Published online Apr 21, 2015. doi: 10.3748/wjg.v21.i15.4547
Peer-review started: September 21, 2014
First decision: October 19, 2014
Revised: December 7, 2014
Accepted: January 8, 2015
Article in press: January 8, 2015
Published online: April 21, 2015
AIM: To investigate the influence of lipopolysaccharide (LPS) through the p38/c-Jun N-terminal kinase (JNK) signalling pathway on aquaporin 3 (AQP3) expression in HT-29 human colon epithelial cells.
METHODS: HT-29 cells were treated with LPS, and then the membrane localisation of AQP3 was examined by immunofluorescence staining. The mRNA and protein expression of AQP3 with LPS exposure was measured by real-time reverse transcription-PCR and Western blot, respectively. Activation of p38 and JNK was evaluated by detection of phosphorylation of p38 and JNK using Western blot assay. AQP3 protein expression was determined by Western blot in cells after treatment with SB203580, a selective p38 MAPK inhibitor, or SP600125, a selective JNK inhibitor.
RESULTS: In HT-29 cells, the transcription and protein expression of AQP3 were decreased by LPS in a dose- and time-dependent manner, the expression of AQP3 was significantly decreased with the increased concentration of LPS, and at a dose of 100 μg/mL LPS, AQP3 mRNA and protein levels were decreased by a maximum (P < 0.05) of 1.51-fold and 1.49-fold, respectively. When cells were treated with 100 μg/mL LPS for 0, 3, 6, 12, and 24 h, the AQP3 mRNA level was significantly decreased at an early time point of 3 h, and reached about 10% of the control level at 24 h post-treatment (P < 0.05). Down-regulation of AQP3 expression was significantly inhibited by the p38 inhibitor (SB203580) and JNK inhibitor (SP600125).
CONCLUSION: p38 and JNK may be promising targets for the preservation of AQP3 expression and may be beneficial to the clinical management of diarrhoea.
Core tip: In this study we investigated the mRNA and protein expression levels of aquaporin 3 (AQP3) in HT-29 cells exposed to lipopolysaccharide. In addition, we examined the mechanism of regulation of AQP3 expression via the p38 and JNK signalling pathway in vitro.