Reactive oxygen species involved in apoptosis induction of human respiratory epithelial (A549) cells by Streptococcus agalactiae

Costa, Andréia Ferreira Eduardo da; Moraes, João Alfredo; Oliveira, Jessica Silva Santos de; Santos, Michelle Hanthequeste Bittencourt dos; Santos, Gabriela da Silva; Barja‐Fidalgo, Christina; Mattos‐Guaraldi, Ana Luíza; Nagao, Prescilla Emy

doi:10.1099/mic.0.000202

Cited by 13 publications

(6 citation statements)

References 16 publications

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“…However, we did not detect significant caspase-1 activation in infected urothelial cells implicating non-pyroptotic cell death. While S. agalactiae can induce apoptosis in macrophages 42 48 49 this pathogen is also cytotoxic towards respiratory epithelial cells and elicits reactive oxygen species and apoptosis that encompasses caspase-3 and -9 50 . The low-level but statistically significant activation of caspase-3 in urothelial cells in response to infection with UPSA 807 is of interest because apoptosis in urothelial cells occurs following infection with uropathogenic E. coli ; the bacterial α-hemolysin activates caspase-3 in this cell death mechanism 26 51 .…”

Section: Discussionmentioning

confidence: 99%

Pathogenesis of Streptococcus urinary tract infection depends on bacterial strain and β-hemolysin/cytolysin that mediates cytotoxicity, cytokine synthesis, inflammation and virulence

Leclercq

Sullivan

Ipe

et al. 2016

Sci Rep

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Streptococcus agalactiae can cause urinary tract infection (UTI) including cystitis and asymptomatic bacteriuria (ABU). The early host-pathogen interactions that occur during S. agalactiae UTI and subsequent mechanisms of disease pathogenesis are poorly defined. Here, we define the early interactions between human bladder urothelial cells, monocyte-derived macrophages, and mouse bladder using uropathogenic S. agalactiae (UPSA) 807 and ABU-causing S. agalactiae (ABSA) 834 strains. UPSA 807 adhered, invaded and killed bladder urothelial cells more efficiently compared to ABSA 834 via mechanisms including low-level caspase-3 activation, and cytolysis, according to lactate dehydrogenase release measures and cell viability. Severe UPSA 807-induced cytotoxicity was mediated entirely by the bacterial β-hemolysin/cytolysin (β-H/C) because an β-H/C-deficient UPSA 807 isogenic mutant, UPSA 807ΔcylE, was not cytotoxic in vitro; the mutant was also significantly attenuated for colonization in the bladder in vivo. Analysis of infection-induced cytokines, including IL-8, IL-1β, IL-6 and TNF-α in vitro and in vivo revealed that cytokine and chemokine responses were dependent on expression of β-H/C that also elicited severe bladder neutrophilia. Thus, virulence of UPSA 807 encompasses adhesion to, invasion of and killing of bladder cells, pro-inflammatory cytokine/chemokine responses that elicit neutrophil infiltration, and β-H/C-mediated subversion of innate immune-mediated bacterial clearance from the bladder.

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Section: Discussionmentioning

confidence: 99%

Pathogenesis of Streptococcus urinary tract infection depends on bacterial strain and β-hemolysin/cytolysin that mediates cytotoxicity, cytokine synthesis, inflammation and virulence

Leclercq

Sullivan

Ipe

et al. 2016

Sci Rep

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“…Immunoblot analysis - HUVEC monolayers were infected with S. agalactiae for different time periods as described above. Following infection, the plates were chilled, and all subsequent steps were carried out at 4ºC as previously described ( Costa et al 2016 ). The HUVECs were then rinsed with PBS containing 0.4 mM Na 3 VO 4 and 1 mMNaF per mL.…”

