Role of the cystic fibrosis transmembrane conductance regulator in innate immunity to Pseudomonas aeruginosa infections

Evidence for intracellular Pseudomonas aeruginosa

Pseudomonas aeruginosa is a significant cause of global morbidity and mortality. Although it is often regarded as an extracellular pathogen toward human cells, numerous investigations report its ability to survive and replicate within host cells, and additional studies demonstrate specific mechanisms enabling it to adopt an intracellular lifestyle. This ability of P. aeruginosa remains less well-investigated than that of other intracellular bacteria, although it is currently gaining attention. If intracellular bacteria are not killed after entering host cells, they may instead receive protection from immune recognition and experience reduced exposure to antibiotic therapy, among additional potential advantages shared with other facultative intracellular pathogens. For this review, we compiled studies that observe intracellular P. aeruginosa across strains, cell types, and experimental systems in vitro, as well as contextualize these findings with the few studies that report similar observations in vivo. We also seek to address key findings that drove the perception that P. aeruginosa remains extracellular in order to reconcile what is currently understood about intracellular pathogenesis and highlight open questions regarding its contribution to disease.

Interferon-independent processes constrain measles virus cell-to-cell spread in primary human airway epithelial cells

Amplification of measles virus (MeV) in human airway epithelia may contribute to its extremely high contagious nature. We use well-differentiated primary cultures of human airway epithelial cells (HAE) to model ex vivo how MeV spreads in human airways. In HAE, MeV spreads cell-to-cell for 3-5 days, but then, infectious center growth is arrested. What stops MeV spread in HAE is not understood, but interferon (IFN) is known to slow MeV spread in other in vitro and in vivo models. Here, we assessed the role of type I and type III IFN in arresting MeV spread in HAE. The addition of IFN-β or IFN-λ1 to the medium of infected HAE slowed MeV infectious center growth, but when IFN receptor signaling was blocked, infectious center size was not affected. In contrast, blocking type-I IFN receptor signaling enhanced respiratory syncytial virus spread. HAE were also infected with MeV mutants defective for the V protein. The V protein has been demonstrated to interact with both MDA5 and STAT2 to inhibit activation of innate immunity; however, innate immune reactions were unexpectedly muted against the V-defective MeV in HAE. Minimal innate immunity activation was confirmed by deep sequencing, quantitative RT-PCR, and single-cell RNA-seq analyses of the transcription of IFN and IFN-stimulated genes. We conclude that in HAE, IFN-signaling can contribute to slowing infectious center growth; however, IFN-independent processes are most important for limiting cell-to-cell spread. IMPORTANCE Fundamental biological questions remain about the highly contagious measles virus (MeV). MeV amplifies within airway epithelial cells before spreading to the next host. This final step likely contributes to the ability of MeV to spread host-to-host. Over the course of 3-5 days post-infection of airway epithelial cells, MeV spreads directly cell-to-cell and forms infectious centers. Infectious center formation is unique to MeV. In this study, we show that interferon (IFN) signaling does not explain why MeV cell-to-cell spread is ultimately impeded within the cell layer. The ability of MeV to spread cell-to-cell in airway cells without appreciable IFN induction may contribute to its highly contagious nature. This study contributes to the understanding of a significant global health concern by demonstrating that infectious center formation occurs independent of the simplest explanation for limiting viral transmission within a host.

Respiratory Infection and Inflammation in Cystic Fibrosis: A Dynamic Interplay among the Host, Microbes, and Environment for the Ages

The interplay between airway inflammation and infection is now recognized as a major factor in the pathobiology in cystic fibrosis (CF). A proinflammatory environment is seen throughout the CF airway resulting in classic marked and enduring neutrophilic infiltrations, irreversibly damaging the lung. Although this is seen to occur early, independent of infection, respiratory microbes arising at different timepoints in life and the world environment perpetuate this hyperinflammatory state. Several selective pressures have allowed for the CF gene to persist until today despite an early mortality. Comprehensive care systems, which have been a cornerstone of therapy for the past few decades, are now revolutionized by CF transmembrane conductance regulator (CTFR) modulators. The effects of these small-molecule agents cannot be overstated and can be seen as early as in utero. For an understanding of the future, this review looks into CF studies spanning the historical and present period.

Phages and Nanotechnology: New Insights against Multidrug-Resistant Bacteria

Bacterial infections are a major threat to the human healthcare system worldwide, as antibiotics are becoming less effective due to the emergence of multidrug-resistant strains. Therefore, there is a need to explore nontraditional antimicrobial alternatives to support rapid interventions and combat the spread of pathogenic bacteria. New nonantibiotic approaches are being developed, many of them at the interface of physics, nanotechnology, and microbiology. While physical factors (e.g., pressure, temperature, and ultraviolet light) are typically used in the sterilization process, nanoparticles and phages (bacterial viruses) are also applied to combat pathogenic bacteria. Particularly, phage-based therapies are rising due to the unparalleled specificity and high bactericidal activity of phages. Despite the success of phages mostly as compassionate use in clinical cases, some drawbacks need to be addressed, mainly related to their stability, bioavailability, and systemic administration. Combining phages with nanoparticles can improve their performance in vivo. Thus, the combination of nanotechnology and phages might provide tools for the rapid and accurate detection of bacteria in biological samples (diagnosis and typing), and the development of antimicrobials that combine the selectivity of phages with the efficacy of targeted therapy, such as photothermal ablation or photodynamic therapies. In this review, we aim to provide an overview of how phage-based nanotechnology represents a step forward in the fight against multidrug-resistant bacteria.

SARS-CoV-2 nucleocapsid protein triggers hyperinflammation via protein-protein interaction-mediated intracellular Cl- accumulation in respiratory epithelium

SARS-CoV-2, the culprit pathogen of COVID-19, elicits prominent immune responses and cytokine storms. Intracellular Cl⁻ is a crucial regulator of host defense, whereas the role of Cl⁻ signaling pathway in modulating pulmonary inflammation associated with SARS-CoV-2 infection remains unclear. By using human respiratory epithelial cell lines, primary cultured human airway epithelial cells, and murine models of viral structural protein stimulation and SARS-CoV-2 direct challenge, we demonstrated that SARS-CoV-2 nucleocapsid (N) protein could interact with Smad3, which downregulated cystic fibrosis transmembrane conductance regulator (CFTR) expression via microRNA-145. The intracellular Cl⁻ concentration ([Cl⁻]_i) was raised, resulting in phosphorylation of serum glucocorticoid regulated kinase 1 (SGK1) and robust inflammatory responses. Inhibition or knockout of SGK1 abrogated the N protein-elicited airway inflammation. Moreover, N protein promoted a sustained elevation of [Cl⁻]_i by depleting intracellular cAMP via upregulation of phosphodiesterase 4 (PDE4). Rolipram, a selective PDE4 inhibitor, countered airway inflammation by reducing [Cl⁻]_i. Our findings suggested that Cl⁻ acted as the crucial pathological second messenger mediating the inflammatory responses after SARS-CoV-2 infection. Targeting the Cl⁻ signaling pathway might be a novel therapeutic strategy for COVID-19.

Genetics of cystic fibrosis: Basics

Cystic fibrosis (CF) is an autosomal recessive genetic disorder whose responsible gene - the CFTR gene - was discovered 30 years ago by a positional cloning strategy. This gene, which encodes a chloride channel, contains more than 2,000 mutations including a major one (p.Phe508del). This discovery has led to considerable progress in the understanding of the pathophysiology of CF as well as in the management of patients and their families. It has also paved the way for the development of specific therapies for the disease. From an epidemiological point of view, the incidence of CF, which shows loco-regional variations, is now estimated at 1/4,700 live births in France. The face of CF has dramatically changed over the past decades: CF has gradually become a disease of the adult with, today, more than 50% of the patients being 18 years old or more and a median predicted survival age that exceeds 45 years. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

The importance of intracellular bacterial biofilm in infectious diseases

Various bacterial species, previously known as extracellular pathogens, can reside inside different host cells by adapting to intracellular modes by forming microbial aggregates with similar characteristics to bacterial biofilms. Additionally, bacterial invasion of human cells leads to failure in antibiotic therapy, as most conventional anti-bacterial agents cannot reach intracellular biofilm in normal concentrations. Various studies have shown that bacteria such as uropathogenic Escherichia coli, Pseudomonas aeruginosa, Borrelia burgdorferi,Moraxella catarrhalis, non-typeable Haemophilus influenzae, Streptococcus pneumonia, and group A Streptococci produce biofilm-like structures within the host cells. For the first time in this review, we will describe and discuss the new information about intracellular bacterial biofilm formation and its importance in bacterial infectious diseases.

Structural and functional diversity of neutrophil glycosylation in innate immunity and related disorders

The granulated neutrophils are abundant innate immune cells that utilize bioactive glycoproteins packed in cytosolic granules to fight pathogenic infections, but the neutrophil glycobiology remains poorly understood. Facilitated by technological advances in glycoimmunology, systems glycobiology and glycoanalytics, a considerable body of literature reporting on novel aspects of neutrophil glycosylation has accumulated. Herein, we summarize the building knowledge of the structural and functional diversity displayed by N- and O-linked glycoproteins spatiotemporally expressed and sequentially brought-into-action across the diverse neutrophil life stages during bone marrow maturation, movements to, from and within the blood circulation and microbicidal processes at the inflammatory sites in peripheral tissues. It transpires that neutrophils abundantly decorate their granule glycoproteins including neutrophil elastase, myeloperoxidase and cathepsin G with peculiar glyco-signatures not commonly reported in other areas of human glycobiology such as hyper-truncated chitobiose core- and paucimannosidic-type N-glycans and monoantennary complex-type N-glycans. Sialyl Lewis^x, Lewis^x, poly-N-acetyllactosamine extensions and core 1-/2-type O-glycans are also common neutrophil glyco-signatures. Granule-specific glycosylation is another fascinating yet not fully understood feature of neutrophils. Recent literature suggests that unconventional biosynthetic pathways and functions underpin these prominent neutrophil-associated glyco-phenotypes. The impact of glycosylation on key neutrophil effector functions including extravasation, degranulation, phagocytosis and formation of neutrophil extracellular traps during normal physiological conditions and in innate immune-related diseases is discussed. We also highlight new technologies that are expected to further advance neutrophil glycobiology and briefly discuss the untapped diagnostic and therapeutic potential of neutrophil glycosylation that could open avenues to combat the increasingly prevalent innate immune disorders.

Novel Anti-Inflammatory Approaches for Cystic Fibrosis Lung Disease: Identification of Molecular Targets and Design of Innovative Therapies

Cystic fibrosis (CF) is the most common genetic disorder among Caucasians, estimated to affect more than 70,000 people in the world. Severe and persistent bronchial inflammation and chronic bacterial infection, along with airway mucus obstruction, are hallmarks of CF lung disease and participate in its progression. Anti-inflammatory therapies are, therefore, of particular interest for CF lung disease. Furthermore, a better understanding of the molecular mechanisms involved in airway infection and inflammation in CF has led to the development of new therapeutic approaches that are currently under evaluation by clinical trials. These new strategies dedicated to CF inflammation are designed to treat different dysregulated aspects such as oxidative stress, cytokine secretion, and the targeting of dysregulated pathways. In this review, we summarize the current understanding of the cellular and molecular mechanisms that contribute to abnormal lung inflammation in CF, as well as the new anti-inflammatory strategies proposed to CF patients by exploring novel molecular targets and novel drug approaches.

Staphylococcus aureus in chronic rhinosinusitis: the effect on the epithelial chloride channel (cystic fibrosis transmembrane conductance regulator, CFTR) and the epithelial sodium channel (ENaC) physiology

Background: Chronic rhinosinusitis (CRS) is an inflammatory disease of the nose and the paranasal sinuses, often associated with an infection by Staphylococcus aureus (S. aureus). Disturbance in the function of ion channels is regarded as an etiological factor for pathogenesis of CRS. Aims: The study aims to measure the mRNA expression of the ENaC and CFTR ion channels in nasal epithelial cells (NECs) and to investigate the effect of both the budesonide and S. aureus on these ion channels. Materials and method: NECs biopsies obtained from healthy volunteers and patients with CRS. NECs were infected with S. aureus strains and/or budesonide to study the mRNA expression levels of the ENaC and CFTR ion channels. Results: The mRNA expression level of CFTR was increased while that of ENaC was decreased. S. aureus infection and budesonide treatment induced a significant modulation of ENaC and CFTR ion channels expression. Conclusion: The CFTR and ENaC ion channel physiology are of importance in the pathogenesis of CRS. Exposure to S. aureus infection and treatment with budesonide modulated the mRNA expression of CFTR and ENaC ion channels. Significance: Better understanding of the pathophysiology of CRS.

Spleen Tyrosine Kinase as a Target Therapy for Pseudomonas aeruginosa Infection

Spleen tyrosine kinase (SYK) is a nonreceptor tyrosine kinase which associates directly with extracellular receptors, and is critically involved in signal transduction pathways in a variety of cell types for the regulation of cellular responses. SYK is expressed ubiquitously in immune and nonimmune cells, and has a much wider biological role than previously recognized. Several studies have highlighted SYK as a key player in the pathogenesis of a multitude of diseases. Pseudomonas aeruginosa is an opportunistic gram-negative pathogen, which is responsible for systemic infections in immunocompromised individuals, accounting for a major cause of severe chronic lung infection in cystic fibrosis patients and subsequently resulting in a progressive deterioration of lung function. Inhibition of SYK activity has been explored as a therapeutic option in several allergic disorders, autoimmune diseases, and hematological malignancies. This review focuses on SYK as a therapeutic target, and describes the possibility of how current knowledge could be translated for therapeutic purposes to regulate the immune response to the opportunistic pathogen P. aeruginosa.

Bacterial-Host Interactions: Physiology and Pathophysiology of Respiratory Infection

It has long been thought that respiratory infections are the direct result of acquisition of pathogenic viruses or bacteria, followed by their overgrowth, dissemination, and in some instances tissue invasion. In the last decades, it has become apparent that in contrast to this classical view, the majority of microorganisms associated with respiratory infections and inflammation are actually common members of the respiratory ecosystem and only in rare circumstances do they cause disease. This suggests that a complex interplay between host, environment, and properties of colonizing microorganisms together determines disease development and its severity. To understand the pathophysiological processes that underlie respiratory infectious diseases, it is therefore necessary to understand the host-bacterial interactions occurring at mucosal surfaces, along with the microbes inhabiting them, during symbiosis. Current knowledge regarding host-bacterial interactions during asymptomatic colonization will be discussed, including a plausible role for the human microbiome in maintaining a healthy state. With this as a starting point, we will discuss possible disruptive factors contributing to dysbiosis, which is likely to be a key trigger for pathobionts in the development and pathophysiology of respiratory diseases. Finally, from this renewed perspective, we will reflect on current and potential new approaches for treatment in the future.

NOD-like receptor(s) and host immune responses with Pseudomonas aeruginosa infection

INTRODUCTION

Molecular mechanisms underlying the interactions between Pseudomonas aeruginosa, the common opportunistic pathogen in cystic fibrosis individuals, and host induce a number of marked inflammatory responses and associate with complex therapeutic problems due to bacterial resistance to antibiotics in chronic stage of infection.

METHODS

Pseudomonas aeruginosa is recognized by number of pattern recognition receptors (PRRs); NOD-like receptors (NLRs) are a class of PRRs, which can recognize a variety of endogenous and exogenous ligands, thereby playing a critical role in innate immunity.

RESULTS

NLR activation initiates forming of a multi-protein complex called inflammasome that induces activation of caspase-1 and resulted in cleavage of pro-inflammatory cytokines interleukin (IL)-1β and IL-18. When the IL-1β is secreted excessively, this causes tissue damage and extensive inflammatory responses that are potentially hazardous for the host.

CONCLUSIONS

Recent evidence has laid out inflammasome-forming NLR far beyond inflammation. This review summarizes current knowledge regarding the various roles played by different NLRs and associated down-signals, either in recognition of P. aeruginosa or may be associated with such bacterial pathogen infection, which may relate to for the complexity of lung diseases caused by P. aeruginosa.

Elevated Mirc1/Mir17-92 cluster expression negatively regulates autophagy and CFTR (cystic fibrosis transmembrane conductance regulator) function in CF macrophages

Cystic fibrosis (CF) is a fatal, genetic disorder that critically affects the lungs and is directly caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in defective CFTR function. Macroautophagy/autophagy is a highly regulated biological process that provides energy during periods of stress and starvation. Autophagy clears pathogens and dysfunctional protein aggregates within macrophages. However, this process is impaired in CF patients and CF mice, as their macrophages exhibit limited autophagy activity. The study of microRNAs (Mirs), and other noncoding RNAs, continues to offer new therapeutic targets. The objective of this study was to elucidate the role of Mirs in dysregulated autophagy-related genes in CF macrophages, and then target them to restore this host-defense function and improve CFTR channel function. We identified the Mirc1/Mir17-92 cluster as a potential negative regulator of autophagy as CF macrophages exhibit decreased autophagy protein expression and increased cluster expression when compared to wild-type (WT) counterparts. The absence or reduced expression of the cluster increases autophagy protein expression, suggesting the canonical inverse relationship between Mirc1/Mir17-92 and autophagy gene expression. An in silico study for targets of Mirs that comprise the cluster suggested that the majority of the Mirs target autophagy mRNAs. Those targets were validated by luciferase assays. Notably, the ability of macrophages expressing mutant F508del CFTR to transport halide through their membranes is compromised and can be restored by downregulation of these inherently elevated Mirs, via restoration of autophagy. In vivo, downregulation of Mir17 and Mir20a partially restored autophagy expression and hence improved the clearance of Burkholderia cenocepacia. Thus, these data advance our understanding of mechanisms underlying the pathobiology of CF and provide a new therapeutic platform for restoring CFTR function and autophagy in patients with CF.

Partial Restoration of CFTR Function in cftr-Null Mice following Targeted Cell Replacement Therapy

Cystic fibrosis (CF) is a fatal recessive genetic disorder caused by a mutation in the gene encoding CF transmembrane conductance regulator (CFTR) protein. Alteration in CFTR leads to thick airway mucus and bacterial infection. Cell therapy has been proposed for CFTR restoration, but efficacy has been limited by low engraftment levels. In our previous studies, we have shown that using a pre-conditioning regimen in combination with optimization of cell number and time of delivery, we could obtain greater bone marrow cell (BMC) retention in the lung. Here, we found that optimized delivery of wild-type (WT) BMC contributed to apical CFTR expression in airway epithelium and restoration of select ceramide species and fatty acids in CFTR^-/- mice. Importantly, WT BMC delivery delayed Pseudomonas aeruginosa lung infection and increased survival of CFTR^-/- recipients. Only WT BMCs had a beneficial effect beyond 6 months, suggesting a dual mechanism of BMC benefit: a non-specific effect early after cell delivery, possibly due to the recruitment of macrophages and neutrophils, and a late beneficial effect dependent on long-term CFTR expression. Taken together, our results suggest that BMC can improve overall lung function and may have potential therapeutic benefit for the treatment of CF.

Role of IRE1α/XBP-1 in Cystic Fibrosis Airway Inflammation

Cystic fibrosis (CF) pulmonary disease is characterized by chronic airway infection and inflammation. The infectious and inflamed CF airway environment impacts on the innate defense of airway epithelia and airway macrophages. The CF airway milieu induces an adaptation in these cells characterized by increased basal inflammation and a robust inflammatory response to inflammatory mediators. Recent studies have indicated that these responses depend on activation of the unfolded protein response (UPR). This review discusses the contribution of airway epithelia and airway macrophages to CF airway inflammatory responses and specifically highlights the functional importance of the UPR pathway mediated by IRE1/XBP-1 in these processes. These findings suggest that targeting the IRE1/XBP-1 UPR pathway may be a therapeutic strategy for CF airway disease.

