In vitro regulation of expression of cartilage-derived morphogenetic proteins by growth hormone and insulinlike growth factor 1 in the bovine cricoid chondrocyte.
OBJECTIVE
To delineate the endogenous growth factors that regulate cricoid cartilage growth at the molecular level. Specifically, to attempt to establish the presence of cartilage-derived morphogenetic proteins (CDMPs), cartilage-specific members of the bone morphogenetic protein family, in newborn bovine cricoid chondrocytes and to assess the expression of these endogenous growth factors with the addition of exogenous growth hormone or insulinlike growth factor 1 in an in vitro chondrocyte culture model.


METHODS
Basic science molecular biologic research methods, including high-density monolayer and explant chondrocyte cultures with extraction of messenger RNA and quantitation via Northern blot hybridization via radiolabeled complementary DNA probes.


METHODS
Intramural basic science research laboratory.


RESULTS
Both CDMP-1 and CDMP-2 were found in newborn cricoid chondrocytes. Addition of exogenous growth hormone did not appear to influence the expression of CDMP-1 or CDMP-2. Addition of exogenous insulinlike growth factor 1 appeared to down-regulate the expression of CDMP-1 but had no effect on the expression of CDMP-2. No major differences in CDMP level of expression were noted between high-density monolayer cultures vs explant cultures. No tissue specificity differences were noted in regulation of CDMPs between cricoid and articular chondrocytes.


CONCLUSIONS
Our preliminary studies indicate the presence of endogenous morphogenetic proteins in newborn bovine cricoid chondrocytes. These novel polypeptide hormones (CDMP-1 and CDMP-2) have not been previously reported in laryngeal cartilage chondrocytes. Change in level of transcription of these morphogenetic proteins under various in vitro conditions suggests that these proteins are subject to regulation and/or play a regulatory role in cricoid chondrocyte growth and differentiation. Further experimentation is needed to confirm these findings.
Tomaski
S M
SM
Craniofacial and Skeletal Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD, USA.
Zalzal
G H
GH
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D003413:Cricoid Cartilage / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015342:DNA Probes / Q000737:chemistry; D005786:Gene Expression Regulation; D055428:Growth Differentiation Factor 5; D013006:Growth Hormone / Q000494:pharmacology*; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D019485:Bone Morphogenetic Proteins; D015342:DNA Probes; D055428:Growth Differentiation Factor 5; D006133:Growth Substances; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C090394:cartilage-derived-morphogenetic protein-2; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone