Table 2:

Inducible Airway Epithelial Barrier Disruption by Air Pollutants and Respiratory Viruses

Stimulus	Cells	TEER	Permeability (Tracer)	AJC expression	Notes	Reference
Air pollution
Ozone (0.5–0.8 ppm)	CBE	Decreased	Increased (mannitol)	ND		136
Ozone (0.1–0.4 ppm)	PBEC	Decreased	Increased (BSA)	ND	More in asthmatics	137
MWCNT (100 μg/ml)	Calu-3	Decreased	Increased (mannitol)	ND		138
DEP (125 μg/ml)	16HBElo−	Decreased	ND	Slight decrease membrane occludin		139
Ambient PM10 (50 μg/cm2) DEP	A549 Rat AlvEC	Decreased	Increased	Decreased membrane occludin by WB and IF	Possible cytotoxicity; mitochondrial ROS-dependent	140
Ambient PM (150 μg/ml)	NHBEC	ND	Increased (4 kD dextran)	No change in β-catenin	Required 2 applications, unless septin-2 knocked-down	16
Respiratory viruses
Rhinovirus (RV39, RV1B, MOI = 1)	PTEC 16HBElo−	Decreased	Increased (FITC-inulin)	ZO-1 dissociation from AJC	Independent of IL-1β, TNF-α, and IFN-γ; increased translocation of apical bacteria; blocked by DPI	141, 142
RSV (A2, 2.5–5)	PBEC A549	Decreased	ND	Cytoskeletal rearrangement	Dependent on MAPK	143
RSV (A2, MOI = 0.05–1)	16HBElo−	Decreased	Increased (3 kD dextran)	Expression-independent AJC disassembly	Dependent on sustained PKD activation	108

Definition of abbreviations: AJC, apical junctional complexes; CBE, canine bronchial epithelial cells; DEP, diesel exhaust particles; DPI, diphenylene iodonium; IF, immunofluorescence; MAPK, mitogen-associated protein kinases; MOI, multiplicity of infection; MWCNT, multiwalled carbon nanotubes; ND, not determined; NHBE, normal human bronchial epithelial cells; PKD, protein kinase D; PM, particulate matter; PM₁₀, particulate matter < 10 μm in diameter; PBEC, primary bronchial epithelial cells; PTEC, primary tracheal epithelial cells; ROS, reactive oxygen species; RSV, respiratory syncytial virus; WB, Western blot.