Naslov
Comparison of Gene Expression in Osteocytes versus Osteoblasts

Autori
Paic, Frane ; Wang, H ; Kronenberg, MS ; Kuo, L ; Shin, D ; Harris, SE ; Kalajzic, Ivo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Journal of Bone and Mineral Research / - , 2008, 387-387

Skup
30th Annual Meeting of American Society for Bone and Mineral Research

Mjesto i datum
Montréal, Kanada, 12.09.2008. - 16.09.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
osteocytes; osteoblasts; gene expression analysis

Sažetak
Osteocytes represent the most abundant cellular component of mammalian bones with important function in its remodeling and turnover. However, little is known about the osteoblast-to-osteocyte transition process. We utilized visual markers to selectively identify osteocytes and osteoblasts. This was achieved by development of dual GFP reporter mice in which osteocytes are expressing GFP(green) directed by the DMP-1 promoter, while osteoblasts are identified by expression of GFP(blue) driven by 2.3kb of the Col1a1 promoter. Histological analysis of 5-day-old neonatal calvaria revealed the expression of DMP1 in osteocytes and Col2.3 in osteoblasts and osteocytes. To isolate distinct populations of cells we utilized fluorescent activated cell sorting (FACS). Cells expressing GFPgreen were sorted as osteocytes and cells expressing only GFPblue were collected as osteoblasts. Cells suspensions were subjected to RNA extraction, in vitro transcription and labeling of cDNA. Gene expression was analyzed using Illumina WG- 6v1 BeadChip. Following normalization and statistical analysis (SAM, LIMMA), 30% of genes covered with microarray oligonucleotide probes were called present. We selected 380 genes with statistically significant changes in expression from osteocytes versus osteoblasts. Among them, 230 had higher expression (≥ 2 fold), and 150 genes were expressed at lower level (≤ 0.5 fold) in osteocytes vs. osteoblasts. We utilized gene ontology databases to arrange related groups according to known biological functions. As expected, among genes clustered to osteogenesis and skeletal development, Bmp3, Bmp4, Bmp8a, Dmp1, Enpp1, Phex and Ank were highly expressed in osteocytes. Interestingly, five of six differentially expressed genes involved in Wnt signaling pathway were downregulated (Fzd1, Wnt10a, Wnt9a, Sfrp2, Dkk3) with an increase in Dkk1 expression. Muscle proteins or related molecules were all (38) upregulated. Most of the transcription factors that are significantly changed were upregulated in osteocytes, including Notch3, Dlx3, Sox11 and Crem while most of extracellular matrix proteins were downregulated (12/26). We also found that most of the cyoskeletal protein (38/7), genes involved in cell differentiation (25/16) cell organization and biogenesis (25/10), cell migration (12/0) and localization (11/0) were upregulated. Therefore, utilization of isolation of osteocytes and osteoblasts allowed us to identify a number or genes and pathways with potential role in osteoprogenitor lineage differentiation and function.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA