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 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 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 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.

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 Decrease of miR-19b-3p in Brain Microvascular Endothelial Cells Attenuates Meningitic Escherichia coli-Induced Neuroinflammation via TNFAIP3-Mediated NF-κB Inhibition

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 268 ◽  
Author(s):  
Amjad ◽  
Yang ◽  
Li ◽  
Fu ◽  
Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Endothelial Cells ◽  
Negative Regulator ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
E Coli ◽  
Inflammatory Damage ◽  
Microvascular Endothelial

Meningitic Escherichia coli can traverse the host’s blood–brain barrier (BBB) and induce severe neuroinflammatory damage to the central nervous system (CNS). During this process, the host needs to reasonably balance the battle between bacteria and brain microvascular endothelial cells (BMECs) to minimize inflammatory damage, but this quenching of neuroinflammatory responses at the BBB is unclear. MicroRNAs (miRNAs) are widely recognized as key negative regulators in many pathophysiological processes, including inflammatory responses. Our previous transcriptome sequencing revealed numbers of differential miRNAs in BMECs upon meningitic E. coli infection; we next sought to explore whether and how these miRNAs worked to modulate neuroinflammatory responses at meningitic E. coli entry of the BBB. Here, we demonstrated in vivo and in vitro that meningitic E. coli infection of BMECs significantly downregulated miR-19b-3p, which led to attenuated production of proinflammatory cytokines and chemokines via increasing the expression of TNFAIP3, a negative regulator of NF-κB signaling. Moreover, in vivo injection of miR-19b-3p mimics during meningitic E. coli challenge further aggravated the inflammatory damage to mice brains. These in vivo and in vitro findings indicate a novel quenching mechanism of the host by attenuating miR-19b-3p/TNFAIP3/NF-κB signaling in BMECs in response to meningitic E. coli, thus preventing CNS from further neuroinflammatory damage.

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