scholarly journals Hcp Family Proteins Secreted via the Type VI Secretion System Coordinately Regulate Escherichia coli K1 Interaction with Human Brain Microvascular Endothelial Cells

2011 ◽  
Vol 80 (3) ◽  
pp. 1243-1251 ◽  
Author(s):  
Yan Zhou ◽  
Jing Tao ◽  
Hao Yu ◽  
Jinjing Ni ◽  
Lingbing Zeng ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Human Brain ◽  
Microvascular Endothelial Cells ◽  
Dependent Manner ◽  
Brain Microvascular Endothelial Cells ◽  
Content Type ◽  
E Coli ◽  
Type Vi Secretion ◽  
Microvascular Endothelial ◽  
Cytoskeleton Rearrangement

Type VI secretion systems (T6SSs) are involved in the pathogenicity of several Gram-negative bacteria. Based on sequence analysis, we found that a cluster ofEscherichia colivirulencefactors (EVF) encoding a putative T6SS exists in the genome of the meningitis-causingE. coliK1 strain RS218. The T6SS-associated deletion mutants exhibited significant defects in binding to and invasion of human brain microvascular endothelial cells (HBMEC) compared with the parent strain. Hcp family proteins (the hallmark of T6SS), including Hcp1 and Hcp2, were localized in the bacterial outer membrane, but the involvements of Hcp1 and Hcp2 have been shown to differ inE. coli-HBMEC interaction. The deletion mutant ofhcp2showed defects in the bacterial binding to and invasion of HBMEC, while Hcp1 was secreted in a T6SS-dependent manner and induced actin cytoskeleton rearrangement, apoptosis, and the release of interleukin-6 (IL-6) and IL-8 in HBMEC. These findings demonstrate that the T6SS is functional inE. coliK1, and two Hcp family proteins participate in different steps ofE. coliinteraction with HBMEC in a coordinate manner, e.g., binding to and invasion of HBMEC, the cytokine and chemokine release followed by cytoskeleton rearrangement, and apoptosis in HBMEC. This is the first demonstration of the role of T6SS in meningitis-causingE. coliK1, and T6SS-associated Hcp family proteins are likely to contribute to the pathogenesis ofE. colimeningitis.

scholarly journals Application of Signature-Tagged Mutagenesis for Identification ofEscherichia coli K1 Genes That Contribute to Invasion of Human Brain Microvascular Endothelial Cells

2000 ◽  
Vol 68 (9) ◽  
pp. 5056-5061 ◽  
Author(s):  
Julie L. Badger ◽  
Carol A. Wass ◽  
Scott J. Weissman ◽  
Kwang Sik Kim
Keyword(s):  
Endothelial Cells ◽  
Human Brain ◽  
Neonatal Rat ◽  
Microvascular Endothelial Cells ◽  
Selection Strategy ◽  
Bacterial Invasion ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli ◽  
Microvascular Endothelial

ABSTRACT Escherichia coli K1 is the leading cause of gram-negative bacterial meningitis in neonates. It is principally due to our limited understanding of the pathogenesis of this disease that the morbidity and mortality rates remain unacceptably high. To identify genes required for E. coli K1 penetration of the blood-brain barrier (BBB), we used the negative selection strategy of signature-tagged transposon mutagenesis (STM) to screen mutants for loss or decreased invasion of human brain microvascular endothelial cells (HBMEC) which comprise the BBB. A total of 3,360 insertion mutants of E. coli K1 were screened, and potential HBMEC invasion mutants were subjected to a secondary invasion screen. Those mutants that failed to pass the serial invasion screens were then tested individually. Seven prototrophic mutants were found to exhibit significantly decreased invasive ability in HBMEC. We identifiedtraJ and five previously uncharacterized loci whose gene products are necessary for HBMEC invasion by E. coli K1. In addition, cnf1, a gene previously shown to play a role in bacterial invasion, was identified. More importantly, atraJ mutant was attenuated in penetration of the BBB in the neonatal rat model of experimental hematogenous meningitis. This is the first in vivo demonstration that traJ is involved in the pathogenesis of E. coli K1 meningitis.

OxLDL Inhibits Brain Angiogenesis in Dose Dependent Manner via Reducing Level of VEGF and Angiopoietin-2: A Comprehensive Study

2017 ◽  
Author(s):  
Tasneem Alniqrish ◽  
Saed Khawaldeh
Keyword(s):  
Endothelial Cells ◽  
Human Brain ◽  
Angiogenic Factor ◽  
Microvascular Endothelial Cells ◽  
Dependent Manner ◽  
Brain Microvascular Endothelial Cells ◽  
Wide Range ◽  
Microvascular Endothelial ◽  
Dose Dependent ◽  
Brain Angiogenesis

Hyperlipidemia is recognized as a major health problem worldwide, moreover, it is considered as a major risk factor for cardiovascular and cerebrovascular diseases development. Since the majority of studies were performed to investigate the effect of hyperlipidemia on the angiogenesis of peripheral derived endothelial cell, this study aims to assess the effect of hyperlipidemia on the angiogenic response of human brain cells in a fast, easy and inexpensive method. Furthermore, it aims also to assess the involvement of Vascular Endothelial Growth Factor (VEGF) and angiopoietin. To achieve this aim, human Brain Microvascular Endothelial Cells (hBMECs) were treated with different concentration of Oxidized Low Density Lipoprotein (OxLDL) (1-100 μg/ml) for 24 hours. Migration rate and tube formation as markers of angiogenesis were performed, also Coomassie blue was used to detect protein level. OxLDL was found to inhibit brain angiogenesis in dose dependent manner over a wide range of concentrations (1-100 μg/ml). Using 1 μg/ml of OxLDL made minimum reduction of 10% whereas using 100 μg/ml of OxLDL resulted 70-80% reduction in the angiogenic potential of hBMECs within 24 hours. Moreover, OxLDL mediated its effect through reduced VEGF level and this effect was partially reversed by administered 5 ng/ml of VEGF. Additionally, OxLDL reduced the level of angiopoitin-2. This further supports the assumption that OxLDL has an anti-angiogenic effect in hBMECs and surely in the brain also. As a conclusion, OxLDL inhibits brain angiogenesis in dose dependent manner through reducing the level of angiogenic factor in human brain microvascular endothelial cells. We achieved our goal of having a preliminary indicator of brain angiogenesis under hyperlipidemia by using a simple but well-developed technique that incorporated the minimal number of tests and the cheapest.

scholarly journals Effects of ompA Deletion on Expression of Type 1 Fimbriae in Escherichia coli K1 Strain RS218 and on the Association of E. coli with Human Brain Microvascular Endothelial Cells

2006 ◽  
Vol 74 (10) ◽  
pp. 5609-5616 ◽  
Author(s):  
Ching-Hao Teng ◽  
Yi Xie ◽  
Sooan Shin ◽  
Francescopaolo Di Cello ◽  
Maneesh Paul-Satyaseela ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Human Brain ◽  
Microvascular Endothelial Cells ◽  
Mrna Levels ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Microvascular Endothelial

ABSTRACT We have previously shown that outer membrane protein A (OmpA) and type 1 fimbriae are the bacterial determinants involved in Escherichia coli K1 binding to human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. In investigating the role of OmpA in E. coli K1 binding to HBMEC, we showed for the first time that ompA deletion decreased the expression of type 1 fimbriae in E. coli K1. Decreased expression of type 1 fimbriae in the ompA deletion mutant was largely the result of driving the fim promoter toward the type 1 fimbrial phase-OFF orientation. mRNA levels of fimB and fimE were found to be decreased with the OmpA mutant compared to the parent strain. Of interest, the ompA deletion further decreased the abilities of E. coli K1 to bind to and invade HBMEC under the conditions of fixing type 1 fimbria expression in the phase-ON or phase-OFF status. These findings suggest that the decreased ability of the OmpA mutant to interact with HBMEC is not entirely due to its decreased type 1 fimbrial expression and that OmpA and type 1 fimbriae facilitate the interaction of E. coli K1 with HBMEC at least in an additive manner.

scholarly journals NlpI Contributes to Escherichia coli K1 Strain RS218 Interaction with Human Brain Microvascular Endothelial Cells

2010 ◽  
Vol 78 (7) ◽  
pp. 3090-3096 ◽  
Author(s):  
Ching-Hao Teng ◽  
Yu-Ting Tseng ◽  
Ravi Maruvada ◽  
Donna Pearce ◽  
Yi Xie ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Human Brain ◽  
Neonatal Meningitis ◽  
Microvascular Endothelial Cells ◽  
Growth Defect ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli ◽  
Microvascular Endothelial ◽  
K 12

ABSTRACT Escherichia coli K1 is the most common Gram-negative bacillary organism causing neonatal meningitis. E. coli K1 binding to and invasion of human brain microvascular endothelial cells (HBMECs) is a prerequisite for its traversal of the blood-brain barrier (BBB) and penetration into the brain. In the present study, we identified NlpI as a novel bacterial determinant contributing to E. coli K1 interaction with HBMECs. The deletion of nlpI did not affect the expression of the known bacterial determinants involved in E. coli K1-HBMEC interaction, such as type 1 fimbriae, flagella, and OmpA, and the contribution of NlpI to HBMECs binding and invasion was independent of those bacterial determinants. Previous reports have shown that the nlpI mutant of E. coli K-12 exhibits growth defect at 42°C at low osmolarity, and its thermosensitive phenotype can be suppressed by a mutation on the spr gene. The nlpI mutant of strain RS218 exhibited similar thermosensitive phenotype, but additional spr mutation did not restore the ability of the nlpI mutant to interact with HBMECs. These findings suggest the decreased ability of the nlpI mutant to interact with HBMECs is not associated with the thermosensitive phenotype. NlpI was determined as an outer membrane-anchored protein in E. coli, and the nlpI mutant was defective in cytosolic phospholipase A2α (cPLA2α) phosphorylation compared to the parent strain. These findings illustrate the first demonstration of NlpI's contribution to E. coli K1 binding to and invasion of HBMECs, and its contribution is likely to involve cPLA2α.

scholarly journals Escherichia coli K1 RS218 Interacts with Human Brain Microvascular Endothelial Cells via Type 1 Fimbria Bacteria in the Fimbriated State

2005 ◽  
Vol 73 (5) ◽  
pp. 2923-2931 ◽  
Author(s):  
Ching-Hao Teng ◽  
Mian Cai ◽  
Sooan Shin ◽  
Yi Xie ◽  
Kee-Jun Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Human Brain ◽  
Neonatal Meningitis ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli ◽  
Microvascular Endothelial

ABSTRACT Escherichia coli K1 is a major gram-negative organism causing neonatal meningitis. E. coli K1 binding to and invasion of human brain microvascular endothelial cells (HBMEC) are a prerequisite for E. coli penetration into the central nervous system in vivo. In the present study, we showed using DNA microarray analysis that E. coli K1 associated with HBMEC expressed significantly higher levels of the fim genes compared to nonassociated bacteria. We also showed that E. coli K1 binding to and invasion of HBMEC were significantly decreased with its fimH deletion mutant and type 1 fimbria locked-off mutant, while they were significantly increased with its type 1 fimbria locked-on mutant. E. coli K1 strains associated with HBMEC were predominantly type 1 fimbria phase-on (i.e., fimbriated) bacteria. Taken together, we showed for the first time that type 1 fimbriae play an important role in E. coli K1 binding to and invasion of HBMEC and that type 1 fimbria phase-on E. coli is the major population interacting with HBMEC.

scholarly journals IbeA and OmpA of Escherichia coli K1 Exploit Rac1 Activation for Invasion of Human Brain Microvascular Endothelial Cells

2012 ◽  
Vol 80 (6) ◽  
pp. 2035-2041 ◽  
Author(s):  
Ravi Maruvada ◽  
Kwang Sik Kim
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Human Brain ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Content Type ◽  
E Coli ◽  
Blood Brain

ABSTRACTMeningitis-causingEscherichia coliK1 internalization of the blood-brain barrier is required for penetration into the brain, but the host-microbial interactions involved inE. colientry of the blood-brain barrier remain incompletely understood. We show here that a meningitis-causingE. coliK1 strain RS218 activates Rac1 (GTP-Rac1) of human brain microvascular endothelial cells (HBMEC) in a time-dependent manner. Both activation and bacterial invasion were significantly inhibited in the presence of a Rac1 inhibitor. We further showed that the guanine nucleotide exchange factor Vav2, not β-Pix, was involved inE. coliK1-mediated Rac1 activation. Since activated STAT3 is known to bind GTP-Rac1, the relationship between STAT3 and Rac1 was examined inE. coliK1 invasion of HBMEC. Downregulation of STAT3 resulted in significantly decreasedE. coliinvasion compared to control HBMEC, as well as a corresponding decrease in GTP-Rac1, suggesting that Rac1 activation in response toE. coliis under the control of STAT3. More importantly, twoE. colideterminants contributing to HBMEC invasion, IbeA and OmpA, were shown to affect both Rac1 activation and their association with STAT3. These findings demonstrate for the first time that specificE. colideterminants regulate a novel mechanism of STAT3 cross talk with Rac1 inE. coliK1 invasion of HBMEC.

scholarly journals Ubiquinone Metabolism and Transcription HIF-1 Targets Pathway Are Toxicity Signature Pathways Present in Extracellular Vesicles of Paraquat-Exposed Human Brain Microvascular Endothelial Cells

2021 ◽  
Vol 22 (10) ◽  
pp. 5065
Author(s):  
Tatjana Vujić ◽  
Domitille Schvartz ◽  
Anton Iliuk ◽  
Jean-Charles Sanchez
Keyword(s):  
Endothelial Cells ◽  
Human Brain ◽  
Extracellular Vesicles ◽  
Physiological State ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Cell Of Origin ◽  
Functional Changes ◽  
Data Independent Acquisition ◽  
Microvascular Endothelial

Over the last decade, the knowledge in extracellular vesicles (EVs) biogenesis and modulation has increasingly grown. As their content reflects the physiological state of their donor cells, these “intercellular messengers” progressively became a potential source of biomarker reflecting the host cell state. However, little is known about EVs released from the human brain microvascular endothelial cells (HBMECs). The current study aimed to isolate and characterize EVs from HBMECs and to analyze their EVs proteome modulation after paraquat (PQ) stimulation, a widely used herbicide known for its neurotoxic effect. Size distribution, concentration and presence of well-known EV markers were assessed. Identification and quantification of PQ-exposed EV proteins was conducted by data-independent acquisition mass spectrometry (DIA-MS). Signature pathways of PQ-treated EVs were analyzed by gene ontology terms and pathway enrichment. Results highlighted that EVs exposed to PQ have modulated pathways, namely the ubiquinone metabolism and the transcription HIF-1 targets. These pathways may be potential molecular signatures of the PQ-induced toxicity carried by EVs that are reflecting their cell of origin by transporting with them irreversible functional changes.

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