1
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De-Leon-Lopez YS, Thompson ME, Kean JJ, Flaherty RA. The PI3K-Akt pathway is a multifaceted regulator of the macrophage response to diverse group B Streptococcus isolates. Front Cell Infect Microbiol 2023; 13:1258275. [PMID: 37928185 PMCID: PMC10622663 DOI: 10.3389/fcimb.2023.1258275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/25/2023] [Indexed: 11/07/2023] Open
Abstract
Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a common member of the microbial flora in healthy individuals. However, problems may arise when GBS-colonized mothers become pregnant. GBS may be transferred from a colonized mother to her newborn or developing fetus, which may result in complications such as miscarriage, pre-term birth, meningitis, pneumonia, or sepsis. Macrophages play an especially important role in the fetal and newborn response to GBS due to the limited development of the adaptive immune system early in life. The goal of this study was to expand what is currently known about how GBS manipulates macrophage cell signaling to evade the immune system and cause disease. To this end, we investigated whether the PI3K-Akt pathway was involved in several key aspects of the macrophage response to GBS. We explored whether certain GBS strains, such as sequence type (ST)-17 strains, rely on this pathway for the more rapid macrophage uptake they induce compared to other GBS strains. Our findings suggest that this pathway is, indeed, important for macrophage uptake of GBS. Consistent with these findings, we used immunofluorescence microscopy to demonstrate that more virulent strains of GBS induce more actin projections in macrophages than less virulent strains. Additionally, we explored whether PI3K-Akt signaling impacted the ability of GBS to survive within macrophages after phagocytosis and whether this pathway influenced the survival rate of macrophages themselves following GBS infection. The PI3K-Akt pathway was found to promote the survival of both macrophages and intracellular GBS following infection. We also observed that inhibition of the PI3K-Akt pathway significantly reduced GBS-mediated activation of NFκB, which is a key regulator of cell survival and inflammatory responses. Overall, these insights into strain-dependent GBS-mediated manipulation of the PI3K-Akt pathway and its downstream targets in infected macrophages may provide new insights for the development of diagnostic and therapeutic tools to combat severe GBS disease.
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Affiliation(s)
| | | | | | - Rebecca A. Flaherty
- Department of Biology and Health Science, Aquinas College, Grand Rapids, MI, United States
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2
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Shabayek S, Abdellah AM, Salah M, Ramadan M, Fahmy N. Alterations of the vaginal microbiome in healthy pregnant women positive for group B Streptococcus colonization during the third trimester. BMC Microbiol 2022; 22:313. [PMID: 36544085 PMCID: PMC9769055 DOI: 10.1186/s12866-022-02730-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Streptococcus agalactiae or group B Streptococcus (GBS) asymptomatically colonizes the genitourinary tracts of up to 30% of pregnant women. Globally, GBS is an important cause of neonatal morbidity and mortality. GBS has recently been linked to adverse pregnancy outcomes. The potential interactions between GBS and the vaginal microbiome composition remain poorly understood. In addition, little is known about the vaginal microbiota of pregnant Egyptian women. RESULTS Using V3-V4 16S rRNA next-generation sequencing, we examined the vaginal microbiome in GBS culture-positive pregnant women (22) and GBS culture-negative pregnant women (22) during the third trimester in Ismailia, Egypt. According to the alpha-diversity indices, the vaginal microbiome of pregnant GBS culture-positive women was significantly more diverse and less homogenous. The composition of the vaginal microbiome differed significantly based on beta-diversity between GBS culture-positive and culture-negative women. The phylum Firmicutes and the family Lactobacillaceae were significantly more abundant in GBS-negative colonizers. In contrast, the phyla Actinobacteria, Tenericutes, and Proteobacteria and the families Bifidobacteriaceae, Mycoplasmataceae, Streptococcaceae, Corynebacteriaceae, Staphylococcaceae, and Peptostreptococcaceae were significantly more abundant in GBS culture-positive colonizers. On the genus and species levels, Lactobacillus was the only genus detected with significantly higher relative abundance in GBS culture-negative status (88%), and L. iners was the significantly most abundant species. Conversely, GBS-positive carriers exhibited a significant decrease in Lactobacillus abundance (56%). In GBS-positive colonizers, the relative abundance of the genera Ureaplasma, Gardnerella, Streptococcus, Corynebacterium, Staphylococcus, and Peptostreptococcus and the species Peptostreptococcus anaerobius was significantly higher. