Heterologous regulation of anion transporters by menthol in human airway epithelial cells.
The present study concerns previously unreported effects of menthol, a cyclic terpene alcohol produced by the peppermint herb, on anion transporters in polarized human airway Calu-3 epithelia. Application of menthol (0.01-1mM) attenuated transepithelial anion transport, estimated as short-circuit currents (I(SC)), after stimulation by forskolin (10microM) but not before. In contrast, menthol potentiated forskolin-stimulated and -unstimulated apical Cl(-) conductance, which reflected the cystic fibrosis transmembrane conductance regulator (CFTR: the cAMP-regulated Cl(-) channel)-mediated conductance, without correlation to changes in cytosolic cAMP levels. These results indicate that menthol-induced attenuation of forskolin-induced I(SC) despite CFTR up-regulation was due to cAMP-independent inhibition of basolateral anion uptake, which is the rate-limiting step for transepithelial anion transport. Analyses of the responsible basolateral anion transporters revealed that forskolin increased both bumetanide (an inhibitor of the basolateral Na(+)-K(+)-2Cl(-) cotransporter [NKCC1])- and DNDS (an inhibitor of basolateral HCO(3)(-)-dependent anion transporters [NBC1/AE2])-sensitive I(SC) in the control whereas only the former was prevented by the application of menthol. Neither the bumetanide- nor DNDS-sensitive component was, however, reduced by menthol without forskolin. These heterologous effects of menthol were reproduced by latrunculin B, an inhibitor of actin polymerization. F-actin staining showed that menthol prevented forskolin-stimulated rearrangements of actin microfilaments without affecting the distribution of forskolin-unstimulated microfilaments. Collectively, menthol functions as an activator of CFTR and prevents activation of NKCC1 without affecting NBC1/AE although all of these transporters are commonly cAMP-dependent. The heterologous effects may be mediated by the actin cytoskeleton, which interacts with CFTR and NKCC1.
Morise
Masahiro
M
Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Ito
Yasushi
Y
Matsuno
Tadakatsu
T
Hibino
Yoshitaka
Y
Mizutani
Takefumi
T
Ito
Satoru
S
Hashimoto
Naozumi
N
Kondo
Masashi
M
Imaizumi
Kazuyoshi
K
Hasegawa
Yoshinori
Y
D000199:Actins / Q000737:chemistry / Q000378:metabolism; D027321:Anion Transport Proteins / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D016764:Cell Polarity; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D008610:Menthol / Q000494:pharmacology*; D015203:Reproducibility of Results; D012137:Respiratory System / Q000166:cytology*; D053778:Thiazolidines / Q000494:pharmacology
D000199:Actins; D027321:Anion Transport Proteins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D053778:Thiazolidines; D008610:Menthol; D005576:Colforsin; D000242:Cyclic AMP; C037068:latrunculin B