Synthesis of fibronectin and laminin by type ii pulmonary
epithelial cells.
Dunsmore, Sarah E., Yu-Chen Lee, Cara Martinez-Williams, and D. Eugene
Rannels.
Departments of Cellular & Molecular Physiology and Anesthesia,
The Pennsylvania State University College of Medicine, Hershey,
Pennsylvania 17033
APStracts 2:0164L, 1995.
Previous investigations demonstrated that type II pulmonary epithelial
cells regulate extracellular matrix deposition as a function of time
in primary culture. In those studies, the matrix fraction was
analyzed as a whole. The present work is focused on two components of
the type II cell matrix, fibronectin and laminin. These glycoproteins
have differing effects on differentiation of type II cells in primary
culture. Fibronectin synthesis was quantitated between day 1 and day
6 in the cells, matrix, and medium; laminin synthesis was quantitated
only in the cells. Although total fibronectin synthesis was regulated
as a function of time in culture, reaching its greatest value on day
2, the average proportion of newly-synthesized fibronectin in the
cells (35%), medium (50%), and matrix (15%) remained constant over a
six day interval. Between day 2 and day 6, the relative abundance of
fibronectin messenger RNA increased 6.5-fold. Rates of cellular
laminin synthesis did not vary with time in culture. These results
support a role for differential regulation of fibronectin and laminin
synthesis to determine the composition of the type II cell
extracellular matrix.
Received 26 May 1995; accepted in final form 30 August 1995.
APS Manuscript Number L164-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.