Cystic Fibrosis and Other Respiratory Diseases of Impaired Mucus Clearance

Exposed to a diverse array of potentially noxious agents, the respiratory tract is protected by a highly developed innate defense system. Physiologically regulated epithelial ion and water transport coordinated with mucin secretion, beating cilia, and cough results in continuous flow of fluid and mucus over airway surfaces toward the larynx. This cleansing action is the initial and perhaps most quantitatively important innate defense mechanism. Repeated lung infections and eventual respiratory insufficiency characteristic of human cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) illustrate the consequences of impaired mucus clearance. Altered mucus clearance likely contributes to the initiation, progression, and chronicity of other airway diseases characterized by inflammation and mucous secretory cell hyper/metaplasia that afflict millions worldwide, including chronic obstructive pulmonary disease (COPD). This review concisely discusses the pathophysiology of human diseases characterized by genetic defects that impair mucus clearance. It then explores animal models in which components of the mucus clearance system have been disrupted. These models firmly establish the importance of mucus clearance for respiratory health, and will help elucidate disease mechanisms and therapeutic strategies in CF, PCD and COPD.

Defective innate immunity and hyperinflammation in newborn cystic fibrosis transmembrane conductance regulator-knockout ferret lungs

Mucociliary clearance (MCC) and submucosal glands are major components of airway innate immunity that have impaired function in cystic fibrosis (CF). Although both of these defense systems develop postnatally in the ferret, the lungs of newborn ferrets remain sterile in the presence of a functioning cystic fibrosis transmembrane conductance regulator gene. We evaluated several components of airway innate immunity and inflammation in the early CF ferret lung. At birth, the rates of MCC did not differ between CF and non-CF animals, but the height of the airway surface liquid was significantly reduced in CF newborn ferrets. CF ferrets had impaired MCC after 7 days of age, despite normal rates of ciliogenesis. Only non-CF ferrets eradicated Pseudomonas directly introduced into the lung after birth, whereas both genotypes could eradicate Staphylococcus. CF bronchoalveolar lavage fluid (BALF) had significantly lower antimicrobial activity selectively against Pseudomonas than non-CF BALF, which was insensitive to changes in pH and bicarbonate. Liquid chromatography-tandem mass spectrometry and cytokine analysis of BALF from sterile Caesarean-sectioned and nonsterile naturally born animals demonstrated CF-associated disturbances in IL-8, TNF-α, and IL-β, and pathways that control immunity and inflammation, including the complement system, macrophage functions, mammalian target of rapamycin signaling, and eukaryotic initiation factor 2 signaling. Interestingly, during the birth transition, IL-8 was selectively induced in CF BALF, despite no genotypic difference in bacterial load shortly after birth. These results suggest that newborn CF ferrets have defects in both innate immunity and inflammatory signaling that may be important in the early onset and progression of lung disease in these animals.

Cholesteryl esters are elevated in the lipid fraction of bronchoalveolar lavage fluid collected from pediatric cystic fibrosis patients

Background

Host-derived lipids including cholesteryl esters (CEs) such as cholesteryl linoleate have emerged as important antibacterial effectors of innate immunity in the airways and cholesteryl linoleate has been found elevated in the context of inflammation. Cystic fibrosis (CF) patients suffer from chronic infection and severe inflammation in the airways. Here, we identified and quantified CEs in bronchoalveolar lavage fluid (BALF) from CF patients and non-CF disease controls, and tested whether CE concentrations are linked to the disease.

Materials and Methods

CEs in BALF from 6 pediatric subjects with CF and 7 pediatric subjects with non-CF chronic lung disease were quantified by mass spectral analysis using liquid chromatography coupled with tandem mass spectrometry and multiple reaction monitoring. BALFs were also examined for total lipid, total protein, albumin, and, as a marker for inflammation, human neutrophil peptide (HNP) 1–3 concentrations. Statistical analysis was conducted after log 10 transformation of the data.

Results

Total lipid/protein ratio was reduced in CF BALF (p = 0.018) but the concentrations of CEs, including cholesteryl linoleate, were elevated in the total lipid fraction in CF BALF compared to non-CF disease controls (p < 0.050). In addition, the concentrations of CEs and HNP1-3 correlated with one another (p < 0.050).

Conclusions

The data suggests that the lipid composition of BALF is altered in CF with less total lipid relative to protein but with increased CE concentrations in the lipid fraction, likely contributed by inflammation. Future longitudinal studies may reveal the suitability of CEs as a novel biomarker for CF disease activity which may provide new information on the lipid mediated pathophysiology of the disease.

Second-hand cigarette smoke impairs bacterial phagocytosis in macrophages by modulating CFTR dependent lipid-rafts

Introduction

First/Second-hand cigarette-smoke (FHS/SHS) exposure weakens immune defenses inducing chronic obstructive pulmonary disease (COPD) but the underlying mechanisms are not fully understood. Hence, we evaluated if SHS induced changes in membrane/lipid-raft (m-/r)-CFTR (cystic fibrosis transmembrane conductance regulator) expression/activity is a potential mechanism for impaired bacterial phagocytosis in COPD.

Methods

RAW264.7 murine macrophages were exposed to freshly prepared CS-extract (CSE) containing culture media and/or Pseudomonas-aeruginosa-PA01-GFP for phagocytosis (fluorescence-microscopy), bacterial survival (colony-forming-units-CFU), and immunoblotting assays. The CFTR-expression/activity and lipid-rafts were modulated by transient-transfection or inhibitors/inducers. Next, mice were exposed to acute/sub-chronic-SHS or room-air (5-days/3-weeks) and infected with PA01-GFP, followed by quantification of bacterial survival by CFU-assay.

