scholarly journals Protein A Modulates Neutrophil and Keratinocyte Signaling and Survival in Response to Staphylococcus aureus

2021 ◽  
Vol 11 ◽  
Author(s):  
Camila Ledo ◽  
Cintia D. Gonzalez ◽  
Ailin Garofalo ◽  
Florencia Sabbione ◽  
Irene A. Keitelman ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Death ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Protein A ◽  
Human Neutrophils ◽  
Potent Inducer ◽  
Tnf Α

The type 1 TNF-α receptor (TNFR1) has a central role in initiating both pro-inflammatory and pro-apoptotic signaling cascades in neutrophils. Considering that TNFR1 signals Staphylococcus aureus protein A (SpA), the aim of this study was to explore the interaction of this bacterial surface protein with neutrophils and keratinocytes to underscore the signaling pathways that may determine the fate of these innate immune cells in the infected tissue during staphylococcal skin infections. Using human neutrophils cultured in vitro and isogenic staphylococcal strains expressing or not protein A, we demonstrated that SpA is a potent inducer of IL-8 in neutrophils and that the induction of this chemokine is dependent on the SpA-TNFR1 interaction and p38 activation. In addition to IL-8, protein A induced the expression of TNF-α and MIP-1α highlighting the importance of SpA in the amplification of the inflammatory response. Protein A contributed to reduce neutrophil mortality prolonging their lifespan upon the encounter with S. aureus. Signaling initiated by SpA modulated the type of neutrophil cell death in vitro and during skin and soft tissue infections (SSTI) in vivo triggering the apoptotic pathway instead of necrosis. Moreover, SpA induced pro-inflammatory cytokines in keratinocytes, modulating their survival in vitro and preventing the exacerbated necrosis and ulceration of the epithelium during SSTI in vivo. Taken together, these results highlight the importance of the inflammatory signaling induced by protein A in neutrophils and skin epithelial cells. The ability of protein A to modulate the neutrophil/epithelial cell death program in the skin is of clinical relevance considering that lysis of neutrophils and epithelial cells will promote an intense inflammatory response and contribute to tissue damage, a non-desirable feature of complicated SSTI.

scholarly journals Cell Wall-associated Protein A as a Tool for Immunolocalization of Staphylococcus aureus in Infected Human Airway Epithelium

2000 ◽  
Vol 48 (4) ◽  
pp. 523-533 ◽  
Author(s):  
Emmanuel Mongodin ◽  
Odile Bajolet ◽  
Jocelyne Hinnrasky ◽  
Edith Puchelle ◽  
Sophie de Bentzmann
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Epithelial Cells ◽  
Airway Epithelium ◽  
Protein A ◽  
Staphylococcal Protein A ◽  
Basal Cells ◽  
Bronchial Diseases

Staphylococcus aureus is a common human pathogen involved in non-bronchial diseases and in genetic and acquired bronchial diseases. In this study, we applied an immunolabeling approach for in vivo and in vitro detection of S. aureus, based on the affinity of staphylococcal protein A (SpA) for the Fc region of immunoglobulins, especially IgG. Most strains of S. aureus, including clinical strains, can be detected with this labeling technique. The approach can be used for detection and localization with transmission electron microscopy or light-fluorescence microscopy of S. aureus in infected tissues such as human bronchial tissue from cystic fibrosis (CF) patients. The methodology can also be applied to cell culture models with the aim of characterizing bacterial adherence to epithelial cells in backscattered electron imaging with scanning electron microscopy. Application to the study of S. aureus adherence to airway epithelium showed that the bacteria did not adhere in vivo to intact airway epithelium. In contrast, bacteria adhered to the basolateral plasma membrane of columnar cells, to basal cells, to the basement membrane and were identified beneath the lamina propria when the epithelium was injured and remodeled, or in vitro when the epithelial cells were dedifferentiated.

scholarly journals Bacterium-Dependent Induction of Cytokines in Mononuclear Cells and Their Pathologic Consequences In Vivo

1999 ◽  
Vol 67 (5) ◽  
pp. 2125-2130 ◽  
Author(s):  
Yanling Jiang ◽  
Luciano Magli ◽  
Michael Russo
Keyword(s):  
Inflammatory Response ◽  
Mononuclear Cells ◽  
Oral Bacteria ◽  
Interleukin 12 ◽  
Potent Inducer ◽  
Tnf Α ◽  
Oral Pathogens ◽  
Ifn Γ

ABSTRACT Viridans streptococci are a heterogeneous group of gram-positive bacteria that are normal inhabitants of the mouth. These organisms are thought to contribute significantly to the etiology of infective endocarditis, although recently they have been implicated in serious infections in other settings. Another group of oral bacteria, gram-negative anaerobes, is associated with chronic dental infections, such as periodontal diseases or endodontic lesion formation. We evaluated the ability of the oral pathogens Streptococcus mutans and Porphyromonas endodontalis to induce a pathogenic response in vivo, with the goal of quantifying the inflammatory response in soft tissue by measuring leukocyte recruitment and hard tissues by measuring osteoclastogenesis. S. mutansinduced a strong inflammatory response and was a potent inducer of osteoclast formation, while P. endodontalis was not. To further study the mechanisms by which P. endodontalis andS. mutans elicit significantly different levels of inflammatory responses in vivo, we tested the capacity of each to induce production of cytokines by mononuclear cells in vitro. S. mutans stimulated high levels of interleukin-12 (IL-12), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), all of which are associated with inflammation, enhanced monocyte function, and generation of a Th1 response. In contrast, P. endodontalisstimulated production of IL-10 but not of TNF-α, IL-12, or IFN-γ. These results demonstrate that oral pathogens differ dramatically in their abilities to induce inflammatory and immunoregulatory cytokines. Moreover, there is a high degree of correlation between the cytokine profile induced by these bacteria in vitro and their pathogenic capacity in vivo.

scholarly journals TNF-α Triggers RIP1/FADD/Caspase-8-Mediated Apoptosis of Astrocytes and RIP3/MLKL-Mediated Necroptosis of Neurons Induced by Angiostrongylus cantonensis Infection

2021 ◽  
Author(s):  
Hongli Zhou ◽  
Minyu Zhou ◽  
Yue Hu ◽  
Yanin Limpanon ◽  
Yubin Ma ◽  
...  
Keyword(s):  
Cell Death ◽  
Enrichment Analysis ◽  
Angiostrongylus Cantonensis ◽  
Gene Set Enrichment Analysis ◽  
Caspase 8 ◽  
Cns Injury ◽  
Vitro Assay ◽  
Tnf Α

AbstractAngiostrongylus cantonensis (AC) can cause severe eosinophilic meningitis or encephalitis in non-permissive hosts accompanied by apoptosis and necroptosis of brain cells. However, the explicit underlying molecular basis of apoptosis and necroptosis upon AC infection has not yet been elucidated. To determine the specific pathways of apoptosis and necroptosis upon AC infection, gene set enrichment analysis (GSEA) and protein–protein interaction (PPI) analysis for gene expression microarray (accession number: GSE159486) of mouse brain infected by AC revealed that TNF-α likely played a central role in the apoptosis and necroptosis in the context of AC infection, which was further confirmed via an in vivo rescue assay after treating with TNF-α inhibitor. The signalling axes involved in apoptosis and necroptosis were investigated via immunoprecipitation and immunoblotting. Immunofluorescence was used to identify the specific cells that underwent apoptosis or necroptosis. The results showed that TNF-α induced apoptosis of astrocytes through the RIP1/FADD/Caspase-8 axis and induced necroptosis of neurons by the RIP3/MLKL signalling pathway. In addition, in vitro assay revealed that TNF-α secretion by microglia increased upon LSA stimulation and caused necroptosis of neurons. The present study provided the first evidence that TNF-α was secreted by microglia stimulated by AC infection, which caused cell death via parallel pathways of astrocyte apoptosis (mediated by the RIP1/FADD/caspase-8 axis) and neuron necroptosis (driven by the RIP3/MLKL complex). Our research comprehensively elucidated the mechanism of cell death after AC infection and provided new insight into targeting TNF-α signalling as a therapeutic strategy for CNS injury.