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to the metabolism of cofactors and vitamins, phosphatidylinositol signaling system, peroxisome, host immune system pathways, and host endocrine system were exclusively enriched among GBS culture-positive microbial communities. However, lipid metabolism KEGG pathways, nucleotide metabolism, xenobiotics biodegradation and metabolism, genetic information processing pathways associated with translation, replication, and repair, and human diseases (Staphylococcus aureus infection) were exclusively enriched in GBS culture-negative communities. CONCLUSIONS Understanding how perturbations of the vaginal microbiome contribute to pregnancy complications may result in the development of alternative, targeted prevention strategies to prevent maternal GBS colonization. We hypothesized associations between inferred microbial function and GBS status that would need to be confirmed in larger cohorts.
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Affiliation(s)
- Sarah Shabayek
- grid.33003.330000 0000 9889 5690Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Asmaa M. Abdellah
- grid.33003.330000 0000 9889 5690Department of Obstetrics and Gynecology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Mohammed Salah
- grid.440879.60000 0004 0578 4430Department of Microbiology and Immunology, Faculty of Pharmacy, Port Said University, Port Said, Egypt
| | - Mohammed Ramadan
- grid.411303.40000 0001 2155 6022Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
| | - Nora Fahmy
- grid.33003.330000 0000 9889 5690Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
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3
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Group B Streptococcus-Induced Macropinocytosis Contributes to Bacterial Invasion of Brain Endothelial Cells. Pathogens 2022; 11:pathogens11040474. [PMID: 35456149 PMCID: PMC9028350 DOI: 10.3390/pathogens11040474] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 01/25/2023] Open
Abstract
Bacterial meningitis is defined as serious inflammation of the central nervous system (CNS) in which bacteria infect the blood–brain barrier (BBB), a network of highly specialized brain endothelial cells (BECs). Dysfunction of the BBB is a hallmark of bacterial meningitis. Group B Streptococcus (GBS) is one of the leading organisms that cause bacterial meningitis, especially in neonates. Macropinocytosis is an actin-dependent form of endocytosis that is also tightly regulated at the BBB. Previous studies have shown that inhibition of actin-dependent processes decreases bacterial invasion, suggesting that pathogens can utilize macropinocytotic pathways for invasion. The purpose of this project is to study the factors that lead to dysfunction of the BBB. We demonstrate that infection with GBS increases rates of endocytosis in BECs. We identified a potential pathway, PLC-PKC-Nox2, in BECs that contributes to macropinocytosis regulation. Here we demonstrate that downstream inhibition of PLC, PKC, or Nox2 significantly blocks GBS invasion of BECs. Additionally, we show that pharmacological activation of PKC can turn on macropinocytosis and increase bacterial invasion of nonpathogenic yet genetically similar Lactococcus lactis. Our results suggest that GBS activates BEC signaling pathways that increase rates of macropinocytosis and subsequently the invasion of GBS.
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Ferreira BJ, Lannes-Costa PS, Santos GDS, Mermelstein C, Einicker-Lamas M, Nagao PE. Involvement of lipid microdomains in human endothelial cells infected by Streptococcus agalactiae type III belonging to the hypervirulent ST-17. Mem Inst Oswaldo Cruz 2020; 115:e190398. [PMID: 32187326 PMCID: PMC7066991 DOI: 10.1590/0074-02760190398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 02/05/2020] [Indexed: 11/24/2022] Open
Abstract
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. FINDINGS In 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.
