EFFECTS OF VARIOUS TYPES OF EXTRACELLULAR MATRICES ON ADHESION, PROLIFERATION, DIFFERENTIATION, AND C-FOS PROTEIN EXPRESSION OF PORCINE THYROID-FOLLICLE CELLS
S. Toda et al., EFFECTS OF VARIOUS TYPES OF EXTRACELLULAR MATRICES ON ADHESION, PROLIFERATION, DIFFERENTIATION, AND C-FOS PROTEIN EXPRESSION OF PORCINE THYROID-FOLLICLE CELLS, Cell structure and function, 20(5), 1995, pp. 345-354
Thyroid follicles in vivo are embedded in extracellular matrix (ECM).
The composing epithelial cells are in close contact with ECM at the ba
sal side. To examine cell-to-ECM interactions, we studied adhesion, pr
oliferation and differentiation of porcine follicle cells monolayer-cu
ltured on type I and IV collagen, fibronectin or laminin. At 3 h in cu
lture, laminin had the lowest rate of cell adhesion. In proliferation,
type IV collagen induced the highest level of nuclear bromodeoxyuridi
ne intake. In a functional differentiation, laminin had about 3 times
as much triiodothyronine production as the other ECM molecules. In con
fluent culture cells, we also examined an expression of c-fos protein,
a transcription factor that plays crucial roles in signal transductio
n. Immunocytochemistry detected the protein mainly in the nuclei. West
ern blot showed that laminin induced the highest level of its expressi
on. Thyrotropin (TSH, 10 mU/ml) did not affect adhesion of the cells o
n any of the substrata or proliferation of the cells on fibronectin; n
or did TSH affect c-fos protein expression of the cells on the substra
ta except for fibronectin. Our results suggest that type IV collagen a
nd laminin, major components of basement membrane, play positive roles
in proliferation and differentiation of follicle cells, respectively,
while laminin has no positive effect on adhesion of the cells at earl
y culture; that the cells express c-fos protein even in contact inhibi
tion of growth and its expression is regulated in part by ECM; and tha
t ECM controls some behaviors of the cells in a TSH-dependent or TSH-i
ndependent manner.