Activation of AMP-Activated Protein Kinase by a Plant-Derived Dihydroisosteviol in Human Intestinal Epithelial Cell
2013
: Our previous study has shown that dihydroisosteviol (DHIS), a derivative of stevioside isolated from Stevia rebaudiana (Bertoni), inhibits cystic fibrosis transmembrane conductance regulator (CFTR)-mediated transepithelial chloride secretion across monolayers of human intestinal epithelial (T84) cells and prevents cholera toxin-induced intestinal fluid secretion in mouse closed loop models. In this study, we aimed to investigate a mechanism by which DHIS inhibits CFTR activity. Apical chloride current measurements in Fisher rat thyroid cells stably transfected with wild-type human CFTR (FRT-CFTR cells) and T84 cells were used to investigate mechanism of CFTR inhibition by DHIS. In addition, effect of DHIS on AMP-activated protein kinase (AMPK) activation was investigated using Western blot analysis. Surprisingly, it was found that DHIS failed to inhibit CFTR-mediated apical chloride current in FRT-CFTR cells. In contrast, DHIS effectively inhibited CFTR-mediated apical chloride current induced by a cell permeable cAMP analog CPT-cAMP and a direct CFTR activator genistein in T84 cell monolayers. Interestingly, this inhibitory effect of DHIS on CFTR was significantly (p<0.05) reduced by pretreatment with compound C, an AMPK inhibitor. AICAR, a known AMPK activator, was able to inhibit CFTR activity in both FRT-CFTR and T84 cells. Western blot analysis showed that DHIS induced AMPK activation in T84 cells, but not in FRT-CFTR cells. Our results indicate that DHIS inhibits CFTR-mediated chloride secretion in T84 cells, in part, by activation of AMPK activity. DHIS therefore represents a novel candidate of AMPK activators.
Keywords:
- MAP2K7
- Protein kinase A
- ASK1
- Cyclin-dependent kinase 9
- Mitogen-activated protein kinase kinase
- Cyclin-dependent kinase 2
- cGMP-dependent protein kinase
- MAP kinase kinase kinase
- Biochemistry
- Biology
- Activator (genetics)
- AMPK
- stevia rebaudiana
- Cystic fibrosis transmembrane conductance regulator
- Chloride channel
- AMP-activated protein kinase
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
21
References
8
Citations
NaN
KQI