Results

We investigated the effect of CSE treatment on RAW264.7 cells infected by PA01-GFP and observed that CSE treatment significantly (p<0.01) inhibits PA01-GFP phagocytosis as compared to the controls. We also verified this in murine model, exposed to acute/sub-chronic-SHS and found significant (p<0.05, p<0.02) increase in bacterial survival in the SHS-exposed lungs as compared to the room-air controls. Next, we examined the effect of impaired CFTR ion-channel-activity on PA01-GFP infection of RAW264.7 cells using CFTR172-inhibitor and found no significant change in phagocytosis. We also similarly evaluated the effect of a CFTR corrector-potentiator compound, VRT-532, and observed no significant rescue of CSE impaired PA01-GFP phagocytosis although it significantly (p<0.05) decreases CSE induced bacterial survival. Moreover, induction of CFTR expression in macrophages significantly (p<0.03) improves CSE impaired PA01-GFP phagocytosis as compared to the control. Next, we verified the link between m-/r-CFTR expression and phagocytosis using methyl-β-cyclodextran (CD), as it is known to deplete CFTR from membrane lipid-rafts. We observed that CD treatment significantly (p<0.01) inhibits bacterial phagocytosis in RAW264.7 cells and adding CSE further impairs phagocytosis suggesting synergistic effect on CFTR dependent lipid-rafts.

Conclusion

Our data suggest that SHS impairs bacterial phagocytosis by modulating CFTR dependent lipid-rafts.

Pseudomonas aeruginosa in cystic fibrosis patients with G551D-CFTR treated with ivacaftor

BACKGROUND

Ivacaftor improves outcomes in cystic fibrosis (CF) patients with the G551D mutation; however, effects on respiratory microbiology are largely unknown. This study examines changes in CF respiratory pathogens with ivacaftor and correlates them with baseline characteristics and clinical response.

METHODS

The G551D Observational Study enrolled a longitudinal observational cohort of US patients with CF aged 6 years and older with at least 1 copy of the G551D mutation. Results were linked with retrospective and prospective culture data in the US Cystic Fibrosis Foundation's National Patient Registry. Pseudomonas aeruginosa infection category in the year before and year after ivacaftor was compared and correlated with clinical findings.

RESULTS

Among 151 participants prescribed ivacaftor, 29% (26/89) who were culture positive for P. aeruginosa the year prior to ivacaftor use were culture negative the year following treatment; 88% (52/59) of those P. aeruginosa free remained uninfected. The odds of P. aeruginosa positivity in the year after ivacaftor compared with the year prior were reduced by 35% (odds ratio [OR], 0.65; P < .001). Ivacaftor was also associated with reduced odds of mucoid P. aeruginosa (OR, 0.77; P = .013) and Aspergillus (OR, 0.47; P = .039), but not Staphylococcus aureus or other common CF pathogens. Patients with intermittent culture positivity and higher forced expiratory volume in 1 second (FEV1) were most likely to turn culture negative. Reduction in P. aeruginosa was not associated with change in FEV1, body mass index, or hospitalizations.

CONCLUSIONS

Pseudomonas aeruginosa culture positivity was significantly reduced following ivacaftor treatment. Efficacious CFTR modulation may contribute to lower frequency of culture positivity for P. aeruginosa and other respiratory pathogens, particularly in patients with less established disease.

Decreased expression of HLA-DQ and HLA-DR on cells of the monocytic lineage in cystic fibrosis

We studied HLA class II molecules on blood monocyte subsets, blood dendritic cells, sputum macrophages, and monocyte-derived macrophages at the protein (flow cytometry) and mRNA level (RT-PCR) in adult patients with cystic fibrosis (CF) and healthy control subjects as putative contributors to the CF phenotype. In healthy donors, we found a high average HLA-DQ expression of 4.35 mean specific fluorescence intensity units (ΔMnI) on classical blood monocytes. In F508del homozygous CF patients, the average ΔMnI was low (1.80). Patients were divided into two groups, in which 14 of these patients had HLA-DQ expression above 2 ΔMnI (average 3.25 ΔMnI, CF-DQ(group1)) and 36 below (average 1.24 ΔMnI, CF-DQ(group2)). Also, the CD16-positive monocyte subset and blood dendritic cells showed much lower levels of HLA-DQ for the CF-DQ(group2) patients compared with healthy controls. In macrophages from sputum and derived from monocytes, in vitro HLA-DQ expression was dramatically decreased to background levels in CF-DQ(group2). MHC class II transcripts were reduced in CF with a sevenfold decrease in HLA-DQβ1 for CF-DQ(group2) patients. Higher levels of the inflammation marker CRP were associated with low HLA-DQ protein expression, and in vitro treatment with the inflammatory molecule lipopolysaccharide reduced HLA-DQ expression. Interferon γ (IFNγ) could overcome this effect in healthy donor cells while, in CF, the IFNγ-induced activation was impaired. Our data demonstrate a pronounced reduction of HLA-DQ expression in CF, which is associated with inflammation and a reduced response to IFNγ.

KEY MESSAGE

• CF patients show a reduced expression of MHCII molecules in monocytes and macrophages. • HLA-DQ and HLA-DR transcript levels are also reduced in CF patients. • CF patient C-reactive protein levels correlate with low HLA-DQ expression. • Reduced expression of MHC class II molecules appears to be linked to inflammation. • CF patients exhibit an impaired response to IFNgamma.

Pseudomonas aeruginosa biofilms: mechanisms of immune evasion

The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.

Impaired functions of macrophage from cystic fibrosis patients: CD11b, TLR-5 decrease and sCD14, inflammatory cytokines increase

BACKGROUND

Early in life, cystic fibrosis (CF) patients are infected with microorganisms. The role of macrophages has largely been underestimated in literature, whereas the focus being mostly on neutrophils and epithelial cells. Macrophages may however play a significant role in the initiating stages of this disease, via an inability to act as a suppressor cell. Yet macrophage dysfunction may be the first step in cascade of events leading to chronic inflammation/infection in CF. Moreover, reports have suggested that CFTR contribute to altered inflammatory response in CF by modification of normal macrophage functions.

OBJECTIVES

In order to highlight possible intrinsic macrophage defects due to impaired CFTR, we have studied inflammatory cytokines secretions, recognition of pathogens and phagocytosis in peripheral blood monocyte-derived macrophages from stable adult CF patients and healthy subjects (non-CF).

RESULTS

In CF macrophage supernatants, concentrations of sCD14, IL-1β, IL-6, TNF-α and IL-10 were strongly raised. Furthermore expression of CD11b and TLR-5 were sorely decreased on CF macrophages. Beside, no difference was observed for mCD14, CD16, CD64, TLR-4 and TLR1/TLR-2 expressions. Moreover, a strong inhibition of phagocytosis was observed for CF macrophages. Elsewhere CFTR inhibition in non-CF macrophages also led to alterations of phagocytosis function as well as CD11b expression.

CONCLUSIONS

Altogether, these findings demonstrate excessive inflammation in CF macrophages, characterized by overproduction of sCD14 and inflammatory cytokines, with decreased expression of CD11b and TLR-5, and impaired phagocytosis. This leads to altered clearance of pathogens and non-resolution of infection by CF macrophages, thereby inducing an exaggerated pro-inflammatory response.

Effects of Aspergillus fumigatus colonization on lung function in cystic fibrosis

PURPOSE OF REVIEW

Aspergillus fumigatus is frequently isolated from cystic fibrosis (CF) patients and is notorious for its role in the debilitating condition of allergic bronchopulmonary aspergillosis (ABPA). Although CF patients suffer from perpetual microorganism-related lung disease, it is unclear whether A. fumigatus colonization has a role in causing accelerated lung function decline and whether intervention is necessary.

RECENT FINDINGS

A. fumigatus morbidity appears to be related to cystic fibrosis transmembrane conductance regulator-dependant function of the innate immune system. A. fumigatus-colonized patients have a lower lung capacity, more frequent hospitalizations and more prominent radiological abnormalities than noncolonized patients. Treatment with antifungal agents can be of value but has several drawbacks and a direct effect on lung function is yet to be shown.

SUMMARY

A. fumigatus appears to have an important role in CF lung disease, not exclusive to the context of ABPA. However, a causal relationship still needs to be confirmed. Study observations and trends indicate a need to further elucidate the mechanisms of A. fumigatus interactions with the host innate immune system and its role in CF lung morbidity.

Host Defence against Bacterial Biofilms: “Mission Impossible”?

Bacteria living as biofilms have been recognised as the ultimate cause of persistent and destructive inflammatory processes. Biofilm formation is a well-organised, genetically-driven process, which is well characterised for numerous bacteria species. In contrast, the host response to bacterial biofilms is less well analysed, and there is the general believe that bacteria in biofilms escape recognition or eradication by the immune defence. In this review the host response to bacterial biofilms is discussed with particular focus on the role of neutrophils because these phagocytic cells are the first to infiltrate areas of bacterial infection, and because neutrophils are equipped with a wide arsenal of bactericidal and toxic entities. I come to the conclusion that bacterial biofilms are not inherently protected against the attack by neutrophils, but that control of biofilm formation is possible depending on a timely and sufficient host response.

Pseudomonas aeruginosa pili and flagella mediate distinct binding and signaling events at the apical and basolateral surface of airway epithelium

Pseudomonas aeruginosa, an important opportunistic pathogen of man, exploits numerous factors for initial attachment to the host, an event required to establish bacterial infection. In this paper, we rigorously explore the role of two major bacterial adhesins, type IV pili (Tfp) and flagella, in bacterial adherence to distinct host receptors at the apical (AP) and basolateral (BL) surfaces of polarized lung epithelial cells and induction of subsequent host signaling and pathogenic events. Using an isogenic mutant of P. aeruginosa that lacks flagella or utilizing beads coated with purified Tfp, we establish that Tfp are necessary and sufficient for maximal binding to host N-glycans at the AP surface of polarized epithelium. In contrast, experiments utilizing a P. aeruginosa isogenic mutant that lacks Tfp or using beads coated with purified flagella demonstrate that flagella are necessary and sufficient for maximal binding to heparan sulfate (HS) chains of heparan sulfate proteoglycans (HSPGs) at the BL surface of polarized epithelium. Using two different cell-free systems, we demonstrate that Tfp-coated beads show highest binding affinity to complex N-glycan chains coated onto plastic plates and preferentially aggregate with beads coated with N-glycans, but not with single sugars or HS. In contrast, flagella-coated beads bind to or aggregate preferentially with HS or HSPGs, but demonstrate little binding to N-glycans. We further show that Tfp-mediated binding to host N-glycans results in activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway and bacterial entry at the AP surface. At the BL surface, flagella-mediated binding to HS activates the epidermal growth factor receptor (EGFR), adaptor protein Shc, and PI3K/Akt, and induces bacterial entry. Remarkably, flagella-coated beads alone can activate EGFR and Shc. Together, this work provides new insights into the intricate interactions between P. aeruginosa and lung epithelium that may be potentially useful in the development of novel treatments for P. aeruginosa infections.

Non-typeable Haemophilus influenzae invasion and persistence in the human respiratory tract

Non-typeable Haemophilus influenzae (NTHI) is an opportunistic bacterial pathogen of the human respiratory tract and is a leading cause of respiratory infections in children and adults. NTHI is considered to be an extracellular pathogen, but has consistently been observed within and between human respiratory epithelial cells and macrophages, in vitro and ex vivo. Until recently, few studies have examined the internalization, trafficking, and fate of NTHI in host cells. It is important to clarify this interaction because of a possible correlation between intracellular NTHI and symptomatic infection, and because NTHI infections frequently persist and recur despite antibiotic therapy and the development of bactericidal antibodies, suggesting a possible intracellular state or reservoir for NTHI. How does NTHI enter host cells? Can NTHI survive intracellularly and, if so, for how long? Strides have been made in the identification of host receptors, signaling, endocytosis, and trafficking pathways involved in the entry and persistence of NTHI in the respiratory tract.

Dysfunctional CFTR alters the bactericidal activity of human macrophages against Pseudomonas aeruginosa

Chronic inflammation of the lung, as a consequence of persistent bacterial infections by several opportunistic pathogens represents the main cause of mortality and morbidity in cystic fibrosis (CF) patients. Mechanisms leading to increased susceptibility to bacterial infections in CF are not completely known, although the involvement of cystic fibrosis transmembrane conductance regulator (CFTR) in microbicidal functions of macrophages is emerging. Tissue macrophages differentiate in situ from infiltrating monocytes, additionally, mature macrophages from different tissues, although having a number of common activities, exhibit variation in some molecular and cellular functions. In order to highlight possible intrinsic macrophage defects due to CFTR dysfunction, we have focused our attention on in vitro differentiated macrophages from human peripheral blood monocytes. Here we report on the contribution of CFTR in the bactericidal activity against Pseudomonas aeruginosa of monocyte derived human macrophages. At first, by real time PCR, immunofluorescence and patch clamp recordings we demonstrated that CFTR is expressed and is mainly localized to surface plasma membranes of human monocyte derived macrophages (MDM) where it acts as a cAMP-dependent chloride channel. Next, we evaluated the bactericidal activity of P. aeruginosa infected macrophages from healthy donors and CF patients by antibiotic protection assays. Our results demonstrate that control and CF macrophages do not differ in the phagocytic activity when infected with P. aeruginosa. Rather, although a reduction of intracellular live bacteria was detected in both non-CF and CF cells, the percentage of surviving bacteria was significantly higher in CF cells. These findings further support the role of CFTR in the fundamental functions of innate immune cells including eradication of bacterial infections by macrophages.

