Basic fibroblast growth factor stimulates connexin-43 expression and intercellular communication of cardiac fibroblasts.
Gap junctions (GJ) are membrane specializations responsible for intercellular communication and for ensuring electrical and/or metabolic coupling between cells. They are composed of connexins, a family of related proteins. Connexin-43 (Cx43) is a major connexin of the rat heart, expressed by myocytes as well as non-muscle cells. In this communication we have examined expression of Cx43 by cardiac fibroblasts and regulation of its expression by an endogenous mitogen, basic fibroblast growth factor (bFGF). Recombinant human bFGF, administered to cultured cells which had been maintained in 0.5% serum for 48 h, induced dose-dependent and statistically significant increases in Cx43 mRNA as well as protein accumulation, at 6 h after addition. Intercellular communication was also increased at 6 h but not 30 min after bFGF treatment, as assessed using a scrape-loading protocol. It is concluded that the bFGF-induced stimulation of Cx43 expression caused increased coupling between cardiac fibroblasts. This would be of importance in injured myocardium, the increased bFGF content of which might stimulate electrical coupling involving fibroblasts of the scar tissue.
Doble
B W
BW
Division of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Kardami
E
E
D000818:Animals; D015152:Blotting, Northern; D002450:Cell Communication; D002478:Cells, Cultured; D018031:Connexin 43 / Q000096:biosynthesis* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D005347:Fibroblasts / Q000378:metabolism; D017629:Gap Junctions / Q000502:physiology*; D005786:Gene Expression Regulation; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D013268:Stimulation, Chemical; D013997:Time Factors
D018031:Connexin 43; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2