title: Lead inhibits secretion of osteonectin/SPARC without significantly altering collagen or Hsp47 production in osteoblast-like ROS 17/2.8 cells.
abstract: In an effort to better understand the consequences of lead (Pb2+) on skeletal growth, the effects of Pb2+ were investigated using ROS 17/2.8 bone-like cells in vitro. These studies revealed that Pb2+ (4.5 x 10(-6) M -4.5 x 10(-7) M) has little or no effect on cell shape except when added immediately following seeding of the cells. However, proliferation of ROS cells was inhibited, in the absence of serum, at concentrations of 4.5 x 10(-6) M Pb2+. Protein production was generally increased, however, the major structural protein of bone, type I collagen, production was only slightly altered. Following treatment of ROS cells with Pb2+, intracellular levels of the calcium-binding protein osteonectin/SPARC were increased. Osteonectin/SPARC secretion into the media was delayed or inhibited. Coincident with retention of osteonectin/SPARC there was a decrease in the levels of osteonectin/SPARC mRNA as determined by Northern analysis. These studies suggest that processes associated with osteonectin/SPARC translation and secretion are sensitive to Pb2+.
authors.affiliation: Department of Pathology, University of Maryland Dental School, Baltimore 21201.
authors.forename: J J
authors.initials: JJ
authors.lastname: Sauk
authors.forename: T
authors.initials: T
authors.lastname: Smith
authors.forename: E K
authors.initials: EK
authors.lastname: Silbergeld
authors.forename: B A
authors.initials: BA
authors.lastname: Fowler
authors.forename: M J
authors.initials: MJ
authors.lastname: Somerman
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003094:Collagen / Q000096:biosynthesis*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D007700:Kinetics; D007854:Lead / Q000633:toxicity*; D009942:Organometallic Compounds / Q000008:administration & dosage; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D015676:Osteonectin / Q000378:metabolism*; D012516:Osteosarcoma / Q000378:metabolism; D051381:Rats; D014407:Tumor Cells, Cultured
chemical_list: D006360:Heat-Shock Proteins; D009942:Organometallic Compounds; D015676:Osteonectin; D007854:Lead; D003094:Collagen; C008261:lead acetate