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Affiliation(s)
- Beatriz Jandre Ferreira
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes, Laboratório de Biologia Molecular e Fisiologia de Estreptococos, Rio de Janeiro, RJ, Brasil
| | - Pamella Silva Lannes-Costa
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes, Laboratório de Biologia Molecular e Fisiologia de Estreptococos, Rio de Janeiro, RJ, Brasil
| | - Gabriela da Silva Santos
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes, Laboratório de Biologia Molecular e Fisiologia de Estreptococos, Rio de Janeiro, RJ, Brasil
| | - Cláudia Mermelstein
- Universidade Federal do Rio de Janeiro, Instituto de Ciências Biomédicas, Rio de Janeiro, RJ, Brasil
| | - Marcelo Einicker-Lamas
- Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
| | - Prescilla Emy Nagao
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcântara Gomes, Laboratório de Biologia Molecular e Fisiologia de Estreptococos, Rio de Janeiro, RJ, Brasil
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5
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Meningitic Escherichia coli Induction of ANGPTL4 in Brain Microvascular Endothelial Cells Contributes to Blood-Brain Barrier Disruption via ARHGAP5/RhoA/MYL5 Signaling Cascade. Pathogens 2019; 8:pathogens8040254. [PMID: 31766605 PMCID: PMC6963727 DOI: 10.3390/pathogens8040254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/18/2022] Open
Abstract
Bacterial meningitis is currently recognized as one of the most important life-threatening infections of the central nervous system (CNS) with high morbidity and mortality, despite the advancements in antimicrobial treatment. The disruption of blood–brain barrier (BBB) induced by meningitis bacteria is crucial for the development of bacterial meningitis. However, the complete mechanisms involving in the BBB disruption remain to be elucidated. Here, we found meningitic Escherichia coli induction of angiopoietin-like 4 (ANGPTL4) in brain microvascular endothelial cells (BMECs) contributes to BBB disruption via ARHGAP5/RhoA/MYL5 signaling cascade, by the demonstration that ANGPTL4 was significantly upregulated in meningitis E. coli infection of BMECs as well as mice, and treatment of the recombinant ANGPTL4 protein led to an increased permeability of the BBB in vitro and in vivo. Moreover, we found that ANGPTL4 did not affect the expression of tight junction proteins involved in BBB disruption, but it increased the expression of MYL5, which was found to have a negative role on the regulation of barrier function during meningitic E. coli infection, through the activation of RhoA signaling pathway. To our knowledge, this is the first report demonstrating the disruption of BBB induced by ANGPTL4 through the ARHGAP5/RhoA/MYL5 pathway, which largely supports the involvement of ANGPTL4 during meningitic E. coli invasion and further expands the theoretical basis for the mechanism of bacterial meningitis.
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6
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Guimarães AJ, de Cerqueira MD, Zamith-Miranda D, Lopez PH, Rodrigues ML, Pontes B, Viana NB, DeLeon-Rodriguez CM, Rossi DCP, Casadevall A, Gomes AMO, Martinez LR, Schnaar RL, Nosanchuk JD, Nimrichter L. Host membrane glycosphingolipids and lipid microdomains facilitate Histoplasma capsulatum internalisation by macrophages. Cell Microbiol 2018; 21:e12976. [PMID: 30427108 DOI: 10.1111/cmi.12976] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 09/03/2018] [Accepted: 09/17/2018] [Indexed: 12/17/2022]
Abstract
Recognition and internalisation of intracellular pathogens by host cells is a multifactorial process, involving both stable and transient interactions. The plasticity of the host cell plasma membrane is fundamental in this infectious process. Here, the participation of macrophage lipid microdomains during adhesion and internalisation of the fungal pathogen Histoplasma capsulatum (Hc) was investigated. An increase in membrane lateral organisation, which is a characteristic of lipid microdomains, was observed during the first steps of Hc-macrophage interaction. Cholesterol enrichment in macrophage membranes around Hc contact regions and reduced levels of Hc-macrophage association after cholesterol removal also suggested the participation of lipid microdomains during Hc-macrophage interaction. Using optical tweezers to study cell-to-cell interactions, we showed that cholesterol depletion increased the time required for Hc adhesion. Additionally, fungal internalisation was significantly reduced under these conditions. Moreover, macrophages treated with the ceramide-glucosyltransferase inhibitor (P4r) and macrophages with altered ganglioside synthesis (from B4galnt1-/- mice) showed a deficient ability to interact with Hc. Coincubation of oligo-GM1 and treatment with Cholera toxin Subunit B, which recognises the ganglioside GM1, also reduced Hc association. Although purified GM1 did not alter Hc binding, treatment with P4 significantly increased the time required for Hc binding to macrophages. The content of CD18 was displaced from lipid microdomains in B4galnt1-/- macrophages. In addition, macrophages with reduced CD18 expression (CD18low ) were associated with Hc at levels similar to wild-type cells. Finally, CD11b and CD18 colocalised with GM1 during Hc-macrophage interaction. Our results indicate that lipid rafts and particularly complex gangliosides that reside in lipid rafts stabilise Hc-macrophage adhesion and mediate efficient internalisation during histoplasmosis.
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Affiliation(s)
- Allan J Guimarães
- Department of Microbiology and Parasitology, Biomedical Institute, Fluminense Federal University, Rio de Janeiro, Brazil.,Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York
| | - Mariana Duarte de Cerqueira
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniel Zamith-Miranda
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pablo H Lopez
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Marcio L Rodrigues
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil
| | - Bruno Pontes
- LPO-COPEA, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathan B Viana
- LPO-COPEA, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,LPO-COPEA, Institute of Physics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos M DeLeon-Rodriguez
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Diego Conrado Pereira Rossi
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Andre M O Gomes
- Program of Structural Biology, Institute of Medical Biochemistry Leopoldo de Meis and National Institute of Science and Technology of Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis R Martinez
- Biological Sciences, The University of Texas at El Paso, El Paso, Texas
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joshua D Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York
| | - Leonardo Nimrichter
- Department of General Microbiology, Microbiology Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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7
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D'Ippolito S, Di Nicuolo F, Pontecorvi A, Gratta M, Scambia G, Di Simone N. Endometrial microbes and microbiome: Recent insights on the inflammatory and immune "players" of the human endometrium. Am J Reprod Immunol 2018; 80:e13065. [PMID: 30375712 DOI: 10.1111/aji.13065] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/22/2018] [Accepted: 09/24/2018] [Indexed: 12/29/2022] Open
Abstract
In recent years, extended scientific works shed light on the important role played by the endometrium in early pregnancy. This review examines our current knowledge about the delicate balance between microbial and cellular immune agents at endometrial level: All of them might affect endometrial receptivity. In contrast to the classical thinking of human endometrium as a sterile tissue, several recent studies have drawn attention to a resident population of microorganisms, which reaches only a 30% of concordance with those of the cervical-vaginal flora. At present, the understanding of the microbiome in relation to human reproduction is in its infancy and further studies are needed to clarify the activity of endometrial microbiome and the possible effects of a "reproductive tract dysbiosis" on fertility. Moreover, in the human endometrium, there is a complex system works preventing the risk of infection as well as enabling, when pregnancy occurs, the acceptance of the blastocyst. In this way, the endometrium plays a central role in the uterine immune surveillance. A better understanding of the different agents that may affect endometrial receptivity would improve the diagnosis and treatment of obstetric complications related to defective implantation and placentation.
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Affiliation(s)
- Silvia D'Ippolito
- Dipartimento di Scienze della Salute della Donna e del Bambino, Area Salute Donna, Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italia.,Istituto di Clinica Ostetrica e Ginecologica, Università Cattolica del Sacro Cuore, Rome, Italia
| | - Fiorella Di Nicuolo
- Dipartimento di Scienze della Salute della Donna e del Bambino, Area Salute Donna, Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italia.,Paolo VI International Scientific Institute, Università Cattolica del Sacro Cuore, Rome, Italia
| | - Alfredo Pontecorvi
- Paolo VI International Scientific Institute, Università Cattolica del Sacro Cuore, Rome, Italia.,Dipartimento di Scienze Gastroenterologiche, Endocrino-Metaboliche e Nefro-Urologiche, Area Endocrino-Metabolica e Dermo-Reumatologica, Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italia.,Istituto di Patologia Medica, Università Cattolica del Sacro Cuore, Rome, Italia
| | - Matteo Gratta
- Istituto di Clinica Ostetrica e Ginecologica, Università Cattolica del Sacro Cuore, Rome, Italia
| | - Giovanni Scambia
- Dipartimento di Scienze della Salute della Donna e del Bambino, Area Salute Donna, Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italia.,Istituto di Clinica Ostetrica e Ginecologica, Università Cattolica del Sacro Cuore, Rome, Italia
| | - Nicoletta Di Simone
- Dipartimento di Scienze della Salute della Donna e del Bambino, Area Salute Donna, Fondazione Policlinico Universitario A.Gemelli IRCCS, Rome, Italia.,Istituto di Clinica Ostetrica e Ginecologica, Università Cattolica del Sacro Cuore, Rome, Italia
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8
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Reply to Gilchrist et al.: Possible roles for VAC14 in multiple infectious diseases. Proc Natl Acad Sci U S A 2018; 115:E3604-E3605. [PMID: 29588421 DOI: 10.1073/pnas.1803533115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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9
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Vornhagen J, Adams Waldorf KM, Rajagopal L. Perinatal Group B Streptococcal Infections: Virulence Factors, Immunity, and Prevention Strategies. Trends Microbiol 2017. [PMID: 28633864 DOI: 10.1016/j.tim.2017.05.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Group B streptococcus (GBS) or Streptococcus agalactiae is a β-hemolytic, Gram-positive bacterium that is a leading cause of neonatal infections. GBS commonly colonizes the lower gastrointestinal and genital tracts and, during pregnancy, neonates are at risk of infection. Although intrapartum antibiotic prophylaxis during labor and delivery has decreased the incidence of early-onset neonatal infection, these measures do not prevent ascending infection that can occur earlier in pregnancy leading to preterm births, stillbirths, or late-onset neonatal infections. Prevention of GBS infection in pregnancy is complex and is likely influenced by multiple factors, including pathogenicity, host factors, vaginal microbiome, false-negative screening, and/or changes in antibiotic resistance. A deeper understanding of the mechanisms of GBS infections during pregnancy will facilitate the development of novel therapeutics and vaccines. Here, we summarize and discuss important advancements in our understanding of GBS vaginal colonization, ascending infection, and preterm birth.
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Affiliation(s)
- Jay Vornhagen
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kristina M Adams Waldorf
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
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10
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Differential transcription profiles of long non-coding RNAs in primary human brain microvascular endothelial cells in response to meningitic Escherichia coli. Sci Rep 2016; 6:38903. [PMID: 27958323 PMCID: PMC5153642 DOI: 10.1038/srep38903] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/15/2016] [Indexed: 12/29/2022] Open
Abstract
Accumulating studies have indicated the influence of long non-coding RNAs (lncRNAs) on various biological processes as well as disease development and progression. However, the lncRNAs involved in bacterial meningitis and their regulatory effects are largely unknown. By RNA-sequencing, the transcriptional profiles of host lncRNAs in primary human brain microvascular endothelial cells (hBMECs) in response to meningitic Escherichia coli were demonstrated. Here, 25,257 lncRNAs were identified, including 24,645 annotated lncRNAs and 612 newly found ones. A total of 895 lncRNAs exhibited significant differences upon infection, among which 382 were upregulated and 513 were downregulated (≥2-fold, p < 0.05). Via bioinformatic analysis, the features of these lncRNAs, their possible functions, and the potential regulatory relationships between lncRNAs and mRNAs were predicted. Moreover, we compared the transcriptional specificity of these differential lncRNAs among hBMECs, human astrocyte cell U251, and human umbilical vein endothelial cells, and demonstrated the novel regulatory effects of proinflammatory cytokines on these differential lncRNAs. To our knowledge, this is the first time the transcriptional profiles of host lncRNAs involved in E. coli-induced meningitis have been reported, which shall provide novel insight into the regulatory mechanisms behind bacterial meningitis involving lncRNAs, and contribute to better prevention and therapy of CNS infection.
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11
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Toledo A, Benach JL. Hijacking and Use of Host Lipids by Intracellular Pathogens. Microbiol Spectr 2015; 3:10.1128/microbiolspec.VMBF-0001-2014. [PMID: 27337282 PMCID: PMC5790186 DOI: 10.1128/microbiolspec.vmbf-0001-2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 12/14/2022] Open
Abstract
Intracellular bacteria use a number of strategies to survive, grow, multiply, and disseminate within the host. One of the most striking adaptations that intracellular pathogens have developed is the ability to utilize host lipids and their metabolism. Bacteria such as Anaplasma, Chlamydia, or Mycobacterium can use host lipids for different purposes, such as a means of entry through lipid rafts, building blocks for bacteria membrane formation, energy sources, camouflage to avoid the fusion of phagosomes and lysosomes, and dissemination. One of the most extreme examples of lipid exploitation is Mycobacterium, which not only utilizes the host lipid as a carbon and energy source but is also able to reprogram the host lipid metabolism. Likewise, Chlamydia spp. have also developed numerous mechanisms to reprogram lipids onto their intracellular inclusions. Finally, while the ability to exploit host lipids is important in intracellular bacteria, it is not an exclusive trait. Extracellular pathogens, including Helicobacter, Mycoplasma, and Borrelia, can recruit and metabolize host lipids that are important for their growth and survival.Throughout this chapter we will review how intracellular and extracellular bacterial pathogens utilize host lipids to enter, survive, multiply, and disseminate in the host.
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Affiliation(s)
- Alvaro Toledo
- Department of Molecular Genetics and Microbiology, Stony Brook University, Center for Infectious Diseases at the Center for Molecular Medicine, Stony Brook, NY 11794
| | - Jorge L Benach
- Department of Molecular Genetics and Microbiology, Stony Brook University, Center for Infectious Diseases at the Center for Molecular Medicine, Stony Brook, NY 11794
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12
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Jiang F, Waterfield N, Yang J, Yang G, Jin Q. A Pseudomonas aeruginosa Type VI Secretion Phospholipase D Effector Targets Both Prokaryotic and Eukaryotic Cells. Cell Host Microbe 2014; 15:600-10. [DOI: 10.1016/j.chom.2014.04.010] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/28/2014] [Accepted: 03/21/2014] [Indexed: 02/06/2023]
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13
