Spheroidal aggregate culture of rat liver cells: histotypic reorganization, biomatrix deposition, and maintenance of functional activities.
Liver cells isolated from newborn rats and seeded on a non-adherent plastic substratum were found to spontaneously re-aggregate and to form, within a few days, spheroidal aggregates that eventually reached a plateaued diameter of 150-175 micron. Analyses on frozen sections from these spheroids by immunofluorescence microscopy using antibodies to various cytoskeletal elements and extracellular matrix components revealed a sorting out and a histotypic reorganization of three major cell types. A first type consisted of cells that segregated out on the aggregate surface forming a monolayer cell lining; a second type was identified as hepatocytes that regrouped in small islands often defining a central lumen; and a third group of cells reorganized into bile duct-like structures. This intercellular organization in the aggregates was paralleled by the accumulation of extracellular matrix components (laminin, fibronectin, and collagen) and their deposition following a specific pattern around each cell population structure. Determinations of albumin secretion and tyrosine aminotransferase induction by dexamethasone and glucagon at various times after the initiation of the cultures revealed a maintenance of the hepatocyte-differentiated functions for at least up to 2 mo at the levels measured at 3-5 d. It is concluded that cells dispersed as single cells from newborn rat liver conserve in part the necessary information to reconstruct a proper three-dimensional cyto-architecture and that the microenvironment so generated most likely represents a basic requirement for the optimal functioning of these differentiated cells.
J
J
Landry
D
D
Bernier
C
C
Ouellet
R
R
Goyette
N
N
Marceau
D000418:Albumins / Q000096:biosynthesis; D000818:Animals; D002449:Cell Aggregation; D002454:Cell Differentiation; D002470:Cell Survival; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D007633:Keratins / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D008099:Liver / Q000166:cytology*; D051381:Rats; D013997:Time Factors; D014444:Tyrosine Transaminase / Q000096:biosynthesis
D000418:Albumins; D005353:Fibronectins; D007797:Laminin; D007633:Keratins; D003094:Collagen; D014444:Tyrosine Transaminase