Section: Methodsmentioning

confidence: 99%

Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells

Oliveira

Santos

Moraes

et al. 2018

Mem. Inst. Oswaldo Cruz

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BACKGROUND Streptococcus agalactiae can causes sepsis, pneumonia, and meningitis in neonates, the elderly, and immunocompromised patients. Although the virulence properties of S. agalactiae have been partially elucidated, the molecular mechanisms related to reactive oxygen species (ROS) generation in infected human endothelial cells need further investigation.OBJECTIVES This study aimed to evaluate the influence of oxidative stress in human umbilical vein endothelial cells (HUVECs) during S. agalactiae infection.METHODS ROS production during S. agalactiae-HUVEC infection was detected using the probe CM-H2DCFDA. Microfilaments labelled with phalloidin-FITC and p47phox-Alexa 546 conjugated were analysed by immunofluorescence. mRNA levels of p47phox (NADPH oxidase subunit) were assessed using Real Time qRT-PCR. The adherence and intracellular viability of S. agalactiae in HUVECs with or without pre-treatment of DPI, apocynin (NADPH oxidase inhibitors), and LY294002 (PI3K inhibitor) were evaluated by penicillin/gentamicin exclusion. Phosphorylation of p47phox and Akt activation by S. agalactiae were evaluated by immunoblotting analysis.FINDINGS Data showed increased ROS production 15 min after HUVEC infection. Real-Time qRT-PCR and western blotting performed in HUVEC infected with S. agalactiae detected alterations in mRNA levels and activation of p47phox. Pre-treatment of endothelial cells with NADPH oxidase (DPI and apocynin) and PI3K/Akt pathway (LY294002) inhibitors reduced ROS production, bacterial intracellular viability, and generation of actin stress fibres in HUVECs infected with S. agalactiae.CONCLUSIONS ROS generation via the NADPH oxidase pathway contributes to invasion of S. agalactiae in human endothelial cells accompanied by cytoskeletal reorganisation through the PI3K/Akt pathway, which provides novel evidence for the involvement of oxidative stress in S. agalactiae pathogenesis.

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“…Inhibition of its generation seems to be an important therapeutic target. This can be achieved by the use of apocynin, a molecule that inhibits the activation of NADPH oxidase by blocking one of its subunits [1–5].…”

Section: Introductionmentioning

confidence: 99%

Inhibition of NADPH Oxidase-Derived Reactive Oxygen Species Decreases Expression of Inflammatory Cytokines in A549 Cells

et al. 2019

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Various experimental models strongly support the hypothesis that airway inflammation can be caused by oxidative stress. Inflammatory airway diseases like asthma and COPD are characterized by higher levels of ROS and inflammatory cytokines. One of the sources of ROS is NADPH oxidase. Therefore, the aim of the study was to investigate influence of NADPH oxidase inhibition on the expression of IL-6, IL-8, TNF, TSLP, CD59, and PPAR-γ in vitro. A549 cells were incubated with apocynin in three concentrations (0.5 mg/ml, 1 mg/ml, and 3 mg/ml). Cells were trypsinized and RNA isolated after 1 h, 2 h, and 4 h of apocynin incubation at each concentration. Afterwards, reverse transcription was performed to evaluate mRNA expression using real-time PCR. The time-response and dose-response study showed that apocynin significantly influenced the relative expression of chosen genes (IL-6, IL-8, TNF, PPAR-γ, TSLP, and CD59). Apocynin decreased the mRNA expression of TNF-α at all concentrations used, and of IL-6 at concentrations of 1 and 3 mg/ml (p < 0.05). TSLP mRNA expression was also reduced by apocynin after 1 h and 2 h, and CD59 mRNA after 1 h, but only at the highest concentration. The expression of PPAR-γ was reduced after apocynin in the highest concentrations only (p < 0.05). The results might suggest that proinflammatory agents’ expression levels are strongly connected to the presence of oxidative stress generated by NADPH oxidase and this might be at least partially eliminated by anti-oxidative action. Apocynin, as an effective inhibitor of NADPH oxidase, seems to be useful in potential anti-oxidative and anti-inflammatory therapy.

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Reactive oxygen species involved in apoptosis induction of human respiratory epithelial (A549) cells by Streptococcus agalactiae

Cited by 13 publications

References 16 publications

Pathogenesis of Streptococcus urinary tract infection depends on bacterial strain and β-hemolysin/cytolysin that mediates cytotoxicity, cytokine synthesis, inflammation and virulence

Pathogenesis of Streptococcus urinary tract infection depends on bacterial strain and β-hemolysin/cytolysin that mediates cytotoxicity, cytokine synthesis, inflammation and virulence

Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells

Inhibition of NADPH Oxidase-Derived Reactive Oxygen Species Decreases Expression of Inflammatory Cytokines in A549 Cells

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