Protein FOG at the interface between G streptococci and human host defence lines

Group G streptococci (GGS) may be of four different species and may infect humans and also animals. S. dysgalactiae equisimilis most commonly cause human GGS infections. These bacteria are part of the normal flora, but can cause pharyngitis, erysipelas and impetigo. In the immunocompromised host severe conditions, such as sepsis and necrotising fasciitis, may develop. In this thesis the interactions between GGS and various parts of human defence lines are investigated. A novel M protein from GGS, denoted FOG, was isolated, recombinantly expressed, and purified. FOG-positive strains survive in human whole blood wheras a FOG-negative strain did not. Addition of soluble FOG, but not protein G, leads to restoration of survival of the FOG-negative strain. Intact protein FOG mediated aggregation of neutrophils in the presence of fibrinogen which disabled these cells in excerting antibacterial activities. In vitro and in vivo, protein FOG interacts with collagen I, an abundant extracellular matrix protein of human skin. As streptococcal skin infections often preceed invasive disease, the FOG mediated binding to collagen is important and may be the first step of infection. A FOG-positive strain exhibited adhesional advantages compared to a FOG-negative strain. FOG, like protein G, recruits IgG from human plasma in a non-immune fashion. C1q, initiator of the classical pathway of complement, binds exclusively to the IgG bound via FOG but not to the IgG bound via protein G. IgG opsonisation via FOG but not via protein G led to an O2- production by neutrophils. FOG is released from the bacterial surface into the growth medium of bacterial early stationary growth phase and also by neutrophil elastase. Like M1, an M protein of GAS, FOG binds to monocytes and triggers secretion of the chemokines MIG (CXCL9) and IL-8 (CXCL-8). GGS are less susceptible than GAS, to antimicrobial effects of MIG in physiological NaCl concentrations corresponding to that of sweat and plasma but not of saliva, and also to these NaCl concentrations alone

Protein FOG - a streptococcal inhibitor of neutrophil function.

Several strains of group G streptococci (GGS) form aggregates when grown in vitro. Aggregating strains interact with fibrinogen, and this study reports the isolation of a novel self-associating and fibrinogen-binding protein of GGS, denoted protein FOG. Sequencing of the fog gene revealed structural similarity with M proteins of both GGS and group A streptococci (GAS). Analogous to GAS, GGS were found to multiply in human blood. All strains of GGS express protein G, a protein known to interact with the constant region of immunoglobulin G and albumin. Surprisingly, a clinical isolate expressing protein G, but lacking protein FOG, was killed in human whole blood; however, the addition of intact soluble protein FOG restored the ability of the bacteria to survive and multiply in human blood. This is believed to be the first report of a soluble M-like protein salvaging an M-negative strain from being killed. The antibactericidal property of protein FOG is dependent on its fibrinogen-binding activity. Thus, in plasma, FOG precipitates fibrinogen, and when added to whole blood, protein FOG triggers the formation of visible aggregates comprising fibrinogen and neutrophils that are disabled in their killing of the bacteria. Moreover, the results emphasize the importance of an intact FOG molecule, as presented on the bacterial surface, for full protective effect

A review on electrospun magnetic nanomaterials:methods, properties and applications

Magnetic materials display attractive properties for a wide range of applications. More recently, interest has turned to significantly enhancing their behaviour for advanced technologies, by exploiting the remarkable advantages that nanoscale materials offer over their bulk counterparts. Electrospinning is a high-throughput method that can continuously produce nanoscale fibres, providing a versatile way to prepare novel magnetic nanomaterials. This article reviews 20 years of magnetic nanomaterials fabricated via electrospinning and introduces their two primary production methods: electrospinning polymer-based magnetic fibres directly from solution and electrospinning fibrous templates for post-treatment. Continual advances in electrospinning have enabled access to a variety of morphologies, which has led to magnetic materials having desirable flexibility, anisotropy and high specific surface area. Post-treatment methods, such as surface deposition, carbonization and calcination, further improve or even create unique magnetic properties in the materials. This renders them useful in broad ranging applications, including electromagnetic interference shielding (EMS), magnetic separation, tissue engineering scaffolding, hyperthermia treatment, drug delivery, nanogenerators and data storage. The processing methods of electrospun magnetic nanofibres, their properties and related applications are discussed throughout this review. Key areas for future research have been highlighted with the aim of stimulating advances in the development of electrospun magnetic nanomaterials for a wide range of applications

Neural plasticity and proliferation in the generation of antidepressant effects: hippocampal implication