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Lemire P, Houde M, Segura M. Encapsulated group BStreptococcusmodulates dendritic cell functions via lipid rafts and clathrin-mediated endocytosis. Cell Microbiol 2012; 14:1707-19. [DOI: 10.1111/j.1462-5822.2012.01830.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 06/13/2012] [Accepted: 06/19/2012] [Indexed: 01/26/2023]
Affiliation(s)
- Paul Lemire
- Laboratory of Immunology; Faculty of Veterinary Medicine; Université de Montréal; St-Hyacinthe; Quebec; Canada
| | - Mathieu Houde
- Laboratory of Immunology; Faculty of Veterinary Medicine; Université de Montréal; St-Hyacinthe; Quebec; Canada
| | - Mariela Segura
- Laboratory of Immunology; Faculty of Veterinary Medicine; Université de Montréal; St-Hyacinthe; Quebec; Canada
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14
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Streptococcus suis capsular polysaccharide inhibits phagocytosis through destabilization of lipid microdomains and prevents lactosylceramide-dependent recognition. Infect Immun 2011; 80:506-17. [PMID: 22124659 DOI: 10.1128/iai.05734-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Streptococcus suis type 2 is a major swine pathogen and a zoonotic agent, causing meningitis in both swine and humans. S. suis infects the host through the respiratory route, reaches the bloodstream, and persists until breaching into the central nervous system. The capsular polysaccharide (CPS) of S. suis type 2 is considered a key virulence factor of the bacteria. Though CPS allows S. suis to adhere to the membrane of cells of the immune system, it provides protection against phagocytosis. In fact, nonencapsulated mutants are easily internalized and killed by macrophages and dendritic cells. The objective of this work was to study the molecular mechanisms by which the CPS of S. suis prevents phagocytosis. By using latex beads covalently linked with purified CPS, it was shown that CPS itself was sufficient to inhibit entry of both latex beads and bystander fluorescent beads into macrophages. Upon contact with macrophages, encapsulated S. suis was shown to destabilize lipid microdomains at the cell surface, to block nitric oxide (NO) production during infection, and to prevent lactosylceramide accumulation at the phagocytic cup during infection. In contrast, the nonencapsulated mutant was easily internalized via lipid rafts, in a filipin-sensitive manner, leading to lactosylceramide recruitment and strong NO production. This is the first report to identify a role for CPS in lipid microdomain stability and to recognize an interaction between S. suis and lactosylceramide in phagocytes.
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Lucas EA, Billington SJ, Carlson P, McGee DJ, Jost BH. Phospholipase D promotes Arcanobacterium haemolyticum adhesion via lipid raft remodeling and host cell death following bacterial invasion. BMC Microbiol 2010; 10:270. [PMID: 20973961 PMCID: PMC2978216 DOI: 10.1186/1471-2180-10-270] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 10/25/2010] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Arcanobacterium haemolyticum is an emerging bacterial pathogen, causing pharyngitis and more invasive infections. This organism expresses an unusual phospholipase D (PLD), which we propose promotes bacterial pathogenesis through its action on host cell membranes. The pld gene is found on a genomic region of reduced %G + C, suggesting recent horizontal acquisition. RESULTS Recombinant PLD rearranged HeLa cell lipid rafts in a dose-dependent manner and this was inhibited by cholesterol sequestration. PLD also promoted host cell adhesion, as a pld mutant had a 60.3% reduction in its ability to adhere to HeLa cells as compared to the wild type. Conversely, the pld mutant appeared to invade HeLa cells approximately two-fold more efficiently as the wild type. This finding was attributable to a significant loss of host cell viability following secretion of PLD from intracellular bacteria. As determined by viability assay, only 15.6% and 82.3% of HeLa cells remained viable following invasion by the wild type or pld mutant, respectively, as compared to untreated HeLa cells. Transmission electron microscopy of HeLa cells inoculated with A. haemolyticum strains revealed that the pld mutant was contained within intracellular vacuoles, as compared to the wild type, which escaped the vacuole. Wild type-infected HeLa cells also displayed the hallmarks of necrosis. Similarly inoculated HeLa cells displayed no signs of apoptosis, as measured by induction of caspase 3/7, 8 or 9 activities. CONCLUSIONS These data indicate that PLD enhances bacterial adhesion and promotes host cell necrosis following invasion, and therefore, may be important in the disease pathogenesis of A. haemolyticum infections.
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Affiliation(s)
- Erynn A Lucas
- Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, AZ 85721, USA
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