current concepts on the possible role of inflammation in the evolution of bronchopulmonary dysplasia will be summarized.
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Affiliation(s)
- C P Speer
- Department of Pediatrics, University Children's Hospital, Würzburg, Germany.
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Zhang H, Gao G, Clayburne G, Schumacher HR. Elimination of rheumatoid synovium in situ using a Fas ligand 'gene scalpel'. Arthritis Res Ther 2005; 7:R1235-43. [PMID: 16277676 PMCID: PMC1297566 DOI: 10.1186/ar1811] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 07/29/2005] [Accepted: 08/03/2005] [Indexed: 11/10/2022] Open
Abstract
Surgical synovectomy to remove the inflammatory synovium can temporarily ameliorate rheumatoid inflammation and delay the progress of joint destruction. An efficient medically induced programmed cell death (apoptosis) in the rheumatoid synovium might play a role similar to synovectomy but without surgical tissue damage. Gene transfer of Fas ligand (FasL) has increased the frequency of apoptotic cells in mouse and rabbit arthritic synovium. In this study, we investigated whether repeated FasL gene transfer could remove human inflammatory synovial tissue in situ and function as a molecular synovectomy. Briefly, specimens of human synovium from joint replacement surgeries and synovectomies of rheumatoid arthritis (RA) patients were grafted subcutaneously into male C.B-17 severe combined immunodeficiency (SCID) mice. Injections of a recombinant FasL adenovirus (Ad-FasL) into the grafted synovial tissue at the dosage of 10(11) particles per mouse were performed every two weeks. Three days after the fifth virus injection, the mice were euthanized by CO2 inhalation and the human synovial tissues were collected, weighed and further examined. Compared to the control adenovirus-LacZ (Ad-LacZ) and phosphate buffered saline (PBS) injected RA synovium, the Ad-FasL injected RA synovium was dramatically reduced in size and weight (P < 0.005). The number of both synoviocytes & mononuclear cells was significantly reduced. Interestingly, an approximate 15-fold increased frequency of apoptotic cells was observed in RA synovium three days after Ad-FasL injection, compared with control tissues. In summary, our in vivo investigation of gene transfer to human synovium in SCID mice suggests that repeated intra-articular gene transfer of an apoptosis inducer, such as FasL, may function as a 'gene scalpel' for molecular synovectomy to arrest inflammatory synovium at an early stage of RA.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Apoptosis/genetics
- Arthritis, Rheumatoid/pathology
- Arthritis, Rheumatoid/therapy
- Cartilage, Articular/metabolism
- Cartilage, Articular/pathology
- Cartilage, Articular/transplantation
- Cell Count
- Disease Models, Animal
- Fas Ligand Protein
- Gene Transfer Techniques
- Gene Transfer, Horizontal
- Genetic Therapy
- Humans
- In Situ Nick-End Labeling
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Mice, SCID
- RNA, Messenger/metabolism
- Specific Pathogen-Free Organisms
- Synovial Membrane/metabolism
- Synovial Membrane/pathology
- Synovial Membrane/transplantation
- Transplantation, Heterologous
- Tumor Necrosis Factors/genetics
- Tumor Necrosis Factors/metabolism
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Affiliation(s)
- Haidi Zhang
- Division of Pharmaceutics and Industry Pharmacy, School of Pharmacy, Long Island University, Brooklyn, NY, USA
| | - Guangping Gao
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gilda Clayburne
- Veterans Affairs Medical Center in Philadelphia, Philadelphia, PA, USA
| | - H Ralph Schumacher
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Veterans Affairs Medical Center in Philadelphia, Philadelphia, PA, USA
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