Differential adaptation of microbial pathogens to airways of patients with cystic fibrosis and chronic obstructive pulmonary disease

Cystic fibrosis (CF), the most common autosomal recessive disorder in Caucasians, and chronic obstructive pulmonary disease (COPD), a disease of adults, are characterized by chronic lung inflammation, airflow obstruction and extensive tissue remodelling, which have a major impact on patients' morbidity and mortality. Airway inflammation is stimulated in CF by chronic bacterial infections and in COPD by environmental stimuli, particularly from smoking. Pseudomonas aeruginosa is the major bacterial pathogen in CF, while in COPD, Haemophilus influenzae is most frequently observed. Molecular studies indicate that during chronic pulmonary infection, P. aeruginosa clones genotypically and phenotypically adapt to the CF niche, resulting in a highly diverse bacterial community that is difficult to eradicate therapeutically. Pseudomonas aeruginosa clones from COPD patients remain within the airways only for limited time periods, do not adapt and are easily eradicated. However, in a subgroup of severely ill COPD patients, P. aeruginosa clones similar to those in CF persist. In this review, we will discuss the pathophysiology of lung disease in CF and COPD, the complex genotypic and phenotypic adaptation processes of the opportunistic bacterial pathogens and novel treatment options.

N-glycosylation augmentation of the cystic fibrosis epithelium improves Pseudomonas aeruginosa clearance

Chronic lung colonization with Pseudomonas aeruginosa is anticipated in cystic fibrosis (CF). Abnormal terminal glycosylation has been implicated as a candidate for this condition. We previously reported a down-regulation of mannose-6-phosphate isomerase (MPI) for core N-glycan production in the CFTR-defective human cell line (IB3). We found a 40% decrease in N-glycosylation of IB3 cells compared with CFTR-corrected human cell line (S9), along with a threefold-lower surface attachment of P. aeruginosa strain, PAO1. There was a twofold increase in intracellular bacteria in S9 cells compared with IB3 cells. After a 4-hour clearance period, intracellular bacteria in IB3 cells increased twofold. Comparatively, a twofold decrease in intracellular bacteria occurred in S9 cells. Gene augmentation in IB3 cells with hMPI or hCFTR reversed these IB3 deficiencies. Mannose-6-phosphate can be produced from external mannose independent of MPI, and correction in the IB3 clearance deficiencies was observed when cultured in mannose-rich medium. An in vivo model for P. aeruginosa colonization in the upper airways revealed an increased bacterial burden in the trachea and oropharynx of nontherapeutic CF mice compared with mice treated either with an intratracheal delivery adeno-associated viral vector 5 expressing murine MPI, or a hypermannose water diet. Finally, a modest lung inflammatory response was observed in CF mice, and was partially corrected by both treatments. Augmenting N-glycosylation to attenuate colonization of P. aeruginosa in CF airways reveals a new therapeutic avenue for a hallmark disease condition in CF.

Pseudomonas aeruginosa and the host pulmonary immune response

Pseudomonas aeruginosa is a highly adaptable, opportunistic pathogen that is commonly found in the environment. It can infect a number of sites in the body and disseminate. It can cause both acute and chronic pulmonary infection and the acuity of infection and accompanying inflammatory phenotype is determined, for the most part, by the host. Although P. aeruginosa has been a successful opportunist in the context of a number of different disease states, it has been best studied in the context of cystic fibrosis (CF). The adaptability of P. aeruginosa has enabled it to adjust quickly to the CF airway, transitioning from initial colonization to chronic infection. The organism quickly expresses virulence factors that allow it to circumvent some elements of the host immune response and, even more importantly, quickly develops antimicrobial resistance. In the case of CF, chronic infection resulting in progressive lung damage, coupled with antimicrobial resistance, becomes an increasingly important issue as individuals with CF live longer. It is for these reasons that both organism- and host-targeted immunotherapies are being increasingly explored.

Gene therapy for cystic fibrosis lung disease

Cystic fibrosis (CF) is characterised by respiratory and pancreatic deficiencies that stem from the loss of fully functional CFTR (CF transmembrane conductance regulator) at the membrane of epithelial cells. Current treatment modalities aim to delay the deterioration in lung function, Which is mostly responsible for the relatively short life expectancy of CF sufferers; however none have so far successfully dealt with the underlying molecular defect. Novel pharmacological approaches to ameliorate the lack of active CFTR in respiratory epithelial cells are beginning to address more of the pathophysiological defects caused by CFTR mutations. However, CFTR gene replacement by gene therapy remains the most likely option for addressing the basic defects, including ion transport and inflammatory functions of CFTR. In this chapter, We will review the latest preclinical and clinical advances in pharmacotherapy and gene therapy for CF lung disease.

Lymphocytic leiomyositis and myenteric ganglionitis are intrinsic features of cystic fibrosis: studies in distal intestinal obstruction syndrome and meconium ileus

BACKGROUND

Cystic fibrosis (CF) is a multisystem disorder intrinsically associated with inflammation of mucosal surfaces. Because inflammation can result in enteric neuromuscular dysfunction we hypothesized that terminal ileitis in patients with CF may predispose to distal ileal obstruction syndrome (DIOS).

METHODS AND PATIENTS

Full-thickness terminal ileal tissues from 6 children with CF and severe DIOS, 6 infants with complicated meconium ileus (MI), and 6 children with non-CF intestinal atresia were studied.

RESULTS

Lymphocyte-predominant mucosal and transmural ileal inflammation was present in 6 of 6 patients with DIOS. Lymphocytic ganglionitis was present in 4 of 6 although numbers of myenteric neurons were not decreased (5/5). Myocyte proteins were preserved (6/6). Mild submucosal fibrosis was common in DIOS (5/6) and transformation of submucosal fibroblasts to a myofibroblastic phenotype was noted in 4 of 6. Inflammatory changes were distinct from those described in fibrosing colonopathy. Antroduodenal manometry in an individual who had experienced MI/DIOS was consistent with a neuropathic pseudo-obstructive process. Submucosal or transmural lymphocyte predominant inflammation was also present in 6 of 6 infants with complicated MI, which, when coupled with submucosal myofibroblast proliferation (5/6), appeared highly predictive of CF rather than non-CF atresia. Histological findings at birth were similar, although milder, than those seen in DIOS, suggesting that these changes are a primary abnormality in CF.

CONCLUSIONS

Submucosal or transmural inflammation of the ileum is common in newborns with CF and MI and older children with DIOS. Severe recurrent DIOS should be investigated with seromuscular and mucosal biopsy of the ileum to seek a transmural ileitis potentially amenable to anti-inflammatory therapies.