It is widely accepted that changes underlying depression and antidepressant-like effects involve not only alterations in the levels of neurotransmitters as monoamines and their receptors in the brain, but also structural and functional changes far beyond. During the last two decades, emerging theories are providing new explanations about the neurobiology of depression and the mechanism of action of antidepressant strategies based on cellular changes at the CNS level. The neurotrophic/plasticity hypothesis of depression, proposed more than a decade ago, is now supported by multiple basic and clinical studies focused on the role of intracellular-signalling cascades that govern neural proliferation and plasticity. Herein, we review the state-of-the-art of the changes in these signalling pathways which appear to underlie both depressive disorders and antidepressant actions. We will especially focus on the hippocampal cellularity and plasticity modulation by serotonin, trophic factors as brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF) through intracellular signalling pathways-cAMP, Wnt/ β -catenin, and mTOR. Connecting the classic monoaminergic hypothesis with proliferation/neuroplasticity-related evidence is an appealing and comprehensive attempt for improving our knowledge about the neurobiological events leading to depression and associated to antidepressant therapies

SpeB of Streptococcus pyogenes Differentially Modulates Antibacterial and Receptor Activating Properties of Human Chemokines

BACKGROUND: CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11, are antibacterial for Streptococcus pyogenes. METHODOLOGY/PRINCIPAL FINDINGS: SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/CXCL10, I-TAC/CXCL11, PF4/CXCL4, GROalpha/CXCL1, GRObeta/CXCL2, GROgamma/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/CXCL12, BCA-1/CXCL13, BRAK/CXCL14, SRPSOX/CXCL16, MIP-3alpha/CCL20, Lymphotactin/XCL1, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/CXCL16 and MIP-3alpha/CCL20, and releases a 6 kDa CXCL9 fragment. CXCL10 and CXCL11 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity. CONCLUSIONS/SIGNIFICANCE: SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium

Age-dependent alterations in the inflammatory response to pulmonary challenge

The aging lung is increasingly susceptible to infectious disease. Changes in pulmonary physiology and function are common in older populations, and in those older than 60 years, pneumonia is the major cause of infectious death. Understanding age-related changes in the innate and adaptive immune systems, and how they affect both pulmonary and systemic responses to pulmonary challenge are critical to the development of novel therapeutic strategies for the treatment of the elderly patient. In this observational study, we examined age-associated differences in inflammatory responses to pulmonary challenge with cell wall components from Gram-positive bacteria. Thus, male Sprague-Dawley rats, aged 6 months or greater than 18 months (approximating humans of 20 and 55-65 years), were challenged, intratracheally, with lipoteichoic acid and peptidoglycan. Cellular and cytokine evaluations were performed on both bronchoalveolar lavage fluid (BAL) and plasma, 24 h post-challenge. The plasma concentration of free thyroxine, a marker of severity in non-thyroidal illness, was also evaluated. The older animals had an increased chemotactic gradient in favor of the airspaces, which was associated with a greater accumulation of neutrophils and protein. Furthermore, macrophage migration inhibitory factor (MIF), an inflammatory mediator and putative biomarker in acute lung injury, was increased in both the plasma and BAL of the older, but not young animals. Conversely, plasma free thyroxine, a natural inhibitor of MIF, was decreased in the older animals. These findings identify age-associated inflammatory/metabolic changes following pulmonary challenge that it may be possible to manipulate to improve outcome in the older, critically ill patient

The PanCareSurFup consortium:research and guidelines to improve lives for survivors of childhood cancer

Background: Second malignant neoplasms and cardiotoxicity are among the most serious and frequent adverse health outcomes experienced by childhood and adolescent cancer survivors (CCSs) and contribute significantly to their increased risk of premature mortality. Owing to differences in health-care systems, language and culture across the continent, Europe has had limited success in establishing multi-country collaborations needed to assemble the numbers of survivors required to clarify the health issues arising after successful cancer treatment. PanCareSurFup (PCSF) is the first pan-European project to evaluate some of the serious long-term health risks faced by survivors. This article sets out the overall rationale, methods and preliminary results of PCSF. Methods: The PCSF consortium pooled data from 13 cancer registries and hospitals in 12 European countries to evaluate subsequent primary malignancies, cardiac disease and late mortality in survivors diagnosed between ages 0 and 20 years. In addition, PCSF integrated radiation dosimetry to sites of second malignancies and to the heart, developed evidence-based guidelines for long-term care and for transition services, and disseminated results to survivors and the public. Results: We identified 115,596 individuals diagnosed with cancer, of whom 83,333 were 5-year survivors and diagnosed from 1940 to 2011. This single data set forms the basis for cohort analyses of subsequent malignancies, cardiac disease and late mortality and case–control studies of subsequent malignancies and cardiac disease in 5-year survivors. Conclusions: PCSF delivered specific estimates of risk and comprehensive guidelines to help survivors and care-givers. The expected benefit is to provide every European CCS with improved access to care and better long-term health