scholarly journals Expression of lipocortins in human bronchial epithelial cells: effects of IL-1β , TNF-α, LPS and dexamethasone

1996 ◽  
Vol 5 (3) ◽  
pp. 210-217
Author(s):  
M. M. Verheggen ◽  
H. I. M. de Bont ◽  
P. W. C. Adriaansen-Soeting ◽  
B. J. A. Goense ◽  
C. J. A. M. Tak ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Bronchial Epithelium ◽  
Northern Blotting ◽  
Bronchial Epithelial Cells ◽  
Human Bronchial Epithelial Cells ◽  
Bronchial Epithelial ◽  
Annexin I ◽  
Tnf Α

In this study, we investigated the expression of lipocortin I and II (annexin I and I in the human bronchial epithelium, bothin vivoandin vitro. A clear expression of lipocortin I and II protein was found in the epithelium in sections of bronchial tissue. In cultured human bronchial epithelial cells we demonstrated the expression of lipocortin I and II mRNA and protein using Northern blotting, FACScan analysis and ELISA. No induction of lipocortin I or II mRNA or protein was observed after incubation with dexamethasone. Stimulation of bronchial epithelial cells with IL-1β, TNF-α or LPS for 24 h did not affect the lipocortin I or II mRNA or protein expression, although PGE2and 6-keto-PGF1αproduction was significantly increased. This IL-1β- and LPS-mediated increase in eicosanoids could be reduced by dexamethasone, but was not accompanied by an increase in lipocortin I or II expression. In human bronchial epithelial cells this particular glucocorticoid action is not mediated through lipocortin I or II induction.

scholarly journals The Synergistic Effect of Nicotine and Staphylococcus aureus on Peri-Implant Infections

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Hu ◽  
Wen Zhou ◽  
Chengguang Zhu ◽  
Yujie Zhou ◽  
Qiang Guo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Synergistic Effects ◽  
Protein A ◽  
Treated Group ◽  
Combination Group ◽  
Staphylococcal Protein A ◽  
Receptor Activator ◽  
And Staphylococcus Aureus

Smoking is considered a key risk factor for implant survival; however, how it interacts with the pathogens in peri-implant infections is not clear. Here, we identified that nicotine, the key component of cigarette smoking, can interact with Staphylococcus aureus and synergistically induce peri-implant infections in a rat osteolysis model. The nicotine–S. aureus combination group increased the gross bone pathology, osteolysis, periosteal reactions, and bone resorption compared to the nicotine or S. aureus single treated group (p < 0.05). Nicotine did not promote the proliferation of S. aureus both in vitro and in vivo, but it can significantly upregulate the expression of staphylococcal protein A (SpA), a key virulence factor of S. aureus. The nicotine–S. aureus combination also synergistically activated the expression of RANKL (receptor activator of nuclear factor-kappa B ligand, p < 0.05) to promote the development of peri-implant infections. The synergistic effects between nicotine and S. aureus infection can be a new target to reduce the peri-implant infections.

scholarly journals MiR-22-3p suppresses sepsis-induced acute kidney injury by targeting PTEN

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Xudong Wang ◽  
Yali Wang ◽  
Mingjian Kong ◽  
Jianping Yang
Keyword(s):  
Acute Kidney Injury ◽  
Inflammatory Response ◽  
Periodic Acid ◽  
Kidney Injury ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
Tnf Α

