Copper treatment alters the permeability of tight junctions in cultured human intestinal Caco-2 cells.
The effects of copper on tight-junction permeability were investigated in human intestinal Caco-2 cells, monitoring transepithelial electrical resistance and transepithelial passage of mannitol. Apical treatment of Caco-2 cells with 10-100 microM CuCl(2) (up to 3 h) produced a time- and concentration-dependent increase in tight-junction permeability, reversible after 24 h in complete medium in the absence of added copper. These effects were not observed in cells treated with copper complexed to L-histidine [Cu(His)(2)]. The copper-induced increase in tight-junction permeability was affected by the pH of the apical medium, as was the apical uptake of (64)CuCl(2), both exhibiting a maximum at pH 6.0. Treatment with CuCl(2) produced a concentration-dependent reduction in the staining of F actin but not of the junctional proteins zonula occludens-1, occludin, and E-cadherin and produced ultrastructural alterations to microvilli and tight junctions that were not observed after treatment with up to 200 microM Cu(His)(2) for 3 h. Overall, these data point to an intracellular effect of copper on tight junctions, mediated by perturbations of the F actin cytoskeleton.
Ferruzza
S
S
Istituto Nazionale della Nutrizione, 00178 Rome, Università di Roma Tor Vergata, 00133 Rome, Italy.
Scarino
M L
ML
Rotilio
G
G
Ciriolo
M R
MR
Santaroni
P
P
Muda
A O
AO
Sambuy
Y
Y
D000199:Actins / Q000502:physiology; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D003300:Copper / Q000493:pharmacokinetics*; D003513:Cycloheximide / Q000494:pharmacology; D017097:Electric Impedance; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D006639:Histidine / Q000493:pharmacokinetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012235:Rhodamines; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure
D000199:Actins; D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D011500:Protein Synthesis Inhibitors; D012235:Rhodamines; C045576:copper bis(histidinate); C009434:tetramethylrhodamine isothiocyanate; D006639:Histidine; D003300:Copper; D003513:Cycloheximide; C029892:cupric chloride