%0 Journal Article
%T 7-Ketocholesterol modulates intercellular communication through gap-junction in bovine lens epithelial cells
%A Henrique Gir£żo
%A Steve Catarino
%A Paulo Pereira
%J Cell Communication and Signaling
%D 2004
%I BioMed Central
%R 10.1186/1478-811x-2-2
%X Primary cultures of lens epithelial cells (LEC) were incubated with 7-ketocholesterol (7-Keto), 25-hydroxycholesterol (25-OH) or cholesterol and the subcellular distribution of Cx43 was evaluated by immunofluorescence confocal microscopy. The levels of Cx43 present in gap junction plaques were assessed by its insolubility in Triton X-100 and quantified by western blotting. The stability of Cx43 at the plasma membrane following incubation with oxysterols was evaluated by biotinylation of cell surface proteins. Gap junction intercellular communication was evaluated by transfer of the dye Lucifer yellow. The results obtained showed that 7-keto induces an accumulation of Cx43 at the plasma membrane and an increase in intercellular communication through gap junction. However, incubation with cholesterol or 25-OH did not lead to significant alterations on subcellular distribution of Cx43 nor in intercellular communication. Data further suggests that increased intercellular communication results from increased stability of Cx43 at the plasma membrane, presumably forming functional gap-junctions, as suggested by decreased solubility of Cx43 in 1% Triton X-100. The increased stability of Cx43 at the plasma membrane seems to be specific and not related to disruption of endocytic pathway, as demonstrated by dextran uptake.Results demonstrate, for the first time, that 7-keto induces an increase in gap junction intercellular communication, that is most likely due to an increased stability of protein at the plasma membrane and to increased abundance of Cx43 assembled in gap junction plaques.Gap junction channels (GJ) consist of two connexons that are located at the plasma membrane of two adjacent cells. Each connexon is composed of six subunits, the connexins. These channels allow passage of small molecules, with a molecular mass below 1 kDa, such as small metabolites, ions, and second messengers [1]. The physiological importance of intercellular communication through gap junctio
%U http://www.biosignaling.com/content/2/1/2