Identification of novel regulators of osteoblast matrix mineralization by time series transcriptional profiling.
Bone mineralization is a carefully orchestrated process, regulated by a number of promoters and inhibitors that function to ensure effective hydroxyapatite formation. Here we sought to identify new regulators of this process through a time series microarray analysis of mineralising primary osteoblast cultures over a 27 day culture period. To our knowledge this is the first microarray study investigating murine calvarial osteoblasts cultured under conditions that permit both physiological extracellular matrix mineralization through the formation of discrete nodules and the terminal differentiation of osteoblasts into osteocytes. RT-qPCR was used to validate and expand the microarray findings. We demonstrate the significant up-regulation of >6,000 genes during the osteoblast mineralization process, the highest-ranked differentially expressed genes of which were those dominated by members of the PPAR-γ signalling pathway, namely Adipoq, Cd36 and Fabp4. Furthermore, we show that the inhibition of this signalling pathway promotes matrix mineralisation in these primary osteoblast cultures. We also identify Cilp, Phex, Trb3, Sox11, and Psat1 as novel regulators of matrix mineralization. Further studies examining the precise function of the identified genes and their interactions will advance our understanding of the mechanisms underpinning biomineralization.
The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK, kstaines@rvc.ac.uk.
Katherine Ann
KA
Staines
Dongxing
D
Zhu
Colin
C
Farquharson
Vicky Elizabeth
VE
MacRae
D000818:Animals; D002113:Calcification, Physiologic / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D017886:Durapatite / Q000378:metabolism; D005109:Extracellular Matrix / Q000235:genetics / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000378:metabolism / Q000502:physiology*; D010011:Osteocytes / Q000378:metabolism / Q000502:physiology; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D012886:Skull / Q000378:metabolism / Q000502:physiology; D014158:Transcription, Genetic; D015854:Up-Regulation
D016326:Extracellular Matrix Proteins; D047495:PPAR gamma; D017886:Durapatite