Effect of rhamnolipids on permeability across Caco-2 cell monolayers.
OBJECTIVE
This report describes the effect of rhamnolipids (RLs), an amphiphilic biosurfactant produced by the bacterium Pseudomonas aeruginosa, on the integrity and permeability across Caco-2 cell monolayers.


METHODS
We measured the trans-epithelial electrical resistance (TEER) and permeability of [(14)C]mannitol across Caco-2 cell monolayers upon incubation with 0.01-5.0% v/v RLs as a function of incubation time (30, 60, 90, and 120 min). We also studied the recovery of RL-treated Caco-2 cell monolayers upon incubation with Kaempferol, which is a natural flavonoid that promotes the assembly of the tight junctions.


RESULTS
TEER of Caco-2 cell monolayers incubated with 0.01-5.0% v/v RLs solution dropped to 80-28% of that of untreated cells. Decline in TEER was associated with an increase in [(14)C]mannitol permeability as a function of RLs concentration and incubation time with Caco-2 cells. Incubation of RLs-treated Caco-2 cell monolayers with normal culture medium for 48 h did not restore barrier integrity. Whereas, incubation of a RLs-treated Caco-2 cells with culture medium containing Kaempferol for 24 h restored barrier function indicated by the higher TEER and lower [(14)C]mannitol permeability values.


CONCLUSIONS
These results show the ability of RLs to modulate the integrity and permeability of Caco-2 cell monolayers in a concentration- and time-dependent fashion, which suggest their potential to function as a non-toxic permeation enhancer.
Department of Biomedical Engineering Cellular Engineering & Nano-Therapeutics Laboratory College of Engineering, University of Michigan, Ann Arbor, Michigan, 48109, USA.
Charity J
CJ
Wallace
Scott H
SH
Medina
Mohamed E H
ME
ElSayed
D018938:Caco-2 Cells; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology*; D006017:Glycolipids / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D044949:Kaempferols / Q000494:pharmacology; D010539:Permeability / Q000187:drug effects; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*
D006017:Glycolipids; D044949:Kaempferols; C418382:rhamnolipid; C006552:kaempferol