Changes in cell surface expression of fibronectin and fibronectin receptor during liver regeneration.
The surface expression of fibronectin and its major integrin receptor in liver, integrin alpha 5 beta 1, was studied during liver regeneration after partial hepatectomy. Using immunoblotting, plasma membranes isolated from livers at different regeneration stages were found to contain 6- to 8-fold elevated levels of fibronectin, alpha 5 and beta 1 at 12-24 h after the operation. Normal levels were gradually restored during the following 8-9 days. The membrane-associated fibronectin lacked the ED-A domain, suggesting that it consisted of plasma fibronectin. A prominent fibronectin fragment (180 kDa) was present at 12-24 h after surgery, possibly reflecting turnover of the pericellular matrix during cell division. Indirect immunohistochemical staining of liver sections revealed beta 1 and fibronectin mainly in the sinusoidal region of the hepatocyte plasma membrane. The distribution was not markedly altered during liver regeneration. The results suggest that the fibronectin-mediated contacts between the cells and the extracellular matrix increase during the pre-replicative and proliferative phases of liver regeneration. The significance of these results for the growth and for the structure of the liver during regeneration and development is discussed.
Pujades
C
C
Departamento de Biología Celular, Facultad de Medicina, Universidad de Barcelona, Spain.
Forsberg
E
E
Enrich
C
C
Johansson
S
S
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D006498:Hepatectomy; D015151:Immunoblotting; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017469:Receptors, Fibronectin / Q000378:metabolism*
D005353:Fibronectins; D017469:Receptors, Fibronectin