Abstract Background: Septic acute kidney injury is considered as a severe and frequent complication that occurs during sepsis. The present study was performed to understand the role of miR-22-3p and its underlying mechanism in sepsis-induced acute kidney injury. Methods: Rats were injected with adenovirus carrying miR-22-3p or miR-NC in the caudal vein before cecal ligation. Meanwhile, HK-2 cells were transfected with the above adenovirus following LPS stimulation. We measured the markers of renal injury (blood urea nitrogen (BUN), serum creatinine (SCR)). Histological changes in kidney tissues were examined by hematoxylin and eosin (H&E), Masson staining, periodic acid Schiff staining and TUNEL staining. The levels of IL-1β, IL-6, TNF-α and NO were determined by ELISA assay. Using TargetScan prediction and luciferase reporter assay, we predicted and validated the association between PTEN and miR-22-3p. Results: Our data showed that miR-22-3p was significantly down-regulated in a rat model of sepsis-induced acute kidney injury, in vivo and LPS-induced sepsis model in HK-2 cells, in vitro. Overexpression of miR-22-3p remarkably suppressed the inflammatory response and apoptosis via down-regulating HMGB1, p-p65, TLR4 and pro-inflammatory factors (IL-1β, IL-6, TNF-α and NO), both in vivo and in vitro. Moreover, PTEN was identified as a target of miR-22-3p. Furthermore, PTEN knockdown augmented, while overexpression reversed the suppressive role of miR-22-3p in LPS-induced inflammatory response. Conclusions: Our results showed that miR-22-3p induced protective role in sepsis-induced acute kidney injury may rely on the repression of PTEN.

scholarly journals A Comparative Transcriptome Analysis of Human and Porcine Choroid Plexus Cells in Response to Streptococcus suis Serotype 2 Infection Points to a Role of Hypoxia

2021 ◽  
Vol 11 ◽  
Author(s):  
Alexa N. Lauer ◽  
Rene Scholtysik ◽  
Andreas Beineke ◽  
Christoph Georg Baums ◽  
Kristin Klose ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Response ◽  
Choroid Plexus ◽  
Cellular Proliferation ◽  
Inflammatory Responses ◽  
Streptococcus Suis ◽  
Gene Set Enrichment Analysis ◽  
Rna Seq

Streptococcus suis (S. suis) is an important opportunistic pathogen, which can cause septicemia and meningitis in pigs and humans. Previous in vivo observations in S. suis-infected pigs revealed lesions at the choroid plexus (CP). In vitro experiments with primary porcine CP epithelial cells (PCPEC) and human CP epithelial papilloma (HIBCPP) cells demonstrated that S. suis can invade and traverse the CP epithelium, and that the CP contributes to the inflammatory response via cytokine expression. Here, next generation sequencing (RNA-seq) was used to compare global transcriptome profiles of PCPEC and HIBCPP cells challenged with S. suis serotype (ST) 2 infected in vitro, and of pigs infected in vivo. Identified differentially expressed genes (DEGs) were, amongst others, involved in inflammatory responses and hypoxia. The RNA-seq data were validated via quantitative PCR of selected DEGs. Employing Gene Set Enrichment Analysis (GSEA), 18, 28, and 21 enriched hallmark gene sets (GSs) were identified for infected HIBCPP cells, PCPEC, and in the CP of pigs suffering from S. suis ST2 meningitis, respectively, of which eight GSs overlapped between the three different sample sets. The majority of these GSs are involved in cellular signaling and pathways, immune response, and development, including inflammatory response and hypoxia. In contrast, suppressed GSs observed during in vitro and in vivo S. suis ST2 infections included those, which were involved in cellular proliferation and metabolic processes. This study suggests that similar cellular processes occur in infected human and porcine CP epithelial cells, especially in terms of inflammatory response.

scholarly journals Three-Dimensional In Vitro Staphylococcus aureus Abscess Communities Display Antibiotic Tolerance and Protection from Neutrophil Clearance