Cystic fibrosis transmembrane conductance regulator and caveolin-1 regulate epithelial cell internalization of Pseudomonas aeruginosa

Patients with cystic fibrosis (CF) exhibit defective innate immunity and are susceptible to chronic lung infection with Pseudomonas aeruginosa. To investigate the molecular bases for the hypersusceptibility of CF patients to P. aeruginosa, we used the IB3-1 cell line with two defective CF transmembrane conductance regulator (CFTR) genes (DeltaF508/W1282X) to generate isogenic stable, clonal lung epithelial cells expressing wild-type (WT)-CFTR with an NH(2)-terminal green fluorescent protein (GFP) tag. GFP-CFTR exhibited posttranslational modification, subcellular localization, and anion transport function typical of WT-CFTR. P. aeruginosa internalization, a component of effective innate immunity, required functional CFTR and caveolin-1, as shown by: 1) direct correlation between GFP-CFTR expression levels and P. aeruginosa internalization; 2) enhanced P. aeruginosa internalization by aminoglycoside-induced read through of the CFTR W1282X allele in IB3-1 cells; 3) decreased P. aeruginosa internalization following siRNA knockdown of GFP-CFTR or caveolin-1; and 4) spatial association of P. aeruginosa with GFP-CFTR and caveolin-1 at the cell surface. P. aeruginosa internalization also required free lateral diffusion of GFP-CFTR, allowing for bacterial coclustering with GFP-CFTR and caveolin-1 at the plasma membrane. Thus efficient initiation of innate immunity to P. aeruginosa requires formation of an epithelial "internalization platform" involving both caveolin-1 and functional, laterally mobile CFTR.

Cystic fibrosis and innate immunity: how chloride channel mutations provoke lung disease

Innate immunity is essential for prevention of infection in vertebrates and plants and dysfunction of single components of innate immunity may provoke severe disease. Here we describe how mutations in the cystic fibrosis transmembrane conductance regulator gene dysregulate a variety of components of the innate immune system in individuals suffering from the hereditary disease cystic fibrosis. In the airways of these individuals, functions of the mucociliary clearance system, cationic antimicrobial (poly)peptides and neutrophils and macrophages are impaired and inflammatory signal transduction pathways exaggerated. Consequently, chronic airway colonization with opportunistic bacterial pathogens develops and leads to life-threatening lung disease.

[Imatinib--a possible therapeutic option for cervical carcinoma: results of a preclinical phase I study]

BACKGROUND

In the last few years, the therapy of cervical carcinoma has progressed substantially due to the use of simultaneous platinum- containing radiochemotherapy. However, there are no data which evaluate an individualized treatment adapted to tumor biology, in spite of the fact that patients show remarkably different responses to chemotherapy. Therefore this preclinical phase I study aims at finding therapeutic alternatives to the current cytostatic drugs to treat cervical carcinoma.

MATERIAL AND METHODS

In a tumor chemosensitivity assay, 8 drugs were tested on freshly isolated tumor cells of 16 patients [carbo- and cisplatin, topotecan, paclitaxel as well as the 2 tyrosine kinase inhibitors imatinib (Glivec) and gefitinib (Iressa (R) ) and the 2 monoclonal antibodies cetuximab (Erbitux) and trastuzumab (Herceptin (R) )].

RESULTS

Overall the test was evaluable for 16 specimens (100%). Ten of 15 tumor samples (66.6%) were sensitive to imatinib. A sensitive therapeutic response could be demonstrated in all tested FIGO stages. An interindividual comparison could establish sensitivity to cetuximab in 12.5% of cases, to gefitinib in 6.25%, to trastuzumab in 6.6%, to cisplatin in 13.3%, to carboplatin in 7.6%, to paclitaxel in 93.8% and to topotecan in 25%.

CONCLUSION

Imatinib seems to be an efficacious therapeutic option for patients with cervical carcinoma, independently of tumor subtype.

Targeted extended cystic fibrosis mutation testing on known and at-risk patients and relatives

This paper reports mathematically derived residual risks of being a carrier or being affected with cystic fibrosis following various screening scenarios to assist in interpreting test results and advising patients. While parental screening with 23 American College of Medical Genetics (ACMG) cystic fibrosis mutations defines the 64% of affected U.S. Caucasian fetuses with two detectable mutations, newborn screening for elevated immunoreactive trypsinogen (IRT) and sweat chloride identifies an additional 36% of affected newborns with zero or one detected mutation. The relatives of these affected newborns with less than two detectable mutations have higher posterior (after) 23 mutation-negative test risks of carrying undetected mutations. These calculations emphasize how knowledge of the mutations in the related affected patient substantially improves upon the quality of after-test advice to patients. Furthermore, negative tests of the partner without a family history and/or more extensive cystic fibrosis transmembrane conductance regulator (CFTR) gene testing also increases the likelihood that a negative report is truly negative. When a newborn patient with zero or one detected CFTR mutation has an inconclusive sweat test result, the sweat test should be repeated before ordering additional often unnecessary CFTR gene sequencing. Given the same composite mutation panel test accuracy, a higher proportion of reported test results would be correct during parental screening than when testing at-risk fetuses or symptomatic newborns. Prenatal and newborn screening would be enhanced substantially by medical professionals offering copies of all positive parental and newborn test reports to the parents to share with their relatives. These principles are likely to be applicable to other genetic diseases as the most common mutation frequencies are reported.

Resistance of Porphyromonas gingivalis ATCC 33277 to direct killing by antimicrobial peptides is protease independent

Antimicrobial peptides are short, positively charged, amphipathic peptides that possess a wide spectrum of antimicrobial activity and have an important role in the host's innate immunity. Lack of, or dysfunctions in, antimicrobial peptides have been correlated with infectious diseases, including periodontitis. Porphyromonas gingivalis, a gram-negative anaerobe and a major pathogen associated with periodontal diseases, is resistant to antimicrobial peptides of human and nonhuman origin, a feature that likely contributes to its virulence. Expressing a robust proteolytic activity, P. gingivalis hydrolyzes antimicrobial peptides. In this study, P. gingivalis inactivated three antimicrobial peptides, while a d-enantiomer was resistant to degradation. P. gingivalis was resistant to the protease-resistant d-enantiomer peptide, and importantly, a protease-deficient P. gingivalis mutant was also resistant to the antimicrobial peptide. Finally, the binding of a fluorescently labeled antimicrobial peptide to protease-deficient P. gingivalis was much weaker than the binding of susceptible Escherichia coli. Our results suggest that the resistance of P. gingivalis ATCC 33277 to direct killing by antimicrobial peptides is protease independent and results (at least partially) from the low affinity of antimicrobial peptides to P. gingivalis.