Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA089

Poster Communications

Regulation of Gap Junction Coupling in Large Intestine Epithelial Cells by Adenosine Signalling

A. Klett1, A. Bader1, A. Becker1, A. Ngezahayo1,2

1. Institute of Biophysics, Leibniz University Hannover, Hanover, Germany. 2. Center for Systems Neuroscience (ZSN), University of Veterinary Medicine Hanover, Hanover, Germany.

The colon epithelial cell line Caco-2 was used to analyse the role of adenosine signalling in the regulation of gap junction coupling in the epithelium of the large intestine. RT qPCR experiments showed that the cells expressed Cx43, Cx32 and Cx26. In immunocytochemical experiments, the presence of Cx43 at the cell-cell borders was clearly recognized. Using gold nanoparticle mediated laser perforation/ dye transfer assays, we found that specific stimulation of A2A or A2B adenosine receptor subtypes induced a rapid decrease in gap junction coupling. The gap junction coupling was reduced to about 50 % by 50 nM CGS 21680 (A2A) or 100 nM BAY 60-6583 (A2B) applied for 1 h. The decrease of the gap junction coupling was not related to a change in expression of Cx43 as revealed by RT-PCR analysis. Western blot experiments showed however that the stimulation of A2 adenosine receptors induced a reduction of Cx43 protein in the cells. Concerning the activated signalling pathway, two different PKA inhibitors blocked the BAY 60-6583 induced decrease of gap junction coupling. Taken together the findings suggest that the A2 adenosine receptors are linked to the gap junction coupling by a cAMP/PKA-dependent pathway that affected the translation or the degradation of connexins.

Where applicable, experiments conform with Society ethical requirements