title: Ultrastructural alterations and retention of the C-propeptide of type II collagen in human chondrocytes exposed in vitro to brefeldin A.
abstract: Normal human chondrocytes grown in vitro were exposed to 10 micrograms/ml Brefeldin A (BFA) for 24 h, 1 microgram/ml for 4 h, or 0.1 microgram/ml for 4 h and evaluated for ultrastructural alterations. BFA in the amount of 0.1 microgram/ml resulted in vacuolization, disappearance of the Golgi, and moderate increases in rough endoplasmic reticulum (rER) vesicles. After 1 microgram/ml BFA exposure large interconnected cisternae were identified. BFA treatment of 10 micrograms/ml was associated with large dilated ER cisternae which contained material of variable electron densities. Immunocytochemical localization showed markedly increased type II procollagen intracellular retention in BFA-treated cells. High dose BFA-treated cells showed ultrastructural similarities to those seen in the skeletal dysplasia hypochondrogenesis. Results presented here show that in vitro culture of normal human chondrocytes results in retention of the C-propeptide of type II collagen and marked alterations in cytoplasmic ultrastructure.
authors.affiliation: Medical Genetics-Birth Defects Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048.
authors.forename: H E
authors.initials: HE
authors.lastname: Gruber
mesh_terms: D020126:Brefeldin A; D002135:Calcium-Binding Proteins / Q000032:analysis* / Q000187:drug effects; D002356:Cartilage / Q000737:chemistry / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D002478:Cells, Cultured; D003094:Collagen / Q000032:analysis* / Q000187:drug effects; D024043:Collagen Type II; D003517:Cyclopentanes / Q000494:pharmacology*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000187:drug effects / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D011498:Protein Precursors / Q000032:analysis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*
chemical_list: D002135:Calcium-Binding Proteins; D024043:Collagen Type II; D003517:Cyclopentanes; D011498:Protein Precursors; D011500:Protein Synthesis Inhibitors; C040072:chondrocalcin; D020126:Brefeldin A; D003094:Collagen