Risk of Subsequent Bone Cancers Among 69 460 Five-Year Survivors of Childhood and Adolescent Cancer in Europe

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesINTRODUCTION: We investigate the risks of subsequent primary bone cancers after childhood and adolescent cancer in 12 European countries. For the first time, we satisfactorily address the risks beyond 40 years from diagnosis and beyond 40 years of age among all survivors. METHODS: This largest-ever assembled cohort comprises 69 460 five-year survivors of cancer diagnosed before age 20 years. Standardized incidence ratios, absolute excess risks, and multivariable-adjusted relative risks and relative excess risks were calculated. All statistical tests were two-sided. RESULTS: Overall, survivors were 21.65 times (95% confidence interval = 18.97 to 24.60 times) more likely to be diagnosed with a subsequent primary bone cancer than expected from the general population. The greatest excess numbers of bone cancers were observed after retinoblastoma, bone sarcoma, and soft tissue sarcoma. The excess number of bone cancers declined linearly with both years since diagnosis and attained age (all P < .05). Beyond 40 years from diagnosis and age 40 years, there were at most 0.45 excess bone cancers among all survivors per 10 000 person-years at risk; beyond 30 years from diagnosis and age 30 years, there were at most 5.02 excess bone cancers after each of retinoblastoma, bone sarcoma, and soft tissue sarcoma, per 10 000 person-years at risk. CONCLUSIONS: For all survivors combined and the cancer groups with the greatest excess number of bone cancers, the excess numbers observed declined with both age and years from diagnosis. These results provide novel, reliable, and unbiased information about risks and risk factors among long-term survivors of childhood and adolescent cancer.European Union Italian Association for Cancer Research Compagnia San Paolo Fondo Chiara Rama OLUS Swedish Childhood Cancer Foundation Norwegian Childhood Cancer Foundation La Ligue Nationale Contre le Cancer Agence Nationale pour la Recherche Scientifique Institut National du Cancer Fondation Pfizer pour la sante de l'enfant et de l'adolescent Slovenian Research Agency Swiss Paediatric Oncology Group Swiss Cancer League Swiss Cancer Research Foundation Swiss National Science Foundation Dutch Cancer Society European Unio

Risk of Soft-Tissue Sarcoma Among 69 460 Five-Year Survivors of Childhood Cancer in Europe

Childhood cancer survivors are at risk of subsequent primary soft-tissue sarcomas (STS), but the risks of specific STS histological subtypes are unknown. We quantified the risk of STS histological subtypes after specific types of childhood cancer.\nWe pooled data from 13 European cohorts, yielding a cohort of 69 460 five-year survivors of childhood cancer. Standardized incidence ratios (SIRs) and absolute excess risks (AERs) were calculated.Overall, 301 STS developed compared with 19 expected (SIR = 15.7, 95% confidence interval [CI] = 14.0 to 17.6). The highest standardized incidence ratios were for malignant peripheral nerve sheath tumors (MPNST; SIR = 40.6, 95% CI = 29.6 to 54.3), leiomyosarcomas (SIR = 29.9, 95% CI = 23.7 to 37.2), and fibromatous neoplasms (SIR = 12.3, 95% CI = 9.3 to 16.0). SIRs for MPNST were highest following central nervous system tumors (SIR = 80.5, 95% CI = 48.4 to 125.7), Hodgkin lymphoma (SIR = 81.3, 95% CI = 35.1 to 160.1), and Wilms tumor (SIR = 76.0, 95% CI = 27.9 to 165.4). Standardized incidence ratios for leiomyosarcoma were highest following retinoblastoma (SIR = 342.9, 95% CI = 245.0 to 466.9) and Wilms tumor (SIR = 74.2, 95% CI = 37.1 to 132.8). AERs for all STS subtypes were generally low at all years from diagnosis (AER < 1 per 10 000 person-years), except for leiomyosarcoma following retinoblastoma, for which the AER reached 52.7 (95% CI = 20.0 to 85.5) per 10 000 person-years among patients who had survived at least 45 years from diagnosis of retinoblastoma.\nFor the first time, we provide risk estimates of specific STS subtypes following childhood cancers and give evidence that risks of MPNSTs, leiomyosarcomas, and fibromatous neoplasms are particularly increased. While the multiplicative excess risks relative to the general population are substantial, the absolute excess risk of developing any STS subtype is low, except for leiomyosarcoma after retinoblastoma. These results are likely to be informative for both survivors and health care providers.</div