Cell-to-Cell Communication and Expression of Gap Junctional Proteins in Human Diabetic and Nondiabetic Skin Fibroblasts: Effects of Basic Fibroblast Growth Factor

Endocrine ◽  
1999 ◽  
Vol 10 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Kay M. Abdullah ◽  
Girish Luthra ◽  
Jerzy J. Bilski ◽  
S. Ahmed Abdullah ◽  
Lawrence P. Reynolds ◽  
...  
2002 ◽  
Vol 64 (2) ◽  
pp. 503-513 ◽  
Author(s):  
Jasodhara Ray ◽  
Joanna Hogg ◽  
Andreas S. Beutler ◽  
Hideichi Takayama ◽  
Andrew Baird ◽  
...  

Endocrinology ◽  
2005 ◽  
Vol 146 (9) ◽  
pp. 4054-4060 ◽  
Author(s):  
Nurul Kabir ◽  
Kirti Chaturvedi ◽  
Lian Sheng Liu ◽  
Dipak K. Sarkar

Abstract Folliculostellate (FS) cells are known to communicate with each other and with endocrine cells via gap junctions in the anterior pituitary. We investigated whether TGFβ3 and estradiol, known to regulate FS cell production and secretion of basic fibroblast growth factor (bFGF), increases gap junctional communication to alter bFGF secretion from FS cells. FS cells in monolayer cultures were treated with TGFβ3 or vehicle alone for 24 h and then microinjected with Lucifer Yellow and high-molecular-weight Texas Red dextran. Ten minutes later the transfer of dye among adjacent cells was recorded with a digital microscope. TGFβ3 increased the transfer of dye. The TGFβ3-neutralizing antibody and the gap junction inhibitor octanol reduced the effect of TGFβ3 on the transfer of dye. The TGFβ3-induced transfer of dye was unaltered by simultaneous treatment with estradiol. The steroid alone also had no effect. TGFβ3 increased total and phosphorylated levels of connexin 43. Estradiol treatment did not produce any significant changes on basal or TGFβ3-induced increases in connexin 43 levels. The gap-junction inhibitor octanol reduced TGFβ3-increased levels of bFGF in FS cells. Taken together, these results suggest that TGFβ3 may act on FS cells to increase gap-junctional communication to maximize its effect on bFGF secretion.


2007 ◽  
Vol 18 (1) ◽  
pp. 34-46 ◽  
Author(s):  
Elke De Vuyst ◽  
Elke Decrock ◽  
Marijke De Bock ◽  
Hiroshi Yamasaki ◽  
Christian C. Naus ◽  
...  

Gap junction (GJ) channels are formed by two hemichannels (connexons), each contributed by the cells taking part in this direct cell–cell communication conduit. Hemichannels that do not interact with their counterparts on neighboring cells feature as a release pathway for small paracrine messengers such as nucleotides, glutamate, and prostaglandins. Connexins are phosphorylated by various kinases, and we compared the effect of various kinase-activating stimuli on GJ channels and hemichannels. Using peptides identical to a short connexin (Cx) amino acid sequence to specifically block hemichannels, we found that protein kinase C, Src, and lysophosphatidic acid (LPA) inhibited GJs and hemichannel-mediated ATP release in Cx43-expressing C6 glioma cells (C6-Cx43). Lipopolysaccharide (LPS) and basic fibroblast growth factor (bFGF) inhibited GJs, but they stimulated ATP release via hemichannels in C6-Cx43. LPS and bFGF inhibited hemichannel-mediated ATP release in HeLa-Cx43 cells, but they stimulated it in HeLa-Cx43 with a truncated carboxy-terminal (CT) domain or in HeLa-Cx26, which has a very short CT. Hemichannel potentiation by LPS was inhibited by blockers of the arachidonic acid metabolism, and arachidonic acid had a potentiating effect like LPS and bFGF. We conclude that GJ channels and hemichannels display similar or oppositely directed responses to modulatory influences, depending on the balance between kinase activity and the activity of the arachidonic acid pathway. Distinctive hemichannel responses to pathological stimulation with LPS or bFGF may serve to optimize the cell response, directed at strictly controlling cellular ATP release, switching from direct GJ communication to indirect paracrine signaling, or maximizing cell-protective strategies.


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