2020 ◽  
Vol 88 (11) ◽  
Author(s):  
Marloes I. Hofstee ◽  
Martijn Riool ◽  
Igors Terjajevs ◽  
Keith Thompson ◽  
Martin J. Stoddart ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Cells ◽  
Early Stage ◽  
Three Dimensional ◽  
Collagen Gel ◽  
Maximum Size ◽  
Human Neutrophils ◽  
Content Type

ABSTRACT Staphylococcus aureus is a prominent human pathogen in bone and soft-tissue infections. Pathophysiology involves abscess formation, which consists of central staphylococcal abscess communities (SACs), surrounded by a fibrin pseudocapsule and infiltrating immune cells. Protection against the ingress of immune cells such as neutrophils, or tolerance to antibiotics, remains largely unknown for SACs and is limited by the lack of availability of in vitro models. We describe a three-dimensional in vitro model of SACs grown in a human plasma-supplemented collagen gel. The in vitro SACs reached their maximum size by 24 h and elaborated a fibrin pseudocapsule, as confirmed by electron and immunofluorescence microscopy. The in vitro SACs tolerated 100× the MIC of gentamicin alone and in combination with rifampin, while planktonic controls and mechanically dispersed SACs were efficiently killed. To simulate a host response, SACs were exposed to differentiated PLB-985 neutrophil-like (dPLB) cells and to primary human neutrophils at an early stage of SAC formation or after maturation at 24 h. Both cell types were unable to clear mature in vitro SACs, but dPLB cells prevented SAC growth upon early exposure before pseudocapsule maturation. Neutrophil exposure after plasmin pretreatment of the SACs resulted in a significant decrease in the number of bacteria within the SACs. The in vitro SAC model mimics key in vivo features, offers a new tool to study host-pathogen interactions and drug efficacy assessment, and has revealed the functionality of the S. aureus pseudocapsule in protecting the bacteria from host phagocytic responses and antibiotics.

scholarly journals Bcl-2 overexpression in type II epithelial cells does not prevent hyperoxia-induced acute lung injury in mice

2010 ◽  
Vol 299 (3) ◽  
pp. L312-L322 ◽  
Author(s):  
Isabelle Métrailler-Ruchonnet ◽  
Alessandra Pagano ◽  
Stéphanie Carnesecchi ◽  
Karim Khatib ◽  
Pedro Herrera ◽  
...  
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Ex Vivo ◽  
Lung Damage ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lung Weight

Bcl-2 is an anti-apoptotic molecule preventing oxidative stress damage and cell death. We have previously shown that Bcl-2 is able to prevent hyperoxia-induced cell death when overexpressed in a murine fibrosarcoma cell line L929. We hypothesized that its specific overexpression in pulmonary epithelial type II cells could prevent hyperoxia-induced lung injury by protecting the epithelial side of the alveolo-capillary barrier. In the present work, we first showed that in vitro Bcl-2 can rescue murine pulmonary epithelial cells (MLE12) from oxygen-induced cell apoptosis, as shown by analysis of LDH release, annexin V/propidium staining, and caspase-3 activity. We then generated transgenic mice overexpressing specifically Bcl-2 in lung epithelial type II cells under surfactant protein C (SP-C) promoter (Tg-Bcl-2) and exposed them to hyperoxia. Bcl-2 did not hinder hyperoxia-induced mitochondria and DNA oxidative damage of type II cell in vivo. Accordingly, lung damage was identical in both Tg-Bcl-2 and littermate mice strains, as measured by lung weight, bronchoalveolar lavage, and protein content. Nevertheless, we observed a significant lower number of TUNEL-positive cells in type II cells isolated from Tg-Bcl-2 mice exposed to hyperoxia compared with cells isolated from littermate mice. In summary, these results show that although Bcl-2 overexpression is able to prevent hyperoxia-induced cell death at single cell level in vitro and ex vivo, it is not sufficient to prevent cell death of parenchymal cells and to protect the lung from acute damage in mice.

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