title: Matrix protein gene expression in intervertebral disc cells subjected to altered osmolarity.
abstract: Physiologic loading of the intervertebral disc may lead to changes in the osmotic pressure experienced by the resident cells. In this study, changes in gene expression levels for extracellular matrix and cytoskeletal proteins were quantified in disc cells subjected to hypo-osmotic (255 mOsm) or hyper-osmotic conditions (450 mOsm), relative to iso-osmotic conditions (293 mOsm). Important differences were observed in osmolarity and between cells of different regions, corresponding to the transition zone and nucleus pulposus. Under hypo-osmotic conditions, gene expressions for aggrecan and type II collagen were up-regulated in the transition zone, but not in the nucleus pulposus cells. Genes for the small proteoglycans, biglycan, and decorin, but not lumican, were up-regulated in transition zone cells following incubation in either hypo- or hyper-osmotic media. The same genes were down-regulated in nucleus pulposus cells under either hypo- or hyper-osmotic conditions. Differences in the response to altered osmolarity between cells of the intervertebral disc may relate to their different cytoskeletal structures or embryological origins.
authors.affiliation: Department of Biomedical Engineering, Duke University, Box 90281, 136 Hudson Hall, Durham, NC 27708-0281, USA. junchen@duke.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Baer
authors.forename: Phil Y
authors.initials: PY
authors.lastname: Paik
authors.forename: Wei
authors.initials: W
authors.lastname: Yan
authors.forename: Lori A
authors.initials: LA
authors.lastname: Setton
mesh_terms: D000464:Alginates / Q000737:chemistry; D000818:Animals; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis* / Q000235:genetics; D007403:Intervertebral Disc / Q000378:metabolism*; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D011509:Proteoglycans / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D014158:Transcription, Genetic
chemical_list: D000464:Alginates; D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger