Novel early target genes of parathyroid hormone-related peptide in chondrocytes.
We have performed microarray analysis to identify PTHrP target genes in chondrocytes. ATDC5 cells were cultured as micromasses to induce chondrocyte differentiation. On d 8 of culture, the cells had a prehypertrophic appearance. This time point was chosen for isolation of RNA at 0, 1, 2, and 4 h after a challenge with 10(-7) M PTHrP. Samples were subjected to a cDNA microarray using competition hybridization. A list of 12 genes (P < 10(-3)), the expression regulation of which by PTHrP was confirmed by quantitative PCR analysis, was generated. This included seven up-regulated and five down-regulated genes. Three genes were known to be involved in PTHrP regulation, and six were previously found in growth plate chondrocytes. Most of the genes (10 of 12) were implicated in signal transduction and regulation. PTHrP also induced expression of the up-regulated genes in KS483 osteoblasts, suggesting involvement in a more generalized response to PTHrP. The vast majority of the up-regulated genes (six of seven) contained cAMP response element-binding protein- and/or activating protein-1 transcription factor-binding sites in their promoter regions. Remarkably, a number of PTHrP-regulated genes contained signal transducer and activator of transcription factor (Stat)-binding sites in their promoters. In transient transfection assays, we show that PTHrP is able to positively regulate the activity of Stat3-specific and negatively regulate the activity of Stat5-specific promoter-reporter constructs in ATDC5 and UMR106 cells. In combination with the expression regulation of genes involved in Janus kinase/Stat signaling, this data suggest a previously unrecognized interaction between PTHrP and Janus kinase/Stat signaling.
Department of Pediatrics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
Jakomijn
J
Hoogendam
Edwin
E
Parlevliet
Razvan
R
Miclea
Clemens W G M
CW
Löwik
Jan M
JM
Wit
Marcel
M
Karperien
D051696:Activating Transcription Factors / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001798:Blood Proteins / Q000378:metabolism; D002460:Cell Line; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D044162:Parathyroid Hormone-Related Protein / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000235:genetics; D050799:STAT5 Transcription Factor / Q000235:genetics; D015398:Signal Transduction
D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D044162:Parathyroid Hormone-Related Protein; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; C494087:Stat3 protein, mouse