Protein kinase C enhances tight junction barrier function of human nasal epithelial cells in primary culture by transcriptional regulation.
The epithelium of upper respiratory tissues such as human nasal mucosa forms a continuous barrier via tight junctions, which is thought to be regulated in part through a protein kinase C (PKC) signaling pathway. To investigate the mechanisms of the regulation of PKC-mediated tight junction barrier function of human nasal epithelium in detail, primary human nasal epithelial cells were treated with the PKC activator 12-O-tetradecanoylophorbol-13-acetate (TPA). In primary human nasal epithelial cells, treatment with TPA led not only to activation of phosphorylation of PKC, myristoylated alanine-rich C kinase substrate, and mitogen-activated protein kinase but also expression of novel PKC-delta, PKC-theta, and PKC-epsilon. Treatment with TPA increased transepithelial electrical resistance, with tight junction barrier function more than 4-fold that of the control, together with up-regulation of tight junction proteins, occludin, zona occludens (ZO)-1, ZO-2 and claudin-1 at the transcriptional level. Furthermore, it affected the subcellular localization of the tight junction proteins and the numbers of tight junction strands. The up-regulation of barrier function and tight junction proteins was prevented by a pan-PKC inhibitor, and the inhibitors of PKC-delta and PKC-theta but not PKC-epsilon. In primary human nasal epithelial cells, transcriptional factors GATA-3 and -6 were detected by reverse transcription-polymerase chain reaction. The knockdown of GATA-3 using RNA interference resulted in inhibition of up-regulation of ZO-1 and ZO-2 by treatment with TPA. These results suggest that TPA-induced PKC signaling enhances the barrier function of human nasal epithelial cells via transcriptional up-regulation of tight junction proteins, and the mechanisms may contribute to a drug delivery system.
Koizumi
Jun-ichi
J
Department of Otolaryngology, Sapporo Medical University School of Medicine, S1. W17. Sapporo 060-8556, Japan.
Kojima
Takashi
T
Ogasawara
Noriko
N
Kamekura
Ryuta
R
Kurose
Makoto
M
Go
Mitsuru
M
Harimaya
Atsushi
A
Murata
Masaki
M
Osanai
Makoto
M
Chiba
Hideki
H
Himi
Tetsuo
T
Sawada
Norimasa
N
D002478:Cells, Cultured; D006801:Humans; D009297:Nasal Mucosa / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D019108:Tight Junctions / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology*
D011493:Protein Kinase C