An Investigation into the Effects of Outer Membrane Vesicles and Lipopolysaccharide of Porphyromonas gingivalis on Blood-Brain Barrier Integrity, Permeability, and Disruption of Scaffolding Proteins in a Human in vitro Model

Background: The effects of the key pathogens and virulence factors associated with gum disease such as Porphyromonas gingivalis (P. gingivalis) on the central nervous system is of great interest with respect to development of neuropathologies and hence therapeutics and preventative strategies. Chronic infections and associated inflammation are known to weaken the first line of defense for the brain, the blood-brain barrier (BBB). Objective: The focus of this study is to utilize an established human in vitro BBB model to evaluate the effects of P. gingivalis virulence factors lipopolysaccharide (LPS) and outer membrane vesicles (OMVs) on a primary-derived human model representing the neurovascular unit of the BBB. Methods: Changes to the integrity of the BBB after application of P. gingivalis LPS and OMVs were investigated and correlated with transport of LPS. Additionally, the effect of P. gingivalis LPS and OMVs on human brain microvascular endothelial cells in monolayer was evaluated using immunofluorescence microscopy. Results: The integrity of the BBB model was weakened by application of P. gingivalis LPS and OMVs, as measured by a decrease in electrical resistance and a recovery deficit was seen in comparison to the controls. Application of P. gingivalis OMVs to a monoculture of human brain microvascular endothelial cells showed disruption of the tight junction zona occludens protein (ZO-1) compared to controls. Conclusion: These findings show that the integrity of tight junctions of the human BBB could be weakened by association with P. gingivalis virulence factors LPS and OMVs containing proteolytic enzymes (gingipains).

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Human Brain Microvascular Endothelial Cells and Umbilical Vein Endothelial Cells Differentially Facilitate Leukocyte Recruitment and Utilize Chemokines for T Cell Migration

Clinical and Developmental Immunology ◽

10.1155/2008/384982 ◽

2008 ◽

Vol 2008 ◽

pp. 1-8 ◽

Cited By ~ 44

Author(s):

Shumei Man ◽

Eroboghene E. Ubogu ◽

Katherine A. Williams ◽

Barbara Tucky ◽

Melissa K. Callahan ◽

...

Keyword(s):

Endothelial Cells ◽

Cell Migration ◽

T Cell ◽

Human Brain ◽

Umbilical Vein ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

T Cell Migration ◽

Umbilical Vein Endothelial Cells

Endothelial cells that functionally express blood brain barrier (BBB) properties are useful surrogates for studying leukocyte-endothelial cell interactions at the BBB. In this study, we compared two different endothelial cellular models: transfected human brain microvascular endothelial cells (THBMECs) and human umbilical vein endothelial cells (HUVECs). With each grow under optimal conditions, confluent THBMEC cultures showed continuous occludin and ZO-1 immunoreactivity, while HUVEC cultures exhibited punctate ZO-1 expression at sites of cell-cell contact only. Confluent THBMEC cultures on 24-well collagen-coated transwell inserts had significantly higher transendothelial electrical resistance (TEER) and lower solute permeability than HUVECs. Confluent THBMECs were more restrictive for mononuclear cell migration than HUVECs. Only THBMECs utilized abluminal CCL5 to facilitate T-lymphocyte migration in vitro although both THBMECs and HUVECs employed CCL3 to facilitate T cell migration. These data establish baseline conditions for using THBMECs to develop in vitro BBB models for studying leukocyte-endothelial interactions during neuroinflammation.

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Single Domain Antibodies Targeting Receptor Binding Pockets of NadA Restrain Adhesion of Neisseria meningitidis to Human Brain Microvascular Endothelial Cells

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2020.573281 ◽

2020 ◽

Vol 7 ◽

Author(s):

Amod Kulkarni ◽

Evelína Mochnáčová ◽

Petra Majerova ◽

Ján Čurlík ◽

Katarína Bhide ◽

...

Keyword(s):

Endothelial Cells ◽

Phage Display ◽

Human Brain ◽

Receptor Binding ◽

Phage Library ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

Binding Pockets ◽

Microvascular Endothelial

Neisseria adhesin A (NadA), one of the surface adhesins of Neisseria meningitides (NM), interacts with several cell types including human brain microvascular endothelial cells (hBMECs) and play important role in the pathogenesis. Receptor binding pockets of NadA are localized on the globular head domain (A33 to K69) and the first coiled-coil domain (L121 to K158). Here, the phage display was used to develop a variable heavy chain domain (VHH) that can block receptor binding sites of recombinant NadA (rec-NadA). A phage library displaying VHH was panned against synthetic peptides (NadA-gdA33−K69 or NadA-ccL121−K158), gene encoding VHH was amplified from bound phages and re-cloned in the expression vector, and the soluble VHHs containing disulfide bonds were overexpressed in the SHuffle E. coli. From the repertoire of 96 clones, two VHHs (VHHF3–binding NadA-gdA33−K69 and VHHG9–binding NadA-ccL121−K158) were finally selected as they abrogated the interaction between rec-NadA and the cell receptor. Preincubation of NM with VHHF3 and VHHG9 significantly reduced the adhesion of NM on hBMECs in situ and hindered the traversal of NM across the in-vitro BBB model. The work presents a phage display pipeline with a single-round of panning to select receptor blocking VHHs. It also demonstrates the production of soluble and functional VHHs, which blocked the interaction between NadA and its receptor, decreased adhesion of NM on hBMECs, and reduced translocation of NM across BBB in-vitro. The selected NadA blocking VHHs could be promising molecules for therapeutic translation.

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