Group B Streptococcus induces tyrosine phosphorylation of annexin V and glutathione S-transferase in human umbilical vein endothelial cells

Santos, Gabriela Silva; Penha, Carla-Veronica Loureiro y; Mattos‐Guaraldi, Ana Luíza; Attias, Márcia; Lópes-Bezerra, Leila M.; Silva-Filho, F. C.; Nagao, Prescilla Emy

doi:10.3892/ijmm_00000245

Cited by 4 publications

(1 citation statement)

References 33 publications

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“…These findings demonstrate that GBS isolates are able to adhere and invade astrocytes to varying degrees, which may be due to differences in cell surface expressed determinants resulting in divergent affinities or capacities for binding to human astrocytes. The variable invasiveness exhibited by the different GBS strains has been previously observed for other cell types such as human vaginal epithelial cells [ 40 ], human pulmonary alveolar epithelial cells (A549)[ 41 ], human umbilical vein endothelial cells (HUVEC)[ 42 ], and human brain endothelial cells (hBMEC) [ 3 , 43 ]. Interestingly, there was no correlation between the ability of GBS to adhere versus invade astrocytic cells ( Fig 3A and 3B ).…”

Section: Resultsmentioning

confidence: 98%

Group B Streptococcal Infection and Activation of Human Astrocytes

et al. 2015

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Background Streptococcus agalactiae (Group B Streptococcus, GBS) is the leading cause of life-threatening meningitis in human newborns in industrialized countries. Meningitis results from neonatal infection that occurs when GBS leaves the bloodstream (bacteremia), crosses the blood-brain barrier (BBB), and enters the central nervous system (CNS), where the bacteria contact the meninges. Although GBS is known to invade the BBB, subsequent interaction with astrocytes that physically associate with brain endothelium has not been well studied.Methodology/Principal FindingsWe hypothesize that human astrocytes play a unique role in GBS infection and contribute to the development of meningitis. To address this, we used a well- characterized human fetal astrocyte cell line, SVG-A, and examined GBS infection in vitro. We observed that all GBS strains of representative clinically dominant serotypes (Ia, Ib, III, and V) were able to adhere to and invade astrocytes. Cellular invasion was dependent on host actin cytoskeleton rearrangements, and was specific to GBS as Streptococcus gordonii failed to enter astrocytes. Analysis of isogenic mutant GBS strains deficient in various cell surface organelles showed that anchored LTA, serine-rich repeat protein (Srr1) and fibronectin binding (SfbA) proteins all contribute to host cell internalization. Wild-type GBS also displayed an ability to persist and survive within an intracellular compartment for at least 12 h following invasion. Moreover, GBS infection resulted in increased astrocyte transcription of interleukin (IL)-1β, IL-6 and VEGF.Conclusions/SignificanceThis study has further characterized the interaction of GBS with human astrocytes, and has identified the importance of specific virulence factors in these interactions. Understanding the role of astrocytes during GBS infection will provide important information regarding BBB disruption and the development of neonatal meningitis.

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Section: Resultsmentioning

confidence: 98%

Group B Streptococcal Infection and Activation of Human Astrocytes

et al. 2015

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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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Involvement of lipid microdomains in human endothelial cells infected by Streptococcus agalactiae type III belonging to the hypervirulent ST-17

Ferreira

Lannes-Costa

Santos

et al. 2020

Mem. Inst. Oswaldo Cruz

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BACKGROUND Streptococcus agalactiae capsular type III strains are a leading cause of invasive neonatal infections. Many pathogens have developed mechanisms to escape from host defense response using the host membrane microdomain machinery. Lipid rafts play an important role in a variety of cellular functions and the benefit provided by interaction with lipid rafts can vary from one pathogen to another. OBJECTIVES This study aims to evaluate the involvement of membrane microdomains during infection of human endothelial cell by S. agalactiae. METHODS The effects of cholesterol depletion and PI3K/AKT signaling pathway activation during S. agalactiae-human umbilical vein endothelial cells (HUVEC) interaction were analysed by pre-treatment with methyl-β-cyclodextrin (MβCD) or LY294002 inhibitors, immunofluorescence and immunoblot analysis. The involvement of lipid rafts was analysed by colocalisation of bacteria with flotillin-1 and caveolin-1 using fluorescence confocal microscopy. FINDINGSIn this work, we demonstrated the importance of the integrity of lipid rafts microdomains and activation of PI3K/Akt pathway during invasion of S. agalactiae strain to HUVEC cells. Our results suggest the involvement of flotillin-1 and caveolin-1 during the invasion of S. agalactiae strain in HUVEC cells.CONCLUSIONS The collection of our results suggests that lipid microdomain affects the interaction of S. agalactiae type III belonging to the hypervirulent ST-17 with HUVEC cells through PI3K/Akt signaling pathway.Key words: S. agalactiae -lipid rafts -flotillin-1 -caveolin-1 -HUVEC -PI3K/Akt pathway Streptococcus agalactiae is a leading cause of neonatal infections, such as meningitis, sepsis and pneumonia. (1) In particular, S. agalactiae capsular type III strains belonging to the hypervirulent clonal complex 17 have been significantly associated with meningitis and account for up to 44 early onset disease and 67% late onset disease cases compared with less than 10% of colonising isolates. (2,3) Microorganisms interact with host cell lipid rafts microdomains to enter and survive inside the cell. (4) Lipid rafts play an important role in a variety of cellular functions, including polarisation, signal transduction, endocytosis, secretion, cell-cell and cell-pathogen adhesion. Several pathogens, such as viruses, bacteria and protozoa, can use the host-cell lipid rafts to secure their entrance and maintenance inside target cells. The benefit provided by interaction with lipid rafts can vary from one pathogen to another. (5) Lipid rafts are considered as dynamic assemblies of cholesterol and sphingolipids in

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Group B Streptococcus induces tyrosine phosphorylation of annexin V and glutathione S-transferase in human umbilical vein endothelial cells

Cited by 4 publications

References 33 publications

Group B Streptococcal Infection and Activation of Human Astrocytes

Group B Streptococcal Infection and Activation of Human Astrocytes

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

Involvement of lipid microdomains in human endothelial cells infected by Streptococcus agalactiae type III belonging to the hypervirulent ST-17

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