title: Biosynthesis of sulfated extracellular matrices by alveolar type II cells increases with time in culture.
abstract: The aim of this study was to determine the extent to which sulfate incorporated into biosynthesized basement membrane (BM) components increased as isolated type II cells progress toward a more type I cell-like phenotype from 7 to 21 days in culture. Specific sulfate cytochemistry, using high iron diamine, showed that type I-like cells in 21-day cultures deposited a more highly sulfated extracellular matrix. Biosynthetic labeling experiments using [35S]cysteine or [35S]sulfate as precursors confirmed the increased capacity of 21-day type I-like cells to biosynthesize sulfated BM components compared with type II-like cells in 7-day cultures, including a novel sulfated laminin. These biochemical changes in sulfation of BM components coincide with the established phenotypic transition from type II to type I cells during prolonged culture. More importantly, the data suggest that regulation of sulfation constitutes a potential mechanism by which type I and type II cells alter their environment in such a manner as to stabilize phenotype and modulate responses to growth factors.
authors.affiliation: Department of Anatomy, Physiological Sciences, and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Sannes
authors.forename: J
authors.initials: J
authors.lastname: Khosla
authors.forename: B P
authors.initials: BP
authors.lastname: Peters
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016922:Cellular Senescence; D003545:Cysteine / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D007700:Kinetics; D010641:Phenotype; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D011916:Rats, Inbred F344; D013431:Sulfates / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D013997:Time Factors
chemical_list: D016326:Extracellular Matrix Proteins; D013431:Sulfates; D013462:Sulfur Radioisotopes; D003545:Cysteine